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""I 00.TE O£SIOM ,:)jffllflt H B'?EI!& I ?(?Ql} I~~ ---C.0..-TNO.°""""' l?d~CC~llW~[Q) SHffiS 2006--161 ' 1-<r: 0 'ct: l I~ ·~ I I>- '<r: ,'.:E !I! ~-·-ffll~ I ' ~ (Q) ~ ~ o ) i ffJw >, a, g .... . ·-f LL 0 ll l!l!lJ ;111 ©b alil I' !Uhl VrS 'E. -----·-~--···-·1---- ~~o~.JJq n n Bil .~, r~S . :7. J 6 !/t ~ "'L~·~ --,O&!)\H--~ ! tr··' ·,:a .• :.a,1:snr· :,}!g >- • j! >:: • V ; , . lc/l L;J 1-1 --., ,_.,, ,-.1, I ! • ; ' . 111 -........ I Z r-~"i':K~ ---r- Q -~,. lD ~ >-f,~.~---N ~ _;, i~, . ~ . ~ . \' w >:: : -4r . l) ~ - . 't\ . . t::::J~ l<; .) IV -., I ·f';.:&-.u t::::Jll llf::::Juj.,'1 $ \'* 11 11 ~ ! I ii I I ~~ . ~ . I I I I I I I I I I S :--..... .I 'fft::::::J1tQc;:::nnrc:r . .:=t_.-1, -1!Vo 1---nnouno/acl 1111111111·1 I A.) I I I ,' ·3·N 3/\ V SNOA-1 i: / ii V ~ i ~ ~ 6 id B H ! ~ •• g i \ I l1L1 I dQ} li'ii'iJ ~ li'ii'iJ = : lg I ! 'I 'II! II 11 I " I ! ' I I ~ !Jl!i j- j !' ·~ I i 11 ! ,I. 1--f 1 ! ffl ~ .... ~ "-' = ,::) ,!-~-~ al •• •• 0 D I I -\ \ \ \ I ,J I I ; --mio=,e, l 01-:101 -~ COUNTY I 01-20101 -MS1: ~ COi.NiT 02-2010 TREWR CIIAY, PLS I 02-2010 ,_ '-201 - ~-MAP COALFlElD NlEX .filiEEI._ QESCRlPTIQN 1. VICINITY MAP ANO INDEX 2. LEGENDS AND ABBREVIATIONS 3. SUMMARY OF QUANTITIES 4. EXISTING CONDITIONS, SHffT KEY, t£G£NO, CONSTRUCTION NOTES 5. TEMPORARY EROSION AND S£01MENT CONTROL Pl.AN ANO L£GENO 6. TEMPORARY EROSION ANO SEDIMENT CONTROL PLAN 7. TESC SEDIMENT DISPOSAL. AND TURBID WATER DISPERSION LOCATIONS 6. TEMPORARY EROSION ANO SEDIMENT CONTROL NOTES AND DETAILS 9. TEMPORARY EROSION ANO SEDIMENT CONTROL DETAILS 10. PLAN ANO PROFILE. STA. 0+00 TO STA 8+00 11. Pt.AN ANO PROFILE. STA. 6+00 TO STA. 16+20 12. PLAN ANO PROFlt£, STA. 16+20 TO STA. 24+00 13. PLAN AND PROFlt£, STA. 24+00 TO STA 29+00 END or PROJECT 14. WOl.AND AND RIPARIAN MITIGATION PLAN, STA. 0+00 TO STA. 7+00 15. CROSS SECTIONS AND HABITAT MITIGATION DETAILS ! 16. LOG PLACEMENT, LOG TABLE, ANCHORING NOTES, SNAG DETAIL ANO NOTES 17. HABITAT MffiCA.TION D£TA11..S: FABRIC APPLICATION 16. HABITAT l.lmGA.TION ENI-W«:EMENT: FENCE AND WETLAND SIGNAGE DETAILS 19. Pl.ANTING TABLES ANO NOTES 20. Pl.ANTING Pl.AN --~ ,. 1 --13 ----1 '2013 =~ PROJCCTNo.~ _ .... -I '""'IJ SURVEY No. - ""·L-.--"'-RADEllA 1-13 ~· ~ King County Department of Natural Resources and Parks Water and Land Resources Division Stormwater Services Section Capital Services Unit Christie TNe, Director Department of Natural Resources end Pans MAY CREEK DRAINAGE IMPROVEMENT SE May Valley Rd.+ 148th Ave SE City of Renton Planning Division f:;i King County CCI -.. ---~ w--~-~ -------T-.~ MAY aEBC DRANA<lE IMPROVEMENT l 2 2013 w::NTY MAP AN> K'IEX ft)) SHm 1 " 20 SHEETS 2006-16 PROJECT LIMITS: ""' I '"'" NO. CUNmTY UNIT I ~ "· --0105S I 01-20.1 .-m DtG COUNTT 01-:cno UMJ am: ~ COUlm' o:l-2010 lllE.VOR CRAY, PU 02-2010 -.... ~ .... -- LENGTH: x PROJECT NUMIURS "" -00N ALnwJSER P.L ==., 000G a.. --= srlcwc 1 DEDllllN1PEll:111.1W1E1J..A SUMMARY OF QUANTITIES AS-BUILT ""' I TOTAL NO. QUANTITY ~ 7 -, ~ - - - - - - 1 ·-o,J I 1(11J KCFCZD No . PROJECT No.~ I '201, """' ~. , ·zo\3 """""'"'" • DMSIOH No. - ""· UNIT I IT[M "· PRO,,JECT NUMBERS "'" --,, ~ -.. ~ City ot Renton 3 lann1~n n,.,,~,-~ King County ~'CREB!bfwNAGE IMPROVEMENT ~"'------~-~ :-..=-FEB t ~CFOUNffl/ES cnn..r-r- fPJ~cc~or~[Q) AS-BUILT SHEET 3 o; 20 SHEETS 2006-16 ~' 1. HOl.D PRl£ONSTR1JCTlO MEETING. 2. ESTMll..lSH REQUIRED SICNl,GE AND TRAF'FlC Pl.AN REOUIREMOITS. 3. STNCE OR FUG THE LIMITS Of' CONSTRUCT10N. SU NOTES 13, 16. AND 17 FOR """"""""' """" 4. l.OCI.TE AND w.RI( UTll..lTI£S S. INSTALL lDIPOIWIV EROSKIN COK1R01.. MfA.SURtS SHOWN ON SHEETS 5 TO 9. II. INSTALL CONSTRUCT10N ACCESS RAMP NID CONSTRUC1lON omw«:£ PAD AS NEEDED AND APPROVED IN 1HE f1aD BY ENGINEER. 7. INSTALL STAC:ING AND TIJRN N10UND AREAS AS APPROVED IN THE F1E1.D Bl' THE """"" S. TO t.llNtMIZE DISTlJRS\NCE lO DCIST1NG NATM VEGETATION, MN::H1NERY ...cctss ALONG TH[ S1l!EAU W1l.l ONLY BE Al.LOWED Af'PflOXD.IAffiY ~ 50 FEET AS SHOWN OH SHEEI'S 5 AAD 11. 9. ROICIIIE fl.OW OBSTRUCTING '111..i.DWS AS DCSCRIBED "" NOTES 1J TO 15. 10. RO.ICM: SEDIMDIT AND REED CNURY GRASS AS DESCRIBQI IN NOT£S H!i TD 21. 11. RtMOIIE N« TEMPORAA'l' COHSlRUCTION EHTRI.NCES MID ACCESS RCW>S lWiT ARE NOT NEEDED FtR MITIGATION CXlNS'iRUCT1DH 12. CONS1JUJCT MffiGO,TJON ANO REVEGETATE AS SHOWN ON SHEETS 14 TO IS. 13. Willow REMOVAL WILL OCCUR IN SEl..£CTED l.OC\110NS FROM STA 0+00 TO STA 5-+-,40; SEE TABL£ ON SHEET 10 MID DE:TAI. SHEET 15. 14. WIU.OW ~ ANO ROOTS rnu ARE UMITlNG Tl£ STREAM FLOW WIU. BE REMO'JE[l Bl' tWIO AND/OR HANOHEUI SMAil. t.W:HINERY TO MINIMIZE DIST\IRBmCE. WU.OW B1WCHE$ lWiT ARE NOT UMITlNG STREAM Fl.OW WILL NOT 8E ROltMD. EXACT WLl.OWS TO BE R£MMD Will. BE DIRECTED IN THE FIELD Bl' THE EHGINEER " "'"""'· 1 S. WOODY MTM VEGETATION TKO.T IS ROIO.'ED W1l.l BE MlA.O£l) ANO SPREAD CNER REED CN1ARY CRASS TO SHADE OUT GRASS AS DIR[CTEO IN THE fl£LD BY lH£ D1G1NEER OR BIOlOGISf. ~EPIMfNI_ NfD BffP CNi:Y!X GBAS$ BEMPYN NQJFS 16. SEDIMEHT RO«WAL. IN lHE OWINEJ. Will. OCCUR FROM STA 5+40 TO STA 26+26 17. REED CANAR'I" GRASS REMOIIAL IN THE C-EL WILL <X:CUR IN sn£CT l.OCI.TIONS FROM STA 0+00 TO STA 29+oo. SEE TABLE ON SHED 10. IS. MACHINERY FOR RDIOVING SEDIMOIT AND RUD CJ.HAR'( GRASS SHAU. BE OPERATED F'ROM THE IWII<. NIJTES Cl'.lHlNJEO lHIS PJGE "' ------ --SEC. 2, TWN.23, R. 5 E. W.M. ', "--· 11 ",~~-U. "AV ll"lU:Y RD ~\ I CN \\ SEDIMENT AND REED CANo\RY GRASS ROIOVAL SIW.l. BE 00N£ IN THE ORY. A SlREAM BYPASS PL.AN SHALL BE SUBMITTED TO THc: ENGIHEER IN ADVANCE OF INSTAI..LATION OIV[RSION ~ DEWA.TERING SYSl£M PlAN TO BYPASS THE SIRfAM AROUNO WORK ARU. IN 100 TO !500 FOOT SEGMENlS Sf.&HDNG AT llif llf'SIRE&M fNP Of It1E e@IFGI 'iBfA &NO MMIG !lO'ffli$TRfAM SHAU. BE SUBMITTED TO THE ENGINEER IN ADVANCE OF INSTAL.LA.TION FOR flNAL APPROVAL. PRIOR TO BYPASSING THE STRfAII TI£ CONTRACTOR SIW.l. SCHEDULE A F1SH REMOIIAL WITH THE ENGINEER AND PROVIDE AT LfAST 7 DAYS NOTICE. NO !IQY. BYPASS WORK SliAU. .Bt....S:L!iBIE OH A FRIOliY. THE KING COUNTY BIOLOGIST WILL PERFORM THE flSH REMOVAL PRIOR: TO IHSTAUATION Of EACH OF THE STRfAM OIVERSIClN SEGMENTS. 20. EXCAVATE SEDIMENT AND/OR REED CANARY GRASS FROM NOW DRY CHANNEL 21. R£TURN STRt.lM rt.ow TO lHE CHANNEi. UNOCR OIRE~ OF OfGIN:(ER. PRIOR TO REINTRODUQHG THE Ft.OW TD THE NEW!.Y EXCAVATED c:JimNEL. A SECOND COfFEROAM AND SUI.IP PUMP SHALL BE INSTALLED AT THE DOWNSTRU,M LIMITS or THE CONSTRUCTION AREA.. TD ENSURE TKO.T STATE -TER OUAIJ1Y C>H BE MET, FLOW Wilt. BE IKT!!OOUCED TO THE NEWLY EXCAVATED CHANNEL. ANO TURBIO WATER Will BE PUMPED OUT AT THE DOWNSlR[AM END OF THE CONSTRUCTION ARfA NID Will. BE DISCHARGED TD THE TEMPORARY WATER DISPERSION AREA. UNTIL lHE WATER FLOW THROUGH THE CHAHNU MEETS STATE WATER CIUAUTY STANDARDS. NO TEMPORARY EXCEEDANCES 0~ STATE WATER QUAUTY STANOARDS ARE ALLOWED. ~ •• M ~~~ ;iJ OESJGN I EGfNO DISDNG I f9fNO -S£D1MENT REMOVAL ARfA IN-SIRfAM Wll..l.OW PRUNlNG ARfA lllUU>IO BUrFER (110') -TOE (IIO!TOt,Q OF SfRENol --------YUNI: -·--·--·-·-FENC( ·--POI KING COUNTY CAO R£GUI.ATION (FOR P\JRPOSCS OF THIS PROJECT ""' -------- STREAM BUFFER (165') PER KING COUNTY CAO REGUL,•,:noN (FOR P\J!!?OSES or THIS PROJECT OM.Y) PLANTIHG Mlt\GATJON LINE (15' BUFFER) AND PROPOSED CONSERVATION EASEMENT BOUNDAAY •• ------~ -0-* UNtS _ w ___ 'i'--...mi "ETlMO -,oo'ffl f\.oODP\.J,111 *.S.l-G.>I.Z. .... "' ' ~~ \ -~- ~ 0 ... -· --~ OD0:18101-201 KING COl.wrr 01-2010' ,_,. -~ COl.wrr I 02-2010; -DOOi ALnwlSER P.E. ~ -llOUC OIN I 1{2013 IKCFCl.D Na. ------J DAl.E PROJECT No. 1048119 'annin M1~~~Md-l.li'O'ial@jlf DRAl<AClE IMPROVEMENT SHEET 4 " 11'ltWR CRAY. PIS f 02-2010 --~[.l».ll -HEl.SON I 1t20u lSUIN£I' ..... _____ _j IEIQltlfllllm M.PADO!I -"'''''" '™""' "'· W--Land--:-...::::."""]:[8 1 a-r ..... o-..... llllsIN, OONllT1CNS, 8IEET ICEY, -CONS1RJC1DI NalE9 f?J~rc~ur~@ 20 s,ms 2006-16, I I j! I I I\ I : Bt S 2 !:! !:! ~ ~ ~ ~ ~ ' • i ' ! • • • • • • • • ' • ! •• ! • • ...... ' • ! I I 111 I ! ~ ~ ' ; i i I ' !I UI , , , ~ • ~--• •• ,. •! ~-' s I / I j' ' I ' ' l --~ ~ ; ; !I if!, ~ ' • l !I !! ! . ~ I i j! ;111~ ~~~,~~n I I 1li~~ i •• ; \i :~ 1 11 ~·r ii a . ~-~ .i Bl a ! " ~ -~---1: __I -~---• 8 g g : ~ ~ ~ ~ O 0 §~ i; .. I ' ·~ ~~ ~ r· Ul~ ,; ~n r· ' -~ iJJ •· I ~~; (t': rr, I" ll "'."'. 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I :tr = \~~~~ = ·C=:::11· ,c;::a =· """' IWPACTS TO IMTURE ~ATION WR.L BE MINlMIZED OR AVOIDED TO TliE MAXI .. UM EX100 POSSIBI.£ UNDtFI lHE OCRrel10N OF ECOLOGIST IN THE flEl.D. HO IU.TURE TRErS SHALL BE RflilCMD. METHOD TO AVCYID I .. PACT: N'f'ftOXUU.TaY EVEllY 50 FEET, ON SDUTHERLY SIOE. EXCWATOR Will ACCESS CREE( AT THE DIRECT10N OF ENGINEER DR ECOLOGIST. SEE BELOW. .. ----',I, "\ \ \ \ \ I ;: j ~- I'?-\ --_v,_ \ I \ 1 \ WNC~ • -i~ ~ \ ~v, " \ \ \MARSH " I _.. $~TALL 3-S ~ BARBED ~ \ / \coNSTRUCTION EQUIPMENT WILL" \ fREEK i l "'~ WIRE FENCE T-POSTS; REMCM: SIDMENT .....J,.~ \ NOT CROSS EXISTING BRIDC'E \ \ • \\ I > 1~:i~:;5~~~s '~:\::: :i:,t.:"' '" l~ \ ', ,1~\ [ ~ ~""" \ "~""-~= ~" I ;b~\ g'~ \ '1 '~,_ - .._ 0 st' + .. 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Y)_§._Q ,0 "' ,I,,,, • ,j....,_ ,l,.o. ru,j..,.,, ,JJ 305.0 "" "'-• ruv, '" "" IJOO.O 15+90 16+20 16+50 16+60 17+10 17+40 17+ 0 18+00 18+30 18+60 18+90 19+20 19+50 19+80 2o+10 20+40 20+70 21+00 21+30 21+60 21+90 2 +cr1=1ent~ 23+40 Planning o· . . n 1v1s1on 300.0 23+ 70 -24+00 24+30 24+60 CALL 2 WOAKNQ DAYS BEFORE YOU DIG 1-800--424-5555 (""°""""'"""' UTl\.rn ,oc,.,.,.s .. £ .,.....,, ) ---01-201 --~ >L 1/2013 ~ -=-01-2010 ~ DOUG CHIN 1/201.1 KCrt:ZO Ho. ---,!!ING COUN1T 02-201 P!IOJECT No. -1~19 lRC\OII ot.o.T. PLS 02-2010 ---,,...,,J ...,., ... -.... ---DllDIII> 1,1. !UD£l.lA 1/2013 t.lAINITNANCE • --"""" ~ -DMSION No. ' II I\ l'UN....,"""" STA 18+20 TO STA M+OO '" SHEET 12 °' 20 SHEETS ~~~~~!'.JPlfYCPB3C DRAINAGE~ ---; fflf'T€J.r ·-2006-16 '"'60 \Vl~/Q) ~-s ~ @!(~ ~'\"... 'J~ NOTE: --. :'~ ~lU-r: ~~~8M~~ ,-T-"/-• 1 , /', ...... _ I I'..................... "'<<~ "' ........_ I '-.... / ~o / " l I / <o UN0£R lHE OIR£Ci10N OF ECOlOGIST IN TI£ FIELD. NO MATUR£ 1REES S1W..i. BE RtMO\IED, -----~ -WETHClD TO .waD IMPACT: N'PROXIWATD..Y ~ -...... '-. #,, 50 FEET, AT ONE SIDE. EXCAVATOR WILL .-ccESS "-.. ~•. ' fi" L CREEi< AT THE DIRECTION OF ENGINEER OR ".._.__--.......:;::::---•-11 J::::J•,~· SEESHEET11. ,, -......__-..::::-.__, -. -..., -c:::r. c::::::,:·,c::::::::.. ... ............ --.......:::: --::,,_ -.,.,,, -. ',,, . ~~- ' -· ', ~. "'-~-~ IN ~NCTION WITH SEDIMENT, ALSO , t::::::::., 1:::::::1. . ",, ---f REMOVE VEG[TATJON OBSTRUCTING CHAHNEI. ' CC:::, . ~ ', ~==:m~~~PER ~~f::::=, ',, It- CROSS SECTION DETAIL SHEET 1 5 >UING '", STATIONS 5+40 THROUGH STA 26+26. @~ t::ai::a, """' ',-a ~~1~/l}E~CE~~DT~:~~-... , ... __ CONNECT TO EXISTING F(NCE ', A.S NEWEO TO 0£LINEATE '-..__ BOUNDARY or CONSERVATION """"" REWO'JE smWENT STA. 5+40 ro STA. 26+2& (.,1 \ SEE TYPICAL SECTION, SHEET 15 1,."°\._ f, -~ , ', "" , ,,.... .., I ',, ""~~' lt '\, "'-........_ ~ ! ',," ', I I ~~· ''<:. ,! \ ~STALL .3-STRANO BAR&D WlRE • FENCE WlTH --__ ~op~~ti 0 :~: .. __ -- ~1u~~r,TO ~ ·-~ SOUNDAAY OF \ ~ 1 -"~~ I c. CONSERVATION \ RDIO','[ \IEGET ... ~,f,NQ REID~'--•-'•----. EASEMENT '\_ N<JIE: GRASS OBSTRUCTI CHANNEL ALONG STA. -----<l;.~.. 1. ST>aNG AAE'A SHOWN ON SHEET 5, (SEGAY PROPER1Y) 2&+26 THROUGH STA. +00 ~ -oiii'---, "&..\. ~ SPLIT RAil ~ ..... c ,_, blQo~---f--f---~Ji~ EXlSTIJ'IG EDIMENT ---- ·-· -·- fm_s.o m 8tL a.EVATI N 308 ; -··-+··-·f-----1-I--0 1-1" oOW + w a:: 1-~ ~ ~M lvvir glj~ ~1!i11~~r UlWC,Q. 315_0 310.0 305.0 -~0_9.,Q 23+70 24+00 24+30 24+60 24+90 25+20 25+50 25+80 26+10 26+40 26+70 27+00 27+30 27+60 27+90 28+20 28+50 28+80 29+10 29+40 29+70 30+~;0+30 30+60 30+90 31+20 31+50 31+80 32+10 32+40 \,;ffy Of A CALL~~~YS ---101-201 -IOIC COUNTY I 01-20101 --~ COU!ffY 02-2010 -lllt'IOII CRAY, PIS I 02-2010 '.-20! -srt- -..!!!!!!.&! ~ -~ e.c .!.m.!! 1/2013 KCF"CZ!I No I l'ROJECf ~-li)la\19 l~I'"'"''° -011111Et M. IWlCl.U, l:U w.iNTENANC[ OMSKIN No. -~ _Planntn 0 ,,~~ton ..,...;;;'!;;~~~-·· M!~~~--1 ~ jSHEET MAY aEEK. DRAINAGE: IMPROVEMENT --..-~1 --~1-UOII ~T--r::,,.., ,-.. '01J IUNNDPAOFU STA ZMOO TO STA 21HOD BO OF f'fO.ECT IJlJ Is er;;~ uw ~ /JJJ 13 o, 20 SHEETS 2006-16 I I I I ' ! ................. : _ --·+----~f-.12f~.:~::1!~:P~HCf ~···-·····--···------ = -··--·; _-----:..j--~ •"*·-·····+-····-~" 1 " 0 :~" ... 0 ~ 0 .. 0 .~. 0 '. .. 0 ... 0 ... t'-... -.. 0•2"0.=a ....... 32([6 .. JT.s.o ____ _ _ __ 31.£0 JJ.0.Q. ___ .. j •••••• --··-..; ! -., -,·,x\ ',)...~~10.0 .;_. --·---··-·····-······---.,--.. -----!---··-·- --i -_]_ i---J ___ i __ .. .. Ja5.0 .... ~l'.IS:-00 ... ____ ,. _____ 1 ··-··-~-~w .:?5-9.9 _ #_\JAQ=~~o .~/···/ ; I 1~1 I j ..... J .... .305..Q ... ~CTnO "" 15 ,, 5 t 5-0 1p 15 ~ ··········2;··············".iJ· 35 ··-···· .. ···.;p··· 45 ·so·-ss ·······oo·-··-····s'i···-·-···10··-···* ao as \ LLWE EXISTIN" / CLEAA PLASTIC TYPICAL SECTION HABITAT MITIGATION ALCOVE GRADING STATIONS 2+33 TO 3+04 AND 5+09 TO 5+53 SCli.E: It 1·-10·. V: 1·-10' """" """ Cl.SON. P. AND r. STOCICCl,l,l,E. 2010. llET£RMNNG THE ORDINAAY HICH WA1£R MARK ON STR£Al,IS IN WASHtNGTON ST4TE. SECOND 11£.'AEW ORAFT. WASHINGTOH STATE DEPAR'JMEHT or ECOLCN.Y, SHOREI..ANDS 7 DMRONWEN'TAl ASSISTANCE PROCRAM, I.ACEY, WA. ECOI.OC'Y PUBl..lCATlON if(NH)a-001. FlELO STAI(£[) BY KING COUNTY ENGINEER Ill, EJMRONMEN'TAL UNIT MARCH 2011. CAl.l. 2 'MlFICHl DAYS BEFaE YOU co:, -(IIHDERGR(MNI mvr, l.OCAllOMS ""' APPROlC.) --0905e I 01-201 SUIM.'IIII< O«.l QOUHTfil 01-2010 SUMY W ..,..a CQJM'( 02-:20101 lR£\Gil CR.W, PU I 02-2010 -- -~ M.nlAUSER P.[. ~ --- ~ ~~ ~ MTE , ...... 001Plat M. IWlC1.lA 2"""13 2 1:ZOIJ 2'201J 2-13 KCfCZO l<lo. PROJECTl<lo.~ SURVEY No._ -""'"""' DIVISION No. \ MAY CREEK 7 / / / " SOIL COVER I 24· -FIELD. VERIFY I I ~·,-.....,,-..;: / '\_ E.lRfH BERlil / (El<ISTING SOIL)""\ / / / / . ~ M,! King County O.,,.,....ol~--=.::..~-2· ---0-T_,,..._ n MAY CREEK DRAINAGE IMFft)VEMENT !! ""'""'"""'l.N!I ~ HABITAT lil'TIC¥.llON DErM.8 ".,,,, ~IEU~fE[Q) ,, ssm 15 " 20 SH[E'ts 2006-16! ·1 ~" =i,""'"'"-"I""' I ±· . I A"'" F 1"''""''&• 1 • . ' """''1 wlw'l:fi : ····•···· : ·~ J J J J I . Y"ootj"'-u,J 02D.OO ™" ~::::r:!"'. i,. °'""""""" nla.d,, ..le ei ·""' ro• """" """"' • .. .I . ,.;,,.,. lo,;. "'.,,ko j J : JI. : J : .. · 1 · . ~ t:_ .•• ;... ~ ~.L .~;...,.J_ .. :_ .. -1 ...• L ... 1 ____ : _ _:_r .,,,:=~ ~~ .... i.. : 1,~~w~ 1,rniE ~P~D ANC~IN~ : 1~~0.00. - .:;;oo.oo .. JO;oo 20;00 · 11 : .. , t I : ... , ~"'¥i#-,1~11r··· ···f·· 1~40;<>D 10.:00 / 20;00 I Jo;oo i 40,:00 I 50;00 I s~oo-r~ ao.:oo f9o~ JTooJJOTlUJ.Oo 10.:00 l TYPICAL SECTION -HABITAT MITIGATION LOG PLACEMENT HABITAT FLOODPLAIN AREA AND ALCOVE STATIONS 2+33 TO 3+04 AND 5+09 TO 5+53 SCI,.[: It 1·-10·. V: 1"•10" LOG TABLE # of LOGS LOG SJZE LOG I ROOlWAO OR LENGTH WFTHOUT (W/OUT) >=:NE AArAS , 18·-2•· dbh ,o• -16°-18" dbh ,o' rootwods 12·-19· dbh ,o· roolwoda 16 total FLOODPLAIN ROUGHNESS ~ I 12"-H"dbh I ,o• I •M ~ 12"-18"dbh ,o· """"oo• 60 total 2 I I 27'min I .... 76 total --09c,e I 01-201 -DON N..lHAUSE!I P.[. -KU«; aJI.INIY 01-2010 -.,._ ....if1NC COUNIY 02-2010 -TRE\l:IR CRAT, Pl.5 02-2010 =· -- ~ ----~~ _!'j ""1t I CIDIQII DllERm M. RAOEU,t z "' 1J'?!11J 1/?<\IJ -- mn '-=t...:: ::ff'°-. ~----'~ T-lll a,w,cr SNAG DETAIL "' KCR:20 No. Pl!OJECT Mo ~ 1 12013 '"""' ~ --- 1'2013~~~-• L'.B::\ " ~ ANCHORING NOTES: 1. HABITAT LOG STRUCTlJRES SHAU BE SECURED WITH A S/16 INCH NON-GALVANIZED CI-WN, DOUBLE WRAPPED AROUND THE u.RGEST Cu\SS LOG Of THE ST!IUCTURE, ANO ATTACHED TO AN (ARTH ANCHOR OR EQUIVALENT THliT IS SIZED FOR THE COt,tBINEO REQUIRED ANCHOR HOLDING STRtr,IGTH BASED ON THE FOUOW!NC: LARG£ HABrr ... r LOG: J,650 l.B/r,.c:H LOG; l,l(OIUl,I liABfTAT LOG: 2,05,3 LB/E,,lCH LOG; SMALL 1-WMTAT LOG: 1,242 LB/EACH LOG. THE LOG smuCTIJRE WITH TWO LARGE 1-lASfTAT LOCS SHALL HAYE ONE ANCl-iOR FOR OCH LOG. CIWN JOlNED WITH A LOK-A-LoY 10 CONNECnNG UJ<IK OR [QUIVAL£NT ANO 81.1.1. PEEN THROO TO LOCl( N\Jf. CHAIN SIWl. BE PLACED A MINIMUM DISTANCE FROI.I THE £ND Of THE LOG EQU,f,J.. TO 1/J OF TliE LOG L£NCTH. SCORE LOGS TO A DEPTH OF 2 INCHES TO Rfi:ESS CtWN. SLACK AT SURFACE 'MU. B£ L.£SS TtW<I 6 INCHES. [l,IBED ANCMQRS A t,1iNli..Ut.o OF 15 fEET OEEF' BELOW FINISH EL£VAT10N . 2. TliE CONTRACTOR SHALL SU8Ml1 AN Al«:liORING Pl.AN FOR REVIEW AND APPRDVAL PRIOR TO PLACEMENT. J. SWU!R I.OGS IN CLUSTERS Will UNDERLAY AND BE PINNEO l"D THE ANCI-IOR LOG. SlolAl.1.ER LOGS WlU BE PINNEO TO THE .WCHOR LOG BY PRE-ORIWNC 5/8 INCH Qi,r..MEfER HOLES ll-lROUCH 80TH LOGS ANO INSERTING 5/8 INCH REEWI TO nJLL LOG DIAMETERS BENT OVER FlUSH TO THE LOG SURFACE A MINIMUM S INCHES. 4. ANCHOR SElllNGS 51-1,\U BE FlEl.D ITSrm BY AN APPROVED METHOD TO CONFIRM fHAT THE REOUIREO ANCHOR ttOl.CllNG STRE~ IS MET 5. THE COKTRACfOR SIW.L IHr<lRM fHE ENGINEER A MINIMUM or ONE DAY PRIOR TO ANCHOR \NSTALI.JinoN ANO ITSTING. s. 1l1[ CONTIW:TOft 51-1,\U IHF"ORM l'HE ENGINO:R ONCE INSTALLATION IS COMPl.£TE. LOCATION'S or THE HABITAT LOGS STRUCTURES TO B( STAKED IN lli[ FIELD BY KING COUNTY SURVEY. 7. tr REJECTION OR REFVSAL OF AN ANCHOR, AN Al.TE:RNATM.: LOCATION Wlll BE !OENTIFIEO BY THE ENGINEER SNAG NOTES: 1. wn..DUFE SH.liG TO 8E Pl.,\CEO AS WlECTED BY EOONEER OR lllOLOG!ST. 2. AU. SNAGS SHAU. BE WESTERN RED CEDAR OR DOUGlAS-FIR TRrES WITH A SUBSTANTIAL PORTION OF THOR UWBS LEFT INT>CT. DO NOT TRIM TOPS, AS CWU,GED OR BROkO( TOPS ARE PR[RRRED. PROVIDE LOGS WITH NUMEROUS UNTRIMMED LIMBS. WITH A MINIMUl.4 OF 6 LIMBS. LOGS USED FOR Stw::$ W.Y BE PARTW.LY HOU.OW AND CONTAIN CAVITIES AS UlNC AS "fHEY ARE GENER.,\I.LY SOUND AND INTACT. J. S,W:,S ~ BE A t,jJNIMUI.I Of 10 INCHES IN OIAMETER AT BREAST HEIGHl" (OBH) WHEN INSTAU.ED ,.,,0 SHAI.L 8E PUCEO IKTO TI;[ GROUND TO A DEPTH EQUAL TO 1/J OF TRff HEIGHT anew GROUND. 4. Stw::S WITH SU8STANTIAL ROOT MASSES ATTACHED W.Y SE PI..ACUl TO THE DEPTH INDICATED AND 8ACKFlLLED WITH OUAARY SF',\LLS ANO SOil ONLY UPON APPl!CWAI. BY Tl-IE ENGINEER. City ot Renton Planning Division CAll. 2 WOflKNQ DAYS 8EFOfE YOU OIQ HO<r4.24-5555 ~RGROIJN[l UTIUfY LOC,.'10NS .. £ -0>.) s,rr, 16 o, ~ ~~,g_L.2..Jouy CREEi( CRAlNAClE IMPROVEMENT w,nwuodt.nclR-~ ------~'!?rrren 20 LOO f'l.AC&IEM", LOO TAB.E, ANCHORNQ ...-.-.I SHEETS I 9UiODETALl#CNOTES , ...... ,~ 2006-16 -= u I'/ It; IJ)) --~ St.OPE SURFACE SWILL BE SI.IOOTH BITORE l'VC[I.IENT FOR PROPER SOIL CONT..CT STAPUNG PATTERN AS PER WMWACTURER'S RECOMMENDATIONS WOOD STAKES PAITTRN AS• SPECIFIE:0. DO NOT STRETCH COCONUT fll!(R MATTING TIGHT - ALLOW THE ROUS TO MOLD TO ~ IRR£GUl.ARl11ES FOR SL0P£S LESS THAN 3H:,V, ROUS W.Y B£ Pt.ACED IN HORIZONTAL STRIPS !F THEIi[ IS A BERM AT THE TOP Of" THE SLOPE, .o.t!CHOR UPSLOPE or mr BERM ~ ,,- I.IIN. 6" OVERLAP ANCHOR IN 6"x6" MIN. TRENCH AND STAPU AT 12" INTERVALS Wl11i 2",2",12" WOOD STAKES OJ6" O.C. BRING MATERW.. DOWN lO A I..E'/t:l AA.EA, TURN THE ENO UNDER 4" TO FORM A CUFF AND STAPLE AT 12" INTERVALS. INSTAI.L AS (16" ffT x24" WlOE) COIR WRAP AT TOE Of' SLOPE ONLY AS 0.RECITO BY ENCINE(R WIDl THE OVER1AP DOWNSLOPE "-'ID DOWNSTREAM. ANC!iORING SHALL BE SU.Ill.AA. S£to, FERTILIZE, ANO MULCH BUORE MATilNG lt,1ST...U..,..TlON. PV,NTINC OF SHRUBS, TREES, ETC. Si-101.A.D OCCUR -101-201 DIG_~ 01-20101 AFTER INSTALLATION. COCONUT FIBER MATTING DETAIL (EROSION CONTROL BLANKET -ECB) ~ -DOI<! "l.TIWJSal P.£. ~ WT MSC -,l!ING ro..ffY j~-:a;J_tOI -DOUG Cl-i.+ 1, /20131 KCFCZD No. I PROJECT No. 11143119 _rrrl ... ~ __ M_RADEl.LI, !!1..1~~ -PAff NFJPJP?· rm DAL[ NEtsoN J 1f201J !SURI/ET No. ------1 - ------l-------.--------------, ' ~@fl UmJ ©@@lll?lil@~ I SEE ~NG NOTES AND PL.ANJlNG PL.AN SHEETS rn°,~---- ---+-----------~f--PJ..ANiltlG..wtwlW_SIAK.ES._--jl----__ · -+,_ /T -~"' "~ -~~~ TYPICAL SECTION FABRIC APPLICATION == H: 1· ~ 2S: V-. 1· •2.5" City ot Renton P!ann;~--" ·,s,on ------: --~---- CALL 2 WOfO(NQ DAYS BEFORE YOU Dk) 1-800-424-5555 (U~""""'D ~rJY ~-~ ~OO~:_) M'J King County -- MAY CREEK ORA1NAOE IMPROVEMENT SHEET 17 ==~ 2 ·--~-Uo- ~T ...... ""'9clor 1.L.rAT t.lTDA.110N CETAUJ """"N'l'UCAllON rt;~ur~© " 20 SHECTS 2006-16 i<s> " w:,@~ @@>'·' K1HG COUNTY WETl.>NO/STFIEN,1 PROTECllON ~ ~ NOTES: THE WETI.AND/sn.&t I it SfiNS ~tw..M PostID NI 61'0FrLW!Y OF Tl-![ MmGATK>N ARE,\ Notl/OR TH:£ COHSEINATK>N ~~ .e,~gHALL Bftf;b,ENr I;; ... ~~:mrm~.;.E =~y °!st~"!TTACHEO 'fli' :',NO/Off "'i<s> w@'-' ~@'<, FAAlil FENC(S. ~·-F~~i<s> .L.1----;~~~----=~"'K\.«¥11ti=11"2"--"' .... -~ ~T \l'-' ""'<,ti~ ©@U" .. ,r ---101-201 -~ COUNTY I 01-20101 SU1MV -,wl?IC COUNTY 02-2010 -lREYDR CIU.Y, PLS I 02-2010 IWf NFJSQN Q2 -2tl! - SCAIL H: 1· a 2.5'i V: 1· •2.5° EW!BED WIRE fENC£ INSTAUATIOH NOTES: I. INSTALL ON l'tRIM£TER OF CONSERVATION EASEIIENT, BOTH MNKS, FROM STATION 7+!IO TO STATION 211+00. 2. USE EXISTING PROPERTY FENCING WHERE AVAIUBLE. j M i<s> ~ w:,@r:;, ~ti©@ ©®'(§S . ,,. 3 RAIL CEDAR SPLIT __BAIL FENCE DETAIL ffi NOT 10 SCALE 14 IJr r a.tt_ ~ ._ DON Al.11'WJSE1' P.E. ~ 000000! -~ ._ DmJ1ED: II. RODEllA 111·-w t J-RAIL cmo.R SPUT RAil FENCE INSTAUATION tlOTE: 1, INSTALL ON PERlM£TUI Of WETI.ANO MITICA~ ARrA PER SHEEr 14. .!.G:!ill. .!G!:!ill KCFCZll "'°.,· 1048119 I ""'~ -~~----i 1/2013 ISUR'oa' No. -------1 ill~~ WETLAND PROTECTION SIGNAGE i<s> ~ w:,@~ ~ti©@ ©®c§i PLAN VIEW 3 RAIL CEDAR SPLIT RAIL FENCE PEDESTRIAN-ONLY ACCESS ~OT TO SCALE City of Ri ill " ~ "' t CALL 2 WOFl<NO DAYS BEFOfE YOU C*3, H00-424-5555 {\IOU~ lflUf"/ U>C<llOO<S -.......,,) ,-,ann,n I Mj King County g OJ#~ ORANAGE IMPAO'IEMENT 0...-ol--ond---........ --SHEET 18 " =-..:=:..rfs l 2-l?f1'WITATYTl».mN ENtt.tlCFM"'NT ~ r ..... a.--l''fa«::E NC) WETlAfC) SCWACE DETALS 20 SliEETS 2006-16 !Rl~((;~or.,~© .... Mavr.Lntek RJparlan Buffer Planting-1··:~"' Seaso~urated Areas, • • • • • • • j Stations 7+00, 13+50 to 19+00 ··--·----·- uo ..... ~---T-..... --~-r-.... u-,. -·= ----~!Jasl,t ... _F-. -·= ,. --.. --"-Z-;~ , . ....... --.... _ .... _ SP..,U'~j'~I_-,---.._ ,. -----u..-...J'l-.lfl·-1·-,;;i,... ..-1·0.c. 1'-..... -...6'I.ms,112-l"~ -----J·o.c. "" --Sill:a-Live-...r.i.....112-r-"" Plat3'0.C. May Creek Riparian Buffer Planting-0 o o PermanantJy Saturated Areas, 0 ~ ~ o O ~ O Stations 7+00 to 13+50, 19+00 to 29+00 ®@~ ----------j'.Q .... l'lm9'0.C ...., --J' .... 111"-l" ··-,_ u..-.6'1-.ut-i--,.- -J'O.C. ll!II!'..mciti fl ~ tQI£S ~~ BE Mi.OWED AT OTHER TIMES 5. Pl.ANT STAKES ANO lREES 1¢?. ··-~ ---101-201 , .• --COUNIY I 01-20101 9-'r -~ coutf!Y 02-2010 --~, =. DOUG c- l1'tlGt CllolY. PlS I 02-2010 -rwc NnWI oa -~ __ ... IWICl.l.,I, -•-1- =~ I PROJECT No. 1043119 ~~ ~~ ~lES ON SHEET 16. City of Renton Planning Division CALL 2 \YClfl<N3 DAYS BEFORE YOU DIG HI00-4.24-5556 {ua:~ llD.JTY l.OCAMo« "'I:-·· M.l~"_:~.J..2 lzouy CREEK ClRAINAClE ~ ssm 19 o, 20 ----ssms 2006-16: ' ! • -- ~MAP SEC. 22, TWN.2SN, R. 5 E, W.M. -' ' ' ' ' / c?~~· ,,,., / - SE MAY YAL.l.£y RD olfr .of . .)' --·-R•,co,u,i -Pan ·-=., ·~ NE 2SIH ST = G1 Cl C2 C3 SWP'1 SWPP2 L1 L2 '\,'4 .. 1: c~.e..,. ---.:... . -,,.,.,..~ ' ' ' , ,---. ' ' : . ' . ' < : ~ ' ' ' INDEX DESCRIPTION ..... ' VICINITY MAP AND SHEET INDEX 'l i ------- \ I ' ' EXISTING CONDITIONS PLAN, CHANNEL PROFILE, LEGEND AND ABBREVIATIONS ' ' PROJECT LOCATION GRADING PlAN AND PROFILE -LONG MARSH CREEK AND MAY CREEK SIDE CHANNEL CROSS SECTIONS AND LOG DETAILS TEMPORARY EROSION ANO SEDIMENT CONTROL PLAN ANO NOTES TEMPORARY EROSION AND SEDIMENT CONTROL DETAILS PLANTING PLAN AND NOTES PLANTING SCHEDULE AND DETAILS 2010-2 ~~· -,,,Do,,Ntl'IO,--,P.£. 7-2011 ! ---e-2010: =· -7 2011 ----,-2010 O<Q<EO,~Nol-9-2010 -WES"···-· P.E. !PROJECT No. 7-2011 Julio T LO. 7-20\1 -81' I I»,~ I D£SQI OOD!m L 11U.XlNGER 1-2011---! ~"16~~~ 10<8!64 t4 King County Department of Natural Resources and Parks Water and Land Resources Division Stormwater Services Section Capital Services Unit Christie True. Oinlctor Depactmer,t of Natural Resources and Parks ~.,;.·~~. ~· LONG MARSH CREEK SEDIMENT MANAGEMENT CONFLUENCE TO RIVER MILE 0.05 City of Renton _Flanninn r,,. .. . - ?"'') _,, ,~/- "' FEB II 2 2013 M)KingCounty ~or-...-.... ,.,.... w_....,,.,,,,., __ s----~ISl<',i ... 1/lfft LONG MARSH CIEEK SEDIMENT MANAGEMENT OONFl....lJENC: TO RM. 0.05 YICNTY MAP N<> 9£ET NlEX ~·-·- <G~UW'~[Q) SHECT Gt " 8 SHEETS 2006-42 I • ! 1 ~ 1 C< •• ~ ...... "' I I I I ~ ! ! !! 1 1 ~ ~ 1 ~ ' i i ~ X ui ~ ~ r-z a o"' .. " ;,....,5. t,ir-z ~~G> " a:: -~> ,'::0;::o '-'.0(.1) ;Ii:::! :c ~Mn " "' 8 ~ ~ "' \S i' I I I ~ \ \ \a r., \ .\ ' I 'f' 'f 'l' 'f ~ ~ ~ ~ 0 O O 11! I I I a ! r a j 9 r I • . ~ ~ ~ ii ~ ' s g ' e a PA ' i • • 8 " 8 ~ • g n 0 C 8 ~ ,;,r;; 6 z ~~ ~ ~, > 0 ! " N 0 ~ ii"; . ;;.~ I . j~ I -~·1-: : ! ' __ 8 '.. ' "-·-a· 0 0 • ' \ " h i< • • . i ~i '"'i -I I I~ ~ I no ) ~~ , Oz I ~ d ~ ii " n n ~ ~ ~ r 5 n ~ ~ le z z i z p z " ' ~ " . . i ~ ~ " a . < ~ • • . " < ~ C < • 0 IIP I I J • I I f J f l 5 C, l> z 0 1'l ---r-!I I C i / ~ I /___ ~.,, 1// ~ ------t-.,i------,, ( n ! ~~n 1_$::; ____ _ ----------I I I 8~ f \ :l!\:;! is \ ii ! \ I 0 c ! \ I (co ' I • i i ' ! • .. I f 11 ! ~ I ll . I ~ I I ! ! l; ' ' ' ' , } s ' ~ ~ ~ ! I I I I ' • I i X i -' ! ! ' ' ' ' ' ' - ilF--~,~ --,! I_ i;2 1 \ I ~~ ! \ ----1-----•. ' --• __ \ --I --l';-1----\ ! ·~--ti\ I I I i I I I -· · ----1 --i-----r-- ~ i I i I: i 1 ! ! ' ' p I I I I I I I ·----L--~- I ~ I a \~ I 5 I ~ ~-- I ~ l ~. \\ r \i 0 C, l> z i \ 0 "' I ;;,§; ! ~ ii i M ~ I -: ~~ r~~, ~ ~, ·~· i gi~~ M_ ,:: " ~ I i~1: ~ - 0 ~11·8 M ~ ~~! l'e: I·~ r §cffl (o-ij· ~~ ;~~r -~~ ffi~ ~ I J~ ! ' ! r a a i ; ' ' s ~ ~ II § ;! ~ i • ' \ " (") nr -· ::, '<' ::, 5· 0 (Q .... ¥! l i}j· :, -· .... go :, I • ! ,. ,. 'f 0 ~ 3 I! I 0 0 O ~ ~ ~ ~ i ~ = = = c~ ~ !~ 1i fl ; ·- i ;; P, : ;-- I : I &O I I ··~ ~1; m • l ' ~ ~ H I zf " 'A ~ i • \ ' • / {i, \..,· I I / I~ . ..-.-. g: _P ):l i .. ---·-" J ;o ~ !" _;e_ ;,: Sclentlfk "-r;::.mon 1au.n111y 1s1uCondlllon9 ]Plant Sp;i,;iiig May Creek Side Channel PAINT OR OIP EXPOSED r ENOS Of LIVE STAKE WITl1 * 0 0 0 0 • 0 0 0 @ --- Long Marsh Creek Th""'pllcllal 1~--1 .. --"--iim,~ ·~----~------------ 1-------·-----------, __ ------ ~ -- ------,_ Goel'•------,_ _, 9-20101 a-20,0 .. V » ~ ~ » » » '" .. .. '" » » ~ ~----~ ---9-2010 * I Thuja plicata Western 3 Container min 18" ht, I "Island" between rii.iln and Rod fu!I, dense foliage, side channel MIN. 12 NODES WHITE LATEX PAINT PRIOR &LOW GRADE TO INSTAU.ATION ~-~ ".I LIVE STAKE INSTALLATION 1c--1a-ht,lul.-[i1iiii-channet.s10pe""""-"' ~ •• ,,....,...olcalcn,wn -of- ll&B ~· Ill. ful, -lmlo,ge. lHigh .:.;;.,· channel ..;u,., sii-Jii.i" al May ~~ c- :=:::..,--.. 111;;,,--.-.-a1-. i:-1a·.,z1·111..:i-spw1, l0us1an;a1-ont,;g,,----~- eon-11· .,z1· 111 and oPGaCl.·r C1u.-s al11ne on 119> -dlamot ............. u..-.-311'"1cngllllS"I> 13·..,~-----.....,, y;---.-12-----~trMI< -- U..-.-36"b>gal.%"1> 13·oe~---l'V' y;--.-12------~trMI< -- ~1B""..Z1"hlandl5" -]a.-.a1-Mt,;g,,-dlamot ___ ......,.._ C-15"-IB""hl-.... Cluslar$al_on __ alr,;gr, -- ~15·.1a-1,1....-. ... Cll-.allnllan-barO<olr,;gr, --, ___ J_ - 10--1'1111111 ... , • .,.. - 10c.beincll1'11111'1ar'"'p<II -- IO'-'lbic:incll1'11111'10J'"pcl - 1Qcublclncl,pl.igo ClustersadjaOenttolow-<:twna 1QQbclncl,pl.igo ciu.i-~to"""-"'-- 1,.,. ,_ Cedar 0 Comus sericea Rod Osier Dogwood :';-) Symphoricarpos Snowber albus ry Carex Shore lenticularis Sedge Scripus Small-froi microcarpus "' Bulrush <, I Salix iasiandra Pacific Willow I Salix sitchensis S<i<a Willow c__, TREE ST,J(INC "ARSOR Tl£" OR .-,PPROVED SlJSSTITUTE ----, B'-D" "'BVC" LODG£ POU: PINE ST,J(E, 2• !)LI.. (1 PER TREE) DRIVEN INTO UNDISTURBEO DIAGONAU.Y SUSSCML MIN. 2,· 3 6 6 6 20 20 ' symmetrical crown 1 gal Container min two stems 1 gal Container min two stems 10 cubic inch plugs 10 cubic inch plugs Live stake, min 36" tong at Y:," to Y. • diameter. min 12 lateral buds per stake live stake, min 36" long at Y:," to Y." diameter. min 12 lateral buds per stake PV,NT SO lHAT TOP OF ROOT BAU. !S EVEN WITTi THE FlNtsHED GRADE ~~~:E All TREES~· "' ~ 1:R: :~~~ /h J" CONTINUOUS RIM ,= -' :·f!" "' -~-' ~t,.c;.:: 8ACl<F1U WITH MIXTURE OF 1 2 /J {~pf. -'.-;,-.,t' COMPOST ANO 2/3 NATIVE · ,'. SOILS. WATER A.NO TAMP TO .;~ REMOVE AIR POCKETS. -, SCARIFY SIDES Of PLANTING P!T'S PRIOR TO IIACl<FlLUNG. CONE OF HANO .tiOIE: otaouous TREES Slw..L tt,t,VE TWO STAKES FOR SUPPORT. INSTALLED PtRPDIDICUlAALY PER U.S. HORT. STANDS. FlRMEO TOPSOIL P\.ANTINC MOLE FOR All Pl.ANTS T0BE2X0Lo\. OF ROOTBIJ..l. ~ INSTALL LIVE STAKES AT "Island" between main arid ·-.·11· s~ MIN. J6" SPACING INSTALL PER DETAIL side channel "Island" between main and side channel low bank along island between main and side channel Low bank along island BEVELED ENO {,5•) IN SO.L 00 NOT LET DR'1'0UT~ • ' ,on; lf < between main and side channel POKE HOU IN SUB!,R.t,OE wrrn STEEL a<iR. CARHUUY PLANT STAKE IN HOLE. 00 NOT BREAK OFF LEAF NODES. CAflEFULlY FIRM SOIL AROUND INSTALLED lM: STAKE TO REOUCE ilo.lR POCKETS. 3 ·oc staggered. Stakes driven inlo banks distributed along island between May Creek main and side channel 3 'oc staggered Stakes driven into banks distributed along creek LIVE STAKE DETAIL '" v.NT AT SAM[ LEVEL .lS GROWN. TOP OF ROOTBALL TO BE LEVEL W/ FlNISH GRADE FINISH CRAO[ =~y~y-/cc, ;f. ~~;XISTING SOIL 8ACKflU WTTl-1 MIXl\JRE OF A· 1/J COMPOST & 2/J NATM: SOILS. WATER ANO TAMP TD REMOVE AIR POCKETS. SCARIFY SIDES , Z OF PLAWJNG PITS PRIOR 2• DIAMETER or "' :ii TO 8ACKF1WNG. ROOTBAU. MIN, CONE OF HAND FIRMED SOIL FOR ALL Pl.ANTS "BUTTERFLY" ROOTBAU. ""'' PRUNE DEAD OR BROXE.N ROOTS. SLICE THROUGH ROOTS CIRCLING THE BAU SPREJ,D ("BUTTERFLVj ROOTS ON a<iRE ROOT ,le CONTilo.lNERIZED W.TERIAI... ffi CONIFEROUS TREE PLANTING ffi SMALL TREE, SHRUB AND GROUND COVER PLANTING ill irr1 0.'11: ,_o.,,, __ pL '7-2011 ~Dot,a0... ~-2011 PlMINi Julio T""'!f LG. -2011 I PROJECT No. 104a!M I -''-'-·-F,_,, .. 7-2011 ..... llCSIQIENlElEl,LT, """""'"'' OM$ION No. "' ~ Cfty of Renton Planni,.,-"'· _, " l·fli KingCoun!!_ .... _ ~Ell:'m,Tj' ---<=--T-.0-- lfu 1£, rG~ ow~© ,a CAU. 2 WOFIKN3 DAYS BEFORE YOU DO 1-800-424-5555 {VNOCll(il>OU,c iJJ1UTY lOC,.roHS -.....,,) L.ONCl MARSH CREEK SEDIMENT MANAGEMENT CX'.lNFl..lENCe TO RM. O.o5 PlNfTNl 9CHDU.E ~ CETAl.8 SHEET L2 " 8 SHEETS 2006-42 = .. ~ ~ If® ut JO l ' ~ ' ' ---1 01-201 -KING COlMlT I 01-20101 --, M!11E ,wl?NG COlMlT 02-2010 lllE\OR CRO.T. PlS I 02-2010 -- / i] .I. •• . •• ' ""(II' ', aaa ••••••.,• ' .• ~ •• '-'-·.c.. '-1 •• • ,>}, • "">-'-MIT\GATlON Pl.AN NOlES COt<lSTRUCTION N01ES WETI.»ID BUFFER (25") •••• •• / k.. •• '-'-"'-1(, '-I 2 w ___ 11, •••o} •• \ •.. ' ~.,,, '" NOfE: '•)._• .>}. • \ ~ I '- LOC PlACEMEMT TO BE OIRreTED l<I THE F1El.O IJ't THE D1G1NEER ~ II-• I SEE LOG TABlE AND WITIGA'llON CONSiRUC1JOH MOTES SHEET 1&. L0C ............... / k.. •• \ d '-'-2. INSTAI..L SILT FENCES Wl,[!l[ DESIGNATED OM 1. = TO BE PRESERYED Will BE flAGGED IN THE FIELD BY THE ECOLOGIST. l.OCA.llONS SHOWN ON THIS SHEET >PE. CONCEPTUAL ONLY. '11-A ~· \ '-THE Pl»IS. INSTALL Nf'( OTHER EROSION AND --• \ '-SUKMENT CDHTROI.. MEASURES AS REOUESrED BY ------------------------~ . --- ----..;;.. --k.. •• -l ' ...._ 3. El.EVA.TIONS SHOWN A.FIE FINAL GRADE; 6 INCHES ·••••••••• ~'S-.........._ ~ ··~-~ .. I DO'lt: I l'ISTALL-~ING FOR PEDESTRIAN-<lNLY ACC6S, W.X.. GAP 2.75", ffi I 0 -00N AI..TI-WJSER P.C. 2"'01J ~ OOUGCHIN 2-,J -~-2/2013 -Dl1llEI, II IIADEU.A 21201J •a,L "'""- "'""' --1044119 =-- MAINTENANCE OMSION Na. A.Pf>LY SHE£T MULCH AS \ •• \ ,J-'-Of" OVER-EXCA.VA.T!ON WlU OCCUR AND BE DESCRl8ED SHEET 11!. ' • \ '2~ '81.CKfllllD WITH STRtAM8ED GAAVELS WHERE NOTES (8) 4. Pl.NIT WITH • • , " I INDICAlill ON Pl»IS. ""'-"" -= 1 . Y[G[TATIJN FROM TABLE \ \ ON SHEET 10. -._ ...__ 4. [XCA.VAlJON Of Al.CO'JES ADJACENT TO THE ....._ --...51RE,f.M CH,,,N.NEL SHAU. TAJ<[ PL.ACE ONLY DURING ....._ THE FISH WINDOWS AS OESIGNATEO IN THE PERMITS. " 5. If" Nfr GROUNDWATER 1S ENCOUNTERED DURING EXCAVATION, DEWATER BY PUMPING AND BRCI.WCASTlNG TURBID WATER THROUGH PERfORATED PIPE t.lANIFOlD OR EOUIVM..ENT AND DISSIP ... TEO OVER ~ \'EGETAT£0 STRIP IN UPI.AND A.IIEAS OF THE SIT[. If GROUND 6ECOl,IES s.l.TURATEO A BAKER TANK SHAU ' it-BE USED. ~ '-.. 6. ELEVATIONS ASSOCIATEtl WITH CONTOURING 13-...___ ~ ANO FlOODPI..AIN A.11EAS A.FIE TO BE DIRECTED ~ ECOLOGIST IN THE FIELD . • 7, PA.IITIALLY BURY ANO PL',CE LOGS IN THE EXCA.VAT£0 Al.COVE. LOG PL..ACO..ENT SHOWN IN THE PL.ANS A.FIE SCHEt.lATlC; ACTI.IAL PLACEMENT AND ' /-...A.IIR,,.NGEMENT TO BE DETERMINED BY THE ECOLOGIST IN THE FIELD. ANCHOR AS SHOWN IN PLAN DETAILS. 8. Pl.ACE 6 INCHES Of" Slll[AMBED GRAVELS WITHIN '°" THE Al.COVE A.FIE.A., PER TYPICAL SECTION, SHEET 15. Ji/ - 9. REMOVE TEMPORARY ST.0.SILIZEO CONSTRUCTION ENTRANCES ANO Nfr OTHER EllOSIDN CONTROL MEASURES STILL INSTALLED "T THE S!TE 10. PIJNT O..ERGENTS ANO SHRUBS IN ALCO'JES , ,,.lCCORO.NG TO Pl.ANTING PLAN ,, z.,, ·~ ''-. ' \ \ ' \" ' ~ .... ::f"" ' 0 ... ~., ' ~...._(::,(::, ' ,._v'I!" ~V'",._'l".4. ·"'· o" "-" -::-~:,.., ··-~.s.,.G~? " V ~~- MAY OEEK. DRAINAGE IMPROVEMENT SH(ET ~ King County ,__., ___ _ " =.::.i::--=.:-FEBI ---~r ...... - W.l~Pl.W""'1.AN)NDIV'AIWI IIIIQATJON srA. o+oo lO STA 7+<1() ~~CG~U~~[Q) 7 SHEETS 2006-16 -·--1-·-· ·--t·---·--··(---SU.f.U•oo..:l4 .. 19..00.~IW/aS. ltat:O'--T0-31-•. , 320.0.. ...•.. ,_ 7T ·······-;::::..J --~·· ........ -... -._--J20.0 iJ.to.O ..... ..... !oo ... ~ ... W%;,CH72.,7-2·S0 ... /; -~,-'4, .:-'. .. 31.0.0 ................. -i >"-0-~~ffi ~----\---+--"q=::_)_;_ -~---~15-0 .<'<--. JYPtC,ll "'' n.,..·----·· ~ .. .:505..0.-------+-"7 .,. 'i . . I ~ ~ gQ9_ _ ..... 4J25..0 ... _ ·····-·_ro··REiowK:-··-·--· .... ··· ... :~20.0 ............ ~=NG .... : ... :X:: _;515.0-·-··--··- ... '35.W ... 30;00 ... -tt-oo---20;00~ H ~ ············i·~-CANIRf .. :GBi.ss .. ~ .. CIWWEL ..... ' ·-···+-··-·-···-·····---?\- S.s N ~ : ffiPICAL ~CHeN -· -· '·--·-VfGf+Ant"f:.:n.r.M·ovA~SE[} 15; V, I ~' ' .... -~~~~ &!OE 'ti[~ '"""' v ER~ .,., ~v',WA'.V,<-~ {%\ I .- .. -T-fo56"1 ro-,~s.oo ________ J ......... J vu ....... .'0~1s:oo~-2s_!oo--::-J_(J:()(l-=t= j j tJ I I ·····,;1 11J_,J15-<L ·: ~:r:r~:;r.:! L0I __J ~ i_· 1 ~ --c_1-_;.~ .. ! .. --.~-~-i~~t----*-~~~:-~ I j ..... ; ..... 305.CL ! i ~ 1s 10 s t. s.o 1_0 15 to 25 :so···--·-·-.;;--·--.;i;-·--·-··~;-··---·so·-··-··;;·----so ---·$··-···-···10···· 75 ao ·········-a; !~'""" TYPICAL SECTION HABITAT MITIGATION ALCOVE GRADING STATIONS 2+33 TO 3+D4 AND 5+09 TO 5+53 SCAIL H: 1"=\0". V: 1"a10" OHWlil NOTE: OLSON, P. »a> E. STOOalALE. 2010. DETERMl>llNG THE OROINAR'r' HIGH WATER liW!K ON STR9MS IN WASHINGTON STAlE. SECOND REVIEW DRArT. WASHlHGTON STAlE oawm«Hi OF ECOl.OGY, SHOREI.ANOS 7 OMRONMENTAI.. ASSISTNU ~. LACEY, WA. EC0L00Y PUl3UCATION f08-0S--001. RUD STNCED Bl' KIHG COUNTY ENGINEER m, ENYIRONMOlJAl UNIT MAA0-1 2011. CALL 2 WOflCNl DAYS llERllE YOJ ""' -~<IIUlYUlCA---·1 ---101-201, -ICING COtMTT I 01-20101 __,. MSC ...,ifll'ilG C0tMTT 02-2010 TRE\a! CW.Y, PLS I 02-20. ,0 CIEICID! JWf NFJ$QN 02-- -OOJI N..-~ P.E. ~ DOWCHIN ~ "" """" ~lllffl:· llDDIOllEJlm, .... RlDEUA \ 2'-13 2-013 KCrCZD No. PliOJECT No. __ _!__~11_! 212013 SURVEY No. 2 12013 WJNTEtWICE OMSION No. MAY CREEK - \ VE EXISTING SOIL • /5,11,/0 BAGS O BOTH (NOS 1----s'o'~-S~'--~ TO .o.NCHOR PLASTIC FIELD VER1fY / I sono"' or NEW ,.:::.:..,~71 /. . ....,_,.::::::,,--..,;:.7;1~ lSTREAM AI..Covt: / ;,..:. / a I f---/-"'~ -:;:: ' ii "' / :..> Y;, <- /\_ ·,""";-.:; --..!/ / EARTH 8ER"' , --.....: ~ 1'>- / (EXISTWC SOIL)\. ,-.....J,.._-...:. ,....._ I / / I ·-··--·-··-··-··-··-··-··-··-··--·-··- SECTION C . TEMPORARY EROSION ,ty of Ree1$>n CHANNEL ALCOVE GRADING -· NTS . il1111~ LJIVl~IUII ~ King County -"'--'"'-MAY C>lEEK DRAJNAOE IMl'ROVEMENT s.rn 2 " F~-7 SHEETS l&Wl1.ITAl'OII f'I.AN, U ik.HB NC ~T--HAEITAT MmC».llCN CEfAI.S 2006-16 ~~({;~UW~[Q) ~~Fr1 ::::::r,..,*"" -··-~~ __ =r ·~ .. ""P:t:t"~i·l=l:~,J~I~· -l-- ..... 1,= .~20-00. ,K.:f =1~~""1'°"! ·1.~~~i ···· ·· pAootl,c..i ux i ... Jb!''' Jl~o,6 l.. J MA!: J +---'----+------!--i'--l--'-----t-----,-~ . . ·.. . . JO.OU. ~Y~"l>~t-;:_;~,~~;,; ~~:<,, ~*'77' -~···· r,&~ % »~ ~tf::BE11IifJ + I ;ff~' 1 =.oa , I , '~ '.< -. • , • ,_ , , , - ·· '··1 ···1···"'· l·········l····''f nn~"'t··'···· . ,~~1~1~1,~·~1:~:r~ 10.:()0 ! 20.:001 JO;oo 140;00 ! 50;<)0 / so:oo I 70(00 I ao;oo In, ___ I·-· on:on Hl('[.QO 110:.00 --~ TYPICAL SECTION -HABITAT MITIGATION LOG PLACEMENT HABITAT FLOODPLAIN AREA AND ALCOVE STATIONS 2+33 TO 3+04 AND 5+09 TO 5+53 # of LOGS ' ' • 16 total " I " ~ 2 I 76 total -01-:ZOI SCAU:: II; 1"•10'. Y: 1"•10" LOG TABLE LOG SIZE LOG LENGTH ALCOVE AREAS 1e·-24• dbl\ I ,,. 16"-18" dbl\ I ,,. 12·-1a· dbh I ,,. I I I f"LOOOPLAIN ROUGHNESS 12·-, .. -dbl'I I ,,. I 12"-18"dbl'I ,,. I 21·rron I ROOlWAD OR WITHOUT (W/OUT) roolW<lds rool•ods rootwcds ·!- rool•<lds - -00N Al.THAUS£R P.E. -~ 01-2010 ~ OOUGctilN SI.IND"IIIR...P.'IG COI.NTY 02-2010 TREVOR CRAY. PlS 02-2010 --~ -1,,.,_.,,1 __ ... 11.0DEli), --"' '---~ z "' "' " I 2'2013 Ilj I --' ,, ~Cl'CZD No. 2 12013 "l '-::t..:="=-au.sc. ,_mcow.ocT -'llFllFH~ ~_NAG DETAIL ~ PROJECT No. ~19 2120\3 """" '"· 212013 '"'""'""'" • OMSIOH ND. @ .. ~ ANCHORING NOTES: 1. HABITAT LOG SIRUCTlJRES SttAI..L BE SECURED WITH A :5/16 INCH NON-GALVANIZED CHAIN, DOUBLE WRAPPED AAOUNO lttE LARGEST CLASS LOO Of THE STRUCTURE. ANO ATTACHED TO AN tARTH ANCHOR OR [OUIVALENT TliAT IS SIZED FOR lHE COMBtNED REOUIRED ANCHOR HO~NG STRENGTH BASED ON Tli[ FOUOWING: LARGE HABITAT LOG: J.650 LB/U.CH LOG; MEOIUt.l HAEHTAT LOG: 2,05J LB/EACH LOG: St.W.l. tWIITAT LOG: 1,242 LB/EACH LOG. THE LOO STRUCTURE WITH TWO LARGE HABITAT LOGS Selo\LL fi.l.VE ONE NICHOR FOR EACH LOG. CfWN JOINED WITH A LOK-A-LOY 10 CONNECTING LINK OR EQUIVALENT N;() BALL PEEN TliRE"A!I TO LOCK NUT. CI-WN StiAl.l. BE PLACED A l,IINIMUM DISTANCE rno1,1 THE END or TM[ LOO EQUAL TO 1/J Of THE LOO L!NGTtt. SCORE LOGS TO A DEPIB Of 2 INCHES TO RECESS CHAIN. SI.ACK AT SURf...cE WIU. BE LESS TtW<I 6 INCHES. EMBED ANCliORS A MINIMUM Of 1S FEET DEEP BE1..0W f'INl$H El.EVATlON. 2. Tli[ C0HTJW:roR SHALL SUBMIT AN ANCHORINC Pl>,N FOR REVIEW AND APPRCWAI. PRIOR TO Pu\CEMENT . J. St.W.lER LOGS ... CLUSTERS WIU. UH0£RL.AY AHO 8E PINHED TO THE ANCHOR LOG. SIU.Li.ER LOGS W11..1. BE PINNEO TO 1)1[ AlfCHOR LOG BY PRE-ORILUNG :5/6 INCH OW,IETER HOl.£S THROUGH OOT!s UlCS ANO INSERllHG 5/8 INCH RESI.R TO FUU LOO IXloMUERS BENT ()l[R FWSH TO 1'11£ LOG SURFACE A MINIMUM 6 INCttCS.. 4. ANCHOR SETTINGS SHAU. BE FIELD TESTED BY AN APf'ROVED ME!liOO TO CONFIRM ntAT THE REOUIRtD /\NCHOR HOU>ING STRENGTH !S MET. 5. THE CONTRACTOR SHAU INFORM THE ENGINEER A MINIMUM Of ONE D,l,,Y PRIOR TO ,I.NCHOR INST.O.U.O.TION /\NO lESTJNG. 6. THE CONTRACTOR SHAU. INFORM THE ENCINEER ONCE INST.t.LV,.TION IS COMPLETE. LOCATIONS or THE li.l.BITAT LOGS STRUCTURES TO BE ST"'4:EO IN THE FIELD !lY KING COUNTY SUR\IEY. 7. If l!EJECllON OR REFUSAL Of /\N ilNCHOR, AN "1.TERN.\TM: LOCATION WILL BE IDE"lllf1ED !lY THE ENGINEER. Sw.G HOTES: 1. WILOUFE SN,t,G TO BE PLACED AS OIRECTEO BY ENQNEER OR BIOLOGIST. 2. AU. SNAGS sw.t.l. BE WESTEFIN RED CEOAA OR OOUGI.AS-FIR n:tEES WITH A SUBSTANrlAL PORTION or THEIR LIMBS LEFT INTACT. DO NOT TRIM TOPS, AS OAl,i.l,G[I) OR BROKEN TOPS ARE PREFERRED. PROVIDE LOGS WITH NUMEROUS UITTRIMMED LIMBS. WTTH A MlN!MUM or 6 UMBS. LOGS USE0 fOII SNAGS MAY BE PARTIAU.Y I-IOU.OW /\ND CONTAIN CAVITIES ~ l.OHG ~ TliEY AR£ GENERALLY SOUND AND INTACT. J. SNAGS SHAU. BE A M:NlMUM Of 10 INCHES IH OIAMETER AT BREAST HEIGHT (DBH) WHEN INSTALLED AND SHAU. BE PU,CED INTO THE GROUND TO A OEPTH EOUAL TO 1/J or n:tIT HE!Qfr BELOW GROUNO. ... SNAGS WITli S.UBSTAHTW. ROOT W.SSES ATTACHED MAY BE PLACED TO THE OEJ7l1-I INOIC\TED /\NO 8ACKFIU£0 WITH QUARRY SPALLS AND SOTL ONLY UPON APPROVAL llY THE ENGINEER, City of Renton CALL 2 WORKNl DAYS BEFOFE YOO DIO 1-8()1)-424-5555 n, ____ . ..r,,.__,___,_ 1 111 •8 UJVISIO, ~ King County Do,parr,,onl<lf--.... p .... ~13 C-T-- fRf ~((;~llW~[Q) ~•<>£11<;flOlmD IJTll'rr lOCAflONS ..., """"''-l MAY CPEEK DflAINAQE IMPROVEMENT SHEET 3 °' 7 FSWIUl'ATION f'\..m LOO PI..AC&IENT, TAB.ES I SHEETS I 2NAO OETAL NCJ NOTES 2006-161 ---~ -~ --~cot.N!Y TR£"V0R ~Y. FU -' SLOPE SURFACE SH,,t.LL BE SMOOTH BEFOl<E PLACElo!ENT FOR PROPER SOIL CONTACT STAPLING PATIERN AS PER w.NUFACTIJRER'S R£COMMHIOATIONS If TMERE IS A BERM AT THE TO!' OF THE SLOPE, ANCHOR WOOO STAKES PATIERN AS SPECIFIED. UPSLOP£ OF THE BERM ANCHO!I IN 6"•6" M!N, TRENCH ANO STAPLE AT 12" INTERVALS WHH 2",2",12" WOOD STAKES GJ6" 0.C. BRrNG MATERIAL DOWN TO A t..E.V£L AREA, DO NOT STRETCli COCONUT Fl8£R t.lATTINC TIGHT - Al.LOW TliE ROLLS TO I.IOL.O TO fW'( IRREGUt..AAITIES TURN THE ENO IJNOER 4• TO FORI.I A CUff AND STN'LE AT 12" IHT£RVALS. INSTALL AS (18" ttT ,24" W!OE) COIR WRAP Al TOE Dr SLOPE ONLY AS OIRECTED BY EHGINEE!I. FOR Sl0PE:S LESS ~ JH:W, ROI.LS MAY 8£ PLACID IN ttORIZONTAl STRIPS Wffi! THE CM:Rl..AP OO'flNSLOPE: ANO DOWNSTREAM. ANCHORING SHALL 8£ SIMllAR. SEED, FERTILIZE. ANO UULCH BEFORE MATTING INSTALLATION. PI..M'TING 0~ SHRUBS. TREES. CTC. SHOULD OCCUR AFTER INSTALL.ATKJN. COCONUT FIBER MATTING DETAIL (EROSION CONTROL BLANKET -ECB) ~ 01-201 -tx:. M."ll•WJSER P.E. 2'2013 01-2010 =., DOUG ci.. 2'"'013 "'"' ... 02-2010 "'""" ... 02-2010 -~~ 212013 '"""' ... 'M- ~..._ 111.RADtW 2 12013 ~~~~---"""' ~ •• 104311g • I I SEE PLJ.NT1N.G NOTES AND P+P!.AN SHEETS;.,-.---- ---+· -----~------t·--"P~I NffitiG...WU I QW sr,t,K(S--r-: +· ~ /7" -WILi.OW ,STAl(ES ·,-...;.: ........ ·: LL-"'-~ /' "'' , I .II. " · ~ J! ~-. ~~--=: .i!OSION CONTROL CLOTH EXISTIN~ SEDIMENT ~ TYPICAL >cLIIVN t ABRIC APPLICATION SOU:: H. 1· • ZS; v, 1· =2.5" City of Renton Planning Division '>;~~~~~ -7('< ';:-(7:\~s-· -~cfsl<fk/~·~/~'6,_':[~t7 310.0 ------- CALL 2 WORKINO DAYS BEFORE YOU DIO l-800-424-~ [U"l>ERG""""° _ tm.m U)CA!l(lo0$ "'l -OOX ) Ml King1i!Jl.rrfy2 ·20Jj I MAY OEEK DRAINAGE JMPR:l'IBAENT ~.,, ___ _ SHEU 4 w--~-o;,;,;.,n ---~ ~~ FE<ABUTATD<rL»uwrrm,,.,.~ OW' !@..,..,...,~~ " 7 SHEETS 2006-16 --- ,.. ,. X ___l__ X --t-=;---' ---,, . . ~. 1~ ·r-· •---,--- •---•--- ---•---• .. (OJ KING COUNlY wrnANO/STRf.W PROTECTION SIGN INSTAUATION NOTES: THE WtTlANtl/S1RE,.M PROTECTIDlo SIGNS SHAU. BE P0STro ON THE BOUN[Y.RV OF TliE WITIGATION ARO, NIO/OR lH£ CONSERVATION EASEMENT, Ot<IE SIGN SKIU. BE POSTED FOR MR'!' 50-FTET OF TliE IIOUNl»Jf'I' OF THE Wll1GAT10N ARO, NIIO/OR THE COHS£R\IAT10H EASEMENT IN A PROWlNENT LOCATION. SIGNS MAY ALSO BE AITACHm TO NEW NIO EXISTING FARM F'ENCE5. ~f «~v(' «<«<«<~{«<«<«<~~f~v" ~'0;~~~ ~~~tt~~~~~i • //, //~'(/,//. 'TYPICAL • //, /,,:0,0(,0(, ' '-' BARBED WIRE FENCE ' , "'·'" '·'" SCALE: tt 1· ~ 2.5'; V: 1· -z.s· EW!B(I) 'MRE FDIC£ IGTAUATK»I NOTES: 1. IGTALI. ON PERIMETER Of CONSERVATION EASOIENT, 90TH BANKS, FROM STATION 7+50 TO STAn:'.lN 29+oo. 2. USE £XlSllNG PROP(RTY FENCING WHERE AVAllloBl.£.. J ~1. t u ' -,,. ,~= 119" long R,:,~ ·-'" . U_.LHOU '" .J. .. = '" O!KIM I 01-201 3 RAIL CEDAR SPLIT RAIL FENCE DETAIL NOT109:ALI !lr:JII01£ ffi " ~ _,,_ ~ ALT!WJSER P.t:. ::::., .J!!!!&...9::!! -~ --"· RAOCU,\ J-RAIL CEDAR SPUT RA!1. ftNCE INSTALLATION NOTE: I. INSTALL ON PERIMETER OF WUl.ANO wmCATION AR£A PER SHEET 14. ~ KCFCm No. --::,::-:;---I ~ PROJECT No.--"-'''-" 1&1-1~IS1J1MY ...,. _____ -l !G!!QJ~~~ WETLAND PROTECTION SIGNAGE --~-m~~ PLAN VIEW 3 RAIL CEDAR SPLIT RAIL FENCE PEDESTRIAN-ONLY ACCESS ~01 IO SCAl.E City of Renton Plann,n-~- 1T ill " ~ '" t CALL 2 WOFIKNG DAYS BEFORE YOU DIG 1-800-424-5555 (UN!>l;RGROIJJ<O U?llJTY LOC,.!""'5 ""1" •PPOO,.) Mj King County I MAY CREEK DIWNAOE IMPRO'IEMENT ~--SHEET 5 -:'2111. -__ j ---~T,...,-l&WDJTATIJN Pl..N+ HABITAT llifl'DA110N EtH"rrnfT + WETl.AN) SOWE CETALS fOWf© o, 7 SHEET'S 2006-161 ,. May Creek Riparian Buffer Planting-I .. '.~· Seasonally Saturated Areas, ....... Stations 0+00 to 7+00, 13+50 to 19+00 May Creek Alcoves Planting Plan -CJ ......... c--.................. -west of 148th Avenue SE ,_ Lalin Name I Common Name Size/Specifications Quanlity ·----~-•• Eme~nts • to, alCOV9a near alrllam l'lool9'0.C. ----""'"'"""' i,·oC) -$pl.~'f*PI f.UO-O~ £ ..... _.,..,._, ' -~-Pluofl'!anOO,"Ol") -----l'lool9'0.C. ,. ~---"""l"""''l"Ol'.) ----,·-........ ,--s,rubs/Wi11o .. , ........ --PIIIM9'0.C. •• r-,...,.,.. R-.... -.............. ,, ..... J pl.~· fk;pO 1'1111 0-0 F ... P1a .. ror_ --w---,. Pbm9'0.C, ,.., ..... .,..., ........ P,..,rn-........... ,.,,.. .... '" Shrubs/WIiiows r1u,.1·oc u .. Slakeo.1·1-1n•.1·~ t...,.,._,.,,., Pe,rn,,...,.,.. "-"'"""·'"'· 'l"""'~ ----,,. 11,,.n,,.,,,.. 1'11111J'O.C. ,_,,..,,.,.,,, "''""-..,..,.._,., Ll"""'• --Pac1r .. ..;n-u .. 9w.._,·i...,.1ri-ro..-.. ,,. ,., .. ,,.,,,. l'laolJ'O.C. L., .. ,,,.,. , .. , ........... ~ "''-'"'''""' 1"'";"'""'"'1•"'•''4,1" -"'" s,,/iJ,,11<1,ouu suu .... -u..--.,·Loot, 1/l.l"O...... ,,. n"""""' P'"'"l'O.C. "'"''""'" ,.,,,~,, .. '"''""'-'!""""" l'><,r~.,,1._ '1'"""""'"'"'"• "'"'""'"''·····•, .. , . .., Plontl'(H" May Creek Riparian Buffer PlanOng-b O o o "'~~0 o L,"°"°'"'"'""• "°I'"'"'""'""'~.,.. PIO<•C.ono.......t "";m,mO'lono Pennanently Saturated Areas, 0 ~ ~ o. ~ ~ o O ~ """"'"""··-1·•-'" Stations 7+00 to 13+50, 19+00 to 29+00 pi..,roc --------l,fill,{ala --, ......... w 11-.9'0.C May Creek Wetland Enhancement Planting "' ~ -LiYe-l"loos,1/Z'"·l" Plan· west of 148th Ave SE -----. 1.,00 ,-i·o.c. ·----i..v.-...1''-1,Z.1" ··---.. -----,.m ------.,,.,.,.oc. Live-6''-lfl.1" --8IO<l<C,--.! 6"01,, ........... , ............ ,_ -----,.m "'-'>'OC -J'OC. ..................... 12· --......... ..,_ .... ~ ....... oc:. Mffi!'.'-!:IPN Pl Ml NQ1fS ........... I',_ .. ,,,.,. --~~---,.._,roe. """"" """ 1. WIIIGATION P\NffiNC Pl,I.N5 REPRESDfT A CClNCEPnW. Pl,I.NT LAYOUT. AU. WrTICAOON PLANi1NC PR£PARATION Will BE ----l.i..S.-....6"[-.lf!-1" -DIRECTED IN THE FID.D BY THE ECOLOCIST. -..... ,-oc. 2. PlANTN. SW.U. TAKE PUCE l'.lURING nn:: OClRlilAHr SOSON (OCTOBER 15lt1 TliROUGli M.lRCH 31ST). PUHTING WAY •PUHTS W1U. 8C INSTAU.ED THROUGH l'ROPElC {OR EOUIVALDIT). = 8[ AWlWED AT 01llER TIMES AFTER REVIEW ANO WR!TTD,I Af'f"RCWAL BY TH£ ECOlOGIST. NOTES OH SliE£T 16. l. Al'f't.Y SHEET liM.CH AS OIR[C'ttl) BY ECOLOGIST WITHIN THE Fl.OOOPI.MN EXCAVATION AREAS ANO ALL PlNIT1NC AREAS. 4. IN ALL PlANT1NG ARrAS VIH£R£ R££D ~ GRASS IS PRESENT. CCMR REED CANARY GRASS WITH SHEET WULQI (OIi A SIMILAR EW!RIER MATERIAL AS ~ BY THE: £COt.OGISl) AS NEEDED ANO DIRECTED BY £COl.OGIST. STAI(( IN Pl.AC( USING lM: STNCES. .S. PLANT STAKE:s ANO TREES AS OIR[CTD) BY nl[ ECOLOOIST THROUGH nl[ SHEET IIIJLDi {OR £OUW"1.£NT). I. NO TM:KlflER, H£RBICIO£. OR fElmUZ£R SHA1..L BE USED 1H THE PLANTING 1'RU.S. City of Rent CALL 2 WORKN:. DAYS 8EFOAE YOU DIG P1 . on l-800-"24-5055 ann,ng Div;~,-{Ul«RGIIOUNO UlU1Y loc.<nor<s AA£ .,,...,o, -=~ , .• I ,Mo1, MAY CRE8( DRANAGE M='RDYEMENT SHEET ---01-201 ~~-6 -~ 01-2010 =-. DOUG ClflN =~-~ I ~M01J °' !it.W4Y NE: ~ COUNTY 02-2010 "'°""' ~ 104!!119 lllEYOII Clt,o:r. PlS 02-:nno DESll;llUt ~!!ELSON 2/:,DlJ SURYE'r No. ---7 -_,,_ ·-----RBWIUTATCN f'I..AM SHEETS IIDmlDIIUUtM.ltlDCll.A 2/2013 ~~~ • f5) ,.;;;-;:---l'LANlNl TABLES AK, NaTES 2006-16 -~ -u u '1\W 'f~© I ij ! SI I li : Bl I ~ fl e !,! ~ t I I 0 ~ ~ ~ ' u ! ,~ i ~ I I ! f " § .... ~ .... 6 1) 0 §~ ::, -· 0 c3 ..... /' . / / ' ' ' STATE OF WASHINGTON, COUNTY OF KING } . AFFIDAVIT OF PUBLICATION PUBLIC NOTICE Linda M Mills, being first duly sworn on oath that she is the Legal . Advertising Representative of the Renton Reporter ,. 'f"tekly newspaper, which newspaper is a legal newspaper of neral circulation and is now and has been for more than six months prior to the date of publication hereinafter referred to, published in the English language continuously as a weekly newspaper in King County, Washington. The Renton Reporter has been approved as a Legal Newspaper by order of the Superior Court of the State of Washington for King County: The notice in the exact form annexed was published in regular issues of the Renton Reporter (and not in supplement form) which was regularly distributed to its subscribers during the below stated period. The annexed notice, a: lP'ublic Notice was published on April 5, 2013. The full amount of the fee charged for said foregoing publication is $98.0b. • ,t.if I )/1 ;rt~ "Inda M. Mills Legal Advertising Representative, Renton Reporter Subscribed and sworn to me this 5th day of April, 2013. @'f--U.u,,__ {! ~IUA-,__ Kathleen C. Sherman, Notary Public for the State of Washington, Residing in Buckley, Washington ,,,,\\\\\\\\~u,,, .$-'' ~l'I C. S1t, ,,,,, ~ w<i:). :,,.'''""\\"111 ~-"' ,,, E ~~ ... ~s\ON ~~',,~ ~\. ::.<:r::~~ o"fA,;, ~''>' ~ tJc:o ~ J-~z ~ ~ ~o -• -en~ :: ~ ~ E ~ ~1-:,<> c,~~ ~ <.P~ lla\..\ .: < E ~ :..>,.4 ,._ -=-o -1,..,., ,,,, <l~19p\'-' ~~" .:: '/ T _>.. 111 ,,, 0 - 11/ ~ IIJ\\\\\"'-'' ~ .:;:- l//111 O,: WAS°"'\ ,,"'"' 1,, ,I\\\\\\"'''"'''' 1'0TICE OF PUBLIC II EARING RENTON HEARING EXAMINER RE;'li'TON, WASHl:\'GTOX A public Hearing will be held by the Renton Hearing Examiner in the Council Chambers on the seventh floor of Renton Citv Ha!L 1055 South Grady Wa)·. Renton. Washington.on Tuesday. April 16, 2013 at 1:00 pm to consider the following petitions May Creek Drainage Improvement Project LUAIJ-000187. SP. V-H Location: West side of 148th Ave SE just south of its inter- section with SE May Valley Rd. King County requests a Special Permit for Grade/Fill & Critical Areas Variance to improve in- stream !low conditions for May Creek between River Mile 4.3 & 4.9. Work within Renton would consist of removal of about 392 c.v. of accumulated sediment froffi 162 Lr of the May Creek Channel, as well as removal of obstructive vegeta- tion (reed canary grass & willow branches) from 540 1.f. of river channel. Proposed mit- igation includes 15 lcet of ri- parian/wet! and vegetation planted on both sides of May Creek. Legal descriptions of the files noted above are on fik in the City Clerk's Office, Seventh Floor. Citv llalL Renton. All interested · persons are invited to be present at the Public Hearing to express their opinions. Published in the Renton Reporter on April 5. 2013. #763687. Denis Law . Mayor <May 22, 2013. · Doug Chin Department of Community and_ Economic Development {.E."Chip"Vincent,Administrator. King County Water and Land Resources Division . 201 S Jackson Street, S~ite 600. · · Seattle, WA 98104 ·_SUBJECT: . . May CreekDrainage lmpr~vernentProject. . ' . . . LUAB-000187, V-H, SP . · Next Steps: Stream and Wetland Mitigation and Monitoring Plan Dear Mr. Chin: . · At this time, the Mitigation and Mainten·ance and Monitoring proposal has . be~n. approved by the City of .Renton:· Please see below for a detailed list of the ·remaining steps in the wetland mitigation/monitoring process: .. · Next Step: Because King County is a public agency, we ;ill not require collection of surety devices for the installatio_n of the mitigation planting or the mitigation . monitoring; However, we will require thi reporting as specified in the Renton Municipal Code for maintenance -~onitoring which includes quarterly reports for the first year and annually thereafter for four additional ~ears-provided thafthe mitigation is performing .. · as stated in the Stream and Wetland Impact Analysis and Mitigation Plan, prepared by · . King Cou~ty Road Services Division, Revised September 201L . Step Two: After instaliation of the mitigation is complete, please have your biologist SU bmjt a let_ter verifying that tl,e mitigation installation COlllplies With the app[OVed · : ·Stream and Wetland Impact Analysis and Mitigation Plan: -If any portion of the installed mitigation is·differerit from the approved plan,. please have your biologist submit an''.as built" plan set with the compliance letter and a biological justification for th_e changes to the approved plan. . . Step Three: The date the City receives w~itte~ confirmation from the biologist, the ·minimum s~year maintenance and monitoring ·period.will begin. If you have any questions, please cont~ctme at (425)430-~314. ?f ,4_~-I-_.,,, .---,;n. ··~.. • V.t· ~~-I. . . . ': -· . Associate Planner Renton City H·all_ • 1055 So~th Gi'ady W~y -. '.RentOn, Was_hingto~ 98057 · • re~t~nwa:g·q~ _ \ \ May Creek Drainage,lmpr_over LUA13°000187 Page 2 of2 cc: Stonegate HOA,:H~ppy Longfellow; Presiden(/Owne'r . Dale Koler/Party of Record . . Herbert Scheda/Party of Record Mary Celigoy/Partyqf Record ' ' • • . Denis Law Mayor May 1, 2013 Doug Chin · . KC Water & Land Resour.ces · 201 5. Jackson St. #600. Seattle; WA 98104 · City Cler~ -BonnieL Walton Re: Final Dedsion for May Cree.k Dra.inag~ Improvement Project. LUA-13~000187, SP, V-H . ·· Dear Mr. Chin: / Attached is your copy of the ·Hearing Examiner's Final Decision dated April 30, 2013, in the above-referen~ed matter. · ·· · · · · · · · · · · lfl can provide further information, please· feel free to contact me. · . Sincerely, Bonnie I: Walton City Clerk_ . Enc.:·. Hearing Examiner's Decision cc: · Hearing Examiner . . . . Gerald Wasser, Associate Planner Jennifer Henning,.Current Planning Manager Neil Wahs, Development Service Director Stacy.Tucker, Development Services . Parties of Record (4) 1055 South Grady Way • Renton: Washington 98057 • _(425) 43_o-6510 / Fax (425) 430-6516 • rentonwa.gov . ' Easy Peil Lab~! • · • ~ Use ~,y® TEMPLATE 5160® 6','.] I I:. = See Instruction Sheet I ~ rm;:\. 1 A Feed Paper = f(?r.Easy Peel Feature A ~.AVIEIJlV®5150® l Doug Chin KC Water & Land Resources 201 S. Jackson St. #600 Seattle, WA 98104 Dale Koler 16614 SE Renton/Issaquah Rd. Renton, WA 98055 I ttlquettes faclles a peler ~\ Utilisez le gabarit AVERy@ 5160® Stonegate HOA Mary Celigoy Happy Longfellow, President 10736 1541 h Place .SE 5404 NE 24 1h Ct Renton, WA 98059 Renton, WA 98059 Herbert Scheda 11115 Renton/Issaquah Rd. Issaquah, WA 98027 "' Sens de chargement Consultez la feullle d'instruction www.avery.com 1-800-GO-AVERY 2 3 4 5 6 7 8 9 JO 11 12 13 14 15 BEFORE THE HEARING EXAMINER FOR THE CITY OF RENTON RE: May Creek Drainage Improvement Project Special Grade/Fill Permit and CAO Variance LUAl3-000187, V-H, SP ) ) ) FINAL DECISION ) ) ) ) ) ) Summary 16 King County has applied for a Special Permit for Grade/Fill and a variance to critical ar.ea ordinance ("CAO") regulations for a dredging project to May Creek designed to reduce the duration of one year flood events for upstream properties. The permits are approved and the expiration date for the grade and fill permit is extended to eighteen months. 17 18 19 20 21 22 23 24 25 26 1' estimony Jennifer Henning, Renton Planning Manager, stated the application is for a special grading and fill permit and for a variance from the critical areas regulations. The site is within both the city of Renton and unincorporated King County. This hearing is for the section of the site within Renton. The site is zoned for one dwelling unit per acre, the city's lowest density for residential uses. The site is 3.75 acres, but the area within the city, subject to the application, is .84 acres. May Creek, a class 2 stream, bisects the site. In addition, there is a regulated flood plain, a wetland, and a greens creek which bisects the site from north to south. This project will result in dredging within May Creek, and invasive vegetation will be removed to improve the backwater effect and localized flooding. The actual work will remove 392 cubic yards of material over 160ft of May Creek. In order to accomplish the work, a bypass channel will be constructed to divert the creek water. Best SPECIAL GRADE/FILL PERMIT AND CAO VARIANCE -I 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 management practices will be utilized to prevent turbidity and keep the water quality high. In the end, large wood debris would be placed in the work area and vegetative material would be added. A split-rail fence will be installed at the approved buffers. The work would be limited to the approved fish windows as dictated by the Department of Fish and Wildlife as part of the hydraulic permit. This fish window is from June 16th to September 15th. Ms. Henning testified that Renton is requiring a special permit for grade and fill because of the public and agency interests in the project. In regard to the critical areas variance, there may be some exemptions within Renton code, particularly in regard to invasive species and enhancement of the area. There are a number of agency permits required, but most of them have already been issued. King County conducted a SEPA environmental review in September, 2010. A determination of non-significance mitigated which included five mitigation measures was subsequently issued. According to Ms. Henning, previously, the planned fencing was barbed wire; however, the applicant addressed concerns from the city and changed the fencing to split-rail. Once the sediment is removed from May Creek, it will be hauled across 148th Ave to deposition areas on the King County side of the project. The sediment will be dried out and then reused onsite. The sediment will not be put on any flood plains. The work will begin in summer 2013 or 2014, depending on the length of the permit process, and will be conducted Monday-Friday, 7am-7pm. Renton will allow some work on Saturdays if needed, but no work on Sundays. Renton does not require screening or fencing for this type of project, but the applicant is proposing a split-rail fence. There will be temporary noise and dust disturbances. The noise will be short-term. The applicant is addressing concerns about dust movement by creating rocked entrances on-and-off the site for vehicles. Additionally, the applicant will use methods such as watering-down to keep the dust manageable. In terms of impacts to surface water, the applicant will utilize sediment and erosion control measures. These measures include silt fences, core logs, and scheduling the work during low-flow periods. Equipment would not be in-stream. The work will occur in sections of 100-500ft lengths. Copper dams and sump pumps will be used to ensure water quality is acceptable prior to reintroducing water flow to the channel. . Ms. Henning added that Renton does not anticipate the project will result in a different use of the site, and the permit will transfer with the property. They are extending the dates of the permit beyond 6 months because of the fishing period limitations. In regard to the critical areas variance, city staff found that the flooding will be decreased which will improve welfare. Previous concerns regarding bank erosion have been alleviated by the current proposal. The project conforms to the city's comprehensive plan. King County looked at four other alternatives to meet the needs of the flooding problems; however, these alternatives were not feasible. Construction equipment will use existing roads and will have rubber tires. Disturbed areas will be resorted. Water work will be conducted during low flow periods in the summer. No net loss of area, function, or value will occur in the wetland or stream. 5-years of monitoring will occur once the project is completed. The project may affect, but is not likely to adversely affect, certain trout and salmon types. This variance is the minimum needed to accomplish the applicant's purpose. Best available science was used in preparing the reports for this project. Exhibit 7 illustrates the sediment that will be removed. SPECIAL GRADE/FILL PERMIT AND CAO VARIANCE -2 2 3 4 5 6 7 8 9 10 I I 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 Exhibit 8 is the landscape plan and shows where the reed canary grass will be removed. Staff is recommending approval of the permit and variances with two conditions of approval. The extension period for the grade-and-fill permit expiration is 1.5 years. Applicant Testimony Doug Chin, Project Manager, stated that on October 18, November 14, and November 15, 2011, King County held meetings with the Department of Ecology. On February 9, 2012, King County provided documentation in response to Dr. Patricia Olson's August 15, 2011 memorandum (exhibit 24d). The documentation clarified the benefits of the project along with information on post-project changes on flow durations and frequencies. In addition, King County provided information about sediment transport to Lake Washington, backwater effect at the creek foot bridge, methods for assessing sediment transport, data from ongoing downstream properties. On April 2, 2012, a field meeting was held with agencies and the downstream property owners. At this meeting, Patricia Olson represented the Department of Ecology. On May 22, 2012, an analysis by Dr. Olson (exhibit 24g) stated that the May Creek project would not likely create an increase in bank erosion. On June 14, 2012, the DOE sent a letter to King County (exhibit 24h) which confirmed that King County properly addressed all of the DOE's previous concerns regarding the project. On August 1, 2012, an analysis by King County staff ( exhibit 24i) found that the values used by Dr. Olson were reasonable. On November 14, 2012, King County Department of Permitting issued a clearing and grading permit for the project. Exhibit 25 is a DOE issued water quality certification for the project. No design changes have resulted from the additional analysis. In regard to _the Muckleshoot Indian Tribe concerns over mitigation measures for habitat impacts, King County is proposing additional measures over habitat impacts in the valley in the form of payment to a Tribe program. This mitigation measure has preliminary been determined to be acceptable. King County is currently working on the documentation to formalize the proposal. Mr. Chin submitted the flood hazard certification as exhibit 37. In conclusion, King County requests approval of the permit and vanance. Exhibits Exhibits 1-36 identified in a revised April 15, 2013 exhibit list submitted by Jennifer Henning were all admitted into the record during the 4/16/13 hearing. In addition, a flood hazard certification for the project was admitted as Exhibit 37 during the hearing. FlINJDJ[NG§ OJF lFAC'f l. Applicant. King County Water and Land Resources Division 2. Hearing. A hearing was held on April 16, 2013 at I :00 pm at the Renton City Hall City Council Meeting Chambers. SPECIAL GRADE/FILL PERMIT AND CAO VARIANCE -3 2 3 4 5 6 7 8 9 10 II 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 Substantive: 3. Description of Proposal. King County requests a Special Permit for Grade/Fill in order to improve in-stream flow conditions along the reach of May Creek between approximate river mile ("RM") 4.3 and 4.9. The project would result in the removal of approximately 392 cubic yards of accumulated sediment from approximately 162 lineal feet of the May Creek Channel, and the removal of obstructive vegetation (reed canary grass and willow branches) for approximately 540 lineal feet of river channel. The project is located in May Valley on the south side of SE May Valley Road near the cities of Newcastle and Renton. The project within Renton would occur on a parcel that is approximately 3.75 acres. The project site contains a Category 3 wetland and a Class 2 salmonid stream (May Creek). The Category 3 wetland is about l 40 acres in size and about 25 acres of the wetland is located in the project area. Work proposed for the wetland area appears to be limited to the construction of temporary access roads and the removal of canary grass and willow trees. As mitigation for removing sediment and vegetation, 15 feet of riparian/wetland vegetation would be planted on both sides of May Creek, and also outside City limits. Enhancement would include approximately 0.24 acres of off-channel alcoves, reed canary grass suppression, planting with native vegetation and large woody debris placement. All dredged materials will be deposited on site, eliminating the need for truck export. Additional vehicular access during project installation within the wetland and floodplain will be provided using rubber tired or tracked equipment. SEPA environmental review was conducted by King County as lead agency. The applicant also requests a variance to RMC 4-3-050(E)(2), which prohibits the disturbance of critical areas or their buffers. The applicant cannot avoid violating this provision because the proposal involves the dredging of May Creek and the removal and introduction of plant species to the creek and associated wetland. 4. Adverse Impacts. There are no significant adverse impacts associated with the proposal. The only impacts of concern are erosion/flooding impacts to downstream. properties and adverse environmental impacts to May Creek and its category 3 wetland. Although compatibility with adjoining uses has not been raised as an issue in the record, it is germane to the conditions of approval and is addressed below as well. A. Erosion/Flooding Impacts. As to erosion/flooding impacts, the proposal was denied in 2012 due to what the hearing examiner determined to be unresolved questions regarding impacts to downstream properties. Downstream property owners presented a memo from Dr. Patricia Olson, a hydraulic scientist from the Washington State Department of Ecology. In her memo Dr. Olson cited numerous flaws in the hydraulic studies prepared for the project, stating that the analysis may under-represent the amount of sediment transport ( and hence potential for erosion and flooding) created by the proposal. The applicant was given an opportunity to rebut the concerns expressed by Dr. Olson in her memo, but the examiner still concluded that the applicant had not sufficiently addressed SPECIAL GRADE/FILL PERMIT AND CAO VARIAN CE -4 I 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 B. all the problems raised by Dr. Olson. The proposal was denied without prejudice and the applicant was invited to reapply if they could satisfactorily resolve the concerns raised by Dr. Olson, or successfully submit their studies to third party peer review. Since denial, the applicant has worked with the Department of Ecology and Dr. Olson to address her concerns. Dr. Olson has now taken the position that the hydraulic studies and modeling done by the applicant were appropriate and that from those studies she is able to conclude that "the May Creek project will not likely create a measurable increase in bank erosion." See Ex. 24(0), p. I. Given that there is now no evidence or reasonable inferences to contradict Dr. Olson's conclusions on bank erosion, it must be determined that the proposal will not create any downstream erosion or otherwise adversely affect downstream properties. Critical Areas. · As to impacts to May Creek and its wetland, those impacts have been thoroughly assessed and completely mitigated in the Stream and Wetland Impact Analysis and Mitigation Plan, Ex. 13. The report, written by two environmental engineers, concludes that the proposal would achieve no net loss in of habitat functions in the May Creek sub-basin. This would be accomplished by enhancing approximately five acres of riparian buffer and riverine wetland. The enhancements would include planting native riparian/wetland vegetation, reed canary grass suppression, construction of two off- channel alcoves, placement oflarge woody-debris (76 pieces), and installation of snags in the wetland. Impacts to the wetland caused by the construction of temporary access roads and removal of canary reed grass and willow trees are considered only temporary and no permanent impacts are anticipated. The proposed vegetation removal in the stream would degrade riparian habitat by reducing canopy cover, organic inputs, prey sources, bank stability and future large wood recruitment. The enhancements and mitigation recommended in the Ex. 13 plan are designed to more than compensate for these adverse impacts. A biological evaluation for the proposal has evaluated impacts to any protected species that may be adversely affected by the proposal. See Ex. 20. The report concludes that the proposal will adversely affect essential fish habitat for coho salmon, but that the proposed mitigation and best management practices will limit the scope and scale of the impacts, and no large-scale deleterious effects are expected to occur. Further, it appears that the adverse impacts to the fish habitat will only be temporary as a direct result of the dredging activities and that the habit functions will improve over current conditions over time. For these reasons, it is concluded that the proposal will not have a significant adverse impact on protected species or their habitat. The proposal will also not adversely affect water quality. The water quality of the stream will be protected by diverting the stream from the dredging area· during dredging operations. All in-stream work is also only proposed during summer low flow periods (June 15 to September 15). Best management practices, including silt fences and coir logs, will be implemented to prevent sediment-laden stormwater from entering the stream SPECIAL GRADE/FILL PERMIT AND CAO VARIANCE -5- 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 or wetland. Best management practices will also be employed to ensure that groundwater water quality is not adversely affected. Construction and post-construction monitoring of surface water and ground water impacts will be conducted as described in Section 6.2 of the Stream and Wetland Impact Analysis and Mitigation Plan, Ex. 13 as well as the Post- Construction Monitoring Plan, Ex. 22. C. Compatibility with Adjoining Uses. The construction acttv1t1es associated with the proposal do not appear to create any compatibility problems with other properties in the vicinity, but as discussed below there is limited infonnation on these impacts. Compatibility concerns are reduced to a certain extent by virtue of the fact that there are few residences close to the project. The aerial photographs of Exhibits 35 and 36 reveal that much of the surrounding area is vacant, except for a handful of homes to the north, east and west and a more densely developed subdivision to the south along NE 26th St. The greatest area of concern on compatibility is truck traffic. 392 cubic yards of sediment will be dredged from May Creek and then hauled to other portions of the project site or on a King County site east of 148th Ave SE. Trucks and other equipment will be needed to move the sediment as well as to haul to and from the site for purposes of removing invasive species and introducing native species of plants. There does not appear to be any information in the record on how many truck trips would be generated by trus work. The staff report notes that trucks would access the site from 148th Ave SE. . th A large number of truck trips along 148 Ave SE could adversely affect the few homes abutting 148th Ave SE to the south of the project area. Given that 392 cubic yards is not an exceptionally large amount of fill, from the limited information in the record the best that can be concluded is that the proposal will not generate a significant amount of truck traffic that will adversely affect neighboring homes. The staff report also notes that some of the equipment on-site will generate noise up to 90 decibels. These noise levels could adversely affect neighboring properties, but the City has extensive noise standards that set a legislative standard on acceptable noise levels for all construction projects. See Chapter 8-7 RMC. No screening, fencing, landscaping or fencing are required for the proposal and none is necessary because there is notrung to suggest that the proposal will create any adverse aesthetic impacts except for the presence of construction equipment for a limited period of time between June 15 through September-15. There is little potential for dust generation since the sediment will be moist, but best management practices are proposed to control any remaining dust impacts. Gravel construction entrances to the project site are also proposed to prevent the tracking of dirt and dust onto local streets. No drainage problems at the project site (as opposed to downstream, which is addressed in FOF No. 5(A)) are evident from the record and none could be reasonably inferred. SPECIAL GRADE/FILL PERMIT AND CAO VARIAN CE -6 2 3 4 5 6 7 8 9 10 I I 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 Conclusions of lLaw Procedural: I. Authority of Hearing Examiner. RMC f-9-080(F)(2) provides that the hearing examiner is responsible for granting special permits for fill and grade. The code section provides that a special permit is required for the depositing of minerals or materials such as sand, gravel and rock. The proposed dredging will involve the depositing of dredged materials on site, so a special use permit is required and subject to review by the Examiner. RMC 4-8-080(0) also classifies variances associated with hearing examiner land use review as Type III permits subject to hearing examiner review. As further noted in RMC 4-8-080(0), the hearing examiner is required to make a final decision on both the special grade and fill permit and the variance request and both decisions are appeal able to the City Council. Substantive: 2. Applicable Standards. RMC 4-9-080(F)(4) governs the criteria for special fill/grade permits. RMC 4-9-250(B)(l 0) governs the criteria for the CAO variance. Applicable criteria are quoted below in italics and applied through corresponding conclusions of law. RMC 4-9-080(F)(4): ... To grant a special permit, the Hearing Examiner shall make a determination that .. the proposed activity would not be unreasonably detrimental to the surrounding area. The Hearing Examiner shall consider. but is not limited to, the following: i. Size and location of the activity. ii. Traffic volume and patterns. iii. Screening, landscaping, fencing and setbacks. iv. Unsightliness, noise and dust. v. Surface drainage. vi. The length of time the application ofan existing operation has to comply with nonsafety provisions of this Title. 3. As noted in the criterion above, the six factors. listed above are designed to assist the hearing examiner in determining whether or not the proposed clearing and grading "would not be unreasonably detrimental to the surrounding area." From this language it appears that the primary issue of concern would usually be truck traffic, noise, dust and other adverse impacts · generated by major clearing and grading operations. It is evident that convoys of trucks were SPECIAL GRADE/FILL PERMIT AND CAO VARIAN CE -7 I 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 envisioned navigating through neighborhood streets. Yet all of the extensive information in the record focuses almost exclusively upon downstream erosion and critical area impacts. Downstream erosion impacts are certainly relevant to the issue of impacts to the surrounding area and are addressed in Finding of Fact No. 5(A). However, the record has been lacking on the afore- mentioned truck traffic, dust, and noise impacts. There is apparently no estimate provided on the number of truck trips that will be generated by the proposed dredging operations. However, from the limited information in the record it has been determined in Finding of Fact No. 4(C) that the proposal will not adversely affect properties in the surrounding area considering all of the factors listed in the criterion above. Further, as determined in Finding of Fact No. 4(A), the proposal will also not adversely affect downstream properties with erosion impacts and as detennined in Finding of Fact No. 4(B) the proposal will not adversely affect May Creek or on-site wetlands. As to the length of time of the application, RMC 4-9-080(F)(l 0) requires that work commence with six months of approval. Staff recommends that this be extended to 1.5 years because the applicant can only do the work during low summer flows. For this reason, the expiration date set by RMC 4- 9-080(F)(l 0) is extended from six months to 1.5 years. RMC 4-9-250(8)(10)(a): ... in lieu of the variance criteria of subsection B5 of this Section, applications for public/quasi-public utilities or agencies proposing to alter aquifer protection, geologic hazard, habit, stream and lake or wetland regulations shall be reviewed for compliance with all of the following criteria: a. Public policies have been evaluated and it has been determined by the Department Administrator that the public's health, safety and welfare is best served; 4. The proposal is designed to reduce flooding caused by May Creek and as determined in Finding of Fact No. 4 there are no significant adverse impacts as mitigated. For these reasons the· public health, safety and welfare is served by the proposed variance. RMC 4-9-250(B)(IO)(b): Each facility must conform to the Comprehensive Land Use Plan and with any adopted public programs and policies; 5. The proposal is consistent with and implements Comprehensive Plan policies EN-2 and EN-4 by minimizing erosion impacts and naturalizing a degraded stream. RMC 4-9-250(8)(10)(c): Each facility must serve established, identified public needs; 6. The proposal is designed to prevent what has proven to be repeated flooding of residential and agricultural properties. RCW 4-9-250(B)(IO)(d): No practical alternative exists to meet the needs; SPECIAL GRADE/FILL PERMIT AND CAO VARIAN CE -8 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 7. As identified in the staff report, the proposal is the alternative that will cause the least disturbance to critical areas while still reducing the flood reduction objectives of the proposal and remaining financially feasible. RMC 4-9-250(B)(IO)(e): The proposed action takes affirmative and appropriate measures to minimize and compensate for unavoidable impacts; 8. As determined in Finding of Fact No. 4(B), all impacts have been fully mitigated. RMC 4-9-250(B)(IO)(f): The proposed activity results in no net loss of regulated wetland or stream/lake area, value, or fimction in the drainage basin where the wetland, stream or lake is located; 9. As determined in Finding of Fact No. 4(B), the proposal results in no net loss in wetland or stream habitat functions. The proposal will also improve upon the flood reduction function of streams and wetlands. RMC 4-9-250(B)(IO)(g): The proposed activities will not jeopardize the continued existence of endangered. threatened or sensitive species as listed by the Federal government or the State; 10. As determined in Finding of Fact No. 4(B), the proposal will have any significant adverse impacts on any protected species. RMC 4-9-250(B)(IO)(h): That the proposed activities will not cause significant degradation of groundwater or swface water quality; 11. As determined in Finding of Fact No. 4(B), the proposal will not adversely affect groundwater or surface water quality. RMC 4-9-250(B)(IO)(i): The approval is the minimum variance necessary to accomplish the desired purpose; 12. The applicant maintains that no further reduction in critical area disturbance can be achieved without compromising the flood reduction objectives of the proposal and there is nothing in the record to suggest otherwise. RMC 4-9-250(B)(10)(j): The proposed variance is based on consideration of the best available science as described in WAC 365-195-905; or where there is an absence of valid scientific information, the steps in RMC 4-9-250F are followed. 13. The proposal clearly employs best available science. The proposal has been subjected to an impressive number of scientific studies prepared by qualified experts. These studies, in SPECIAL GRADE/FILL PERMIT AND CAO VARIAN CE -9 I 2 3 4 5 6 7 8 9 10 11 12 particular the sediment transport studies, have been subject to rigorous peer review by DOE and subjected to close public scrutiny as well. DJEC][S][ON The applications for a Special Permit for Grade and Fill and a CAO Variance from RMC 4-3- 050E.2 for the May Creek Drainage Improvement Project; Project File No. LUA I 0-065, V-H, SP, are approved subject to the following conditions: 1. Compliance with the mitigation measures contained in the Mitigated Determination of Non-Significance, issued by the King County Water and Land Resources Division, Department of Natural Resources and Parks, dated September 8, 2011 (Exhibit 12). 2. The applicant shall comply with the Stream and Wetland Impact Analysis and Mitigation Plan (Exhibit 13, Revised September 2011) throughout and following construction. 3. The applicant shall comply with the Post-Construction Erosion Monitoring Plan, Ex. 22. The expiration period for the Special Permit for Grade and Fill is extended from six months to 18 13 months as regulated in RMC 4-9-080(F)(l 0). 14 15 16 17 18 19 20 21 22 23 24 25 26 DATED this 30th day of April, 2013. City of Renton Hearing Examiner A]Ppeal lRight and! Valuation Notices RMC 4-8-l lO(E)(9) and/or RMC 4-8-1 lO(F)(l) provides that the final decision of the hearing examiner is final subject to appeal to the Renton City Council. RMC 4-8-l lO(E)(9) requires appeals of the hearing examiner's decision to be filed within fourteen (14) calendar days from the date of the hearing examiner's decision. A request for reconsideration to the hearing e examiner may also be filed within this 14 day appeal period as identified in RMC 4-8-11 O(E)(8) and RMC 4- 8-IOO(G)(4). A new fourteen (14) day appeal period shall commence upon the issuance of the SPECIAL GRADE/FILL PERMIT AND CAO VARIANCE -I 0 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 reconsideration. Additional information regarding the appeal process may be obtained from the City Clerk's Office, Renton City Hall-7th floor, (425) 430-6510. Affected property owners may request a change in valuation for property tax purposes notwithstanding any program of revaluation. SPECIAL GRADE/FILL PERMIT AND CAO VARIANCE -11 RECEIPT EG00007368 BILLING CONTACT Doug Chin King County Water & Land Resources Division 201 S Jackson St , Suite 600 Seattle, WA 98104 . Transaction Date: April 24, 2013 ----------------·----· ------------------------ REFERENCE NUMBER FEE NAME ILUA13-000187 I Technology Fee Printed On: 4/24/2013 Prepared By: Holly Powers TRANSACTION TYPE I Fee Payment PAYMENT METHOD jcredit Card SUB TOTAL TOTAL AMOUNT PAID $60.00 $60.00 '-------' $60.00 Page 1 of 1 ' CITY OF RENTON D1EPARTMEN1' OF COMMUNITY & ECONOMIC DEVELOPMENT MEMORANDUM Date: April 11, 2013 To: City Clerk's Office From: Stacy M Tucker Subject: Land Use File Closeout Please complete the following information to facilitate project closeout and indexing by the City Clerk's Office. -_----.----. ·-· ------.-c_ --•------c-------------~---=--~---~'1 Project Name: May Creek Drainage Improvement Project I LUA~000187, SP, V-H :: LUA (file) Number: ,; Cross-References: •1 AKA's: !' Project Manager: Gerald Wasser ,1 !I Acceptance Date: March 21, 2013 1·1 ,··-------------------------------------' i: Applicant: Doug Chin, King County Water & Land Resources Division :: Owner: Happy Longfellow, Stonegate HOA; City of Renton ,. Contact: Same as applicant PID Number: 803540UINT ii ------------------------------------'! ERC Decision Date: ii ERC Appeal Date: ------------------------------------'' · Administrative Denial: 11 Appeal Period Ends: __;:..;_ ___________________________________ ! ., Public Hearing Date: April 16, 2013 Ir ,, Date Appealed to HEX: 1! By Whom: '! :I HEX Decision: Date: ____________________________________ I Date Appealed to Council: t'I By Whom: · Council Decision: Date: 'I · Mylar Recording Number: ij '· I · Project Description: Applicant requests Hearing Examiner approval for a Special Permit for 'I ·· Grade/Fill and a Critical Areas Variance in order to improve in-stream flow conditions along the , · reach of May Creek between approximate River Mile 4.3 and 4.9. , Location: West of 148th Avenue SE and south of May Valley Road ,, Comments: Ii I L·--=---=-=-=--=·-------:::....=----=--..:-=-~--:-= ~~ -__ :...::=_·:;::;::::~ ---------- r -=.c.. == =~-:=== _11 DEPARTMENT OF COMMUNITY AND ECONOMIC DEVELOPMENT ' HEARING EXAMINER PUBLIC HEARING April 16, 2013 AGENDA COMMENCING AT 1:00 PM COUNCIL CHAMBERS, 7TH FLOOR, RENTON CITY HALL The application(s) listed are in order of application number only and not necessarily the order in which they will be heard. Items will be called for hearing at the discretion of the Hearing Examiner. PROJECT NAME: May Creek Drainage Improvement Project PROJECT NUMBER: LUA13-000187, SP, V-H PROJECT DESCRIPTION: Applicant requests a Special Permit for Grade/Fill in order to improve in-stream flow conditions along the reach of May Creek between river mile 4.3 and 4.9. The proposal also requires a Critical Areas Variance from RMC 4-3-050.E in order to alter a stream and wetland and accomplish the sediment removal work. The project would result in the removal of 392 cubic yards of accumulated sediment from about 162 linear feet of the May Creek Channel within Renton, and the removal of obstructive vegetation (reed canary grass and willow branches) from approximately 540 lineal feet of river channel. HEX Agenda 04-16-13.doc DEPARTMENT OF COMI\. . ..,NITY AND ECONOMIC DEVELOPMENT PRELIMINARY REPORT TO THE HEARING E)(AMINER PUBLIC HEARING DATE: April 16, 2013 Project Name: Owner: Applicant /Contact: File Number: Project Manager: Project Summary: Project Location: Exist. Bldg. Area SF: Site Area: May Creek Drainage Improvement Project Happy Longfellow, President Stonegate Homeowners Association 5405 NE 24th Court Renton, WA 98059 Doug Chin King County Water and Land Resources Division 201 South Jackson Street, Suite 600 Seattle, WA 98104 LUAB-000187, SP, V-H Gerald Wasser, Associate Planner Applicant requests a Special Permit for Grade/Fill in order to improve in- stream flow conditions along the reach of May Creek between river mile 4.3 and 4.9. The proposal also requires a Critical Areas Variance from RMC 4-3-050.E. in order to alter a stream and wetland and accomplish the sediment removal work. The project would result in the removal of 392 cubic yards of accumulated sediment from about 162 linear feet of the May Creek Channel within Renton, and the removal of obstructive vegetation (reed canary grass and willow branches) from approximately 540 lineal feet of river channel. The project is located in May Valley on the south side of SE May Valley Road near Newcastle and Renton and is within Renton and unincorporated King County. The work would occur on a parcel that is approximately 3. 75 acres within Renton. The project site contains a Category 3 wetland, and a Class 2 salmonid stream (May Creek) and a Class 4 creek (commonly referred to as Green's Stream or Green Creek) and also a regulated floodplain. As mitigation for removing sediment and vegetation, 15 feet of riparian/wetland vegetation would be planted on both sides of May Creek, and habitat log structures and wildlife snags would be anchored within the stream buffer and alcoves. The project is expected to commence during the first approved fish window after receiving the permit, likely in summer 2013. SEPA Environmental Review was conducted by King County as the lead agency and issued on September 8, 2010. West of 148th Avenue SE and south of May Valley Road None Proposed New Bldg. Area (footprint): N/ A 3.75 ac Total Building Area GSF: None I l. City of Renton Department of Corr 1ity & Economic Development Pr ;nary Report to the Hearing Examiner MAY CREEK DRAINAGE IMPROVEi. __ ,vT PROJECT LUA13-000187, V-H, SP Hearing Date: April 16, 2013 Page 2 of 14 I A. EXHIBITS: Exhibit 1: Exhibit 2: Exhibit 3: Exhibit 4: Exhibit 5: Exhibit 6: Exhibit 7: Exhibit 8: Exhibit 9: Exhibit 10: Exhibit 11: Exhibit 12: Exhibit 13: Exhibit 14: Exhibit 15: Exhibit 16: Exhibit 17: Exhibit 18: Exhibit 19: Exhibit 20: Exhibit 21: Exhibit 22: Exhibit 23: Exhibit 24: HEX Report Staff Report, dated April 16, 2013 Aerial Photo, Showing Project Site Vicinity Map and Index {Sheet 1 of 20) Neighborhood Detail Map {Sheet 1 of 1) Topography Map {Sheet 1 of 1) Existing Conditions, Sheet Key, Legend, Construction Notes {Sheet 4 of 20) Site Plan {Sheet 1 of 1) Landscaping Plan {Sheet 1 of 1) Temporary Erosion and Sediment Control Plan, Legend {Sheet 5 of 20) Sediment Disposal and Turbid Water Dispersion Locations (Sheet 7 of 20) Plan and Profile, STA 0+00 to STA8+00 (Sheet 10 of 20) King County Mitigated Determination of Non-Significance {Issue Date September 8, 2010) Stream and Wetland Impact Analysis and Mitigation Plan {King County Road Services Division and King County Water and Land Resources Division, Revised September 2011) Wetland Delineation Report {Kirig County Road Services Division, Environmental Unit) March 10, 2010 City of Renton Wetland Rating Addendum to Wetland Delineation Report Dated March 10, 2010 (November 17, 2010) Baseline Stream Conditions (Revised December 2, 2010} May Creek Sediment Transport Study Report {Anchor QEA, LLC, June 2009) May Creek Erosion Stabilization Draft Report/May Creek Sediment Transport Study Phase 3 (Anchor QEA, LLC, January 2010) Hydraulic And Hydrologic Analysis {King County Department of Natural Resources and Parks, Water and Land Resources Division, Science Section, December 17, 2010) Biological Evaluation Report for: Chinook Salmon and Steelhead Trout as protected under the Endangered Species Act {King County Road Services Division, February 2011) May Creek Drainage Improvement Project: SE May Valley Road and 148'h Avenue SE -Sediment Assessment (King County Road Services Division, Environmental Unit, February 9, 2011) May Creek Drainage Improvement Project (9A1205) Post-Construction Erosion Monitoring Plan -Downstream of 18'h Avenue SE {King County Road Services Division, Engineering Services Section, August 4, 2011) Construction Water Quality Protection and Monitoring Plan (King County, Revised September 7, 2011} Correspondence between the Department of Ecology and King County Including: o Internal DOE memo from Patricia Olson to Rebekah Padgett, August 15, 2011; City of Renton Deportment of Corr 1ity & Economic Development Pr inary Report to the Hearing Examiner MAY CREEK DRAINAGE IMPROVE, •. _NT PROJECT LUA13-000187, V-H, SP Hearing Date: April 16, 2013 Page 3 of 14 Exhibit 25: Exhibit 26: Exhibit 27: Exhibit 28: Exhibit 29: Exhibit 30: Exhibit 31: Exhibit 32: Exhibit 33: Exhibit 34: Exhibit 35: Exhibit 36: o Letter from Rebekah Padgett, DOE to Doug Chin, King County, September 16, 2011; o Letter from Doug Chin, King County to Rebekah Padgett, DOE, February 9, 2012; o Internal DOE memo from Patricia Olson to Rebekah Padgett, May 22, 2012; o Letter from Eric Stockdale, DOE to Doug Chin, King County, June 14, 2012. Washington Department of Ecology, Water Quality Certification Order #9352 for USACOE Public Notice #NWS-2010-158, January 8, 2013 King County Clearing and Grading Permit {LlOCG223), Issued November 14, 2012 NOAA/NMFS (Tracking No. 2011/00601) Endangered Species Act Section 7 Informal Consultation, March 10, 2011 WDFW Hydraulic Project Approval, (Control Number: 123184-2, September 26, 2011) Rehabilitation Plan: Wetland and Riparian Mitigation (Sheet 1 of 7) Rehabilitation Plan: Planting Tables and Notes {Sheet 6 of 7) LUAll-065 Hearing Examiner Final Decision {Issued November 8, 2011) LUAll-065 Hearing Examiner.Decision on Reconsideration {Issued January 9, 2012) Master Application Proof of Posting & Mailing Aerial Photo showing wetland, streams Aerial Photo showing regulated flood plain I 8. GENERALINFORMATION: 1. Owner(s) of Record: 2. Zoning Designation: 3. Comprehensive Plan Land Use Designation: 4. Existing Site Use: 5 .. Neighborhood Characteristics: Happy Longfellow, President Stonegate Homeowners Association 5405 NE 24th Court Renton,WA 98059 Residential 1 dwelling unit per acre (R-1) Residential Low Density {RLD) Vacant (stream and wetland area) North: Single-family residences and vacant (R-1 zone) East: Single-family residences and vacant (R-1 zone) South: Single-family residences and vacant (R-1 zone) West: Single-family residences and vacant (R-1 zone) 6. Access: 7. Site Area: HEX Report Temporary construction road off 148th Avenue SE 36,600 square feet within a 3.75 acre site City of Renton Deportment of Corr city & Economic Development Pr inary Report to the Hearing Examiner MAY CREEK DRAINAGE IMPROVt, .. _.VT PROJECT LUA13-000187, V-H, SP Hearing Date: April 16, 2013 Page 4 of 14 I c. HISTORICAL/BACKGROUND: Action Description Land Use File No. Ordinance Date No. May Creek Drainage Special Permit for Grade & LUA11-065 N/A 11/8/2011 Improvement Fill and Critical Areas Project -Denied Variance Without Prejudice Comprehensive Plan N/A N/A 5099 11/1/2004 Zoning N/A N/A 4404 6/7/1993 Annexation N/A N/A 4510 6/20/1966 ID. PUBLIC SERVICES: 1. Utilities: Not applicable. The proposed project is for drainage improvement in May Creek. 2. Streets: Access to the site will be ~ia rocked construction entrances from 1481h Ave SE, one north of May Creek, and one south of May Creek. Two rocked construction entrances from 1481h Ave SE would access the site to the east where work would occur within King County. A traffic control plan is necessary and must be submitted and approved prior to the start of construction for the entrances on 1481h Avenue SE. Construction hours will be in accordance with City standards (Monday-Friday 7:00 am -8:00 pm, Saturday 9:00 am -8:00 pm, and no work on Sundays). Haul routes are restricted to the hours of 8:30 am and 3:30 pm, Monday through Friday, or as established in the approved traffic control plan. All frontage streets are paved with curb and gutter. 3. Emergency Services: Provided per City of Renton Fire Department and Police Department for that portion within Renton. E. APPLICABLE SECTIONS OF THE RENTON MUNICIPAL CODE: 1. Chapter 2 Land Use Districts a. Section 4-2-020 Purpose and Intent of Zoning Districts b. Section 4-2-060 Zoning Use Table c. Section 4-2-110 Development Standards for Residential Zoning Designations 2. Chapter 3 Environmental Regulations and overlay Districts a. Section 4-3-050 Critical Areas Regulations 3. Chapter 4 City-wide Property Development Standards a. Section 4-4-060 Grading, Excavation and Mining Regulations 4. Chapter 8 Permits General and Appeals a. Section 4-8-080 Permit Classification HEX Report City of Renton Department of Corr oity & Economic Development Pr inary Report to the Hearing Examiner MAY CREEK DRAINAGE IMPROVE,. __ ,VT PROJECT WA13-000187, V-H, SP Hearing Date: April 16, 2013 Page 5 of 14 5. Chapter 9 Procedures and Review Criteria a. Section 4-9-080 Grading, Excavation, and Mining Permits and Licenses 6. Chapter 11 Definitions F. APPLICABLE SECTIONS OF THE COMPREHENSIVE PLAN: 1. Land Use Element: Residential Low Density Land Use Designation 2. Environmental Element Resource Land I G. DEPARTMENTANALYSIS: 1. Project Description/Background King County's Water and Land Resources Division proposes to improve in-stream flow conditions along segments of May Creek in May Valley between approximately river mile 4.3 and 4.9. Sediment accumulation and in-stream vegetation throughout the valley reach of May Creek have been gradually decreasing channel flow capacity, causing a backwater effect. This is increa_sing the duration of flooding in actively used pastures on adjacent rural residential properties with flood conditions now persisting into the summer months. The goal of this project is to reduce the duration of localized flooding on these properties at both start and end of the rainy season by removing in-stream channel obstructions. This is anticipated to alleviate the duration of localized flooding on adjacent properties during low to moderate storm events and should allow pastures to drain more effectively when flooding does occur. Due to the high groundwater table in May Valley and because there would be no measurable difference in the geographic extent of flooding, it is not likely that this project will change the amount of wet pasture or wetland in the project vicinity. The project hydraulic analysis found that the potential for erosion downstream of May Valley would be virtually unchanged for before and after project conditions. Within the City of Renton, the project proposes to remove accumulated sediment (approximately 392 cubic yards) from approximately 160 linear feet of the May Creek channel, and remove flow obstructing vegetation (such as reed canary grass and willow branches) from approximately 540 linear feet of channel. No trees greater than 6-inch diameter chest height would be removed. May Creek is a Class 2 (salmon id-bearing stream) and there is an associated Category 3 wetland which would be impacted by the proposed project. Additional sediment and vegetation removal will happen in May Creek outside the City boundary. As mitigation for removing sediment and vegetation, 15 feet of riparian/wetland vegetation would be planted on both sides of May Creek within and outside the City of Renton. Approximately 3 acres of riverine wetland would be enhanced. Enhancements would include approximately 0.24 acres of off-channel alcoves, reed canary grass suppression, planting with native vegetation, and large woody debris placement. Site access would be provided via a temporary construction road off 1481h Avenue NE. Additional access within the wetland and floodplain will be provided by using rubber tired or tracked equipment. This equipment can move over the landscape with minimal ground disturbance. This proposed project (LUAll-065) was originally heard by the City of Renton Hearing Examiner on October 4, 2011. The Hearing Examiner denied the project without prejudice on November 11, 2011 HEX Report City of Renton Department of Corr 1ity & Economic Development Pf' 'nary Report to the Hearing Examiner MAY CREEK DRAINAGE IMPROVE, •. _.~T PROJECT LUA13-000187, V-H, SP Hearing Date: April 16, 2013 Page 6 of 14 because there was insufficient evidence to conclude that the project would not adversely affect downstream properties. The applicant requested reconsideration of the decision and on January 9, 2012, the Hearing Examiner still denied the grade and fill permit and the critical areas variance without prejudice. The Hearing Examiner recommended that should King County re-apply, the City should hire an independent third party reviewer to assess the validity of the conclusions of King County. In the alternative, the Examiner allowed that evidence that King County has resolved the concerns of Dr. Patricia Olson would be equally persuasive. A number of public comments were received prior to the October 4, 2011 Hearing Examiner public hearing on LUAll-065; however, no public comments were received by the April 4, 2013 comment deadline for the current application. The project applicant has chosen to resolve the concerns of Dr. Patricia Olson (Department of Ecology). On May 22, 2012, Dr. Patricia Olson in a Department of Ecology internal memo (Exhibit 24) discussed the May Creek Drainage Improvement Project. She stated that bank erosion appears to be the greatest concern for the downstream property owners. Dr. Olson used the bank stability and toe erosion model {BSTEM) to evaluate bank erosion under pre-project and post-project high flow conditions. She concluded that the BSTEM model is adequate to evaluate different flow and duration scenarios. The results she found indicate that post-project flow and duration conditions may increase bank erosion by approximately 2 cm for the 1-year peak flow event and less for higher magnitude peak flow events. She stated that because this amount is within the model error, it may be meaningless. After field site observations, additional data which was supplied by King County (as requested by the Department of Ecology), and the BSTEM analysis, Dr. Olson concluded that the May Creek Drainage Improvement Project would not create a measurable increase in bank erosion. The Department of Ecology in a June 14, 2012 letter (Exhibit 24) from Erik Stockdale, Wetlands/401 Unit Supervisor to Doug Chin {King County Department of Natural Resources, Water and Land Resources Division) addresses various aspects of the proposed project: o Dr. Olson's analysis concludes that the project would not likely create a measurable increase in bank erosion downstream of the project site; o The Department of Ecology will accept the planting and fencing of a permanent 15-foot wide area on both banks of May Creek, as well as the Stonegate property wetland enhancement, as adequate mitigation for the stream and wetland impacts related to the dredging project; o When considered in context of Dr. Olson's additional analysis, King County has addressed the concerns of the Department of Ecology; and o · Department of Ecology does not have concerns about downstream flooding issues. It should be noted that public projects which result in dredging or placement of fill on lands covered by water, where state and federal permits are required to complete the activity are exempt from the requirements for Special Grade and Fill Permits. However, because this project required Environmental {SEPA) Review, and concern had been expressed by property owners in the vicinity, staff believes that requiring a Special Grade and Fill Permit is appropriate. A Critical Areas Variance is also required by public agencies proposing to alter habitat, streams and wetlands. HEX Report City of Renton Department of Corr -city & Economic Development MAY CREEK DRAINAGE IMPROVE, __ ,VT PROJECT Hearing Date: April 16, 2013 2. Environmental Review Pr inary Report to the Hearing Examiner LUA13-000187, V-H, SP Page 7 of 14 King County Water and Land Resources Division issued a Mitigated Determination of Non-Significance (DNS-M), dated September 8, 2010 for the May Creek Drainage Improvement Project (King County File No. 9A1205). That Mitigated Determination of Non-Significance (Exhibit 12) states that the following mitigation measures would be implemented to avoid, minimize, and compensate for negative impacts to the in-stream and wetland habitat. o During construction, the stream flow will be diverted around the work area, and in-water work will only be conducted during the summer low flow when fish are less likely to be present. A King County biologist will be onsite during construction to monitor water quality. o Construction techniques, such as utilizing existing access roads or using temporary steel plates (or equivalent), where additional access is needed, will minimize disturbances to existing vegetation. In addition, direct access to the stream channel by equipment will only be allowed in specific areas where vegetation disturbance can be minimized. o Approximately 1.3 acres of wetland and riparian vegetation will be planted along May Creek (15 feet on each side of the stream from 148th Avenue SE upstream to the end of the project). Fencing will be installed to protect the plantings and the stream from livestock. o Approximately 3.75 acres of wetland will be enhanced on the west side of 148th Avenue SE by removing invasive reed canary grass and replanting with native wetland vegetation. Off- channel alcoves will also be excavated along May Creek in this location and large woody debris and streambed gravel will be added in the alcoves to enhance wetland fish habitat. o Fish habitat and natural stream processes will be restored at either the confluence of Long Marsh Creek and May Creek, or at a similar location in the project vicinity. 3. Staff Review Comments Representatives from various City departments have reviewed the application materials to identify and address issues raised by the proposed development. These comments are contained in the official file, and the essence of the comments has been incorporated into the appropriate sections of this report and the Departmental Recommendation at the end of this report. 4. Consistency with Special Grade and Fill Permit Criteria In order to grant a special permit, the Hearing Examiner shall make a determination that the activity would not be unreasonably detrimental to the surrounding area. The Hearing Examiner shall consider, but not be limited to, the following: a) Size and Location of the Activity. The applicant is seeking approval of a Special Fill and Grade Permit to allow the dredging of sediment and in-stream vegetation in the May Creek channel. The project site within the City of Renton is located west of 148th Avenue SE and south of SE May Valley Road. It is estimated that approximately 392 cubic yards of sediment as well as flow obstructing vegetation would be removed. The portion of the project site within the City of Renton is approximately 36,600 square feet. Sediment would be HEX Report City of Renton Department of Corr ")ity & Economic Development MAY CREEK DRAINAGE IMPROVf,. __ NT PROJECT Hearing Date: April 16, 2013 Pr, 'nary Report to the Hearing Examiner LUA13-000187, V-H, SP Page 8 of 14 removed from the stream channel using low impact machinery operated from the stream bank. The stream would be diverted around the construction site ·to minimize temporary downstream water quality impacts. Sediment would be placed in onsite drying areas as shown in Exhibit 10 and then would be disposed of either on site or on the King County site on the east side of 148th Ave SE, outside flood prone and sensitive areas. b) Traffic Volumes and Patterns. Construction equipment would use existing roads whenever possible to cross wetlands, floodplain, and stream. Site access would be provided by two temporary construction entrances from 14gth Avenue SE. Additional access within the wetland and floodplain would be provided by using rubber tired or tracked equipment. Such equipment can move over the landscape with minimal ground disturbance. As described in Section 4.a), above, dredged sediment would be disposed of in sediment disposal areas as shown on Exhibit 10. c) Screening, Landscaping, Fencing and Setbacks. No screening, landscaping, fencing or setbacks are required in the City of Renton Development Standards for the dredging of May Creek. King County is proposing to fence the project area within the City of Renton with split rail fencing to protect the enhanced riparian and wetland habitat. Such fencing would also include signage which would identify the area as a sensitive area. The wetland enhancement includes off-channel alcoves which would partially replace some in-stream habitat functions lost due to sediment and vegetation removal. The wetland enhancement also includes the suppression of reed canary grass and replanting of native vegetation. The riparian buffer planting would improve long term buffer function by minimizing reed canary grass and replanting of native vegetation, and placement of large woody debris. d) Unsightliness, Noise, Dust. The project would be constructed in two phases. Sediment removal, vegetation removal, and mitigation construction would occur within the first approved fish window (June 16 to September 15) after receiving project approvals. Riparian and wetland plants would be installed during the following dormant season {November to February). During project construction there will be areas of disturbance. However, this is a temporary project and areas of disturbance will be restored and enhanced. During construction, equipment operation would temporarily increase noise_ levels in the vicinity. Construction equipment may produce temporary noise levels as high as 90 decibels. The completed project, however, would not change existing noise levels. The proposed project may generate some dust during the transport of soil and sediment to the sediment disposal areas and the turbid water dispersion locations on that portion of the project site across 148'h Ave SE to the east, and within King County. Because the material being transported would originate from the stream channel and wetland, it will likely be moist, and therefore will have little potential for generating dust. However, once dry, the material could general dust. Best Management Practices would be used to suppress dust. In addition, gravel construction entrances off of 148th Avenue SE will be in place to aid in tracking dirt and dust onto local streets. HEX Report City of Renton Department of Corr ,:iity & Economic Development Pr ;nary Report to the Hearing Examiner MAY CREEK DRAINAGE IMPROVE, .. _NT PROJECT LUA13-000l87, V-H, SP Hearing Date: April 16, 2013 Page 9 of 14 e) Surface Water During construction, erosion would be minimized by implementing appropriate sediment and erosion control best management practices. Measures would include a plan to divert flow from the stream reaches where the sediment and in-stream vegetation would be removed. Diverting the stream around the work area would minimize downstream water quality impacts. The plan would also limit all in-stream work to summer low flow periods. In areas where invasive vegetation is removed from stream banks and replanted with native vegetation, best management practices would be implemented, including silt fences and coir logs to prevent sediment-laden stormwater from entering the stream or wetland (Exhibit 9). According to notes contained on Exhibit 6, sediment removal will occur using machinery operated from the stream bank (Note 18). Sediment removal shall be done in the dry season, and sections worked will be 100 to 500 lineal feet in length starting at the upstream portion of the King County site and working downstream to the Renton site (Note 19). Prior to bypassing the stream, the engineer will schedule fish removal that the biologist will accomplish, and this will occur with at least 7 days notice (Note 19). Once sediment has been excavated, stream flow will be reintroduced to the channel under the direction of the engineer (Note 20). Cofferdams and sump pumps will be used to reintroduce flow to the new channel to ensure that water quality can be met. Flow would be introduced to the newly excavated channel, and turbid water will be pumped out at the downstream end of the construction area and discharged to the temporary water dispersion area until water flow through the channel meets state water quality standards. No temporary exceedances of state water quality standards would be allowed (Note 21). As stated previously, sediment would be placed in onsite drying areas and then would be disposed of onsite outside flood prone and sensitive areas. Such drying areas would be located south of the stream channel (Exhibit 10). Also, during the sediment and in-stream vegetation removal, the stream would be temporarily diverted around the work area as part of temporary erosion and sediment control. The diversion may involve using pumps to remove water from the channel just upstream of the work area. The water would be discharged just downstream of the work area. No waste material would be discharged to surface or groundwater. f) Reuse of Site. The project goal is to reduce the duration of flooding on rural residential properties and actively used pastures at the start and end of the rainy season by removing in-stream obstructions. The project area is anticipated to remain in a natural state . . g) Transferability of Special Permit Special Permits are transferrable to other persons, firms and corporations, and the special permit shall continue with the activity on the site unless a new special permit is granted. h} Permit Expiration The Special Permit for Grade and Fill shall be null and void if the applicant has not begun activity within six months after the granting of the permit, unless the Hearing Examiner grants an extension of time. Special Permits are valid until' the approved plans have been satisfactorily completed. The applicant will also be required to obtain an Annual Grading License from the City of Renton for the term of the work. HEX Report City of Renton Department of Corr ,ity & Economic Development Prr ·r,ary Report to the Hearing Examiner MAY CREEK DRAINAGE IMPROVEt,,_,~T PROJECT LUA13-DDD187, V-H, SP Hearing Date: April 16, 2013 Page 10 of 14 i) Revocation of Permit The Community and Economic Development Department is authorized to revoke any annual license issued pursuant to the terms of the Grading, Excavation and Mining Regulations if after due investigation it is determined that the permittee has violated any of the provisions of this Ordinance. Notice of revocation shall have reasonable time not to exceed forty-five (45) days in which to remedy the defects or omission specified. In the event that the licensee fails or neglects to do so within the time period, the order of revocation shall be final. A total or partial stop work order may be issued for good reason. 5. Critical Areas Variance a) Findings: 1. Request -The applicant is requesting to remove sediment and vegetation within May Creek, a Class 2 stream. The area contains a Category 3 wetland on both sides of the stream. The proposal would be to vary from RMC 4-3-050E.2 which states that critical areas and any associated buffers shall be avoided and undisturbed. 2. Variance -Alterations of streams and wetlands require a Hearing Examiner Variance per RMC 4-9-2508.1. 3. Existing Land Uses -The project area is surrounded by vacant natural land and low density single-family residential uses and is designated Residential Low Density (RLD) in the City's Comprehensive Plan. 4. Zoning-Residential -1 dwelling unit per acre (R-1) zone. 5. Topography -The project site includes a shallow stream channel and surrounding banks which slope upward to the north and south. 6. Hydraulic Permit Approval -Washington Department of Fish and Wildlife has issued Hydraulic Permit Approval (HPA) to allow project work between June 16 and September 15 (Exhibit 28). The work is to be completed by August 10, 2016 per the HPA. 7. Public Notice -The project was properly po.sted and notices mailed to surrounding property owners on March 21, 2013 (Exhibit 34). No public comments were received . . b) Consistency with Variance Criteria: Section 4-9-250810 lists 10 criteria that the Hearing Examiner is asked to consider, along with other relevant information, in making a decision on a variance application. These include the following: 1. Public policies have been evaluated and it has been determined by the Hearing Examiner that the public's health safety and welfare is best served. The applicant states that the project has been designed to protect public health and safety. The applicant also states that to protect public health and welfare during construction activities, public access will be limited. Construction crews would allow public access to these areas only when public health and safety can be maintained. The applicant has submitted materials which analyze the potential effects on adjacent properties downstream of the project area. As stated in the Project Description/Background Section of this report, additional analysis and comments from Dr. Patricia Olson at the Deportment of Ecology regarding the proposed project have been submitted. Both the HEX Report City of Renton Department of Corr ,ity & Economic Development Pr •nary Report to the Hearing Examiner MAY CREEK DRAINAGE IMPROVEo..-NT PROJECT WAl3-000187, V-H, SP Hearing Date: April 16, 2013 Page 11 of 14 applicant and the Department af Ecology have concluded that the project would not likely create a measurable increase in bank erosion downstream from the project site and flooding problems have not been identified as an area of concern (Exhibit 24). Based on the analysis provided by the applicant and the Department of Ecology, staff concurs that the public's health, safety, and welfare is best served. 2. Each facility must conform to the Comprehensive Plan and with any adopted public programs and policies. The applicant states that proposed project would not change existing land use and, therefore, would, be in conformance with the Comprehensive Plan and other public programs and policies. Staff concurs that the proposed project would not affect existing land use. Furthermore, the proposed project would satisfy the following Comprehensive Plan policies: Policy EN-1 -Manage water resources for multiple uses including recreation, fish and wildlife, flood protection, erosion control, water supply, energy production, and open space; Policy EN-2 -Minimize erosion and sedimentation by requiring appropriate construction techniques and resource practices; Policy EN-4 -Degraded channels, streams, creeks, and banks should be naturalized by public programs and new development. 3. Each facility must serve established, identified public needs. Staff concurs with the applicant that the proposed project would result in the protection of both residential properties and agricultural uses from flooding. 4. No practical alternative exists to meet the needs. The applicant examined four other alternatives: 1. Restore May Creek channel corridor that corresponds to the King County regulatory buffer of 330 feet {165 feet on either side of the stream); 2. Construct flood control berms along May Creek; 3. Construct upland stormwater controls for upland sources of sediment, including the addition of retention and detention facilities; and 4. Implementation of farm management plans and construction of farm pods. The applicant chose the proposed project, which includes removing channel obstructions while also providing compensatory.stream and wetland mitigation, because it is the alternative with the least adverse impact on critical areas and was within the King County budget. Staff recognizes that the preferred alternative and the four rejected alternatives were vetted during the environmental (SEPA) review process. s. The proposed action takes affirmative and appropriate measures to minimize and compensate for unavoidable impacts. HEX Report City of Renton Department of Corr ,ity & Economic Development Pr inary Report to the Hearing Examiner MAY CREEK DRAINAGE IMPROVEi •. _NT PROJECT LUA13-000187, V-H, SP Hearing Date: April 16, 2013 Page 12 of 14 The applicant states that the project has been designed to avoid and minimize adverse impacts on critical areas ta the extent possible without compromising the project goals. The following measures would be fa/lawed: o Construction equipment would use existing roads, whenever possible to cross the wetland, floodplain, and stream; o When wetland access outside of existing roads is needed, only rubber tired or tracked · vehicles would be used to minimize ground disturbance; o Temporary erosion and sediment control best management practices, such as silt fences or coir logs, would be used to prevent sediment-laden stormwater from entering the stream or wetland; o Any wetland areas that are temporarily disturbed during construction would be restored with native wetland vegetation after construction is completed; o In order to minimize the amount of temporary ground disturbance in the wetland, reed canary grass would be removed from the planting area using a weed barrier fabric instead of excavation. Native vegetation would be planted through the fabric; o All in-water work would be conducted during the summer low flaw construction work window (June 16 through September 15} designated to protect aquatic species; o During sediment removal, the stream would be temporarily diverted around the work area as part af the temporary erosion and sediment control plan. o In-stream vegetation removal would be by hand, when possible, to minimize turbidity in the stream and to avoid removing more vegetation than is necessary to restore flaw · conditions; o Hand removal of in-stream willow branches would be limited to the minimum amount required to restore flow canditians; and o May Creek would be protected during canstructian af the off-channel alcoves west of 14B'h Avenue SE by leaving an earth plug between the existing stream channel and the excavation area for the a/cave. Prior to removing the earth plug and connecting the alcove to the existing channel, a turbidity curtain would be installed to protect the stream during the connection. Staff agrees that the applicant has incorporated affirmative and appropriate measures to minimize and compensate for unavoidable impacts. 6. The proposed activity proposes no net loss of regulated wetland or stream/lake area, value, or function in the drainage basin where the wetland, stream, or lake is located. HEX Report The applicant maintains that the proposed project would not result in a loss of regulated wetland or function. The sediment and vegetation removal would impact existing in-stream habitat. Compensatory mitigation is proposed to offset these impacts. Such compensatory mitigation is contained in the Stream and Wetland Impact Analysis and Mitigation Plan, Revised July 2011 (Exhibit 13}. The proposed project would provide additional stream alcoves with plantings which would include Hardstem bu/brush, Common spike-rush, Sawbeak sedge, Red-osier dogwood, Pacific ninebark, Pea fruited rose, Salmonberry, Sitka willow, Pacific City of Renton Department of Corr 1ity & Economic Development Pr inary Report to the Hearing Examiner MAY CREEK DRAINAGE IMPROVE,,,_/VT PROJECT LUA13-000187, V-H, SP Hearing Date: April 16, 2013 Page 13 of 14 willow, ond Black cottonwood. Riparian buffer planting would include Red alder, Sitka spruce, Black cottonwood, Western red cedar; Red-osier dogwood, Pacific willow, and Oregon ash. In addition, large woody debris will be anchored to serve as wildlife habitat, while ensuring fish passage. Staff concurs with the applicant that no net loss of wetland or stream area, value or function in the drainage basin would ,occur and has approved the Draft Mitigation Plan (Exhibit 13}. Renton Municipal Code requires monitoring of the mitigation and surety devices to ensure survival of the plantings and performance of the mitigation. King County will be required to provide the necessary mitigation monitoring surety devices and monitoring reports (quarterly the first year, and annually thereafter for 4 additional years). 7. The proposed activities will not jeopardize the continued existence of endangered, threatened or sensitive species as listed by the Federal government or the State- The applicant states that the proposed project has been evaluated under Section 7 of the Endangered Species Act (Exhibit 27). The evaluation determined that the project may affect but is not likely to adversely affect Chinook salmon and steelhead trout. The applicant further states that the proposed project would have no effect on bull trout. No other sensitive species are located in the project area. Staff concurs with the applicant's evaluation. 8. That the proposed activities will not cause significant degradation of groundwater or surface water quality. The applicant states that Best Management Practices would be used during construction to protect groundwater and surface water quality. These are described in Section 5.1 of the Stream and Wetland Impact Analysis and Mitigation Plan (Exhibit 13} for the project. Construction and post-construction monitoring of surface water and groundwater would be conducted as described in section 6.2 of the Stream and Wetland Impact Analysis and Mitigation Plan for the project. This project received an Individual 401 Water Quality Certification from the Washington State Department of Ecology {DOE) on January 8, 2013 {Exhibit 25) and will follow all permit conditions set forth by DOE for the protection of groundwater and surface water. In addition, Construction Notes shown on Exhibit 6 provide for measures to reintroduce surface flow to the new and dry channel to control turbidity and meet state water quality standards. Staff agrees with the applicant's use of Best Management Practices to protect groundwater and surface water. 9. The approval as determined by the Reviewing Official is a minimum variance that will accomplish the desired purpose. HEX Report The applicant maintains that the proposed project has been designed to avoid and minimize adverse impacts on critical areas to the maximum extent possible without compromising the project goals and is therefore the minimum variance possible. Staff agrees that this is the minimum variance to accomplish the project goals. Grading and disturbance is being minimized on the site, while enhancement and restoration of the wetland and stream areas would occur. City of Renton Department of Corr 1ity & Economic Development Pr 'nary Report to the Hearing Examiner MAY CREEK DRAINAGE IMPROVE, •. _.VT PROJECT LUA13-000187, V-H, SP Hearing Date: April 16, 2013 Page 14 of 14 10. The proposed variance is based on consideration of the best available science as described in WAC 365-195-905; or where there is an absence of valid scientific information, the steps in RMC 4-9-250F are followed. The applicant maintains that the best available science was used in the preparation of the following reports: o Wetland Delineation Report, March 2010; o Baseline Stream Conditions, Revised December 2, 2010; o Hydraulic and Hydrologic Analyses, December 17, 2010; o Sediment Assessment, February 2011; o Stream and Wetland Impact Analysis and Mitigation Plan, Revised July 2011; o Biological Evaluation Report for Chinook Salmon and Steel head Trout as protected under the Endangered Species Act, February 2011; o Construction Water Quality Protection an.d Monitoring Plan, July 2011. Staff concurs that the applicant employed the use of best available science in the above documents per WAC 365-195-905 which permits counties and cities to use information that local, state or federal natural resource agencies have determined represents the best available science consistent with the criteria set out in WAC 365-195-900 through 365-195-925. I H. RECOMMENDATION: Staff recommends approval of Special Permit for Grade and Fill and a Critical Areas Variance from RMC 4-3-0SOE.2 for the May Creek Drainage Improvement Project; Project File No. LUAl0-065, V- H, SP subject to the following conditions: 1. Compliance with the mitigation measures contained in the Mitigated Determination of Non- Significance, issued by the King County Water and Land Resources Division, Department of Natural Resources and Parks, dated September 8, 2011 (Exhibit 12). 2. The applicant shall also comply with the Stream and Wetland Impact Analysis and Mitigation Plan (Exhibit 13, Revised September 2011) throughout and following construction. HEX Report I Mai~ C1ree~ ID1raioroaige imp1rovemerot IP1roject 0 1:2,319 193 0 97 NAD_ 1983_HARN_StatePlane_ Washington_ North_FIPS_ 4601 193 Feet City of Renton® Finance & IT Division Legend Jurisdiction Boundaries [1 Other [J City of Renton Addresses D Parcels Overlay Districts [2J AutoMallA D Auto Mali B a Employment Area Valley ~, City Center Sign Regulation Area lnfonnatlon Technology. GIS RentonMepSupport@Rentonwa.gov 4/9/2013 EJ Urban Design District D Environment Designations O Natural D Shoreline High Intensity IEXHIIBIT 2 This map is a user generated static output from an Internet mapping site end is for relerenc.e only. Data layers that appear on this map may or may not be accurate. current, or otheiwise reliable THIS MAP IS NOTTO BE USED FOR NAVIGATION VICINITY MAP \ l COAl.FlELD INOEX ..s.t:!.llI.. DESCRIPTION 1. VICINITY MAP AND INDEX 2. L.fGtNDS AND ABBREVIA.TIONS 3. SUMMARY OF QUANTITIES 4. EXISTING CONOffiONS, SHEET KEY. LEGEND, CONSTRUCTION NOTES 5. TEMPORARY· EROSION AND SEDIMENT CONTROL PLAN ANO LEGEND 6. TEMPORARY EROSION AND SEDIMENT COITTROL PLAN 7. n'.SC SEDIMENT DISPOSAL ANO TUR810 WATER DISPERSION LOCATIONS 8. TEMPORMY EROSION ANO SEDIMENT CONTROL NOTES AND DETAILS 9. TEMPORARY EROSION ANO SEDIMENT CONTROl DETAILS 10. PLAN AND PROALE, STA. 0+00 TO STA B+OO 11. PLAN AND PROFILE, STA. 8+00 TO STA. 16+20 12. PLAN AND PROfllE, STA. 16+20 TO STA. 24+00 13. PLAN AND PROFILE. STA. 24+00 TO STA 29+00 END OF PROJECT 14. WEJl.NIIO AND RIP~ MffiGATIOH Pl.AN, STA. 0+00 TO STA. 7+00 15. CROSS SECTIONS ANO HABITAT MmGATION DETAILS m >< 16. LOG Pl.ACEMEN'T, LOG TABU:, ANCHORING NOTES, SNAG DETAIL AND NOTES 17. HABITAT MmGATION DETAILS: fABRIC APPLICATION 18. HABITAT MmGATION ENHANCEMENT: FENCE AND WETI..ANO SIGNAGE DETAILS 19. Pl.ANTING TABLES AND NOTES 20. PV,N'TlNG P1>N :c ..... m -· 01-201 :cMm' 01-2010 l=I (U(IT 02-2010 11!. -· """' ~. -Pl!OJECT HD.~ ~ '· PI..S 02-2010 --~ 1 ZOU SUIMY Ho._ w I ,_ ITIDl'.![ 1 __ ... 1 ZOU ~~~ ~ King County Department of Natural Resources and Parks Water and Land Resources Division Stormwater Services Section Capital Services Unit CMI.Oe True, Dlreclor Department or Natural Resources and Parts MAY CREEK DRAINAGE IMPROVEMENT SE May Valley Rd.+ 148th Ave SE City of Renton Planning Division MAY CREEK ORAINAClE IMPROVEMENT 1 2 ZUIJ l;!J King County ,r'I -----.i...c --~-----------Y'CN1Y MAP At<> NJeX IQ) SH[(T 1 "' 20 SHEDS 2006-16 • ' i •• l • -3 '. 'ti . l \ i{ ~ t ii Ii ~ • 0 I !EXHIBIT 4 ....... rnmrn JR INTERVAL: 1' m >< ::r: 1-1 m 1-1 -I U'i N KING COUt<TY JAN. 2010. DOOM 01-201, 1011N1Y Ol-1010 OUNTY 0?-111111 r, FU !;12.-Z0111 - --- / ~ - r I I .~ J5 _________., • ~ -/ ; ~ ~ '-- " \ EXISTING TOE OF STREAMBEO . ~----(' ~L .,. ' ~., ,, ··~+ / /~ '·""·-----~'. -' -•+ -·~ 0',_, ~ tr·-" --. \ ·~ ~ I . \ / . rY_ I·-··-\ --··~ ,,, - I I \ I I • -poN-".ffl.S!SEII.PL ---- ----- -rwrooSQli j,mul --M-e•oo1e f,aoul --· 1114811' ~ King County c::c =="i!.~-:..,"""r'l!'I ------ 111 11 a 1 1 I I <O 9 tO m ·~ SCAU" >ttl ./ SHEET " ~ 2006-16 fi'I )( ~ M 00 :i Ci\ ~' 1. HOl.O PRECONS'fRUCOON MCETN;. 2. ESTABUSH RrQUIRED SICNACt NIO llWTIC Pl.AN REaUIREMrNTS. J. STN<E OR n..-.; nu: LIMITS Of CONSTRUCTJON. SU: NOTES 1J, Hi, N<ID 17 FOR CONSfRUCTION lJMITS. 4. LOCATE N<ID MARK UlUllES 5. INSTAU. T£UPORMY rROSION CONlROL MU.SURES SHOWN ON SHEITT 5 TO 11. I. INSfAU. CONSTRUCfJON M'.:CESS R/,1,1/' ANO CONSTlfUCTlOH [NllW,jC( PNJ AS NC£0£D NIO APPRO'IEll IN TME ncL0 BY ENGINEER. 7. INSTAU. STMllNG ANO TURN MOUNO MOS AS ~ IN THE flELD BY THE """"" 8. TO. lillN:MIZE 0!5TlnUWa TO EXISTIHG NATIVE VECETATION, MACHINOn' MX:tSS ,IL.ONG THE STR£AM WU ONLY BE ALI.OWED olPPROXIMATRY EVERY 50 FEET AS SHOWN OH SHEETS 5 ANO 11. 9. REMOVE n.DW OBSTRUCTING WII..LI1'fS AS D£SCRl8EO 1H NOTES 13 TO 1!1. 10. ROIOYE SEDIMENT AND R[[D CNWn' GRASS AS DESCRIBED IN NOTES 11 TO 21. 11. REMOVE Nf'f TEMPORARY CONSTRUCllON DITRANCES ANO ACCESS ROAOS THAT ARE NOT NEEDED FOR MITIGATION CONSTRl.lt110N 12, CONSTRUCT MITIGAT10N N<IO R(',l[G£TATE AS Sli0WN ON SKEETS 14 TO 18. El QW QBSIRI ICJ1NG WIJ I OW ffEMQYH NOTfS 1J. WU.OW REMOVAL Will. OCCUR IN snrcrro LOCATIONS FROM STA o-+oo TO STA 5·+.40; SEE TAIU: OH SHEtr 10 AND DaM. Sli£a 15. 14. Wl1.0W BIWOtES AND ROOTS THAT ME UMITINC THE STR£AM FUlW WI.I. BE REMOVED BY !W«I AND/OR IW«lhnD SIUU. IUCHIHERY TO WINIMIZE OISlURBl,NC(. WU0W BRANCHES lHol.T ARE NOT I.AITTING SlREAM flOW WIU. HOT 8£ REMO\'ED. EXACT Wll.l.OWS TO BE REMO'¥EO Will. BE DIREC'IEtl IN THE flEl..D 8Y TliE tNGlNEER OR 8JOLOOIST. 15. WOODY NATIVE VEGETATION THAT IS RDll'.MD W1U. BE Ml/1.CHEO ANO $PROO OVER REED CNWN GRASS TO SHADE OUT GRASS AS OIR(CTID IN THE nEL.D En' TH( ENGINEER OR BIOLOGIST. SEPIMENI AND REED CANAffY CfWiS RfNQYN NIJifS 18. SEDIM£NT f!£MOVN.. IN THE CI-WfHEI. WIU. OCCUR nt0M STA 5-t-40 TO $TA 211+2& 17. REED CANARY GRASS REMOYN.. N 1)4[ CHNltE. WU OCCUR IN sarcr I.OCA.TIONS FROM STA 0-+QO TO STA U+OO. StE TMll.E ON Sli[O 10. 18. MACHINERY FOR REMOVING SEDIMENT AND REED CAN,l,RY GRASS 5HAll. BE OPERATED """ "" """ NOTES cotfflNUEO THIS PACE 'J· OIQ!'i8 I 01-ZOI QC COlNT'I' 01-2010 _...,. DON ALTIWJS.., PL -----~~~~10 ~ DOUC --~ ...... --_9'f_l_ Dlll I ~ D<10Elt M. IWIEU./1 ------ SEC. 2, TWN.2J. R. 5 e,"w.,i. - PfSltlN JffifNO ..., SEDIMENT REMDY"1. AREA IN-STR(AM WILLOW PRUNING AREA I " II I I j ·-. --""'--------~~T JW ~ flOSilttQ j [G[N[) ·-"ll"l((llcTIOl,l)OfmtWI --------Ti.£ ----------WETI.NID 8UfITR {110') PER IONO COUNTY CN:J Af:GUI.ATIOH (FOR PURPOStS Of THIS l'f!OJECT ""-~ -· _ __. --· --fu,a: ' ·-~--11 ',~SOIi S.E. UT YAlt[T /ID \ I \\ r----' -' ' 19. S£ll!MOlf ANO R[ED CANARY GRASS R£MOVAL SHAU. BE DONE IN THE DR'f. A SlR(AM BYPASS PV,N SHAlt. BE SUBMITTED TO THC ENGINED! IN N:NNU Df INSTAIJ.ATIOH DM.RSION AND DEW4TU!lNC SYSTEM PUN TO BYPASS TliE STR£N,I AA0UND WDR1< AREA IN 1 00 TO 50D FOOT S£Ct,tENTS SWDiliG "l JHE I 'PSIRW4 [NQ Of U1f eeorrra Nlf,&, NfJ MtMNG PPYOiSJRE.W SHlti BE SU8MITITD TO lttE ENGINEER IN NNANCE Of INSTM.l,t,TKJN FOR l'1N,,l,l. APPROY4L PRIOR TO BYP"5S!HG Tl-IE STREAM M CONJAACTOR SHAU. SCHE0l1L£ 4 F1SH REMOVAL WITH ltt£ ENGINEER NIID PROVIDE AT LEAST 7 DAYS NOTICE. NO .t:1.EW. BYP"'5S WORK SHAU. fiE....SL!iB.Tt ON A nl!CIAY. lttE KING COUNTY BIOLOGIST Will PERFORM THE FlSH REMOV41.. PRIOR TD INST.w..ATION or E"ACH Of TliE STRu.M DIVERSION SEGMENTS. 20. EXC4VATE SEDIMENT ANO/OR REED CNWff CRASS f"ROM NOW DRY CHANHEL. 21. RETVRN STREAM F'LOW TO TH[ CI-WINEL UNDER DIRECTION Of tNGINEER. PRIOR TO REIHTROOUC!Hll lllE F'l0'/1' TO lllE NEWLY [XCAVAT{D CHANNE1.. A SECOND COFTERDAM ANO SUMP PUMP SHALL BE INST"'-l.EO AT THE DOWl"'5TRE.,t, UWll'S Of" Tl-I( CCIHSTRUCTJOH ARrA. TO ENSURE lHo\T STATE WAlER 0UAUTY CAN BE MET. FUlW Will BE INTRODUCED TO lllE NEWl'I' 0:CAVAltD Cl-WINEL. ANO TURBID WAlER WU. BE PUMPED OUT 4T THE OO!fflSTREAM EHO Of TH( CONSTIU.ICT!ON AREA N<IO Will. BE DISC!W«;ED TO THE lDIPORAR'!' WATER OISPE"510N AAEA, UNTIL THE WATER FLOW n-MOUGH-1HE CHANNO. MEDS STATE W4TER tlUAUTY STN<IDA!lDS. NO TEMPORARY txcucw,ccs Of' STATE W4TEll Ou.<uTY STANDARDS AAE ALLOWEO. -------~~~l~ REG\11.ATION (FOR PURPOSES or THIS PROJECT , .. ~ -~~~A~ BllfrrR) EASEMENT BOUNtW!Y ------~~--_. ___ ,V-----DWN[llm, ll£l1N<D -,oa .,,, nDllDl'lNM \ .. ,'.:",. t ', anninc1 ~ King County ... _., ___ _ I.Ji~-~GE M'ROVEMENT SHEET 4 1 ·2013 , •. 13 KCftlD No. PROJECT No.~ 1 •. ·~ $URYE.Y No. - I '201-' ~~~~ --..------=:=-~ rEB 1 -CXHJll1CN!> l>£ET ""'· ' 1::ttiEH>, c:::oN9TR.ICOON NOTES !Rr~rc~o~~{Q) " 20 SHEETS 2006-16 ]i ' I .L ~· i u. "i! l I " ' f! • r i " p -~ ~, l s I ls,~ ;L~; ~ i'i! iil ~ ! ;!: ! 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STATIONS USlED IN TNII..E 1 B110W I AND PER VECCTATION ROIOYAL CROSS \ SECOON DETAIL SHE'E1' 15 ' l '"' TABLE 1 TASLE2 Stationing of the In-Stream WIiiow Pruning fur May en,,,k Slatlonlng of lhe In Slrearn Reed Canary Gras RemoY8I -·-_,, -·-_,, 0•00 "~ "~ OHO 0+70 .. ~ ,.,, ~00 ,,oo .. ~ ... , '"' .. ~ 5+40 H+28 29+00 Jl5.0 :.;_~3<r- _J!O.O __ _ ~ \ HOTCS: '°""' "'°"~OBSTRUCTlNG OWfNEl. 1, SEDIMENT REMOVAL FROM STA. 5+40 TO STA. 26""2.6 ~CTI~ ~Wl OGIST ~~~ti': PER Z. STAGING AA£A SHOWN ON SHEET 5 (SE~Y PROPERiY) VEG.ETATION R OYAl C!I.OSS S£CTI0N DETAIL c:=::=& · 1. -· '111::::11 ON 5HEEr 15 D TABlE 2 ON 1111$ star. ... . . ... ·: ··~~ '\-f'q _., -'··-,;·CIIII· ·8911> u:aa,···-........ ·-8 _,_,.. _____ _ -- -- \ I T, ,ABLE3 1-Sta11on1ng or Sedlmanl llfld V9gNllon __ . ~- Remo'<al •• -~-.. ~~ ------,. , .. , 26+28 ... --~-····711· .. --------~ ········· \_ .. . ... .) ........... 1111, [~-•-•---.L..••-··• I /i:Li::--1 I ~ ~....::-: -,-' J--=-l ... r .. ·,~·· ~ . I IOT G ™ C EL 8£Lo ELCV... ~ ·: 1 ··- ~, ~I ~. 11 I I -,J J10.0 T 1, I J05.0 m >< :i:: -0+60 -o+Jo o+oo o+JO 0+60 o+90 1+20 1+50 1+80 2+10 2+40 2+70 J+OO J+JO J+SO J+90 4+20 H50 <+BO 5+10 S+JO 6+60 SHO\..iffjr or Renton JOO.O 6+90 7+20 7+50 7+80 CAl.l.. 2 WOAIClNO DAYS BEFORE YOU DIO rB00-424-5555 -tmlll'YI.OCA_ ... _) 1-1 0:, ~ t-6 I-"' OIO~e 01-201 ro\lHTT 01-2010 ::o\llnY 01-2010 ll'. PU OZ-2010 -~ ~L~ I ..,..._---..._mo.l.JSERP.t. 1 '201• :":, --··-Clfll'I 1-1J KCF'CZO No. PIIOJECT No. _!.!!:!!JIii_ gagCD, ML IIDSON I '20IJ SLIRVEl' ""·- _Dl1UID, ... IIAOOJ.,\ 1 -·13 ~ Pfenning Divis' MJ King Cou~.,J.,!j :'"=t::=.....-. ------~ MAY ~-DRAINAGE IMPROVEMENT 'OTJ '[D SHEET 10 " 20 SHEETS 2006-16 • King County . Water and Land Resources Division Department of Natural Resources and Parks King Street Center 201 South Jackson Street, Suite 600 Seattle, WA 98104·3855 206-296-6519 Fax 206·296·0192 TlY Relay: 711 Mitigated Determination of Non-Significance Date of Issue: September 8, 2010 Name of Proposal: May Creek Drainage Improvement Project (9Al 205) !EXHIBIT 12 Description of Proposal: King County's Water and Land Resources Division proposes to improve in-stream flow conditions along segments of May Creek in May Valley between approximately River Mile 4.3 and 4.9. Sediment accumulation and in-stream vegetation ( e.g., reed canarygrass and willows) throughout the valley reach of May Creek have been gradually decreasing channel flow capacity, causing a backwater effect. This is increasing the duration of flooding in actively used pastures on adjacent rural residential properties with flood conditions now persisting well into the summer months. The goal of this project is to reduce the duration of flooding on these properties at both the start and end of the rainy season by removing in-stream channel obstructions. This effort should help alleviate the duration of localized flooding on adjacent properties during low to moderate storm events and should allow the pastures to drain more effectively when flooding does occur. Due to the high groundwater table in the May Valley and because there will be no measureable difference in the geographic extent of flooding, it is not likely that this project will change the amount of wet pasture or wetland in the project vicinity. In addition, the project hydraulic analysis found that the potential for erosion downstream of May Valley is virtually unchanged for the pre-versus post-project conditions. Flow obstructing in-stream vegetation and accumulated sediment will be removed from the stream channel primarily using machinery operated from the stream bank. The vegetation and sediment removal will negatively impact existing in-stream fish habitat.. Mitigation has been proposed to offset these impacts. Mitigation: The following mitigation will be implemented to avoid, minimize, and compensate for negative impacts to the in-stream and wetland habitat. o During construction, the stream flow will be diverted around the work area, and in-water work will only be conducted during the summer low flow when fish are less likely to be present. A King County biologist will be onsite during construction to monitor water quality. o Construction techniques, such as utilizing existing access roads or using temporary steel plates (or equivalent), where additional access is needed, will minimize disturbance to existing vegetation. In addition, direct access to the stream channel by equipment will only be allowed in specific areas where vegetation disturbance can be minimized. o Approximately 1.3 acres of wetland and riparian vegetation will be planted along May Creek (15 feet on each side of the stream from 148th Avenue SE upstream to the end of the project). Fencing will be installed to protect the plantings and the stream from livestock. 8/3112010 Mitigated Determination of Non-Significance May Creek Drainage Improvement Project Page 2 o Approximately 3.75 acres of wetland will be enhanced on the west side of 148th Avenue SE by removing invasive reed canarygrass and replanting with native wetland vegetation. Off- channel alcoves will also be excavated along May Creek in this location and large woody debris and streambed gravel will be added in the alcoves to enhance wetland fish habitat. o Fish habitat and natural stream processes will be restored at either the confluence of Long Marsh Creek and May Creek, or at another similar location in the project vicinity. Location of Proposal: The project is located in the May Valley near the cities of Renton and Newcastle (Sections 2 and 3, Township 23N, Range SE) on the south side of SE May Valley Road. The project area includes multiple segments of May Creek between approximately River Mile 4.3 (about 0.25 miles downstream of 148th Avenue SE in Renton) and River Mile 4.9. Responsible Official: Position/Title: Address: DATE: q-'Z,-/0 Proponent and Lead Agency: Contact Person(s): Mark. Isaacson Division Director, Water and Land Resources Division 20 l South Jackson Street, Suite 600 Seattle, WA981zp4-~ J/ SIGNATURE: .~op • King County Department of Natural Resources and Parks Water and Land Resources Division Doug Chin, Project Manager, 206-296~83 l 5 The lead agency for this proposal has determined that it does not have a probable significant adverse impact on the environment. An Environmental Impact Statement (EIS) is not required under Revised Code of Washington (RCW) 43.21C.030(2)(c). This decision was made after review of a completed environmental checklist and other information on file with the lead agency. THIS INFORMATION IS AVAILABLE TO THE PUBLIC ON REQUEST (for a nominal photocopying fee). It is also available on the King County website at:· http://www.kingcounty.gov/environmet1t/watersheds/cedar-river-lake-wa/may-creek.aspx THIS MITIGATED DETERMINATION OF NON-SIGNIFICANCE (MONS) is issued under Washington Administrative Code (WAC) l 97-11-340(2). The lead agency will not act on this proposal until after September 22, 2010. Comments must be submitted or postmarked by that date. For additional information, please contact: Doug Chin, Project Manager King County Water and Land Resources Division 201 South Jackson Street, Suite 600 Seattle, WA 98104-3855 (206) 296-8315 Doug.Chin@kingcounty.gov 8/J tl10tO Purpose of Checklist: i~ff lal King County Environmental Checklist May Creek Channel Restoration Project The State Environmental Policy Act (SEPA), chapter 43.21 C RCW, requires all governmental agencies to consider the environmental impacts of a proposal before making decisions. An environmental impact statement (EIS) must be prepared for all proposals with probable significant adverse impacts on the quality of the environment. The purpose of this checklist is to provide information to help you and the agency identify impacts from your proposal (and to reduce or avoid impacts from the proposal, ifit can be done) and to help the agency decide whether an EIS is required. Instructions for applicants: This environmental checklist asks you to describe some basic information about your proposal. Governmental agencies use this checklist to determine whether the environmental impacts of your proposal are significant, requiring preparation of an EIS. Answer the questions briefly, with the most precise information known, or give the best description you can. You must answer each question accurately and carefully, to the best of your knowledge. In most cases, you should be able to answer the questions from your own observations or project plans without the need to hire experts. If you really do not know the answer, or if a question does not apply to your proposal, write "do not know" or "does not apply." Complete answers to the questions now may avoid unnecessary delays later. Some questions ask about governmental regulations, such as zoning, shoreline, and landmark designations. Answer these questions if you can. If you have problems, the governmental agencies can assist you. The checklist questions apply to all parts of your proposal, even if you plan to do them over a period of time or on different parcels oflarid. Attach any additional information that will help describe your proposal or its environmental effects. The agency to which you submit this checklist may ask you to explain your answers or provide additional information reasonably related to determining if there may be significant adverse in1pact. Use of Checklist for Nonproject Proposals: Complete this checklist for nonproject proposals, even though questions may be answered "does not apply." IN ADDITION, complete the SUPPLEMENTAL SHEET FOR NONPROJECT ACTIONS (part D). · For nonproject actions, the references in the checklist to the words "project," "applicant," and "property or site" should be read as "proposal," "proposer," and "affected geographic area," respectively. KING COUNTY ENVIRONi,~.,NTAL CHECKLIST May Creek Drainage Improvement Project A. BACKGROUND 1. Name of proposed project, if applicable: May Creek Drainage Improvement Project (9Al205) 2. Name of applicant: King County Department of Natural Resources and Parks Water and Land Resources Division 3. Address and phone number of applicant an.d contact person: 201 South Jackson Street, Suite 600 Seattle, WA 98104-3855 Contact: Doug Chin, Project Manager Phone: (206) 296-8315 Fax: (206) 296-0192 Email: Doug.Chin@kingcounty.gov 4. Date checklist prepared: August2010 5. Agency requesting checklist: King County Department of Natural Resources and Parks Water and Land Resources Division 6. Proposed timing or schedule (including phasing, if applicable): The activities described in this checklist are estimated to be completed in the summer of 2011, except for the planting which will be completed during the dormant season (approximately November 2011 to February 2012). The exact project schedule is dependent on when the necessary permits and property owner agreements are obtained. 7. Do you have any plans for fature additions, expansion, or farther activity related to or connected with this proposal? If yes, explain. Yes. The May Creek Basin Action Plan (King County 2001) and the May Creek Drainage and Restoration Plan (GeoEngineers Inc. 2008) make a series ofrecommendations to reduce flooding and improve habitat in May Valley. These include the removal of channel obstructions such as beaver darns, accumulated sediment, and vegetation choking the channel. This project addresses a subset of 2 KING COUNTY ENVIROi"«ENTAL CHECKLIST· May Creek Drainage Improvement Project the drainage improvements and restoration recommendations in these plans; additional recommended actions may be proposed as future projects. 8. List any environmental information you know about that has been prepared, or will be prepared, directly related to this proposal. The following documentation has already been prepared and is directly related to this proposal: o May Creek Current and Future Conditions Report (King County and City of Renton 1995) o May Creek Basin Action Plan (King County 2001) o May Creek Drainage and Restoration Plan (GeoEngineers Inc. 2008) o May Creek Erosion Stabilization Draft Report -May Creek Sediment Transport Study Phase 3 (Anchor QEA LLC 2010) o May Creek Wetland Delineation Report (King County 2010) o May Creek Baseline Stream Conditions (King County 2010) o May Creek Hydraulic Study (King County 2010) The following documentation has not yet been finalized for this project: o May Creek Stream and Wetland Mitigation Plan o May Creek Detailed Stream Habitat Survey o Effects Determination for Section 7 of the Endangered Species Act 9. Do you know whether applications are pending for governmental approvals of other proposals directly affecting the property covered by your proposal? If yes, explain. None are known to be pending. 10. List any government approvals or permits that will be needed for your proposal, if known. The following permits will likely be required for this project. The exact list of required permits will be determined based on feedback received from the regulatory agencies. o U.S. Anny Corps of Engineers Section 404 Individual Pennit o Compliance with Section 7 of the Endangered Species Act o Compliance with Section I 06 of National Historical Preservation Act o Washington Department of Ecology 401 Water Quality Certification o Washington Department of Ecology National Pollutant Discharge Elimination System Pennit o Washington Department of Fish and Wildlife Hydraulic Project Approval o King County DDES Clearing and Grading Permit o King CountyDDES Critical Area Alteration Exception o City of Renton Grade and Fill Permit o City of Renton Critical Areas Variance 3 KING COUNTY ENVIRON1"u,NT AL CHECKLIST ' May Creek Drainage Improvement Project 11. Give brief. complete description of your proposal, including the proposed uses and the size of the project and site. There are several questions later in this checklist that ask you to describe certain aspects of your proposal. You do not need to repeat those answers on this page .. King County's Water and Land Resources Division proposes to improve in-stream flow conditions along segments of May Creek in May Valley between approximately River Mile 4.3 and 4.9. Sediment accumulation and in-stream vegetation (e.g., reed canarygrass and willows) throughout the valley reach of May Creek have been gradually decreasing channel flow capacity, causing a backwater effect. This is increasing the duration of flooding in actively used pastures on adjacent rural residential properties with flood conditions now persisting well into the summer months. The goal of this project is to reduce the duration of flooding on these properties at both the start and end of the rainy season by removing in-stream channel obstructions. This effort should help alleviate the duration of localized flooding on adjacent properties during low to moderate storm events and should allow the pastures to drain more effectively when flooding does occur. Due to the high groundwater table in the May Valley and, because there will be no measureable difference in the geographical extent of flooding, it is not likely that this project will change the amount of wet pasture or wetland in the project vicinity. King County implemented a similar pilot project along 300 linear feet of May Creek in 2002 and, as a result, less overbank flooding now occurs during small storm events along this reach. This project proposal consists of three components: vegetation removal, sediment removal, and stream/wetland mitigation. The vegetation and sediment removal will negatively impact existing in- stream fish habitat, so mitigation has been proposed to offset these impacts. The mitigation is also designed to improve the longevity of the project by decreasing the opportunity for channel obstructions to form in the future. The project components are described below. Vegetation Removal: The first component of the project includes removal of flow obstructing in- ", stream vegetation and debris from specific reaches where it is choking the channel and creating a backwater effect, causing flooding on adjacent properties during small storm events. Invasive reed canarygrass is the dominant vegetation that will be removed from the channel and banks. In addition, willows, located in multiple locations throughout the project area, are currently growing in the middle of the channel, further contributing to the backwater effect. A portion of the willows that are identified as obstructing flow will also be removed. The willows will be primarily removed by hand, but some small, hand-held, mechanized machinery may be used to assist. The reed canarygrass that is growing in the channel will be removed with machinery, most likely a trackhoe, operated from the stream bank. Prior to removal of the reed canary grass, the stream will be diverted around the construction site and erosion and sediment control best management practices will be used during construction to minimize temporary downstream water quality impacts. Sediment Removal: Sediment will be removed from the stream channel using machinery, most likely a trackhoe, operated from the stream bank. The stream will be diverted around the construction site and erosion and sediment control best management practices will be used during construction to minimize temporary downstream water quality impacts. Construction techniques, such as utilizing existing access roads or using temporary steel plates (or equivalent) where additional access is needed, will be used to minimize temporary impacts to adjacent wetlands. 4 KING COUNTY ENVIRO&NTAL CHECKLIST May Creek Drainage Improvement Project Stream/Wetland Mitigation: The final component of the project includes providing mitigation to avoid, minimize, and compensate for in-stream and wetland habitat impacts as well as implementing measures that will increase the longevity of the project. The following mitigation will be implemented: o During construction, the stream flow will be diverted around the work area, and in-water work will only be conducted during the summer low flow when fish are less likely to be present. A King · County biologist will be onsite during construction to monitor water quality. o Construction techniques, such as utilizing existing access roads or using temporary steel plates ( or equivalent), where additional access is needed, will minimize disturbance to existing vegetation. In addition, direct access to the stream channel by equipment will only be allowed in specific areas where vegetation disturbance can be minimized. o A buffer of native vegetation (primarily wetland vegetation) will be restored for approximately 15 feet on each side of May Creek from 148th Avenue SE upstream to the eastern end of the project limits for a total of approximately 1.3 acres. This buffer is intended to shade out future reed canarygrass and to compensate for the cover that will be lost by removing flow obstructing willows and reed canarygrass. The native vegetation will be planted in areas where, under existing conditions, virtually no native vegetated buffer exists. In most of the project area, the regulatory stream buffer is contained within the delineated wetland boundary, which means that stream buffer enhancement could also be considered wetland enhancement. Fencing will be installed around the planting areas to minimize livestock access to the newly planted areas and to the stream. o Wetland enhancement will be performed by removing invasive vegetation within the wetland (mostly reed canarygrass) and replanting approximately 3.75 acres of native wetland vegetation in the open space tract on the west side of 148th Avenue SE. Off-channel alcoves will also be excavated along May Creek within the wetland in this location and large woody debris will be added in the alcoves to partially compensate for the loss of in-stream habitat complexity that will occur as a result of removing flow obstructing vegetation. o Additional in-stream habitat restoration may occur at the confluence of Long Marsh Creek and May Creek.. If implemented, this mitigation will restore fish habitat complexity at the confluence of these two streams. It will also restore the alluvial fan functions by removing the stream from the agricultural ditch and relocating it into a more natural channel, allowing sediment to drop out in Long Marsh Creek prior to reaching May Creek. If King County is unable to reach an agreement with the property owner to perform this mitigation, then similar mitigation will be proposed at another location either in the immediate project area or offsite. 5 KING COUNTY ENVIRoANTAL CHECKLIST ./ May Creek Drainage Improvement Project 12. Location of the proposal. Give sufficient information for a person to understand the precise location of your proposed project, including a street address, if any, and section, township, and range, if known. If a proposal would occur over a range of area, provide the range or boundaries of the site(s). Provide a legal description, site plan, vicinity map, and topographic map, if reasonably available. While you should submit any plans required by the agency, you are not required to duplicate maps or detailed plans submitted with any permit applications related to this checklist. The project is located in May Valley near the cities of Renton and Newcastle (Sections 2 and 3, · Township 23N, Range 5E) on the south side of SE May Valley Road. The project area includes the reach of May Creek between approximately River Mile 4.3 (about 0.25 miles downstream of 148th Avenue SE in Renton) and River Mile 4.9. Please see the attached vicinity map. B. ENVIRONMENTAL ELEMENTS 1. Earth . a. General description of the site (circle one): jJgJ, rolling, hilly, steep slopes, mountainous, other. All of the proposed work will be completed within the May Valley, which is a flat, broad valley with little variation in elevation. The channel' through this area has a very low gradient (0.2 percent slope), and as a result is prone to sediment accumulation. b. What is the steepest slope on the site (approximate percent slope)? The valley is flat with little variation across the floodplain. On both sides of the valley, the elevations rise quickly, with slopes ranging from 6 to 30 percent. c. What general types of soils are found on the site (for example, clay, sand, gravel, peat, muck)? If you know the classification of agricultural soils, specify them and note any ·prime farmland. The U.S. Department of Agriculture National Resources Conservation Service Web Soil Survey (2009) for King County identifies Bellingham silt loam as the primary soil on the valley floor. At the higher elevations, adjacent to the valley, Ragnar-Indianola association and Alderwood gravelly sandy loam are identified. Soil investigations during the wetland survey also found areas with a high concentration of clay. d. Are there surface indications or history of unstable soils in the immediate vicinity? If so, describe. There is no evidence of surface instability near the subject property. 6 KING COUNTY ENVIRO~.dENTAL CHECKLIST May Creek Drainage Improvement Project e. Describe the purpose, type, and approximate quantities of any filling or grading proposed Indicate source of fill. The purpose of this project is to remove channel obstructions from May Creek, including accumulated sediment and flow obstructing vegetation. Approximately 4,000 cubic yards of sediment will be excavated from May Creek. The removed sediment will either be disposed of appropriately offsite, or will be spread in an approved area adjacent to the project site in coordination with the property owner and as allowed by regulations and pemrits. As mitigation, the project proposes to restore approximately five acres of native vegetation (primarily wetland vegetation adjacent to the stream) through out the project area. This restoration will include shading out reed canarygrass using a sheet mulch treatment, such as cardboard or weed fabric, and replanting with native vegetation. In addition, approximately 76 pieces of large woody debris will be placed throughout the . mitigation areas, and approximately 32 cubic yards of streambed gravel will be placed in off-channel alcoves west of 148th Avenue NE. Streambed gravel will also be placed at the potentially restored confluence of Long Marsh Creek and May Creek, but the exact quantity at this location has not been determined yet. f Could erosion occur as a result of clearing, construction, or use? If so, generally describe. During sediment and in-stream vegetation removal, it is anticipated that some amount of sediment will likely be released into the stream. The sediment release will likely occur after in-channel construction work is complete and the diverted stream flow is reintroduced into freshly exposed stream bed and banks. g. About what percent of the site will be covered with impervious suifaces after project construction (for example, asphalt or buildings)? The project area currently does not contain any impervious surface, and the project will not add any impervious surface. h. Proposed measures to reduce or control erosion, or other impacts to the earth, if any: During construction, erosion will be minimized by implementing appropriate sediment and erosion control best management practices. Measures will include a plan to divert flow from the stream reaches where the sediment and in-stream vegetation will be removed. Diverting the stream around the work area will minimize downstream water quality impacts. The plan will also limit all in-stream work to the summer low flow periods. In areas where invasive vegetation is removed from streams banks and replanted with native vegetation, best management practices will be implemented ( e.g., 7 KING COUNTY ENVIRON-NT AL CHECKLIST .. / May Creek Drainage Improvement Project 2. Air silt fence, coir logs, etc.) to protect the stream during vegetation removal and installation. In the long-term, restoring a buffer of native vegetation will minimize erosion by providing long-term bank stabilization, while maintaining channel flow capacity. In addition, to determine whether there would be a significant erosion impact downstream as a result of the proposed project, King County assessed the pre-project versus post- project percentage of time (over a 60-year period) that erosive flows would cause gravels to erode in the stream channel. The analysis found that, within the accuracy of the model being used, the percentage of time erosive flows occur is virtually unchanged for pre-versus post-project conditions. a. What types of emissions to the air would result from the proposal (i.e., dust, automobile, odors, greenhouse gases, industrial wood smoke) during construction and when the project is completed? If any, generally describe and give approximate quantities if known. Construction of the proposed project may generate some dust during the transport of soil and sediment; however, because the material being transported will be originating from the stream channel and wetland, it will likely be moist, and therefore will have less potential to generate dust. The proposed project, once construction is complete, will emit no gasses with the potential to negatively affect climate change. Construction of the proposed project will use various vehicles and pieces of equipment that emit gasses with the potential to affect climate. These gasses include carbon dioxide (CO2), methane and nitrous oxide, as well as others in much smaller amounts. The global warming potential (GWP) of these compounds is measured in "carbon dioxide equivalents," or C02e, which converts the GWP of various gasses into their equivalent in CO2. The amount ofC02e that may be emitted as a result of constructing the proposed project has been estimated by computing the amount of fuel to be consumed by equipment used to construct the project, both during construction and in transit from King County's Roads Maintenance Headquarters Shops in Renton, where crews and equipment may originate. The actual origin of equipment will not be known until after a contractor is selected. Fuel consumed is then converted into C02e emitted using formulae developed by the Energy Information Administration (EIA) of the U.S. Department of Energy. Using these formulae and estimates, construction of the proposed project will likely result in the discharge of approximately 12 tons of C02e to the atmosphere. b. Are there any off-site sources of emissions or odor that may affect your proposal? If so, generally describe. 8 KING COUNTY ENVIR01',dENTAL CHECKLIST May Creek Drainage Improvement Project No. c. Proposed measures to reduce or control emissions or other impacts to air, if any: 3. Water Greenhouse gas emissions will be controlled during construction by enforcing the King County Vehicle Anti-Idling Policy. In addition, while not specifically proposed as mitigation for greenhouse gas emissions, the emissions will be offset by planting trees and shrubs that are an essential component of the proposed project. Trees and shrubs sequester CO2 during their growth and thus help to offset emissions of CO2 to the atmosphere. The EIA has also developed formulae for estimating the rate of carbon sequestration by various types of trees ( deciduous or coniferous, fast-, medium-, or slow-growing) at various life stages and these formulae have been used to estimate the carbon sequestration potential of the proposed project. Approximately 680 trees will be planted during the planting season following construction of the proposed project. At rates calculated using the above method, these plantings should sequester the 12 tons of C_02e emitted during construction of the proposed project in approximately 6.5 years. These calculations are attached to the checklist. In addition, construction will be performed in accordance with the regulations of the Puget Sound Clean Air Agency, and Best Management Practices for controlling fugitive dust will be utilized as necessary, and may include covering loads during transport and moistening material before transport. a. Swface: 1) Is there any swface water body on or in the immediate vicinity of the site (including year-round and seasonal streams, saltwater, lakes, ponds, wetlands)? If yes, describe type and provide names. If appropriate, state what stream or river it flows into. ( Yes. The proposed project is within or immediately adjacent to May Creek, three small tributaries (Indian Meadow Creek, Long Marsh Creek, Greenes Creek), and one wetland (May Creek #5 in the King County Wetland Inventory). May Creek and its tributaries are Type F Waters ( containing fish or fish habitat) requiring 165 foot buffers under the King County Critical Area Code, and ultimately flow into Lake Washington. Under City of Renton Critical Area Code these streams are considered Class 2 streams (salmonid bearing) and require a 100 foot buffer. 9 KING COUNTY ENVIRON!\uiNTAL CHECKLIST .j May Creek Drainage Improvement Project The May Creek #5 wetland is a large (over 140 acres) riverine wetland that occupies much of the valley floor. Under the King County Critical Area Code this is a Category II wetland with a regulatory buffer of 110 feet. Under the City of Renton Critical Area Code this is a Category I wetland with a standard regulatory buffer width of 100 feet. 2) Will the project require any work over, in, or adjacent to (within 200 feet) the described waters? If yes, please describe and attach available plans. Yes. Excess sediment and invasive reed canarygrass will be removed from the stream channel using a trackhoe or similar equipment. Access to these areas may require crossing the floodplain or wetland. Willows that are obstructing flow will also be removed, but primarily by hand. As mitigation for temporary impacts, any areas that are temporarily disturbed will be restored after construction by planting native vegetation. As mitigation for permanent impacts, a 15-foot buffer of native vegetation (primarily wetland vegetation) will be restored along both sides of the stream bank east of 148th Avenue SE where under existing conditions virtually no natiye vegetated buffer exists. A fence will be installed to protect the new plantings and to minimize livestock access to the stream. This vegetation will increase shade, add habitat, and minimize the return of the reed canarygrass. On the west side of 148th Avenue SE, approximately 3.75 acres of riverine wetland will be enhanced. Off-channel alcoves with large woody debris will also be constructed on the west side of 148th Avenue SE to enhance fish habitat. In addition, natural alluvial fan functions and fish habitat will be potentially restored either at the confluence of May Creek and Long Marsh Creek or at another location with similar opportunity. 3) Estimate the amount of fill and dredge material that would be placed in or removed from surface water or wetlands and indicate the area of the site that would be affected. Indicate the source of fill material. Approximately 4,000 cubic yards of sediment will be removed from May Creek. The removed sediment will either be disposed of appropriately offsite, or will be spread in an approved pasture area adjacent to the project site in coordination with the property owner and as allowed by regulations and permits. As part of the mitigation, a sheet mulch treatment (e.g., cardboard or weed fabric) will be placed within the wetland boundary to shade out reed canarygrass and facilitate planting of native vegetation. Some compost may also be imported to facilitate planting, but the exact amount has not been determined yet. In addition, approximately 76 pieces oflarge woody debris will be placed throughout wetland west of 148th Avenue SE, and approximately _32 10 KING COUNTY ENVJRO\, .. ~ENTAL CHECKLIST May Creek Drainage Improvement Project cubic yards of streambed gravel will be placed near the stream in the off- channel alcoves. Streambed gravel will also be placed at the potentially restored confluence of Long Marsh Creek and May Creek, but the exact quantity at this location has not been determined yet. 4) Will the proposal require surface water withdrawals or diversions? Give general description, purpose, and approximate quantities if known. During the sediment and in-stream vegetation removal, the stream will be temporarily diverted around the work area as part of a temporary erosion and sediment control plan. This diversion may involve using one or more gas- powered pumps to remove water from the channel just upstream of the work area. The water will then be discharged downstream of the work area. Any additional water that seeps into the construction work area may also be removed with a pump as needed. The stream diversion may require fish removal and relocation. All fish removal and relocations will be done by a King County biologist using hand-netting or other accepted methods. No other surface or groundwater will be withdrawn or diverted. 5) Does the proposal lie within a 100-year floodplain? If so, note location on the site plan. Yes. The project area lies within the I 00-year floodplain for May Creek. 6) Does the proposal involve any discharges of waste materials to surface waters? If so, describe the type of waste and anticipated volume of discharge. No waste material will be discharged to surface or groundwater. b. Ground: J) Will ground water be withdrawn, or will water be discharged to ground water? Give general description, purpose, and approximate quantities if known. No. This project will not withdraw from or discharge to groundwater. 2) Describe waste material that will be discharged into the ground from septic tanks or other sources, if any (for example: Domestic sewage; industrial, containing the following chemicals ... ; agricultural; etc.;.' Describe the general size of the system, the number of such systems, the number of houses to be served (if applicable), or the number of animals or humans the system(s) are expected to serve. No waste material will be generated or discharged into the ground. II KING COUNTY ENVIRONlhtsNTAL CHECKLIST .. ,/ May Creek Drainage Improvement Project c. Water runoff (including stormwater): 1) Describe the source of runoff (including storm water) and method of collection and disposal, if any (include quantities, if known). Where will this water flow? Will this water flow into other waters? Jfso, describe. · Any areas that are temporarily disturbed during construction have the potential to generate sediment-laden stormwater runoff. Temporary erosion and sediment control best management practices, such as silt fences, turbidity curtains, or coir logs, will be used to prevent sediment-laden stonnwater runoff from entering the stream or wetlands. As needed, additional best management practices may include collecting sediment-laden stormwater before it enters the stream or wetland and discharging the stormwater into a vegetated upland location instead. Water quality monitoring will be conducted during construction to ensure that state water quality standards are met. If water quality standards are exceeded, additional best management practices will be implemented to protect water quality. 2) Could waste materials enter ground or surface waters? If so, generally describe. No. All sediment excavated from the stream will be disposed of at an approved offsite location, or will be spread in an approved location adjacent to the project site in coordination with the property owners and as allowed by regulations and permits. It will not be allowed to enter ground or surface waters. d. Proposed measures to reduce or control surface, ground, and runoff water impacts, if any: During construction, temporary erosion and sediment control best management practices, such as silt fences, turbidity curtains, or coir logs, will be used to prevent any material or runoff from entering ground or surface water during construction. Construction equipment access will also be limited to specific locations along the stream, which will minimize disturbance to existing vegetation. In the long-term, the purpose of this project is to reduce the duration of flooding in May Valley at both the start and end of the rainy season by removing in-stream channel obstructions. This effort should help alleviate the duration of localized flooding on adjacent properties during low to moderate storm events. The project hydraulic analysis found that the potential for erosion downstream of May Valley is virtually unchanged for the pre-versus post-project conditions. 12 KING COUNTY ENVIROJ,.,,fENTAL CHECKLIST May Creek Drainage Improvement Project 4. Plants a. Check or circle types of vegetation found on the site: 0 Deciduous Tree: alder, cottonwood, Oregon ash, maple, aspen, other -cherry 0 Evergreen Tree: fir, cedar, pine, other -spruce [gj Shrubs: willow, dogwood, hardback, Indian plum 0 Grass: reed canarygrass 0 Pasture: various grasses D~m~: , [gj Wet Soil Plants: cattail, buttercup, soft rush, bulrush, skunk cabbage, other -horsetail D Water Plants: water lily, eelgrass, milfoil, other 0 Other types of vegetation: blackberry b. What kind and amount of vegetation will be removed or altered? Approximately 3,000 square feet of reed canarygrass will be removed from the stream banks. Approximately 5,500 square feet of flow obstructing willows will also be removed from the stream channel to improve flow conditions. In addition, approximately five acres of reed canarygrass will be removed adjacent to the channel and in the wetland and will be replanted with native vegetation. This reed canarygrass will be removed by placing a sheet mulch treatment, such as cardboard or weed fabric, over the grass to shade out the grass over multiple growing seasons. The native vegetation will be planted through this treatment. c. List threatened or endangered plant species known to be on or near the site. No threatened or endangered plant species are currently known to be on or near the project site; however, historically, threatened or endangered plant species were known to exist in the area. According to the Washington Department of Natural Resources Washington Natural Heritage Program Database (June 2009), Tall Bugbane (Cimicifaga elata) existed historically in the project area but is not likely to be present any longer because it typically grows along the margins of mature or old growth stands of coniferous or mixed coniferous-deciduous forest . This type of habitat no longer exists in the project area. In addition, Tall Bugbane was not identified in the project study area during any of the wetland or stream surveys which spanned multiple days in January, February, and August 2010. 13 KING COUNTY ENVIRONhi"NTAL CHECKLIST .,/ May Creek Drainage Improvement Project d. Proposed landscaping, use of native plants, or other measures to preserve or enhance vegetation on the site, if any: This project proposes to enhance five acres of native vegetation along the stream corridor and in the wetland. Invasive reed canarygrass will be removed along the stream and in the wetland, and the area will be replanted with native vegetation. 5. Animals a. Circle any birds and animals which have been observed on or near the site or are known to be on or near the site: 18:J Birds: hawk, heron, eagle, songbirds, other: ducks 18:J Mammals: deer, bear, elk, beaver, other: coyote 18:J Fish: bass, salmon, trout, herring, shellfish, other b. List any threatened or endangered species known to be on or near the site. Terrestrial Species Red-tailed hawks (Buteo jamaicensis), bald eagles (Haliaeetus leucocephalus), and great blue herons (Ardea herodias) have been observed traveling through the project area; however, according to the Washington Department of Fish and Wildlife Priority Habitat and Species Database (June 2009) there are no documented or known nesting sites associated with these species in the project area. Great blue herons and bald eagles are both species of concern in Washington State (WDFW 2010), but are not threatened or endangered. Aquatic Species Historically, May Creek supported five species of salmonids: Chinook ( Oncorhynchus tshawytscha), sockeye (0. nerka), and coho (0. kisutch) salmon, as well as rainbow/steelhead (0. mykiss) and cutthroat (0. clarki) trout (King County 1995). Salmon still use May Creek and its tributaries even though their numbers have decreased (King County 1995). Chinook and sockeye salmon are found in the lower reaches of May Creek and in May Canyon; but they most likely do not travel upstream into May Valley as far as the project area (King County 1995). Both of these species are species of concern in Washington State (WDFW 2010), and Chinook salmon is listed as threatened under the federal Endangered Species Act. Coho salmon and rainbow/steelhead and cutthroat trout rear in May Valley and use it as a travel corridor to upstream spawning habitat in the North Fork, Cabbage and Country Creeks, and Tributary 0291 A (King County 1995). Under the federal Endangered 14 KING COUNTY ENVIROh,.iENTAL CHECKLIST May Creek Drainage Improvement Project Species Act, steelhead are listed as a threatened species, and coho salmon are a species of concern. In addition, the Lake Washington Basin contains spawning populations of the federally- listed threatened bull trout (Salvelinus conjluentus), but no spawning populations have been confirmed in the part of the basin where the project is located (WDFW 1998, 2004a). Furthermore, it is unlikely bull trout will be present in May Creek due to a lack of suitable habitat. Under the federal Endangered Species Act, no designated or proposed critical habitat for Chinook salmon, steelhead, or bull trout is located within the project area. An effects determination for species protected under Section 7 of the Endangered Species Act will be completed in coordination with the appropriate federal agencies during the permitting process. This determination will analyze potential impacts to listed species resulting from the project. c. Is the site part of a migration route? If so, explain. Yes. Anadromous fish, including coho salmon, rainbow/steelhead and cutthroat trout, use the May Valley as a migration corridor to upstream spawning habitat. Most of the large valleys in ](jng County, including May Valley, comprise a portion of the Pacific Flyway used by waterfowl and other migratory bird species during spring and fall migration. d. Proposed measures to preserve or enhance wildlife, if any: Best management practices will be utilized during construction to minimize potential impacts to listed species. For example, in-water construction work will be completed during the summer low flow work window that is designated to protect listed aquatic species. Species are unlikely to be present in the project area during the designated summer work window. Temporary erosion and sediment control measures (discussed in section 3.c above), including a stream diversion, will also be implemented to protect water quality. The stream diversion may require fish removal and relocation. All fish removal and relocations will be done by a ](jng County biologist using hand-netting or other accepted methods. In the long-term, this project will enhance fish and wildlife habitat in May Valley by restoring approximately five acres of native wetland and riparian vegetation, adding large woody debris to off-channel alcoves, and potentially restoring fish habitat and alluvial fan functions at the confluence of Long Marsh Creek and May Creek. This will increase the complexity and diversity of habitat available in the project area. 15 KING COUNTY ENVIRONl\'u,NTAL CHECKLIST ... / May Creek Drainage Improvement Project 6. Energy and Natural Resources a. What kinds of energy (electric, natural gas, oil, wood stove, solar) will be used to meet the completed project's energy needs? Describe whether it will be used for heating, manufacturing, etc. None. The completed project will not require any energy. b. Would your project affect the potential use of solar energy by adjacent properties? If so, generally describe. No. c. What kinds of energy conservation features are included in the plans of this proposal? List other proposed measures to reduce or control energy impacts, if any: None are proposed. 7. Environmental Health a. Are there any environmental health hazards, including exposure to toxic chemicals, risk of fire and explosion, spill, or hazardous waste, that could occur as a result of this proposal? If so, describe. No toxic chemical or hazardous waste will be used or generated by this project. I) Describe special emergency services that might be required. None. 2) Proposed measures to reduce or control environmental health hazards, if any: Maintenance and refueling of construction equipment will occur outside of the stream, wetland, and buffer areas. b. Noise I) What types of noise exist in the area which may affect your project (for example: traffic, equipment, operation, other)? Some minor traffic noise from adjacent roads is expected, but it will have no effect on construction or on the completed project. 16 KING COUNTY ENVIR01'.1vlENT AL CHECKLIST May Creek Drainage Improvement Project 2) What types and levels of noise would be created by or associated with the project on a short-tenn or a long-tenn basis (for example: traffic, construction, operation, other)? Indicate what hours noise would come from the site. During construction, equipment operation will temporarily increase noise levels in the vicinity. Construction equipment may produce temporary noise levels as high as 90 decibels. The completed project will not change existing noise levels. 3) Proposed measures to reduce or control noise impacts, if any: Construction activities will comply with provisions of the King County Noise Ordinance (Ordinance No. 3139). Equipment operation will be limited to the hours of7 a.m. and 7 p.in., Monday through Friday. 8. Land and Shoreline Use a. What is the current use of the site and adjacent properties? The current use of the site is a combination of rural residential with small farms and undeveloped open space. The small farms in the project area primarily consist of pastures that are utilized by horses. b. Has the site been used for agriculture? Jfso, describe. Yes. May Valley supports pasture and low0 intensity agriculture uses, small farms, and scattered single-family residences; however, the project area is not located in an Agriculture Production District. Historically, May Valley was probably more extensively utilized for agriculture production; however, under existing conditions the pastures in the project area are primarily utilized only by horses. c. Describe any structures on the site. The adjacent properties contain single-family homes, barns, and other out-buildings. None of these structures will be affected by construction of the proposed project. d. Will any structures be demolished? If so; what? No. e. What is the current zoning classification of the site? The current zoning classification is RA-5 and RA-10, rural residential with future development limited to rural uses with maximum densities of one house per five aces and ten acres, respectively. 17 KING COUNTY ENVIRON1,.isNT AL CHECKLIST •,,,, May Creek Drainage Improvement Project f What is the current comprehensive plan designation of the site? The current comprehensive plan designation is rural residential. g. If applicable, what is the current shoreline master program designation of the site? Not applicable. May Creek is not a Shoreline of the State in the project area and therefore, is not regulated under the King County Shoreline Master Program. h. Has any part of the site been classified as an "environmentally sensitive" area? Jfso, specify. Yes. The proposed project will occur in and adjacent to May Creek and its tributaries, which are Type F Waters (contains fish or fish habitat) under the King County Critical Area Code. The proposed project is also located in the I 00-year floodplain for May Creek. In addition, a large Category II Wetland (May Creek #5) covers a large percentage of the May Valley floor. The proposed work will all occur within the stream, wetland, buffers, and floodplain of May Creek.· i. Approximately how many people would reside or work in the completed project? None. j. Approximately how many people would the completed project displace? None. k. Proposed measures to avoid or reduce displacement impacts, if any: Does not apply. 1. Proposed measures to ensure the proposal is compatible with existing and projected land uses and plans, if any: One of the project goals is to reduce the duration of flooding on properties adjacent to May Creek. Reducing floodwaters on these properties will facilitate the continued use of these properties as single-family homes with small farms. 18 KING COUNTY ENVIRO:t-.,..ENTAL CHECKLIST May Creek Drainage Improvement Project 9. Housing a. Approximately how many units would be provided, if any? Indicate whether high, middle, or low-income housing. Does not apply. b. Approximately how many units, if any, would be eliminated? Indicate whether high, middle, or low-income housing. Does not apply. c. Proposed measures to reduce or control housing impacts, if any: Does not apply. 10. Aesthetics a. What is the tallest height of any proposed structure(s), not including antennas; what is the principal exterior building material(s) proposed? Does not apply. No buildings or structures will be constructed. b. What views in the immediate vicinity would be altered or obstructed? None. c. Proposed measures to reduce or control aesthetic impacts, if any: Does not apply. 11. Light and Glare a. What type of light or glare will the proposal produce? What time of day would it mainly occur? · None. b. Could light or glare from the finished project be a safety hazard or interfere with views? No. 19 KING COUNTY ENVIRON1-.t<:NT AL CHECKLIST . ../ May Creek Drainage Improvement Project c. What existing off-site sources of light or glare may affect your proposal? None. d. Proposed measures to reduce or control light and glare impacts, if any: Does not apply. 12. Recreation a. What designated and informal recreational opportunities are in ihe immediate vicinity? Recreational opportunities in the immediate project area are limited; however, they could include fishing, hiking, bicycling, and/or bird watching. Within a couple of miles of the project area, the King County Cougar Mountain Park and the Squak Mountain State Park together . provide over 5,000 acres of public land with trails for hiking and horseback riding. b. Would the proposed project displace any existing recreational uses? If so, describe. No. All of the proposed work will occur on private property and will not affect recreational opportunities or access. c. Proposed measures to reduce or control impacts on recreation, including recreation opportunities to be provided by the project or applicant, if any: No measures proposed. 13. Historic and Cultural Preservation a. Are there any places or objects listed on, or proposed for, national, state, or local preservation registers known to be on or next to the site? If so, generally describe. The Washington State Department of Archaeology and Historic Preservation and the King County Cultural Resource Protection Project databases were checked on March 1, 2010. No listed or proposed historic properties or archaeological sites were found in the project vicinity. b. Generally describe any landmarks or evidence of historic, archaeological, scientific, or cultural importance known to be on or next to the site. None are known to be present. c. Proposed measures to reduce or control impacts, if any: 20 KING COUNTY ENVIR0\-,,;1ENTAL CHECKLIST May Creek Drainage Improvement Project Because there are not any listed or proposed archaeological or historic resources in the project area, no mitigation is being proposed. If, archaeological or historic resources are uncovered or encountered during project construction, work will cease inunediately, and appropriate steps necessary to protect those resources will be taken before construction resumes. If resources are discovered, the Washington State Department of Archaeology and Historic Preservation, the King County Historic Preservation Program, and any affected federally recognized tribes will be notified immediately, and an on-site inspection will be conducted by a professional archaeologist and other qualified resource professionals. A mitigation plan would then be prepared before resuming construction at the site of discovery, if necessary. In addition, the measures and the possibility of uncovering materials of archaeological or historic significance near inland waters will be discussed during a preconstruction conference with the construction crew/contractor before performing the work on-site. 14. Transportation a. Identify public streets and highways serving the site, and describe proposed access to the existing street system. Show on site plans, if any. Access to the site will be from properties located on SE May Valley Road or 148th A venue SE. b. Is site currently served by public transit? If not, what is the approximate distance to the nearest transit stop? Does not apply. c. How many parking spaces would the completed project have? How many would the project eliminate? Does not apply. d. Will the proposal require any new roads or streets, or improvements to existing roads or streets, not including driveways? If so, generally describe (indicate whether public or private). No new roads will be required. e. Will the project use (or occur in the immediate vicinity of) water, rail, or air transportation? If so, generally describe. No. 21 KING COUNTY ENVIRONIWl<:NT AL CHECKLIST May Creek Drainage Improvement Project f How many vehicular trips per day would be generated by the completed project? If known, indicate when peak volumes would occur. None. g. Proposed measures to reduce or control transportation impacts, if any: Does not apply. 15. Public Services a. Would the project result in an increased need for public services (for example: fire protection, police protection, health care, schools, other)? If so, generally describe. No. b. Proposed measures to reduce or control direct impacts on public services, if any. Does not apply. 16. Utilities a. Circle utilities currently available at the site: electricity, natural gas, water, refase service, telephone, sanitary sewer, septic system, other. Does not apply. b. Describe the utilities that are proposed for the project, the utility providing the service, and the general construction activities on the site or in the immediate vicinity which might be needed. Does not apply. 22 • KING COUNTY ENVIRONMENTAL CHECKLIST May Creek Drainage Improvement Project C. SIGNATURE The above answers are true and complete to the best of my knowledge. I understand that the lead agency is relying on them to make its decision. Signature: Name: Title: Date: Mana~nJ En~neer. Department ofTranspotiation, Road Services Division, Environmental Unit ~ r 2,._l 10 The following are included with the Checklist if checked off: ~ Vicinity Map ~ Greenhouse Gas Worksheet D Project Plans 2J May Creek Drainage Improvement Project (9A 1205) Legend 0 Project Area Limits City Boundaries o River Miles The nfonnalio!l lrd.lded on Nr; rnep ha been complad by King County 5laff from a variety of IIOtl"OIIII and Is sub)8cl lo mange wllhout nolioe. King Olulty makes no represenlmlons « wamintl88, 8JCP"ISS « Implied, aa to accuracy, compleleness, Urnellroess, or rights lo lhe UM of &Ud1 lnfolmallon. This dorument ls nol lnlendec:I f<:r use aa I ISUl'VeY producl. l<Jng County &h8I not be liable for any genenil, special, Indirect, ~I, or eons~nllal dameges kd.ldlng, but rool Hrrilllld lo, loll revenuea or lost profits resulUng from Iha use or misuse of Iha lnfoonallon QOntalned on 11113 map. /vl'j sale of 1h11 m11p « Information on 1h11 map ia prohlbllEld -~.'t except by Mitten penris9lon of King County. ?~\<!., - ' --2......-' Greenhouse Gas (GHG) Emissions Worksheet Project Name: IVlay Creek Drainage Improvement Project (9A1205) Note: The finished project will emit no GHGs aside form those occuring in the environment by natural processes. All emissions are therefore related to construction of the proposed project. Distance of project site from Renton Shops, where most daily construction-related vehicle trips will start and end: Estimated days of construction activity: '-'i 1-"0 __ ___, Rate Miles/ (mpg or 3.75 miles Em. Coe!. (lbs C02e/ Emissions Vehicle hours gal/hr*) Fuel Used gal) (lbs C02e) Tons C02e Pickup 40 20.7 1.93 19.564 37.80 0.02 Pickup 40 20.7 1.93 19.564 37.80 0.02 Dump Truck 160 6.15 26.02 22.384 582.35 0.29 Dump Truck 160 6.15 26.02 22.384 582.35 0.29 PC 120 Trackhoe 160 6.3 1008.00 22.384 22563.07 11.28 Heavy Equip Transport 40 1.9 21.05 22.384 471.24 0.24 Lo9 Truck 16 1.9 8.42 22.384 188.50 0.09 TOTAL: 24463.12 12.23 Carbon Sequestration Approximately 680 trees will be planted as part of this project. Of these, 340 as classified as fast- growing hardwoods, and the remaining 340 as moderate-growing conifers. The carbon sequestration rates of these trees was calculated using data tables from the U.S. Department of Energy, Energy Information Administration. Using these data tables, the proposed plantings (assuing an 80% survival rate) will sequester 10.9 tons of carbon after 6 years and 14.0 tons after 7 years. • City of Renton Planning Division FEB I 2 iulJ May Creek Drainage Improvement Project (9A1205) King County Water and Land Resources Division Stream and Wetland Impact Analysis and Mitigation JPlan Prepared by: · King County Road Services Division Lindsey Miller, Environmental Engineer Erick Thompson, Senior Environmental Engineer King County Water and Land Resources Division Doug Chin, Supervising Engineer Prepared for: King County Department of Natural Resources and Parks Water and Land Resources Division 201 South Jackson Street Seattle, WA 98104 Revised September 2011 !EXHIBIT 13 0 0 d D 0 0 0 0 O' 0 0 0 0 0 0 D 0 lo I 0 May Ciree~ Clhla1n11l1le~ Restoiratooll1l rPiro]ect King County Water and Land Resources Division Prepared for: King County Department of Parks and Natural Resources Water and Land Resources Division 201 South Jackson Street Seattle, WA 98104 Prepared by: Lindsey Miller, Environmental Engineer Cindy Clark, Environmental Engineer Todd Martin, Environmental Engineer King County Road Services Division City of Renton Planning Division FEH 1 2 LU13 Environmental Unit March 10, 201 O !EXHIBIT 14 ~aiy Cnee~ C~a11nurue~ IFRestcu-ait~oi1n1 !Pu-eject King County Water and Land Resources Division C ~ ty (Q) ff !FR e 1n1 ft (Q) 1n1 We ft~ cdl 1n1 tdl IR cdl ft~ 1n1 9l Addendum to Wetland Delineation Report Dated March 10, 2010 . Prepared for: King County Department of Parks and Natural Resources Water and Land Resources Division 201 South Jackson Street Seattle, WA98104 Prepared by: Cindy Clark, Environmental Engineer King County Road Services Division Environmental Unit November 17, 201 O Citv of Renton PlanninD Division_ FEB l 'i , .J:, !EXHIBIT 15 ) CITY OF RENTON WETLAND RATING This document is an addendum to the May Creek Channel Restoration Project Wetland Delineation Report prepared by King County Road Services Division, Environmental Unit, dated March 10, 2010. The wetland delineation report described a large riverine wetland (total size approximately 140 acres) along a section of May Creek in southeastern King County near the cities of Renton and Newcastle. The project study area is located between River Mile (RM) 4.3 and 4.8 of May Creek, and included approximately 25 acres of the wetland complex (referred to as May Creek #5 in the King County Wetland Inventory (1990)). The purpose of the wetland delineation was to identify the wetland boundary on the properties adjacent to May Creek where potential project impacts may occur. To determine the required buffer width, the wetland was also rated, using criteria referenced in the King County Critical Area Code (KCC 21A.318). King County adopts the Washington State's Department of Ecology: Washington State Wetland Rating System for Western Washington (Hruby 2004). May Creek #5 was determined to be a Category II riverine wetland with a 110 foot buffer, located in the natural 100-year floodplain of May Creek. However, the portion of the study area/wetland that lies west of 148th Ave SE lies within the City of Renton jurisdiction, and therefore must also be classified using those criteria. The wetland, when rated using the City of Renton classification system, is a Category 3 wetland with a 25-foot buffer. TI1e wetland is not a Category I wetland because it does not meet any of the following criteria: a. The presence of species listed by the Federal or State government as endangered or threatened, or the presence of essential habitat for those species; and/or b. Wetlands having forty percent (40%) to sixty percent (60%) permanent open water (in dispersed patches or otherwise) with two (2) or more vegetation classes; and/or c. Wetlands equal to or greater than ten ( 10) acres in size and having three (3) or more vegetation classes, one of which is open water; and/or d. The presence of plant associations of infrequent occurrence; or at the geographic limit of their occurrence The wetland is not a Category 2 wetland because it does not meet any of the following criteria: a. Wetlands that are not Category I or 3 wetland; and/or b. Wetlands that have heron rookeries or osprey nests, but are not Category 1 wetlands; and/or c. Wetlands of any size located at the headwaters of a watercourse, i.e., a wetland with a perennial or seasonal outflow channel, but with no defined influent channel, but are not Category 1 wetlands; and/or d. Wetlands having minimum existing evidence of human-related physical alteration such as diking, ditching or channelization 2 The wetland is a Category 3 wetland because it meets criteria in (a): a. Wetlands that are severely disturbed. Severely disturbed wetlands are wetlands which meet the following criteria: 1. Are characterized by hydrologic isolation, human-related hydrologic alterations such as diking, ditching, channelization and/or outlet modification; and 2. Have soils alterations such as the presence of fill, soil removal and/or compaction of soils; and 3. May have altered vegetation Criteria (b) and (c) under the Category 3 classification include newly emerging wetlands and all other wetlands not classified as a Category 1 or 2. These are not applicable since criteria defined in (a) are met. The hydrology within the wetland is partly controlled by May Creek, which has been channelized in the past. On the north side of the wetland, the wetland boundary closely follows a line of fill that appears to have been placed in wetland areas over the years to facilitate farm use. On the south side of the wetland, the wetland boundary more closely follows the natural valley topography. The wetland has also been degraded over the years by adjacent farming and agricultural uses. Many areas of the wetland are actively mowed and used for grazing horses and other livestock. The wetland received a higher rating based on the King County and Washington State classification system, and has a larger buffer under that system (110 feet versus 25 feet with the City of Renton rating). The more conservative King County rating and buffer will be used when calculating project impacts and mitigation. 3 IBASEl~NE SlR!EAM CONlD~l~ONS MAY CRIE!Ert( DIRA~NAGIE ~MPROVEMIENl C~P#SlA 1205 Revosed !December 2, 201 O King County Prepared by: Erick Thompson Environmental Scientist III and Kerry Bauman ' Environmental Scientist III Department of Transportation Roads Services Division Environmental Unit 20 I South Jackson Street, Suite 200 Seattle, Washington 98104 Yr rte, paq (J t J ',V · p~(I v-qo rt -r f l10rl)7 · City ot Renton Planning Division FEB I 2 2013 !EXHIBIT 16 0 0 D 0 0 0 0 0 ~ a u 0 [) 0 0 0 0 0 0 MAY CREEK SEDIMENT TRANSPORT STUDY REPORT Prepared for King County Department of Natural Resources and Parks 201 S. Jackson Street, Suite 600 Seattle, WA 98104-3856 · Prepared by Anchor QEA, LLC 1605 Cornwall Avenue Bellingham, WA 98225 June 2009 EXHIBIT 17 n MAY CREEK EROSION STABILIZATION DRAFT REPORT MAY CREEK SEDIMENT TRANSPORT STUDY PHASE 3 Prepared for King County Department of Natural Resources and Parks 201 Jackson Street, Suite 600 Seattle, Washington 98104 Prepared by Anchor QEA, LLC 1605 Cornwall Avenue Bellingham, Washington 98225 January 2010 IEXHXBIT 18 0 0 0, ~] 0 0 0 0 0 0 0 ~ 0 8 0 0 0 0 i 0 • Hy cdl IT' aH\.n ~ o (C a1 iro cdl Hy cdl IT'© ~ © g o c Airoai~yses ©lf ~!he Maiy CCiree~ CC lh1 ai iro iro e ~ IR es it© ir ai it o © iro IP' ir © j e cit December 17, 2010 ~· King County Department of Natural Resources and Far~ Water and Land Resources Oivlsion Science Section King Street Center, KSC-NR-0600 lOl south Jackson Street, Suite 600 Seattle, WA 98104 Alternate Formats Available 206-296-7380 TTY Relay: 711 !EXHIBIT 19 0 Q 0 0 D a 0 q [J ' -· [] ' . '·- " . . ; ' ~ Biological Evaluation Report foir: Chinook Salmon and Steelhead Trout as protected under the Endangered Species Act May Creek, King County, Washington State Prepared for: ' King County Water and Land Resources Division Department of Natural Resources and Parks 201 South Jackson Street Ste 600 Seattle, WA 98104-3856 Phone number: (206) Prepared by: Mistie Hammer King County Road Services Division February 2011 1i·11G-r7~e ~ 711·p~~tn+ f MIP7 ~c:J,·~H'>· IEXHIBXT 20 ~ 0 0 0 0 0 0 0 0 0 0 0 a 0. [l ~ King County • Department of Transportation Road Services Division Engineering Services Section Environmental Unit King Street Center 201 South Jackson Street Seattle, WA 98104-3856 (206) 296-6520 Fax (206) 296-0567 TTY Relay: 711 www.metrokc.gov February 9, 2011 City of Renton Planning Division FEB 1 2 ,uil TO: Doug Chin, Senior Engineer, Water and Land Resources Division, Department of Natural Resources and Parks FM: Julia Tumey, L.G., Environmental Engineer, Environmental Unit, Road Services Division, Department of Transportation and Jeff Burkey, Hydrologist, Water and Land Resources Division, Department of Natural Resources and Parks RE: May CreekDrainage Improvement Project: SE May Valley Road and 148th A venue SE -Sediment Assessment Introduction This memo provides information on sediment conditions in May Creek from approximately 148'h Avenue SE upstream to 164th Avenue SE. This evaluation addresses geomorphologic controls, sediment sources, sediment behavior in the drainage and how the project actions are likely to influence future sedimentation in May Valley. The purpose of the following background evaluation is to provide information to assist King County Department of Natural Resources and Parks, Water and Land Resources Division in the design process for a drainage improvement project in May Valley. The proposed project location is shown in Figure I. Two questions have been rais~d regarding sediment associated with the May Valley drainage improvement project: Question 1: Will the project change sediment delivery downstream to May Creek? Question 2: After the proposed drainage improvement project and mitigation on May Creek in May Valley, will sediment refill the May Valley project area? EXHIBIT 21 E3 D D 0 0 0 D D 0 D D 0 0 D [] ~ King County Department of Transportation Road Services Division Engineering Services Section King Street Center 201 South Jackson Street Seattle, WA 98104·3856 August 4, 2011 City of Renton Planning Division FEB 1 2 2013 TO: Don Althauser, Managing Engineer, Water and Land Resources Division, Stormwater Services Section FM: Bill Kerschke, Environmental Scientist, Road Services Division, Engineering Services Section · ~ Julia Turney, Environmental Engineer, Road Services Division, Enginee~ · O Services Section RE: May Creek Drainage Improvement Project (9AI205) Post-Construction Erosion Monitoring Plan • Downstream of 148th Avenue SE Introduction This memo was prepared to address comments from the Washington Department of Ecology and the public on the May Creek Drainage Improvement Project. This memo describes the post-construction erosion monitoring plan for the reach of May Creek downstream of 148th Avenue SE. Project components, including in-stream sediment and vegetation removal between mile 4.3 and 4. 9 of May Creek, have raised public concern that properties downstream of 148th Avenue SE may be impacted by post-project changes in stream bed and/or bank erosion. Btudies already completed by King County Water and Land Resources indicate that the project will not effect downstream erosion (WRLD); however, King County is committed to confirming this assertion post-project. The intent of this memo is to describe an approach for a post-construction monitoring that will evaluate project-related changes in erosion in May Creek between I 48th Avenue SE and the Coal Creek Parkway SE. This reach is often referred to as the "canyon reach" of May Creek. Background Studies Studies were completed to evaluate downstream impacts for the proposed May Creek project. A sediment transport study (Anchor 2009) was implemented to analyze the erosion threshold in May Creek between 148th Avenue SE and Coal Creek Parkway SE. This study included selection of a study reach, data: collection, analysis, preparation of a HEC-RAS model of the reach, and evaluation of the discharge at which the bed sediment begins to move. According to the sediment mobility evaluation, the threshold of motion occurs between approximately 70 to 350 cubic feet per second (cfs). !EXHIBIT 22 May Creek Drainage Improvement Project (9A1205) Construction Water Quality Protection and Monitoring Plan Federal Project NWP-210"158 King County Department of Natural Resources and Parks Water and Land Resources Division Revised September 7, 2011 · Table of Contents FEB 1 2 iuJJ I. Plan Purpose ............................................................................................................... 1 2. Water Quality Criteria ................................................................................................ 1 3. Monitoring Plan .......................................................................................................... 2 4. Water Quality Protection Measures ................................................ , ........................... 4 Figure I: May Creek Water Quality Sampling Locations During Construction ................ 7 1. · Plan Purpose In order to ensure that construction of the May Creek Drainage Improvement Project does not exceed water quality standards as established by federal, state, and local laws and regulations, the King County Water and Land Resources Division has developed this plan for in-stream water quality protection and monitoring during construction. Specifically, water quality criteria contained within Washington Administrative Code f:N AC) I 73-201A-030(2), I 73-201A-040, and l 73-201A-l 10(3) apply to this project. The project is located in May Creek (WRIA 08-0282) and the surrounding wetland on the south side of SE May Valley Road between approximately River Mile 4.3 and 4.9 (Figure 1). Construction activities consist ofremoving accumulated sediment and flow obstructing vegetation (primarily reed canarygrass and willow) from May Creek, reconstructing the confluence of Long Marsh Creek and May Creek, and planting riparian and wetland vegetation as compensatory mitigation. The purpose of the monitoring plan is to ensure that silt and sediment generated by project construction activities does not affect water quality in violation of project permits and applicable regulations. Erosion control best management practices (BMPs) are proposed and will be implemented to protect water quality within May Creek. Water quality monitoring will be performed to confirm the effectiveness of the BMPs. 2. Water Quality Criteria Washington State WAC l 73-201A establishes criteria for surface waters of the state. The Department of Ecology may allow a temporary area of mixing during and immediately after necessary in-water construction activities that result in the disturbance of in-place sediments. This temporary area of mixing is subject to the constraints of WAC l 73-201A-200(l)(e)(i) and can occur only after the activity has received all other May Creek Drainage Impro,. ..nt Project (9A 1205) Water Quality J. ~cion and Monitoring Plan necessary local and state permits and approvals, and after the implementation of appropriate best management practices to avoid or minimize disturbance of in-place sediments and exceedances of the turbidity criteria. Summer low flows in May Creek and Long Marsh Creek are below IO cfs (the annual mean flow in May Creek is 8.6 cfs) and therefore the point of compliance for the temporary area of mixing shall be 100 feet downstream from the construction activity per WAC 173-201A-200(l)(e). Turbidity Turbidity will be monitored for this project per WAC l 73-201A-200(1)(e). At the point of compliance, turbidity shall not exceed: o 5 NTU over background when the background is 50 NTU or less; or o A 10 percent increase in turbidity when the background turbidity is more than SONTU. Other Parameters Dissolved oxygen, the 7-day average of the daily maximum temperatures (7-DADMax), and pH will not be momtored for this project because the construction activities are not expected to affect these parameters. 3. Monitoring Plan Sampling Locations The following sampling points (SP) (Figure 1) will be used for monitoring. Because this is a linear project that extends for approximately 2,000 feet, and multiple stream bypasses will be needed, the sampling points in May Creek will change as the project proceeds. o SPl (upstream location): Samples will be taken in May Creek 100 feet upstream of the work area before construction begins and will continue to be taken at the same time as the point of compliance samples (SP3) during the construction activities. o SP2 (upstream location): During work at the Long Marsh Creek confluence, Samples will be taken in Long Marsh Creek 100 feet upstream of the work area before construction begins and will continue to be taken at the same time as the point of compliance samples (SP3) during the construction activities. o SP3 (downstream point of compliance): Samples will be taken in May Creek I 00 feet downstream of the work area before construction begins (to establish baseline conditions) and will continue during construction activities. Additional sampling points may be used on an as needed basis. 2 May Creek Drainage lmprc .nent Project (9Al205) Water Quality . .ection and Monitoring Plan Sampling Frequency Immediately prior to in-water work, baseline sampling will be performed at SP 1, SP2, and SP3 in order to obtain representative values for background water quality in the stream. Once construction activity has commenced in an area, water quality data will be collected at each sampling point using a water monitoring device. The monitoring device will be used to collect data every 15 minutes during the construction period. Monitoring will not be performed when the contractor is not working (typically evenings, weekends and holidays). For water quality monitoring purposes, "final stabilization" is defined in the Construction Stormwater General Permit as "the establishment of a permanent vegetative cover, or equivalent permanent stabilization measures (such as riprap, gabions or geotextiles) which prevents erosion. Once the project has implemented the final stabilization measures, the likelihood that it will contribute sedimentation to the stream is small; therefore, monitoring will no longer be necessary. Field Sampling and Analysis Procedures To evaluate the state water quality criteria, samples will typically be taken in-stream using a YSI, a Hach 21 OOP turbidimeter, or other equivalent monitoring device. The monitoring device will be calibrated and operated in accordance with the manufacturer's specifications. During all sampling, care will be taken to not disturb the streambed or bank, which could contaminate the samples. Samples will be taken in approximately the middle of the stream, at mid-depth. · During construction activities that have the potential to affect turbidity, King County staff will be onsite to collect and review water quality data. If the data being collected indicate that state water quality standards are being exceeded, the project's Certified Erosion Control and Sediment Lead (CESCL) will immediately be contacted. The contractor will be directed to stop work while the reason for non-compliance is determined. If the non-compliance is due to construction activities, the contractor will be directed to take the following potential corrective measures before being allowed to resume work: o Immediate maintenance of existing erosion control facilities o Implementation of additional erosion control measures o Diversion of any stormwater away from exposed areas o Suspension of all work activities until more favorable conditions exist The contractor will determine which contingency measures should be implemented and will submit the proposal to the CESCL for review and approval. Once the contingency measures have been implemented, King County staff will monitor water quality to ensure that compliance with water quality standards have been achieved. The CESCL will 3 May Creek Drainage Improv, ,nt Project (9Al205) Water Quality P, tion and Monitoring Plan document corrective measures taken in the project's Stormwater Pollution and Prevention Plan (SWPPP). Monitoring Personnel King County Water and Land Resources Division will provide staff to perform water quality monitoring. Long-term Data Storage and Reporting All water quality monitoring data collected during construction will be recorded electronically and downloaded into an excel spreadsheet later in the office by project staff. Ifno exceedances are detected, the results of the water quality sampling should be sent on a monthly basis to Rebekah Padgett at Washington Department of Ecology. If any exceedance is detected it should be reported to Washington Department of Ecology within 24-hours with the following information: a. A description of the nature and cause of exceedance. b. The period of non-compliance, including exact dates, duration, and times and/or the anticipated time when the Applicant will return to compliance. c. The steps taken, or to be taken, to reduce, eliminate, and prevent recurrence of the non-compliance. d. In addition, within five (5) days after notification of an exceedance, submit a written report that describes the nature of the exceedance, turbidity results and location, photographs, and any other pertinent information. 4. Water Quality Protection Measures The following Best Management Practices (BMPs) will be utilized to protect water quality in May Creek and the associated wetland during construction. I. Construction Equipment Access a. Construction entrances will be stabilized using quarry spalls and geotextile fabric under the spalls. This will minimize track-out onto the roadway. b. Only low impact rubber tired or tracked construction equipment will be used to access the stream and to transport the sediment. This equipment will move over the reed canary grass and/or pasture grass with minimal disturbance. Equipment will be operated from the stream bank. Construction equipment access points to the stream will be limited in the field to avoid the removal of mature trees. c. Equipment staging areas will be located outside the regulated stream and wetland buffers. Silt fence will be installed around the perimeter of the staging areas to prevent sediment-laden runoff from leaving the area. 4 May Creek Drainage Imprc .nent Project (9Al205) Water Quality. .ection and Monitoring Plan d. Temporary paths used for construction equipment access will be restored to original or better conditions once construction is complete, using an appropriate upland or wetland seed mix. 2. Stream Diversion a. To protect downstream water quality, sediment .and reed canary grass removal shall be done in the dry by bypassing the stream around the construction area. Approximately 100 to 500 feet of stream will be bypassed at a time. The contractor will submit a bypass plan to King County for review and approval at the pre-construction meeting. b. Prior to installing the bypass, a biologist will relocate any aquatic life in the channel to a safe location upstream via hand-netting or other accepted methods of fish removal (following WSDOT Fish Exclusion Protocol and Standards, dated 2006). c. The stream flow will be bypassed by installing a coffer dam on the upstream end of the construction area and using a sump to pump the flow from the coffer dam to a location downstream of the construction. d. Prior to reintroducing the flow to the newly excavated channel, a ·second coffer dam and sump will be installed at the downstream limits of the construction area. To ensure that state water quality standards can be met, flow will be introduced to the newly excavated channel, and turbid water will be pumped out at the downstream end of the construction area, and will be discharged to a vegetated upland area, until the water flowing through the channel meets state water quality standards. At that point, the cofferdam and sump will be removed and the flow will be allowed to continue downstream into the undisturbed channel. e. To promote infiltration, a perforated pipe will be used to disperse the pumped turbid water over a vegetated upland area. If the vegetated upland area receiving discharge becomes saturated, the water will be pumped to a Baker tank, or equivalent, and disposed of offsite. f. If it is not possible for the water flowing through the newly excavated channel to meet water quality standards within a reasonable amount of time, then contingency measures may be implemented to decrease sedimentation and turbidity. These measures may include bringing in streambed gravel for the channel or placing a biodegradable erosion control blanket in the bottom of the channel. 3. Sediment Transport and Drying Areas a. Excavated sediment will be transported from the stream channel in a Crawler Carrier, or similar tracked or rubber tired hauling equipment. During transport, the sediment will be carried in the sealed tub of the 5 May Creek Drainage Jmpro, __ .,ent Project (9Al205) Water Quality l action and Monitoring Plan Crawler Carrier. This sealed tub will contain any sediment-laden water. In the unlikely event, that sediment-laden water does leak out of the tub, the following additional BMPs may be used: 1. Lining the tub with plastic to prevent leakage 11. Using sand bags, or a similar plug, at the back end of the carrier to prevent water from spilling out the back b. Sediment that is not saturated will be spread directly on the disposal sites, shown in the plans and will be stabilized by applying a native seed mix. Silt fence will be installed around the sediment disposal area to further minimize the possibility of sediment reaching the stream or wetland prior to the seed mix reaching 80 percent coverage. c. Sediment that is saturated will be transported to the soil drying area. A sump will be installed in the soil drying area, and excess turbid water will be pumped to a vegetated upland area. To promote infiltration, a perforated pipe will be used to disperse discharged water over the area. If the vegetation area becomes saturated, water will be pumped to a Baker tank or equivalent. 4. Construction of Wetland Alcoves along May Creek a. When excavating adjacent to the stream channel on the west side of 148th Avenue SE, an earth plug shall be left between the existing stream channel and the excavation area. Prior to removing the earth plug and connecting the excavated channel, a turbidity curtain shall be installed to protect the stream from sedimentation and turbidity. b. Before removing the turbidity curtain, suspended sediment in the water behind the turbidity curtain will be allowed time to settle out. 5. Other Best Management Practices a. Clearing limits will be clearly, flagged prior to construction. No disturbance will be allowed outside the clearing limits. b. In-stream sediment and vegetation removal will occur only during the work windows designated in the permit to protect aquatic species. c. The temporary erosion and sediment control facilities will be inspected daily by the CESCL and maintained by the contractor. d. A King County staff member will be onsite at all times during construction activities to monitor in-stream water quality and ensure compliance. 6 Figure 1: May Creek Water Quality Sampling Locations During Construction legend 0 Project Area Limits City Boundaries o River Mites e Water Quality Sampling Locations July 12, 2011 0 125 250 500 750 Feet \ :~.:\ ~~-~;)~ '~i~ ".,<~-_, . ) >:~; .·:-, -_ ~-~--~-,...,·_ .. i . --"{..:· ·,,.,Y."~ t . . .. " ·,·,:;, {,, $9.k: '-' .;, ~!(,:•'.. '~~."";., ,., ··.d'.-" " .~ R ·• -' • \._., , • 11 '''·'" -~";, · -' F·"1's,: ~ . ··~, . .. '-':1iz:':t<1:""i ~ ·q:, ~ \ ij~:;.;c /( .,, -.; ~,;.;, --~ :4.-,:~,~ ... _ . .,.it;7 1~::-_ ~--l,--1 ': 'it, ~ ~-:lit?\~ -·~. " J /l ~'~?;~,.;. ~-_;~. =-~ The information Included on lhis map hes been ~ed by King County staff from e varisty ol sotJ"ces end b subject to change Wlll'lout notice. )Ong Count)' makn no representatlone or Wlltl'3lltles, express or implled, as to accoracy, r::omple1-ss, llmellnes$, or lljhls to the use of sudl lnfom'latlon. This cloc:ument le not Intended for use as • wrvey produ,:;l King County shall not be llablefor_.,, gi,rieral, epeclal, Tidlreet, locitlental, or consequenllel damag85 lnduchliJ, but ~ not !irr.tad lo, losl ~orbit profits resulllng from Ule · use or mlsu:se of lhe lnforn.lon eontalned on lhla map. Any sale al this map or b"lfonnallDn on 1h11 map Is prohlbitad except by written permission of King County. 1 ~~ ~ King County Memo Page 1 To: Rebekah Padgett, 401 Coordinator, SEA-NWRO From: Patricia L. Olson, Senior Hydrogeologist, PhD, LHG, SEA-HQ CC: Patrick McGraner, Erik Stockdale Date: August 15, 2011 Re: Comments on Upper May Creek dredging project My comments are mostly based on observations from our field visit on 07/29/2011 supplemented by technical documents provided by King County. I also reviewed comments from USCOE, Muckleshoot Tribe, and downstream property owners but did not include in my discussions. I have many comments on the King County documents. But I have limited time so this memo contains only a summary of some important issues. 401 certification and WQ issues The King County memo from Julia Turney to Doug Chen dated 2/11/2011 discusses how the project will increase the channels fine sediment transport efficiency within the project area (pp 14 ). The memo also states that fine sediment and organic material will be transported downstream at a constant rate rather than an episodic rate (pp 15) and sediment delivery to May Creek will be reduced "in the project area". This will be a change in the current sediment transport regime and current downstream effects from the fine sediment transport. Since lower flows will be transporting sediment, the fine sediment will likely be deposited in areas upstream of where high, episodic flows would deposit the sediment However, the memo does not address what sediment volumes will be transported and where fine sediment will be deposited ·downstream other than to say it won't be Lake Washington. While the memo says that the project will decrease the agricultural sediment source at some time in the future, it does not say how long the increased sediment load will occur. The memo states that quantitative sediment estimates are not available (pp 16). These factors present ambiguities in terms of water quality effects. Dredging The project seems somewhat short-sighted because one time dredging will not solve the flooding extent and duration over time. LiDAR data indicate that there are large floodplain areas below the channel elevation (Figure 1 ). Some of this is may be due to LiDAR processing for the bare earth DEM. However, the Hand H study supports this conclusion (pp 19). The "flood basin" type Iandform may be a natural condition or it may be due to years of dredging and lowering groundwater levels which promotes subsidence in organic rich soils ( e.g. hydric and peat soils). Wetland drainage leads to oxidation of the upper organic horizon burning up organic component. The weight oflivestock and machinery will increase the compaction and subsidence as well ( e.g. Devin and others 1999). The survey notes that accompany the General Land Office (GLO) maps shown in the Turney memo indicate that the upper basin was mostly a groundwater fed wetland system. These conditions suggest that dredging is somewhat akin to trying to channelize a bathtub where water inflow is greater than outflow. EXHIBIT 24 A • Cost-benefit: There may be a cost-benefit analysis but I haven't found it There should be cost-benefit analysis of various options including removing backwater effects caused by bridges, reducing reed canary grass, reducing or eliminating fine sediment sources, and removing willows and replanting with vegetation that was documented to occur in the area including cottonwood, ash, maple, cedar and undergrowth species such as alder, native Pacific crabapple (Mal us fusca ), and vine maple. Backwater effects Backwater caused by the McFarland footbridge is the primary reason for gravel deposition just upstream of the bridge. The FEMA longitudinal profile indicates that backwater likely occurs at floods less than the 10-year flood. The King County Hydraulic and Hydrologic, Analyses of the May Creek, Channel Restoration Projec~ 12/17/2010 {hereafter referred to as the Hand H study) includes measured water surface profiles that include the footbridge. Table 1, pp 4-5 shows the footbridge location as river mile 4.612. Figure 3, pp 19 shows the water surface elevations measured on 01/08/2009 and 01/22/2009. The measured water surface profiles just upstream of the bridge show the backwater effect However, the documents ignore this effect For example, on pp 31, of the Hand H study, a description of gravel bar and flooding is given: "During mean annual flows (8.6 cfs through the study area), control points are vegetation choking points in the wetland downstream of 148th Ave SE bridge and mildly so upstream of 148th and gravel deposition where Long Marsh enters into May Creek at approximately river mile 4.64, just upstream of a footbridge. This high point of gravels controls the water surface elevation upstream approximately for 2000 feet to a footbridge located approximately at river mile 5.04. Similarly for higher flows ( e.g. 1 year event), Long Marsh again controls water surfaces upstream for the same reach length." Again on pp 54: "These results are also dependant on the relocation of where Long Marsh creek deposits gravels during storm events. This tributary has clearly been shown in the past to deposit enough gravels to effectively backwater May Creek upstream of its confluence. Additionally, shear stresses in May Creek are far below forces necessary to mobilize gravels that are being deposited by Long Marsh creek." Well, shear stresses generally are lower in backwater areas. We visited this site, and the form and location of the gravel bar strongly suggests that the bridge is causing the excess gravel deposition probably due to the back water effect Therefore the bridge is the primary cause of the deposition and backwater effect extending 2000 feet upstream (from H and H study). The gravel would disburse downstream rather than creating an oversized gravel bar if the bridge were sized properly or removed during overbank flows. Instead of evaluating this option, the documents focus on removing the gravel and "mitigating" by removing the existing vegetation buffer along Long Marsh Creek and forcing the Creek into an unnatural planform. The documents acknowledge that the 148th Street Bridge causes a backwater effect This effect can be seen of the FEMA longitudinal flood profiles. While the effect is more local resizing the bridge would also increase hydraulic efficiency just upstream of the bridge. The Long Marsh Creek mitigation project is not mitigation. The proposed stream alignment does not appear to be based on the existing or historic channel characteristics. The LiDAR data shows an alluvial fan but it indicates that there were distributary channels rather than a single channel meandering stream (Figure 1 ). A similar situation occurs on the Indian Meadows alluvial fan. The proposed planform and the area allotted for channel movement is not natural to an alluvial fan o Page 2 ·-· system so is not a restoration project but more of a drainage efficiency project not related to historic fluvial processes and landforms. Geomorphic analysis The geomorphic interpretations and sediment transport study appear to be done by persons not well-versed in fluvial geomorphology and channel response. For example, the Sediment transport study conducted in the ravine (Anchor QEA, LLC, 06/2009) relies on pebble counts along 3 transects for evaluating sediment transport. Pebble counts tend to be biased towards larger sediment This bias means that the median sediment size, for example, could be larger than it really is resulting in higher discharge estimate to mobilize bedload. This may explain why the calculated effective sediment mobilization discharges are between the 5-10-year floods. In boulder areas this makes more sense. However, the sediment I saw in the near the Duffus and downstream properties is much smaller and should be mobilized at a lower discharge. The lower end of the range (73-150 cfs) estimated in the H and H study appears more realistic for the areas we observed. Moreover, for sediment transport, pebble counts should be done primarily on bars not the channel. The sediment transport study appears to have only relied on cross-channel pebble counts. Plus, a statement is made that the channel maybe armored. Channels with pavement or armoring should include a subsurface pebble count ( e.g., Buffington and Montgomery 1997, 1999). As pointed out in the documents, HEC-RAS sediment transport model cannot address variable sediment transport conditions and changing channel elevations (erosion or deposition). Pebble counts may work for reconnaissance level study on the site basis (but not the whole reach), but not for a study related to assessing potential hazards such as damage to structures. Volumetric sediment sampling and more sample locations would be more appropriate in this case King County's Department of Natural Resources, Water and Land Resources Division have well qualified fluvial geomorphologists and geologists. The proponents of this project and the geomorphologists and geologists are in the same division. However, these qualified people appear to not have been consulted for evaluating the sediment transport study, baseline geology and historic channel form and geomorphic processes that created the current conditions, and downstream channel response including migration to changes in flow and sediment regimes. The expertise is available within the same King County department and division. These people should be consulted on this project Downstream bank erosion. Since the sediment transport study and the H and H study appear to rely on reconnaissance site level data that does not include adequate sampling points, l cannot make a determination concerning potential for increased bank erosion downstream of the project area. There are many factors affecting bank erosion in the downstream reach such as riprap focusing flow against unprotected banks, reduction in natural sediment source from bank erosion, and head cutting from response to glacial lowering of the base level and more recent lowering of base level when Lake Washington water levels were lowered for transportation purposes. However, I disagree with the statement made in the Hand H study that the increase in frequency of smaller floods is insignificant While it may be the case, this hypothesis has not been tested using adequate data. This conclusion wouldn't be an issue if there were not structures downstream, but there are. The H and H study indicates that the project will increase the frequency of occurrence for smaller floods (Table 8, pp 47-48). For example, the 1.01 year flood o Page 3 • • (67 cfs) and 1.11 year flood (118 cfs) frequency of occurrence will increase by 16% and 10% respectively. The 2·year event, often considered a surrogate for effective discharge where data are not available, frequency will increase by 5%. The increase in frequency of these small floods could affect sediment transport dynamics. Simply put, the increase in small flood frequency will increase the occurrence of unit stream power (specific weight of water*channel gradient* discharge/active channel width) associated with these small floods by 16, 10 and 5%, unless gradient decreases or width increases. Since gradient is somewhat controlled by valley conditions, stream width is more likely to change. Stream power is an indicator of transport capacity. Increased transport capacity can lead to increased incision and bank erosion. Yet the Hand H study says there will be no significant effect There appears to be a disconnection in the conclusions supporting dredging. A 5-16% increase in stream power for potential sediment transport events is not significant but a 0.04% decrease in flooding duration of 50 cfs is significant enough to dredge (Table 9, pp 53, Hand H study). Since there is disagreement between sediment transport numbers, King County should use its geologic and geomorphic expertise and further evaluate adding sampling points and designing an appropriate sediment transport and erosion study. Also the existing transport modeling should have independent review because not all sediment transport models apply everywhere. In the meantime King County and residents should explore other options such as increasing conveyance capacity un_der 148th Street Bridge and footbridge just downstream of Long Marsh Creek. The foot bridge is obviously an imposition on water conveyance as the sediment wedge developed upstream testifies. The King County documents indicate that flood storage will be reduced in the project area, so additional flood storage to compensate for that loss should be included in the project The GLO survey notes describe upper May Creek from just downstream of the Renton-Issaquah Road and upstream as a crabapple swale. Vegetation consisted of Pacific crabapple, hardhack, willow and some indiscernible tea. There was no mention of any "brook" or other flowing water feature. The vegetation and lack of surface water implies it was a groundwater fed wetland. Restoration of some wetland functions in the project area as well as this area could increase flood storage and attenuate flood volumes downstream. Other options include, reducing reed canary grass, reducing or eliminating fine sediment sources (those above background), and replanting vegetation that was documented to occur in the area including cottonwood, ash, maple, cedar and undergrowth species such as alder, native Pacific crabapple (Mal us fusca ), and vine maple. o Page4 •.. Page 5 References Buffington, J.M., and Montgomery, D.R 1997. A systematic analysis of eight decades of incipient motion studies, with special reference to gravel-bedded rivers. Water Resour. Res. 33: 1993-2029. Buffington, J.M., and Montgomery, D.R. 1999. Effects of sediment supply on surface textures of gravel-bed rivers. Water Resour. Res. 35: 3523-3530 Galloway, Devin, David R. Jones, and S.E. lngebritse, eds. 1999, Land Subsidence in the United States U.S. Geological Survey Circular 1182. ~ Clstribwry_traces -~per_May_all_strelim Up_may_rwse <VALUE> --7.71--7.5 --7.49--7 --6.99--6.5 --6.49--6 --6.99--5.5 .-6.49 --5 --4.99--4.5 ~-4.49--4 D -3.99 --3.5 c=J-3.49--3 CE?J -2.99--2.5 C)-2.49--2 CJ-1.99-·1.5 CJ-1 .49--1 CJ-0.99--0.5 LJ-0.499-0 C]o.001-0.5 CJ 0.501-1 D 1.01-1.5 CJ 1.51-2 D2.01-2.5 LJ2.51-3 D 3.01-3.5 [:]3.51-4 [:]4.01-4.5 [:]4.51-5 [:]5.01-5.5 D 5.51-6 LJ6.01 -6.5 LJ6,51-7 D 1.01-1.5 c:J7.51 -8 D s.01-s.5 c:Ja51-9 [:]9.01-9.5 D 9.51-10 D 10.1-10.5 D 10.s-11 D 11 .1-11.5 D 11 .6-12 D 12.1-12.5 D 12.1S-13 -13.1 -13.5 _ 13.6-14 -14.1-14.5 j{ \. STATE OF WASHINGTON DEPARTMENT OF ECOLOGY Northwest Regional Office• 3190 160th Avenue SE• Bellevue, Washington 98008·5452 • (425) 649·7000 September 1, 2011 Doug Chin, Project Manager King County Water and Land Resources Division 201 South Jackson Street, Suite 600 Seattle, WA 98104-3855 RE: U.S. Army Corps of Engineers (Corps) Reference #NWS-2010-158 Status of Application for Section 401 Water Quality Certification and Coastal Zone Management Consistency for the May Creek Drainage Improvement Project, Renton, King County, Washington Dear Mr. Chin: The U.S . Army Corps of Engineers (Corps) issued a joint public notice with the Department of Ecology (Ecology) for the above project on September 24, 2010. Ecology has one year to issue its individual Section 401 Water Quality Certification (WQC). On August 31, 2010, Ecology notified you by ce1tified letter that this project would require an individual WQC and Coastal Zone Management Consistency (CZM) determination and requested additional information. Throughout the review of this project, Ecology has raised a number of questions about the purpose and need of the project, as well as technical issues regarding the wetlands, sediment tt~po1t, and water quality (see Attachment 1 ). As the statutory deadline of September 23. 2011 approaches, we are concerned that many of these issues have yet to be fully addressed and we will not have reasonable assurance that water quality standards :will be met. In order to complete the WQC process and make our CZM determination; we need the following additional information: • Description of how the sediment disposal areas will be stabilized in order to prevent fine material from entering waters of the state (including wetlands). • Construction Water Quality Protection and Monitoring Plan (King County, July 2011): o Page 1, Section 2: The citation for the section of the water quality standards that allows a temporary area of mixing for turbidity during construction should be corrected from WAC I73-201A-400 (4) and (6) should be corrected to WAC 173- 201A-200(1Xe)(i). · EXHIBIT 24 t, i '--- Doug Chin, Project Manager September 1, 2011 Page 2 of 6 o Page 2, Section 3, Sampling Locations: Ecology agrees that the background and point of compliance sampling locations will need to change as the project moves from segment to segment. And it is understood that Figure 1 is a representative site plan showing sampling locations. Please note that background samples should be taken at the same time as the point of compliance samples . o Page 4, Section 3, Long-tenn Data Storage and Reporting: The plan indicates that data will be provjded to regulatory agencies upon request. The plan should be updated to reflect that if no exceedances are detected results of water quality sampling should be sent to my attention at Ecology on a monthly basis and that any exceedances should be reported within 24 hours with the following information: a. A description of the nature and cause of exceedance. b. The period of non-compliance, including exact dates, duration, and times and/or the anticipated time when the Applicant will return to compliance. c. The steps taken, or to be taken, to reduce, eliminate, and prevent recurrence of the non-compliance. d. In addition, within five (5) days after notification of an exceedance, submit a written report that describes the natw·e of the exceedance, turbidity results and location, photographs, and any other pertinent information. • It is expected that there will be stream water temperature changes between the time the Cowity removes more mature vegetation and when the replanted vegetation reaches the size to shade the creek, creating an additional impact to water quality. What measures will be tak~n to address this? • The May Creek Drainage Improvement Project (9Al205) I(jng Cowity Water and Land Resources Division Stream and Wetland Impact Analysis and Mitigation Plan, prepared by King County Road Services Division, revised July 2011, needs to be revised to: o Vegetative coverage of 80 percent under Section 6.1, o Replanting of dead plants to 100 percent for years 1 and 2 under Section 6.1, and o Include submittal of an As-Built Report and monitoring reports for years 1 and 2 under Section 6.2, Post-Construction Monitoring, • The memorandum from Julia Tumey to Doug Chin, King County, RE: May Creek Drainage Improvement Project: SE May Valley Road 148th A venue SFr-Sedirnent Assessment, dated February 9, 2011, does not address what sediment volumes will be transported and where fine sediment will be deposited downstream other than to say it will not be Lake Washington. While the memorandwn states that the project will decrease the agricultural sediment source at some time in the future, it does not say how long the increased sediment load will occur. The memorandum states that quantitative sediment estimates are not available (page 16). J .\. Doug Chin, Project Manager September I, 2011 Page 3 of6 King County developed a plan to monitor for erosion downstream from the project area (memorandum from Don Althauser, King County, to Bill Kerschk.e and Julia Tumey, King County, RE : May Creek Drainage Improvement Project (9Al205) Post- Construction Erosion Monitoring Phm-Downstream of 148th Avenue SE, dated August 4, 2011). The plan needs to be revised to include the project area . The sediment monitoring plan should monitor sediment accumulation or erosion in the creek and changes in channel cross-sections and longitudinal profile to provide information on project effectiveness. It also should include contingencies in case the project does not perfo1m as · expected. • The revised JARP A #6a, Stream/Wetland Mitigation, first bullet, states that fencing will be installed around the planting areas to minimize livestock access to the stream. This appears to refer to the riparian planting buffer on both sides of May Creek-is this correct? Current site plans show fencing around the mitigation area west of 1481h A venue SE, however the plans are do not show fencing that would permanently exclude livestock from direct access to the resto1·ed riparian planting buffer area and creek upstream of I 481h Avenue SE. The plans should be updated to reflect this . • #6d of the J ARP A refers to a riparian planting buffer along Long Marsh Creek. Will the buffer be on both sides of the creek? How wide will the buffer be? Will there be a buffer along the new side channel, and if so , how wide will this buffer be? Are the riparian buffer areas along Long Marsh Creek and the side channel included in the proposed mitigation calculations-Ecology does not believe that this should be included. • #6d of the JARP A mentions that 16 pieces of large woody debris will be placed in the off-channel alcoves. Does this figure include the snags? And is it correct that another 60 pieces of large woody debris will be placed in the wetland enhancement area per the JARP A? These figures are inconsistent with the Mdy Creek Drainage Improvement Project (9Al 205) King County Water and Land Resources Division Stream and Wetland Impact Analysis and Mitigation Plan, prepared by King Cqunty Road Services Division , revis ed July 2011, page 4, first bullet, which states that 76 pieces oflarge woody debris and 2 snags will be installed . These figures need to be clarified. • In King County's July 22, 2011 response to May 11,201 I comments by Karen Walter, · Muckleshoot Indian Tribe (page 3), the County mentions a Draft Long Marsh Creek Sediment Control and Habitat Restoration Project Basis of Design Report and says that the final report will be available upon request. Please provide a copy of this report to Ecology. • On September 16, 2010, Ecology noted concern about the lS "foot riparian vegetation buffer in comments on the State Environmental Policy Act Mitigated Determination of Non-Significance (MDNS). Specifically, we questioned the effectiveness of this size buffer in shading out reed canary grass and stated that we could not support the proposed Doug Chin, Project Manager September 1, 2011 Page 4 of6 C project with this size buffer. The proposed 15-foot buffers remain below the best available science which would more closely approximate 30-35 feet. As Karen Walter of the Muckleshoot Indian Tribe bas pointed out (May 11, 2011 comment letter to Ecology), King County Code requires existing livestock operations to implement a fann management plan or meet management standards outlined in the Code. In King County's July 22, 2011 response to Ms. Walter, you indicate that two of the four livestock operations have developed plans and that the buffers specified in these plans are 25 feet-IO feet more than the County is proposing. • In Ecology's comments on the MDNS we also noted that the proposed planting of the "buffer" particularly on the left bank in Reach 4 is problematic because this area is NOT buffer. It is wetland that likely receives runoff from upslope seepage as well as bank overtopping. This area is very wet and needs to be planted with native vegetation that can tolerate long periods of inundation. Concerns remain with regards to plant establishment in wetter reaches, specifically on the left bank upstream of Long Marsh Creek. Site plans are not specific as to which plants will be installed in this reach. • It is Ecology's assessment that backwater caused by the McFarland footbridge is the primary reason for gravel deposition just upstream of the bridge, extending 2,000 feet upstream. The form and location of the gravel bar indicates that the bridge is the p.dmary cause for excess gravel deposition probably due to the backwater effect. Therefore, it appears that the bridge, rather than the gravel bar, is the p1imary cause of the deposition and backwater effect extending 2,000 feet upstream. The report focuses on dredging and vegetation removal, without considering resizing or removal of the bridge. Additionally, the documents acknowledge that the 148th Avenue SE Bridge causes a backwater effect. Resizing the 148th Avenue SE bridge would increase hydraulic efficiency just upstream of the bridge. King County and residents should explore other options such as increasing conveyance capacity under the 148th Avenue SE bridge and the footbridge just downstream of Long Marsh Creek. • Ecology believes that the effectiveness of the proposed action for the stated intent of decreasing the duration of surface water on the grazed wetlands: o Has not been fully demonstrated to merit the level of impacts proposed for 0.04% decrease in flooding duration of 50 cubic feet per second ( cfs ), and o One-time dredging will not solve the flooding extent and duration over time because large floodplain areas lie below the channel elevation; water inflow into the wetland system appears to be greater than the outflow; no upstream sediment study has been provided with detailed plans to reduce upstream sediment; changes to the 148th Ave SE bridge and footbridge downstream of Long Marsh Creek have not been proposed to increase conveyance capacity. • King County's Department of Natural Resources, Water and Land Resources Division has well qualified fluvial geomorphologists and geologists on staff; however, it does not J. . .\. Doug Chin, Project Manager September 1, 2011 Page 5 of6 appear that they were consulted for evaluating the sediment transport study, baseline geology and historic channel form and geomo1phic processes that created the current . conditions, the downstream channel response including migration to changes in flow and sediment regimes. The studies upon which the proposal is based appear to be flawed in terms of making conclusions based on insufficient information or incorrect data. . . King County should utilize its geologic and geomo1pbic expertise and further evaluate adding sampling points and designing an appropriate sediment transport and erosion study. Additionally, the existing transpo1t modeling should have independent review because not all sediment transport models apply everywhere. Ecology questions the premise upon which the proposal is based and cannot complete its review until this work is complete and the County has reassessed the project. Unless we receive all of the above documentation by September 16, 2011. Ecology will have to deny the WOC/CZM for this project. Receipt of a denial without prejudice does not preclude you from resubmitting a request for 4~ 1 Certification at a later date . Please contact me if you have any questions regarding this letter or the 401/CZM Certification process at (425) 649-7129 or e-mail at Rebekah.Padgett@ecy .wa.gov . Sincerely, ~{~ Federal Permit Manager Shorelands and Environmental Assistance Program RRP:cja By certified mail #7011 0470 0003 3720 8964 Cc: TJ Stetz, U,S. Army Corps of Engineers Lori Lull, U.S. Army Corps of Engineers E-Cc : Patrick McGraner, Ecology Patricia Olson, Ecology Erik Stockdale, Ecology Loree Randall, Ecology Doug Chin, Project Manager September 1, 2011 Page 6 of6 3/24/10 5/5/10 9/16/10 4/26/11 4/28/11 Attachment 1: May Creek Key Ecology Correspondence Chronology Ecology raised concerns in an e-mail that followed up on a 2/22/10 site visit, including the effectiveness, purpose, and need of the project, as well as the effectiveness of the IS-foot-wide buffers. Ecology patticipated in an interagency pre-application meeting where we provided substantive comments regarding the effectiveness, purpose, and need of the project, as well as the need to redelineate the wetland, buffer width, and livestock access to the creek. Ecology submitted comments on the State Environmental Policy Act mitigated detennination of non-significance regarding effectiveness, purpose, and need of the proposal, buffer width, how wet the left bank is in Reach 4 for establishing canopy cover, the degradation of the pastures and need for farm plans to protect riparian habitat and creeks, and livestock access to the creek. Ecology participated in an interagency site visit where we raised questions about the effectiveness, purpose, and need of the project, permanent protection of the mitigation area, the buffers on Long Marsh Creek, whether the Long Marsh Creek work was really mitigation, monitoring of sediments in the project area and downstream> best management practices, buffer width, how wet the left bank is in Reach 4, the need for future dredging. Ecology followed up by e-mail documenting questions raised at the 4/26/11 site visit. . J . . . .. ~ KingCounty Water and Land Resources Division Department of Natural Resources and Parks Ki ng Street Center 201 South Jackson Street, Suite 600 Seattle, WA 98104·3855 206.296.6519 Fax 206.296.0192 TTY Relav : 711 September 16, 20 I 1 Via Hand Delivery Rebekah Padgett Federal Permit Manager Shorelands and Environmental Assistance Program Washington State Department of Ecology Northwest Regional Office 3190 -160th Avenue SE Bellevue, WA 98008-5452 RE : May Creek Drainage Improvement Project -Additional lnfonnation <Reference No. NWS-2010-158} Dear Ms. Padgett: The King County Water and Land Resources Division (WLRD) has reviewed the comments provided by the Washington State Department of Ecology in your letter dated September 1, 2011 . In response to your comments, I am providing the following additional project information: 1. Description of how the sediment disposal areas will be stabilized in orde r to prevent fine material from entering waters of the state (including wetlands). The sediment disposal areas will be stabilized using the upland area erosion control seed mix specified on Sheet 18 of the July 28, 2011 design plans. To minimize the remobilization of this material prior to seed germination, a silt fence will be installed around the sediment disposal area and will be removed once the grass has reached 80 percent coverage. 2. Construction Water Quality Protection and Monitoring Plan (King County July 2011) ... The requested edits have been made and a revi sed version of the plan is enclosed. EXHIBIT 24 C YqQe=-:, PaMett b'er 16, 2011 Page2 3. It is expected that there will be stream water temperature changes between the time the County removes more mature vegetation and when the replanted vegetation reaches the size to shade the creek, creating an additional impact to water quality. What measures will be taken to address this? The majority of the mature vegetation that is being completely removed from the system is reed canary grass. In areas where willow and other trees have begun to shade the stream, only the vegetation that is growing in the stream will be removed and at select access points as shown on the plans, leaving the high-level canopy. Therefore, the amount of change in near-tenn water temperatures may not be as prominent as expected. Under existing conditions flow rates in the summer, when stream temperatures are typically the highest, are low given they have been measured at 148th Avenue SE to be 0.25 cfs (e.g., 2009). With a low flow rate, water depths generally will be quite shallow when unimpeded . However, the existing vegetation (i.e., mostly reed canary grass) likely causes velocities to drop even more, increasing the backwater influences. Thus, while existing vegetation provides shade to the stream, it also increases travel time through the system, and more exposure with a deeper water column, thus increasing the amount of potential thennal input into the stream in the unshaded areas. The true balance between these effects is site specific and variable depending on local channel conditions, and with a stream aspect East-West and the primary type of vegetation being removed (i.e., reed canary grass), the shade would be mostly effective near the left (south) bank only. Additionally, the current substrate in the stream system is dominated by fines with high organic content. This muck greatly reduces the exchange of surface flows and temperatures with the subsurface (i.e., hyporheic zone) below the channel bed. Fluxes with the hyporheic zone cools stream surface temperatures such that, with optimal substrate (i.e., inorganic gravels instead of organic fines), relative shallow water depths could improve water temperature with mixing of cooler shallow groundwater temperatures (Gooseff, M.N ., S.M . Wondzell, R. Haggerty, and J. Anderson . 2003 , or Harvey, J.W. and B.J. Wagner. 2000). With a successful project, the silty and organic fines will have been removed from the stream channel, leaving gravels more beneficial to allow for this flow rate exchange. Therefore, King County believes that the long-tenn gain associated with planting the riparian buffer for 15 feet on both sides of May Creek, out-weighs the potential short- tenn impacts to water temperature as a result of removing the reed canary grass. 4. The May Creek Drainage Improvement Project {9AJ 205) King County Water and Land Resources Division Stream and Wetland Impact Analysis and Mitigation Plan prepared by King County Road Services Division, revised July 201 J, needs to be revised to ... The requested revisions have been made and a revised version of the plan is enclosed. .. , Rebekah Padgett September 16, 2011 Page3 5. The memorandum from Julia Turney to Doug C/rin, King County. RE: May Creek Drainage Improvement Project: SE May Valley Road 148th Avenue SE-Sediment Assessment dated February 9, 2011 does not address what sediment volumes will be transported and where fine sediment will be deposited downstream ... King County will expand the monitoring area for erosion to include the project area if, during the post-construction downstream erosion monitoring, erosion is detected downstream or King County receives complaints from the public that erosion is occurring on their property. 6. The revised JARP A #6a, Stream/Wetland Mitigation, first bullet, states that fencing will be installed around the planting areas to minimize livestock access to the stream. This appears to refer to the riparian planting buffer on both sides of May Creek -is this correct? Yes. Current site plans show fencing around the mitigation area west of 148th Avenue SE, however, the plans do not show fencing that would permanent(v exclude livestock.from direct access to the restored riparian planting buffer area and creek upstream of I 48th Avenue SE. The plans should be updated to reflect this. The plans have been revised to clarify this intent and are enclosed. 7. #6d of the JARPA refers to riparian planting buffer along Long Marsh Creek Will the buffer be on both sides of the creek? Yes, both sides of the creek will be planted. Please refer to Sheet IO in the Long Marsh Creek Restoration· JARPA drawin~ dated July 20, 2011 for the plan. How wide will the buffer be? The total width of the Long Marsh Creek channel and buffer planting will be 30 feet. The channel is approximately 8 feet wide, which leaves 11 feet from top of bank to the existing pasture for buffer planting on each side of the channel. This is shown on Sheet 5 of the Long Marsh Creek Restoration JARPA drawings. Will there be a buffer along the new side channel, and if so, how wide will this buffer be? Yes. Please refer to Sheet 10 in the Long Marsh Creek Restoration JARPA drawings for the planting plan along the side channel. There will be approximately 6 to 8 feet of plantings on the north side of the side channel. Rebekah Padgett September 16, 2011 Page4 Are tlie riparian buffer areas along Long Marsh Creek and the side channel included in the proposed mitigation calculations -Ecology does not believe that this should be included. As requested by the Corps and Ecology, the riparian buffer areas along Long Marsh Creek and the side channel were not counted as mitigation. The Long Marsh Creek project is considered an impact as shown in Tables 2 and 3 of the Impact Analysis and Mitigation Plan (King County, July 2011). 8. #6d of the JARP A mentions that 16 pieces of large woody debris will be placed in the off-channel alcoves. Does this figure include the snags? No, the snags are in addition to the large woody debris. There will be 16 pieces of large woody debris and two snags placed in the off-channel alcoves. And is it correct that anotlier 60 pieces of large woody debris will be placed in the wetland enhancement area per the JARPA? Yes. These.figures are inconsistent with the May Creek Drainage Improvement Project (9Al 205) King County Water and land Resources Division Stream and Wetland Impact Analysis and Mitigation Plan prepared by King County Road Services Division revised July 2011, page 4,firsl bullet. whicli states that 76 pieces of large woody debris and 2 snags will be installed. These .figures need to be clar(fied. The Impact Analysis and Mitigation Plan and #6d in the J ARP A are both correct. A total of76 pieces oflarge woody debris will be placed in the wetland enhancement mitigation area (16 pieces will be specifically placed in off-channel alcoves and another 60 pieces throughout the wetland planting area). In addition, two snags will be installed in the off-channel alcoves. 9. In King County ·s July 22, 2011 response to May 11, 2011 comments by Karen Walter, Muckleshoot lndian Tribe (page 3). the County mentions a Draft Long Marsh Creek Sediment Control and Habitat Restoration Project Basis of Design Report and says that the final report will be available upon request. Please provide a copy of this response to Ecology. The report is enclosed. r .. Rebekah Padgett September 16, 2011 Page 5 JO. On September 16, 2010. Ecology noted concern about the 15-foot riparian vegetation buffer in comments on the Stale Environmental Policy Act Mitigated Determination of Non-Significance ... The project used as an analog the planted buffer area on the upstream end of the Colasurdo property as a basis for what is being proposed now. This planting area is approximately 12 feet wide and is functioning as a good buffer with no evidence of reed canary grass in the buffer area. In addition, much of the project site has no buffer now and the 15-foot buffer proposed is a substantial improvement from this condition. 11 . In Ecology's comments on the MDNS, we also noted that the proposed buffer planting of the "buffer" particularly on the left bank in Reach 4 is problematic because this area is NOT buffer ... Revised design plans have been enclosed, which show a more specific planting plan for the wet versus dry riparian "buffer'' areas. 12. It is Ecology's assessment that the backwater caused by the McFarland footbridge is the primary reason.for gravel deposition just upstream o.fthe bridge, extending 2,000 feet upstream ... The footbridge possibly does have some effect on the competency of mainstem May Creek to move gravels deposited by Long Marsh Creek due to backwater conditions under a range of conditions (e.g., 2-to 10-year flood frequencies}. The larger the event, the less May Creek can move gravels because of downstream conditions and more water if conveyed overbank rather than in-channel. However, because Long Marsh Creek is a much steeper gradient system, it is likely the size of gravels deposited for the same "size" storm are significantly larger than what May Creek can pass at an equivalent storm. For any given "same" storm that may deposit gravels from Long Marsh Creek, May Creek will be less effective to move those gravels downstream during the same storm event. For example. assuming average gravel size (i.e., Dso) is equal to 20 mm, the critical shear stress for the system (the point at which velocities can move the average gravel size) might approximate to 0.35 psf (pounds per square foot). Existing conditions is estimated to be between 0.25 and 0 .33 psf (suggesting the system is in equilibrium with that assumption for those size events-2-year through I 0-year}. By removing the footbridge and removing the gravel bar, shear stresses might increase by a small amount, which might be slightly above the estimated incipient motion and capable to move the average gravel size. However, the magnitude of flow rates to generate these stresses is fairly large infrequent events (i.e., 2-to 10-year). Thus, the time in between these events potentially could revert back to existing backwater conditions with deposition of fines and organic detritus from upstream leading back to choking vegetation. Rebekah Padgett September 16, 20 11 Page6 13. Ecology believes that the effectiveness of the proposed action for the stated inlenl of decreasing the duration of surface waler on the grazed wetlands ... This is correct that the difference of durations at the same flow rate is 0.04 percent and inconsequential in any improvements or impacts. The significant improvement is the reduction of overbank flooding that occurs between 6 cfs and SO cfs . For existing conditions, the pasture lands flood starting around 6 cfs . Under the proposed conditions, overbanlc flooding will begin to occur at SO cfs (slightly less than a 1-year event). Thus, it is assumed that flooding will occur every year after the proposed project, but less frequently during seasons with smaJler storm events . It was acknowledged in the Hydrologic and Hydraulic report that the assumed reductions in durations will be less than stated because of the return pathways to the stream and that was not the intent of the project to change receding waters . It was only to reduce the frequency of smaller events (as previously described above). 14. King County's Department of Natural Resources and Parks , Waler and Land Resources Division, has well qualified fluvial geomorpho/ogists and geologists on staff; however, it does not appear that they were consulted ... King County WLRD feels that the existing studies are adequate for assessing project impacts, and it is not possible to coordinate an independent review for the existing sediment transport models by the September 16, 2011 deadline . If Ecology would like the County to set up an independent review for these studies, the County requests clarification from Ecology on the type of review that would be acceptable. In support of this letter, I am enclosing the following updated information : I . Updated Design Plans and J ARP A drawings showing : a. Fencing on both sides of May Creek that excludes livestock access b. Revised planting plan for the wetter buffer areas c. Erosion control and sedimentation plan for sediment disposal areas 2. Long Marsh Creek Basis of Design Report (2 copies) 3. Revised Impact Analysis and Mitigation Plan (2 copies) 4. Revised Construe/ion Water Quality Proleclion and Monitoring Plan (2 copies) .. ' ·,. Rebekah Padgett September 16, 2011 Page? If you have any additional questions, please contact me at doug.chin@kingcounty.gov or 206-296-8315 . Doug Chin, P Project Manager Capital Services Unit DC:bgoas Enclosures • cc: Don Althauser, Managing Engineer, Capital Services Unit, Water and Land Resources Division, Department of Natural Resources and Parks Lindsey Miller, Environmental Engineer, Environmental Unit, Road Services Division, Department of Transportation . .. ti KingCounty Water and Land Resources Division Department of Natural Resources and Parks Ki ng Street Center 201 South Jackson Street, Su i te 600 Seattle, WA 98104·3855 206.296.6519 Fax 206.296.0192 TTY Re lay : 711 February 9, 2012 Rebekah Padgett Federal Pennit Manager Shorelands and Environmental Assistance Program Washington State Department of Ecology Northwest Regional Office 3190-160th Avenue SE Bellewe, WA 98008-5452 RE : May Creek Drainage Improvement Project (Reference #NWS-2010-158) RCSJ>onse to Dr. Patricia Olson's August 15, 2011 Memo Dear Ms. Padgett : The King County Water and Land Resources Division (WLRD) is providing the following additional information in response to the project issues raised in the memorandum written on August 15, 2011 by Dr. Patricia L. Olson, Senior Hydrologist, Washington Department of Ecology (Ecology) and in response to the meetings between King County WLRD and Ecology on October 18 and November 14 and 15, 2011. Benefit of the Project Dr. Olson questioned the benefit of the project based on her conclusion that a 0.04 percent decrease in flood duration at 50 cubic feet per second (cfs) is not significant enough to dredge; however, what was overlooked was the point that the project is not trying to decrease flood durations at 50 cfs. The project will decrease flood durations below 50 cfs (Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project, Jeff Burkey, December 2010). King County WLRD agrees that an improvement of only 0.04 percent would not warrant a project; however, the benefit of the project is actually approximately 21 percent reduction in flooding of adjacent fields below 50 cfs . Under current conditions, the stream overflows its banks starting at 6 cfs, while post-project, the stream will remain in its banks for flows up to 50 cfs (slightly less than a I-year event). This means that for flows between 6 cfs and 50 cfs , flooding will no longer occur post-project. This is an improvement that King County WLRD does feel is significant. For flows over 50 cfs, Dr. Olson is correct in noting that there will not be much of a change in the amount of flooding . EXHIBIT 24 P ·-·-@ Rebekah Padgett February 9, 2012 Page2 Cost-Benefit Analysis Dr. Olson questioned whether a cost-benefit analysis had been done for various options considered for the project. The King County Comprehensive Plan calls for the protection of both agricultural uses and equestrian activities, both of which are at risk due to the flooding in the May Valley. As part of the King County Agricultural Program, the County is working to preserve prime agricultural soils, protect water resomces, and ensure the continuing economic vitality of agriculture in the County. King County has historically been a productive agricultural region with dairies, livestock operations, crop farms, and berry fields. Drainage problems are one of the problems that have significantly contributed to the reduction of farmland in King County. Although most costs can be reasonably estimated for undertaking various alternatives, the benefits of preserving the rural character of a community cannot be easily measured and monetized. The benefits are collective and public in nature. In addition, the May Creek Basin Action Plan published by King County in 2001 recommended this project as one of the actions needed to correct adverse conditions in the basin. The focus of basin plans has been on reducing flood damages, protecting stream and wetland habitats, and improving the quality of smface and groundwater. This basin plan was developed in coordination with King County, City of Renton, City of Newcastle, and the May Creek Citizens Advisory Committee, which included Andrew Duffus. The basin plan is available on King County's website. Therefore, no additional cost-benefit analysis was conducted for this project above and beyond what was presented in the basin plan. While a detailed cost-benefit analysis was not conducted for the reasons explained above, the project did evaluate a number of alternatives. The alternatives or options ranged from floodplain restoration to upland stormwater controls. The preferred alternative is the current proposal. This alternative proved to be the most practicable for multiple reasons . First, it allows property owners to reclaim more useable pasture at certain times of the year, without requiring them to move their operations to another location . Second, the sediment and vegetation removal does not require land acquisition, and therefore the proposal fits within the King County budget. Third, the proposal does not require permanent fill in the wetland, stream, or floodplain ( except streambed gravels for mitigation). In addition, the mitigation associated with this proposal will protect the stream by restoring native riparian/wetland vegetation and installing fences along the stream , which will prevent livestock access . Sediment Transport to Lake Washington We would like to correct Dr. Olson's interpretation of the February 11, 2011 memorandum from Julia Tumey to Doug Chin . Dr. Olson incorrectly concluded from that memo that fine sediment from May Valley would not be deposited in Lake Washington. This conclusion was incorrect. The memo said that while muck and fine sediment from the May Valley does move downstream to Lake Washington, the May Valley is not the primary source of sediment to Lake Washington . The primary source of sediment entering Lake Washington from May Creek is from the canyon and eroding channels of tributaries downstream of the May Valley (May Creek Current and Future Conditions Report, 1995). The proposed project includes a number of features that will likely decrease the amount of sediment leaving the May Valley, including: Rebekah Padgett February 9, 2012 Page3 • Removing and controlling of reed canary grass (Phalaris arundinacea); • Planting a buffer of native vegetation along the stream bank; • Reducing overbank flooding for flows between 6 and 50 cfs; • Excavating alcoves adjacent to the channel downstream of 148th Avenue SE; and • Designing the Long Marsh Creek restoration to include flood benches that will capture and store sediment prior to it reaching May Creek. Backwater Effects (Long Marsh Creek Footbridge) Dr. Olson indicated in her August 15, 2011 memorandum that the backwater caused by the McFarland footbridge is the primary reason for gravel deposition just upstream of the bridge ... therefore the bridge is the primary cause of the deposition and backwater effect extending 2,000 feet upstream. King County WLRD would like to clarify that this conclusion reached by Ecology is incorrect for flows below the 5-year event. The footbridge is not the predominate cause of backwater effect for the flood events addressed by this project (i.e., flows well below the 5-year event). In summary, sediment deposition from Long Marsh Creek produces higher elevations in the May Creek channel and the backwater effect forces water out of the May Creek channel upstream of the footbridge. This action starts a cycle of reduced sheer stress in the May Creek channel, causing further deposition by Long Marsh Creek and greater overbank flooding by May Creek. Field obsetvations and modeling show that the footbridge does not impede flows below the 5-year event. Modeling results and field obsetvations to support this conclusion are provided in the enclosed Technical Memorandum from Julia Turney and Jeff Burkey dated December 14, 2011 May Creek Drainage Improvement Project-Response to Ecology's September J, 2011 comment on the backwater effect caused by the McFarland (i.e., Gambini) footbridge. Long Marsh Creek as Mitigation Dr. Olson indicated that the Long Marsh Creek portion of the project should not be considered mitigation for stream habitat impact. King County WLRD already received this comment from Ecology staff earlier in the year and addressed the comment in July 2011 by submitting a revised Stream and Wetland Impact Analysis and Mitigation Plan to Ecology. The revised plan removed Long Marsh Creek as mitigation and instead increased the size of the wetland mitigation downstream of 148th A venue SE. The Stream and Wetland Impact Analysis and Mitigation Plan was further revised to address additional comments provided by Ecology on September 1, 2011 and was resubmitted on September 16, 2011. While the Long Marsh Creek portion of the project is not habitat mitigation, it is intended to increase the longevity of the overall project by trapping and storing sediment before it reaches the mainstem of May Creek . Calculations performed for the Long Marsh Creek Restoration Project Basis of Design Report found that the sediment storage capacity in Long Marsh Creek after the project is approximately 74 years. This will help minimize future gravel deposition near the Long Marsh Creek footbridge discussed in the previous section. The Long Marsh Rebekah Padgett Febrµary 9, 2012 Page4 Creek Restoration Project Basis of Design Report was provided to Ecology on September 16, 2011. Post-Project Flow Duration and Freguency During the October 18, 2011 meeting, Ecology requested additional information on the flow durations and frequencies post-project for varying sized flow events. King County WLRD has analyzed flow events at 50, 100, 150, and 200 cfs and the results are provided in the enclosed memorandum from Jeff Burkey to Doug Chin dated January 11, 2011, Comparison of Post- Project Changes in Flow Durations and Frequencies at for Various Storm Events . Methods for Assessing Sediment Transport and Downstream Bank Erosion Several comments were made with respect to the general study approach, methods, and preliminary findings . The study plan was developed to evaluate the threshold of motion through the study area, focusing on the segment below an identified bedrock control point in the channel downstream of 148th A venue SE . The intent was to determine the threshold of bed movement or channel migration under natural conditions. Therefore, monitoring sites were chosen to preclude areas known to be affected by existing human infrastructure. While the HEC-RAS program was used for this analysis, it was generally assumed by the Dr . Olson memo that the sediment transport routines within the model were used to produce the findings in the assessment. This assumption was incorrect. King County WLRD agrees with the concern that HEC-RAS sediment transport methods may not be suitable for this evaluation and therefore chose not to use them for this evaluation. King County WLRD used output from the model for shear stress and calculated sediment transport using a number of methods that are well described in the report. Concern was also raised about the approach of using pebble counts to characterize sediment transport through the reaches and that this method typically results in a larger 050 than reality. King County WLRD does not dispute this comment, but would like to clarify that our findings were not solely based upon pebble count data. Findings were based on data collected after storm events where monitoring elements were evaluated and a determination of bedload movement or bank erosion was made. Dr. Olson's comment that the likely range for initiation of sediment transport at the location visited by her team may be near the lower end of the range we provided (73 to 230 cfs) is not disputed . King County WLRD chose not to select this location for evaluation because it is not representative of reach scale conditions . A more likely driver for risk of failure to the private infrastructure involved at this location is related to ongoing geomorphic processes ( ongoing headcutting) rather than purely sediment transport (initiation of motion). In addition, our study was not designed to and did not conduct a detailed analysis of risk to any specific private infrastructure elements. .. .... . ... Rebekah Padgett February 9, 2012 Page5 In response to the comment "There are many factors affecting bank erosion in the downstream reach such as riprap focusing flow against unprotected banks, reduction in natural sediment source from bank erosion, and head cutting from response to glacial lowering of the base level .... 0 , King County WLRD agrees and tried to select monitoring locations that were not likely influenced greatly by these other stressors . In summary, the study design was not intended to evaluate the site-specific issues and concerns of the individual landowners at the specific location visited by Dr. Olson and her team. King County WLRD believes the risk at that particular location is more closely related to ongoing geomorphic processes (headcutting) than bedload movement or bank erosion. The stream channel just upstream of the Coates' wall is steep and heavily armored with boulders much larger than found in much of the stream bed through the reach. Therefore, stream bed movement through this reach would not occur in the same manner as other stream segments, if at all. If a detailed analysis of this location was conducted, the shear stress necessary to induce bed movement through the area that would affect the Coates' wall, would be greater than that necessary to induce erosion through the initial study area or the additional monitoring locations just downstream of the wall. Therefore, we are not convinced that this effort would provide additional information . However, King County is evaluating existing data to determine if there is sufficient information to conduct a more site-specific analysis . In addition, King County is requesting permission to access site-specific properties to gather information to conduct a more site-specific analysis. If King County is able to conduct a more site specific analysis, then the new information will be provided to Ecology. Ongoing Monitoring and Public Outreach Efforts King County WLRD has been monitoring erosion on the properties downstream of May Valley for the past two years and is continuing to do so presently. Anchor Engineering was retained by King County WLRD to develop the May Creek Canyon Reach Draft Monitoring Plan (provided to Ecology on August 9, 2011 in Post-Construction Erosion Monitoring Plan) for the reach downstream of 148th Avenue SE. This plan was provided to Ecology on August 9, 2011 as part of the May Creek Drainage Improvement Project (9Al205) Post-Construction Erosion Monitoring Plan -Downstream of 148th Avenue SE. In 2010 and 2011, King County WLRD then implemented the May Creek Canyon Reach Draft Monitoring Plan to collect baseline data. The intent of the May Creek Canyon Reach Draft Monitoring Plan is to gather supplemental data to be used to identify and document potential impacts from the upstream project implementation, building upon information gained from the Sediment Transport Study. King County WLRD's ongoing monitoring effort, in the May Creek Canyon Reach (both pre- and post-project), is documented in May Creek Drainage Improvement Project (9Al 205) Post- Construction Erosion Monitoring Plan -Downstream of 148th Avenue SE. Additional monitoring data has been collected on the properties downstream of 148th A venue SE since the August 15, 2011 Post-Construction Erosion Monitoring Plan was written. Most recently, King County WLRD requested access to the Duffus property on November 17, 2011 to do additional survey work and to observe the status of the bank pins installed on his property. The bank pins are used to assess the ongoing erosion. Property access was requested Rebekah Padgett February 9, 2012 Page6 via email and followed up with two phone calls the following Monday, November 21, 2011; however, Mr. Duffus never responded to King County WLRD 's request , so as of the date of this letter, King County WLRD has been unable to access the property to further assess the erosion-related concerns. When the bank pins were originally installed, Mr. Duffus offered to observe the pins during rain events and send reports to King County WLRD staff. Mr . Duffus has not sent any reports since April 2011. Since he also did not respond to King County WLRD 's recent requests to access the property and observe the pins first-hand, King County WLRD staff is currently working under the assumption that there has not been additional erosion on the property since April 2011, despite the large rain event the week of Thanksgiving 2011. Please note , the flows during November 21-25, 2011 peaked at 335 cfs, an estimated 5- to 10-year event, above the 233 cfs flows when channel sediment mobilizes in the ravine . The monitoring data collected in the ravine in the past year is documented in the enclosed report, May Creek Phase 4 Monitoring . Please note that this report is a working document that is continuously updated as new monitoring data is collected. Finally, under existing conditions, King County WLRD has already observed erosion near the private structures of concern downstream . King County WLRD has committed to provide technical advice to the City and property owners on environmentally acceptable methods that could be applied for stabilization and maintenance, such as bioengineered banks and bridge approaches. Currently, these private facilities appear to receive sporadic maintenance and King County WLRD has no information about their structural integrity. Erosion and localized scour is to be expected when flows encounter hard points or structures within the channel, such as is the case with these structures of concern downstream . Each of these structures is within the stream and susceptible to the existing stream flow and scour conditions . King County WLRD staff have observed various materials such as concrete, boulders and rebar, placed at or near the structures to stabilize the stream bed. These structures are already wlnerable to current levels of erosion and natural changes in hydrology. The maintenance of structures to prevent further deterioration is the responsibility of the owner. King County WLRD can provide advice, but cannot offer to provide the improvements to these private structures . Agricultural Best Management Practices ffiMPs} King County is discussing agricultural BMPs with the King County Conservation District (KCD) and is continuing to work with KCD on identifying practical options that will improve water quality. If King County agrees to a practical option with the Conservation District that will improve water quality, King County will provide Ecology this information. To implement any water quality improvements to fann practices, however, requires voluntary participation by individual property owners to add improvements to their farm management practices. King County continues to work with property owners and encourages them to obtain and implement farm management plans, but has no legal authority to require or enforce implementation of farm management plans. In summary, the proposed project will support and protect the agricultural practices in May Valley by reducing overbank flooding during small stonn events between 6 and 50 cfs . The ... . . Rebekah Padgett February 9,2012 Page? longevity of the project will be increased by providing in-channel storage capacity for the sediment and gravels from Long Marsh Creek. King County WLRD is confident that that the existing technical studies support the conclusion that no significant adverse impact will occur downstream; however, since Ecology is requesting additional supporting documentation, King County WLRD will continue to monitor erosion and sedimentation processes to enhance our understanding of the stream channel stability (assuming property owner pennission is granted). King County WLRD is committed to providing technical advice and expertise to property owners so that they can responsibly maintain their own private structures, but King County WLRD cannot offer to maintain or improve privately owned structures. If you have any questions, please contact me at 206-296-8315 . Sincerely, Q~~ Doug Chin, PMP Project Manager Capital Services Unit DC:bgo12 Enclosures cc: Patricia Olson, Senior Hydrologist, Washington State Department of Ecology (Ecology) Eric Stockdale, Environmental Specialist, Ecology Patrick McGraner, Environmental Specialist, Ecology Curt Crawford, Manager, Stonnwater Services Section, Water and Land Resources Division (WLRD), Department of Natural Resources and Parks (DNRP) Don Althauser, Managing Engineer, Capital Services Unit, WLRD, DNRP Lindsey Miller, Environmental Engineer, Environmental Unit, Road Services Division, Department of Transportation f \ ti KingCounty Water and Land Resources Division Department of Natural Resources and Parks King Street Center 201 South Jackson Street, Suite 600 Seattle, WA 98104-3855 206-296-6519 Fax 206-296-0192 TIY Relay: 711 January 11, 2012 TO: Doug Chin, Acting Supervising Engineer, Water and Land Resources Division ·FM: Jeff Burkey, Hydrologist, King County Water and Land Resources Division RE: May Creek Drainage Improvement Project -Comparison of Post-Project Changes in Flow Durations and Frequencies for Various Storm Events In response to comments received from the Washington State Department of Ecology on the May Creek Drainage Improvement Project I have further analyzed the changes in flow durations and frequency in the May Creek post-project for storm events at 50, 100, 150, and 200 cubic feet per second (cfs). The post project hydraulic scenario (Scenario 8) was the staff recommended scenario and what was used for evaluations supporting this memo . For further detail on descriptions of Scenario 8 can be found in the Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project (King County 2010). Table 1 summarizes the average change in annual flow durations post-project for storm events at 50, 100, 150, and 200 cfs. Figure 1 illustrates the same data using a box plot. As is evident in the table, the average change in annual flow durations is near maximum at 100 cfs with 8 hours more per year out of a total of 8760 hours per year, or 0.09 percent increase. Above 100 cfs, the increase in durations diminishes as flow rates increase in magnitude. For very large storm events with flows above 400 cfs (not shown in the table), proposed project conditions actually reduce peak flow durations approximately by one to two percent over existing conditions. T bl 1 A Ch . Fl D f dF p t p . t a e . veraee anges m ow ura 100 an requency os -ro.1 ec . Threshold Metric 50 cfs 100 cfs 150 cfs 200 cfs Average Total Duration Change (hours) per year1 4 8 3 1 Average Duration per Storm (hours) per year -5 -4 0 -1 Average Change in number of storm events per year 3 2 0 0 l There are 8760 hours per year EXHIBI T 2 4 E ( Doug Chin January 11, 2012 Page2 'F g ,E. Figure 1 SummlfY or Annual l ow .... n1 du rations ont 1nn9 May Crntc RIMllt !DI -----------------------------------.-- •• .. • • I I I ... -.,-............. . I I &1)1----+------1--------------------------I I ............ f ...... .. ... .. . . .. .... : ............................................................................................................... . I I aJI----L,------+---------------------------i I I .. ,. . . . ., g Dl-4---~--1---4-------------------------i I .................. !---~ .............................................................................................................. .. ID~------------~~~~~~~---------.--- I ..... , I -r ... ,. ..... I 100 1----4------:------.-~L.........---,=========t-------=-t==~-----,----~ I I I Propo ttd 50 cft Ex1s11ng 100 cft Propoted 100 cft Sctnano Ex1111n9 150 cfs Proposed 150 et'9 When looking at the individual events that make up the averages in Table 1, you see both increases and decreases in flow duration and frequency . These individual numbers are shown in Figures 2, 3, and 4 . Figure 2 characterizes the changes in frequency of events per water year relative to existing conditions , with all numbers zero or positive. Thus, the number of events range from Oto 8 more events per year compared to existing conditions . The histogram categorizes those events into the number of years experiencing the range of increases of events above 50 cfs. For example, there were 8 years (8 on the y-axis) with no changes (0 on the x-axis) in frequency of flow events. There were 8 years (8 on the y-axis) with an increase of 1 event per year (1 on the x-axis). Jumping to the other end of that graph, there were was one year (1 on the y-axis) with an increase of 7 more events over existing (7 on the x-axis). Figure 3 characterizes the frequency in changes of total duration per year. Grouping changes in durations of excursions into groups of 5, there were 11 years wi th between 0 and 5 hours of increase to durations from existing conditions . Moving a couple of bars to the right, there were 4 years with increases of total durations between 15 and 20 hours per year. Then moving to the left we see decreases in total duration ; there are 9 years with decreases of 5 to 10 hours in total duration, and one year with a decrease in durations between 25 to 30 hours . Finally, Figure 4 characterizes the changes in total durations by water year. The blue dots represent the total changes in duration from existing conditions above 50 cfs per year. Referring to the blue dots, there are 35 years with increases and 20 years with decreases in duration s . ' t ( Doug Chin January 11, 2012 Page 3 Figure 2 Histogram for Difference in Number of Excursions above 50 cfs per Water Year (Positive means more storms) 14 12 - 10 C: 8 ::, 8 6 4 2 ---i 0 0 2 3 4 5 6 7 8 Number of Excurions above 50 cfs per water year Figure 3 Historgram of Difference in Duration of Excursions above 50 cfs per year (Negative means shorter durations for Proposed , Positive means longer durations for Proposed) 12 10 8 C: ::, 6 8 4 2 0 -30 -20 -10 0 10 20 30 Duration of Excurions above 50 cfs per year Doug Chin January 11, 2012 Page4 Figure4 Difference in Durations and Frequency of storm events above 50 cfs 40 30 20 10 -10 -20 -30 1950 1960 1970 1980 1990 2010 ,--9------41.,_Yaf-------'---+---J...--e-... ,-Jt.,_----1-----+o 2000 8 ........ Total Durations (hours) ........ Average Duration per event (hours) -40 ...._-~---.-------.-----.---------~--- 1950 1960 1970 1980 1990 2000 2010 Water Year Average Total Duration per year. +3.8 hours (an Increase) Average Duration per Storm Event per year= -4.7 hours (a decrease) Average Change in Number of Storm Events per year • +2 . 7 (an increase) . . DougCrun January 11 , 2012 Page5 Conclusions While overall there is a net increase in durations of flow events above 50 cfs (estimated to be 4 hours more duration above 50 cfs), the years with larger durations are broken up into smaller events reducing the average duration per event with a net reduction of 5 hours per event per year . This average duration per event per year could be considered as an improvement post-project given there are increases in time between larger flow events allowing the stream system time to readjust The key is really to look at the total duration of flow events per year. Post-project there are 28 years with increases of durations ranging from 5 to 30 hours; however, there are also 12 years with decreases in durations ranging from 5 to 30 hours. ® tcn County Road Services Division Department of Transportat ion KSC·TR-0231 201 South Jackson Street Seattle, WA 98104·3856 December 14, 20 I I TO : FM : Doug Chin, Acting Supervising Engineer, Water and Land Resources Division Jeff Burkey, Hydrologist , King County Water and Land Resources Divisio"#~/J Julia Turney , L.G., Environmental Engineer, King County Road Services Division RE: May Creek Drainage Improvement Project -Response to Ecology's September 1, 2011 comment on the backwater effect caused by the McFarland (i .e., Gambini) footbridge In Ecology's September I , 201 I letter to you on the May Creek Drainage Improvement Project, they commented that the backwater caused by the McFarland footbridge is the primary reason for gravel deposition just upstream of the bridge, extending 2,000 feet upstream. The form and location of the gravel bar indicates that the bridge is the primary cause for excess gravel deposition probably due the backwater effect. Therefore it appears that the bridge rather than the gravel bar, is the primary cause of the deposition and backwater effect extending 2,000 feet upstream. King County Water and Land Resources Division (WLRD) maintains that this assessment by Ecology is incorrect for flows below the 5-year event. The footbridge is not the predominate cause of backwater effect for the flood events addressed by this project (i.e. flows well below the 5-year event). In summary, sediment deposition from Long Marsh Creek produces higher elevations in the May Creek Channel and the backwater effect forces water out of the May Creek channel upstream of the footbridge . This action starts a cycJe of reduced sheer stress in the May Creek channel, causing further deposition by Long Marsh Creek and greater overbank flooding by May Creek. Field observations and modeling show that the footbridge does not impede flows below the 5-year event Modeling results and field observations to support this conclusion are provided below . Flow Modeling King County WLRD completed hydraulic modeling comparing the effect of the foot bridge on the ability of May Creek to move sediment (shear stress) near the Long Marsh Creek confluence in May Creek between the existing conditions and post-project conditions. Modeling shows no change to how May Creek moves sediment until approximately between the 5-and IO-year event (post project). Assuming a diameter of 22 mm , the size of sediment measured in Long Marsh Creek where half of the sediment EXHIBIT 24 .f: Doug Chin December 14, 2011 Page 2 was larger and half smaller (D50= 22 mm), incipient motion is estimated to be 0.38 psf, which is about a 5-yr flow event. At 20mm, the approximate size of sediment measured in May Creek at the confluence, incipient motion is about 0.35 psf. This indicates the bridge causes a backwater affect and alters sediment deposition infrequently (approximately between the 5-and 10-year post project and between the 2-and 5-year existing conditions) based on incipient motion computed using Shields eq uation. Table l and Figure 1 compare the modeled flow and shear stresses on the May Creek c hannel between the existing conditions and proposed project conditions. Note that there is no proposal to remove the foot-bridge; the removal in Table I and Figure 1 is shown for comparison purposes only. Table 1: Sheer Stress in May Creek Channel for Modeled Flows (yellow highlighted cells are at or above estimated incipient motion) Shear stress in channel (psO Existin2 Conditions Post-Project Reoccurrence With Without With Without Interval Q (flow) Brid2e Brid2e Brid2e Brid2e 8.6 0.07 0.07 0.03 0.03 13 0.08 0.08 0.04 0.04 29 0.1 0.1 0.08 0.08 50 0.12 0.12 0.1 O. l 64 0.15 0.15 0.14 0.14 109 0.24 0.24 0.2 0.2 148 0.28 0.3 0.26 0.26 165 0.3 0.33 0.28 0.28 2-yr 188 0.32 0.36 0.29 0.29 5-yr 285 0.28 0.49 0.38 0.38 10-yr (approx) 339 0.23 0.51 0.4 0.42 354 0.23 0.5 0.41 0.43 424 0.19 0.43 0.43 0.5 468 0.21 0.41 0.4 0.52 562 0.25 0.36 0.37 0.5 ,,-.. Doug Chin December 14, 2011 Page 3 0 .6 0.5 l0.4 ~ -Exist wBridge QI ::; 0 .3 11'1 -Exist wo Bridge ... tel ~ 0 .2 -Post wBridge 11'1 -Post woBridge 0.1 0 0 200 400 600 Flow Rate (cfs) Figure 1: Estimated shear stress at the confluence of Long Marsh and May Creek Field Observations Field observations of Long Marsh Creek and May Creek were made during August of 2010 and the flood event of December 11 -13, 2010. The flood event of December 2010 i s estimated to be between a 5 and 10-year flow event (see Figure 2). May Creek December 2010 Event (37G -148th Ave) 600 ~-----------------------------------------100-yr soo -,..--------------------------------~--------SO.yr 127 ho<lrs > SOcfs L _______ --------· 400 '--------~--------------20-yr i ~-------~------------(-------,~~:.1------10-yr 1 300 -- « ~-----------------l --5-yr 200r---------------- 100 ---1.0 1-yr 0 +- 12/8/2010 0:00 12/10/2010 0:00 U/12/20 100:00 12/1 4/20100:00 12/16/20100 00 11ml (houri'/) -Disc hargo(clsJ --nowrrec, -so cfs Figure 2: Hydrograph for December 2010 flow event 12/18/20100:00 Doug Chin December 14, 2011 Page4 ... C Photo 1: Long Marsh Creek and May Creek confluence as viewed from the footbridge looking upstream (August 2010). In Photo J in August of 2010, gravels from Long Marsh Creek are visible at the confluence with May Creek. These gravels are very similar in size and type (including glacially derived gravel) with gravel observed upstream in Long Marsh Creek between the culvert under SE May Valley Road and the confluence. Grass and vegetation is present outside of the active channel downstream of Long Marsh Creek. . . ' Doug Chin December 14, 2011 Page5 Photo 2: Long Marsh Creek looking downstream towards the confluence with May Creek (December 2010). The image in Photo 2 is from a video taken of Long Marsh Creek looking downstream to the confluence with May Creek. The red alder in the right side of the image is the same tree as in the left side of Photo 1. The flows were receding on December 12, 20 IO when Photo 2 was recorded . Photo 3 shows that although May Creek flow is not impeded by the lower cord of the foot bridge, flood waters leave the channel upstream of the footbridge and flow south of the foot bridge in the pasture. Observations of the conditions showed that Long Marsh Creek introduces higher flow velocities in the main May Creek channel at the confluence. In May Creek higher upstream velocities were occurring outside of the excavated channel on the south side of the valley. May Creek is occupying the lower elevations in May Valley. Doug Chin December 14, 2011 Page6 Photo 3: The confluence of May Creek and Long Marsh Creek during the December 2010 storm. Conclusions A. Based on the modeling and observations of the two creeks, stream flow and sediment deposition (bed load) is occurring in the following sequence during flood events: I. Flow volume increases in May Creek. 2. Long Marsh Creek enters May Creek higher on the alluvial fan. 3. Sand and gravel sized sediment from Long Marsh Creek is deposited higher on its alluvial fan and farther from the May Creek channel. 4. As flow volumes increase in May Creek, the creek overflows the channel above the confluence with Long Marsh Creek and shear stress decreases at the confluence as flood flows are distributed across the valley floor. 5. As flood waters recede in May Creek, Long Marsh erodes sediment deposited in the channel at the flood confluence and carries it to the next intersection with May Creek flood waters and eventually to the main channel. 6. Flow from Long Marsh Creek entering May Creek is higher velocity and is contributing to sediment movement in May Creek. •. Doug Chin December 14, 2011 Page 7 ) B. Between flood events, grass and vegetation establish on the new sediment deposits on the right bank of May Creek. C. During low flows in May Creek, Long Marsh Creek moves gravel to silt sized material to May Creek. D. Sediment from Long Marsh Creek during higher flow events is being deposited on top of existing vegetation, visible in patches under sediment. The foot bridge is not the predominate cause of backwater effect at flood events below the 2 year event, but requires a 5-year event to mobilize even if the footbridge was not there. Sediment deposition from Long Marsh Creek produces higher elevations in the May Creek channel and the backwater effect forces water out of the May Creek channel upstream of the foot bridge. This action starts a cycle of reduced sheer stress in the May Creek channel, further deposition by Long Marsh Creek and greater overbank flooding by May Creek. It should be noted that sediment size analysis from the confluence of Long Marsh Creek and upstream and downstream of the 146 1h Avenue SE bridge in May of2010 show similar well graded gravel sediment size distribution (King County Materials Laboratory 2010). The sediment sizes are similar because: I. The gravels found at Long Marsh Creek confluence and at the 146 A venue SE Bridge are representative of the May Valley glacial recessional deposits and the layer of finer sediment and muck is representative of the post glacial and human agricultural activities. 2. The flows contributed by Long Marsh Creek are enough to keep the muck in the May Creek channel from accumulating. References King County Materials Laboratory. 2010. Particle Size Evaluation of May Creek Water Channel Soils memorandum from Timothy R Hyden via Alan D Corwin to Jeff Burkey. May 11, 2011. . ' Memo To: Rebekah Padgett, 401 Coordinator, NWRO-SEA Erik Stockdale, Wetlands/ 401 Unit Supervisor, NWRO-SEA From: Patricia Olson, PhD, LHG Senior Hydrogeologist, SEA-HQ CC: Jeannie Summerhays Regional Administrator, NWRO Brian Lynn, Shorelands Manager HQ Date: May 22, 2012 Re: May Creek Dredging Project Summary Increased bank erosion due to May Creek project appears to be the greatest concern for the downstream property owners. I used the bank stability and toe erosion model (BSTEM Version 5.2, Simon and others 2008, http://www.ars.usda.~oy/research/docs.htm?docid-S044) to evaluate bank erosion under pre-project and post-project high flow conditions and possible increased duration of high flows. The BSTEM model shows that bank erosion occurs under existing flow conditions. The lateral bank retreat estimated by the model is within the range of the observed bank retreat indicating that the model is adequate to evaluate different flow and duration scenarios. The results indicate that post-project increased flow and duration conditions may increase bank erosion by approximately 2 cm for the 1-year peak flow event and less for higher magnitude peak flow events (Tables 1 and 2). However, this amount is within the model error so may be meaningless. My conclusion is that the May Creek project will not likely create a measurable increase in bank erosion. The conclusion is based on field site observations, additional data supplied by King County as requested by Ecology, and the BSTEM analysis. These data and analyses are described in more detail below. Introduction On April 2, 2012 Erik and I met with staff from King County and Renton and 3 landowners at May Creek ravine properties owned by Mr. Duffus and Mr. Coates. At the meeting. I requested some additional information from King County including pebble counts at station 3, modeled discharge pre and post event in excel spreadsheets for two wet years, and the link to the King County gage just downstream of the site. I told King County that if they wanted it reviewed with comments before later May, they would have to send the information to me before I left on vacation from Aprill 9-May 6. I received the link to the updated King County gages on Monday, April 09, 2012 and the pebble counts on 4/12/2012. But I didn't receive the modeled discharge data until after I was on vacation (4/23/2012). These data were very important to the analyses I did. For my first week back, we were teaching the O HWM class (2 days) and the remaining time I was preparing for teaching. On May 11, 2012 I began evaluating our field observations and provided data for May Creek and running a bank stability model which King County should have done initially. Bank erosion appears to be the greater concern for the downstream property owners. Bank erosion is a function of fluvial erosion, bank failure, weathering. piping or sapping. Although Pa tricia L Ol son, PhD, LHG , Eco lo gy 1 EXHIBIT 24 ~ bank mass wasting (slumping) occurred on the Coates property in January, fluvial erosion appears to be the dominant bank erosion process. During our April 2, 2012 site visit, the stream mean daily discharge was 32.7 cfs (stage 1.97 ft) at the King County stream gage 37H -May Creek at 143 Pl SE. This gage is located by the Illwaco Bridge, just upstream of the Coates and Duffus properties. There was no evidence of sediment transport or bank erosion occurring at this flow. In comparison on July 26 2011, the day of our first site visit the discharge was 1.59 cfs (stage 1.2 feet) (Photos la and b). The 4 days preceding our site visit on April 2 had 1.81 inches of rain (King County precipitation gage 37w) with half of that on March 29 which increased streamflow from 16.6 cfs to 43.8 cfs (Figure 1 ). A larger rain event ( 4.5 inches) occurred March 10-16 resulting in a maximum hourly peak flow of 127.25 cfs on March 16. Flows between the 1-year (68 cfs) to 1.15-year (125 cfs) peak flood were sustained for 47 hours (Figurel). This falls within the normal duration for these small, frequent floods. Bank erosion or bedload transport may have occurred during this small flood but we don't have that information. Photo 1: a) View of right bank on Duffus property on 4/2/12. Mean daily discharge was 32.7 cfs (stage 1.97 ft) at the King County stream gage 37H · May Creek at 143 Pl SE. b) View of right bank on July 26 2011, the day of our first site visit Mean dally discharge at the same gage was 1.59 cfs (stage 1.2 feet). Arrow show the cobble by the lowest bank pins on both photos. Patricia L Olson, PhD, LHG, Ecology 2 May22,2012 . , 130 120 110 100 _ 90 f g,. 80 ~ .. '§ 70 0.68 'i:i ~ 60 .54 :, 0 :c so 40 30 20 10 0 0 0 0 0 0 0 0 0 0 N N N " " " ---~ 0 " " " M --M M 1.11 1.07 . 3/15/2012 14:0 69.2 els 0 0 0 0 0 0 0 0 0 0 0 0 N N N N ,:! " " " ---N M .. "' " " " " ----M M M M 0.31 0.15 0.09 0 0 0 0 0 0 0 0 0 N N N " " " ;;, --~ w " " " ---M M M 0.73 3/19/2012 1:00, 69.84 els 0.61 0.48 0.3 0.28 0.16 0.12 0.03 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 9. 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 N N N N N N N N ~ N N N N N N " " " " " " " " " " " " " " -------;;, -------m 0 " N M .. "' ~ w m 0 " " N " N N N N N N N N N N M M ---------------.. .. M M M M M M M M M M M M M Figure 1: Hourly discharge and daily precipitation (inches) preceding and during site visit, King County stream gage 37H May Creek at 143 Pl Sand King County precipitation gage 37w-upper May Creek. Patricia L Olson, PhD, LHG, Ecology 3 May 22, 2012 1.3 1.2 1.1 1 > .. 0.9 " ~ " "' 0.8 ; .c u 0.7 .5 i 0.6.1; ·" "' 0.5 ·2 ~ CL 0.4 0.3 0.2 0.1 0 0 9. 0 N " -M -.. • • Evaluation King County included a bedload sediment transport analysis for the May Creek ravine in their May Creek dredging project reports. However, a bank stability model was not included in the analysis. The bedload sediment transport does not answer questions concerning bank erosion. Bank erosion appears to be a more important issue for the stream reach that fronts the Coates and Duffus properties. Rip rap ( cement blocks) was placed along the Coates property but it is failing and will need to be replaced by different bank stabilization. There is no bank stabilization along stream right on Duffus property. The property owners are concerned that the upper May Creek project will cause additional bank erosion. In my internal memo dated 8/15/20111 discussed the sediment transport concerns mostly focused on lack of adequate information to determine if the project will increase bank erosion: "Since the sediment transport study and the H and H study appear to rely on reconnaissance site level data that does not include adequate sampling points, I cannot make a determination concerning potential for increased bank erosion downstream of the project area. There are many factors affecting bank erosion in the downstream reach such as riprap focusing flow against unprotected banks, reduction in natural sediment source from bank erosion, and head cutting from response to glacial lowering of the base level and more recent lowering of base level when Lake Washington water levels were lowered for transportation purposes." Much discussion including meetings with King County, additional information from King County and a site visit with the property owners present has occurred since that memo. Questions concerning bank erosion were still not addressed. In order to be more proactive I conducted a general bank and toe stability analysis. There are caveats with this analysis: o The specific geotechnical properties for the banks are not available so the default values are used. o While I am a fluvial geomorphologist and hydrologist, I am not an engineering geologist or geotechnical expert My conclusions are based on my knowledge and experience with bank erosion, on-site observations and the models but an engineering geologist or geotechnical person should review these also. The analysis used the Hydrology and Hydraulic (December 201.0) study projections for increases in frequency and duration for smaller floods (Table 8, pp 47-48, Table 9) due to the project. For example, the 1.01 year flood (67 cfs) and 1.11 year flood (118 cfs) frequency of occurrence will increase by 16% and 10% respectively. The 2-year event, often considered a surrogate for effective discharge where data are not available, frequency will increase by 5%. I also used the pebble count data from section 3 of the sediment transport study to estimate some of the particle sizes for the bank stability model as well as soil data from SSURGO (NRCS soil surveys). Jeff Burkey, King County, supplied storm excursion data and hydrographs which were for 2 wet years which compare existing flows to simulated flows post project. These data were used in the analysis. I used the bank stability and toe erosion model (BSTEM Version 5.2, Simon and others 2008, htt;p://www.ars.usda.gov/research/docs.htm?docid=S044) to evaluate bank erosion under pre-project and post-project high flow conditions and possible increased Patricia L Olson, PhD, LHG, Ecology 4 May 22, 2012 duration of high flows. BSTEM incorporates pore-water pressure distributions ( saturated and unsaturated conditions), layering. confining pressures, reinforcement effects of riparian vegetation and complex bank geometries to solve for the factor of safety. The model quantifies bank shear strength (resistance to bank failure: geotechnical processes), bank-toe erodibility (resistance to toe erosion and steepening: hydraulic processes), and the effects of stabilization measures on these processes (roughness, root reinforcement, transpiration). The model calculates lateral bank retreat, bank erosion volume and erosion profile from toe or lower bank erosion. While there is a upper bank failure on the Coates property, right side stream bank erosion on Duffus property occurs mostly by toe erosion and stream bank undercutting. The BSTEM toe erosion model was primarily used to estimate bank retreat under different peak flow scenarios. The bank stability model was only used to evaluate the Factor of Safety (FS) from toe erosion model output for 2 groundwater levels. Iterative Modeling Scenarios I used the BSTEM model runs to establish bank retreat rates during 3 flood events for existing bank and vegetative conditions. The 3 events were chosen based on King County modeling that shows there will be an increase in flood magnitude and duration (Tables 8 and 9 in the Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project, 12/17/2010). I then ran 2 other scenarios for each peak flow to evaluate the average and maximum increase in flood event magnitude and durations due to the project for the 3 peak flows: o Existing flows and duration for 3 peak flow events for o 1-year annual peak flow event ( 68 cfs, average duration 46 hours) o 1.25 year annual peak flow event (149 cfs, average duration 18 hours) o 2-year annual peak flow event (229 cfs, average duration 2 hours) o Average increase in flood event magnitude and duration from project (Table 1) for o 1-year annual peak flow event (78 cfs, average duration 52 hours) o 1.25 year annual peak flow event (161 cfs, average duration 24 hours) o 2-year annual peak flow event (240 cfs, average duration 3 hours) o Maximum increase in.flood event magnitude and duration from project (Table 2) o 1-year annual peak flow event (82 cfs, average duration 52 hours) o 1.25 year annual peak flow event (175 cfs, average duration 24 hours) o 2-year annual peak flow event (240 cfs, average duration 3 hours) Since geotechnical testing of bank material for model parameterization has not been done, nor are we responsible for doing a geotechnical analysis, I used the default parameters contained within the model. The parameters such as slope, bank angle and bank material were conservative meaning that they estimate higher lateral bank retreat For example, the bank material is more cohesive than the bank materials I used in the model and the model channel slope is greater than the channel slope along the bank For example, channel slope is an important variable in calculating shear stress and bank erosion. A higher channel slope will increase shear stress and bank lateral retreat Both Patricia L Olson, PhD, LHG, Ecology 5 May 22, 2012 • factors provide more conservative (higher) lateral bank retreat estimates. Figures 2 and 3 show parameters used and the default bank material characteristics. Water depth for each flow was estimated from the stage-discharge relationship at King County stream gage 37H May Creek at 143 Pl SE. The water depths estimated by the gage stage-discharge curve were similar to those estimated for cross-sections near the bank site by the HEC-RAS analysis indicating that the water depths estimated from gage information were suitable for this analysis. ---p-affllrvonm • .. o·.;;;;;;;;;·'r; .. ..,--:i s Option I\ • Dr.,, • dt"t.a.d b1nk Option B • Ent•r • b.lnk h,ight ,nd .angl,, C '"" Q . , R-U-bf1!oJaiofWpaon bonktoo !. = .u proru. using tht botH ~w tM model win gtnM at, ,1 b,1nk profit, -(d no hraob of Cpa then ""'' v~-. intertHin.t.QrmodiAry C Option A Q Optlo.B w polnta} . -, Station El...,Mion V •bHeofbnnktoa · , ' Point (ml (ml L 2.4 i •} Input b1nt. h•Jghl (m) vi-ondpo~t{typi=tyinidi,ont J Top ofehannol') -: • 0.00 I 2.40 ltoet? ( 82.0 , b J Input b•nt. •ngl• (') ., ~~y B 240 I 2.40 I I • C 2.42 I ,.,. I r: j 0.3 I c) Input b1nk ,o, ltng1h (m) Sb:ation (m) Noto,: ' . 0 244 I '·" I r: , . Bankp,orw:»ni::l}'overhan;. 1 I I r:: I 2!5.0 ! d) Input bank tot •ngt, (') """" -.i lfthab°"kpm<e,lsMy ' E 2.46 "' . mammu \ --popubtltd, the lhaar..ulfaca F 248 I too I r: G '" I "' I r:: . ~:l~nce point should be 9 j -· . o .,. be'lwellfl'ftn:t'l11 B.ond 1 H 2.1!13 I t50 I l'l I I IJ j _J Input shtar surf.act .nglt 3 I , ... t3" J 2.1!17 I 1.19 I I" K 2.!59 I to4 I l'l 2.5 L 2.61 I 0.8S I l'l Bank layer thlcknesa (m) M 2.83 I 0.74 I l'l fltHliOft of 2 N 2.615 I 0.15S I LJ ~rNH ~ 0 2.61 I 0.43 I IJ TQOU,W{.,) z 1.5 IJ I o.,o I Q 0 p 2.70 I 0.2S I L•y•r 1 t90 l ~ Q 2.72 I 0.14 I p > 1 I I L•yitr 2 ( 0.60 I 1 w R 2.78 0.11 1.30 ~ • , ... I .... I f w • •• T 2.90 I 0.06 I '''"' Loru 0.70 ' u ,., I 0.03 I J 0 " • 3.02 I 0.00 I La1tr 4 I 0.30 I 0.40 " -~ ~ .J '''". j 0.40 I 0.00 .().5 . ShHr .rntor~• ,i.v (__9-.;{j ..... 0 1 2 3 ' 5 I -STATION(M) ShHI SI.Jf•c• ang1• 63.78 J --.. .. . --. --· -r ---•~s --- Channel and flow parameteni : (:J[_j tnputrHchltongth(m) View !Banllt ' Run Bank ( O.OOS 1 Input rHch sloi,. (mhn) (_ol[j Input ,1-tlon of fl°" (m) Geometuy I Geometry Macro (~ Input duration of Row (hrs) ' ' Figure 2: Channel slope= 0.009, bank height= 2.4 m, bank angle (degrees) 82°, toe length=0.3 m, angle 25°, Layers 1-3-coarse sand, layer 4-gravel, layer Sand toe-cobble (see Figure 3). Water depth for post project 1-year peak flow event (68 cfs) Is 0.65 m and duration is 46 hours (also refer to Table 1). Patricia L Olson, PhD, LHG, Ecology 6 May22,2012 Select material types (or select "own data" and add values below) Bank Material Layer 1 Layer 2 Layer 3 LSyer 4 Layer 5 lco..-,.ro..-.ded,8 1Fileroundedsonc8 lcoorsoqulars,:::J 1Gr•vel i2J !cobbles ___ E] Bank and bank-toe material data tables. These are the default parameters used in the model. Changing the values or descriptions will change the values used when selecting soil types from the list boxes above. Add your own data using the white boxes. Material Descriptors Bank Model Input Date Bank Toe Material I Cobbles __ !2] ., Chemical Bank material type Description Mean grain size, D,a {m) Friction angle ;' (degrees) Cohesion c' (kPaJ Saturated unit weight (kN!m 3) ,° {degre~j concentration 1 2 3 4a and 4b Sa and Sb Ga, Gb and 6c 7a. 7b and 7c 8a, 8b and 8c Boulders Cobbles Gravel Angular sand Rounded sand Silt Soft clay Stiff clay 0.512 0.128 0.0113 0.00035 0.00035 42.0 42.0 36.0 36.0 27.0 30.0 25.0 20.0 0.0 0.0 0.0 0.0 0.0 3.0 10.0 15.0 20.0 20.0 20.0 18.0 18.0 18.0 18.0 18.0 15.0 15.0 15.0 15.0 15.0 15.0 15.0 15.0 (kg,l<g) ' 1 l ! Own data layer 1 f::: =====:, :::f ===11::===~I ~I =~I :::f ==::;I C I I II If 11 ID 9 Own data layer 2 Own data layer 3 Own data layer 4 Own data layer 5 =f==~I II II II I~ OWn data Bank Toe I I II II II 19 I 11 11 11 If I ~--~ Need to know the crltlcol shear stress l'lc) ? Need to know the erodlblllty coefficient (k)? Input non-cohesive particle diameter (mm) I 11.000 I Input critical shear stress r, (Pa) I 10.690 Critical Shear Stress fc (Pa) I 10.69 I Erodibility Coefficient (cm'JNs) I 0.031 Figure 3: Bank material types by layer and default model input data for all scenarios. While only default soil geotechnical properties were used the bank profile and lateral bank retreat calculations look reasonable based on site observations and photos (Figure 4). Modeled bank lateral retreat under existing conditions was within the range of bank retreat measured from the bank pins on 4/02/12. At the eroding bank on river right just downstream from the Coates property, the lowest pin indicated that approximately 7.6 cm (3 inches) lateral bank retreat occurred and the middle pin had approximately 8.9 cm (3.5 inches) lateral bank retreat An approximate 1-year to 1.15-year peak flow event occurred from 3/15-3/19 /2012. The maximum hourly peak flow was 127.25 cfs at 6:00 pm on March 16. Flows between the 1-year (68 cfs) to 1.15-year (125 cfs) peak flood were sustained for 4 7 hours. This duration is the average duration for the 1-year peak flow. The BSTEM model estimated that 6.7 cm oflateral bank retreat could occur at 68 cfs sustained for 46 hours (Figure 4, upper graph, Table 1 ). The observed bank erosion may have occurred during this high flow but we don't have that information. Patricia L Olson, PhD, LHG, Ecology 7 May22,2012 I I ~~~~~~~;fj·'~1~~~;~~~/~~;:~~1~j~:~:~~c~~ ,t~ ~~,ft·:~~~,~,1£z~;~z~t~tt.~~~i~;~ 6.6'1:.¥~ ~ l'}.!l!ldW~.l'ilRllJtfill~ ~~mg~_¢ <i~~-'..':"&!;.J\ ~~!ll151_ 'i'0. ,~:~'<'_~r. !MllifJ ~.~~.:Jl% .. 7"a,.·•;<.;::,:z,:._-,--'. .·_'<~'.,;.<f·,f'.;.;_,_-·ll '"" . . .' .. ;,.,--. .--·--,.,, ·-· -.--·-,. . '· ' _ ... ,_., .. -', '., .. "·' Bank Uamna1 Bank Toe UatsrlaJ Layer 1 Layer 2 Layer J Layer 4 Layer 5 I Coarsesand_;j Finesand__jj_ Coarsesand _;j_ G~----'1 Cobbles __ :[_Cobblea """""' O.!iO __ d _o,1J 1L_ osq _ii __ 11.00 __ ;I 124~? !I. 1244? Critical shear strea (Pal 111 0.141 Ii O 282 11 0.141 j j O.OJO II O 009 ii 0.009 j Erodibillty Coefficient lcm3/N5) 3.00 ~------------------~ '"' >------~ ,.oo 1------1- ~-50 is " ~-~,.-1--------t--:-===-:-----'·"' --------•----- 000 +-______ _,. ________ _ --Bue of layer I --Base ofll)ler 2 --But of layer 3 --Bue of layer, --Bue OflBft( 5 --Eroded Profllo -w-=-Slirfaee .0.60 --tmt11IProffle 0.00 1.00 2 00 3.00 ... 00 5.00 6.00 7.00 STATION(M) Senk Ueterial I !Run l'oe-lErosion Model A\11rage applied boundary shear stress Maximum Lateral Retrsat Eroded Area -Bank Eroded Area • Bank Toe Eroded Area • Bed Eroded Alea · Total ( 36_450 __ 1 Pa L_ 6.729 _cm I _0.010 •m2 I. 0.000 ~m2 I o_ooo ____ :m 2 L _ 0.010 ___ m' Export New (Eroded) Profile into Model Bank Toe Material !!t!,r 1 [ Coarse sand Layer 2 Layer 3 Layer 4 Layer 5 J i. . F~ ~ __ !( Coarse sand ' I ~I _ _ L _ Cobb!": _ . ,[ . . _ <;~_ j Uaterlal ~ I __ o.n __ 1 I. o.so _..., I 11.00 __ I_ 124.42 I._ __0.50 --ii. 124 42 Crltlcal shear Ares, ------(Pa) I o.141 11 0282 11 o.141 11 o.o,o 11 o.oo, 11 0.009 j Erodiblllty Coeffldent 3.00 .-----------------, 2.50 1------, 2.00 1------1- &so 2 0 ~ ~1.00 t-----'t------ ''°1---~t--- 000 ;-------''-------- --Bue ort,rer 1 --Bue ofl,ylll" 2 --e.s, ofl,yer 3 --Bue ofl,yer" ---Bne ofl•-,e-5 --Erodt"d Pro!le -wamsumce .050 --lnllialPl'oflle 0.00 1.00 2.00 3.00 ,.oo 5.00 6.00 1.00 STATION(MJ lcmJ/Jb) Run li"oe-lErosion ~oolel Average applied boundary shear strass Maximum Lateral Retreat Eroded Ania • Bank Eroded M1i1 -Bank Toe Eroded Area -Bed Eroded Area -T otsl I 3t_S60 ~Pa j 8.778 ,cm I . o.o1J -m• I 0.000 .m• I 0.000 m• '-~-~m2 ---··· - Export New (Eroded) Profile into Model 3 2.5 2 ! ~ 1.5 6. 7 cm lateral j bank retreat , w ore oroiect ! ~ .. 0.5 0 .0.5 0 , 2 3 STATION(M) 2;1 2 ~ z 1.5 8. 78 cm lateral 0 !i 1 bank retreat, i::i oost oroiect ... w 0.5 0 -1 0 1 2 3 STATION(M) Figure 4: upper graphs show the estimated toe erosion from 1-year peak flow pre project and the bank profile. The lower graphs are for the 1-year post project under average discharge and duration increases for post-project conditions. Patricia L Olson, PhD, LHG, Ecology 8 May22,2012 • • e 4 5 Table 1: Existing flows and duration for 3 peak flow events for pre project compared with BSTEM results for the same 3 peak flows with the average increase in flood event magnitude and duration from project Flow class Discharge Water Duration Shear Ground Factor Lateral Change event (cfs) depth (hrs) stress water of retreat in (m) level safety (cm) retreat below (cm) toofm) 1 Pre 68 0.65 46 36.45 1.0 0.31 6.73 year oroiect 2.0 0.82 Modeled 78 0 .67 52 37.16 1.0 0.25 8.78 2.05 oost 2.0 0.72 1.25 Pre 149 0.74 18 42.02 1 .0 0.22 4.22 yr project 2.0 0.8 Modeled 161 0.75 24 40.3 1.0 0.35 5.63 1.4 oost 2.0 0.87 2-yr Pre 229 0.78 2 42.35 1.0 0 .23 0.70 project 2.0 0.81 Modeled 240 0.79 3 43.04 1.0 0.23 1 .14 0.44 oost 2.0 0.82 Table 2 Existing flows and duration for 3 peak flow events for pre project compared with BSTEM results for the same 3 peak flows post project maximum Increase in flood event magnitude and duration Flow event 1 year 1.25 yr 2-yr class Discharge Water Duration Shear Ground Factor Lateral Change (cfs) depth (hrs) stress water of retreat in (m) level safety (cm) retreat below (cm) too (m) Pre 68 0.65 46 36.45 1.0 0.31 6.73 oroiect 2.0 0.82 Max 96 0.68 52 37.71 1.0 0.25 8.79 2.1 post 2.0 0.72 Pre 149 0 .74 18 42.02 1.0 0.22 4.22 project 2.0 0.8 Max 181 0.76 24 40.03 1.0 0.24 6.15 1.8 oost 2.0 1.01 Pre 229 0.78 2 42.35 1.0 0.23 0.70 project 2.0 0.81 Max 240 0 .79 3 43.04 1.0 0.23 1.14 0.44 post 2.0 0 .82 The BSTEM model shows an approximate 2.1 cm increase in lateral bank retreat for the 1- year flood. As floods get larger, the difference between modeled lateral bank retreat pre and post project decreases. The model error is greater than 2 cm, so no conclusion can be reached on the 2.1 cm increase. This is particularly the case since the parameters used are conservative that is higher channel gradient and less cohesive bank materials in particular. Patricia L Olson, PhD, LHG, Ecology 9 May 22, 2012 There are other factors which may reduce bank erosion rates as estimated in the model such as groundwater levels, rate of point bar deposition, and the streams capability to erode the bank toe. Groundwater level Groundwater or saturated subsurface water creates a positive water pressure which increases bank erosion potential. Unsaturated subsurface water conditions produces negative water pressures which reduces bank erosion. The groundwater levels are not known for this area but there was no evidence of groundwater seepage on the bank on 4/2/2012 even though a larger rain event ( 4.5 inches) occurred March 10-16 resulting in a maximum hourly peak flow of 127.25 cfs (Photo la, Figure 1). The 4 days preceding our site visit had 1.81 inches of rain (King County precipitation gage 37w) with half of that on March 29. Since the groundwater level is not known, I used 2 scenarios: a relatively shallow groundwater level at 1 meter below the bank top and a 2 meter groundwater level (Tables 1 and 2). Both are very conservative for the observed site conditions. The shallower groundwater level had a lower Factor of Safety (FS) than the deeper groundwater level (Tables 1 and 2). The FS decreases slightly for both cases when the 1- year peak flow and duration are increased and increases slightly for both cases when the 1.25 and 2-year peak flow and duration are increased. These results are only relative because the FS calculated by the BSTEM model indicates that the bank is unstable (FS<1.0) for the pre-project flow conditions as well as post-project (Tables 1 and 2). But we already knew that to be the case. The question is: "Does bank stability (FS) decrease between pre project and post project significantly?" Under all 3 flow conditions : existing, average increase, and maximum increase, the FS changes only slightly indicating that bank instability, within model constraints is not greater post project (Table 1 and 2). Rate of deposition of the point bar If deposition on point bar lags bank erosion, then the channel may widen over point bar decreasing bank erosion. When the bar deposition increases to where the channel narrows than bank erosion will increase. Observations and photos of the point bar suggest that the former case where channel widening during higher flows occurs at this site (Photo 2 a and b). Patricia L Olson, PhD, LHG, Ecology Photo 2: a) Point bar forming on river left across from eroding bank during low flow (1.6 cfs) b) point bar Is submerged at 32.7 ds indicating that during higher flows the channel widens which can decrease bank erosion. 10 May 22 , 2012 . . " . Streams ability to erode or remove the bank toe materials (gravel to cobble size) The bank toe material at this site is gravel-cobble dominated. If the stream can remove the cobbles at flows that are influenced by the project, than bank erosion rates will increase. If not then the cobbles will protect the bank toe from increased erosion due to changes in high flow magnitude and duration as estimated for the project The thalweg does not follow the bank but is more in mid channel location between point bar and bank toe. Thus the higher stream power will occur in mid channel and not along the bank Conclusion The BSTEM model shows that bank erosion occurs under existing flow conditions. The lateral bank retreat estimated by the model is within the range of the observed bank retreat indicating that the model is adequate to evaluate different flow and duration scenarios. The results indicate that post-project increased flow and duration conditions may increase bank erosion by approximately 2 cm for the 1-yar peak flow. This retreat decreases as the flow magnitude increases because of the relationship between water depth and groundwater levels. The 2.1 cm retreat is less than model error so may be meaningless. Based on data supplied by King County, field observations and the BSTEM analysis, I don't think that there will be a measurable increase in bank erosion that could be attributed to the project However bank monitoring program should be maintained. If there appear to be increases than King County should conduct a geotechnical analysis of the bank materials and use a bank and toe stability model which integrates those measured properties. Model references Pollen-Bankhead N, Simon A 2009. Enhanced application ofroot-reinforcement algorithms for bank-stability modeling. Earth Surface Processes and Landforms 34( 4): 471-480. DOI: 10.1002/esp.1690. Pollen N, Simon A. Collision AJC. 2004. Advances in assessing the mechanical and hydrologic effects of riparian vegetation on streambank stability. In: Riparian Vegetation and Fluvial Geomorphology, Water Science and Applications 8. Bennett S, Simon A (eds). AGU: Washington, DC; 125-139. Simon A, Collison AJC. 2002. Quantifying the mechanical and hydrologic effects of riparian vegetation on streambank stability, Earth Surface Processes and Landforms 27(5): 527- 546. Simon A. Curini A 1998. Pore pressure and bank stability: The influence of matric suction, In Abt SR, Young-Pezeshk). Watson CC (eds.), Water Resources Engineering '98, ASCE: Reston; 358-363. Simon A. Curini A, Darby SE, Langendoen EJ. 2000. Bank and near-bank processes in an incised channel. Geomorphology 35: 183-217. Simon, A., Derrick, D., Alonso, C.V., and Pollen-Bankhead, N. (2008). "Application of a deterministic bank-stability model to design a reach-scale restoration project," In: R.W. Babcock, Jr., and R. Walton, (eds.), Proceedings of the World Environmental and Water Resources Congress 2008 Ahupua'a, May 12-16, 2008, Honolulu, Hawai'i, ASCE. Patricia L Olson, PhD, LHG, Ecology 11 May22,2012 STATE OF WASHINGTON DEPARTMENT OF ECOLOGY Northwest Regional Office 3190 160th SE Bellevue, Washington 98008-5452 (425) 649-7000 June 14, 2012 Doug Chin King County Department of Natural Resources Water and Land Resources Division 201 South Jackson Street, Suite 600 Seattle, WA 98104-8355 RE: May Creek Dredging Project Dear Mr. Chin: In an email dated June 5, 2012 you posed four questions, which I would like to answer, as follows: 1. Does Ecology agree that the existing erosion problem downstream will not be aggravated by the May Creek Drainage Improvement project? Ecology's Senior Hydrogeologist (Dr. Patricia Olson) recently authored a report dated 5-22- 2012 (attached) that concludes that the May Creek project will not likely create a measureable increase in bank erosion downstream from the project site. She based her conclusion on field observations, additional data supplied by King County, and a bank stability and toe erosion model. We believe her analysis answers the questions we raised regarding the potential downstream impacts from the May Creek dredging project. 2. Does Ecology support the proposed 15-foot fenced buffer along May Creek and the proposed wetland enhancement on the Stonegate property as mitigation for project stream and wetland impacts? Yes. We will accept the planting and fencing of a permanent 15-foot wide buffer on both banks of May Creek, as well as the Stonegate property wetland enhancement, as adequate mitigation for the stream and wetland impacts related to the May Creek dredging project. This is in addition to proper implementation of construction-phase water quality management practices. As we discussed during our meeting earlier today, the project wjl) not sufficiently improve or adequately address the water quality degradation that is occurring as a result of the poor pasture and manure management practices on the adjacent properties. We hope to address those concerns in the near future in collaboration with King County and the King Conservation District (as discussed earlier today). We have invited the Conservation District to apply for "Direct Implementation Funds" to help pay for the BM P's to address the water quality problems. 3. Does Ecology agree that King County has adequately addressed all other concerns originally raised in Ecology's August 15, 2011 internal memo written by Patricia Olson and the Ecology's letter dated September 1, 2011? King County response letters were provided on February 9, 2012 and September EXHIBIT 24 ti Doug Chin June 14, 2012 Page 2 16, 2011, respectively. In addition to the written responses, King County met with Ecology staff on October 18, November 14 and 15 of 2011, and April 2, 2012 to discuss King County's analysis and evaluate site conditions. Yes, when considered in context of the additional analyses conducted by Dr. Olson and reported in her May 22, 2012 report 4. A separate question that was not raised by Ecology, but King County would like input on is the question of existing downstream flooding. Does Ecology have any concerns regarding the existing flooding problems downstream? No. We are not aware of downstream flooding problems. Please contact me if you have any questions, at 425-649-7061 or erik.stockdale@ecy.wa.g:ov. Sincerely, Erik C. Stockdale, PWS Wetlands/401 Unit Supervisor cc: Jeannie Summerhays Geoff Tallent Rebekah Padgett Patrick McGraner Patricia Olson .;,· .,, King County Road Services Division Department of Transportation KSC-TR-0231 . 201 South Jackson Street Seattle, WA 98104-3856 .August 1, 2012 TO: Doug Chin, Senior Engineer, Water and Land Resources Division, Department of Natural Resources and Parks FM: Julia Turney, G~ LG 2493, Environmental Unit, Road Services Division, Department of Transportation and John B gineering Geologist LEG 1300, Water and Land Resources Divi , partment of Natural Resources and Parks RE: May Creek Drainage Improvement Project-SE May Valley Road Review of Bank Stability and Toe Erosion Model Geo technical Default Values Introduction Dr. Patricia Olson, of the Washington Department of Ecology, used the Bank Stability and Toe Erosion Model (BSTEM V 5.2) to evaluate bank erosion under pre-project and post- project high-flow conditions. In her analysis she noted that geotechnical default values in the model were used and recommended that an engineering geologist or geotechnical person review the model parameters. The City of Renton requested that King County respond to Dr. Olson's recommendations. This memo presents an evaluation of the geotechnical default values and how they compare to published variables. Discussion The input parameters and default variables from Dr. Olson's memo are noted below. Select material ty~s ( or select "own data" and add· values below) Bonk !-b,odi,I l&)'.(;t '• _ •~avu ~ :.a-"''E'r 3 Lsve-r A l<:.,..11~1,;r .. ·;d!,;<.J,3 lrme,c111~-.1e;:'!U,1"3 J~i.e~tig.t-:i :tl'i] l~=.,,d Bank and bank-toe material data tables. fh::se are tM<lef"Rul pa,.11nelt:1,s-ul!OO in !J1E model. i:hanghg lt,e ~'Sluas er U:'scritonswu·.;;hal'~fi the .._-.,fm,:; ut&cG '1-·hcn ::"e,ICct;n~ C(li· 1j·p:is frr.ni 1hn li,1 ~OY...-9 .ltO\\J". A1d y1;1v, t'i.V!t dm..; •.1t:ln.3 lhc·whi:c; bc-;,ll"t, fifatcrial Doa.:r!ptore. M~r;~r~;:,l · si:e:. G ~= {'n.1 ..... 1. · · · · · Ec;oh~~r~ · ri f 1!1 · .t?. a · u o· (:obble, Vr?:61 1 ·2e 4Z'.~1 o o o.o·.n 4aai.1d4o, }lng.ulars:m:1 tl.V'1H<J& ;R ;i."lrl 5~ Ri:u1nrlerl si;n{\ fi 00l3S ""· th anrl ~ Silt 7c. rb t'lnd 7( tot dov Ga. ~b arid 8t. S\i~,.cl"~ ·.tG.O l)_lj :!-ti.i.1 JJ.0 7.1 1) 00 ?ii ~1 30 25 ') 1(" 0 20-, 15.0 Bank L'lodcl l~u1 Doto 20.D 15 0 ill 1 15.tl 1fL"! Hi<l -m;, 1f. 0 18.) 15.0 1a.1 15" 8:i.nk iuo l.lutur A portion of Figure 3: Bank material types by.layer and default model input data for all scenarios. Doug Chin August I, 2012 Page2 The bank materials in the May Creek reach evaluated by DOE and Anchor QEA are mapped as undifferentiated glacial outwash. The materials are a mix of silt to gravel-sized sediments and appear to be recessional outwash. Dr. Olson used cohesionless sand to cobble-sized material to identify layers within the bank. Published geotechnical variables and fluvial erosion variables were obtained from the references listed below. The references were selected because the literature references Western Washington streams and investigations. The table below lists the variables and factors in the model and literature. Geotechnical Unit Western BSTEM Model 1 ·'· 0 Variables Washington Recessional Sand to Cobble Outwash Effective Friction degrees 30-403 27-42 Angle Effective kPa 0-483 0 Cohesion Saturated Unit kNm·• 21 4 18-20 Weight Matric Suction degrees Not available' 15 Angle In general the geotechnical factors· used in the model are similar or more conservative than the numbers found in literature for recessional outwash. Matric suction is not a readily available value for Western Washington. The value in literature is 10 to 20 degrees and the model defaults to a midpoint number in this range. Conclusion We agree that the default values in the model are reasonable for the bank materials. Reference Sources 1. Simon, A. et.al., 2011. Development of the Bank-Stability and Toe-Erosion Model (BSTEM Version 5.4) USDA-ARS national Sedimentation Laboratory, http://www.kwo.org/reports publications!Presentations/pp Development of BSTEM 01281 I sm.pdf 2. Midgley, T.L, 2010. Stabilty of Composite Streambanks: Modeling and Subsurface Flow Field Experiments, Submitted to the Faculty of the Graduate College of the Oklahoma State University in partial fulfillment of the requirements for the Degree of Master of Science. http://biosystems.okstate.edu/Home/gareyfi'Midgley Thesis.pdf 3.. Savage, W.Z., et. al., 2000. Geotechnical Properties for Landslide-Prone Seattle Area Glacial Deposits, United States Geological Survey, Open File Report 00-228 http://pubs.usgs.gov/of/2000/0228/report.pdf 3. Galster, R. W. ed., 1989, Engineering Geology in Washington, 406 p. • ,. Doug Chin August I, 2012 Page3 4. Shannon and Wilson Geotechnical and Engineering Consultants, 2006. Preliminary Engineering, Geotechnical Considerations Report for University Link, Prepared for Central Puget Sound Regional Transit Authority. http://www.globaltelematics.com/pitf/Geotech consideration reportUniversityLink.3.06.pdf 5. Note: Angle decreases with desaturation at higher motric suction. 15 degrees is half the value of the effective friction angle for recessional outwash-consistent with the default value. Rahardjo, H. et. al., 1995. Shear-Strength Characteristics of a Residual Soil, Canadian Geotechnical Journal, Volume 32. pg. 60-77. "http://www.soilvision.com/~ubdomains/unsaturatedsoil.com/Docs/Research%20Papers/l 99 5/Journal%20Papers/Shear%20strength%20characteristics%20of%20a%20residual%20soi1% 20with%20suction.pdf http://soilvision.com/subdomains/unsaturatedsoil .com/Docs/Rescarch%20Papers/ 1988/J ourn al%20Papers/Determination%20o:f%20the%20sheat'/o20strength%20parameters%20of%20a n%20unsaturated%20soil%20using%20the%20direct%20sheat'/o20test.pdf 6. Olson, P., May 22, 2012. May Creek Dredging Project, Washington Department of Ecology, Memo to Rebekah Padgett and Erik Stockdale. JT:mr cc: Don Althauser, Managing Engineer, Water and Land Resources Division (WLRD), Department of Natural Resources and Parks (DNRP) Jeff Burkey, Hydrologist, WLRD, DNRP Lindsey Miller, Environmental Engineer, Environmental Unit, Road Services Division, Department of Transportation STATE OF WASHINGTON DEPARTMENT OF ECOLOGY Northwest llegional Office • 3190 160th Ave Sf• Bellevue, WA 98008-5452 • 425-649-7000 711 for Washington Relay Service• Persons with ,1 speech disability can.call 877-833-6(/1 January 8, 2013 · rty of Renton . . Planning Division Doug Chin, Project Manager King County Water and Land Resources Division 201 South Jackson Street, Suite 600 Seattle, WA 98104-3855 FEB 1 2 1Ul3 RE: Water Quality Certification Order #9352 for U.S. Army Corps of Engineers Public Notice #NWS-20 I 0-158, May Creek Drainage Improvement Project, in Renton; King County, Washington Dear Mr. Chin: On June 20, 2012, King County Water and Land Resources Division submitted a Joint Aquatic Resource Permit Application (JARP A) to the Department of Ecology (Ecology) for a Section 401 Wate1· Quality Ce11ification (401 Certification) under the federal Clean Water Act for the above project. On behalf of the State of Washington, Ecology certifies that the work described in the JARP A and the public notice complies with applicable provisions of Sections 30 I, 302, 303, 306 and 307 of the Clean Water Act, as amended, and applicable state laws. This certification is subject to the conditions contained in the enclosed Order. If you have any questions, please contact Rebekah Padgett at (425) 649-7129. The enclosed Order may be appealed by following the procedures described in the Order. Sincerely, r;;-~,~ Erik Stockdale, Unit Supervisor Northwest Regional Office Shorelands and Environmental Assistance Program ES:rrp:cja Enclosure By certified mail: 7012 1640 0000 6245 9597 EXHIBIT 25 Doug Chin January 8, 2013 Page 2 of2 cc: Lori Lull, U.S. Almy Corps of Engineers Larry Fisher, Washington Department of Fish and Wildlife Karen Walter, Muckleshoot Indian Tribe Katie Bonwell e-cc: Patrick McGraner -NWRO Patricia Olson -HQ Loree' Randall -HQ Raman Iyer -NWRO ecyrefedpermits@ecy.wa.gov Jennifer Henning, City of Renton Jhenning@Rentonwa.gov Karen Walter, Muckleshoot Indian Tribe KWalter@muckeshoot.nsn.us Jean Rollins urbanseparator@hotmail.com Debra Rogers herogers@comcast.net Susan Malin. susiemalin@msn.com Gary Alnundson gary.a@comcast.net Andrew Duffus klassicars@hotmail.com Carol Tabacek caroltabacek@aol.com Mary Weirich maryvweirich@comcast.net A. Duffus blueheron6987@hotmail.com Julie Bonwell jbonwell@lesourd.com Mary Celigoy maryceligoy@comcast.net IN THE MATTER OF GRANTING A ) WATER QUALITY ) CERTIFICATION TO ) KING COUNTY WATER AND LAND ) RESOURCES DIVISION ) in accordance with 33 U.S.C. 1341 (FWPCA § 401 ), RCW 90.48.120, RCW 90.48.260 and Chapter 173-201A WAC TO: Doug Chin, Project Manager ) ) ) ORDER#9352 Corps Reference #NWS-2010-158 May Creek Drainage Improvement Project; Renton, King County, Washington. King County Water and Land Resources Division 201 South Jackson Street, Suite 600 Seattle, WA 98104-3855 On June 20, 2012, King County Water and Land Resources Division submitted a Joint Aquatic Resources Permit Application (JARP A) to the Department of Ecology (Ecology) for a Section 401 Water Quality Certification. A joint public notice regarding the request was distributed by the U.S. Army Corps of Engineers (Corps) for the above-referenced project pursuant to the provisions of Chapter 173-225 WAC on September 26, 2012. The drainage improvement work includes: . o Dredging: Remove sediment from 2,086 linear feet of the creek. A temporary access road includes placement of quarry spalls in 7,550 square feet of wetland, and replanting with native vegetation upon removal. o Vegetation Removal: Clear reed canarygrass and willows from 14,500 square feet of channel. o Sediment Management: Reconstruct 300 feet of Long Marsh Creek Channel and its confluence with May Creek for sediment storage, including excavation of290 cubic yards of material. Create a 100-foot side channel parallel to May Creek and joining Long Marsh Creek. · Mitigation for impacts to the creeks, permanent fill of approximately 0.48 acre of Category 2 wetland, and temporary fill of approximately 7,550 square feet of Category 2 wetland includes: o Installation of a 15-foot buffer of native riparian and wetland planting on both sides of May Creek (total of2.0 acres), an! !-foot buffer of native riparian planting on both sides of Long Marsh Creek, and a 6-to 8-foot buffer of native riparian planting on the notth side of the side channel. Fencing will be installed around the planting areas to minimize livestock access to the stream. o Enhancement of approximately 3 acres of wetland which would include construction of off-channel wetland alcoves along May Creek, reed canarygrass suppression, installation of 16 pieces of large woody debris and two snags in the off-channel wetland alcoves, placement of 45 cubic yards of streambed gravels in the reconstructed 300 linear feet of Order #9352, e,v1ps Reference #NWS-2010-158 King Coul1/y Water a11d Land Resow·ces Division January 8, 2013 Page2 o/19 Long Marsh Creek, placement of 60 pieces of large woody debris in the wetland enhancement w-ea, and planting of native vegetation. The project is located both upstream and downsll-eam of the 148 1h Avenue SE bridge in Renton, King County, Washington, May Creek and wetlands, Sections 2 and 3, T. 23 N., R. SE., WRIA 8. AUTHORITIES: In exercising authority under 33 U.S.C. § 1341, RCW 90.48.120, and RCW 90.48.260, Ecology has examined this application pursuant to the following: 1. · Confo1mance with applicable water quality-based, technology-based, and toxic or pretreatment effiuent limitations as provided under 33 U.S.C. §§ 1311, 1312, 1313, 1316, and 1317 (FWPCA §§ 301,302,303,306 and 307); . 2. Conformance with the state water quality standards contained in Chapter 173-201 A WAC and authorized by 33 U.S.C. § 1313 and by Chapter 90.48 RCW, and with other applicable state laws; and 3. Conformance with the provision of using all known, available and reasonable methods to prevent and control pollution of state waters as required by RCW 90.48.010. WATER QUALITY CERTIFICATION CONDITIONS: Through issuance of this Order, Ecology ce1tifies that it has reasonable assurance that the activity as proposed and conditioned will be conducted in a manner that will meet the applicable water quality standw·ds and other appropriate 1-equirements of state law. In view of the foregoing and in accordance with 33 U.S.C. § 1341, RCW 90.48.120, RCW 90.48.260 Chapter 173-200 WAC and Chapter 173-20 lA WAC, water quality certificatiqn is granted to the Applicant subject to the conditions within this Order. · · Certification of this proposal does not authorize the Applicant to exceed applicable state water quality standards (Chapter l 73-201A WAC), ground water standards (Chapter 173-200 WAC) or sediment quality standards (Chapter 173-204 WAC). Furtherm01-e; nothing in this ce1tification shall absolve the Applicant from liability for contamination and any subsequent cleanup of surface waters, ground waters or sediments occuning as a result of project construction or operations. A. General Conditions: Order #9J5j, ..::~ips Refere11ce # NIVS-2010-158 King County /Valer and Land Resources Division Jam1ary 8, 2013 Page3 o/19 Al. For purposes of this Order, the tenn "Applicant" shall mean King County Water and Land Resources Division and its agents, assignees and contractors. A2. For purposes of this Order, all submittals required by its conditions shall be sent to Ecology's No1thwest Regional Office, Attn: 401/CZM Federal Project Manager, 3190 1601h Avenue SE, Bellevue, WA 98008-5452. Any submittals shall reference Order #9352 and Corps Reference #NWS-2010-158. A3. Work authorized by this Order is limited to the work described in the JARP A received by . Ecology cin June 20, 2012. The Applicant will be out of compliance with this Order and must reapply with an updated application if the information contained in the JARPA is voided by subsequent changes to the project not authorized by· this Order. A4. Within 30 days of receipt of an updated JARP A, Ecology will determine if the revised p1:oject requires a new water quality ce1iification and public notice or if a modification to this Order is required. AS. This Order shall be rescinded if the U.S. Army Corps of Engineers does not issue an individual Section 404 pe1mit. A6. Copies of this Order shall be kept on the job site and readily available for reference by Ecology personnel, the constrnction superintendent, construction managers-and lead workers, and state and local government inspectors. A 7. The Applicant shall provide access to the project site and all mitigation sites upon request by Ecology personnel for site inspections, monitoling, necessary data collection, and/or to ensure that conditions of this Order are being met. A8. .Nothing in this Order waives Ecology's authority to issue· additional ,orders if Ecology determines that futther actions are necessary to implement the water quality laws of the state. Further, Ecology retains continuing jurisdiction to make modifications hereto through supplemental order, if additional impacts due to project constmction or operation are identified (e.g., violations of water quality standards, downstream ernsion, etc.), or if additional conditions are necessary to further protect water quality. A9. The Applicant shall ensure that all appropriate project engineers and contractors at the project site have read and understand relevant conditions of this Order and all permits, approvals, and. documents·referenced in this Order. The Applicant shall provide Ecology a signed statement (see Attachment A for an example) from each project engineer and · contractor that they have read and understand the c.onditions of this Order and the above- Order #9352, ._.,1ps Reference# NWS-2010-158 King County Water and Land Resources Division Janua,,, 8, 2013 Page4 of19 referenced permits, plans, documents and approvals. These statements shall be provided to Ecology before construction begins at the project or n_utigation sites. AlO. This Order does not authorize direct, indirect, permanent, or temporary impacts to waters of the state or related aquatic resources, except as specifically provided for in conditions of this Order. · A 11. Failure of any person or entity to comply with this Order may result in the issuance of civil penalties or other actions, whether administrative or judicial, to enforce its terms. B. Wetland Compensatory Mitigation: B 1. · The Applicant shall mitigate wetland impacts as desc1·ibed in the May Creek Drainage Improvement Project (9Al 205)-King Co11n1y Water and Land Resources Division - Stream and Wetland Impact Analysis and Mitigalion Plan prepared by King County Road Services Division for King County Department of Natural Resources and Parks, dated Revised September 2011 and including the Long Marsh Creek Restoration Project- Basis of Design Report prepared by King County Water and Land Resources Division, dated September 14, 2011 (hereafter collectively called the "Mitigation Plan") or as modified by this Order or revised and approved by Ecology. B2. The Applicant shall submit any changes to the Mitigation Plan in writing to Ecology (see A2) for review and approval before work begins. B3. · The Applicant shall get review and written approval from Ecology of any plan changes , • required if problems arise during consttuction and planting of the wetland mitigation site. B4. The Applicant shall have a wetland professional at the wetland mitigation site during construction and planting. Implementation BS. Unless otherwise approved by Ecology in writing, the Applicant shall begin the compensatory mitigation project before, or concurrent with, impacting wetlands or Ecology may require additional compensation to account for additional temporal loss of wetland functions. B6. If the mitigation site(s) cannot be completed within 13 months of the date of this Order, the Applicant shall inform Ecology, in writing, of the status of a) May Creek Drainage Improvement Project, and b) May Creek and Long Marsh Creek restoration sites. With the: c) · Reason for the delay. d) Expected date of completion. O,·de,· #9352, <-'orps Refe,·e11ce # NWS-2010-158 King County Water a11d La11d Resources Divls/011 · Ja11Uary 8, 2013 Pages of19 The Applicant shall submit an updated written notification every 12 months thereafter until the May Creek Drainage hnprovement Project and May Creek and Long · Marsh Creek Restoration restoration sites are complete. B7. The Applicant shall ensure that all excess excavated site material is disposed ofin an appropriate location outside of wetlands and their buffers at the wetland mitigation site and above the 100-year floodplain. B8. The Applicant shall ensure that no material is stockpiled within existing wetlands and their buffers at the wetland mitigation site(s) at any time, unless provided for in the Ecology-approved Mitigation Plan. B9. The Applicant shall ensure that no construction debris is deposited within existing wetland and their buffers at the wetland mitigation site at any time, unless provided for in the Ecology approved Mitigation Plan. · Bl 0. The Applicant shall not use Polyacrylamide on exposed or disturbed soil at the mitigation site(s). B 11. The Applicant shall not use hay or straw on exposed or disturbed soil at the mitigation site(s). B 12. If seeding is used at the wetland mitigation site, the seed mix must contain native, annual, non-invasive plant species. B 13. The Applicant shall place signs at the mitigation areas' boundaries, including buffers, every 150 feet to mark the areas as wetland mitigation sites. B14. Upon completion of site-grading and prior to planting, the Applicant shall submit to Ecology written confirmation that the finished grades are consistent with the approved · Mitigation Plan or subsequent Ecology-approved plan changes. Written confirmation can be in the form of a signed letter from the surveyor or project engineer indicating how final elevations were confirmed and whether those elevations are consistent with the Mitigation Plan. B 15, Within 90 days of completing construction and planting of the mitigation site(s), the Applicant shall submit to Ecology (see A2) one hard copy and one electronic file of the final as-built report including maps. The as-built report must: a) Document site conditions at Year Zero. Order #9352, c.;orps Reference# NWS-2010-158 Ki11g Cou11ty Water and La11d Resources Divis/011 Janum)' 8, 2013 Page 60/19 b) Include the infomiation listed in Attachment B (Information Required for As-built Reports). c) Include documentation of the recorded legal meclianism required in Condition B16. Bl 6. Within 90 days of completing construction and planting of the May Creek and Long Marsh Creek restoration sites, the Applicant shall record a Wetlands Notice (see · Attachment C: Wetland Notice for Deed Notification). The Notice must be recorded with the County Recording Office, Registrar of Deeds, or other official responsible for maintaining records for, or interest in, real prope11y. This requirement·does not apply to that po1iion of the mitigation that is to occur within the Stonegate Open Space Tract. Monitoring and Maintenance B 17. The Applicant shall water and maintain all mitigation site planting~ so as to meet the Mitigation Plan's pe1fo1mance standards (Section 6). BIB. The Applicant shall monitor the mitigation site for a minimum of 10 years. The Applicant shall use the monitoring methods described on pages 27 and 28 of the Mitigation Plan (Section 6). B19. The Applicant shall submit to Ecology (see A2) one hard and one electronic copy of monitoring reports documenting mitigation site conditions for years 1, 2, 3, s, 7, and 10. At a minimum, the reports must contain the information in Attachment D (Information Required for Monitoring Reports). The Applicant shall submit the first monitoring repo1t 12 months after completing the mitigation site construction and planting. B20. The Applicant shall implement the Mitigation Plan's contingency measures if the Mitigation Plan's goals, objectives, or performance standards are not being met. B2 l. Prior to implementing contingency measures not specified in the Mitigation Plan, the Applicant shall consult with and obtain written approval from Ecology for the changes. B22. When necessary to meet the pe1fo1mance standards, the Applicant shall replace dead or dying plants with the same species, or an appropriate native plant alternative, during the first available planting season and note species, numbers, and approximate locations of all replacement plants in the subsequent monitoring report. B23. At the end of the monitoring period, the Applicant shall use the August 2004 or updated version of"Washington State Wetlands Rating System for Western Washington" to rate the wetland within the Stonegate Open Space Tract downstream ofthel48th Ave SE bridge and include the information in the monitoring repo1i. · Order #935;,, ..;orps Reference# NWS-2010-158 King C:ounty Water and Land Resources Dil'ision · January 8, 20 J 3 Page? o/19 B24. If the Applicant hllll not met all conditions and performance standards for the mitigation site at the end of the monitoring period, Ecology may require additional monitoring, additional mitigation, or both. B25. Until the Applicant has received written notice from Ecology that the Mitigation Plan has been fully implemented, the Applicant's obligation under Condition B 1 to mitigate for wetland impacts is not met. C. Water Quality Condition: Cl. May Creek is classified as "Sa!monid Spawning, Rearing, and Migration" and the criteria of that class apply except as specifically modified by this Order. This Order goes not authorize temporary exceedances of water quality sfondards beyond the limits established in WAC 173-20IA-200(1)(e)(i). C2. The Applicant shall implement the May Creek Drainage Improvement Project (9A 1205) Construct/on Water Q11ality Protection and 111onitoring Plan (hereafter called t.he "Water Quality Plan") prepared by King County Department of Natural Resources and Parks Water and Land Resources Division, revised September 7, 2011, or as modified by this Order or revised and approved by Ecology. C3. The Applicant shall submit any changes to the Water Quality Plan in writing to Ecology (see A2) for review and approval before work begins. n. Conditions fo1• Construction Activities: Gene1·al Conditions: D 1. Applicant shall comply with Construction Stormwater General Permit #WAR-124978 for this project. D2. Construction stormwater, sediment, and erosion control best management practices (BMPs; e.g., filter fences, etc.) suitable to prevent exceedances of state water quality standards shall be in place before starting construction at the site. D3. .Sediment and erosion control measures shall be inspected and maintained prior to and during project implementation. D4. All constrnction debris shall be properly disposed of on land so that it cannot enter a waterway or cause water quality degradation to state waters. Order #9352, ~JPS Reference #NWS-20/0-158 King County Water dnd Land Resources Division January 8, 2013 Page 8 o/19 D5. Machinezy and equipment .used during construction shall be serviced, fueled, and maintained upland, unless otherwise approved by Ecology, in order to prevent contamination to any surface water. D6. Wash water containing oils, grease, or other hazardous materials resulting from wash down of equipment or wotking areas shall be contained for proper disposal, and shall not be discharged into state waters or sto1m drains. D7. Clean Fill Criteria: Applicant shall ensure that fill (soil) placed for the proposed project does not contain toxic materials in toxic amounts. D8. Work in or near the water that may affect fish migration, spawning, or rearing shall cease immediately upon a dete1mination by Ecology that fisheries resources may be adversely ~ffected. D9. All manmade debris that has been deposited below the Ordinary High Water Line within ·· the construction work ru·ea shall be removed and disposed of upland such that it does not enter waters of the state. Cortcrete rubble, metal debris, and other debris in the construction work corridor that have washed into wetland and freshwater areas shall be removed from the project area. DlO .. In-water work shall be limited to activities required to bypass the creek, including fish exclusion and installation of cofferdams. The remainder of project activities shall occur. once the stream has been bypassed. DI 1. Sediment-laden water generated during constrnction shall be pumped to an infiltration or filtration site, or to a settling area, for subsequent .treatment prior to returning water to streams .. D12. Discharge of return water back to streams shall occw· in such a manner as to not cause erosion. D 13. Impacts to native vegetation shall be minimized to the extent practicable. D 14. In-stream willow removal shall be limited to the minimum amount required to restore flow conditions. D15. Removal of any willow branches and roots shall be conducted by hand or handheld small machinery in order to minimize disturbance. D16. In-water work shall be conducted during low-flow stream conditions. Order #935~ • ..:orps Reference# NWS-2010-158 King Cou11ty Water and Land Resources Divis/011 Janua,y 8, 2013 Page9o/19 Dl 7. .Construction equipment shall use existing farm access roads to cross the wetland and · access the stream, to the extent practicable. D 18. Equipment staging areas shall be located outside of stream and wetland buffers. D19. Streambed gravel stockpiles shall be located outside of stream and wetland buffers. D20. Low-impact tracked or rubber-tired construction equipment shall be used to minimize· disturbance to the wetland. D2 l. Machinery for removing sediment and reed canarygrass shall be operated from the bank. D22. Trucks utilized for transp01tation of sediments to temporary drying areas shall incorporate appropriate BMPs in order to prevent spillage of sediment-laden water into waters of the state. D23. Dredging shall be limited to deepening of the streambed. Banks shall not be disturbed. D24. Any excess material from construction shall be disposed of at an approved off-site disposal location. D25. Sediment disposal areas shall be stabilized using upland area erosion control seed mix. Prior to seed germination, a silt fence shall be installed and maintained around the . sediment disposal areas. E. Sediment Monitoring Conditions: El. The Applicant shall implement downstream post-construction erosion monitoring per the Memorandum from Bill Kerschke and Julia Turney, King County, to Don Althauser, King County, RE: May Creek Drainage Improvement Project (9Al205) Post-Construction Et·osion Monitoring Plan -Downstream of 14gth Avenue SE, dated August 4, 2011, including the May Creek Canyon Reach Draft Monitoring Plan: May_ Creek Sediment Transport Study Phase 4, prepared by Anchor QEA, LLC, dated December 2010, (jointly hereafter called the "Downstream Erosion Monitoring Plan), and any conditions of this Order. · E2. Any modifications or changes to the Downstream Erosion Monitoring Plan shall be submitted to Ecology for review and approval per Condition A2 within 30 days of submitting the annual report. ,, Order #9352, ,._,urps Refere11ce # NWS-2010-/ 58 King Cou11ty Water and La11d Resources Division Jam1a1J• 8, 2013 Page 10 o/19 E3. Monitoring shall occur for a minimum of five (5) years post-construction. Depending on the results of downstream post-construction erosion monitoring, additional monitoring may be required. E4. Downstream post-construction erosion monitoring repo1ts for Years 1-5 shall be submitted to Ecology per Condition A2 by February 1 of each year. ES. After each critical flood event, including the 1.0, 1.25, and 2-yeat· flood events, the Applicant shall monitor downstream locations per the Downstream Erosion Monitoring Plan for the presence or absence of bed hooks (eye bolts) or exposure of the bank pins (rebar). E6. The Applicant shall develop and utilize a downstream erosion monitoring form and provide training in the monitoring methods and use of the monitoring form to any monitors, including non-County staff, in order to ensure consistent data collection. The form shall include the date and time of observation and shall be utilized for 1.0, 1.25, and 2-year flood events. E7. If erosion is detected through the downstream monitoring, the Applicant shall revise the Downstream Erosion Monitoring Plan to include the following: a. Actions to be taken to address erosion impacts, including impacts on fish habitat. Erosion impacts will be considered to be impacts on fish habitat. b. Contingencies for any additional erosion. · F. Emergency/Contingency Measures: FI. The Applicant shall develop and implement a Spill Prevention and Containment Plan for all aspects of this project. F2. The Applicant shall have adequate and ·appropriate spill response materials on hand to respond to emergency release of petroleum products or any other material into waters of the state. F3. Fuel hoses, oil drums, oil or fuel transfer valves and fittings, etc., shall be checked regularly for drips or leaks, and shall be maintained and stored properly to prevent spills into state waters. F4. Any work that is out of compliance with the provisions of this Order, or conditions causing distressed or dying fish, or any discharge of oil, fuel, or chemicals into state waters, or onto land with a potential for entry into state waters, is prohibited. If these 9ccur, the Applicant shall immediately take the following actions: Order #935,, ,;o,ps Reference# NIVS-2010-158 King County IV ater a11d Land Resources Division January 8, 2013 Page 11 o/19 a. Cease operations at the location of the violation or spill. b. Assess the cause of the water quality problem and take appropriate measures to correct the prnblem and/or prevent further envirnnmental damage. c. Notify Ecology of the failure to comply. All oil spills shall be reported immediately to Ecology's 24-Hour Spill Response Team at 1-800-258-5990, and within 24 hours of spills or other events to Ecology's 401/CZM Federal Project Manager at (425) 649-· 7129 or (425) 649-7000. d. Submit a detailed written report to Ecology within five (5) days that describes the .nature of the event, con-ective action taken and/or planned, steps -to be taken to prevent a recurrence, results of any samples taken, and any other pertinent information . . Compliance with this condition does not relieve the Applicant from responsibility to maintain continuous compliance with the terms and conditions of this Order or the resulting liability from failure to comply. G. Timing Requirements G 1. All in-water work shall be completed by the work window identified· in the most cmTent Hydraulic Project Approval (HPA) issued for this project. Any prnject change that requires a new or revised ·HP A should also be sent to Ecology for review. · 02. This Order is valid until all compliance requirements in this document have been met. H. Reporting and Notification Requirement Conditions Hl. . The Applicant shall provide to Ecologis 401/CZM Federal Permit Manager a copy of the final Corps permit within 2 weeks of receipt of the permit. A copy shall be submitted per condition A2 above. H2. Applicant shall provide notice to Ecology's 401/CZM Federal Project Manager: o At least three (3) days prior to the start of each construction season. o Within 14 days after completion of construction for each season at the project site. Notification, referencing Corps Reference #NWS-2010-158, Order #9352 can take place by telephone to (425) 649-7129 or (425) 649-7000, fax to (425) 649-7098, or in wiiting. Order #9352, ...,orps Reference# NWS-2010-158 King County Water and Land Resow·ces DMs/on January 8, 2013 Page 12 o/19 H3. If the project construction is not completed within 13 months of issuance of this Order, the Applicant shall submit per Condition A2 a written construction status report and submit status reports every 12 months until construction and planting is complete. You have a right to appeal this Order to the Pollution Control Hearing Board (PCHB) within 30 days of the date of receipt of this Order. The appeal process is governed by Chapter 43 .2 lB RCW and Chapter 371-08 WAC. "Date of receipt" is defined in RCW 43.21B.001(2)._ To appeal you must do both of the following within 30 days of the date of receipt of this Order: · File your appeal and a copy of this Order with the PCHB (see addresses below). Filing means actual receipt by the PCHB during regular business hours. Serve a copy of your appeal and this Order on Ecology in paper form -by mail or in person. (See addresses below.) E-mail is not accepted. You must also comply with other applicable requirements in Chapter 43.21B RCW and Chapter 371-08 WAC. Department of Ecology Attn: Appeals Processing Desk 300 Desmond Drive SE Lacey, WA 98503 Pollution Control Hearings Board 1111 Israel Road SW STE301 ·Tumwater, WA 98501 Please direct all ·questions about this Order to: Rebekah Padgett Department of Ecology Northwest Regional Office 31901601h Avenue SE Bellevue, WA 98008 ( 425) 649-7129 rebekah.padgett@ecy.wa.gov Department of Ecology Attn: Appeals Processing Desk PO Box 47608 Olympia, WA 98504-7608 Pollution Control Hearings Board P0Box40903 Olympia, WA 98504-0903 Order #9352, ~o,ps Reference #NWS-2010-158 King County Water mid land Resources Division Ja11uary 8, 20 I 3 Page 13 o/19 Pollution Control Hearings Board Website www.eho.wa.gov/Boards PCHB.aspx Chapter 43.21B RCW -Environmental and Land Use Hearings Office -Pollution Control Hearings Board http://apps.leg.wa.gov/RCW /default.aspx?cite=4 3 .21 B Chapter 371-08 WAC -Practice And Proced11re http ://apps. leg. w~. gov /WAC/default. aspx?cite=3 71-08 Chapter 90.48 RCW -Water Pollution Control http://apps.leg.wa.gov/RCW/defau1t.aspx?cite=90.48 Chapter 173~204 WAC -Sediment Management Standards www.ecy.wa.gov/biblio/wac 173204.html Chapter 173-200 WAC-Water Quality Standards for Ground Waters of the State of Washington www.ecy.wa.gov/biblio/wacl 73200.html ' Chapter 173-201A WAC-Water Quality Standards for Surface Waters of the State of Washington www.ecy.wa.gov/biblio/wacl 73201 A.html Erik Stockdale, Unit Supervisor Wetlands/401 Unit Shorelands and Environmental Assistance Program Northwest Regional Office 1-<3-Wt?> January 8, 2013 Order #9352, _.,ps Refere11ce # NWS-2010-158 Kl11g Cou11ty Water a11d La11d Resources Divls/011 Jainta,Y 8, 2013 Page 14 o/19 ATTACHMENT A KING COUNTY WATER AND LAND RESOURCES DIVISION MAY CREEK DRAINAGE IMPROVEMENT PROJECT Water Quality Certification Order #9352 Statement of Understanding of Water Quality Certification Conditions · I have read and understand the conditions of Order #9352 Section 401 Water Quality Certification for the King County Water and Land Resources Division May Creek Drainage Improvement Project. I have also read and understand all permits, plans, documents, and approvals associated with the project referenced in this Order. Signature Date Title Company _; 01'der #935~. _o,ps Reference# NWS-2010-158 King County Water and Land Resources DMslon Jmiumy 8, 2013 Page 15 o/19 Attachment B Information for As-built Reports (See Condition B15) KING COUNTY WATER AND LAND RESOURCES DMSION MAY CREEK DRAINAGE IMPROVEMENT PROJECT Water Quality Certification Order #9352 Corps Reference #NWS-2010-158 Background Information 1) Project name. 2) Ecology docket number and the Corps reference number. 3) Name and contact information for the parties responsible for the mitigation site including: a) The applicant. b) The landowner. c) · Wetland professional on site during construction of the compensatory mitigation site. 4) Name and contact information for the party responsible for preparing the report. 5) Who the report was prepared for (name, address, and phone number) {if different.from mm1ber 3 above.} 6) Month and year the repo1t was produced. The Development Site 7) Brief description of the development project. Include: a) Directions to the site. · b) Month and year construction of the development project sta1ted and ended. c) Area (acres) and type(s) (rating category, HOM classification, and Cowardin classification) of wetlands that were actually impacted by the development project, including tempomry impacts. The Compensatory Mitigation Project 8) Brief description of the final compensatory mitigation project with any changes from the approved plan made during construction. Include: a) Directions to the site. b) Who completed the compensatory mitigation project (name, address, and phone· number. c) Acreage and type(s) (re-establishment, rehabilitation, creation, enhancement, and preservation) of mitigation authorized to compensate for wetland impacts. d) Important dates including: · i. Month and year the wetland impacts occurred. ii. When work on the compensatory mitigation site began and ended. Order 119352, ps Refere11ce f#NWS-2010-158 King Cou11ty Water and Land Resources Division JanUOIJ' 8, 2013 Page 16 o/19 iii. When different activities began and ended such as grading, removal of invasive plants, installing plants, and installing habitat features. 9) Description of any problems encountered and solutions implemented (with reasons for changes) during construction of the compensatory mitigation site. 10) Any changes to the goals, objectives, and pe1forn1ance standards of the compensatory mitigation project. 11) List of any follow-up actions needed, with a schedule. 12) Final site maps (8 1/2" x 11" or larger) of the compensatory mitigation site(s) including the following (at a minimum). a) Geographic location of the site with landmarks; b) Clear delineation of the project perimeter(s); c) Topography (with a description of how elevations were determined),; d) Installed planting scheme ( quantities, densities, sizes, and approximate locations of plants, as well as the SOUl'ce(s) of plant material); e) Location of habitat features; f) Location of permanent photo stations. The final site maps should reflect on-the-ground conditions after the site work is completed. Include the month and year when the maps were produced and, if applicable, when information was collected. · 13) Photographs of the site at as-built conditions taken from permanent photo stations. We recommend photo pans. 14) Copies of any records of deed notification or conservation easements. Order #93.5. :,rps Reference# NWS-20JO-i58 Ki11g Cou11/y Waler a11d Land Resources Divis/011 January 8, 2013 Page 17 o/19 Attachment C Wetlal\d Notice for Deed Notification (See Condition B16) KING COUNTY WATER AND LAND RESOURCES DIVISION MAY CREEK DRAINAGE IMPROVEMENT PROJECT Water Quality Certification Order #9352 Cor1>s Reference #NWS-2010-158 Tax Parcel Number: __________________________ _ Legal Description: __________________________ _ Legal Owner: ___________________________ _ NOTICE: This property contains wetlands as defined by Chapter 36.70A030(20) RCW, Chapter 90.58.030 (2)(11) RCW and WAC 173-201 A-020. The property was the subject of an Ecology action under Chapter 90.48.260 RCW or Chapter 90.48.120(1) RCW. --------------------.J issued on ______ __.20_ (Corps federal reference II) Ecology Docket # to'----,------,---------for __ ___,_----------~· (Applicant Name) (Project Name) Restrictions on use or alteration of the wetlands may exist due to natural conditions of the property and resulting regulations. A copy ofEcology's Order and the site map from the final wetland mitigation plan indicating the location of wetlands and their buffers is attached hereto. EXECUTED this ____ day of ______ __,20 __ State of Washington) County of __ __, I certify that I know.or have satisf:ilctory evidence that----------- . Signed this instrument and acknowledged it to be his/her free and voluntary act for the uses and purposes mentioned in this instrument. · GIVEN under my hand an official seal this ___ day of _____ .J20 __ NOTARY PUBLIC In and for the state of Washington, residing at .(Amended by Ord. 11200§ 50 (part), 1996) ,Order #9352, ps Reference #NWS-2010-158 King County Water a11d Land Resources Division January 8, 2013 Page 18 o/19 Attachment D Required Information for Monitoring Reports (See Condition B19) KING COUNTY WATER AND LAND RESOURCES DIVISION MAY CREEK DRAINAGE IMPROVEMENT PROJECT Water Quality Certification Order #9352 Corps Reference #NWS-2010-158 Ecology requixes the following infmmation, for monitoring reports submitted under this Order. Ecology will accept additional information that may be required by other regulators. Background Information 1) Project name · . 2) Ecology docket number and Corps refere11ce number 3) Name and contact infom1ation of the parties responsible for the mitigation site including:· a) The applicant b) The landowner 4) Name and contact infonnation for the party responsible for the monitoring activities and report 5) Who the repo1t was prepared for (name, address, and phone number) {if dif.ferentji·om number 3 above.} 6) Month and year the monitoring data were collected 7) Month and year the repmt was produced Mitigation Project Information 8) Brief description of the mitigation project including: a) Directions to the site b) Acreage and type(s) (re-establishment, rehabilitation, creation, e1iliancement, and preservation) of mitigation autho1ized to compensate for wetland impacts 9) Brief description of monitoring approach and methods. I 0) A list of the goals and objectives for the mitigation project 11) Sununruy table of monitoring data compared with perfonnance standards. Using the monitodng data, describe how the site is developing toward goals and objectives and whether the project is in compliance with performance standards · 12) SummEUy (including dates) of management actions (maintenance, contingencies, and corrective actions) implemented·at the site(s) 13) Summary of any difficulties or significant events that occurred on the site that may affect the ultimate success of the project Order #935. Jips Refere11ce # NWS-2010-158 King County Water d11d Land Resources Divis/011 Ja,mary 8, 2013 Page 19 o/19 14) Specific recommendations for any_additional corrective actions or adaptive management with a time table 15) Summary of any lessons learned 16) Site maps (8 1/2" x 11" or larger) of the compensatory mitigation site(s) including the following (at a minimum): a) The month and year when the maps were produced and, if applicable, when information was collected . b) The geographic location of the site with landmarks. c) Clear delineation of the project perimeter(s). d) Species, numbers, and approximate locations of all replanted material vegetation. e) Location of habitat features. f) Location of permanent photo stations and location of any other photos. g) Location of sampling points or transects. 17) Photographs taken at permanent photo stations ( and other photographs as needed) from the . most recent monitoring visit, which are dated and clearly indicate the direction from which the photo was taken. We recommend photo pans. KlngCounty Department of Perffllttlng and Environmental Review 35030 SE Douglas St., Ste. 210 Snoqualmie, WA 98065-9266 206-296·6600 TTY Relay 711 Clearing and Grading Permit type, Subtype: Grade, Grading TIiie: MAY CREEK DRAINAGE IMPROVEMENT Description: Removal of sediment on Mey Creek for In stream flow Improvements Location: Near SE May Valley Rd & 148th Ave. SE Permit Number. L10CG223 Date Issued: 11/14/2012 Expiration Date: 11/14/2013 Permit Status: Permit Issued List of Parcels: 0223059005, 0223059075, 0223059076, 0223059084, 0223059091 Site Address: Valuation: $0.00 Applicant Name: KING COUNTY WLRD ·- Applicant Address: ATTN DOUG CHIN 201 S JACKSON ST SUITE 600 MS: KSC-NR-0600 SEATTLE, WA 98104 Owner Name: Owner Address: Please refer to the above project number when making inquiries regarding this application. For Permit Information. or requests for Inspections, call your Grading/Clearing Inspector at 1-888-546-7728. CERTIFICATION I certify under penalty of perjury under the laws of the Stele of Washington that the Information furnished by the owner or owner's agent In support of this application is true and correct. I further certify that all applicable King County requirements for the work authorized by this permit, If Issued, will be met and that violation thereof will be cause for code enforcement action. I have read the attached conditions of approval and understand that failure to comply with ell conditions set forth herein shall necessitate an Immediate work stoppage until such time es compliance with the stipulated conditions is attained . Failure to comply or repeated violattons of permit conditions may result on enforcement actions, civil penatties as authorized under K.C.C. Tille 23, and/or permit suspension or revocation. The granting of this permit shall not be construed as saUsfying the requirements of other applicable Federal, State or Local government permits or regulations . The operaUon and maintenance of facilities authorized under this permit shall be conducted In accordance with the Owner /Applicant Signature Tille Date EXHIBIT 26 eaf-all-0028 printed: 11/14/2012 Page 1 of 2 ~ King County Department of Permitting and Environmental Review 35030 SE Douglas St., Ste. 210 Snoqualmie, WA 9806S-9266 206-296-6600 TTY Relay. 711 Permit: L 1 OCG223 Inspection Report Card Record Card must be on the Job site EROSION CONTROL DEVICES SHALL BE IN PLACE PRIOR TO AND DURING CONSTRUCTION ' APPROVALS: 1. Preconstruction Conference By: ------- 2. Erosion Control (installed and functioning) By: ------- 3. Limits of Clearing per Approved Plans By: --~---- 4. Construction Entrance installed per Plans By: ------- 5. Site Stabilization and Soil Amendments Installed By: ------- 6. Final-Site Re-vegetated and all Facilities Functioning p By: ----~-- 7. Other By: -------8. Other · By: ------- Notes ALL PERMITS: a) Responsibility for the building's compliance with the provisions of the applicable King County Codes and for maintenance of the building rests exclusively with the permit applicants and their agents and the property owners. b) King County inspection of the building and real property are spot checks designed to foster and encourage compliance with the applicable codes. Neither the approvals above not the issuance of a Certificant of Occupancy guarantees or assures compliance with all applicable codes. aaf-eU-0026 printed: 11/14/2012 Page2of2 Conditions of Approval Grading Permit No. LlOCG223 May Creek Drainage Improvements 5010 -At least 48 hours prior to the start of any work, call the Site Development Services Section at 206-296-6781 to arrange a preconstruction meeting. Be advised this permit shall not be effective until the notice to proceed has been issued pursuant to this meeting. 5011 -No construction under this permit shall take place until all other federal, state, and local permits have been obtained and are current with operating conditions and dates. Prior to commencement of construction under this permit the permittee shall provide copies of these issued project permits/approvals to DOES. 5015 -The boundaries of the clearing limits shown on this plan shall be clearly flagged in the field prior to construction. No clearing or other site work shall take place until these limits are approved in the field by ODES staff. During the construction period, no disturbance beyond the flagged clearing limits shall be permitted. The flagging shall be maintained by the permitted for the duration of the project. 5035 -Work shall be limited to that shown on the approved site plans dated 09/20/2012. A copy of the approved plans, conditions, and permit must be on the job site whenever work is in progress. 5045 -All land clearing debris to be removed from the site shall be disposed of or recycled in an approved, legal disposal or recycling site. It shall be the permittee's responsibility to locate acceptable disposal or recycling sites and to assure that all land clearing debris is disposed in those sites. 5046 -All surplus excavated sand, gravel, and other earthen materials to be removed from this site shall be disposed of in a legal manner, and to a legal permitted receiving site. It shall be the permittee's responsibility under this permit to track and account for offsite disposal activities of earthen materials associated with this permit. 5048 -The permittee shall comply with local fire district rules and regulations regarding debris burning, fire prevention, and fire suppression. 5050-All work shall comply with the provisions of King County Ordinance 3139, relating to noise control. 5055 -A Hydraulic Project Approval (HPA) is required for this project. Contact the Washington State Department of Fish and Wildlife at 425-775-1311 for more information. Conditions of Approval Grading Permit No. L!OCG223 Page 2 5060-Hours of operation shall be limited to 7:00am to 7:00pm, Monday through Saturday, and 1 O:OOarn to 5:00pm on Sundays. Hours of operation may be further restricted during peak traffic hours. 5070 -Permittee shall abide by the regulations of the Puget Sound Clean Air Agency (PSCAA). 5085 -You must call 1-800-424-5555 not less than 48 hours before beginning any site work where underground utilities may be located. Failure to do so could result in bearing substantial repair costs (up to three times the cost of repairs to the service). 5390 -The erosion and sedimentation control measures required for this permit are intended to be minimum requirements to meet anticipated site conditions. As work progresses and unexpected or seasonal conditions dictate, the permitted should anticipate that more siltation and sedimentation control facilities will be necessary to ensure complete silta- tion control on the proposed site. During the course of construction, it shall be the obligation and responsibility of the permitted to address any new conditions that may be created by site activities and to provide additional erosion sedimentation control measures. 5460 -Permitted shall be responsible for implementing all appropriate measures needed (i.e. paving, sweepers,.and/or other techniques) to keep streets and roads used as haul routes, clean and free from debris, dirt, and mud. 54 70 -Any damage to pavement edges, sidewalk, curb and gutter, etc., resulting from operations authorized by this permit shall be repaired immediately. 5500 -During the time period of October 1, through April 30, all disturoed areas that are to be left unworked for more than 2 days shall be covered by one of the following cover measures: straw mulch, erosion control blankets or netting, plastic covering, or sodding. This requirement shall also apply during the time period of May 1, through September 30, for all disturbed areas left unworked for more than 7 days. Cover measures shall comply with standards outlined in appendix "D" of the King County Surface Water Design Manual. Where straw mulch is used for site covering, a minimum 2 inch thickness shall be applied. 5505 -Clearing and erosion. control measures for this site shall comply with section D.5.2- Wet Season Requirements -of Appendix D, of the 2009 King County Surface Water . Design Manual for any work performed during the wet season (October 1, through April 30). Conditions of Approval Grading Permit No. LlOCG223 Page 3 551 O -All project disturbed areas where site disturbance has occurred exposing mineral soil, shall be permanently seeded per standards outlined in section D.4.2.4 of the King County Surface Water Design Manual. 5520 -Filter fabric fence (silt fence) shall be used around the perimeter of the site, where necessary, to insure that sediment laden water does not leave the site. Filter fabric fence shall be install.ed and maintained per detail D.4.E-appendix D of the King County Surface Water Design Manual. 5522 -Work authorized by this permit shall be limited to tax parcel numbers 022305-9076, -9091, -9075, -9084, -9005, & 803540TR-A only. 5650 -A National Pollutant Discharge Elimination System (NPDES) permit for surface water discharge may be required for this project. Contact the Washington State Dept. of Ecology at (360) 649-7000 for information. 5700 -All subsequent site inspections required by this permit shall be billed at the applicable hourly rate as authorized by King County Code. 5800-Critical Areas Conditions: By this reference, the conditions contained in the memo dated September 13, 2012, as revised November 6, 2012 from Nick Gillen, Environmental Scientist III, are hereby adopted as additional conditions of approval for this permit. A copy of these conditions are attached to this permit. 5810 -Flood Hazard Review Conditions: By this reference, the conditions contained in the memo dated September 6, 2012 from Don Gauthier, Engineer III, are hereby adopted as additional conditions of approval for this permit relating specifically to disposal of earthen Dredging's outside of the 100 year floodplain, and storage/ staging of materials and equipment within the 100 year floodplain from September 30, to May l. A copy of this memo is attached to this permit. 5820 -The project representative shall monitor all grading and excavation to confirm that the work meets both design specifications of the approved engineering plans and remains consistent with the conveyance capacity improvements specified by the hydrologist. Written correspondence verifying compliance to the approved plans and the hydrologist's recommendations shall be presented to the project representative in the form of record drawings. Field measurements may be requested by the permit agency(s) to King County for confirmation of compliance following completion of excavation prior to advancing to other properties. Conditions of Approval Grading Permit No. L!OCG223 Page4 5900 -No construction under this permit shall take place until all other federal, state, and local permits have been obtained and are current with operating conditions and dates. These permits may include but not limited to: Hydraulic Project Approval (HPA), Section 401 Water Quality Certification, Section 404 Permit, Storm Water NPDES; Prior to construction under this permit, the permittee shall provide copies of these issued project permits/approvals to ODES. Conditions of Approval Grading Pennit No. L10CG223 Critical Ateas Conditions of Approval Page 5 September 13, 2012 Revised November 6, 2012 TO: Jon Pederson, Site Development Specialist FM: Nick Gillen, Environmental Scientist ill RE: May Creek Drainage Improvement Project, LlOCG223, Critical Area Conditions of Approval Staff has reviewed the submitted material for the above referenced file. Staff concurs that the projects meets the criteria as listed under 21A.24.045 (D-61), Allowed Alterations (Flood Risk Reduction Gravel Removal). The following conditions shall apply to this permit. 1. All work within the aquatic area and wetlands should be completed during summer low water periods typically from mid May to mid September. Any work done outside to this window may require special erosion control measures and/or a biologist on-site during working hours. 2. All areas of disturbance shall be replanted with native vegetation within 3 months of completing construction activities. 3. The Long Marsh Creek Restoration Project is an important part of the May Creek Drainage project for controlling sediment in May Creek. Upon completion the restoration project it shall be monitored along with the May Creek project to determine if the goals and objectives as stated in the report have been or are being met. 4. The May Creek Mitigation plan, within the City of Renton, shall be implemented within 3 months of project completion. This out of county mitigation is subject to permits from the City. No work within King County may start without first obtaining the City permits or permission. If City permits cannot be obtained then an alternative mitigation plan will need to be submitted, reviewed and approved prior to any work within King County. 5. Monitoring reports shall need to be submitted to DPER once a year for five years after mitigation implementation. " ... -~ RECEIVED MAR 1 5 2011 K.C. Roads Engineering Services NMFS Tracking Number: 2011/0060! Erick Thompson Road Services Division Department of Transportation KSC-TR-0231 201 S. Jackson Street Seattle, Washlngton 98104-3856 UNITED STATES DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration NATIONAL MARINE FISHERIES SERVICE Northwest Region 7600 Sand Point Way N.E., Bldg. l Seattle, Washington 98115 March 10, 2011 . Re: Endangered Species Act Section 7 Informal Consultation and Magnuson-Stevens Fishery Conservation and Management Act Essential Fish Habitat Consultation for King County for the May Creek Drainage Improvement Project (Sixth-field Hydrologic Unit Code 171100120400, Lake Washington-Sammamish River). Dear Mr. Thompson: This correspondence is in response to your request for informal consultation under the Endangered Species Act (ESA) of 1973, as amended, 16 U.S.C. 1531. The National Marine Fisheries Service (NMFS) has reviewed the Biological Assessment (BA) for the above referenced proposal, received on February 25, 2011. King County (County) requested concurrence with its determination that the proposed action "may affect, but is not likely to adversely affect" the threatened Puget Sound (PS) Chlnook salmon (Oncorhynchus tshawytscha) (70 FR 37160), and the threatened PS Steelhead (0. mykiss) (72 FR 26722). This consultation with the County is conducted under section 7(a)(2) of the ESA, and its implementing regulations, 50 CFR Part 402. There is no critical habitat in the action area The County is proposing to improve in-stream flow conditions between approximately river mile (RM) 4.3 and 4.9 of May Creek. Sediment accumulation and in-stream vegetation have been gradually decreasing channel flow capacity, causing a backwater effect and increasing flood duration on pastures. The project includes vegetation and sediment removal, along with stream and wetland mitigation. Invasive reed canary grass and sediment will be removed from the channel with macmnery, most likely a trackhoe operated from the bank. The stream will be diverted around the work site, and erosion and sediment control best management practices will be implemented. In addition, willows that are obstructing flow would be removed by hand or with hand-held machlnery. Approximately 4,050 cubic yards of material will be removed from the stream channel. EXHIBIT 27 • 2 As mitigation for these actions, the County will enhance about two acres of wetland and riparian habitat by suppressing invasive vegetation and replanting with native vegetation. Fencing will be installed around the planting areas to minimize livestock access to the stream. In-stream mitigation activities will also occur at two locations. At the first site on May Creek, the County will excavate off-channel alcoves, and enhance them with large woody debris and native vegetation. At the second site, the County will create meanders and plant native vegetation along 300 feet of Long Marsh Creek at the confluence with May Creek. A 100-foot long side channel will also be created at this site. These mitigation activities will increase habitat complexity and overwintering habitat, and increase sediment retention capabilities, reducing sediment transport to downstream reaches. The in-water work window will be August 1 through 31. In-water work will be limited to activities required to bypass the creek, including fish exclusion and installation of cofferdams. The action area will extend for 300 feet downstream of the downstream-most in-water work (i.e. to RM 4.2) to account for increased suspended sediment concentrations. In general, this type of project could affect ESA listed salmonids by increasing the amount of suspended sediments in the stream, by injuring fish with equipment, or by displacing fish from the project site. In addition, removal of vegetation from the riparian zone and stream channel could potentially affect shade, cover, and allochthonous input. Species Determination Neither PS Chinook salmon or PS steelhead have been documented within about 0. 75 miles of the project action area. Thus, potential direct effects, including injury and displacement from equipment and in-stream work, will be discountable. The County will divert flows around the work site, helping to decrease the amount of suspended sediments drifting downstream. Also, suspended sediment concentrations will dissipate before reaching PS Chinook salmon or steelhead habitat, so potential effects will be insignificant. Potential reductions in shade, cover, and allochthonous input will have insignificant effects due to distance of the action area from PS Chinook salmon and steelhead habitat. The NMFS concurs with the County's determination that the project "may affect, but is not likely to adversely affect" PS Chinook salmon and PS steelhead. This concludes informal consultation on these actions in accordance with 50 CFR 402.14(b)(l). The County must reinitiate the ESA consultation if: (1) new information reveals effects of the actions that may affect listed species in a way not previously considered; (2) the actions are modified in a manner that causes an effect on the listed species that was not previously considered; or (3) a new species is listed, or critical habitat is designated, that may be affected by the proposed actions. ' . 3 Magnuson-Stevens Fishery Conservation and Management Act Federal agencies are required, under section 305(b)(2) of the MSA and its implementing regulations (50 CFR 600 Subpart K), to consult with NOAA Fisheries regarding actions that are authorized, funded, or undertaken by that agency that may adversely affect Essential Fish Habitat (EFH). The MSA section 3 defines EFH as "those waters and substrate necessary to fish for spawning, breeding, feeding, or growth to maturity". !fan action would adversely affect EFH, NMFS is required to provide the Federal action agency with EFH conservation recommendations (MSA section 305(b)(4)(A)). This consultation is based, in part, on information provided by the Federal action agency and descriptions ofEFH for Pacific salmon contained in Appendix A to Amendment 14 to the Pacific Coast Salmon Plan (August 1999) developed by the Pacific Fishery Management Council and approved by the Secretary of Commerce (September 27, 2000). The proposed action and action area are described in this letter and in the BA. The action area includes habitat that has been designated as EFH for various life stages of Chinook and coho ( 0. kisutch) salmon. · EFH Conservation Recommendations: Because the conservation measures that the County included as part of the proposed action to address ESA concerns are also adequate to avoid, minimize, or otherwise offset potential adverse impacts to the EFH of the species listed · above, conservation recommendations pursuant to MSA (section 305(b)(4)(A)) are not necessary. Since NMFS is not providing conservation recommendations at this time, no 30- day response from the County is required (MSA section 305(b)(4)(B)). This concludes consultation under the MSA. If the proposed action is modified in a manner that may adversely affect EFH, or if new information becomes available that affects the basis for NMFS' EFH conservation recommendations, the County will need to reinitiate EFH consultation with NMFS in accordance with implementing regulations for EFH at 50 CFR . . 600.920(k). The NMFS appreciates your efforts to comply with requirements under the ESA and MSA. If you have questions, please contact Jody Walters at the Washington State Habitat Office, (360) 534-9307, or email Jody.Walters@noaa.gov. cc: Lori Lull, COE Sincerely, L; William W \) Regional A :. .\ i . Washington Department of 1 FISH and WILDLIFE HYDr-\ULIC PROJECT APPROVAi -! RCW 77.55.021 -See appeal process at end of HPA Issue Date: September 26, 2011 Control Number: Project Expiration Date: August 10, 2016 FPNPublic Notice#: North Puget Sound 16018 Mm Creek Boulevard Mill Creek, WA 98012-1296 (425) 775-1311 123184-2 NIA PERMITIEE AUTHORIZED AGENT OR CONTRACTOR King County Water and Land Resources Division ATIENTION: Doug Chin 201 S Jackson St Ste 600 Seattle, WA 98104 206-296-8315 Fax: 206-296-0192 Project Name: May Creek Drainage Improvement Project (9A1205) Project Description: Improve in-stream flow conditions along segments of May Creek in May Valley between approximately River Mile 4.3 and 4.9. Remove vegetation and instream debris which is impeding flows and dredge 4,050 cubic yards of sediment from May Creek. Stream and wetland mitigation consists of: 1. Enhancing a 15 foot wide buffer of vegetation on each side of May Creek. 2. Installation of off-channel alcoves adjacent to May Creek downstream of 148th Ave. SE. 3. Restoration at the lower end of Long Marsh Creek. PROVISIONS 1. The project may begin immediately and shall be completed by August 10, 2016, provided work below the ordinary high water line (OHWL) shall occur only between June 16 and September 15. 2. NOTIFICATION REQUIREMENT: The Area Habitat Biologist (AHB) listed below (e-mail to fisheldf@dfw.wa.gov) and the Enforcement Program Officer (e-mail to capeljlc.@dfw.wa.gov) shall receive e-mail notification from the person to whom this HPA is issued (permittee) no less than three working days prior to start of work, and again within seven days of completion of work to arrange a compliance inspection. The notification shall include the permittee's name, project location, starting date of work or completion date of work, and the control number of this HPA. 3. Work shall be accomplished per plans and specifications approved by the Washington r Department of Fish and Wildlife (WDFW) entitled, "MAY CREEK DRAINAGE IMPROVEMENT", dated September 15, 2011; "LONG MARSH CREEK RESTORATION", dated July 18, 2011; an< "May Creek Drainage Improvement Project (9Q1205) King County Water and Land Resources 1 Division Stream and Wetland Impact Analysys and Mitigation Plan", dated revised September I 2011, except as modified by this HPA. A copy of these plans shall be available on site during construction. 4. Installation of project mitigation components are required to compensate for impacts of the project on fish life and shall be overseen by a qualified stream ecologist. 5. A temporary bypass to divert flow around the work area shall be in place prior to initiation of i . ' nthP.r wnrk within thP. wP.ttP.rl nP.rimP.tP.r. Washington Department of FISH and WILDLIFE HYDr · 'JLIC PROJECT APPROVAL RCW 77.55.ul1 -See appeal process at end of HPA Issue Date: September 26, 2011 Control Number: Project Expiration Date: August 10, 2016 FPA/Public Notice#: North Puget Sound 16018 Mill Creek Boulevard Mill Creek, WA 98012-1296 (425) 775-1311 123184-2 N/A 6. A sandbag revetment or similar device shall be installed at the bypass inlet to divert the entire flow through the bypass. 7. A sandbag revetment or similar device shall be installed at the downstream end of the bypass to prevent backwater from entering the work area. 8. The bypass shall be of sufficient size to pass all flows and debris for the duration of the project. 9. Prior to releasing the water flow to the project area, all instream work shall be completed. 10. Upon completion of the project, all material used in the temporary bypass shall be removed from the site and the site returned to preproject or improved conditions. 11. The permittee shall capture and safely move food fish, game fish, and other fish life from the job site. The permittee shall have fish capture and transportation equipment ready and on the job site. Captured fish shall be immediately and safely transferred to free-flowing water downstream of the project site. The permittee may request that WDFW assist in capturing and safely moving fish life from the job site to free-flowing water, and assistance may be granted if personnel are available. · 12. Any device used for diverting water from a fish-bearing stream shall be equipped with a fish guard to prevent passage of fish into the diversion device pursuant to RCW 77.57.010 and 77.57.070. The pump intake shall be screened with 1/8-inch mesh to prevent fish from entering the system. The screened intake shall consist of a facility with enough surface area to ensure that the velocity through the screen is less than 0.4 feet per second. Screen maintenance shall be adequate to prevent injury or entrapment to juvenile fish and the screen shall remain in place whenever water is withdrawn from the stream through the pump intake. 13. Dredging shall be accomplished by starting at the upstream end of the project boundary and working downstream. 14. Dredging shall be limited to deepening of the streambed. Banks shall not be disturbed. 15. Upon completion of the dredging, the streambed shall be contoured with pools and riffles similar to its configuration prior to the dredging. 16. Salmonid spawning habitat at the confluence of Long Marsh Creek with May Creek shall not be impacted. There shall be a minimum of 18 inches deep spawning gravels there upon completion of dredging. 17. Materials placed at the outlet of the culvert on Long Marsh Creek shall consist of rounded boulders, cobbles, and gravel, rather than the riprap shown on page 4 of the plans for Long Marsh Creek. -~ Washington Department of FISH and · WILDLIFE HYr-\ULIC PROJECT APPROVA' ' RCW 77 .5ti.021 -See appeal process at end of HPA Issue Date: September 26, 2011 Control Number: Project Expiration Date: August 10, 2016 FPA/Public Notice #: North Puget Sound 16018 Mill Creek Boulevard Mill Creek, WA 98012-1296 (425) 775-1311 123184-2 N/A 18. Fish habitat components as shown in the approved plans (Provision 3) are required as part of the project to mitigate project impacts. Large woody material installed as fish habitat components shall be coniferous and shall be installed in a manner sufficiently far from the bank to provide fully functioning fish habitat and shall be securely anchored to withstand 100-year peak flows using buried anchors and heavy duty chain or sufficient rock ballast. 19. Disturbance of the streambed and banks and their associated vegetation shall be limited to that necessary to perform the project. Affected streambed and bank areas shall be restored to preproject or improved habitat configuration. Prior to December 31 of the year of project grading, the approved planting plan (Provision 3) shall be installed. Project performance standards, monitoring, maintenance, and contingencies shall occur as described in this plan on pages 27-28. 20. Equipment used for this project shall be free of external petroleum-based products while working around the stream and wetlands associated with the stream. Accumulation of soils or debris shall be removed from the drive mechanisms (wheels, tires, tracks, etc.) and undercarriage of equipment prior to its working below the OHWL. Equipment shall be checked daily for leaks and any necessary repairs shall be completed prior to commencing work activities along the stream and wetlands associated with the stream. 21. If at any time, as a result of project activities, fish are observed in distress, a fish kill occurs, or water quality problems develop (including equipment leaks or spills), immediate notification shall be made to the Washington Emergency Management Division at 1-800-258-5990, and to the AHB. 22. Erosion control methods shall be used to prevent silt-laden water from entering the stream and wetlands associated with the stream. These may include, but are not limited to, straw bales, filter fabric, temporary sediment ponds, check dams of pea gravel-filled burlap bags or other material, and/or immediate mulching of exposed areas. 23. Prior to starting work, the selected erosion control methods (Provision 22) shall be installed. Accumulated sediments shall be removed during the project and prior to removing the erosion control methods after completion of work. 24. Wastewater from project activities and water removed from within the work area shall be routed to an area landward of the OHWL to allow removal of fine sediment and other contaminants prior to being discharged to the stream or wetlands associated with the stream. 25. All waste material such as construction debris, silt, excess dirt or overburden resulting from this project shall be deposited above the limits of floodwater in an approved upland disposal site. 26. If high flow conditions that may cause siltation are encountered during this project, work shall stop until the flow subsides. HYor. 'ILIC PROJECT APPROVAL .-....., \ North Puget Sound 16018 Mill Creek Boulevard Mill Creek, WA 98012-1296 (425) 775-1311 RCW 77.55.021 -See appeal process at end of HPA Issue Date: September 26, 2011 Project Expiration Date: August 10, 2016 Control Number: FPA/Public Notice#: 123184-2 NIA 27. Extreme care shall be taken to ensure that no petroleum products, hydraulic fluid, fresh cement, sediments, sediment-laden water, chemicals, or any other toxic or deleterious materials are allowed to enter or leach into the stream or wetlands associated with the stream. NOTE This HPA is a modification of and supercedes the original HPA issued August 11, 2011 for this project. The modification pertains to updated plans referenced in Provision 3. PROJECT LOCATIONS Location #1 May Creek rm 4.3 to 4.9 WORK START: September 26, 2011 IWORKEND: August10,2016 WRIA: --Waterbody: Tributary to: 08.0282 May Creek Lake Washington 1/4 SEC: Section: Township: Range: Latitude: Longitude: County: ---- NW 1/4 02 23 N 05 E N 47.51149 W 122.13461 King Location #1 Driving Directions Location #2 May Creek rm 4.3 to 4.9 WORK START: September 26, 2011 JWORKEND: August10,2016 WRIA: --Waterbody: Tributary to: 08.0282 May Creek Lake Washington 1/4 SEC: Section: Township: Range: Latitude: Longitude: County: ---- NE 1/4 03 23 N 05 E N 47.51599 W 122.14429 King Location #2 Driving Directions APPLY TO ALL HYDRAULIC PROJECT APPROVALS This Hydraulic Project Approval pertains only to those requirements of the Washington State Hydraulic Code, specifically Chapter 77.55 RCW (formerly RCW 77.20). Additional authorization from other public agencies may be necessary for this project. The person(s) to whom this Hydraulic Project Approval is issued is responsible for applying for and obtaining any additional authorization from other public agencies (local, state and/or federal) that may be necessary for this project. This Hydraulic Project Approval shall be available on the job site at all times and all its provisions followed by the person(s) to whom this Hydraulic Project Approval is issued and operator(s) performing the work. ... Washington Department of FISH and WILDLIFE HYr \ULIC PROJECT APPROV.A' RCW 77.55.021 -See appeal process at end of HPA Issue Date: September 26, 2011 Control Number: Project Expiration Date: August 10, 2016 FPNPublic Notice#: This Hydraulic Project Approval does not authorize trespass. North Puget Sound 16018 Mill Creek Boulevard Mill Creek, WA 98012-1296 (425) 775-1311 123184-2 N/A The person(s) to whom this Hydraulic Project Approval is issued and operator(s) performing the work may be held liable for any loss or damage to fish life or fish habitat that results from failure to comply with the provisions of this · Hydraulic Project Approval. Failure to comply with the provisions of this Hydraulic Project Approval could result in a civil penalty of up to one hundred dollars per day and/or a gross misdemeanor charge, possibly punishable by fine and/or imprisonment. All Hydraulic Project Approvals issued under RCW 77.55.021 are subject to additional restrictions, conditions, or revocation if the Department of Fish and Wildlife determines that changed conditions require such action. The person(s) to whom this Hydraulic Project Approval is issued has the right to appeal those decisions. Procedures for filing appeals are listed below. Requests for any change to an unexpired HPA must be made in writing. Requests for new HPAs must be made by submitting a new complete application. Send your requests to the department by: mail to the Washington Department of Fish and Wildlife, Habitat Program, 600 Capitol Way North, Olympia, Washington 98501-1091; e-mail to HPAapplications@dfw.wa.gov; fax to (360) 902-2946; or hand-delivery to the Natural Resources Building, 1111 Washington St SE, Habitat Program, Fifth floor. APPEALS INFORMATION If you wish to appeal the issuance, denial, conditioning, or modification of a Hydraulic Project Approval (HPA), Washington Department of Fish and Wildlife (WDFW) recommends that you first contact the department employee who issued or denied the HPA to discuss your concerns. Such a discussion may resolve your concerns without the need for further appeal action. If you proceed with an appeal, you may request an informal or formal appeal. WDFW encourages you to take advantage of the informal appeal process before initiating a formal appeal. The informal appeal process includes a review by department management of the ·HPA or denial and often resolves issues faster and with less legal complexity than the formal appeal process. If the informal appeal process does not resolve your concerns, you may advance your appeal to the formal process. You may contact the HPA Appeals Coordinator at (360) 902-2534 for more information. · A. INFORMAL APPEALS: WAC 220-110-340 is the rule describing how to request an informal appeal of WDFW actions taken under Chapter 77 .55 RCW. Please refer to that rule for complete informal appeal procedures. The following information summarizes that rule. A person who is aggrieved by the issuance, denial, conditioning, or modification of an HPA may request an informal appeal of that action. You must send your request to WDFW by mail to the Washington Department of Fish and Wildlife HPA Appeals Coordinator, 600 Capitol Way North, Olympia, Washington 98501-1091; e-mail to HPAapplications@dfw.wa.gov; fax to (360) 902-2946; or hand-delivery to the Natural Resources Building, 1111 Washington St SE, Habitat Program, Fifth floor. WDFW must receive your request within 30 days from the date you receive notice of the decision. If you agree, ani:t you applied for the HPA, resolution of the appeal may be facilitated through an informal conference with the WDFW employee responsible for the decision and a supervisor. If a resolution is not reached through the informal conference, or you are not the person who applied for the HPA, the HPA Appeals Coordinator cir designee will conduct an informal hearing and recommend a decision to the Director or designee. If you are not satisfied with the results of the informal appeal, you may file a request for a formal appeal. B. FORMAL APPEALS: WAC 220-110-350 is the rule describing how to request a formal appeal of WDFW actions taken under Chapter 77.55 RCW. Please refer to that rule for complete formal appeal procedures. The following information summarizes that rule. > Washington Department of · FISH and X;" WILDLIFE HYO~ . 'JLIC PROJECT APPROVAi RCW 77.55.021 -See appeal process at end of HPA Issue Date: September 26, 2011 Control Number: Project Expiration Date: August 10, 2016 FPA/Public Notice#: North Puget Sound 16018 Mill Creek Boulevard Mill Creek, WA 98012-1296 (425) 775-1311 123184-2 N/A A person who is aggrieved by the issuance, denial, conditioning, or modification of an HPA may request a formal appeal of that action. You must send your request for a formal appeal to the clerk of the Pollution Control Hearings Boards and serve a copy on WDFW within 30 days from the date you receive notice of the decision. You may serve WDFW by mail to the Washington Department of Fish and Wildlife HPA Appeals Coordinator, 600 Capitol Way North, Olympia, Washington 98501-1091; e-mail to HPAapplications@dfw.wa.gov; fax to (360) 902-2946; or hand-delivery to the Natural Resources Building, 1111 Washington St SE, Habitat Program, Fifth floor. The lime period for requesting a formal appeal is suspended during consideration of a timely informal appeal. If there has been an informal appeal, you may request a formal appeal within 30 days from the date you receive the Director's or designee's written decision in response to the informal appeal. C. FAILURE TO APPEAL WITHIN THE REQUIRED TIME PERIODS: If there is no timely request for an appeal, the WDFW action shall be final and unappealable. ENFORCEMENT: Sergeant Chandler (34) P1 E Habitat Biologist Larry Fisher CC: 425-313-5683 for Director WDFW ~ I ' ' m X :::c 1-"'4 C',7 000M 01-201 1-1 : coumY 01-2010 -I l COl.tm' ~-2010 :AAT, PI.S o::t-2010 N ""' \I) L ,_ / 1J ' .• ' ~ ' • • ',,, ~.c.,_ '-I . .. ' ..,}-,,, ' 1 .. . .. ' ', .... l ............ ,. l/\· • .. ', ~, ' BUfFER {25') ••• c, ~ •• \ •+ '\ I '- Wl'IC,l,,TION Pl.AN H0TtS CONSrRUC'TION N01'tS 1. TREES TO II[ PffESEll'.'CD 'MU. BE FlACCm IN tHt fla.D BY TiiE ECOI..OGIST. wrn»<O •• • \ d ' ·---•, . ' . .. ' . ,. . .. ' ', ·---.,.,·-..,...J ~.;( \ ~ ... -I l '' gr ~"~vA~J:~ia~~ WHERE: -·--.. -------'s-• , __ _ NDTE: l"I.M:EMtHr TO BE ~~ ~OHI.Y. ___ --~ \ ••• \ ""'+-.. INDICATE) ON p ~ LOG TA8L£ NI~~ St£ET AR£ CON --------•• I <''-.! ~-~~~----\ 2.. INSTAU. Stt.T fEHCES Wl'iERE DESIGNATEtl ON THE P\ANS. 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BE USED. ~, '-.,. &. n£.VATIONS ~OCIATED W!Tll COHroURltfG 1J....... ~ AND Fl.OOOPI..AIN AAr.A5 ARE TO BE DIRECTED D ECOLOGIST IN THE flELl), 7, PARTIALLY BURY NID Pl.ACE LOCS IN THE [XCAVAT£D "'-COVE, LOO PI.ACOIOIT SHOWN IN TiiE PLNIS ARE SCHEw..TIC; ACT1JAl. PVGEMENT AHO > /ARIW«lEMENT TO BE OtrEIU,IINED BY THI: ECOLOGIST lN THE f\O.D. ANCHOR AS SHOWN IN PLAN OETi\ll.S. B. PlK:C e INCHES OF Sll1CW8Etl CAAvns WITTflN ,, THE M..COW: ARE,O., POI lYPICAI. SECTION, SHffT 15. -I. flEMOII[ ITMPOR.YY STA81UZUI CONS1RIJCTIOt,I 0011ANCES Nm Nn OTI-£R EROSION CONTROL MfASURES STllL INSTAlil11 AT TH[ SIT[. 1 O. PUtHf EMERCENTS A.NO SHRUBS IN Al.COVES ,1 'ACCORlllNG TO P1.AHi1NC PIAN. \'-', '"\' '\ ., ,, ' ' ' CALL 2 WOFIC).IQ OAYS 8EFOAE YW OICl HI00-424-5555 .. ' ~-W.S.La .... , t _,, '""' ~KlngCounty · -...-.. --.... , ..... "' :::.::.i:--::.~ FE ----T-~ 1 ? 1011 ~A~ PlN+ WETl.NI) NC l'FARAN MTDATION 9TA. 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"" -1·0.r. -----. ... ,r...._ , .. ----u..111o1 ... i't-t, l/t.1·oi.-"" .....,J·o.c. -70.C. , .... -.. ----,,,_ .. ._,.._,. -----u..--.f/~1/J.I"-"" --J'D.C. .... ,.,u: ,~-·--, ... m.--·-.. ~ .. --···-...... J'QC May Creak Riparian Buffer Plantlngt0 o o~ ~~ o , .... ,...._ ----.,..._,, .... ,. Permanently Saturated Areas, 0 '!. ~ o O O o O ~ M-ll<"·I·-Stations 7+00 to 13+50, 19+00 to 29+00 """'70.('. -------, __ --.. _ w -·= May Creek Wetland Enhancement Planting • ~· _,, U..-7 .... IIT-1" Plan • west of 148th Ave SE -----· • l,'IDI ·--"~ Plnt)'O.C. u..-.,rr.-._11:,.i• ··---11-, ---·--,.M ---·---ri.70.C. U..-1'1-IIM" -.-.. --&·-. .... -1--·------,.M .... 1'"0.C --= ------.,..-1r :::70.C. - umr;mnN PJ AN NQJfS ----u..~ ........ 1-112-1" ·---·= -"""' \, MITICATION PLWnNG Pl.ANS REl'RESEHT A CONCO'TlW. PlANT lAYOOT. ALL MmGATIOH Pl.NmNQ PREPARATION Will BE ----u..--.r1-111-r ,_ DIRCCTnl IN THE F1El..D BY TH:E ECCll.OGISr. -...... 70.C. 2. PUNTNl StWi. TAA! Pl.ACE tlURlNC THE llOfU,w,fJ SEMON (OCTOBCR 15lli THROUGH MARCH J1ST). """"' "" "P\AHTS W1U. 8E JHST.w..m nR>UGH PROPEX (OR EQUl'IAL.EHT). "' BE AU.OWD> AT 01HER TlW£S N1tFI REVIEW AND WlfflTEN APPROVAL B"I' THE ECOlDCIST. NOTtS OH SlfEET 18. 3. Al'f>LY SHEEI" WU1..CH 1'S DlltEC1m BY ECOlOOIST Wl1HIN THE FlOOOPVJN EXCAVATION AREA.5 AND ALL PUHTINC ARrAS. 4. IN ALL PI.ANTJNO AREA.5 WHERE REED ClNARY GRASS IS MIESENT, COVER REED CANARY CAASS wtT1-l SHEET MULCH (OR A SIMllAR BMRIER Wit[RW.. "5 ~ BY THE ECCl1..00IST) ~ NEID£D ,V,,O O!RECTD) BY ECOl.OG!ST. STN<[ IN PLACt USING LIVE STAKES. 5. PU.NT STNCES AM) TREES ,S llCRECTlll 8Y THE ECOLOGIST THROUGH TliE SHEET 1M.CH {OR EOUIVALENT). 6. HO T~ HERBICIO[, Oil l"!:RtlJZ£R 5""l1. BE USED IN M PlNmNG AREAS. c·ty , ot Renton CALL 2 WORKING DAYS llEFOOa YOU DKl Planning Div;~,--1--8()()-424-5555 (lHIOICIIOl.f<Dutur,u,c,,,_"'(_ -DON Al..,.,~ P.E. 1---u Ml~~aurr- MAY CREEK DRAINAGE IMPROVEMENT '""' -01-lOl 6 ·~ 01-2010 ~~ ....... ' ---,, =~. 1048111 "' ·~ 02-2010 ....,, ... 7 -=-1.,2013 "'"" ... ---:RAY. PI.S 02-2010 ---F&IASUTATX)N' f'U,N, sam,; I ft~-ffil '--·" ~ fr:»~::::=-PI...ANTNl TAEI..E9 Ne, NOTES IIDDIDflDIDloU, • 2006-16 -• -""I.S'l-•""l/\~V~ '~[Q) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 CITY OF RENTON NOV O 4 2D1r RECEIVED CITY CLERK'S OFFICE BEFORE THE HEARING EXAMINER FOR THE CITY OF RENTON RE: May Creek Drainage Improvement Project Special Grade/Fill Permit and CAO Variance ) ) ) FINAL DECISION ) ) ) ) ) LUAll-065, V-H, SP ) ----==-:c.:.__::.::::.L..:..__:_.:,c.:::.c:.___ ____ _ Summary • 16 King County has applied for a Special Permit for Grade/Fill and a variance to critical area regulations for a dredging project to May Creek designed to reduce the duration of one year flood events for 17 upstream properties. The permits are denied without prejudice. There is insufficient evidence to 18 establish that the drainage project will not adversely affect downstream properties by increased erosion. '•\, 19 20 21 22 23 24 25 26 Testimony Jennifer Henning, Renton current planning manager, spoke on behalf of the City of Renton. She noted that the hearing is a permit for grade and fill and also a variance to the critical areas regulation in order to allow for some removal of vegetation along the stream. The area in Renton is only 3.75 acres, composed of the dredging area as well as vegetation removal. Sediments, fines and cobble will be removed. Vegetation that obstructs the channel, primarily canary grass, will also be removed. The project site contains a Class ID wetland. The City has five classes of wetlands. Class ID is the third most significant with a 25 foot buffer. SPECIAL GRADE/FILL PERMIT AND CAO VARIAN CE -I EXHIBIT 31 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 Ms. Henning noted that May Creek River Mile 4.3 to 4.9 contains the entire project area. The portion in Renton is only a smallportion of the project, the western limit of the project area. Large woody debris will be added to the stream as mitigation. A couple stream alcoves are added to serve as fish habitat. The project involves a temporary access road for the equipment used to do the dredging and mitigation. The project will improve the flood capacity of the area, which is flooded during most of the year. The project will increase the flow capacity and will allow some use of the land that is usually flooded. The dredging will remove accumulated sediment that will be spread throughout the project site instead of transported off-site. Enhancement native vegetation will be installed. The Department of Ecology has required fencing around the project area composed of three strand barbwire, which is standard for areas along May Creek to keep livestock outside of the stream buffers. There is some disagreement as to where to place the fence on one of the lots affected by the project. The City's main interest is that sensitive area signs be posted and that the fence doesn't obstruct wildlife movement. Ms. Henning summarized the mitigation required for the project. Only 392 cubic feet of sediment will be dredged and obstructing vegetation removed. The stream will be diverted during the dredging to prevent water quality impacts. Noise and dust impacts will be temporary during construction only. On-site noise levels during construction will reach dba, but this dissipates away from the site and there will be no work on weekends. The variance from critical area regulations is necessary to remove vegetation and sediment within a sensitive area and buffer -May Creek and the Class ill wetland. The project site is fairly flat. The project protects the public health and welfare because public access will be very limited. The project will reduce flooding which promotes public safety. Staff concurs with the Applicant's hydraulic analysis that there will not be adverse erosion impacts downstream and downstream flooding. The project is consistent with the City's comprehensive plan because there is no change in use of the land. The Applicant did review alternative courses of action and they determined that the measure taken was the least disruptive of the sensitive areas and the most consistent with the County's budget limitations. Wetland areas will be restored and invasive species removed. Measures will be taken to prevent sediments from re-entering the stream. The project will not create any net loss in stream function. The project involves one to one compensatory mitigation so there is no net loss. The project was evaluated under Section 7 of the Endangered Species Act. Exhibit 20 was admitted into the record as the ESA consultation for the project. The consultation reveals that there will be no adverse impacts to endangered species. There were some comments submitted from the Muckleshoot Tribe for the dredging project as a whole (Ex. 17). Best management practices will be employed to protect ground and surface water quality. The Washington State Department of Ecology ("DOE") has denied 401 certification without prejudice only because DOE had a deadline to make a decision and King County is still working with DOE to acquire certification approval. Project mitigation involves IO years of monitoring. The Examiner asked the King County representative, Doug Chin, whether a foot bridge was a contributing factor to the flooding as alleged in some of the comment letters submitted on the project. Mr. Chin clarified that the dredging is designed to alleviate one year flooding. The bridges don't have any impact on the flows the project is designed to improve. The bridges affect larger storm events. SPECIAL GRADE/FILL PERMIT AND CAO VARIAN CE -2 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 Andrew Duffus, neighboring property owner, asserted that the 9/22/11 DOE letter was glossed over as DOE running out of time. DOE asked the Applicant numerous times to ask for information that hasn't been received. He noted that the project is an ill-conceived attempt to temporarily reduce flooding to protect horse pastures. Downstream properties already experience numerous flooding problems and can only access their properties through private bridges that are vulnerable to flooding and erosion. The preliminary report to the Examiner is flawed with gaps in relevant information. No reference is made to the 9/22 DOE letter. On 8/15/11 DOE released a memo from its senior hydrologist, Dr. Patricia Olson, who had reviewed all of the County's documentation and done a site visit. She questioned the lack of detail in the County's studies and design, the effectiveness of the project and cost/benefits. Dr. Olson publishes articles on rivers, lakes and groundwater issues and testifies as an expert witness. Her work was cited in the County's studies. Her memo should have been referenced in the staff report. The document should be given substantial weight. Mr. Duffus questioned the qualifications of staff to evaluate the application given the conclusions of Dr. Olson. On 9/1/11 DOE informed King County that it would have to deny the water quality certificate unless requested information was received by 9/16/11. DOE has repeatedly questioned the "effectiveness, purpose and need of the project". Just two weeks ago the Muckleshoot Tribe submitted a comment letter to DOE requesting that King County exhaustively consider alternatives before dredging May Creek. The wetland is a Class III wetland that is wet all year round, chest deep in the summer. Additional alcoves and other measures may be necessary to mitigate impacts. DOE and the Tribe are requesting larger planting buffers and other measures that could have greater clearing and grading impacts than those assessed. by the Renton staff. Mr. Duffus asserted that machinery would be roaming all over the project site to place snags. In the past the City has required cedar split rail fencing for critical areas, as demonstrated in LAU 05-83. That plat was in a project adjacent to the project within the same open space corridor of the project. Mr. Duffus also saw no broad public support for the project, which only benefits four horse pastures at the expense of downstream property owners. He also questioned whether the project could pass a cost/benefit analysis. There is a risk of liability for downstream environmental and property damage. There are 7 properties adjacent to the project. One property is a wetland, another is an undeveloped property that is also a wetland.· A third property is not used for farming. The remaining four properties have horse pastures with seasonal flooding. None of the homes on those properties are in danger of flooding. Conversely between 148th and Coal Creek Parkway there are 18 properties and eight of those homes are close enough to the stream to be flooded. Ex. 21 was admitted as the 9/22/11 DOE denial. Ex. 22 was admitted as the 10/3/11 letter from Mr. Duffus. Ex. 23 was admitted as a September 15, 2011 letter from the Muckleshoot Tribe. Ex. 24 was admitted as the joint notice from the Army Corps. Tom Carpenter, community activist, noted that the DOE d\:nial was without prejudice because DOE was out of time and a permit is expected to be forthcoming. The cause of flooding in the project area is well understood as resulting from development of the surrounding hillsides that has resulted in the deposition of tons of silt into the project area. Stormwater mitigation in the 1960's was not adequate to protect May Creek from these silt impacts. There has been a significant infestation of SPECIAL GRADE/FILL PERMIT AND CAO V ARlANCE -3 I 2 3 4 5 6 7 8 9 10 II 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26. ·invasive reed canary grass into the valley. Unfortunately extension agencies recommended their installation before realizing their adverse impacts. The deposition of sedimentation and the proliferation of the reed canary grass have completely altered the natural retention/detention functions of the valley and creek. The Stonegate Homeowner' s Association is very excited about the project because it will restore the hydrological functions to its predevelopment state extending to before coal was discovered in the valley and it was first developed. The project site is limited to the area where sediment has settled. The properties that benefit extend way up stream from the project site. Currently those properties are flooded six months out of the year, which is not consistent with the natural state of the valley. It is not correct to _assert that only seven properties will benefit. Wetland boundaries are far in excess of what they have been historically and these standing bodies of water are caused by the loss of hydrological functions of the creek. Historically there have only been two small wetlands on the entire seven mile stretch of the creek. One is in a small area not close to the project site and the other is at the mouth of the creek. Jeff Walker, an upstream property owner, noted that Mr. Carpenter had already covered much of what he was going to say. He added that his property has been used for agricultural purposes for over 100 years and that much of this property can't be used because of the flooding. He emphasized that the County are unbiased and that property owners and that there is a high vested interested in the project by numerous upstream property owners. He noted that the stream is a valued recreational corridor as well that will benefit from the project. Roger Coates, testified he was concerned that no one has proven that erosion to downstream properties won't occur. He is concerned that the increase in stream velocity will increase erosion on his property. Jean Rollins submitted a summary of citations from scientific experts demonstrating that 9 of the I 0 variance criteria haven't been met. She noted that the project is designed to benefit horse pastures at the expense of downstream properties. The County doesn't know what will happen downstream. Dr. Olson states that the hydraulic analysis is inappropriate. Experts conclude that it is incorrect that the project will not create downstream erosion. Experts believe that the project will harm the stream and wetlands. The project serves private property, not public need. Better alternatives have been ignored. The 0.04% in flood reduction is not worth the project cost and impacts. Dr. Olson disagrees with King County conclusions on downstream erosion impacts and deposition of sediment. Dr. Olson concluded that the existing transport modeling needs independent review. Compensatory flood storage is not provided. Fish species are jeopardized as Green Creek is home to Chinook, Sockeye and Coho. Green Creek is close to the wetland. The 401 certificate was denied because King County could not demonstrate that water quality standards had been met. The 9/22/11 DOE letter shows that King County has not provided information necessary to approve the permit. There was no "time crunch" as DOE had requested needed information over an extensive amount of time. The Army Corps and DOE have repeatedly questioned the need and purpose of the project. Dr. Olson wrote that the channeling project is akin to trying to channel a bathtub that has more inflow than outflow. The scientific studies used for the project has been invalidated by scientific authorities. The long marsh creek plan is not a mitigation plan. Compensatory flood SPECIAL GRADE/FILL PERMIT AND CAO VARIAN CE -4 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 storage has not been provided. The alcoves are insignificant. If the alcoves fill with sediment fish will not be able to access the site. There is no monitoring plan for the dredging of the project. The Examiner should take a no risk approach to the project pursuant to RMC 4-9-25(F). Jim Bonwell, owner of the first downstream private bridge, noted that the County comes up with a different plan at each hearing. He was born near the creek and his parents live near the headwaters of the creek. His grandfather told him they used to dredge the creek so it's inaccurate to say that the project will return the creek to natural conditions. There are dredge materials on his property that he discovered 25 years ago when he acquired his property. He overheard some County consultants walking the creek stated it was classic Coho habitat. He understands that upstream properties are flooding but this is what the Valley properties are designed to do. On his property there is a rock vein that serves as a high water mark and this is the reason for the flooding and that's not going to be changed by the dredging. Jerri Wood has lived in May Valley her entire life. Part of the flooding is due to overdevelopment. Her concern on the dredging and mitigation is that there are experts on both sides. The experts opposed to the project validate her experiences and those of her mother in the valley. The City has failed to follow its urban separator regulations. Her mother's neighbor repeatedly channels storm water onto her property in violation of Renton standards but Renton won't enforce those standards. If you dredge May Creek her mother will lose her backyard and septic system. With the erosion already happening, the removal of the sediment by the project will destabilize shoreline trees that will fall onto her mother's home. The City of New Castle is also responsible for the overdevelopment. The creek as whole should be considered and impacts to persons such as her mother should be considered. A more collaborative process is needed to solve these problems. Julie Bonwell testified that dredging can't be good for an environmentally sensitive wetland and salmonid stream. Up until 22 years ago the project area was an overused, overgrazed horse pasture and it has taken years to be restored. The wetland is doing its job in filtering water and serving as an aquifer recharge area. The stream level rises by several feet during major storm events. Woody debris flowing down the stream causes property damage. She is concerned that the woody debris proposed for mitigation won't be sufficiently anchored and will wash out her bridge, which is the only way she can access her home. Ex. 25, Jean Rollins written materials, was admitted. The Examiner inquired whether the County wanted an opportunity to reserve objection until it had an opportunity to read it and the County stated they had no objection and just wanted a copy. · The Examiner inquired whether King County had any rebuttal and noted that he was particularly interested in any response to the Dr. Olson materials, since that represented credible scientific evidence that he will take seriously. Mr. Chin noted that a biological evaluation on fish impacts had been done for the project and that the National Marine Fisheries Service concurred in the evaluation. The Washington State Department of Fish and Wildlife has also approved a hydraulic permit for the project. King County first received comment on the project from DOE on September SPECIAL GRADE/FILL PERMIT AND CAO VARIANCE -5 I 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 1, 2011. DOE gave King County until September 16, 2011 to respond to the comments. Part of those concerns were based upon input from Dr. Olson, but King County had not seen her memo until October 3, 2011. King County responded to the DOE comments on September 16, 2011. On September 22, 2011 DOE notified the County they were up against the wall and had to meet the statutory deadline and didn't have time to approve the permit so their only course of action was to deny the permit with [sic) prejudice. The County will address all the questions raised by Dr. Olson with DOE in a near term meeting that is being set up at this time. Mr. Chin asked to enter a sediment transport study into the record, which is located at the King County website. The Examiner stated that he could leave the record open for the County to supply the document, but that the record would also have to be left open for public response and the County would then have an opportunity to provide rebuttal to that response. Mr. Chin stated he was fine with that process. Mr. Chin noted that the woody debris would be anchored into the ground and embedded with "what is appropriate", which may be [inaudible)-filled anchors or whatever is necessary to keep the debris in place. Mr. Chin also requested to submit a hydraulic analysis, which was admitted as Ex. 26. He noted that the project will provide better flow to prevent one year storms. The buffers will be replanted with native vegetation that should out compete the reed canary grass that will be removed. The replacement of the reed canary grass will ensure longevity for the project. The long marsh creek project is designed to prevent the deposition of sediment from long marsh into May Creek. The long marsh creek project will trap sediment before it gets to May Creek, thereby maintaining the functions of May Creek and extending the life of the project. Jeff Burke, King County, acknowledged.that 0.04% is a very insignificant change in the duration of flooding. The project is designed to focus on flows between 6 and 50 cfs. Any storm goes overbank into flood areas. No changes are being made to the flood area, just to in-channel capacity. This results in significant changes to flood duration in the flood areas of 20%. There will still be flooding. The duration of flooding for small storms will change. Mr. Burkey testified that there will be more conversations with DOE on the Olson memo. The 0.04% change in duration of 50 cfs referenced in the Olson memo is only a 7 hour difference per year. As to her comments on stream power, stream power is based on time not just magnitude. The change in duration of the stream power is only on the order of a few hundredths of a percent. Duration is a major component of erosion impacts. Mr. Burke is a hydrologist with King County and has served in that capacity for over 20 years. He has also done contract work for DOE. Lindsey Miller, King County Environmental engineer, is a wetland ecologist by training. The impacts to the wetlands are only temporary resulting from wetland enhancement designed at suppressing canary grass. The work in the wetlands is limited to replacing non-native canary grass with native species, which is an enhancement project. There will be no change in flood storage or extent of flooding in the wetlands. The project will also further mitigate impacts from upstream development. Don Althauser, engineer of record for design of the project, testified on the private downstream SPECIAL GRADE/FILL PERMIT AND CAO VARIAN CE -6 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 bridges. There are two private downstream bridges, one owned by Duffus and Rollins and the other by Bondwell. The changes in hydrology are small and well within the capacity of the bridges. He can't testify as to the condition of the bridges. The second bridge doesn't appear to have any exposure to erosion. The Bondwell bridge does appear to have some exposure. He can't propose upgrades to private bridges. He does not see that the project will create any adverse impacts to the bridges. The Coates property was inspected. It is eroding and unstable. Bioengineering stabilization measures would probably stabilize the property. The project will not further destabilize the property. The project was designed to assure no increase in downstream erosion. The sediment transport study for the project found that the flow rates necessary to create erosion indicate that the flows are well above 75 cfs and may be as high as 200 cfs. The project will only increase flows by 6 cfs, which is well below the range of concern. Mr. Chin noted there were a number of senior level biologist, ecologist, geologists and consultants worked on the project and provided their expertise. Jennifer Henning introduced a few more exhibits. Ex. 27 was admitted as the 2/9/22 Sediment Assessment Report. Ex. 28 was admitted as the HP A approval. Ex. 29 was admitted as the 2/11 May Creek Drainage Improvement Biological Evaluation. Ms. Henning identified some administrative permits required for the project. She referenced RMC 4-3-110, which identifies the urban separator map and shows that the project area is not in the urban separator. Within the separator area there's a requirement for no fencing to allow for the passage of wildlife. This requirement doesn't apply to the project area, where fencing is allowed. She clarified that the Olson memo was not submitted to the City by DOE as their comment on the project application. It was provided by Mr. Duffus. Exhibits Exhibits 1-17 of the exhibits identified at Page 2 of the staff report were all admitted into the record with no objections from the public. Ex. 1, the "project file" will be limited to the staff report, since the exhibit title otherwise does not provide notice to the public of what documents are specifically included. The following exhibits were admitted during the hearing: Exhibit 18: Vicinity Map with project location highlighted in yellow. Exhibit 19: Wetland and Riparian Mitigation vicinity map, Sheet 14 of 18 Exhibit 20: 3/10/11 ESA Consultation · Exhibit 21: 9/22/11 DOE Section 401 denial Exhibit 22: 10/3/11 comment letter fr A. Duffus Exhibit 23: 9/15/11 Muckleshoot comment letter Exhibit 24: Army Corps/DOE Joint Public Notice, NWS-2010-158 Exhibit 25: 10/4/11 comment letter fr Jean Rollins Exhibit 26: 12/17/10 Hydraulic and Hydrologic Analysis Exhibit 27: 2/9/11 Sediment Assessment Exhibit 28: 123184-2 Hydraulic Permit Approval Exhibit 29: 2/11 Biological Evaluation SPECIAL GRADE/FILL PERMIT AND CAO VARIAN CE -7 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Exhibit 30: Landscaping Plan Exhibit 31: Sediment Transport Study Exhibit 32: Two 10/13/11 emails fr Debra Rogers re transport study Exhibit 33: 10/13/11 email from Jim and Julie Bonwell re transport study Exhibit 34: 10/13/11 email fr Gary Amundson re transport study Exhibit 35: 10/14/11 email from Wayde Watters re transport study Exhibit 36: 10/14/llemail from Doug Chin re transport study1 FINDINGS OF FACT 1. Applicant. King County Water and Land Resources Division 2. Hearing. A hearing was held on October 4, 2011 at 1:00 pm at the Renton City Hall City Council Meeting Chambers. The Examiner left the record open for submission of the sediment transport study (Ex. 31 ). Mr. Chin was given until Thursday ( 10/6/11) to supply the report ( or a weblink) to the City. The public was given until a week from Friday (10/14/11) to supply written comment on the report and the County was given until the following Wednesday (10/19/11) to reply. Emails were received after the October 4, 11 hearing questioning whether comments were limited to the transport study. The Examiner stated both during the hearing and at the end of the hearing that the purpose of leaving the record open was to provide an opportunity for the public to review the transport study, because the transport study was not available during the hearing for review and response. All other exhibits were presented for review during the hearing. The Examiner provided an opportunity for all hearing participants to review all other exhibits and to object to their admission. No requests to leave the record open on any exhibit were made during the hearing and the Examiner only left the record open for comment on the transport study. King County did not reply to the transport study comments submitted by the public. The Examiner confirmed with staff that the public comments had been forwarded to the County along with confirmation that the reply deadline was October 19, 2011. · Substantive: 3. Description of Proposal. King County requests a Special Permit for Grade/Fill and a variance to critical area regulations in order to improve in-stream flow conditions along the reach of May Creek between approximate River Mile ("RM") 4.3 and 4.9. The project would result in the removal of approximately 392 cubic yards of accumulated sediment from approximately 162 lineal feet of the May Creek Channel, and the removal of obstructive vegetation (reed canary grass and willow branches) for approximately 540 lineal feet of river channel. The project is located in May Valley on the south side of SE May Valley Road near the cities of Newcastle and Renton. The 25 1 Mr. Chin's email does riot address the transport study directly. However, it does indirectly argue that the Olson memo criticizing the transport study may not be the official position of DOE and that King County will resolve any 26 concerns raised by Dr. Olson should her memo become the official position of DOE. SPECIAL GRADE/FILL PERMIT AND CAO VARIAN CE -8 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 project within Renton would occur on a parcel that is approximately 3. 75 acres. The project site contains a Category 3 wetland and a Class 2 salmonid stream (May Creek). As mitigation for removing sediment and vegetation, 15 feet of riparian/wetland vegetation would be planted on both sides of May Creek, and also outside City limits. Enhancement would include approximately 0.24 acres of off-channel alcoves, reed canary grass suppression, planting with native vegetation and large woody debris placement. All dredged materials will be deposited on site, eliminating the need for truck export. Additional vehicular access during project installation within the wetland and floodplain will be provided using rubber tired or tracked equipment. The project is expected to commence during the first approved fish window after receiving the permit, likely in 2012. SEP A environmental review was conducted by King County as lead agency. 4. Adverse Impacts. King County has failed to demonstrate that its project will not harm downstream properties through increased erosion. The impacts to downstream properties were of significant concern and anxiety to downstream property owners. The owners were concerned about impacts to footbridges, septic drainfields, flooding and eroding away of stream banks. The concerns of the property owners were confirmed by Dr. Patricia Olson in an August 15, 2011 internal DOE memo (Ex. 15). Dr. Olson is a PhD hydrologist employed by DOE to assess water quality impacts of projects such as that proposed by King County. She reviewed the project and wrote the memo as part ofDOE's Clean Water Act Section 401 certification review for the project. There is no question that Dr. Olson was both highly qualified and unbiased in her assessment of downstream impacts resulting from the project. In her memo, Dr. Olson raises several concerns over the County's analysis of the project. She wrote that it did not appear that the author of the sediment transport study, Ex. 31, was "well versed in fluvial geomorphology and channel response". She notes that County studies fail to identify the volume of additional sediments that will be transported downstream and where they will be deposited. She identifies several reasons why the methodology used to assess the potential for erosion is flawed and may underrepresent the potential for sediment transport. She concluded that she cannot make a determination concerning bank erosion of downstream properties given the flaws in the transport and hydraulic studies. She also disagreed with hydraulic study conclusions that flood frequency would be insignificant and noted that an increase in flood frequency increases the potential for erosion due to associated increases in stream power. At the bearing King County provided some verbal rebuttal to the concerns raised by Dr. Olson. Jeff Burke, a hydrologist, testified that the change in duration of the stream power is only on the order of a few hundredths of a percent and that this will have no significant impact on erosion potential. Don Althauser, project engineer, testified that in his professional opinion the project would not destabilize or erode the support of downstream bridges and that the project would not increase downstream erosion. He noted that the flow rates necessary to threshold sediment transport are well above 75 cfs and may be as high as 200 cfs and that the project will only increase flows by 6 cfs2• 2 It doesn't appear that Mr. Althauser identified the mean flow rate for May Creek in his testimony, but the hydraulic 26 study (Ex. 26) sets the rate as 9 cfs. · SPECIAL GRADE/FILL PERMIT AND CAO VARIAN CE -9 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 During the hearing and also in its written comment on the transport study (Ex. 36), King County discounts the issues raised by Dr. Olson because her comments may not represent the position of DOE and, if her comments do represent the position of DOE, they will be addressed at a later date. Those facts are largely irrelevant. Dr. Olson has provided a qualified and credible scientific opinion that the studies prepared for the project are flawed and incomplete. The fact that Dr. Olson's opinion may or may not represent the position of DOE only has _marginal relevance to the accuracy of her position.· The fact that King County intends to address her concerns at a later date does absolutely nothing to support a finding in this case that downstream impacts will be fully mitigated as required by the permitting criteria for the applications under review by the City of Renton. Permits are not approved based upon assurances from applicants that impacts will be addressed at a later date. Mr. Burke and Mr. Althausen did a fine job in responding to some of the issues raised by Dr. Olson. They take the position that the flows generated by the project are far below the thresholds for sediment transport identified in the transport study (Ex. 31) and the hydraulic study (Ex. 26). However, Mr. Burke and Mr. Althausen did not address Dr. Olson's issues with the accuracy of those much higher threshold points. Given the numerous and significant alleged flaws in the studies identified by Dr. Olson, there is no way of knowing from the record before the Examiner whether the threshold flows are indeed much higher than those generated by project. It is both alarming in the truest sense of the term and even suspect that King County is unable to defend the accuracy of its studies when alleged flaws are so clearly identified by Dr. Olson. Why were pebble counts used? Why weren't more data samples necessary? Why were pebble counts done on the channel instead of bars? Why weren't subsurface pebble counts done? Why wasn't any volumetric sediment sampling done? King County should be able to answer these questions. Apparently it cannot. King County was fully apprised of the significance of the Olson memo from both the examiner and the public. King County had ample opportunity to respond to the Olson memo. The Examiner advised King County during the hearing that the Olson memorandum raised significant issues and that he needed the memo to be addressed. The King County response was primarily limited to the verbal testimony from Mr. Burke and Mr. Althauser. King County did not request additional time to respond to the memo. In point of fact, King County was given another opportunity to respond to the memo in the reply it was afforded for comments on its transport study. Many of the public comments on the transport study referenced Dr. Olson's critique of the study. King County could have used the reply to address those Olson comments. Instead, King County didn't submit any reply, despite having received the public comments and a reminder from staff that the County could reply to them. Given the circumstances above, the Examiner has no choice but to find that the evidence is not sufficient to conclude that, more likely than not, the project will not adversely affect downstream properties with erosion. Despite multiple opportunities to assure the Examiner and the public that its methodology in assessing erosion impacts was not flawed as asserted by a qualified hydrologist, SPECIAL GRADE/FILL PERMIT AND CAO VARIAN CE -10 I 2 3 4 5 6 7 8 9 10 11 King County simply let the allegations stand, raising serious doubts as to the credibility of the studies. Substantial evidence in the record, the uncontested conclusions of Dr. Olson, establishes that the studies are flawed and cannot be relied upon to assess downstream impacts. The assessment of adverse impacts is limited to erosion impacts since that was the most significant issue raised during the hearings and all that is necessary to deny the grade/fill and variance applications. In any reapplication King County should fully address all issues raised by Dr. Olson as well as all other issues pertinent to project approval. Conclusions of l.aw Procedural: 1. Authority of Hearing Examiner. RMC 4-9-080(F)(2) provides that the hearing examiner is responsible for granting special permits for fill and grade. The code section provides that a special permit is required for the depositing of minerals or materials such as sand, gravel and rock. The 12 proposed dredging will involve the deposition of dredged materials on site, so a special use permit is required and subject to review by the Examiner. 13 14 The authority of the Examiner to rule upon Critical Area Ordinance variance ·applications is not so clear. RMC 4-9-250(B)(l) provides that the Community and Economic Development Administrator or designee shall have the authority to grant variances "from the following development standards when no other permit or approval requires Hearing Examiner Review". The requirement implies that 16 the Hearing Examiner shall review the variance request if an associated permit also requires 17 Examiner review, which in this case would be the special grade and fill permit. "(T]he following 15 development standards" that may be modified by a variance under RMC 4-9-250(B)(l) includes 18 those identified in RMC 4-9-250(B)(l)(c)(v), which are those "authorized to be requested as variances in RMC 4-3-050(L)". RMC 4-3-050(L)(8)(d) authorizes administrative approval of 19 dredging activities provided that if applicable criteria are not met, a variance pursuant to RMC 4-9- 20 250(B) is required. The staff report does not identify what Critical Area regulations are subject to the variance request and what corresponding parts of the project trigger the need for a variance. The dredging activity appears to meet the criteria for administrative approval by being necessary for flood hazard reduction purposes as required by RMC 4-3-050(L)(8)(d)(i)(a). The replacement of canary 21 22 grass with native vegetation and introduction of woody debris appears to meet the exemption criteria of RMC 4-3-050(C)(5)(a)(ii). Project features that may trigger the need for a variance could arguably be the stream alcoves and the temporary access plan. However, these features could also be 23 24 interpreted as implied necessary elements of an enhancement/dredging operation. If King County reapplies, staff may be able to conclude that the variance request is not necessary. In the alternative, if staff still finds the variance application necessary it should provide a more detailed explanation of why a variance is required. 26 25 SPECIAL GRADE/FILL PERMIT AND CAO VARIANCE -11 1 Substantive: 2 2. Applicable Standards. RMC 4-9-080(F)(4) governs the criteria for special fill/grade permits. RMC 4-9-250(B)(l0) governs the criteria for the CAO variance. Only those criteria that address 3 erosion impacts will be quoted and applied below since those standards on their justify denial of the 4 applications. RMC 4-9-080(F)(4): ... To grant a special permit, the Hearing Examiner shall make a determination that.. the proposed activity would not be unreasonably detrimental to the surrounding area. The 6 Hearing Examiner shall consider, but is not limited to, the following: ... Size and location of the activity ... 5 7 8 3. As discussed in Finding of Fact No. 4, there is insufficient evidence to support a determination that the amount of dredging proposed by the County will not create downstream 9 erosion that could adversely affect downstream properties. For this reason, there is not sufficient evidence to determine that the proposed activity would not be unreasonably detrimental to the 10 surrounding area. 11 RMC 4-9-250(B)(10): ... in lieu of the variance criteria of subsection B5 of this Section, 12 applications for public/quasi-public utilities or agencies proposing to alter aquifer protection, geologic hazard, habit, stream and lake or wetland regulations shall be reviewed for compliance with all of the following criteria: 13 14 15 16 a. Public policies have been evaluated and it has been determined by the Department Administrator that the public's health, safety and welfare is best served; ... e. The proposed activity takes affirmative and appropriate measures to minimize and compensate for unavoidable impacts. 17 4. Since the evidence is insufficient to determine whether the project will generate erosion l 8 impacts for downstream properties, King County has failed to establish that the public health, safety and welfare is best served by the project. The absence of demonstrably credible erosion evidence 19 also makes it impossible to determine whether affmnative and appropriate measures have been taken to minimize unavoidable impacts. The project does not comply with RMC 4-9-250(B)(l 0). 20 21 22 23 DlECISION The grade/fill permit and the critical areas variance applications are denied. The permit applications must comply with all applicable criteria and King County has failed to demonstrate compliance with the permitting criteria identified in this decision. Since denial is based upon the failure to provide 24 necessary information, the denial is without prejudice in case King County can produce the information necessary to demonstrate compliance with applicable criteria 25 26 SPECW.., GRADE/FILL PERMIT AND CAO VARIANCE -12 DATED this 8th3 day of November, 2011. Pliil A. Olbrechts . City of Renton Hearing Examiner Appeal Right and Valuation Notices RMC 4-8-IIO(E)(9) and/or RMC 4-8-llO(F)(l) pro·vides that the final decision of the hearing examiner is final subject to appeal to the Renton City Council. RMC 4-8-11 O(E)(9) requires appeals of the hearing examiner's decision to be filed within fourteen (14) calendar days from the date of the hearing examiner's decision. A request for reconsideration to the hearing examiner may also be filed within this 14 day appeal period as identified in RMC 4-8-11 O(E)(8) and RMC 4- 8-100(0)( 4). A new fourteen (14) day appeal period shall 'commence upon the issuance of the reconsideration. Additional information regarding the appeal process may be obtained from the City Clerk's Office, Renton City Hall -fh floor,. ( 425) 430-6510. Affected property owners may request a change in valuation for property tax purposes notwithstanding any program ofrevaluation. 3 This decision was initially mailed to the City of Renton on 11/2/11 with an incorrect signatirre date. The decision has been re-issued with a correct signature date. SPECIAL GRADE/FILL PERMIT AND CAO VARIAN CE -13 • 1 2 3 4 5 6 7 8 9 JO 11 12 13 14 15 16 17 18 19 20 21 22 CliY OF RENTON JA.N l 3 20\2 RECEIVED CITY CLERK'S OFFICE BEFORE THE HEARING EXAMINER FOR THE CITY OF RENTON RE: May Creek Drainage Improvement Project Special Grade/Fill Permit and CAO Variance LUAl 1-065, V-H, SP ) ) DECISION ON RECONSIDERATION ) ) ) ) ) ) ) King County has requested reconsideration of the denial of its applications for a critical areas ordinance variance and special grade/fill permit for the dredging of May Creek, Renton File No. LUAl 1-065, V-H, SP. The request is denied. Procedural Background 1, On November 11, 2011 the Hearing Examiner issued a decision denying the above- captioned permit application. 2. · King County filed a timely Request for Reconsideration, received by the City of Renton on November 17, 2011. In its request for reconsideration, King County pointed out that it had not received copies of letters submitted into the record that were critical of the Anchor QEA, LLC sediment transport study, Ex. 31. 3. By Order Authorizing Reconsideration dated November 28, 2011 the Examiner authorized King County to provide new evidence in response to the written comments King County had not 24 received on the sediment transport study. The Order included a schedule for submission of additional comments for all hearing participants. 23 25 26 4. Several new exhibits were entered into the record as part of the reconsideration process, SPECIAL GRADE/FILL PERMIT AND CAO VARIANCE -1 EXHIBIT 32 1 2 3 4 5 6 identified as follows: Ex. 36: Ex. 37: Ex. 38: Ex. 39: Ex. 40: 11/15/11 King County Reconsideration Request Order Authorizing Reconsideration 12/8/11 comment letter from Andrew Duffus 12/9/11 comment letter from Jean Rollins 12/21/11 comment letter from King County Analysis 7 The critical issue for both permit applications is the impact of dredging project on downstream properties. Project opponents presented a compelling report by Dr. Patricia Olson, Ex. 15, from the 8 Washington State Department of Ecology ("DOE"), who asserted numerous flaws in the studies used by King County to conclude that downstream properties would not be adversely affected. The 9 Examiner determined that Dr. Olson raised legitimate concerns and that King County did not 1 o adequately refute them. As detailed in the procedural background above, King County was given an opportunity to present new evidence in its request for reconsideration to rebut comments made by the public regarding the accuracy and validity of the sediment transport study, Ex. 31. These public comments primarily referenced the report provided by Dr. Olson, Ex. 15. The information 12 provided by King County in its reconsideration request still does not provide sufficient information to determine that more likely than not downstream properties will not be adversely affected by the project. 11 13 14 In its reconsideration comments, Ex. 40, King County largely agrees with the concerns of Dr. Olson 15 regarding the accuracy of the sediment transport study. King County's primary defense is that it didn't rely upon the flawed data, which comprises the bulk of the sediment transport study. As best 16 as can be discerned from King County's arguments, King County ultimately concluded that the 17 project wouldn't increase downstream erosion because the flows that initiate sediment transport observed at three monitoring stations significantly exceeded the extra flows generated by the 18 project. These relatively simple observations would have been readily apparent to Dr. Olson, who still determined that further analysis was necessary. Corroborating Dr. Olson's skepticism is the 19 fact that King County also acknowledges that the transport thresholds at the monitoring stations aren't representative.of those that may occur downstream. Of further concern is that King County 20 also readily admits that it did not provide any detailed assessment of damage that may occur to downstream properties. With this background, it is not possible to conclude with any reasonable degree of confidence that downstream properties will not be adversely affected by the project. 21 22 23 The points raised by Dr. Olson are more fully addressed as follows: HEC-RAS Program. In Ex. 40 King County acknowledged that the HEC-RAS program should not 24 be used to evaluate erosion potential. It does appear that the conclusions of the sediment transport 25 study do not appear to use model results in deterinining the estimate of threshold motion, assessed at pages 22-24 of the study. The HEC-RAS Program may have been used to input some values into 26 the formulas used to estimate critical shear stress, but that was not apparent from the text of the SPECIAL GRADE/FILL PERMIT AND CAO VARIANCE -2 . ' 1 report. 2 Median Pebble Size: King County agrees with Dr. Olson that the median pebble diameter size 3 identified in the report may be inaccurately smaller than actual site conditions. King County pointed out that its conclusions were not based solely upon median pebble size. The "estimate of 4 threshold motion" section of the study, referenced in the preceding paragraph, was expressly based upon median pebble size. The only conclusions in the study made independently of median pebble 5 diameter appear to be the generalized empirical observations from high flow events at the three monitoring stations. As previously noted these conclusions were that soil transport only occurs at 6 flow rates that significantly exceed those created by the project. In short, the bulk of the analysis in 7 the sediment transport study was not sufficiently accurate to support any reliable conclusions on downstream property impacts. 8 Monitoring Site Observations. Although the King County conclusions appear to be based almost 9 entirely upon observations from its monitoring stations as opposed to HEC-RAS modeling, King County admits that the monitoring stations may not be representative of all portions of the stream. 1 O In its reconsideration request it acknowledged that the erosion threshold at the Duffus property was probably at the lower end of the range of 73 to 230 cfs. This low range is a significant departure from the conclusion of the sediment transport study that the overall erosion threshold is 275 cfs. 11 12 Further, there's no indication in the record that the Duffus property even represents the lowest end of the range. If the threshold has this much variability, it is difficult to understand how any single threshold can be assigned to the stream as a whole. It would appear that a far more relevant inquiry would be what the lower downstream thresholds would be and whether the increased flows 14 13 generated by the project would create cumulative flows that exceed them. 15 Site Specific Impact Analysis. The King County reconsideration request expressly stated that the 16 · sediment transport study was not designed "to evaluate site specific issues and concerns of the individual landowners at the specific location visited by Dr. Olson" and that the study "was not 17 designed to and did not conduct a detailed analysis of risk to any specific private infrastructure elements". The Examiner recognizes that King County qualified its statements as not providing any "detailed" analysis of site specific impacts. Under different circumstances King County could very · 19 well support a finding of no downstream impacts with these types of generalized conclusions. 18 However, the generalized conclusions of this report are based upon inaccurate pebble data and 20 monitoring data that does not accurately represent the conditions of all downstream stream sections. With flawed general conclusions and no site specific conclusions, it cannot be determined that more likely than not that the project will not cause adverse downstream impacts. 21 22 23 Overall Conclusions. King County appears to be arguing that the shortcomings of its data and analysis are of no consequence given the wide disparity between the nominal increased flows generated by the project and flows necessary to trigger sediment transport. King County also takes 24 the position that any more precise analysis would not yield any more useful results, given this disparity. One is left with the impression that King County has loaded the record with extensive data and studies to support its position, only to subsequently argue that most of that data and 26 analysis was not used by the County in its decision making when tasked to defend it. The existence of extraneous information is understandable in most cases. Anchor QEA was probably just 25 SPECIAL GRADE/FILL PERMIT AND CAO VARIAN CE -3 ,. I demonstrating that it had done its due diligence and completed as much analysis as could be reasonably expected within the limitations of sediment transport. science. The problem in this 2 particular case is that a qualified expert, Dr. Olson, provided very compelling evidence that more 3 useful information could have been reasonably acquired. Almost all of Dr. Olson's conclusions on the short comings of the studies were validated by King County. If she was correct on all these 4 issues, it reasonable to conclude that she was also correct in determining that more could have been done to assess downstream impacts. 5 6 DECISION 7 The grade/fill permit and the critical areas variance applications are still denied without prejudice. 8 All findings and conclusions of the November 11, 2011 decision shall remain in place. In addition, those findings and conclusions are supplemented by the exhibit list, findings and conclusions of this 9 decision on reconsideration as well as the exhibit list identified in the Order on Reconsideration. For the reasons discussed above, there is insufficient evidence to conclude that the project will not 10 adversely affect downstream property owners. Should the County exercise its option to re-apply, it is recommended that the City hire an independent third party reviewer to assess the validity of the conclusions of King County. In the alternative, evidence that King County has resolved the 12 concerns of Dr. Olson would be equally persuasive. The County should also recognize that the issues addressed in this reconsideration decision solely address erosion impacts. Potential flooding impacts also need to e addressed in more detail. 11 13 14 15 16 17 18 19 20 21 22 23 24 25 26 DATED this 9th day of January, 2012. ~p- City of Renton Hearing Examiner Appeal Right and Valuation Notices RMC 4-8-11 O(E)(9) and/or RMC 4-8-11 O(F)(l) provides that the final decision of the hearing examiner is final subject to appeal to the Renton City Council. RMC 4-8-11 O(E)(9) requires appeals of the hearing examiner's decision to be filed within fourteen (14) calendar days from the date of the hearing examiner's decision. A request for reconsideration to the hearing e examiner may also be filed within this 14 day appeal period as identified in RMC 4-8-11 O(E)(8) and RMC 4- 8-100(G)( 4). A new fourteen (14) day appeal period shall commence upon the issuance of the reconsideration. Additional information regarding the appeal process may be obtained from the City Clerk's Office, Renton City Hall-7th floor, (425) 430-6510. SPECIAL GRADE/FILL PERMIT AND CAO VARIAN CE -4 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 Affected property owners may request a change in valuation for property tax purposes notwithstanding any program of revaluation. SPECIAL GRADE/FILL PERMIT AND CAO VARIANCE -5 ' City of IReD11ftOD11 ~ityof RA . , tanning o·-nto, lAN[O) USE PERM~1' , l\lision F[B I 2 2013 MA~TE~ APPl~CA 11~(Q)Nij;,f;0o-. --...,., l'./ ,~ /I'll I PROPERTY OWNER(S) I PROJECT INFORil/lATION PROJECT OR DEVELOPMENT NAME: NAME: Stonegate Homeowners Association May Creek Drainage Improvement Project (9A1205) Happy Longfellow, President 5405 NE 24'" Ct PROJECT/ADDRESS(S)/LOCATION AND ZIP CODE: ADDRESS: Open space on the west side of 148th Avenue SE Just CITY: Renton ZIP: 98059 south of Its Intersection with SE May Valley Road In Renton, WA 98059. KING COUNTY ASSESSOR'S ACCOUNT NUMBER(S): TELEPHONE NUMBER: (425) 204-1119 I APPLICANT (If other than owner) I 803540TR-A Doug Chin on behalf of King County Water EXISTING LAND USE(S): NAME: Open Space Tract and Land Resources Division PROPOSED LAND USE(S): King County Water and Land COMPANY (if applicable): Open Space Tract Resources Division EXISTING COMPREHENSIVE PLAN MAP DESIGNATION: ADDRESS: 201 South Jackson Street, Suite 600 Resldentlal -1 PROPOSED COMPREHENSIVE PLAN MAP DESIGNATION CITY: Seattle ZIP: 98104 {If applicable) Residential • 1 EXISTING ZONING: TELEPHONE NUMBER: (206) 296-8315 R•1 I CONTACT PERSON I PROPOSED ZONING (if applicable): R-1 SITE AREA (In square feet): NAME: Doug Chin, Project Manager Approximately 33,600 square feet SQUARE FOOTAGE OF PUBLIC ROADWAYS TO BE COMPANY (if applicable): King County Water and Land DEDICATED: Resources Division Not annllcable. SQUARE FOOTAGE OF PRIVATE ACCESS EASEMENTS: ADDRESS: 201 South Jackson Street, Suite 600 N/A PROPOSED RESIDENTIAL DENSITY IN UNITS PER NET CITY: Seattle ZIP: 98104 ACRE {If applicable) Not annllcable. TELEPHONE NUMBER ANO EMAIL ADDRESS: NUMBER OF PROPOSED LOTS (If applicable) Not applicable. (206) 296-8315 doug.chln@klngcounty.gov NUMBER OF NEW DWELLING UNITS (if applicable): Not applicable. F:IDOUGC\DOUGCHIN\May Creek 2010\Rcoton Permiull.and Use Permit Master Application\Stonogate Reoton I EXHIBIT 33 ' ,-.~., . DJECT INFORMATION lco1 NUMBER OF EXISTING DWELLING UNITS (if applicable): PROJECT VALUE: Not applicable. $350,000 (includes project area outside City limits) SQUARE FOOTAGE OF PROPOSED RESIDENTIAL BUILDINGS (if applicable): Not applicable. IS THE SITE LOCATED IN ANY TYPE OF ENVIRONMENTALLY CRITICAL AREA, PLEASE INCLUDE SQUARE FOOTAGE (if applicable): SQUARE FOOTAGE OF EXISTING RESIDENTIAL BUILDINGS TO REMAIN (if applicable): Not applicable. SQUARE FOOTAGE OF PROPOSED NON-RESIDENTIAL BUILDINGS (if applicable): Not applicable. , . SQUARE FOOTAGE OF EXISTING NON-RESIDENTIAL BUILDINGS TO REMAIN (If applicable): Not applicable. NET FLOOR AREA ON NON-RESIDENTIAL BUILDINGS (if applicable): Not applicable. NUMBER OF EMPLOYEES TO BE EMPLOYED BY THE NEW PROJECT (if applicable): Not appllcable. Q AQUIFIER PROTECTION AREA ONE Q AQUIFIER PROTECTION AREA TWO Q FLOOD HAZARD-AREA Q GEOLOGIC HAZARD Q HABITAT CONSERVATION • SHORELINE STREAMS & LAKES • WETLANDS LEGAL DESCRIPTION OF PROPERTY · (Attach leaal descriotion on seaarate sheet with the following Information Included! sq. ft. sq. ft. sq. fl. 5,300 sq. ft. 28,300 sq. ft. SITUATE IN THE SECTIONS 2 & 3, TOWNSHIP 23N, RANGE 5E, IN THE CITY OF RENTON, KING COUNTY, WASHINGTON TYPE OF APPLICATION & FEES List all land use applications being applied for: 1. Grade & Fill Permit 3. 2. Variance 4. Staff will calculate applicable fees and postage: $ AFFIDAVIT OF OWNERSHIP I, (Print Name/s) See attached easement. , declare under penalty of perjurl under the laws of the State of Washington that I am (please check one)_ the current owner of the property Involved In this application or_;/_ the authorized representative to act for a corporation (please attach proof of authorization) and that the foregoing statements and answers herein contained and the informatiol1 herewith are In all respects true and correct to the best of my knowledge end belief. ttached easement. · i 1,1 • I ,..,~·) l,·,tl) "". '/ signed thts Instrument and acknowledge it to be his/her/thefri}ee and ~tary 1 'It. ' I certify that I know or have satisfactory evidence that tt ... plN N·• f'..l ll./ , • ~ ·• ": 1 [[,, ~ act for the uses and purposes mentioned in the lnstrw'nent. ~,,,,:~"';~;:,; .. ,,, v)J/JJL 'jr) , "-j);(/L 1J)7l.._ $~ \~~\\:,\~ii' 1f\!t!_1,,, Notary Publlc in and for{he State of Washington .#' ........ ~SIO]w l 11 1t1l'-'~ -("'S,-lgn-a7tu-re,-o-;-f=0w-n-e-ccr1R""e-pr-es-e-:snt-:sat,-iveCS")--,i\=µl:~,~~~~~,,.~i % · 1 {? o {-' ' i()/'\ 11i?:,,"ni\ iu in'~ igotary (Prtnt)'v(:,JJ,,11))1 • '-4 ~ V \cL' f ' \ ~--u,jj ~\ ;vs1.'c,t:. /ct_J.yappolntmerrtexplres: B'/fq{t4: , >.:•,, 19-\ ""'":II.. "f I .,,,;,(i" oi!im\-:., .... ,,,~~, F;\DOUGC\DOUGCHIN\May Creek 2010\Renton ~~~1sifi;·~'\.~ £Ill Master Application\Stoncgate Renton Master App Form.docx f"IJll\\\,~\\~~I -2 - PLEASE INCLUDE THE PROJECT NUMBER WHEN CAW NG FOR PR'OPER FILE IDENTIFJCATION NOTICE Of APPLICATION " Mastw 1.p,.ia11 .... llu Mffl ffi.d •nd •«•smod with ti.. De,..vnont <>I Community r.. E=noml, Donlo;,pmonl !=I-Plannlns Dl.!slon of tho Oty of Rento11. 11>• lollowlns brlsl!r d-=rll,...,. lhe •J>Plk•llon and u.. na,canuy f'ubllt Appro..-lL D4TI. OF NOTICE OF APPUCATION: l'ROJ:t:CT NAME/NUMB Ell: Mard\21,ZDU Moy Cr"I: Dnlnlp tmpn,,,,emenl Project/ LU"13-0X:llll7, SP, V-11 l'RDJECT OESCUmON: NopUc:1n1 n,quuts; HHrillll Eumlr>er Oppt'IIYIII for o Special Permit for Grada/FID or,d a Crttig,I Arns Vuilnce In order to Jmpruve ln-nn,"" !'ow c:ond~IDns alon( I~ n:adi <>f M-v Cnlek Mtwnn•ppro,dmata lUYer Mlle U and (.9. n,. project would ruutt In tM remov,I of appro,lmotll!y lSZ c,,abk yards of~ R<llment fn>rn opprll.tmately 16:1 llnal feel of the MayO"Hk Channel and the rOfflOYIII of ~bstructtv<, ve1st1tlon lr .. d t:1N1ry ~u and wlHc,w b"ndlcs) from appn,xlm1H!y S40 Dne1l le!1 of n'ller diannel. The project b k,c:a~ In Ma-yValiey on th1 SOlM ildo of Moy Vanry load nurtne dtiu cl Newanle and Renlor1. The "°rtlon oftne pru)1i:t wttt,ln ,w,ton """uld OCCUf on• p,o,uf that b oppr,,d'""t•!y 3.75 -· The p,o;.ct sh• mntaln:I • C.lcJO,Y 3 w~and, and I C.a 2 ltrHffl (May Crtt~). A., m!tl11tlon for removlr11 11~lment and ve1e1otlon, 15 1 .. 1 of rl?l'rll/V-tllond yqotatlon ........id bt pl,,n19d on both ucla of Moy tr-11<. and also 011Wd1 of th. Oty limits. Th• pro}ect Ii e-prctecl to rommerg durina; th1 firrt l?l"Dffd fish wlrnfow 1fto!r reaiivtn1 the ~rmltl. Ernilronmontal (Sl:PAJ RrviN WU ,;,;,nd~d by Kini County u the lud lltflCY• PROJECT LOCATION! PUIUCN'PRDVAJ.S.: Wnt .ddt of 10th Ave Sf Ju1t M>uth of iU lnterH{:tion with SE Mry Valley .,.. N'PUCANT/PROJECT CONTACT PERSON: Ooug O,lr,, !Cini County Water I. I.Ind Resourtu Oivlskin; )OlSJoD.Jon Sla..ttliCQ; SutM. W1' pnOt; Eml: dou1.chSl@'klna;Ct>Uflty.rom OllfEll PERMJTS WHIOI MAY !IE REQUIRW, PUJUCHEAIUNG: US Nffl'/ Corps of Enllnters SKl'ion ,IO,t lndlwlual hfflllt; Compliance with Section 7 of the Endlf\1:1....i Spcdeo Act; Compll1nc1 with S.ctk>n 106 of tho N11lo111I Hirtoricl,I l'u>IMltlon it.ct;W1Jhlfl(lon ~partment of [a,lorv (D0(140l W1t1r a,.Uty Cenlflt1tlon; Wuhl,.ton DOE Nltio111I Pollutant Dl>ch1r,;1 Ellmln1t1on Symm Parmlt; Wuh\nJlon Oopar1m~nt of Fl1h I. Wlldllfe llydmdk l"n>}ec; AppnMlt Kine C.ounly O.•ri"l I Gn,d"'I Pem,it; Kin& County Critlal "'1!1 Alte111tlon· bctpl.lon; City DI R•nton 1'nrn,1I G111dU'\I i.bltMI . Puhllr bt1dnr \t1cnt11l•clY 1tbrdiilcd Im Aodl 16 i:QB b;fncc th• Brmon ttndm (qmlnrr 11 UXI pm In Renton Coundl O..ml>e11 on the 7th floor of Renton Oty Holl. Com,...nt, on the 1bo¥11 applkl!!or\ must be a1bmlttad ln ..mine to Ganlkl Wauer, AQod-l'llnne<, Department of CDmmunlty I. -nomk: Dn1lopment, 10S5 Solffll Gn,dy Way, R•nla'I, WA. 91057, by 5:00 p.m. oi, A.prll 4, 2013. T1'II mattor II "'"" tantatlwly schsdui.cl for I P"bllc htaril'\I on Ap,111', 2DU, at 1:00 p..m., Co....ctl Chom~fl,. Sn•nth Flour, lle-n ory H1U, lDSS Sou;th Gr,,dyWrf, 11,intDn. lfyaij 1n, lrtterutecl ffl 1ttendlrctho t..•rln&, p!HH a>fft.latnl Pllnnlrt 0111\sk>n ID tnoun, th1t the t, .. r1., h11 nD1 bun n,K-1,eduied ot (1.25) 430-72!2. lfcamment. c:annot be 1ubrnlttld In wrflml by the dltt lndaled ~ yoc, mrf rtlll 1ppe., JI tlw hurtnc ind pro,Mnt your tomm•ntJ Dn th• propos.l bef<>n, th• Heari"I Enmlrwer. lfrou how, questions 1bout this propoul, Dr wish ID be m.de 1 l>"rtv of rKDnl ond ,-Mr 1ddllbnll lnfc>nnatJon b<r' mal, pleo>1 CDntaCI: the P,ojfi! M1M1u. Anyone whG subrnlU wrttttn comments win 1111.omatlcllly become a p•rty of recar-d ind w1n be notlfled Dhny dedslon on this projea ~ you would like ti, ba m1de I party of record to race!,,e further lnformlllon on this propo>1d projoct, tomplel• fflb: form uid mum to: City ofRtnton, CEO, Plli"'*'l DMslon, lOSS SoulhGra.ti"Wrf, Renton, WA. 9IIOS7. Flit Nome / No.: t.\rf Crffl Dnln•I" Improvement P,0J1<1 / LUIJ.3-000187, SP, V•H NAME:---------------------------- MAIUNGADDIIUS! _____________ Clty/St>ite/Zip: ________ _ TilEPHONEttO~ ------------ DATE OF AP1'1.ICAT10N: NOTICE Of COMPLIT[ APPUCATll CERTIFICATION I~~ ,herebycertifythat 3 were posted in~ conspicuous places or nearby the n6,,hlh Date: 3 h~9o(3 STATE 6f: WA£H~GTON COUNTY OF KING ) ) ss ) februa,yU. 2013 m:h11,21lll I certify that I know or have satisfactory evid e nee that _ _,G~-:"-e '-'' ""'Jli.J. da._-1l,<1.w7 '"''"'' cs..rr..'C'-------- signed this instrument and acknowledged it to be his/her/their free and volunt_ary act for the uses and purposes mentioned in the instrument. Notary (Print): My appointment expires: EXHIBIT 34 •· CITY OF RENTON DEPARTMENT OF COMMUNTY & ECONOMIC DEVELOPMENT -PLANNING DIVISION AFFIDAVIT OF SERVICE BY MAILING On the 21st day of March, 2013, I deposited in the mails of the United States, a sealed envelope containing Acceptance Letter and Notice of Application documents. This information was sent to: Name Representing Doug Chin Contact/Applicant Stonegate HOA -Happy Longfellow Owner 300' Surrounding Property Owners See attached 'J.,,,A A -. -J_ '''''"""'''' (Signature of Sender): , LD \,./d;(,UJ:,{A/' ~,, GRA&..!11 1111 ;5° f· ''''"""''11 ~~ ,,. :' °<'" $~s\0N E-t!i,11 I~ \ STATE OF WASHINGTON . :i ff°/ o1Alli-"P.-\ ~ ) Ss ~ :o ~ u,~ ~ :;; :::u -·-~ ::. ,,.. ~ :: z::::: COUNTY OF KING ) :;; t ,o ," : O ~ ~ <P '111 LIB\. "':,f,.:;. E '/ :.>. ,,,,, 8~29 .. \.? 0 .E 11 ,-V )', '1•111 , ... ,,... ~ -I certify that I know or have satisfactory evidence that Stacy M. Tucker "', & 0 """ s'<'" J signed this instrument and acknowledged it to be his/her/their free and voluntary act for1Un1f 1u~e~fn~rposes \\\\\\\\\,~ mentioned in the instrument. Dated: 1(/111.UiJ JI :,013 I Notary Pu lie in and for the State of Washington Notary (Print): ___ -'~"--'A_,_._......._-.w .. Ces~ccf..:,'-S~"-'--------------- My appointment expires:· A + ,, q ., LJ l,C\] [...~ ,;<. / c;,_Q ''.">,:: -. •• -·1~· i . ; . ' ' ~ ... ~:CPrciject Name::··, May Creek Drainage Improvement Project ;;:,; .~~-k.,,~,. :·c ., . .._ .L, 1• :;;, ':_'!• -'l-~.-,·. ~ .. C,.!,l.':';';··~'l.\'.'1,/ ~:J>roject Number:· LUAB-000187, SP, V-H \... ,-., ... , . ' .. , ' BUTTAR BAUINDER S+ RASPHAL 6529 161ST PL SE . BELLEVUE, WA 98006 BYUS DEAN T III+KIERSTEN G 5602 NE 26TH ST RENTON, WA 98059 DALPAY PROPERTIES LLC PO BOX 2436 RENTON, WA 98059 SPIER ROBERT +MONIQUE BLOCH 5506 .NE 26TH ST RENTON, WA 98059 BONWELL JAMES L+JULIE P 9616 146TH AVE SE RENTON, WA 98056 CULBERTSON JASON ET AL 20211126TH PL SE KENT, WA 98031 CARLSON THERON A 2115 WHTIMAN AVE NE RENTON, WA 98059 MACKAY PAUL F JR+TAMMY L 5625 NE 26TH ST RENTON, WA 98059 DUNVEGAN TRUST EUNICE MCLEOD 10335 14TH AVE NW SEATTLE, WA 98177 KIM BARO 5500 NE 26TH ST RENTON, WA 98059 COLE GARY 9517 146TH AVE SE RENTON, WA 98059 BENSON EDWARD A+JAYME L 5416 NE 26TH ST RENTON, WA 98059 HORNE WILLIAM E LIVING TR HORNE WILLIAM E+MARY A TTEE 5604 NE 24TH ST RENTON, WA 98059 STONEGATE HOA PO BOX 2691 RENTON, WA 98059 LIEN HOLDINGS LLC 29928 PACIFIC HWY S FEDERAL WAY, WA 98003 YCK INC NO 4-1 IF LANE 46 YEN JIH ST TAIPEI 10553 TAIW, SALAS MELISSA C/0 WILLOUGHBY 5512 NE 26TH ST RENTON, WA 98059 10 / TEO PENG HENG+KITTY KITBING 11810 176TH AVE NE REDMOND, WA 98052 HOLMES ROBERT A SR+ TAMARA J 5320 NE 26TH ST RENTON, WA 98059 KUSUNOSE TARO 14524 SE MAY VALLEY RD NEWCASTLE, WA 98059 May Creek Drainage Improvement Project Notes None 193 0 1:2,319 0 97 NA0_ 1983_HARN_StatePlane_ Wash ington_ North _FIPS_ 4601 193 Feet City of Renton f) Finance & IT Division Legend Juri sdictio n Boundaries [1 Other (] City ol Renton Addresses D Parcels Overlay Districts O AutoMall A D Auto MallB [J Employment Area vaney r1 Ctty Center Sign Regulation Area Information Technology · GIS RentonMapSupport@Rentonwa .gov 4/9/2013 E3 Urt>lwl Oesig, District D Environment Designations O Natural II Shoreline High Intensity O Shoreline ISOiated High Intensity O Shoreline Residenbal o Urban Conselvancy D Jurisdictions Streams (Classified) -1 This map is a us~ Is f o, reference o EXHIBIT 35 May Creek Drainage Improvement Project Notes None 193 0 1:2,319 0 97 NA0 _ 1983_HARN_StatePlane_ Washington_ North_FIPS_ 4601 193 Feet CJtyof RenfOfl E) Finance & IT Division Legend Jurisd iction Boundaries [] ()the( [1 City of Renton Addresses D Parcels Overlay Districts 0 AutoMallA O AutoMallB a Employment Alea Valley ~ j City Center Sign Regulation Area lnfonnaUon Technology -GIS RantonMapSupport@Rentonwa gov 4/9/2013 B Urban Design O.strlcl D ~ Floodway • FEMA Flood Zones Environment Designations D Nall.ral • ShOreline High Intensity D Shonlltne Isolated High Intensity a Shoreline ReSldentlal D Urban Conservancy n .111n Thasmapis aL is for rererena EXHI BIT 36 PLAN REVIEW COMMEN. (LUA13-0_oo_1s_7=) ==-=-~lR~®Ibl~:~nu ~® PLAN ADDRESS: APPLICATION DATE: 02/12/2013 DESCRIPTION: Applicant requests Hearing Examiner approval for a Special Permit for Grade/Fill and a Critical Areas Variance in order to improve in.stream flow conditions along the reach of May Creek between approximate River Mile 4.3 and 4.9. The project would result in the removal of approximately 392 cubic yards of accumulated sediment from approximately 162 lineal feet of the May creek Channel, and the removal of obstructive vegetation (reed canary grass and willow branches) from approximately 540 lineal feet of r.iver channel. The project is located in May Valley on the south side of May Valley Road near the cities of Newcastle and Renton. The portion of the project within Renton would occur on a parcel that is approximately 3.75 acres. The project site contains a Category 3 wetland, and a Class 2 stream (May Creek). As mitigation for removing sediment and vegetation, 15 feet of riparian/wetland vegetation would be planted on both sides of May Creek, and also outside of the City limits. The project is expected to commence during the first approved fish window after receiving the permits. Environmental (SEPA) Review was conducted by King County as the lead agency. Reviewer Comments Kayren Kittrick Ph: 425·430·7299 email: kkittrick@rentonwa.gov Item Review Name: Engineering Review Comments: No comments from Plan Review. Storm Water Utility had no issues. April 11, 2013 Page 1 of 1 ---=-~= IGIF~~@JID 0 PLEASE INCLUDE THE Pr ~ NUMBER WHEN CALLING FOR PROPER;FILE IDENTIFICATION DATE OF APPLICATION: Filbruary 11, 2013 ~ NOTICE OF COMPUTt APPUCATION;'° Mardi 21,201) NOT!CE OF APPILICATION A Manu Appllcatlon hH bHnfll1d and 1cc1pt1d with tM D•1»rtm1nt ol Community & Economk Drnlopm1nt (CED)-Pl1nnln, Dl ... lslon of the City of Renton. The lo!lowl111 brl1llv deS<:rlbH th, 1ppllc1tlon and th1 n1te111rv Publlc Appronls. DATE OF NOTICE OF APPLICATION: M1n:h 21, 201l PROJECT N.AMl/NUMJEl'li M1yCtttk Dr1inll1e lm~m1nt ProjKI/ LUAU-000187, SP, V•H PR0JECT0ES0IIPTION: ,l,j)pllunt requests HHrinl h1mlnef lpptOVfl for I Sptd,.1 Pfrmll for Gr1de/Flll 1nd I Crl\\tlll .\rtaJ V1rillnce In onlH lO lml'f0'"1' ln-nrHm llow condlt1D1111lo111 the l'l!lch ol MIY Cretk Mtwttn 1ppro.im1te River Mlle 4.l 1Ni 4.9. The project woukl n,1ult In the n,mOVlt of 1ppro,lm1tely 392 tubic Yl'tb of accumulloted se<llm1nt from 1ppro•lm1te!y l62 ftnoal feet of the May =•k Ch1nnel, 1nd the n,mOYIII of obJtn.,ct"'- ve1et1Hon I reed canary 1r111 and willow branches) from 1ppro,lm1tely S-0 lln<11I feet of ,1,,.,, channt!I. The project II located In M1yV1II~ on the south 1ld1 of M1yV•lltV Ro1d neut he cit lei of Newgo•lle ,nd Renton. Th• porOon DI the project within Renton would occur on I p1rcel 1hat Es apprn•lmat1ly 3.75 acre,. The project ,tte cont1ln1 1 C.te1ory 3 Wi!tland, ind I Clan 2 strHm (M1y Creek). .o., mitigation for romovln1 sediment and ""l•l1Uon, lS fut of rlparl1n/w1tl1nd n1etatlon would be p~nted en both side• of Ml'f Crtek, 11\d 1lso outside of tf>e C~ limits. Tho project Is Hpected lo comm1nc1 durln1 the nrn 1ppro¥11d ft1h window 1fler rece,Vln1 the permits. Envlronmlnlll [SIM) Review wt, condvcted by Kln1 County u tr.e lead agency. ~ROJECT lOCATION: PUIIUC Al'f'flDVAlS: Won <Ide of 148th AIII! SE just south ol ~ lnllrHctlon with SE May Valley 1101d APPUCANT/PIIOJECTCONTACl PERSON: Dou1 Ct.I", K1na County w11 .. & land Resource$ DM,icn; 201 SJackson Stre•t•SDO; Seattle, WA~S104; Eml: dou1.ct,lntDklnJtoUnty.com OTHER PERMln WHICH MAY 8! REQUIRED: PU8UCHEAlllNG: US Army Corps of En1lnem Section 404 lndMdu1I Permit: Compll1nc1 with Section 7 of the End1n1er1d Species Act; Compliance with Section 106 of the N1tlo111I Historltal PrHeNltlon Act: w .. hlngton Department of EtOIOfY (DOE) 401 WatorQ1111lltyCtrtlftc1tlon: W1shlrcton DOE N1tlon.1I Pollutaot DEscharge Ellml11111Dn Sy1tom Ptrmtl; W1shlngton Dfopartffll!nl DI Fbh • W!ldll~ Hydr1ulk Projtct App,OY1!; Klrc CcU<lty O.arirC & Gr•dln1 P1rmtt; Kln1 County Crttk:;il ,.,.H Alter1t1on' [JCtpUon.: City ol Renton Ann1111I Gradi"I Ucen>e . PubHc bnrlnr 11 !rotlltnlv icbcdlllc!I tnr.&.ndl llii ZOU hftfotr me Renton Htulnr f>l>OJIQC( ti i·po pm In llenton Council Ch1mbo11 Dn tho 7th floor DI Renton Oty Hall. CDmm•nts on th, 1l>Dv11ppl!c1Uon mu1t 1>11ul,ml1ted ln wrlllfll lO G1r1ld Wn11r, Nlocl1t1 Plann•r, Dep1rtm1n1 of Community & Economic O.v1\opm1nt, 1055 South Grady Way, Renton, WAHD57, by 5:00 p.m.on April•, ZOU. Thi• m11terl1 al.., t,,ntitlnly ,<Mduled fora publlc Marini on April 16, ZOU, 11 1:00 p.m., Council Chambo11, SNenlh Floor, ll<!ntDn City Hal~ 1055 South GradyW.-,, Renton. If you""' ln\uuted irl 1tt1ndlfli tl>o r.euln1, !"nn contlct the Pl.mnlrc olvl,IDn to ""'u"' !hit the hearillg hn not been n,schedultd 1\ (4_2S)4J0.72B2. If comments uonot be wbmltttd In wrltlnf: by the date lndoted above, you may Jtll! 1ppHr 11 the M1rl111 and present your commenu on !he prt>pD .. I ti.ID'* thl Hearlfli E•1mlner. II you"""• qwstloru about this pmpo .. ~ ot wish lo bt n11dt 1 party of n,a,nl 1nd r«elve 1ddltlo111l lnform1Hon bym11l, 1"11sa contact the Project M1nq:er. Anyono ..t,o 1ubm1U written commenu wlU 1u\omatluolly ti.come • p1rry of ,ecocd Ind wtll bl ncllfltd of 1ny decision ""1h11 pro)ed II you would Ilk• to be m1dt I party of record to retelve further ln!onnatlon on th!J pro?O"'d projl!ct, a,mplete this form 11\d return to: City ofRen\Cn, CEO, Pl1nnlna DM1lon, 1055 South G,1~v Way, ll<!nton, WA 98057. File Name/No.: Ml\' Crerk Or1ln1Je Improvement ProJtct/ Ll.lAH-000187, SP, V·K NAME:----------------------------- MAlllNGADORBS: _____________ Clty/51111/Zlp: ________ _ TElEPHONENO: ------------ CERTIFICATION I~ ~ , hereby certify that 3 were posted in ·3C_;;on;;ia:;ous places or nearby the .,.,:,4.,.._ Date:.3,k/-~3 Signed: STATE 6f: WA~GTON ss COUNTY OF KING I certify that I know or have satisfactory evidence that GecrJd t,7 0 «·« signed this instrument and acknowledged it to be his/her/their free and voluntary act for the uses and purposes mentioned in the instrument. 1d ,A ~q 13 Notary Public in and for the State of Washington Notary (Print):_...;/{.;.:-:.....:.:11a.----'"G'-'-r.""e4?""""1£1..-_____ _ My appointment expires:_-"'4,,"""e{f-.l"'""s±,._,_.....:a,;;o....i..~--"";;,q~bi,,i.._ _____ _ . CITY OF RENTON DEPARTMENT OF COMMUNTY & ECONOMIC DEVELOPMENT -PLANNING DIVISION AFFIDAVIT OF SERVICE BY MAILING On the 21st day of March, 2013, I deposited in the mails of the United States, a sealed envelope containing Acceptance Letter and Notice of Application documents. This information was sent to: Name Representing Doug Chin Contact/ Applicant Stonegate HOA -Happy Longfellow Owner 300' Surrounding Property Owners See attached (Signature of Sender): '''''"'"""'' ...,)!fd.~U.#~LJ:..L~~~d.J.~'.f::.---------,£'"':::"":,."~RAD-,,,,, .::,. . !I,,'""'"'~~ ,,,,. ff '),,.• $'1\\0N tt.!:1111 ~ -.,..-~~ ifP.(, ~ \ :: =K 0 1Afi>-"'\ ~ ) SS 3 fo ~ '"\ ~ ., ... u -. .. :: z ~ COUNTY OF KING ) ~ .ft\ "'IIB"'" j O E STATE OF WASHINGTON ~ ..... ,,, 8 'I'?)" I.. -1 .-,,,, .. 29-; <, E ,, "9 >....-'•1,h i..,,,,.... ~ - I certify that I know or have satisfactory ev_idence that Stacy M. Tucker t,,,, · (::' o;'"' ,..,,+-"/ signed this instrument and acknowledged ,t to be h1s/her/the1r free and voluntary act for l4nff,H~~t~,Q-_~rposes mentioned in the instrument. Dated: lf/)aW2 JI JOl3 I Notary Pulic in and for the State of Washington Notary (Print): ___ ..!.Uc..A!2,_, ..1G.z-1..,calo=:s.llc.._ ____________ _ My appointment expires:· A 1,ti\ "-rt d-q 1 ao l.J Project Name: May Creek Drainage Improvement Project · Project Number: · LUAB-000187, SP, V-H • BUTIAR BAUJNDER S+ RASPHAL 6529 161ST PL SE BELLEVUE, WA 98006 BYUS DEAN T Jil+KIERSTEN G 5602 NE 26TH ST RENTON, WA 98059 DALPAY PROPERTIES LLC PO BOX 2436 RENTON, WA 98059 SPIER ROBERT +MONIQUE BLOCH 5506 NE 26TH ST RENTON, WA 98059 BONWELL JAMES L+JULIE P 9616 146TH AVE SE RENTON, WA 98056 CULBERTSON JASON ET AL 20211 126TH PL SE KENT, WA 98031 CARLSON THERON A 2115 WHTIMAN AVE NE RENTON, WA 98059 MACKAY PAUL F JR+TAMMY L 5625 NE 26TH ST RENTON, WA 98059 DUNVEGAN TRUST EUNICE MCLEOD 10335 14TH AVE NW SEATILE, WA 98177 KIM BARO 5500 NE 26TH ST RENTON, WA 98059 COLE GARY 9517 146TH AVE SE RENTON, WA 98059 BENSON EDWARD A+JAYME L 5416 NE 26TH ST RENTON, WA 98059 HORNE WILLIAM E LIVING TR HORNE WILLIAM E+MARY A TIEE 5604 NE 24TH ST RENTON, WA 98059 STONEGATE HOA PO BOX 2691 RENTON, WA 98059 LIEN HOLDINGS LLC 29928 PACIFIC HWY S FEDERAL WAY, WA 98003 YCKINC NO 4-1 IF LANE 46 YEN JIH ST TAIPEI 10553 TAIW, SALAS MELISSA C/0 WILLOUGHBY 5512 NE 26TH ST RENTON, WA 98059 i87 TEO PENG HENG+KITTY KITBING 11810 176TH AVE NE REDMOND, WA 98052 HOLMES ROBERT A SR+TAMARA J 5320 NE 26TH ST RENTON, WA 98059 KUSUNOSE TARO 14524 SE MAY VALLEY RD NEWCASTLE, WA 98059 NOTICE OF APPLICATION A Master Application has beel1 filed and accepted with the Department of Community & Economic Development (CED) -Plannlng Division of the City of Renton. The following briefly describes the application and the necessary Public Approvals. DATE OF NOTICE OF APPLICATION: March 21, 2013 PROJECT NAME/NUMBER: May Creek Drainage Improvement Project/ LUA13-000187, SP, V-H PROJECT DESCRIPTION: Applicant requests Hearing Examiner approval for a Special Permit for Grade/Fill and a Critical Areas Variance in order to improve in-stream flow conditions along the reach of May Creek between approximate River Mile 4.3 and 4.9. The project would result in the removal of approximately 392 cubic yards of accumulated sediment from approximately 162 lineal feet of the May Creek Channel, and the removal of obstructive vegetation (reed canary grass and willow branches) from approximately 540 lineal feet of river channel. The project is located in May Valley on the south side of May Valley Road near the cities of Newcastle and Renton. The portion of the project within Renton would occur on a parcel that is approximately 3.75 acres. The project site contains a Category 3 wetland, and a Class 2 stream {May Creek). As mitigation for removing sediment and vegetation, 15 feet of riparian/wetland vegetation wou(d be planted on both sides of May Creek, and also outside of the City limits. The project is expected to commence during the first approved fish window after receiving the permits. Environmental (SEPA) ~eview was conducted by King County as the lead agency. PROJECT LOCATION: PUBLIC APPROVALS: APPLICANT/PROJECT CONTACT PERSON: OTHER PERMITS WHICH MAY BE REQUIRED: PUBLIC HEARING: West side of 148th Ave SE just south of its intersection with SE May Valley Road Hearing Examiner Special Permit and Critical Areas Variance Review Doug Chin, King County Water & Land Resources Division; 201 S Jackson Street #600; Seattle, WA 98104; Eml: doug.chin@kingcounty.com US Army Corps of Engineers Section 404 Individual Permit; Compliance with Section 7 of the Endangered Species Act; Compliance with Section 106 of the National Historical Preservation Act; Washington Department of Ecology (DOE) 401 Water Quality Certification; Washington DOE NatiOnal Pollutant Discharge Elimination System Permit; Washington Department of Fish & Wildlife Hydraulic Project Approval; King County Clearing & Grading Permit; King County Critical Area Alteration Exception; City of Renton Annual Grading License Public hearing is tentatively scheduled for April 16, 2013 before the Renton Hearing Examiner at 1:00 p.m., in Renton Council Chambers on the 7th floor of Renton City Hall. Comments on the above application must be submitted in writing to Gerald Wasser, Associate Planner, Department of Community & Economic Development, 1055 South Grady Way, Renton, WA 98057, by 5:00 p.m. on April 4, 2013. This matter Is also tentatlvely scheduled for a public hearing on April 16, 2013, at 1:00 p.m., Councll Chambers, Seventh Floor, Renton City Hall, 1055 South Grady Way, Renton. If you are interested in attending the hearing, please contact the Planning Division to ensure that the hearing has not been rescheduled at (4.25) 430-7282. If comments cannot be submitted in writing by the date indicated above, you may still appear at the hearing and present your comments on the proposal before the Hearing Examiner. If you have questions about this proposal, or wish to be made . a party of record and receive additional information by mail, please contact the Project Manager. Anyone who submits written comments will automatically become a party of record and will be notified of any decision on this project If you would like to be made a party of record to receive further information on this proposed project, complete this form and return to: City of Renton, CED, Planning Division, 1055 South Grady Way, Renton, WA 98057. File Name/ No.: May Creek Drainage Improvement Project/ LUA13-0D0187, SP, V-H NAME: MAIUNG ADDRESS: ________________ City/State/Zip: __________ _ TELEPHONE NO.: -------------- PLEASE INCLUDE THE PROJECT NUMBER WHEN CALLING FOR PROPER FILE IDENTIFICATION DATE OF APPLICATION: February 12, 2013 NOTICE OF COMPLETE APPLICATION: March 21, 2013 Denis Law May_or· ·. :· De.partineni of Community and Eqmcimic peveiopment. . . . . . . . . . CE."Chip"Viricent, Administrator. March 21, 2013 · Doug Chiri.• · Ki rig County Water & Land Resources Division· 201 s·J~ckson Stre.et #600 ·. · · .. · Seattl~. WA 98104' Subject: Notice of Complete ~pplication - .. · .. MayCree~Drainage Improvement Project, LUA13-000187, SP, V-H .· Dear Mr. Chin:. :-;- . The Planning Division ofthe city of R_enton has determined thatthe subject application is i:omplete according to submittalrequiremerits and, therefore, is a~cepted for.review. ' . . ' . ' ' ' . ' . ," .. ·. You ~ill be notlfied if any additional information is r~quired to continue processing you~ application; In addition, this matte~ is tentatively scheduled for a Public Hearing oil April '.iG; 2013 <)t 1:00 p,m,,,C6undl Chambers; Seventh·Floor, Renton CityHall,1055 South. Grady Way; Renton. The appliGantor representative(s) of the applicant are requi~ed 1:0 · . be present at the publi~ hearing. A copy of the staff report wiU be·mailec(to you priorto · the scheduled -Ii.earing.·· . Please contact [Ile at (42S) 430-73~2 if you ha~e any questions:.· .. · . ' . . . . . . . . . ' ._ : . . . '. ·. . · Sin~e(el . ' cc:.. _Stonegate HOA.· Happy Longfellow/ Owner(s) , : -' . I AITACIIMENT A .. .. ··--- s..cd@a.-.ro. p,r.alid l'm)>acu oflhlsPNl!ccr. a "u...i..ana\ylh'\ ;( 1• o,qlllrcd. CO..,ictlM ol"&,c!fDII 8 of lhb Ihm by• qlsl<..t i,u,lo,!low cogln<,:rb • ..,,l;i!o,\ ol'lllo &m.ccofllmpornL - Q l<J10lr"l"lnidlllrlllolbl!Gwlogm"""' _ • 0 ,..,._...., ,.. .. ~slnJc!D<Oivlll101ll~tl,o llo>M1~oofl>olprlltofdic""'1ciun,. Q ·1'oa...Spl«lblulclada1uys=mwlllulOslgoiD:ao1l~IO no.... - CJ Colslnt .. A•zone a Sbnllowlloofllos,-(AOI/Ul,...,) ... lllijocc,>t10atlva/nom-('"PI'°"') Cl J,aell«liw llo1lr oroo. (CJpla~ a ~l""i:CCI I= wllllla oiiyiiiiiillc obadow.{mq,lain} Cl Oli>O<(e,q>laid) --------·---.. -·- '/ S.cUon B King County Flood Hazard Ccrtifice.tion I hnvocomlclctcdlllolm>ldsi,:pcoce,,1edoo pauel nS3033C066PF o!lho.FloodlDS1JrtUe8"'6y rorKlng O>uoty, dated Mar 16, 1995, and die '"pponillg documcatation. l bavc also =n:hcd for aa1I consldcr<d all olho, available ialo111111Uon incliicfiD&: Pidu,wmy Flood lnsunmoc Rote Mflls {l'-FIRMo); Prelimirery Flood Im= Sbutiea; Dr.di flood bouoda,ywork map ud amob!Od tecbnlcal RporU; Critiw...., iq,ons p<q,aml in acco,dmloo with PEMJ.. ,w,d,ud:s set fonl,.11144 C.F.R. Pait'6S mid comisltlll wl1h Ibo KiOf: Coo111y Sur1llco WoJcr Desig/1 Mamlal pR>vi>ias for. lloodpl,m ..,.1,.;, SCI fcnh ,1 =<ioa •U.2; 1'!tlor~!l!!-iiao!! (LOMAs); . Lc(terofMJ~~-Cballoclmigrtdon """° maps and s!Udi,o;~ilaod ham~ and Site topog,:uphyand 81\llllld clmllions. All ,o~ an, clwly ldclllificd In d>c ..uaclwl ~ I» oddidon, 1 have c:r<al<id DQW dl'8 \Vhuoexisliog ,ouoxure 111>1 sur.iclont lo....,. complianto, and Ibo aUaduld report clearly docomc,1ts 111y mcd,ocls andmsumptiOSIS. I ccllify that tbc ouacbed r<dldiall dala suppons Ibo filc1 lh1t lllo pt0joot JlllDICd obovo will,.... King Cauuty ~menu for protccDDD of l!oodph>in "°"B" olld Ooodplain coove~. as ,e1 !anh in K.iog Couoiy Code Tille 21A. Coo:'4'1iaoce is acluc:ved11.s: described below. · .A.btlltd ll p,ll snppcr1 ditz :ad akllladons. By------+------ ])1)1!$~ Exhibit 1: Exhibit 2: Exhibit 3: Exhibit 4: Exhibit 5: Exhibit 6: Exhibit 7: Exhibit 8: Exhibit 9: Exhibit 10: Exhibit 11: Exhibit 12: Exhibit 13: Exhibit 14: Exhibit 15: Exhibit 16: Exhibit 17: Exhibit 18: Exhibit 19: Staff Report, dated April 16, 2013 Aerial Photo, Showing Project Site Vicinity Map and Index (Sheet 1 of 20} Neighborhood Detail Map (Sheet 1 of 1) Topography Map (Sheet 1 of 1) Existing Conditions, Sheet Key, Legend, Construction Notes (Sheet 4 of 20} Site Plan (Sheet 1 of 1) Landscaping Plan (Sheet 1 of 1) Temporary Erosion and Sediment Control Plan, Legend (Sheet 5 of 20} Sediment Disposal and Turbid Water Dispersion Locations (Sheet 7 of 20) Plan and Profile, STA 0+00 to STA8+00 (Sheet 10 of 20} King County Mitigated Determination of Non-Significance (Issue Date September 8, 2010} Stream and Wetland Impact Analysis and Mitigation Plan (King County Road Services Division and King County Water and Land Resources Division, Revised September 2011} Wetland Delineation Report (King County Road Services Division, Environmental Unit) March 10, 2010 City of Renton Wetland Rating Addendum to Wetland Delineation Report Dated March 10, 2010 (November 17, 2010} Baseline Stream Conditions (Revised December 2, 2010} May Creek Sediment Transport Study Report (Anchor QEA, LLC, June 2009} May Creek Erosion Stabilization Draft Report/May Creek Sediment Transport Study Phase 3 (Anchor QEA, LLC, January 2010} Hydraulic And Hydrologic Analysis (King County Department of Natural Resources and Parks, Water and Land Resources Division, Science Section, December 17, 2010} - Exhibit 20: Exhibit 21: Exhibit 22: Exhibit 23: Exhibit 24: Exhibit 25: Biological Evaluation Report for: Chinook Salmon and Steelhead Trout as protected under the Endangered Species Act (King County Road Services Division, February 2011) May Creek Drainage Improvement Project: SE May Valley Road and 1481h Avenue SE -Sediment Assessment (King County Road Services Division, Environmental Unit, February 9, 2011) May Creek Drainage Improvement Project (9A1205) Post-Construction Erosion Monitoring Plan -Downstream of 1481 h Avenue SE (King County Road Services Division, Engineering Services Section, August 4, 2011) Construction Water Quality Protection and Monitoring Plan (King County, Revised September 7, 2011} Correspondence between the Department of Ecology and King County Including: o Exhibit 24-A: Internal DOE memo from Patricia Olson to Rebekah Padgett, August 15, 2011; o Exhibit 24-B: Letter to Doug Chin from Washington Department of Ecology, RE: US Army Corps of Engineers, Status of Application for Section 401 Water Quality Certification and Coastal Zone Management Consistency, dated September 1, 2011; o Exhibit 24-C: Letter from Rebekah Padgett, DOE to Doug Chin, King County, September 16, 2011; o Exhibit 24-D: Letter from Doug Chin, King County to Rebekah Padgett, DOE, February 9, 2012; o Exhibit 24-E: Internal memo from Jeff Burkey, Hydrologist, King County Water and Land Resources Division, to Doug Chin, Water and Land Resources, dated January 11, 2012; o Exhibit 24-F: Internal Memo from Jeff Burkey, Hydrologist, King County Water and Land Resources Division, to Doug Chin, Water and Land Resources Division, dated December 14, 2011; o Exhibit 24-G: Internal DOE memo from Patricia Olson to Rebekah Padgett, May 22, 2012; o Exhibit 24-H: Letter from Eric Stockdale, DOE to Doug Chin, King County, June 14, 2012; o Exhibit 24-1: Internal Memo from Julia Turney, Geologist, King County Environmental Unit, Road Services Division, Department of Transportation, to Doug Chin, King County, dated August 1, 2012; Washington Department of Ecology, Water Quality Certification Order #9352 for USACOE Public Notice #NWS-2010-158, January 8, 2013 Exhibit 26: Exhibit 27: Exhibit 28: Exhibit 29: Exhibit 30: Exhibit 31: Exhibit 32: Exhibit 33: Exhibit 34: Exhibit 35: Exhibit 36: King County Clearing and Grading Permit (L10CG223), Issued November 14, 2012 NOAA/NMFS (Tracking No. 2011/00601) Endangered Species Act Section 7 Informal Consultation, March 10, 2011 WDFW Hydraulic Project Approval, (Control Number: 123184-2, September 26, 2011) Rehabilitation Plan: Wetland and Riparian Mitigation (Sheet 1 of 7) Rehabilitation Plan: Planting Tables and Notes (Sheet 6 of 7) LUAll-065 Hearing Examiner Final Decision (Issued November 8, 2011) LUAll-065 Hearing Examiner Decision on Reconsideration (Issued January 9, 2012) ' Master Application Proof of Posting & Mailing Aerial Photo showing wetland, streams Aerial Photo showing regulated flood plain - [Nl]@W ~[?@@~ @[?cIDDmJ@~® D Dlil]~[?@W®ITCru®mJU [¥)[?@]@~'U [lJlJA13=000187p SPP V-Hl ?lUlb~Hc !Hlearong .Jleronifer Henning, CUID"D"ent l?lanD1long ManageD" April 16, 2013 - ~ y ' ·~~ o~,, u~ • ·~~ 6l~, • - [IDcro@{r W@~~CFD[W11D@[ru Subject Site: 0 Project is within City of Renton and unincorporated King County 0 Site is 3. 75 acres, area of impact in Renton is 36,600 s.f. (0.84 ac) 0 R-1 Zone RENTON AIIF.AD OF THF. CURVE • " rn3cro®u [Q)®~~croCID\£D@O'i) ~ Critical Areas Include: . 0 May Creek, Class 2 Stream (100-foot buffer) 0 Green's Creek or Green Stream, Class 4 Stream {35-foot buffer) ~ Category 3 Wetland (25-foot buffer) 0 Regulated Flood Plain = ~, .,. '-.· ~ ... #. ·,,., ~· ~4 <mEf$, ~-.,~.:· t,...--... RENTON AUE.AO OF THE CURVJ~ ~:Ji ! Q- •."1;;,".·3 '.~ .... ..t._ ..... ; • J -'• \~?.~· --~- .-~~y ~~ Q~ ~ ~~~ ~~NrfQJ " --- LYONS AVE N.E. / I ,. 1:1 •• ' i . i 0 = w d • > 0 "' > " V, =• 0 ,-;, .,, .., ti) ~ 'v = (') I» C: 1! :s " I t. :• i l < ! J j :'!": I u. -.. I I m .. ; 1 I ,, )( ' 11 I ' ':J' -· ' O" l If, =• ., ,-;, • I, ....n i t ,, - t lh, •• • > ~ -"' m > " 0 z .,, .., i-3 ~ " 0 C: " < z :!"l ----- I I _, ., 1/• I ·,1 I f,f I I ' t :s , ' t r.'t t I I t:: I f 0 ~ :s fi. Ill n gJ "g =• :J C7Q "g = I» ::I -m )( =r =• g" -· ,-0, co - • ·- 0 0 0 0 0 0 0 0 ~[jo@{f @@~~[jo~~D@[ru Accumulated sediment that results in upstream flooding would be removed. 392 cubic yards of material over 160 lineal feet of May Creek. Obstructive vegetation would be removed from 540 lineal feet. Mitigation includes restoration with native vegetation, placement of large woody debris, construction of off-:channel alcoves. A split-rail fence and signage would be installed. In-water work would occur during the fish window (June 16- September 15). Special Permit for Grade & Fill required by City due to substantial · public/agency interest and concern. Critical Areas Variance is needed in order to disturb the wetland and stream. RENTON AHEAD OF THE CURVE @cro@tr @@~~cro~\1o@D'u ~@D'u\10 0 Ottlrneir Age1n1ccv l?eirmD'lts Needlecdl: 0 U.S. Army Corps of Engineers Section 404 Individual Permit ~ Compliance with Section 7 of the Endangered Species Act ~ Compliance with Section 106 of the National Historic Preservation Act 0 Washington Department of Ecology 401 Water Quality Certification 0 Washington Department of Ecology National Pollutant Discharge Elimination System Permit ~ King County DDES Clearing and Grading Permit 0 Washington Department of Fish & Wildlife Hydraulic Permit Approval RENTON Al-lf:.AO OF Tl-IF. CURVE rfilcro®u @®~CGcro[W~o@Cru ~@[ru~D 0 On September 8, 2010, King County Water and Land Resources Division issued a DNS-M which included 5 mitigation measures: 0 Diverting stream flow around the work area; conducting in water work during summer low flow; having a biologist present. 0 Utilizing existing access roads; allowing direct stream access only where vegetation disturbance can be minimized. 0 Add approximately 1.3 acres of wetland and riparian vegetation along May Creek (15 feet on each side of May Creek from 14gth SE upstream to the end of the project). Install fencing to protect plantings from livestock. 0 Enhance 3. 75 acres of wetland on west side of 14gth Ave SE by removing reed canary grass and planting native wetland vegetation. Excavate off-channel alcoves along May Creek; add large woody debris and stream bed gravel to enhance wetland fish habitat. 0 Restore fish habitat and natural stream processes at the confluence of Long Marsh Creek and May Creek or at a similar location in the project vicinity unless otherwise approved by permitting agencies. AIIEAO OF THf. CURVE ,;;c.y (j -~·~ ~ b~ ~ ~~~ ~~N~Q' RENTON ~LID®~D@D ®CF@@® ~ CS'oDD ~@Cf'mmo~ &Uu@DW~D~ 0 Suze caJITTJd lo<ecaJttD(0)fi'i1 (O)~ ttlru(e A<etta~atty~ 0 Dredge 392 cubic yards of in-stream gravel 0 Remove flow obstructing vegetation 0 Site is between May Creek River Mile 4.3 and 4.9 0 Sediment would be placed in drying areas to the east of 148th Ave SE RENTON AIIE.AD OF THF. CURVE ~[W@~o@:l0 @U'@:l@J@ f£ [f'oOD ~®U'ITDuo'Q &Uu@DW~D~ 0 liraffn«:: Vo~lUJmes aiirutdJ !Paitttt<eirrrus~ 0 Work would begin during Summer 2013 or 2014. 0 Day/Hours of Construction: Monday-Friday, 7 am -7 pm. 0 Sediment would be moved to drying areas (east side of 148th Ave SE). 0 Dried material would be incorporated into adjacent pasturelands outside the floodplain and sensitive areas. 0 Unused material would be hauled to approved off-site location. RENTON AHEAD Of THE. CURVE ~C0@~o®D @U'cID@@ ~ CS'oOO [F)@U'mmo~ £[fi)cIDDW~D~ 0 Scrreern1ong 0 lai!lilds;ccapa1T11g 0 tFe1T11ccang &. Setbacks~ 0 No screening or fencing is required by the City of Renton Development Standards. 0 Applicant proposes to install a split rail fence to protect the enhanced riparian & wetland habitat. RENTON AHEAD OF THE CURVE ~y ' ·~'~ C?~ u~ ¢, ¢,~~ ~~Ni\'Q J "' --- ~CQ}®~D@D ®Cf@@® ~. CS'oDD [¥)@[fDVi)0~ &eru@D~~D~ 0 UrrnsHghtliraess 0 N«:»HS(E?0 lDllJJstt~ 0 Temporary disturbance is anticipated, however areas disturbed will be restored. 0 0 0 During construction, equipment operation would temporarily increase noise levels in the vicinity, however construction noise is not anticipated to be higher than airport operations noise. Material transported will be moist. If dust control is needed, it would be provided using a method approved in the KCSWDM. Rock and/or gravel construction entrances will aid in reducing mud on streets and dust impacts. "y O' u~ ~ RENTON ·~~ ~ ~ :!I.NS~ ~~N<\'Q) AHEAD OJ-" THE CURVI! ~~@~o®O @U'®@'.J@ ~ CSoOO [1)@[]'ITiJiJD~ &Cfu®DW~D~ 0 SlLBirfate Warlteir~ 0 Sediment and Erosion Control measures would be implemented. 0 May Creek will be diverted around the work area to minimize downstream impacts. 0 In-Steam work would occur during low flow periods in Summer. 0 Silt fences, coir logs and other best management practices would be used to keep sediment out of critical areas. 0 Equipment used to remove sediment would operate from stream banks. 0 Sediment removal will occur in sections, beginning upstream. RENTON AHEAO OF THF. CURVE ~[W@CI;D@D @0"©1@@ ~ CS'oDD ~@D"DlruD~ &Dll@DW~D~ 0 Sl!Jrr~a1te Wai'iterr~ 0 Sediment will be placed in sediment drying areas east of 148th Ave SE. ~ Cofferdams and sump pumps would be used to ensure water quality at the introduction of water flow to the channel. 0 Turbid water would be pumped out at the downstream end and discharged to temporary water dispersion areas. RENTON AIIEAO OF TJ-IF. CURVE ~C§)®~o@O @[?@@® ~ ~oOO [¥)@[?Cfim0~ &@@O~~o~ 0 !RelUlse (Q)f Sate~ 0 Site is vacant and zoned for low density residential. No change of use would occur as a result of the project. 0 lrransferabiHty ©i Spetaai~ ?eirmst~ 0 This is a one-time project, and the permit is issued for the site. 0 rPerrmot rExpuirate(Q)n~ 0 This is a one-time project expected for summer and early fall of 2013 or 2014. The permit is valid for 6 months and the applicant is requesting an 18-month approval to allow for work during the approved fish window (June 16 - September 15). ~ 0 6~4 9~9 ~.~ .. ~.!£.~ ~Q~ ~cro't1o~@l0 &er@@~ WcillCfD@llru~@ 0 Variance from RMC4-3-0l50l:IE.l: "l?rotection of Crotoca~ Areas: Crotoca~ areas alnldl ailnlv aissocoaitedl lb1U1ffers s~a~~ lbe ;ai~(Q)odledl, ailnldl 1U11nldlost1U1rlbed ••. 11 0 Disturbance of the wetland for flood control purposes is not exempted in Code. RENTON AHEAD OF TIIF. CURVlt "'y O' :~~ ~ u~ ~ ~~~ ~~1'.T,rQ) "~ ~[fo'Qo~tIDD £[r®tfil~ WtID[r'DtfilD'iJ~® 0 IP>ll.Blbloc IHlea~fch, Sa1feit'V & We~farre: 0 Project would increase channel flow to alleviate the duration of localized flooding. Project would not likely create an increase in downstream bank erosion or downstream flooding. 0 <Conformance with (C(Q)m~rrehensive IP>~airo andl Adoptedl i?lUJ lb>~ oc i?rr(Q)grra ms/1?(0)~ acnes: 0 Proposal would meet Comprehensive Plan policies regarding flood protection (EN-1); minimization of erosion and sedimentation (EN-2); and the naturalization of degraded streams, creeks, and banks (EN-4). 0 May Creek Basin Plan RENTON AI-IEAO OF THF. CURVE ~y ' ·~'), ~4 b~ ¢,. ¢,~~ ~~N1:Q) ~croUD~@D £IT'®@~ ~©}[f'O©}[n)~@ 0 IEstab~os~ecdljl ~dell"iltoioecdl i?ll.Olbl~oc Needs: 0 Project would result in flood protection upstream. 0 N(O) l?iracicocca~ A~teirll"ilaici~e [E)(osics ic(O) Meet Needs: ~ Four other alternatives were examined and the proposal was selected as the most practical. RENTON AHEAD OF THE CURVE ~y . ·~·~ C?-& b~ ~ ~~~ 6:~N<fQ J "' """"-' • . ~crorQo~cIDD &cr@cID~ 'WcIDcrocIDrru~@ 0 lllfi"llaivoidlaib~e ~m[P)ai«:its aire <Com[P)efi"llsaite(d] for wittlhl A[P)proproaite & Afformaiitove Meaisurres: ~ Construction equipment would use existing roads; 0 Rubber Tired or tracked vehicles would be used; 0 TE&SC and BM P's would prevent sediment from reaching stream and wetland areas 0 Disturbed areas would be restored with native vegetation 0 Weed barrier fabric would be used to suppress reed canary grass. AHEAD OF TIIF. CURVE ~y ' ·~')c C?~ b~~ ~~~ ~~N~QJ RENTON '• . ~croUD~@D &CF®@~ 'W@CFD@Cru~® 0 Ull'\la~oodlalbJ~e ~m[P)aictts aire Ccompelnlsattedl foir wotrni AIP)pli"O[P)li"Dal'lte & Affoirma'lto~e MeaSl\Jlli"teS {tt:Olnlitilnluedl): 0 In-water work would be conducted during summer low flow construction work window (June 16 through September 15). 0 Stream would be diverted during in-stream work. 0 In-stream vegetation would be removed by hand. 0 Turbidity curtain would be installed to protect stream. RENTON AHEAD OF THE CURVE t '. • ~[FO~D~@D &CF®@~ W@CFD@ITiJ~® 0 No Neit loss of AIT'eai, Va~l\JJe (QJIT' IFl\JJllilCitoollil of 'ltlhle ~egu~arfcedl We'lt~aillild CIT' S'lt!T'eaim Wol\JJ~d Oc«:l\JJIT': ~ Compensatory mitigation would offset impacts of sediment and vegetation removal. 0 In-stream alcoves would be constructed. 0 Native plants would be installed. 0 Monitoring would be required per RMC. RENTON AIIEAD OF TIIE CURVE • • ~cro\£D~@D &cr@@~ 'WcIDU'D©)[ru~@ 0 l?rroposedl Actto~o'ltoes Wu~~ Not Jeo!P)airr<dloie IErro<dlarrogerre<dJJI lhrea'lterile<dl orr Serroso'lto~e Si!P)e«:oes: 0 Project may affect but in not likely to adversely affect Chinook salmon and steelhead trout. 0 Project would have no effect on bull trout. RENTON AHEAD OF TIIF. CURVE ~y (j ·~')-~ b~ ~ ~~~ ~~NrtO. J ""--'- t' .. • ') ~croQo~cIDD &cr@©J~ WcIDCFO@J[ru~@ 0 !Prr(Q)fp)lOJSedl A«:'ltovoitoes WO~~ [l'O(Q)'\t (allJJse Sognifica111r!t IDegrraidlaritoorro of GrrollJJ0'1Hdlwa'lterr (O)rr SllJJrrfaice Waiiterr Quality: 0 BM P's would be employed to protect surface and groundwater quality. 0 Individual 401 Water-Quality Certification has been issued by DOE. 0 A.fPfPrr(Q)va~ lOlf 'ltihle Varroarroce os 'lthe MirroomllJJm Needled!: 0 The removal of vegetation and restoration with natives is the minimum needed to accomplish flood protection. RENTON AHEAD OF THE CURVE J# .. • ; ~tro~o~cIDO &[Y@cID~ W©l[YDcID[ru~@ 0 l?irojposedl Vaiiroaif/'\lce us Based Of/'\l Collilsiderrai'ltoorni of Bes'lt A'\fai~alb~e ScoeD"ilce IPE!IT' WAC 365-195-905: 0 Best Available Science was used in the preparation of studies and reports for the design, evaluation, and mitigation of project impacts in conformance with WAC 365- 195-905. RENTON AHEAD OF THE CURVE 0~ ~ ,·~~y ~~ ~~~~ ~~N'£Q) 1111 • ._. • 00.@~@DliiJ DliiJ@ @©J ©lU o@@ Staff 11'ecommendls aiiPJ[P)l1'0Vai of tthe Specoai Gi1'adle and! !Foll l?el1'mott arodl the (11"ottoca! A11'eas Varriance fol1' May C11"eek Drraiinage ~miPJl1'0vementt IP'11'ojectt, IFo!e No. Ul.JJA13-000181, SP, V-11--0 subljectt tto 'lt'w o co ll"'i)(CH tt o on s : 1. Compliance with the mitigation measures contained in the Mitigated Determination of Non-Significance, issued by King County Water and Land Resources Division, Department of Natural Resources and Parks, dated September 8, 2010. 2. The applicant shall also comply with the Stream and Wetland Impact Analysis and Mitigation Plan throughout and following construction. RENTON AHEAll OF Tl-IF. CURVE : . I I I .. ·.· .. · ..... . ''" 1--. Changes Sftnce JLaist Heairftng I L __ I I I ' i ' I L (Changes Since Last Hearing 0 October 18 and November 14, 15, 2011: Meetings with Ecology ~ February 2012: Documentation Provided to Ecology in Response to Patricia Olson's August 2011 Memorandum (IEltlhibut 24ilD>}. 0 April 2, 2012: Field Meeting Downstream with Agencies and Owners 0 May 22, 2012: Analysis by Olson indicates the May Creek project will not likely create a measurable increase in bank erosion (IEltlhobut 24G}. 0 June 14, 2012: Ecology letter confirms that King County has addressed concerns about the project (IEltlhobit 241Hl}. 0 August 1, 2012: Analysis by King County staff (Turney and Bethel} verifies default values in model used by Olson were reasonable in this case ( IEltlh o bot 24~}. 0 September 26, 2012: Joint Ecology/Corps Public Notice Reposted 0 November 14, 2012: King County DPER Issues Clearing and Grading Permit (IEltlholblot 26}. 0 January 8, 2013: Ecology Issues 401 Water Quality Certification Approval (IEltlholblot 2s}. 0 No design changes resulted from the additional analysis conducted. . i--- 1 l_ Changes ( cont.) 0 Permits obtained to date: 401 WQ Certification, CZM Consistency Determination, Construction Stormwater General Permit (NPDES) Hydraulic Project Approval, King County Clearing and Grading Permit, King County Flood Hazard Certification 0 Still working with the US Army Corps of Engineers to obtain a Section 404 Permit. ~ Currently the Corps and the Muckleshoot Indian Tribe have concerns about the adequacy of mitigation for in-stream habitat impacts in the valley, within King County. ~ King County is proposing additional mitigation for in-stream habitat impacts in the valley, in the form of payment to the In- Lieu-Fee Program. 0 This approach has been preliminarily determined to be acceptable by the Corps (Meeting April 10, 2013) and King County is currently working on the documentation to formalize the proposal. r I ' I I I _ .. 3-0C:015 , C ify oi !Re Dil fto Oil City Of Rent J Planning Divisio, , lffe\~[Q') (UJ~lE frE~~~r. ~ffe\~l[E~ ffe\f fl~(Cffe\ 1~(0)~ FEB I 2 2013 PROPERTY OWNER{S) I I PROJECT INfORi\llATION PROJECT OR DEVELOPMENT NAME: NAME: Stonegate Homeowners Association Happy Longfellow, President May Creek Drainage Improvement Project (9A1205) ADDRESS: 5405 NE 24'" Ct PROJECT/ADDRESS(S)/LOCATION AND ZIP CODE: Open space on the west side of 148th Avenue SE Just CITY: Renton ZIP: 98059 south of Its Intersection with SE May Valley Road In Renton, WA 96059. KING COUNTY ASSESSOR'S ACCOUNT NUMBER(S): TELEPHONE NUMBER: (425) 204-1119 APPLICANT (if other than owner) I 803540TR-A NAME: Doug Chin on behalf of King County Water and Land Resources Division EXISTING LAND USE(S): Open Space Tract PROPOSED LAND USE(S): COMPANY (if applicable): King County Water and Land Resources Division Open Space Tract EXISTING COMPREHENSIVE PLAN MAP DESIGNATION: ADDRESS: 201 South Jackson Street, Suite 600 Residential -1 PROPOSED COMPREHENSIVE PLAN MAP DESIGNATION CITY: Seattle ZIP: 98104 (If applicable) Resldentlal • 1 EXISTING ZONING: TELEPHONE NUMBER: (206) 296-8315 R-1 CONTACT PERSON I PROPOSED ZONING (n applicable): R-1 SITE AREA (In square feet): NAME: Doug Chin, Project Manager Approximately 33,600 square feet SQUARE FOOTAGE OF PUBLIC ROADWAYS TO BE COMPANY (ii applicable): King County Water and Lsnd Resources Division DEDICATED: Not annllcable. SQUARE FOOTAGE OF PRIVATE ACCESS EASEMENTS: ADDRESS: 201 South Jackson Street, Suite 600 N/A PROPOSED RESIDENTIAL DENSITY IN UNITS PER NET CITY: Seattle ZIP: 98104 ACRE (If applicable) Not annllcable. TELEPHONE NUMBER AND EMAIL ADDRESS: NUMBER OF PROPOSED LOTS (if applicable) Not applicable. (206) 296-8315 doug.chln@klngcounty.gov NUMBER OF NEW DWELLING UNITS (If applicable): Not applicable. ' F:\DOUGC\DOUGCHIN\May Creek 2010\Renton Permits\l..and Use Permit Master Application\Stonegate Renton Master App Porm.docx • I • I I I PR&cr INFORMATION (coniin.d) ,......;'---'-'-----'--'-------------, NUMBER OF EXISTING DWELLING UNITS {If applicable): PROJECT VALUE: Not applicable. $350,000 {Includes project area outside City limits) SQUARE FOOTAGE OF PROPOSED RESIDENTIAL BUILDINGS {If applicable): Not applicable. IS THE SITE LOCATED IN ANY TYPE OF ENVIRONMENTALLY CRITICAL AREA, PLEASE INCLUDE SQUARE FOOTAGE {if applicable): SQUARE FOOTAGE OF EXISTING RESIDENTIAL . BUILDINGS TO REMAIN {if applicable): Not applicable. Cl AQUIFIER PROTECTION AREA ONE SQUARE FOOTAGE OF PROPOSED NON-RESIDENTIAL a AQUIFIER PROTECTION AREA TWO BUILDINGS {If applicable): Not applicable. a FLOOD HAZARD·AREA sq. ft. SQUARE FOOTAGE OF EXISTING NON-RESIDENTIAL BUILDINGS TO REMAIN {If applicable): Not applicable. a GEOLOGIC HAZARD sq. ft. NET FLOOR AREA ON NON-RESIDENTIAL BUILDINGS {if a HABITAT CONSERVATION sq. ft. applicable): Not applicable .. ~ SHORELINE STREAMS & LAKES 5,300 sq. ft. NUMBER OF EMPLOYEES TO BE EMPLOYED BY THE NEW PROJECT {If applicable): Not applicable. ~ WETLANDS 28,300 sq. ft. llEGAL IOIESCRll?llON OF PROPIEIRTY (Attach leaal descrlation on seaarate sheet with the followina Information Included! SITUATE IN THE SECTIONS 2 & 3, TOWNSHIP 23N, RANGE 5E, IN THE CITY OF RENTON, KING COUNTY, WASHINGTON TYl?IE OF APl?!...ICATION & FEES List all land use applications being applied for: 1. Grade & Fill Permit 3. 2. Variance 4. Staff will calculate applicable fees and postage: $ AFfllOAVIT Of OWNIERSHIP l, (Print Name/s) Sge attached oaBement , declare under penalty of perjurlunder the laws of the State of Washington that I am (please check one)_ the current owner of the property Involved In this sppllcatlon or_;;/_ the authorized representative to act for a corporation {please attach proof of authorization) and that the foregoing statements and answers herein contained and the Information herewith are In all respects true and correct to U,e best of my knowledge and belief. 1 certify that I know or have satisfactory evidence that Httell'i Liw.,Jl.., 1 IQuJ signed this Instrument and acknowledge it to be his/her/thefrifue~tary act for the uses end purposes mentioned In the Instrument. ;""~''JQ 11111•11 v)ft,L '--('\ I "111~ ,?.""' • '"'""'"'J./lft.~11~ NotmyPubl)clna-..hoJhe State of Washington I I -\\$ION 111 •11,)"b\ --=---:---=----=---.-.,-~~ ¥..J'&. ~ , L · , I h (SlgnatureofOwner/Representallve) f& ~-• _J.1~~ tary(Print>':!efUi) I\\. \..JQ ll\20i\ ;,\,9 :.~~~~~J~ appantmentexplres; ff //q(t+ 'It,~ O~"'"""" \~"if_ F:IDOUGC\DOUOCHIN\May Creek 2010\Renton !t..VJ"li,~~Li, Master Application\Stonegate Renton Master App Fonn.docx • 2 -, ruriw.,.,~~1111 MAY CREEK DRAINAGE IMPROVEMENT PROJECT (KING CO) · MAY CREEK FROM APPROX SE 152ND ST TO BEY c:inrv OIF IRIEN1J"ON IDepairtmenrll: olf Comm11.n01Joty aJD1ldl IEcoB11omuc 1DevelopmeB11t C11.nrreB11t 1Plai01JB11001J91 IDovosoollil Contact Information: PRE10-044 October 28, 2010 Planner: Gerald Wasser Phone: 425-430-7382 Public Works Reviewer: Jan Illian Phone: 425.430.7216 Fire Prevention Reviewer: Dave Pargas Phone: 425.430. 7023 Building Department Reviewer: Craig Burnell Phone: 425.430.7290 City of Renton P\ann\ng Oiv1s1on . Please retain this packet throughout the course of your project as a reference. Consider giving copies of it to any engineers, architects, and contractors who work on the project. You will need to submit a copy of this packet when you apply for land use and/or environmental permits. · Pre-screening: When you have the project application ready for submittal, call and schedule an appointment with the project manager to have it pre-screened before making all of the required copies. · The pre-application meeting is informal and non-binding. The comments provided on the proposal are based on the codes and policies in effect at the time of review. The applicant is cautioned that the development regulations are regularly amended and the proposal will be formally reviewed under the regulations in effect at the time of project submittal. The information contained in this summary is subject to modification and/or concurrence by official decision-makers (e.g., Hearing Examiner, Planning Director, Development Services Director, Department of Community and Economic Development Administrator, Public Works Administrator and City Council). C DEPARTMENT OF COMMUNITY AND ECONOMIC DEVELOPMENT DATE: TO: FROM:. SUBJECT: MEMORANDUM October 22, 2010 Jerry Wasser, Planner Jan Illian, Plan Review t May Creek Drainage Improvements SE 152"' Street and 148 Ave SE PRE 10-044 NOTE: The applicant is cautioned that information contained in this summary is preliminary and non- binding and may be subject to modification and/or concurrence by official city decision-makers. Review comments may also need to be revised based on site planning and other design changes required by City staff or made by the applicant. I have completed a preliminary review for the above-referenced proposal. The following comments are based on the pre-application submittal made to the City of Renton by the applicant. Storm Drainage The following are comments regarding the proposed King County May Creek Drainage Improvement Project for use in the pre-application meeting and incorporating into the City's comment letter on the JARPA public notice. 1. A hydrologic and hydraulic report is needed for the project that evaluates the pre-project and post- project condition, to evaluate and determine if the project will cause any impacts within the project limits and downstream of the project. The report will need to look at the change· in flow depth, velocity·· of flow at the 148'" Ave SE road crossing, the downstream limit of the project, and a minimum of 1'-mile downstream of the project. The report will need to include channel cross-sections that show the pre- project and post-project water surface elevations and channel profiles. The hydrology may be based upon the May Creek Basin Plan or updated hydrology, if this has been done by the County. The hydrologic and hydraulic analysis will need to look at a range of flows between the 2-year flood .frequency and the 100-year flood frequency, ideally the 2, 10, 25, 50, and 100-year storm events. Any change to the 100-yr floodplain elevation will need to be determined and shown in the·study. 2. A fluvial geomorphologic analysis of the project, utilizing the information from the hydrologic/hydraulic report to evaluate and determine if the project will affect stream bank erosion, channel incision, or other changes that could occur in the project area or impact downstream properties. • May Creek Drainage-PRE 10-035 Page 2 of 2 October 22, 2010 3. The project will need an Erosion and Sediment Control (ESC) Plan and Storm Water Pollution Prevention Plan for the project that complies with the 2009 King County Surface Water Design Manual standards. The ESC Plan will need to include measures to control dust and tracking of sediment on to streets during construction. 4. The City's Critical Area Ordinance requirements related to flood hazards will need to be addressed for work in the FEMA 100-year floodplain to meet requirements regarding compensatory storage for any filling in the floodplain. The 100-year floodplain boundary will need to be shown on the project construction plans. 5. A traffic control plan will need to be submitted and approved prior to the start of construction for the construction entrances on 1481h Ave SE. Construction hours will be in accordance with City standards (7:00 AM -8:00 PM), or as established in the approved traffic control plan. 6. Information about ownership, maint~nance, and operation responsibilities for the improvements within the portion of the project in Renton is needed. ,What are the monitoring and maintenance requirements for the project? Will King County be responsible for meeting these requirements? (" DEPARTMl=I\IT nc rn••• •. ••··-· _ ' -· PLANNING DIVISION WAIVER.OF SUBMITTAL REQUIREMENTS FOR LAND USE APPLICATIONS Grading Plan, Conceptual 2 Grad1ng,-pianp,ttlelalled:;/;,;,,,,,,,.;;"";,,., Habitat Data Report 4 Landscape Plan, Conceptual, t.anoscape pia,.;; De!a1111cii· : : : : · · · Legal Description 4 Master Application Form 4 Morwnii#mf¢.ita~,('9c@P-~cmtin>!rn~h\}+'''''''''''''''''''''''''' Neighborhood Detail Map 4 •Pa/klofi;•tot covsra\i~H&'tano~caiiiinti•Ana1Ysis ,••• Plan Reductions (PMTs) 4 This requirement may be waived by: \<C.. M,b...V C eEFk pt:~ .. b .. O .. .J.AGJ"2 t/1-il..P~~-r 1. Property Services PROJECT NAME: P?€: IP -o :t<-t: 2. Public Works Plan Review 3. Building 4. Planning DATE: [P /5J...?, b=10 r1 f·-Mr.Fmn::it;1\Forms.Temolates\Self·Help Handouts\Planning\waiverofsubmittalreqs.xls 06/09 " ,,_ ™·· 111tfirW11 KC May Creek Drainage Ir 1ement, PRl:10-044 Page 2 of 3 October 28, 201 O enhancements to wetland fish habitat include the placement of large woody debris and stream bed gravel alcoves. Current Use: The parcel which the applicant has identified as being directly affected by the proposed project is a vacant open space tract owned by the Stonegate Homeowners Association. This parcel would remain vacant upon project completion. Critical Areas: The project area within the City of Renton includes May Creek, a Class 2 Stream, a wetland on the north side of May Creek, and it is within a flood hazard area. Note: The Wetland Delineation Report submitted with the pre-application materials identifies the onsite wetland as a King County Category II riverine wetland. The applicant must provide the City of Renton wetland classification in order for staff to accurately evaluate compliance with the wetland provisions of the Code (RMC 4-3- 0SOM). At the time of formal submittal for projects involving work in wetlands the applicant is required to provide an evaluation of alternative methods of development (RMC 4-3- 0SOM.8), a plan for compensating for wetland impacts (RMC 4-3-0SOM.9), a proposal for a mitigation approach that includes wetland restoration, creation, and enhancement (RMC 4-3-0SOM.10). Ratios for wetland creation or restoration are addressed in RMC 4- 3-0SOM.ll and ratios for wetland restoration or creation plus enhancement are addressed in RMC 4-3-0SOM.12. Additionally, the applicant must provide a mitigation monitoring plan for streams and wetlands in compliance with RMC 4-3-0SOF.8 and 4-3- 0SOM.16. Mitigation monitoring is required for a 5-year period with reporting done quarterly for the first year and annually thereafter. The monitoring reports should indicate the number of floodplain acres filled and restored. A surety device would also be required as a condition of approval of any mitigation plan. Environmental Review: King County has issued a threshold Mitigated Determination of Non-Significance for the proposed project. Permit Requirements: A Critical Areas Exemption for Flood Hazard Reduction in Streams and Lakes would be required (RMC 4-3-0SOC.5.d.iii). There is no fee for critical areas exemptions. Administrative Approval for Alterations of Streams and Lakes or Associated Buffers-:- Dredging would also be required (RMC 4-3-0SOL.8.d.ii). The applicant will be required to provide an evaluation of the criteria necessary for administrative approval alterations of streams and Jakes or associated buffers for dredging. A Special Fill and Grade Permit would be required (RMC 4-9-080F.2). Because the proposed project would involve the excavation of 1,550 cubic yards of material, it is considered a Major Activity (RMC 4-9-080F.l.a) and requires Hearing Examiner review. The foe for a Special Fill and Grade Permit is $2,000.00. In addition, to an approved Special Fill and Grade Permit, an Annual Grading License is necessary. Such grading license would be issued by the Development Services Division for not more than one KC May Creek Drainage lmpro"· -.ent, PREl0-044 Page 3 of 3 October 28, 2010 • year and may be renewed if the operation is progressing according to the approved plans. If the applicant cannot comply with the wetland provisions of the Code (see note in Critical Areas section, above), a Critical Areas Variance would be required (RMC 4-9- 250). The fee for a variance is $1,200.00. Note: The protection of properties not directly affected by this drainage improvement project must be addressed in the formal submittal. The potential affects on surrounding and downstream properties should be addressed. The above approvals would be processed concurrently within approximately 6 to 8 weeks. The Critical Areas Exemption and the Administrative Approval for stream alterations regarding dredging would be processed administratively prior to any public hearing. Subsequently, the Special Fill and Grade Permit and any Critical Area Variance would be considered by the Hearing Examiner at a public hearing . . - I ·-----_J 1---·· W-i=' g.1_'. ~r- !:: 11:.; I ! R-8 I i ,.111,st-·-··-• ' ) l C ···--·-·· I 1-i-- i-- ' ---1--·· si:11:m.a.·-- RM-F I I r ---------·---- ZONING MAP BOOK PW TECHNICAL SERVICES PRINTED ON 11/13/09 ,,..-.,.n,a•r-,.~-''°"'"" -·---·--... ---·°'""----~-d ... CJtr ........... _ .... ' ' I R-1 · ,··---, ,----- __ i : ) , I E6 -10 T23N RSE E 1/2 200 400 I I,,., 1:4,800 1 _ ·-----· ..J 03 T23N RSE E 1/2 5303 • PLANNING DIVISION ~ WAIVER"OF SUBMITTAL REQUIREWIENTS FOR LAND USE APPLICATIONS .. : . • :· LANO use PERMIT suaM'rirnAL • . . . .. . • •. ·' ::.:. iteauiRtMENfst. ·_.·... . . Calculations 1 Habitat Data Report 4 ,l@m;ivEimellt D¢f¢rrsll!zf f!:!U•,H!f!U!Hf:•':f't i!f i:/UU!i! iii:!. !i•i!! Irrigation Plan 4 K1n~•couney.•A$sesscir'$•M1;1p,tn~1ciiitmg:Si!ef••·•••·•··•·•· Landscape Plan, Conceptual, ilfilidscaiiei"F•1an; oe1a\iec1/''''i' • · ·:·· · Legal Description 4 -Mapjof:)Exlshng·;s,1e:Coodit1Ms•,!!(--;i!,UH:i!}··,::::•·:,·•:: Master Application Form 4 ·Neighborhood Detail Map 4 'Piirkliig)•UiWC.6yi!i~a9~aa<:t./ii'idsC?Pii'ig•A~aW$is''i••••: Plan Reductions (PMTs) 4 This requirement may be waived by: 1. Property Services 2. Public Works Plan Review 3. Building 4. Planning 1-Hf"::Fn\nl'ltA\Fanns-Temolates\Self-Help Handouts\Planning\waiverofsubmittalreqs.xls 06/09 a.. PLANNING DIVISION .::. WAIVL_~ OF SUBMITTAL.REQUl1-.~MENTS FOR LAND USE APPLICATIONS Wetlands Mitigation Plan, Final 4 )N:eti~nos/vhtigi;iti6H Plah,):P/el1rnmaty 4::::: )':):'::):):): ·,;: Wetlands Report/Delineation 4 w1re1as$.••-••••:::.••••-•-•••-•'-•:::••••'•'•.u::::••••••.uu:::::_nu,:::n•• rn:::y:,::::::rn::•• Applicant Agreement Statement 2 AND 3 Inventory of Existing Sites 2 AND 3 Lease _Agreement, Draft 2AND 3 Map of Existing Site Conditions 2 AND 3 Map of View Area 2 AND , PhDtosimulations 2 AND 3 This requirement may be waived by: 1 . Property Services KC.. MAC;,J C...\?¥-E t::..-D~I ,-J~ I Mf?T20Jt;;. i,\AE;f.-i-(' PROJECT NAME: f?£;E /0 -D lfL.1-. 2. Public Works Plan Review 3. Building 4. Planning H;\CEO\Dala\Forms-Templates\Self-Help Handouts\Planning\waiverofsubmittalreqs.xls -- DATE: fo/:z,.g/&,o\Q r l I I 06/09 Project Name Project# DOT Oracle# AWARD .AR CUST# Last inspection Date 2012:13 charges Last Bill CINDY -Comments UNPAID Ray Comment 160th Interchange Plaza B02C0216 1027198 113779 233319 s -s 247.25 c/o Collections Goat Hill ROW L08RW024 1027406 114028 231999 s -s 339.70 c/o Collections Vashon Wastewater Treatment Plant B03C0126 1026842 --DO NOT USE 1026842; YOU CAN CHARGE DIRECTLY TO wro PROJ 1038099 05/29/2012 Boulevard Park Grading Permit L99G0051 1027265 114013 233104 s s 470.37 c/o Collections Maxwell SP L0550061 1027567 114087 233692 s 198.34 . holding for WLRD s 1.60 . Pine Classics Subdivision L98P0012 1027566 114086 233692 s 148.76 holding for WLRD s 1.60 Woodbrook4 I What's the project#? -Ray l release letter to WLRD 1/29/13 Cedarwood Div 6 LOOP0014 1027053 113981 232747 s -$ 1,008.39 c/o Collections Chuong SP (DOT only) L04S0005 1027350 114024 233320 07/16/2012 $ 333.19 s 333.19 Gough SP (FKA Pitzer SP) L05S0057 1027563 114083 233601 s -$ 2,631.10 c/o Collections Kelly's Latte Stand B06C0180 1026716 102517 383 07/16/2012 $ 283.58 s -PAID Livingston ROW L06RW010 1027352 114025 233489 s -s 240.70 c/o Collecti,... .... c;. _ Tahoma HS PH 1 B98C0134 1026786 102439 294 11/15/2012 $ 353.18 s 353.18 - May Valley Service Center B01C0035 1027492 114072 233798 10/12/2012 $ 488.32 10/31/2012 s PAID Stoneridge ROW L04RW029 1027268 114007 231989 08/29/2012 $ 733.33 s -PAID Khosa SP L05S0062 1026852 114044 295 11/29/2012 $ 349.40 12/31/2012 s 250.22 For Dec inv Shamrock Grading L05CG150 1027045 113976 247012 11/15/2012 $ 980.23 s PAID Scoccolo ROW L07RW008 1026840 114125 232136 11/15/2012 $ 446.96 12/31/2012 s 250.22 For Dec inv City of Rentorn lAND !LJJSE !PERMIT AIPIPl!CAl!ON May Creek Drainage Improvement Project Project Narrative 2-12-2013 City of Renton Planning Division FEB 1 2 ZU1J Location [FR~«;!E~W!E[Q) King County's Water and Land Resources Division (WLRD) proposes to improve in- stream flow conditions along the reach of May Creek between approximately River Mile 4.3 and 4.9 near the cities of Newcastle and Renton. The project is located in the May Valley on the south side of SE May Valley Road (Sections 2 and 3, Township 23N, Range SE). The portion of the project in the City of Renton is located in the open space tract (Parcel 803540TR-A) on the west side of 148th Avenue SE and covers approximately 3.75 acres. The proposed project requires a City of Renton Grade & Fill Permit and a Critical Areas Variance. Existing Land Use The current use of the site is a designated open space tract, zoned R-1, containing critical areas and is owned by the Stonegate Homeowners Association. Land use adjacent to the site is a combination of rural residential with small farms and undeveloped open space. The current zoning classification adjacent to the site is primarily RA-5 and RA-I 0, rural residential with future development limited to rural uses with maximum densities of one house per five acres and ten acres, respectively. Streams. Wetland. Soils The project site contains a Category 3 wetland with a 25-foot buffer, and a Class 2 stream (containing salmon ids) with a I 00 buffer. Due to prolonged inundation at the project site, soils are hydric. The soils are slow draining with high clay content. The proposed project will occur within the delineated wetland boundary and the ordinary high water mark of May Creek. Proposed Use Within the City of Renton, the project proposes to remove accumulated sediment (approximately 392 cubic yards) from approximately 160 linear feet of the May Creek channel, and remove flow obstructing vegetation (e.g., reed canarygrass and willow branches) from approximately 540 linear feet of channel. Additional sediment and vegetation removal will happen in May Creek outside the city limits. As mitigation for removing the sediment and vegetation, 15 feet of riparian/wetland vegetation will be planted on both side of May Creek both within the City of Renton, and also outside the city limits. In addition, approximately 3 acres of riverine wetland will be enhanced. Enhancements will include approximately 0.24 acres of off-channel alcoves, reed canary grass suppression, planting with native vegetation, and large woody debris placement. Split-rail fencing and sensitive area signage will be installed around the mitigation site. King County is the process of coordinating with the property owner to determine whether the fencing will be installed to follow the boundary of the parcel or boundary of the mitigation area. The boundary of the parcel would be the larger of the two areas. Page 1 of 2 Site Access • • Ciity off Reo,~on .· 1!..ANID !UJSIE IPIERM!ll" AIPIPl!CAll"!ON May Creek Drainage Improvement Project Project Narrative 2-12-2013 Site access will be provided by a temporary construction road off 148th Avenue NE. Additional access within the wetland and floodplain will be provided by using rubber tired or tracked equipment. This equipment can move over the landscape with minimal ground disturbance. The estimate fair market value of the entire project (including areas in and outside the city limits) is $350,000. Tree Removal Flow obstructing vegetation will be removed from the channel as described above; however, no trees greater than 6-inch diameter breast height, will be removed. Page 2 of 2 City of 1Re01to01 City oft-. ------------------------~-=.,. '"'fn1to anr11ng D· . n I Vision lANID USIE PEIRMll APPllCAllON May Creek Drainage Improvement Project Justification for Variance Request 2-12-2013 FEB 1 2 ZOIJ IR?~ . King County Water and Land Resources Division (WLRD) is requesting a Critiaf/~/!i/JW'/fI:rR-. Variance from the City of Renton to improve flow conditions in May Creek. Work within If).; the city limits is proposed in May Creek and the adjacent wetland immediately west of 148'h Avenue SE on Parcel 803540TR-A. The following proposed activities in the stream and wetland require a variance: , Dredging: Removal of accumulated sediment (approximately 392 cubic yards) from approximately 160 linear feet of the May Creek channel. , Vegetation Removal: Removal of flow obstructing vegetation (e.g., reed canarygrass and willow branches) from approximately 540 linear feet of the May Creek channel. , Wetland/Stream Enhancement: Riparian habitat will be enhanced by planting 15 feet of native riparian/wetland vegetation on both sides of May Creek. In addition, approximately 3 acres of existing riverine wetland will be enhanced. Enhancements will include approximately 0.24 acres of off-channel alcoves, reed canary grass suppression, planting with native vegetation, and large woody debris placement. This variance request is necessary because sediment accumulation and in-stream vegetation (e.g., reed canarygrass and willows) throughout the valley reach of May Creek have been gradually decreasing channel flow capacity, causing a backwater effect. This is increasing the duration of flooding in actively used pastures on adjacent rural residential properties with flood conditions now persisting well into the summer months. The goal of this project is to reduce the duration of flooding on these properties at both sides of the rainy season by removing in-stream channel obstructions. This effort should help alleviate the duration of localized flooding on adjacent properties during low to moderate storm events and should allow the pastures to drain more effectively when flooding does occur. King County WLRD is providing the following justification for this variance request per Section 4-9-2508 #IO in the Renton Municipal Code. Renton Municipal Code Section 4-9-2508 10. Special Review Criteria -Public/Quasi-Public Utility or Agency Altering Aquifer Protection, Geologic Hazard, Habitat, Stream/Lake or Wetland Regulations: In lieu of the variance criteria of subsection B5 of this Section, applications by publidquasi-public utilities or Page 1 of 6 Ma#..eek Drainage Improvement Pro1lt Justification for Variance Request agencies proposing to alter aquifer protection, geologic hazard, habitat, stream and lake or wetland regulations shall be reviewed for compliance with all of the following criteria: a. Public policies have bee/I evaluated and it has been determined by the Department Admi1tistrator that the public's health, safety, al!d welfare is best served; King County has designed this proposal to protect public health and safety. Sediment accumulation and in-stream vegetation throughout the valley reach of May Creek as been increasing the duration of flooding in actively used pastures on adjacent rural residential properties. The goal of this project is to reduce the duration of flooding on these properties by removing in-stream channel obstructions, restoring a buffer of native riparian vegetation (approximately 15 feet wide on each side of the stream) along May Creek, and enhancing the existing riverine wetland. To protect public health and safety during construction, public access will be limited during construction. King County will coordinate with the property owners to ensure that they know when access will be limited to their property so they can plan ahead. Construction crews will allow access to these areas only when public health and safety can be maintained. To ensure that public health and safety is protected post-construction, King County completed numerous studies and is performing ongoing monitoring to analyze the potential effects on adjacent properties, specifically properties downstream of the project area. These studies include: I. Hydraulic and Hydrologic Analyses, December 17, 20 I 0 2. Sediment Assessment Memo, February 9, 2011 3. May Creek Phase 4 Monitoring Report (DRAFT), last updated 5-2-2011 4. Post-Construction Erosion Monitoring Plan, August, 4, 2011 5. Analysis of the Backwater Effect caused by the McFarland (i.e, Gambini) footbridge, December 14, 2011 6. Comparison of Post-Project Changes in Flow Durations and Frequencies for Various Storm Events, January 11, 2012 The studies show that these activities will not further contribute to ongoing erosion on properties downstream in May Canyon. In summary, this is because this project addresses flow conditions that occur during low to moderate storm events (less than the one year flow event), while the erosion in the canyon is triggered by large storm events. The project will not change the stream flow during large storm events, and therefore will not change erosion patterns downstream. King County has been collecting baseline monitoring data downstream and attempted to continue baseline monitoring into 2012 but at the end of 201 l requests to key property owners, including Rollins/Duffus, for access to continue collection of monitoring data were not approved. Also, although Rollins/Duffus had agreed to Page 2 of 6 IVI~, Creek Drainage Improvement P,. ,ect Justification for Variance Request do monitoring themselves and send in data, nothing has yet been reported to King County. King County can only conclude that there has not been any additional erosion, otherwise property owners would have informed us of any problems. Assuming that property access is provided, King County is committed to monitoring conditions downstream for a period of 5 years after the project is completed as described in the Post-Construction Erosion Monitoring Plan (August 2011 ). If the data collected from the monitoring during this time clearly shows that an erosion problem resulted from the project and does impact individual properties, then King County is committed to responding to the property owner and the City of Renton to provide technical assistance and.determine responsibilities of King County to perform any remediation. b. Each facility must conform to the Comprehensive Land Use Plan and with any adopted public program, and policies; This project will not change existing land use. c. Each facility must serve established, identified public need,; This project is proposed to serve the public by protecting existing agricultural uses in the May Valley. d. No practical alternative exists to meet the needs; Other alternatives examined that would potentially reduce flooding in May Valley and provide property owners with more usable pastureland included: I. Restore a May Creek channel corridor that corresponds to the King County regulatory buffer of 330 feet ( 165 feet on either side of the stream). This alternative would involve purchasing land, but would not require the demolition or relocation of any home or structures. It would require that property owners relinquish existing pasture land in the buffer in exchange for pastureland either offsite, or in the form of constructed farm pads onsite within the 100-year floodplain (see alternative #4). This alternative was not feasible due to the large amount of private property that King County would need to buy. Funding is not available for property purchases of this magnitude, and even if funding were available, the property owners are not necessarily interested in relocating their existing land uses to another location. 2. Construct flood control berms along May Creek. This alternative would require placing fill in the 100-year floodplain and associated wetland, and would further disconnect May Creek from its floodplain. This alternative would have more adverse impact on critical areas than the chosen alternative. Page 3 of 6 MaJlleek Drainage Improvement Pro.fa Justification for Variance Request 3. Construct upland stonnwater controls for upland sources of sediment, including the addition of retention and detention facilities. This alternative would not meet the project goal to reduce the duration of flooding for low to moderate storm events. Upland stormwater controls would mitigate flows that are half of the two year event and greater. Controlling flows greater than half the two year event would not stop fines from flowing through the drainage system. This project targets flows well below half of the two year event. Therefore, upland detention is not a feasible option to reduce flood durations during small storm events. 4. Implementation of farm management plans and construction of farm pads. While this alternative would eliminate the need for dredging and would maintain May Creek's existing connection to the l 00-year floodplain, it would require the placement of fill in the l 00-year floodplain (for construction of farm pads) and would potentially result in a loss of wetland area. As a result, this alternative would likely have more long-term adverse impact on critical areas than the chosen alternative. The proposed project, which includes removing channel obstructions while also providing compensatory stream and wetland mitigation, was the alternative with the least adverse impact on critical areas that was within the available King County budget. e. The proposed action takes affirmative and appropriate measures to minimize and cmnpensdte for unavoidable impacts; The project has been designed to avoid and minimize adverse impacts on critical areas to the maximum extent possible without compromising the project goals. The following avoidance and minimization methods have been incorporated to protect critical areas: 1. Construction equipment will use existing farm access roads, whenever possible to cross the wetland, floodplain, and stream. 2. When wetland access is needed outside of existing farm roads, only rubber tired and tracked construction equipment will be allowed. This type of equipment can move over the landscape with mfoimal ground disturbance. 3. Temporary erosion and sediment control best management practices, such as silt fences or coir logs, would be used to prevent sediment-laden storm water runoff from entering the stream or wetland. As needed, additional best management practices may include collecting sediment- laden stormwater before it enters the stream or wetland and discharging the stormwater into a vegetated upland location instead. Please refer to the Page 4 of 6 l\i,_, Creek Drainage Improvement F-. -Ject Justification for Variance Request project's Construction Water Quality Protection and Monitoring plan for a detailed description of the proposed best management practices. 4. Any wetland areas that are temporarily disturbed during construction will be restored with native wetland vegetation after construction is complete. 5. To minimize the amount of temporary ground disturbance in the wetland, reed canarygrass will be removed from the planting areas using a weed barrier fabric instead of excavation. Native vegetation will be planted through the fabric. 6. All in-water work will be conducted during the summer low flow construction work window that is designated to protect aquatic species. 7. During the sediment removal, the stream will be temporarily diverted around the work area as part of the temporary erosion and sediment control plan. This diversion may involve using one or more gas-powered pumps to remove water from the channel just upstream of the work area. The water would then be discharged downstream of the work area. 8. In-stream vegetation removal will be completed by hand, when possible, to minimize turbidity in the stream and to avoid removing more vegetation than is necessary to restore flow conditions. When machine removal is required, the. stream will be temporarily diverted around the work area as part of the temporary erosion and sediment control plan. 9. Hand removal of in-stream willow removal will be limited to the minimum amount required to restore flow conditions. Branches that are crossing the stream and obstructing flow will be removed by pruning the branches back to the trunk. Willows that are providing canopy cover for the stream without obstructing flow will not be removed, and similarly, the willow roots that are providing bank stability will not be removed. 10. May Creek will be protected during construction of the off-channel alcoves west of 148th Avenue SE by either leaving an earth plug between the existing stream channel and the excavation area for the alcove, or by bypassing the stream around the work.area. If an earth plug is used, prior to removing the plug and connecting the alcove to the existing channel, a turbidity curtain will be installed to protect the stream during the connection. The construction method to be used (i.e., earth plug or stream bypass)will be determined in the field based on which method will best protect water quality given the site conditions. f The proposed activity results in no net loss of regulated wetland or stream/lake area, value, or function in the drainage basin where the wetland. stream or lake is located; Page 5 of 6 Ma/lteek Drainage Improvement Pro. Justification for Variance Request The activity will not result in a loss of regulated wetland area or function. The sediment and vegetation removal will impact existing in-stream fish habitat. Compensatory mitigation is proposed to offset these impacts. Please refer to the Stream and Wetland Impact Analysis and Mitigation Plan (Revised September 2011) for a complete description of the impacts and mitigation. g. The proposed activities will not jeopardize the continued existence qf endangered, threatened or sensitive species as listed by the Federal government or the State; The activity has been evaluated under Section 7 of the Endangered Species Act. The evaluation determined that the project may affect but is not likely to adversely affect Chinook salmon and steelhead trout. The project will have no effect on bull trout. No other sensitive species are located in the project area. h. That the proposed activities will not cause significant degradation of groundwater or surface water quality; Best Management Practices will be used during construction to protect groundwater and surface water quality as described in Section 5.1 of the Stream and Wetland Impact Analysis and Mitigation Plan. Construction and post- construction monitoring of surface water and groundwater will be conducted as described in Section 6.2 of the plan. In addition, this project has obtained an Individual 401 Water Quality Certification from the Washington State Department of Ecology (Ecology) and will follow all permit conditions set forth by Ecology for the protection of groundwater and surface water. i. The approval a,· determined by the Reviewing Official is a minimum variance that will accomplish the desired purpose; and (Ord. 5519, 12-14-2009) The project has been designed to avoid and minimize adverse impacts on critical areas to the maximum extent possible without compromising the project goals and is therefore requesting the minimum variance possible. Please refer to item e for the list of avoidance and minimization measures. j. The proposed variance is based on consideration of the best available science as described in WAC 365-195-905; or where there is an absence of valid scientific information, the steps in RMC 4-9-250F are followed. (Ord. 4835, 3-27-2000; Amd. Ord. 4851, 8-7-2000). Please refer to the attached document index for a list of studies using best available science that informed the design of this project. Page 6 of 6 ·. May Creek Drainage Improvement Project Document Index for City of Renton Permit Submittal *Items submitted with the 2011 application are shown in italics Historical Documentation on the May Creek Basin I. May Creek Basin Plan, April 2001 2. May Creek Drainage and Restoration Plan (GeoEngineers), December 19, 2008 3. May Creek Sediment Transport Study (Anchor QEA), June 2009 4. May Creek Erosion Stabilization Draft Report (Anchor QEA), January 20 I 0 Project Specific Erosion and Hydraulic Analysis/Monitoring 5. Hydraulic and Hydrologic Analyses, December 17, 2010 6. Sediment Assessment Memo, February 9, 2011 7. May Creek Phase 4 Monitoring Report (DRAFT) last updated 5-2-2011 8. Post-Construction Erosion Monitoring Plan, August, 4, 20 l l 9. Documentation Exchanged between Ecology and King County a. Patricia Olson Memo, August 2011 b. Ecology Comment Letter September I, 2011 c. King County Response Letter September 16, 2011 d. King County Response Letter 2-9-2012 with enclosures i. Analysis of the Backwater Effect caused by the McFarland (i.e, Gambini) footbridge, December 14, 2011 ii. Comparison of Post-Project Changes in Flow Durations and Frequencies for Various Storm Events, January 11, 2012 111. See Item #7 (May Creek Phase 4 Monitoring Report) e. Memo from Patricia Olson dated 5-22-2012 f. Letter from Erik Stockdale (Ecology) dated 6-14-2012 g. Bank Stability and Toe Erosion Model memo dated 8-1-2012 Project Critical Areas and Wildlife JO. Wetland Report, March JO, 2010 11. Report of May Creek Monitoring Well Installation, October 12, 2010 12. City of Renton Wetland Rating Addendum, November 17, 2010 /3. Baseline Stream Conditions Report, December 2, 2010 14. Biological Evaluation for Chinook Salmon and Steelhead Trout, February 2011 15. No Effect Determination Letter for bull trout, February 2011 Project Design and Construction 16. May Creek Alternatives Analysis (prepared for Corps), 4-25-2011 17. Stream and Wetland Impact Analysis and Mitigation Report, 9-7-2011 18. Long Marsh Creek Basis of Design Report, 9-16-2011 19. Construction Water Quality Protection and Monitoring Plan, 9-7-2011 Pagel of2 • • Project Permits and Approvals 20. SEPA MDNS and Environmental Checklist, issued 9-8-2010 21. NPDES Construction Stormwater General Permit, issued 5-26-2011 22. Hydraulic Project Approval, issued 9-26-2011 23. 401 Water Quality Certification, issued January 8, 2013 24. Coastal Zone Management Certification, issued January 8, 2013 25. King County Clearing and Grading Permit, issued November 14, 2012 26. King County Flood Hazard Certification, approved December 12, 2011 27. National Marine Fisheries Services (NMFS) Concurrence on Endangered Species Act Section 7 Informal Consultation, 3-10-2011 Other 28. King County responses to comments on the Joint Public Notice, 12-7-2012 with attachments: h. See Item #8 (Post-Construction Erosion Monitoring Plan) i. See Item #7 (May Creek Phase 4 Monitoring Report) Page 2 of2 -•" .. - City of ReD11tOD11 lAND !USIE PIERM!T APPl!CAl!ON of Renton Planning Division May Creek Drainage Improvement Project Construction Mitigation Description 2-12-2013 FEB I 2 2013 Construction Schedule . fRf ~{(;~OW'~{Q) The project will be constructed in two phases. Sediment removal, vegetation removal, . and mitigation construction will occur within the first approved fish window after receiving the permit (likely 2013). Riparian and wetland plants will be installed during the following dormant season (November to February). Construction hours will be Monday through Friday between the hours of 7 a.m. to 7 p.m. Hauling/Transportation Routes Removed sediment will be dried onsite in the designated drying area on the east side of 148th Avenue SE (outside the city limits). After the material dries, it will be incorporated into adjacent pasturelands outside the designated floodplain and sensitive areas. Any material that is not incorporated onsite will be disposed of at an approved disposal site. Construction Best Management Practices The following measures will be used to minimize dust, traffic impacts, erosion, mud, noise, and impacts to sensitive areas. I. Noise: During construction, equipment operation will temporarily increase noise levels in the vicinity. Construction equipment may produce temporary noise levels as high as 90 decibels. To minimize noise impacts, construction activities will comply with provisions of the King County Noise Ordinance (Ordinance No. 3139). Equipment operation will be limited to the hours of 7 a.m. and 7 p.m., Monday through Friday. 2. Traffic Impacts: No traffic impacts are anticipated. Use of roadways for construction related work will have appropriate flaggers and safety measures in place prior to work commencing. 3. Erosion and Mud: During construction, erosion will be minimized by implementing appropriate sediment and erosion control best management practices. Measures will include a plan to divert flow from the stream reaches where the sediment and in-stream vegetation will be removed. Diverting the stream around the work area will minimize downstream water quality impacts. The plan will also limit all in-stream work to the summer low flow periods. In areas where invasive vegetation is removed from streams banks and replanted with native vegetation, best management practices will be implemented (e.g., silt fence, coir logs, etc.) to protect the stream during vegetation removal and installation. These measures are described in detail in the project's Construction Water Quality Protection and Monitoring Plan (King County September 2011) Page 1 of 2 • Ci~y off 1Rlsll1l~o1111 • ILANIDl ILDSIE IPIEIRlMnr AIPIPl!CAl!ON May Creek Drainage Improvement Project Construction Mitigation Description 2-12-2013 4. Dust: There will be low potential for the project to generate dust during transport of material, because the material being excavated and transported will be originating from the stream channel and wetland and will likely be moist. 5. Sensitive Areas: Construction equipment will use existing farm access roads, whenever possible to cross the wetland and floodplain. When wetland access is needed outside of existing farm roads, only rubber tired or tracked construction equipment will be allowed in the wetland and floodplain. This type of equipment can move across the landscape with minimal disturbance. 6. Sensitive Areas: Any wetland areas that are temporarily disturbed during construction will be restored with native wetland vegetation after construction is complete. To minimize the amount of temporary ground disturbance in the wetland, reed canarygrass will be removed from the planting areas using a weed barrier fabric instead of excavation. Native vegetation will be planted through the fabric. 7. Sensitive Areas: [n-stream vegetation removal will be completed by hand, when possible, to minimize turbidity in the stream and to avoid removing more vegetation than is necessary to restore flow conditions. When machine removal is required, the stream will be temporarily diverted around the work area as part of the temporary erosion and sediment control plan. Preliminary Traffic Control Plan A traffic control plan will not be available until a contractor is selected. After the contractor is selected for project construction, they will determine if a traffic plan is required. If a plan is required, the contractor will prepare it and provide it to the City for approval. Page 2 of 2 • KingCounty Water and Land Resources Division Department of Natural Resources and Parks King Street Center 201 South Jackson Street, Suite 600 Seattle, WA 98104-3855 . 206•296-6519 Fax 206-296-0192 nY Relay: 711 City of Renton Planning Division FEB 1 2 2013 Mitigated Determination of Non-Significance Date of Issue: September 8, 2010 Name of Proposal: May Creek Drainage Improvement Project (9Al205) Description of Proposal: King County's Water and Land Resources Division proposes to improve in-stream flow conditions along segments of May Creek in May Valley between approximately River Mile 4.3 and 4.9. Sediment accumulation and in-stream vegetation (e.g., · reed canarygrass and willows) throughout the valley reach of May Creek have been gradually decreasing channel flow capacity, causing a backwater effect. This is increasing the duration of flooding in actively used pastures on adjacent rural residential properties with flood conditions now persisting well into the summer months. The goal of this project is to reduce the duration of flooding on these properties at both the start and end of the rainy season by removing in-stream channel obstructions. This effort should help alleviate the duration oflocalized flooding on adjacent properties during low to moderate storm events and should allow the pastures to drain more effectively when flooding does occur. Due to the high groundwater table in the May Valley and because there will be no measureable difference in the geographic extent of flooding, it is not likely that this project will change the amount of wet pasture or wetland in the project vicinity. In addition, the project hydraulic analysis found that the potential for erosion downstream of May Valley is virtually unchanged for the pre-versus post-project conditions. Flow obstructing in-stream vegetation and accumulated sediment will be removed from the stream channel primarily using machinery operated from the stream bank. The vegetation and sediment removal will negatively impact existing in-stream fish habitat. Mitigation has been proposed to offset these impacts. Mitigation: The following mitigation will be implemented to avoid, minimize, and compensate for negative impacts to the in-stream and wetland habitat. o During construction, the stream flow will be diverted around the work area, and in-water work will only be conducted during the summer low flow when fish are less likely to be present. A King County biologist will be onsite during construction to monitor water quality. o Construction techniques, such as utilizing existing access roads or using temporary steel plates (or equivalent), where additional access is needed, will minimize disturbance to existing vegetation. In addition, direct access to the stream channel by equipment will only be allowed in specific areas where vegetation disturbance can be minimized. o Approximately 1.3 acres of wetland and riparian vegetation will be planted along May Creek (15 feet on each side of the stream from 148th Avenue SE upstream to the end of the project). Fencing will be installed to protect the plantings and the stream from livestock. 8/31120!0 • Mitigated Determination of Non-Significance May Creek Drainage Improvement Project Page 2 o Approximately 3.75 acres of wetland will be enhanced on the west side of 148th Avenue SE by removing invasive reed canarygrass and replanting with native wetland vegetation. Off- channel alcoves will also be excavated along May Creek in this location and large woody debris and streambed gravel will be added in the alcoves to enhance wetland fish habitat. o Fish habitat and natural stream processes will be restored at either the confluence of Long Marsh Creek and May Creek, or at another similar location in the project vicinity. Location of Proposal: The project is located in the May Valley near the cities of Renton and Newcastle (Sections 2 and 3, Township 23N, Range SE) on the south side of SE May Valley Road. The project area includes multiple segments of May Creek between approximately River Mile 4.3 (about 0.25 miles downstream of 148th Avenue SE in Renton) and River Mile 4.9. Re.1ponsible Official: Position/Title: Address: DATE: vf-1;'/0 Proponent and Lead Agency: Contact Person(.~): Mark Isaacson Division Director, Water and Land Resources Division 20 I South Jackson Street, Suite 600 Seattle, WA 981zp:: Jj SIGNATURE: ·-~P ' King County Department of Natural Resources and Parks Water and Land Resources Di vision Doug Chin, Project Manager, 206-296-8315 The lead agency for this proposal has determined that it does not have a probable significant adverse impact on the environment. An Environmental Impact Statement (EIS) is not required under Revised Code of Washington (RCW) 43.21 C.030(2)(c). This decision was made after review of a completed environmental checklist and other information on file with the lead agency. THIS INFORMATION IS AVAILABLE TO THE PUBLIC ON REQUEST (for a nominal photocopying fee). It is also available on the King County website at: http://www.kingcounty.gov/environment/watersheds/cedar-river-lake-wa/may-creek.aspx THIS MITIGATED DETERMINATION OF NON-SIGNIFICANCE (MONS) is issued under Washington Administrative Code (WAC) l 97-11-340(2). The lead agency will not act on this proposal until after September 22, 2010. Comments must be submitted or postmarked by that date. For additional information, please contact: Doug Chin, Project Manager King County Water and Land Resources Division 20 l South Jackson Street, Suite 600 Seattle, WA 98104-3855 (206) 296-83 15 Doug.Chin@kingcounty.gov 8131/20!0 • • Purpose of Checklist: KingCounty Environmental Checklist May Creek Channel Restoration Project The State Environmental Policy Act (SEPA), chapter 43.21 C RCW, requires all governmental agencies to consider the environmental impacts of a proposal before making decisions. An environmental impact statement (EIS) must be prepared for all proposals with probable significant adverse impacts on the quality of the environment. The purpose of this checklist is to provide information to help you and the agency identify impacts from your proposal (and to reduce or avoid impacts from the proposal, ifit can be done) and to help the agency decide whether an EIS is required. Instructions for applicants: This environmental checklist asks you to describe some basic information about your proposal. Governmental agencies use this checklist to detennine whether the environmental impacts of your proposal are significant, requiring preparation of an EIS. Answer the questions briefly, with the most precise information known, or give the best description you can. You must answer each question accurately and carefully, to the best of your knowledge. In most cases, you should be able to answer the questions from your own observations or project plans without the need to hire experts. If you really do not know the answer, or if a question does not apply to your proposal, write "do not know" or "does not apply." Complete answers to the questions now may avoid unnecessary delays later. Some questions ask about governmental regulations, such as zoning, shoreline, and landmark designations. Answer these questions if you can. If you have problems, the governmental agencies can assist you. The checklist questions apply to all parts of your proposal, even if you plan to do them over a period of time or on different parcels of land. Attach any additional information that will help describe your proposal or its environmental effects. The agency to which you submit this checklist may ask you to explain your answers or provide additional information reasonably related to determining if there may be significant adverse impact. Use of Checklist for Nonproject Proposals: Complete this checklist for nonproject proposals, even though questions may be answered "does not apply." IN ADDITION, complete the SUPPLEMENTAL SHEET FOR NONPROJECT ACTIONS (part D). For nonproject actions, the references in the checklist to the words "project," "applicant," and "property or site" should be read as "proposal," "proposer," and "affected geographic area," respectively. KING COUNTY ENVIRON£~T AL CHECKLIST May Creek Drainage Improvement Project A. BACKGROUND I. Name of proposed project, if applicable: May Creek Drainage Improvement Project (9 A 1205) 2. Name of applicant.· King County Department of Natural Resources and Parks Water and Land Resources Division 3. Address and phone number of applicant and contact person: 20 I South Jackson Street, Suite 600 Seattle, WA 98104-3855 Contact: Doug Chin, Project Manager Phone: (206) 296-8315 Fax: (206) 296-0192 Email: Doug.Chin@kingcounty.gov 4. Date checklist prepared: August 2010 5. Agency requesting checklist: King County Departmeni of Natural Resources and Parks Water and Land Resources Division 6. Proposed timing or schedule (including phasing, if applicable): The activities described in this. checklist are estimated to be completed in the summer of 2011, except for the planting which will be completed during the dormant season (approximately November 2011 to February 2012). The exact project schedule is dependent on when the necessary permits and property owner agreements are obtained. 7. Do you have any plans for future additions, expansion, or farther activity related to or connected with this proposal? lf yes, explain. Yes. The May Creek Basin Action Plan (King County 2001) and the May Creek Drainage and Restoration Plan (Geo Engineers Inc. 2008) make a series of recommendations to reduce flooding and improve habitat in May Valley. These include the removal of channel obstructions such as beaver dams, accumulated sediment, and vegetation choking the channel. This project addresses a subset of 2 KING COUNTY ENVIRO}.. .. ,ENT AL CHECKLIST May Creek Drainage Improvement Project the drainage improvements and restoration recommendations in these plans; additional recommended actions may be proposed as future projects. 8. List any environmental information you know about that has been prepared, or will be prepared, directly related to this proposal. · The following documentation has already been prepared and is directly related to this proposal: o May Creek Current and Future Conditions Report (King County and City ofRenton 1995) o May Creek Basin Action Plan (King County 2001) o May Creek Drainage and Restoration Plan (Geo Engineers Inc. 2008) o May Creek Erosion Stabilization Draft Report -May Creek Sediment Transport Study Phase 3 (Anchor QEA LLC 2010) o May Creek Wetland Delineation Report (King County 2010) o May Creek Baseline Stream Conditions (King County 2010) o May Creek Hydraulic Study (King County 2010) The following documentation has not yet been finalized for this project: o May Creek Stream and Wetland Mitigation Plan o May Creek Detailed Stream Habitat Survey o Effects Determination for Section 7 of the Endangered Species Act 9. Do you know whether applications are pending for governmental approvals of other proposals directly affecting the property covered by your proposal? If yes, explain. None are known to be pending. JO. List any government approvals or permits that will be needed for your proposal, if known. The following permits will likely be required for this project. The exact list of required permits will be determined based on feedback received from the regulatory agencies. o U.S. Army Corps of Engineers Section 404 Individual Permit o Compliance with Section 7 of the Endangered Species Act · o Compliance with Section 106 of National Historical Preservation Act o Washington Department of Ecology 401 Water Quality Certification o Washington Department of Ecology National Pollutant Discharge Elimination System Pennit o Washington Department offish and Wildlife Hydraulic Project Approval o King County ODES Clearing and Grading Permit o King County ODES Critical Area Alteration Exception o City of Renton Grade and Fill Permit o City of Renton Critical Areas Variance 3 KING COUNTY ENVIRONMCT AL CHECKLIST May Creek Drainage Improvement Project I I. Give brief, complete description of your proposal, including the proposed uses and the size of the project and site. There are several questions later in this checklist that ask you to describe certain aspects of your proposal. You do not need to repeat those answers on this page. King County's Water and Land Resources Division proposes to improve in-stream flow conditions along segments of May Creek in May Valley between approximately River Mile 4.3 and 4.9 .. Sediment accumulation and in-stream vegetation (e.g., reed canarygrass and willows) throughout the valley reach of May Creek have been gradually decreasing channel flow capacity, causing a backwater effect. This is increasing the duration of flooding in actively used pastures on 'adjacent rural residential properties with flood conditions now persisting well into the summer months. The goal of this project is to reduce the duration of flooding on these properties at both the start and end of the rainy season by removing in-stream channel obstructions. This effort should help alleviate the duration of localized flooding on adjacent properties during low to moderate storm events and should allow the pastures to drain more effectively when flooding does occur. Due to the high groundwater table in the May Valley and, because there will be no measureable difference in the geographical extent of flooding, it is not likely that this project will change the amount of wet pasture or wetland in the project vicinity. King County implemented a similar pilot project along 300 linear feet of May Creek in 2002 and, as a result, less overbank flooding now occurs during small stonn events along this reach. This project proposal consists of three components: vegetation removal, sediment removal, and stream/wetland mitigation. The vegetation and sediment removal will negatively impact existing in- stream fish habitat, so mitigation has been proposed to offset these impacts. The mitigation is also designed to improve the longevity of the project by decreasing the opportunity for channel obstructions to form in the future. The project components are described below. Vegetation Removal: The first component of the project includes removal of flow obstructing in- stream vegetation and debris from specific reaches where it is choking the channel and creating a backwater effect, causing flooding on adjacent properties during small storm events. Invasive reed canarygrass is the dominant vegetation that will be removed from the channel and banks. In addition, willows, located in multiple locations throughout the project area, are currently growing in the middle of the channel, further contributing to the backwater effect. A portion of the willows that are identified as obstructing flow will also be removed. The willows will be primarily removed by hand, but some small, hand-held, mechanized machinery may be used to assist. The reed canarygrass that is growing in the channel will be removed with machinery, most likely a trackhoe, operated from the stream bank. Prior to removal of the reed canarygrass, the stream will be diverted around the construction site and erosion and sediment control best management practices will be used during construction to minimize temporary downstream water quality impacts. Sediment Removal: Sediment will be removed from the stream channel using machinery, most likely a trackhoe, operated from the stream bank. The stream will be diverted around the construction site and erosion and sediment control best management practices will be used during construction to minimize temporary downstream water quality impacts. Construction techniques, such as utilizing existing access roads or using temporary steel plates (or equivalent) where additional access is needed, will be used to minimize temporary impacts to adjacent wetlands. 4 KING COUNTY ENVJROh«tENTAL CHECKLIST May Creek Drainage Improvement Project Stream/Wetland Mitigation: The final component of the project includes providing mitigation to avoid, minimize, and compensate for in-stream and wetland habitat impacts as well as implementing measures that will increase the longevity of the project. The following mitigation will be implemented: o During construction, the stream flow will be diverted around the work area, and in-water work will only be conducted during the summer low flow when fish are less likely to be present. A King County biologist will be onsite during construction to monitor water quality. o Construction techniques, such as utilizing existing access roads or using temporary steel plates ( or equivalent), where additional access is needed, will minimize disturbance to existing vegetation. In addition, direct access to the stream channel by equipment will only be allowed in specific areas where vegetation disturbance can be minimized. o A buffer of native vegetation (primarily wetland vegetation) will be restored for approximately 15 feet on each side of May Creek from 148th Avenue SE upstream to the eastern end of the project limits for a total of approximately 1.3 acres. This buffer is intended to shade out future reed canarygrass and to compensate for the cover that will be lost by removing flow obstructing willows and reed canarygrass. The native vegetation will be planted in areas where, under existing conditions, virtually no native vegetated buffer exists. In most of the project area, the regulatory stream buffer is contained within the delineated wetland boundary, which means that stream buffer enhancement could also be considered wetland enhancement. Fencing will be installed around the planting areas to minimize livestock access to the newly planted areas and to the stream. o Wetland enhancement will be performed by removing invasive vegetation within the wetland (mostly reed canarygrass) and replanting approximately 3.75 acres of native wetland vegetation in the open space tract on the west side of 148th Avenue SE. Off-channel alcoves will also be excavated along May Creek within the wetland in this location and.large woody debris will be added in the alcoves to partially compensate for the loss of in-stream habitat complexity that will occur as a result of removing flow obstructing vegetation. o Additional in-stream habitat restoration may occur at the confluence of Long Marsh Creek and May Creek. If implemented, this mitigation will restore fish habitat complexity at the confluence of these two streams. It wi II also restore the alluvial fan functions by removing the stream from the agricultural ditch and relocating it into a more natural channel, allowing sediment to drop out in Long Marsh Creek prior to reaching May Creek. If King County is unable to reach an agreement with the property owner to perform this mitigation, then similar mitigation will be proposed at another location either in the immediate project area or offsite. 5 KING COUNTY ENVIRONJ:'~TAL CHECKLIST May Creek Drainage Improvement Project 12. Location of the proposal. Give sufficient information for a person to understand the precise location of your proposed project, including a street address, if any, and section, township, and range, if known. ff a proposal would occur over a range of area, provide the range or boundaries of the site(s). Provide a legal description, site plan, vicinity map, and topographic map, if reasonably available. While you should submit any plans required by the agency, you are not required to duplicate maps or detailed plans submitted with any permit applications related to this checklist. The project is located in May Valley near the cities of Renton and Newcastle (Sections 2 and 3, Township 23N, Range SE) on the south side of SE May Valley Road. The project area includes the reach of May Creek between approximately River Mile 4.3 (about 0.25 miles downstream of 148th Avenue SE in Renton) and River Mile 4.9. Please see the attached vicinity map. B. ENVIRONMENTAL ELEMENTS 1. Earth a. General description of the site (circle one): jJgJ, rolling, hilly, steep slopes, mountainous, other. All of the proposed work will be completed within the May Valley, which is a flat, broad valley with little variation in elevation. The channel through this area has a very low gradient (0.2 percent slope), and as a result is prone to sediment accumulation. b. What is the steepest slope on the site (approximate percent slope)? The valley is flat with little variation across the floodplain. On both sides of the valley, the elevations rise quickly, with slopes ranging from 6 to 30 percent. c. What general types of soiis are found on the site (for example, clay, sand, gravel, peat, muck)? ff you know the classification of agricultural soils, specify them and note any prime farmland. The D_.S. Department of Agriculture National Resources Conservation Service Web Soil Survey (2009) for King County identifies Bellingham silt loam as the primary soil on the valley floor. At the higher elevations, adjacent to the valley, Ragnar-Indianola association and Alderwood gravelly sandy loam are _identified. Soil investigations during the wetland survey also found areas with a high concentration of clay. d Are there surface indications or history of unstable soils in the immediate vicinity? ff so, describe. There is no evidence of surface instability near the subject property. 6 KING COUNTY ENVIROh..tENTAL CHECKLIST May Creek Drainage Improvement Project e. Describe the purpose, type, and approximate quantities of any filling or grading proposed. Indicate source of fill. The purpose of this project is to remove channel obstructions from May Creek, including accumulated sediment and flow obstructing vegetation. Approximately 4,000 cubic yards of sediment will be excavated from May Creek. The removed sediment will either be disposed of appropriately offsite, or will be spread in an approved area adjacent to the project site in coordination with the property owner and as allowed by regulations and permits. As mitigation, the project proposes to restore approximately five acres of native vegetation (primarily wetland vegetation adjacent to the stream) through out the project area. This restoration will include shading out reed canarygrass using a sheet mulch treatment, such as cardboard or weed fabric, and replanting with native vegetation. In addition, approximately 76 pieces of large woody debris will be placed throughout the mitigation areas, and approximately 32 cubic yards of streambed gravel will be placed in off-channel alcoves west of 148th A venue NE. Streambed gravel will also be placed at the potentially restored confluence of Long Marsh Creek and May Creek, but the exact quantity at this location has not been determined yet. f Could erosion occur as a result of clearing, construction, or use? If so, generally describe. During sediment and in-stream vegetation removal, it is anticipated that some amount of sediment will likely be released into the stream. The sediment release will likely occur after in-channel construction work is complete and the diverted stream flow is reintroduced into freshly exposed stream bed and banks. g. About what percent of the site will be covered with impervious surfaces after project construction (for example, asphalt or buildings)? The project area currently does not contain any impervious surface, and the project will not add any impervious surface. h. Proposed measures to reduce or control erosion, or other impacts to the earth, if any: During construction, erosion will be minimized by implementing appropriate sediment and erosion control best management practices. Measures will include a plan to divert flow from the stream reaches where the sediment and in-stream vegetation will be removed. Diverting the stream around the work area will minimize downstream water quality impacts. The plan will also limit all in-stream work to the summer low flow periods. In areas where invasive vegetation is removed from streams banks and replanted with native vegetation, best management practices will be implemented ( e.g., 7 KING COUNTY ENVIRONJIT AL CHECKLIST • May Creek Drainage Improvement Project 2. Air silt fence, coir logs, etc.) to protect the stream during vegetation removal and installation. In the long-term, restoring a buffer of native vegetation will minimize erosion by providing long-term bank stabilization, while maintaining channel flow capacity. In addition, to determine whether there would be a significant erosion impact downstream as a result of the proposed project, King County assessed the pre-project versus post- project percentage of time ( over a 60-year period) that erosive flows would cause gravels to erode in the stream channel. The analysis found that, within the accuracy of the model being used, the percentage of time erosive flows occur is virtually unchanged for pre-versus post-project conditions. a. What types of emissions to the air would result from the proposal (i.e., dust, automobile, odors, greenhouse gases, industrial wood smoke) during construction and when the project is completed? ff any, generally describe and give approximate quantities if known. Construction of the proposed project may generate some dust during the transport of soil and sediment; however, because the material being transported will be originating from the stream channel and wetland, it will likely be moist, and therefore will have less potential to generate dust. The proposed project, once construction is complete, will emit no gasses with the potential to negatively affect climate change. Construction of the proposed project will use various vehicles and pieces of equipment that emit gasses with the potential to affect climate. These gasses include carbon dioxide (CO2), methane and nitrous oxide, as well as others in much smaller amounts. The global warming potential (GWP) of these compounds is measured in "carbon dioxide equivalents," or C02e, which converts the GWP of various gasses into their equivalent in CO2. The amount of C02e that may be emitted as a result of constructing the proposed project has been estimated by computing the amount of fuel to be consumed by equipment used to construct the project, both during construction and in transit from King County's Roads Maintenance Headquarters Shops in Renton, where crews and equipment may originate. The actual origin of equipment will not be known until after a contractor is selected. Fuel consumed is then converted into C02e emitted using formulae developed by the Energy Information Administration (EIA) of the U.S. Department of Energy. Using these formulae and estimates, construction of the proposed project will likely result in the discharge of approximately 12 tons ofC02e to the atmosphere. b. Are there any off-site sources of emissions or odor that may affect your proposal? ff so, generally describe. 8 KING COUNTY ENVIR01',.1ENT AL CHECKLIST May Creek Drainage Improvement Project No. c. Proposed measures to reduce or control emissions or other impacts to air. if any: 3. Water Greenhouse gas emissions will be controlled during construction by enforcing the King County Vehide Anti-Idling Policy. In addition, while not specifically proposed as mitigation for greenhouse gas emissions, the emissions will be offset by planting trees and shrubs that are an essential component of the proposed project. Trees and shrubs sequester CO2 during their growth and thus help to offset emissions of CO2 to the atmosphere. The EIA has also developed formulae for estimating the rate of carbon sequestration by various types of trees (deciduous or coniferous, fast-, medium-, or slow-growing) at various life stages and these formulae have been used to estimate the carbon sequestration potential of the proposed project. Approximately 680 trees will be planted during the planting season following construction of the proposed project. At rates calculated using the above method, these plantings should sequester the 12 tons of C02e emitted during construction of the proposed project in approximately 6.5 years. These calculations are attached to the checklist. In addition, construction will be performed in accordance with the regulations of the Puget Sound Clean Air Agency, and Best Management Practices for controlling fugitive dust will be utilized as necessary, and may include covering loads during transport and moistening material before transport. · a. Surface: I) ls there any surface water body on or in the immediate vicinity of the site (including year-round and seasonal streams, saltwater, lakes, pond~, wetlands)? If yes, describe type and provide names. If appropriate, state what stream or river ii flows into. Yes. The proposed project is within or immediately adjacent to May Creek, three small tributaries (Indian Meadow Creek, Long Marsh Creek, Greenes Creek), and one wetland (May Creek #5 in the King County Wetland Inventory). May Creek and its tributaries are Type F Waters ( containing fish or fish habitat) requiring 165 foot buffers under the King County Critical Area Code, and ultimately flow into Lake Washington. Under City of Renton Critical Area Code these streams are considered Class 2 streams ( salmonid bearing) and require a I 00 foot buffer. 9 KING COUNTY ENVIRONJ:~TAL CHECKLIST May Creek Drainage Improvement Project The May Creek #5 wetland is a large ( over 140 acres) riverine wetland that occupies much of the valley floor. Under the King County Critical Area Code this is a Category II wetland with a regulatory buffer of 110 feet. Under the City of Renton Critical Area Code this is a Category l wetland with a standard regulatory buffer width of I 00 feet. 2) Will the project require any work over, in, or a4Jacent to (within 200 feet) the described waters? If yes, please describe and attach available plans. Yes. Excess sediment and invasive reed canarygrass will be removed from the stream channel using a trackhoe or similar equipment. Access to these areas may require crossing the floodplain or wetland. Willows that are obstructing flow will also be removed, but primarily by hand. As mitigation for temporary impacts, any areas that are temporarily disturbed will be restored after construction by planting native vegetation. As mitigation for permanent impacts, a JS-foot buffer of native vegetation (primarily wetland vegetation) will be restored along both sides of the stream bank east of 148th Avenue SE where under existing conditions virtually no native vegetated buffer exists. A fence will be installed to protect the new plantings and to minimize livestock access to the stream. This vegetation will increase shade, add habitat, and minimize the return of the reed canary grass. On the west side of 148th Avenue SE, approximately 3.75 acres of riverine wetland will be enhanced. Off-channel alcoves with large woody debris will also be constructed on the west side of 148th Avenue SE to enhance fish habitat. In addition, natural alluvial fan functions and fish habitat will be potentially restored either at the confluence of May Creek and Long Marsh Creek or at another location with similar opportunity. 3) Estimate the amount of fill and dredge material that would be placed in or removed from surface water or wetlands and indicate the area of the site that would be affected. Indicate the source of fill material. Approximately 4,000 cubic yards of sediment will be removed from May Creek. The removed sediment will either be disposed of appropriately offsite, or will be spread in an approved pasture area adjacent to the project site in coordination with the property owner and as allowed by regulations and permits. As part of the mitigation, a sheet mulch treatment (e.g., cardboard or weed fabric) will be placed within the wetland boundary to shade out reed canarygrass and facilitate planting of native vegetation. Some compost may also be imported to facilitate planting, but the exact amount has not been determined yet. In addition, approximately 76 pieces of large woody debris will be placed throughout wetland west of 148th Avenue SE, and approximately 32 IO KING COUNTY ENVIR01-..,ENTAL CHECKLIST May Creek Drainage Improvement Project cubic yards of streambed gravel will be placed near the stream in the off- channel alcoves. Streambed gravel will also be placed at the potentially restored confluence of Long Marsh Creek and May Creek, but the exact quantity at this location has not been detennined yet. 4) Will the proposal require surface water withdrawals or diversions? Give general description, purpose, and approximate quantities if known. During the sediment and in-stream vegetation removal, the stream will be temporarily diverted around the work area as part of a temporary erosion and sediment control plan. This diversion may involve using one or more gas- . powered pumps to remove water from the channel just upstream of the work area. The water will then be discharged downstream of the work area. Any additional water that seeps into the construction work area may also be removed with a pump as needed. The stream diversion may require fish removal and relocation. All fish removal and relocations will be done by a King County biologist using hand-netting or other accepted methods. No other surface or groundwater will be withdrawn or diverted. 5) Does the proposal lie within a JOO-year floodplain? Ifso, note location on the site plan. Yes. The project area lies within the I 00-year floodplain for May Creek. 6) Does the proposal involve any discharges of waste materials to surface waters? If so, describe the type of waste and anticipated volume of discharge. No waste material will be discharged to surface or groundwater. b. Ground: I) Will ground water be withdrawn, or will water be discharged to ground water? Give general description, purpose, and approximate quantities if known. No. This project will not withdraw from or discharge to groundwater. 2) Describe waste material that will be discharged into the ground from septic tanks or other sources, if any (for example: Domestic sewage; industrial, containing the following chemicals ... ; agricultural; etc.). Describe the general size of the system, the number of such systems, the numb.er of houses to be served (if applicable), or the number of animals or humans the system(s) are expected lo serve. No waste material will be generated or discharged into the ground. II KING COUNTY ENVIRONMIT AL CHECKLIST May Creek Drainage Improvement Project c. Water runoff (including stormwater): I) Describe the source of runoff (including storm water) and method of collection and disposal, if any (include quantities, if known). Where will this water flow? Will this water flow into other waters? If so, describe. Any areas that are temporarily disturbed during construction have the potential to generate sediment-laden stonnwater runoff. Temporary erosion and sediment control best management practices, such as silt fences, turbidity curtains, or coir logs, will be used to prevent sediment-laden stormwater runoff from entering the stream or wetlands. As needed, additional best management practices may include collecting sediment-laden stonnwater before it enters the stream or wetland and discharging the stonnwater into a vegetated upland location instead. Water quality monitoring will be conducted during construction to ensure that state water quality standards are met. If water quality standards are exceeded, additional best management practices will be implemented to protect water quality. 2) Could waste materials enter ground or surface waters? If so, generally describe. No. All sediment excavated from the stream will be disposed of at an approved offsite location, or will be spread in an approved location adjacent to the project site in coordination with the property owners and as allowed by regulations and pennits. It will not be allowed to enter ground or surface waters. d. Proposed measures to reduce or control surface, ground, and runoff water impacts, if any: During construction, temporary erosion and sediment control best management practices, such as silt fences, turbidity curtains, or coir logs, will be used to prevent any material or runoff from entering ground or surface water during construction. Construction equipment access will also be limited to specific locations along the stream, which will minimize disturbance to existing vegetation. In the long-tenn, the purpose of this project is to reduce the duration of flooding in May Valley at both the start and end of the rainy season by removing in-stream channel obstructions. This effort should help alleviate the duration of localized flooding on adjacent properties during low to moderate stonn events. The project hydraulic analysis found that the potential for erosion downstream of May Valley is virtually unchanged for the pre-versus post-project conditions. 12 KING COUNTY ENVIROl'lu,IENT AL CHECKLIST May Creek Drainage Improvement Project 4. Plants a. Check or circle types of vegetation found on the site: [8:1 Deciduous Tree: alder, cottonwood, Oregon ash, maple, aspen, other -cherry [8:1 Evergreen Tree: fir, cedar, pine, other -spruce [8:1 Shrubs: willow, dogwood, hardhack, Indian plum [8:1 Grass: reed canarygrass [8:1 Pasture: various grasses D Crop or Grain: [8:1 Wet Soil Plants: cattail, buttercup, soft rush, bulrush, skunk cabbage, other -horsetail D Water Plants: water lily, eelgrass, mil foil, other [8:1 Other types of vegetation: blackberry b. What kind and amount of vegetation will be removed or altered? Approximately 3,000 square feet ofreed canarygrass will be removed from the stream banks. Approximately 5,500 square feet of flow obstructing willows will also be removed from the stream channel to improve flow conditions. In addition, approximately five acres of reed canarygrass will be removed adjacent to the channel and in the wetland and will be replanted with native vegetation. This reed canarygrass will be removed by placing a sheet mulch treatment, such as cardboard or weed fabric, over the grass to shade out the grass over multiple growing seasons. The native vegetation will be planted through this treatment. c. List threatened or endangered plant species known to be on or near the site. No threatened or endangered plant species are currently known to be on or near the project site; however, historically, threatened or endangered plant species were known to exist in the area. According to the Washington Department ofNatural Resources Washington Natural Heritage Program Database (June 2009), Tall Bugbane (Cimicifaga elata) existed historically in the project area but is not likely to be present any longer because it typically grows along the margins of mature or old growth stands of coniferous or mixed coniferous-deciduous forest. This type of habitat no longer exists in the project area. In addition, Tall Bugbane was not identified in the project study area during any of the wetland or stream surveys which spanned multiple days in January, February, and August 2010. 13 KING COUNTY ENVIRONJI.T AL CHECKLIST May Creek Drainage Improvement Project d. Proposed landscaping, use of native plants, or other measures to preserve or enhance vegetation on the site, if any: This project proposes to enhance five acres of native vegetation along the stream corridor and in the wetland. Invasive reed canarygrass will be removed along the stream and in the wetland, and the area will be replanted with native vegetation. 5. Animals a. Circle any birds and animals which have been observed on or near the site or are known to be on or near the site: [8] Birds: hawk, heron, eagle, songbirds, other: ducks [8] Mammals: deer, bear, elk, beaver, other: coyote [8] Fish: bass, salmon, trout, herring, shellfish, other b. List any threatened or endangered species known to be on or near the site. Terrestrial Species Red-tailed hawks (Buteo jamaicensis), bald eagles (Haliaeetus leucocephalus), and great blue herons (Ardea herodias) have been observed traveling through the project area; however, according to the Washington Department of Fish and Wildlife Priority Habitat and Species Database (June 2009) there are no documented or known nesting sites associated with these species in the project area. Great blue herons and bald eagles are both species of concern in Washington State (WDFW 20 JO), but are not threatened or endangered. Aquatic Species Historically, May Creek supported five species of salmonids: Chinook ( Oncorhynchus tshawytscha), sockeye (0. nerka), and coho (0. kisutch) salmon, as well as rainbow/steelhead ( 0. mykiss) and cutthroat ( 0. clarki) trout (King County 1995). Salmon still use May Creek and its tributaries even though their numbers have decreased (King County 1995). Chinook and sockeye salmon are found in the lower reaches of May Creek and in May Canyon; but they most likely do not travel upstream into May Valley as far as the project area (King County 1995). Both of these species are species of concern in Washington State (WDFW 20 I 0), and Chinook salmon is listed as threatened under the federal Endangered Species Act. Coho salmon and rainbow/steelhead and cutthroat trout rear in May Valley and use it as a travel corridor to upstream spawning habitat in the North Fork, Cabbage and Country Creeks, and Tributary 0291 A (King County 1995). Under the federal Endangered 14 KING COUNTY ENVIROl'\,,1ENTAL CHECKLIST May Creek Drainage Improvement Project Species Act, steelhead are listed as a threatened species, and coho salmon are a species of concern. In addition, the Lake Washington Basin contains spawning populations of the federally- listed threatened bull trout (Salvelinus conjluentus), but no spawning populations have been confirmed in the part of the basin where the project is located (WDFW 1998, 2004a). Furthermore, it is unlikely bull trout will be present in May Creek due to a lack of suitable habitat. Under the federal Endangered Species Act, no designated or proposed critical habitat for Chinook salmon, steelhead, or bull trout is located within the project area. An effects determination for species protected under Section 7 of the Endangered Species Act will be completed in coordination with the appropriate federal agencies during the permitting process. This detennination will analyze potential impacts to listed species resulting from the project. c. Is the site part of a migration route? If so, explain. Yes. Anadromous fish, including coho salmon, rainbow/steelhead and cutthroat trout, use the May Valley as a migration corridor to upstream spawning habitat. Most of the large valleys in King County, including May Valley, comprise a portion of the Pacific Flyway used by waterfowl and other migratory bird species during spring and fall migration. d. Proposed measures to preserve or enhance wildlife, if any: Best management practices will be utilized during construction to minimize potential impacts to listed species. For example, in-water construction work will be completed during the summer low flow work window that is designated to protect listed aquatic species. Species are unlikely to be present in the project area during the designated summer work window. Temporary erosion and sediment control measures ( discussed in section 3.c above), including a stream diversion, will also be implemented to protect water quality. The stream diversion may require fish removal and relocation. All fish removal and relocations will be done by a K,ing County biologist using hand-netting or other accepted methods. In the long-term, this project will enhance fish and wildlife habitat in May Valley by restoring approximately five acres of native wetland and riparian vegetation, adding large woody debris to off-channel alcoves, and potentially restoring fish habitat and alluvial fan functions at the confluence of Long Marsh Creek and May Creek. This will increase the complexity and diversity of habitat available in the project area. 15 KING COUNTY ENVIRONJITAL CHECKLIST • May Creek Drainage Improvement Project 6. Energy and Natural Resources a. What kinds of energy (electric, natural gas, oil, wood stove, solar) will be used to meet the completed project's energy needs? Describe whether it will be used for heating, manufacturing, etc. None. The completed project will not require any energy. b. Would your project affect the potential use of solar energy by adjacent properties? If so, generally describe. No. c. What kinds of energy conservation features are included in the plans of this proposal? List other proposed measures to reduce or control energy impacts, if any: None are proposed. 7. Environmental Health a. Are there any environmental health hazards, including exposure to toxic chemicals, risk of fire and explosion, spill, or hazardous waste, that could occur as a result of this proposal? If so, describe. No toxic chemical or hazardous waste will be used or generated by this project. 1) Describe special emergency services that might be required. None. 2) Proposed measures to reduce or control environmental health hazards, if any: Maintenance and refueling of construction equipment will occur outside of the stream, wetland, and buffer areas. b. Noise 1) What types of noise exist in the area which may affect your project (for example: traffic, equipment, operation, other)? Some minor traffic noise from adjacent roads is expected, but it will have no effect on construction or on the completed project. 16 KING COUNTY ENVIRO.l\,.1ENTAL CHECKLIST May Creek Drainage Improvement Project 2) What types and levels of noise would be created by or associated with the project on a short-term or a long-term basis (for example: traffic, construction, operation, other)? Indicate what hours noise would come from the site. During construction, equipment operation will temporarily increase noise levels in the vicinity. Construction equipment may produce temporary noise levels as high as 90 decibels. The completed project will not change existing noise levels. 3) Proposed measures to reduce or control noise impacts, if any: Construction activities will comply with provisions of the King County Noise Ordinance (Ordinance No. 3139). Equipment operation will be limited to the hours of7 a.m. and 7 p.m., Monday through Friday. 8. Land and Shoreline Use a. What is the current use of the site and adjacent properties? The current use of the site is a combination of rural residential with small farms and undeveloped open space. The small farms in the project area primarily consist of pastures that are utilized by horses. b. Has the site been used for agriculture? Ifso, describe. Yes. May Valley supports pasture and low-intensity agriculture uses, small farms, and scattered single-family residences; however, the project area is not located in an Agriculture Production District. Historically, May Valley was probably more extensively utilized for agriculture production; however, under existing conditions the pastures in the project area are primarily utilized only by horses. c. Describe any structures on the site. The adjacent properties contain single-family homes, barns, and other out-buildings. None of these structures will be affected by construction of the proposed project. d. Will any structures be demolished? If so, what? No. e. What is the current zoning classification of the site? The current zoning classification is RA-5 and RA-l 0, rural residential with future development limited to rural uses with maximum densities of one house per five aces and ten acres, respectively. 17 KING COUNTY ENVIRONJliT AL CHECKLIST • May Creek Drainage Improvement Project f What is the current comprehensive plan designation of the site? The current comprehensive plan designation is rural residential. g. If applicable, what is the current shoreline master program designation of the site? Not applicable. May Creek is not a Shoreline of the State in the project area and therefore, is not regulated under the King County Shoreline Master Program. h. Has any part of the site been classified as an "environmentally sensitive" area? If so, specify. Yes. The proposed project will occur in and adjacent to May Creek and its tributaries, which are Type F Waters ( contains fish or fish habitat) under the King County Critical Area Code. The proposed project is also located in the l 00-year floodplain for May Creek. In addition, a large Category II Wetland (May Creek #5) covers a large percentage of the May Valley floor. The proposed work will all occur within the stream, wetland, buffers, and floodplain of May Creek. i. Approximately how many people would reside or work in the completed project? None. j. Approximately how many people would the completed project displace? None. k. Proposed measures to avoid or reduce displacement impacts, if any: Does not apply. I. Proposed measures to ensure the proposal is compatible with existing and projected land uses and plans, if any: One of the project goals is to reduce the duration of flooding on properties adjacent to May Creek. Reducing floodwaters on these properties will facilitate the continued use of these properties as single-family homes with small farms. 18 KING COUNTY ENVIR01 ... ,ENT AL CHECKLIST May Creek Drainage Improvement Project 9. Housing a. Approximately how many units would be provided, if any? Indicate whether high, middle, or low-income housing. Does not apply. b. Approximately how many units, if any, would be eliminated? Indicate whether high, middle, or low-income housing. Does not apply. c. Proposed measures to reduce or control housing impacts, if any: Does not apply. 10. Aesthetics a. What is the tallest height of any proposed strncture(s), not including antennas; what is the principal exterior building material(s) proposed? Does not apply. No buildings or structures will be constructed. b. What views in the immediate vicinity would be altered or obstructed? None. c. Proposed measures to reduce or control aesthetic impacts, if any: Does not apply. 11. Light and Glare a. Whal type of light or glare will the proposal produce? What time of day would it mainly occur? None. b. Could light or glare from the finished project be a safety hazard or interfere with views? No. 19 KING COUNTY ENVIRONATAL CHECKLIST • May Creek Drainage Improvement Project c. What existing off-site sources of light or glare may affect your proposal? None. d. Proposed measures to reduce or control light and glare impacts, if any: Does not apply. 12. Recreation a. What designated and informal recreational opportunities are in the immediate vicinity? Recreational opportunities in the immediate project area are limited; however, they could include fishing, hiking, bicycling, and/or bird watching. Within a couple of miles of the project area, the King County Cougar Mountain Park and the Squak Mountain State Park together provide over 5,000 acres of public land with trails for hiking and horseback riding. b. Would the proposed project displace any existing recreational uses? Ifso, describe. No. All of the proposed work will occur on private property and will not affect recreational opportunities or access. c. Proposed measures to reduce or control impacts on recreation, including recreation opportunities to be provided by the project or applicant, /{ any: No measures proposed. 13. Historic and Cultural Preservation a. Are there any places or objects listed on, or proposed for, national, state, or local preservation registers known to be on or next to the site? If so, generally describe. The Washington State Department of Archaeology and Historic Preservation and the King County Cultural Resource Protection Project databases were checked on March 1, 2010. No listed or proposed historic properties or archaeological sites were found in the project vicinity. b. Generally describe any landmarks or evidence of historic, archaeological, scientific, or cultural importance known to be on or next to the site. None are known to be present. c. Proposed measures to reduce or control impacts, if any: 20 KING COUNTY ENVIROl'.atENT AL CHECKLIST May Creek Drainage Improvement Project Because there are not any listed or proposed archaeological or historic resources in the project area, no mitigation is being proposed. If, archaeological or historic resources are uncovered or encountered during project construction, work will cease immediately, and appropriate steps necessary to protect those resources will be taken before construction resumes. If resources are discovered, the Washington State Department of Archaeology and Historic Preservation, the King County Historic Preservation Program, and any affected federally recognized tribes will be notified immediately, and an on-site inspection will be conducted by a professional archaeologist and other qualified resource professionals. A mitigation plan would then be prepared before resuming construction at the site of discovery, if necessary. In addition, the measures and the possibility of uncovering materials of archaeological or historic significance near inland waters will be discussed during a preconstruction conference with the construction crew/contractor before performing the work on-site. 14. Transportation a. Identify public streets and highways serving the site, and describe proposed access to the existing street system. Show on site plans, if any. Access to the site will be from properties located on SE May Valley Road or 148th Avenue SE. b. Is site currently served by public transit? If not, what is the approximate distance to the nearest transit siop? Does not apply. c. How many parking spaces would the completed project have? How many would the project eliminate? Does not apply. d. Will the proposal require any new roads or streets, or improvements to existing roads or streets, not including driveways? If so, generally describe (indicate whether public or private). No new roads will be required. e. Will the project use (or occur in the immediate vicinity of) water, rail, or air transportation? If so, generally describe. No. 21 KING COUNTY ENVIRONJI\TAL CHECKLIST May Creek Drainage Improvement Project f How many vehicular trips per day would be generated by the completed project? If known, indicate when peak volumes would occur. None. g. Proposed measures to reduce or control transportation impacts, if any: Does not apply. 15. Public Services a. Would the project result in an increased need for public services (for example: fire protection, police protection, health care, schools, other)? If so, generally describe. No. b. Proposed measures to reduce or control direct impacts on public services, if any. Does not apply. 16. Utilities a. Circle utilities currently available at the site: electricity, natural gas, water, refuse service, telephone, sanitary sewer, septic system, other. Does not apply. b. Describe the utilities that are proposed for the project, the utility providing the service, and the general construction activities on the site or in the immediate vicinity which might be needed Does not apply: 22 KING COUNTY ENVIRONMENTAL CHECKLIST May Creek Drainage Improvement Project C. SIGNATURE The above answers are true and complete to the best of my knowledge. I understand that the lead agency is re~ying 011 them to make its decision. Signature: _---=...!W!.Wr~~~iu~/t~e-z~.ik~'------------- Name: Wally Archulet/. P.E. Title: Mana~inJ?i Bn~•ineer, Department of Transportation, Road Services Division, Environmental Unit Date: ~ l 1~L IO I The following are included with the Checklist if checked off: ~ Vicinity Map ~ Greenhouse Gas Worksheet D Project Plans 23 May Creek Drainage Improvement Project (9A 1205) Legend 0 Project Area Limits City Boundaries o RiverMiles The lnlormetion lnduded on this map has been complied by IOng County staff from a variety of sources and Is subject to ehangc, without nolim. King County makes oo representations or warranties, expn,ss « ~ed. as lo ac:curacy, completeness, limelness, or rights lo Iha use of sud! imormatlon. This dorumenl is not Intended for use as a Wl'll!IY produd.. King County shal not be liable for errt general, special. indireel, inodental, or a:nseQU11nlilll d8mages inclucllng, but not limited to, lost revenues or lost profits resulUng from Iha use or misuse of lhe inklrmsllon COIU81ned on this map. My sale of this map or Information on lhis map is prohibited except by written permission of King Courrty. ~-:;,~.·· " ,. . . :;,; " . . . ~~;;;...,., -· - Greenhouse Gas (GHG) Emissions Worksheet Project Name: May Creek Drainage Improvement Project (9A1205) Note: The finished project will emit no GHGs aside form those occuring in the environment by natural processes. All emissions are therefore related to construction of the proposed project. Distance of project site from Renton Shops, where most daily construction-related vehicle trips will start and end: Estimated days of construction activity: 1..:l 1..:co __ --' Vehicle Pickup Pickup Dump Truck Dump Truck PC 120 Trackhoe Heavy Equip Transport Log Truck TOTAL: Carbon Sequestration Miles/ hours 40 40 160 160 160 40 16 Rate (mpg or gal/hr*) Fuel Used 20.7 1.93 20.7 1.93 6.15 26.02 6.15 26.02 6.3 1008.00 1.9 21.05 1.9 8.42 3.75 miles Em. Coe!. (lbs C02e/ gal) Emissions 19.564 19.564 . 22.384 22.384 22.384 22.384 22.384 (lbs C02e) Tons C02e 37.80 0.02 37.80 0.02 582.35 0.29 582.35 0.29 22563.07 11.28 471.24 0.24 188.50 0.09 24463.12 12.23 Approximately 680 trees will be planted as part of this project. Of these, 340 as classified as fast- growing hardwoods, and the remaining 340 as moderate-growing conifers. The carbon sequestration rates of these trees was calculated using data tables from the U.S. Department of Energy, Energy Information Administration. Using these data tables, the proposed plantings (assuing an 80% survival rate) will sequester 10.9 tons of carbon after 6 years and 14.0 tons after 7 years. ·• STATE OF WASHINGTON DEPARTMENT OF ECOLOGY Northwest Regional Office • 3190 160th Ave Sf• Bellevue, WA 98008-5452 • 425-649-7000 711 for Was/1i11gto11 Relay Service • Perso11s with ,1 speech ,lisability ca11 .call 877-833·ffj January 8, 2013 . Play ?f Renton Doug Chin, Project Manager King County Water and Land Resources Division 201 South Jackson Street, Suite 600 Seattle, WA 98104-3855 nnmg Division FEB 1 2 Z013 RE: Water Quality Certification Order #9352 for U.S. Army Corps of Engineers Public Notice #NWS-2010-158, May Creek Drainage Improvement Project, in Renton, King County, Washington Dear Mr. Chin: On June 20, 2012, King County Water and Land Resources Division submitted a Joint Aquatic Resource Permit Application (JARP A) to the Department of Ecology (Ecology) for a Section 401 Water Quality Certification (401 Certification) under the federal Clean Water Act for the above project. On behalf of the State of Washington, Ecology ce1iifies that the work described in the JARPA and the public notice complies with applicable provisions of Sections 301,302, 303, 306 and 307 of the Clean Water Act, as amended, and applicable state laws. This ce1iification is subject to the conditions contained in the enclosed Order. If you have any questions, please contact Rebekah Padgett at (425) 649-7129. The enclosed Order may be appealed by following the procedures described in the Order. Sincerely, 'b/it--~JJ.-- Erik Stockdale, Unit Supervisor Northwest Regional Office Sho1·elands and Environmental Assistance Program ES:rrp:cja Enclosure By certified mail: 7012 1640 0000 6245 9597 Doug Chin January 8, 20 l3 Page 2 of2 • cc: Lori Lull, U.S. Almy Corps of Engineers • Lany Fisher, Washington Department of Fish and Wildlife Karen Walter, Mucldeshoot Indian Tribe Katie Bonwell e-cc: Patrick McGraner -NWRO Patricia Olson -HQ Loree' Randall -HQ Raman Iyer -NWRO ecyrefedpennits@ecy.wa.gov Jennifer Henning, City of Renton Jhenning@Rentonwa.gov Karen Walter, Muckleshoot Indian Tribe KWalter@muckeshoot.nsn.us Jean Rollins urbanseparator@hotmail.com Debra Rogers herogers@comcast.net Susan Malin susiemalin@msn.com Gary Amundson gary.a@comcast.net Andrew Duffus klassicars@hotmail.com Carol Tabacek caroltabacek@aol.com Mary Weirich maryyweirich@comcast.net A. Dufft1s blueheron6987@hotmail.com Julie Bonwell jbonwell@lesourd.com Mary Celigoy maryceligoy@comcast.net • • IN TIIE MATTER OF GRANTING A ) WATER QUALITY ) CERTIFICATION TO ) KINGCOUNTYWATERANDLAND.) RESOURCES DIVISION ) in accordance with 33 U.S.C. 1341 (FWPCA § 401), RCW 90.48.120, RCW 90.48.260 and Chapter 173-201A WAC TO: Doug Chin, Project Manager ) ) ) ORDER#9352 Corps Reference #NWS-2010-158 May Creek Drainage Improvement Project; Renton, King County, Washington. King County Water and Land Resources Division 20 l South Jackson Street, Suite 600 Seattle, WA 98104-3855 On June 20, 2012, King County Water and Land Resources Division submitted a Joint Aquatic Resources Permit Application (JARPA) to the Department of Ecology (Ecology) for a Section 401 Water Quality Certification. A joint public notice regarding the request was distributed by the U.S. Army Corps of Engineers (Corps) for the above-referenced project pursuant to the provisions of Chapter 173-225 WAC on September 26, 2012. The drainage improvement work includes: o Dredging: Remove sediment from 2,086 linear feet of the creek. A temporary access road includes placement of quarry spalls in 7,550 square feet of wetland, and replanting with native vegetation upon removal. o Vegetation Removal: Clear reed canarygrass and willows from 14,500 square feet of channel. o Sediment Management: Reconstruct 300 feet of Long Marsh Creek Channel and its confluence with May Creek for sediment storage, including excavation of 290 cubic yards of material. Create a JOO-foot side channel parallel to May Creek and joining Long Marsh.Creek. Mitigation for impacts to the creeks, permanent fill of approximately 0.48 acre of Category 2 wetland, and temporary fill of approximately 7,550 square feet of Category 2 wetland includes: o Installati.on of a 15-foot buffer of native riparian and wetland planting on both sides of May Creek (total of2.0 acres), an I I-foot buffer of native riparian planting on both sides of Long Marsh Creek, and a 6-to 8-foot buffer of native riparian planting on the north side of the side channel. Fencing will be installed around the planting areas to minimize livestock access to the stream. o Enhancement of approximately 3 acres of wetland which would include construction of off-channel wetland alcoves along May Creek, reed canarygrass suppression, installation of 16 pieces of large woody debris and two snags in the off-channel wetland alcoves, placement of 45 cubic yards of streambed gravels in the reconstructed 300 linear feet of • Order #9352, .ps Refere11ce # NWS-2010-158 Kf11g Cou/1/y Waler and La11d Resources Division Jm,ua,y8. 2013 Page2 o/19 Long Marsh Creek, placement of 60 pieces of large woody debris in the wetland enhancement area, and planting of native vegetation. The project is located both upstream and downstream of the 148 1h Avenue SE bridge in Renton, King County, Washington, May Creek and wetlands, Sections 2 and 3, T. 23 N., R. SE., WR1A 8. AUTHORITIES: In exercising authority under 33 U.S.C. § 1341, RCW 90.48.120, and RCW 90.48.260, Ecology has examined this application pursuant to the following: 1. · Confo11nance with applicable water quality-based, technology-based, and toxic or pretreatment effluent limitations as provided under 33 U.S.C. §§ 1311, 1312, 1313, 1316, and 1317 (FWPCA §§ 301,302,303,306 and 307); 2. Conformance with the state water quality standards contained in Chapter 173-201A WAC and authorized by 33 U.S.C. § 1313 and by Chapter 90.48 RCW, and with other applicable state laws; and 3. Conformance with the provision of using all known, available and reasonable methods to prevent and control pollution of state waters as required by RCW 90.48.010. WATER QUALITY CERTIFICATION CONDITIONS: Through issuance of this Order, Ecology ce1tifies that it has reasonable assurance that the activity as proposed and conditioned will be conducted in a manner that will meet the applicable water quality standards and other appropriate requirements of state law. In view of the foregoing and in accordance with 33 U.S.C. § 1341, RCW 90.48.120, RCW 90.48.260 Chapter 173-200 WAC and Chapter 173-20 lA WAC, water quality certification is granted to the Applicant subject to the conditions within this Order. · · Certification of this proposal does not authorize the Applicant to exceed applicable state water quality standards (Chapter 173-201 A WAC), ground water standards (Chapter 173-200 WAC) or sediment quality standards (Chapter 173-204 WAC). Furthermore; nothing in this certification shall absolve the Applicant from liability for contamination and any subsequent cleanup of smface waters, ground waters or sediments occul1'ing as a result of project construction or operations. • A. General Conditions: Order #9352, ~o,ps Reference# NWS-2010-158 King County Water and Land Resources Division January 8, 20 J 3 Page3 o/19 Al. For purposes of this Order, the term "Applicant" shall mean King County Water and Land Resources Division and its agents, assignees and contractors. A2. For purposes of this Order, all submittals required by its conditions shall be sent to Ecology's Northwest Regional Office, Attn: 401/CZM Federal Project Manager, 3190 1601h Avenue SE, Bellevue, WA 98008-5452. Any submittals shall reference · Order #9352 and Corps Reference #NWS-2010-158. A3. Work authorized by this Order is limited to the work described in the JARPA received by . Ecology on June 20, 2012. The Applicant will be out of compliance with this Order and must reapply with an updated application if the information contained in the JARPA is voided by subsequent changes to the project not authorized by· this Order. A4. Within 30 days ofreceipt ofan updated JARPA, Ecology will determine if the revised project requires a new water quality cel1ification and public notice or if a modification to this Order is required. AS. This Order shall be rescinded if the U.S. Army Corps of Engineers does not issue an individual Section 404 pe11nit. A6. Copies of this Order shall be kept on the job site and readily available for reference by Ecology personnel, the construction superint~ndent, constrnction managers and lead workers, and state and local government inspectors. A 7. The Applicant shall provide access to the project site and all mitigation sites upon request by Ecology personnel for site inspections, monitoring, necessary data collection, and/or to ensure that conditions of this Order are being met. AS. Nothing in this Order waives Ecology's authority to issue· additional ,orders if Ecology determines that fi.nther actions are necessary to implement the water quality laws of the state. Fmther, Ecology retains continuing jurisdiction to make modifications hereto through supplemental order, if additional impacts due to project construction or operation are identified (e.g., violations of water quality standards, downstream erosion, etc.), or if additional conditions are necessary to further protect water quality. A9. The Applicant shall ensure that all appropriate project engineers and contractors at the project site have read and understand relevant conditions of this Order and all permits, approvals, and documents·referenced in this Order. The Applicant shall provide Ecology a signed statement (see Attachment A for an example) from each project engineer and · contractor that they have read and understand the conditions of this Order and the above- • n Order #9352, ,.,.,rps Reference# Nll'S-2010-158 King Co1111ty Water and Land Resources Division January 8, 20 I 3 Page4 o/19 referenced permits, plans, documents and approvals. These statements shall be provided to Ecology before constrnction begins at the project or mitigation sites. A 10. This Order does not authorize direct, indirect, permanent, or temporary impacts to waters of the state or related aquatic resources, except as specifically provided for in conditions of this Order. · A 11. Failure of any person or entity to comply with this Order may result in the issuance of civil penalties or other actions, whether administrative or judicial, to enforce its terms. B. Wetland Compensatory Mitigation: B 1. · The Applicant shall mitigate wetland impacts as described in the May Creek Drainage Improvement Project (9Al 205) -King County Water and Land Resources Division - Stream and Wetland Impact Analysis and Mitigation Plan prepared by King County Road Services Division for King County Depa11ment ofNaturnl Resources and Parks, dated Revised September 2011 and including the Long Marsh Cl'eek Restol'ation Project - Basis of Design Report prepared by King County Water and Land Resources Division, . dated September 14, 2011 (hereafter collectively called the "Mitigation Plan") 01· as modified by this Order or revised and approved by Ecology. B2. The Applicant shall submit any changes to the Mitigation Plan in writing to Ecology (see A2) for review and approval before work begins. B3. · The Applicant shall get review and written approval from Ecology of any plan changes • • required if problems arise during constmction and planting of the wetland mitigation site. B4. The Applicant shall have a wetland professional at the wetland mitigation site during construction and planting. Implementation BS. Unless otherwise approved by Ecology in writing, the Applicant shall begin the compensatory mitigation project before, or concutrent with, impacting wetlands or Ecology may require additional compensation to account for additional tempornl loss of wetland functions. B6. If the mitigation site(s) cannot be completed within 13 months of the date of this Order, the Applicant shall inform Ecology, in writing, of the status of a) May Creek Drainage Improvement Project, and b) May Creek and Long Marsh Creek restoration sites. With the: c) Reason for the delay. d) Expected date of completion. Order #9352, ._orps Reference# NWS-2010-158 King County Water and Land Resources Divls/011 Jam,ary 8, 2013 Page5 o/19 The Applicant shall submit an updated written notification every 12 months thereafter until the May Creek Drainage Improvement Project and May Creek and Long Marsh Creek Restoration restoration sites are complete. · B7. The Applicant shall ensure that all excess excavated site material is disposed of in an appropriate location oi1tside of wetlands and their buffers at the wetland mitigation site and above the 100-year floodplain. BS. The Applicant shall ensure that no material is stockpiled within existing wetlimds and their buffers at the wetland mitigation site(s) at any time, unless provided for in the Ecology-approved Mitigation Plan. B9. The Applicant shall ensure that no construction debris is deposited within existing wetland and their buffers at the wetland mitigation site at any time, unless provided for in the Ecology approved Mitigation Plan. BI 0. The Applicant shall not use Polyacrylamide on exposed or disturbed soil at the mitigation site(s). B 11. The Applicant shall not use hay or straw on exposed or disturbed soil at the mitigation site(s). B 12. If seeding is used at the wetland mitigation site, the seed mix must contain native, annual, non-invasive plant species. BJ3. The Applicant shall place signs at the mitigation areas' boundaries, including buffers, every 150 feet to mark the areas as wetland mitigation sites. B 14. Upon completion of site-grading and prior to planting, the Applicant shall submit to Ecology written confirmation that the finished grades are consistent with the approved · Mitigation Plan or subsequent Ecology-approved plan changes. Written confirmation can be in the form of a signed letter from the smveyor or project engineer indicating how final elevations were confirmed and whether those elevations are consistent with the Mitigation Plan. B 15. Within 90 days of completing construction and planting of the mitigation site(s), the Applicant shall submit to Ecology (see A2) one hard copy and one electronic file of the final as-built report including maps. The as-built report must: a) Document site conditions at Year Zero. Order #9352,,ps Reference# NWS-2010-158 King County Water and land Resources Division Janum)' 8, 2013 Page6 o/19 b) Include the infmmation listed in Attachment B (Infonnation Required for As-built Reports). c) Include documentation of the recorded legal mechanism required in Condition B16. B16. Within 90 days of completing construction and planting of the May Creek and Long Marsh Creek restoration sites, the Applicant shall record a Wetlands Notice (see Attachment C: Wetland Notice for Deed Notification). The Notice must be recorded with the County Recording Office, Registrar of Deeds, or other official responsible for maintaining records for, or interest in, real prope11y. This requirement does not apply to that po1tion of the mitigation that is to occur within the Stonegate Open Space Tract. Monitoring and Maintenance B 17. The Applicant shall water and maintain all mitigation site plantings so as to meet the Mitigation Plan's perfo1mance standards (Section 6). B18. The Applicant shall monitor the mitigation site for a minimum of 10 years. The Applicant shall use the monitoring methods described on pages 27 and 28 of the Mitigation Plan (Section 6). 819. The Applicant shall submit to Ecology (see A2) one hard and one electronic copy of monitoring repo1ts docmnenting mitigation site conditions for years 1, 2, 3, 5, 7, and 10. At a minimum, the reports must contain the information in Attachment D (Information Required for Monitoring Reports). The Applicant shall submit the first monitoring report 12 months after completing the mitigation site construction and planting. B20. The Applicant shall implement the Mitigation Plan's contingency measures if the Mitigation Plan's goals, objectives, or perfonnance standards are not being met. B21. Prior to implementing contingency measures not specified in the Mitigation Plan, the Applicant shall consult with and obtain written approval from Ecology for the changes. B22. When necessruy to meet the perfmmance standards, the Applicant shall replace dead or dying plants with the srune species, or an appropriate native plant alternative, during the first available planting season and note species, numbers, and approximate locations of all replacement plants in the subsequent monitoring report. B23. At the end of the monitoring period, the Applicant shall use the August 2004 or updated version of"Washington State Wetlands Rating System for Western Washington" to rate the wetland within the Stonegate Open Space Tract downstream ofthe148th Ave SE bddge and include the information in the monitoring report. Order #9352, ~vrps Reference #NWS-20/0-/58 King County Water and land Resources Division January• 8, 20 I 3 Page? o/19 B24. If the Applicant has not met all conditions and performance standards for the mitigation site at the end of the monitoring period, Ecology may require additional monitoring, additional mitigation, or both. B25. Until the Applicant has received written notice from Ecology that the Mitigation Plan has been fully implemented, the Applicant's obligation under Condition Bl to mitigate for wetland impacts is not met. C. Water Quality Coudition: Cl. May Creek is classified as "Salmonid Spawning, Rearing, and Migration" and the criteria of that class apply except as specifically modified by this Order. This Order does not authorize temporary exceedances of water quality sfandards beyond the limits established in WAC 173-201A-200(1)(e)(i). C2. · The Applicant shall implement the May Creek Drainage Improvement Project (9A 1205) Construction Water Quality Protection and A1onitoring Plan (hereafter called t.he "Water Quality Plan") prepared by King County Department of Natural Resources and Parks Water and Land Resources Division, revised September 7, 2011, or as modified by this Order or revised and approved by Ecology. C3. The Applicant shall submit any changes to the Water Quality Plan in writing to Ecology (see A2) for review and approval before work begins. n. Conditions for Construction Activities: Gene1·al Conditions: DI. Applicant shall comply with Construction Stormwater General Permit #W AR-124978 for this project. D2. Construction stormwater, sediment, and erosion control best management practices (BMPs; e.g., filter fences, etc.) suitable to prevent exceedances of state water quality standards shall be in place before starting construction at the site. D3. Sediment and erosion control measures shall be inspected and maintained prior to and during project implementation. D4. All construction debris shall be properly disposed of on land so that it cannot enter a waterway or cause water quality degradation to state waters. r Order #9352, .... ~,ps Reference# NWS-2010-158 King County Water and Land Resources Division Jan1101y 8, 2013 Page 8 o/19 D5. Machinecy and equipment .used during construction shall be serviced, fueled, and maintained upland, unless otherwise approved by Ecology, in order to prevent contamination to any surface water. . D6. Wash water containing oils, grease, or other hazardous materials resulting from wash down of equipment or working areas shall be contained for proper disposal, and shall not be discharged into state waters or sto1m drains. D7. Clean Fill Critel'ia: Applicant shall ensure that fill (soil) placed for the proposed project does not contain toxic materials in toxic amounts. D8. Work in or near the water that may affect fish migration, spawning, or rearing shall cease immediately upon a determination by Ecology that fisheries resources may be adversely affected. D9. All manmade debris that has been deposited below the Ordinary High Water Line within the constrnction work area shall be removed and disposed of upland such that it does not enter waters of the state. Concrete rubble, metal debris, and other debris in the construction work corridor that have washed into wetland and freshwater areas shall be removed from the project area. D10. _In-water work shall be limited to activities required to bypass the creek, including fish exclusion and installation of cofferdams. The remainder of project activities shall occur. once the stream has been bypassed. Dl 1. Sediment-laden water generated dming construction shall be pumped to an infiltration or filtration site, or to a settling at·ea, for subsequent treatment prior to returning water to streams .. D12. Discharge ofretum water back to streams shall occur in such a manner as to not cause erosion. Dl3. Impacts to native vegetation shall be minimized to the extent practicable. D 14. In-stream willow removal shall be limited to the minimum amount required to restore flow conditions. D15. Removal of any willow branches and roots shall be conducted by hand 01· handheld small machinery in order to minimize disturbance. D16. In-water work shall be conducted during low-flow stream conditions. Order #9352, -vrps Reference# NWS-2010-158 King County Water and Land Resources Division Janua,J' 8, 2013 Page9 o/19 D 17. Construction equipment shall use existing farm access roads to cross the wetland and access the stream, to the extent practicable. Dl8. Equipment staging areas shall be located outside of stream and wetland buffers. D 19. Stream bed gravel stockpiles shall be located outside of stream and wetland buffers. D20. Low~impact tracked or rubber-tired construction equipment shall be used to minimize disturbance to the wetland. D2 l. Machinery for removing sediment and reed canarygrass shall be operated from the bank. D22. Trucks utilized for transpo1tation of sediments to temporary drying areas shall incorporate appropriate BMPs in order to prevent spillage of sediment-laden water into waters of the state. D23. Dredging shall be limited to deepening of the streambed. Banks shall not be disturbed. D24. Any excess material from construction shall be disposed of at an approved off-site disposal location. D25. Sediment disposal areas shall be stabilized using upland area erosion control seed mix. Prior to seed germination, a silt fence shall be installed and maintained around the sediment disposal areas. E. Sediment Monitoring Conditions: El. The Applicant shall implement downstream post-constmction erosion monitoring per the Memorandum from Bill Kerschke and Julia Turney, King County, to Dori Althauser, · King County, RE: May Creek Drainage Improvement Project (9Al20S) Post-Construction Erosion Monitoring Plan-Downstream of 148111 Avenue SE, dated August 4, 2011, including the May Creek Canyon Reach Draft Monitoring Plan: May Creek Sediment Transport Study Phase 4, prepared by Anch01· QEA, LLC, dated · December 2010, (jointly hereafter called the "Downstream Erosion Monitoring Plan), and any conditions of this Order. · E2. Any modifications or changes to the Downstream Erosion Monitoring Plan shall be submitted to Ecology for review and approval per Condition A2 within 30 days of submitting the annual report. r OJ'der #9352, Lvtps Refe/'e11ce # NWS-2010-158 King County Water and Land Resources Dll'is/011 Jan11a1)' 8, 2013 Page .10 o/19 E3. Monitoring shall occur for a minimum of five (5) years post-constrnction. Depending on the results of downstream post-constrnction erosion monitoring, additional monitoring may be required. E4. Downstream post-construction erosion monitoring rep01ts for Years 1-5 shall be submitted to Ecology per Condition A2 by February 1 of each year. ES. After eac_h critical flood event, including the 1.0, 1.25, and 2-yeai· flood events, the Applicant shall monitor downstream locations per the Downstream Erosion Monitoring Plan for the presence or absence of bed hooks (eye bolts) or exposure of the bank pins (rebar). E6. The Applicant shall develop and utilize a downstream erosion monitoring form and provide training in the monitoring methods and use of the monitoring form to any monitors, including non-County staff, in order to ensure consistent data collection. The form shall include the date and time of observation and shall be utilized for 1.0, 1.25, and 2-year flood events. E7. If ernsion is detected through the downstream monitoring, the Applicant shall revise _the Downstream Erosion Monitoring Plan to include the following: a. Actions to be taken to address erosion impacts, including impacts on fish habitat. Erosion impacts will be considered to be impacts on fish habitat. b. Contingencies for any additional erosion. F. Emergency/Contingency Measures: F 1. The Applicant shall develop and implement a Spill Prevention and Containment Plan for all aspects of this project. F2. The Applicant shall have adequate and appropriate spill response materials on hand to respond to emergency release of petroleum products or any other material into waters of the state. F3. Fuel hoses, oil drums, oil or fuel transfer valves and fittings, etc., shall be checked regulal'iy for drips or leaks, and shall be maintained and stored properly to prevent spills into state waters. F4. Any work that is out of compliance with the provisions of this Order, or conditions causing distressed or dying fish, 01· any discharge of oil, fuel, or chemicals into state waters, or onto land with a potential for entry into state waters, is prohibited. If these occur, the Applicant shall immediately take the following actions: Order 119352, .... orps Reference# NIYS-2010-158 King County Water and Land Resources Division Janua,J' 8, 20 I 3 Page I I o/19 a .. Cease opet'!ltions at the location of the violation or spill. b. Assess the cause of the water quality problem and take appropriate measures to correct the problem and/or prevent fmther environmental damage. c. Notify Ecology of the failure to comply. All oil spills shall be reported immediately to Ecology's 24-Hour Spill Response Team at 1-800-258-5990, and within 24 hours of spills or other events to Ecology's 401/CZM Federal Project Manager at ( 425) 649- 7129 or (425) 649-7000. d. Submit a detailed written report to Ecology within five (5) days that describes the nature of the event, conective action taken and/or planned, steps to be taken to prevent a recmTence, results of any samples taken, and any other pertinent information. Compliance with this condition does not relieve the Applicant from responsibility to maintain continuous compliance with the terms and conditions of this Order or the · resulting liability from failure to comply. G. Timing Requirements G 1. All in-water work shall be completed by the work window identified· in the most c1UTent Hydraulic Project Approval (HP A) issued for this project. Any project change that requires a new or revised HP A should also be sent to Ecology for review. G2. This Order is valid until all compliance requirements in this document have been met. H. Repo1·ti11g and N otiflcatlon Requirement Conditions Hl. The Applicant shall provide to Ecology;s 401/CZM Federnl Permit Manager a copy of the final Corps permit within 2 weeks of receipt ofthe permit. A copy shall be submitted per condition A2 above. H2. Applicant shall provide notice to Ecology's 401/CZM Federal Project Manager: o At least three (3) days prior to the start of each construction season. o Within 14 days after completion of construction for each season at the project site. Notification, referencing Corps Reference #NWS-2010-158, Order #9352 can take place by telephone to (425) 649-7129 or (425) 649-7000, fax to (425) 649-7098, or in writing. • Order #93S2, .ps Reference # NWS-2010-1 SB King County Water and Land Resources Dil'islon Ja,mary 8, 2013 Page 12 o/19 H3. If the project construction is not completed within 13 months of issuance of this Ordel', the Applicant shall submit per Condition A2 a written construction status report and submit status rep01ts every 12 months until construction and planting is complete. You have a right to appeal this Order to the Pollution Control Hearing Board (PCHB) within 30 days of the date of receipt of this Order. The appeal process is governed by Chaple!' 43.218 RCW and Chapter 371-08 WAC. "Date of receipt" is defined in RCW 43.218.001(2). To appeal you must do both of the following within 30 days of the date ofreceipt of this Order: File your appeal and a copy of this Order with the PCHB (see addresses below). Filing means actual receipt by the PCHB dUl'ing regular business hours. Serve a copy of your appeal and this Order on Ecology in paper form -by mail or in person. (See addresses below.) E-mail is not accepted. You must also comply with other applicable requirements in Chaptel' 43.21B RCW and Chapter 371-08 WAC. Department of Ecology Attn: Appeals Processing Desk 300 Desmond Drive SE Lacey, WA 98503 Pollution Control Hearings Board 1111 Israel Road SW STE301 Tumwater, WA 98501. Please direct all·questions about this Order to: Rebekah Padgett Department of Ecology Northwest Regional Office 3190 1601h Avenue SE Bellevue, WA 98008 (425) 649-7129 rebekah.padgett@ecy.wa.gov Department of Ecology Attn: Appeals Processing Desk PO Box47608 Olympia, WA 98504-7608 Pollution Control Hearings Board PO Box 40903 Olympia, WA 98504-0903 Pollution Control Heal'ings Board Website www.eho.wa.gov/Boards PCHB.aspx Order #9352, ~o,ps Reference #NWS-20/0-158 King County Water and land Resow·ces Division January 8, 2013 Page 13 o/19 Chapte1· 43.218 RCW -Environmental and Land Use Hearings Office -Pollution Control Hearings Board http://apps.leg.wa.gov/RCW /default.aspx?cite=43 .21 B Chapter 371-08 WAC -Practice And Procedure http://apps. leg. w~ .gov/WAC/defau lt.aspx?ci te=3 71-08 Chapter 90.48 RCW -Water Pollution Control http://apps.leg.wa.gov/RCW /default.aspx?cite=90.48 Chapter 173-204 WAC -Sediment Management Standards www.ecy.wa.gov/biblio/wacl 73204.html Chapter 173-200 WAC -Water Quality Standards for Gt·oun<I Waters of the State of Washington www.ecy.wa.gov/biblio/Wac 173200.html Chapter 173-201A WAC -Water Quality Standards for Surface Waters of the State of Washington www.ecy.wa.gov/bib\io/wac 17320 I A.html Erik Stockdale, Unit Supervisor Wetlands/401 Unit Shorelands and Environmental Assistance Program Northwest Regional Office 1-'6-Wt~ January 8, 2013 Order #9352 •• ps Refere11ce # NWS-2010-158 King Cou11/y Waler and Land Reso11rces Division Jamiary 8, 2013 Page 14 o/19 ATTACHMENT A KING COUNTY WATER AND LAND RESOURCES DIVISION MAY CREEK DRAINAGE IMPROVEMENT PROJECT Water Quality Ce1·tlflcatlon Order #9352 Statement of Understanding of Water Quality Certification Conditions I have read and understand the conditions of Order #9352 Section 401 Water Quality Certification for the King County Water and Land Resources Division May Creek Drainage Improvement Project. I have also read and understand all permits, plans, documents, and approvals associated with the project referenced in this Order. Signature Date Title Company 01'del' #9352, _J/'ps Reference# NWS-2010-158 King County Water and Land Resources Division Janua,y 8, 2013 Page 15 o/19 Attachment B Information for As-built Reports (See Condition B15) KING COUNTY WATER AND LAND RESOURCES DIVISION MAY CREEK DRAINAGE IMPROVEMENT PROJECT Water Qualily Certification 01·der 1#9352 Backgronnd I11fo1·matio11 I) Project name. Corps Reference l#NWS-2010-158 2) Ecology docket number and the Corps reference number. 3) Name and contact information for the parties responsible for the mitigation site including: a) The applicant. b) The landowner. c) · Wetland professional on site during construction of the compensatory mitigation site. 4) Name and contact information for the party responsible for preparing the repo1t. 5) Who the repmt was prepared for (name, address, and phone number) { If different .from number 3 above.} 6) Month and year the report was produced. The Development Site 7) Brief description of the development project. Include: a) Directions to the site. · b) Month and year construction of the development project struted and ended. c) Area (acres) and type(s) (rating category, HOM classification, and Cowardin classification) of wetlands that were actually impacted by the development project, including temporary impacts. The Compensatory Mitigation Project 8) Brief description of the final compensatory mitigation project with any chru1ges from the approved plan made during construction. Include: a) Directions to the site. b) Who completed the compensatory mitigation project (name, address, and phone number. c) Acreage and type(s) (re-establishment, rehabilitation, creation, enh811cement, and preservation) of mitigation authorized to compensate for wetland impacts. d) Important dates including: i. Month and year the wetland impacts occmred. ii. When work on the compensatory mitigation site began and ended. •• Order #9352rrps Refere11ce # NWS-2010-158 Ki11g Co1111ty Wale,· and La11d Resources Division Ja11uary• 8, 2013 Page 16 o/19 iii. When different activities began and ended such as grading, removal of invasive plants, installing plants, and installing habitat features. 9) Description of any problems encountered and solutions implemented (with reasons for changes) during construction of the compensatory mitigation site. I 0) Any changes to the goals, objectives, and petformance standards of the compensatory mitigation project. 11) List of any follow-up actions needed, with a schedule. 12) Final site maps (8 1/2" x 11" or larger) of the compensatory mitigation site(s) including the following (at a minimum). a) Geographic location of the site with landmarks; b) Cleat· delineation of the project perimeter(s); c) Topography (with a description of how elevations were determined),; d) Installed planting scheme ( quantities, densities, sizes, and approximate locations of plants, as well as the source(s) of plant material); e) Location of habitat features; l) Location of permanent photo stations. The final site maps should reflect on-the-ground conditions after the site work is completed. Include the month and year when the maps were produced and, if applicable, when information was collected. · 13) Photographs of the site at as-built conditions taken from permanent photo stations. We recommend photo pans. 14) Copies of any records of deed notification or conservation easements. Order #935,. rps Reference# NWS-2010-i 58 Kf11g County Water and Land Resources Division January 8, 20/ 3 Page 17 o/19 Attachment C Wetlan,d Notice for Deed Notification (See Condition B16) KING COUNTY WATER AND LAND RESOURCES DIVISION MAY CREEK DRAINAGE IMPROVEMENT PROJECT Water Quality Certification Order #9352 Corps Reference #NWS-2010-158 Tax Parcel Number: --------------------------- Leg a I Description: __________________________ _ Legal Owner: ___________________________ _ NOTICE: This property contains wetlands as defined by Chapter 36.70A030(20) RCW, Chapter 90.58.030 (2)(h) RCW and WAC 173-20 I A-020. The property was the subject of an Ecology action under Chapter 90.48.260 RCW 01· Chapter 90.48.120(1) RCW. --------------------~issuedon ______ ~20_ (Corps federal refel'ence #) Ecology Docket# ~ h --------------------------------(Applicant Name) (Project Name) Restrictions on use or alteration of the wetlands may exist due~ natural conditions of the property and resulting regulations. A copy ofEcology's Order and the site map from the final wetland mitigation plan indicating the location of wetlands and their buffers is attached he!'eto. EXECUTED this ____ day of ______ __, 20 __ State of Washington) County of __ __, 1 certify that I know.or have satisfactory evidence that __________ _ Signed this instrument and acknowledged it to be his/her free and voluntary act for the uses and purposes mentioned in this instrument. GIVEN under my hand an official seal this ___ day of _____ ~20 __ NOTARY PUBLIC in and for the state of Washington, residing at .(Amended by Ord. 11200 § 50 (part), 1996) • Order #93.52.ps Reference# NWS-2010-1.58 King County Water and land Resources Division January 8, 2013 Page 18 o/19 Attachment D Required ][nformation for Monitoring Reports (See Condition B:D.9) · KING COUNTY WATER AND LAND RESOURCES DIVISION MAY CREEK DRAINAGE IMPROVEMENT PROJECT Water Quality Certification Order #9352 Corps Reference #NWS-2010-158 Ecology requires the following information, for monitoring reports submitted under this Order. Ecology will accept additional information that may be required by other regulators. Backgrnund Information 1) Project name · 2) Ecology docket number and Corps refere1ice number 3) Name and contact infonnation of the paities responsible for the mitigation site including:· a) The applicant b) The landowner 4) Name and contact infonnation for the party responsible for the monitoring activities and report 5) Who the repo1t was prepared for (naine, address, and phone number) { if different ji'0/11 number 3 above.} 6) Month and year the monitoring data were collected 7) Month and year the report was produced Mitigation Project Information 8) Brief description of the mitigation project including: a) Directions to the site b) Acreage and type(s) (re-establishment, rehabilitation, creation, enhancement, and preservation) of mitigation authorized to compensate for wetland impacts 9) Brief description of monitoring approach and methods. 10) A list of the goals and objectives for the mitigation project 11) Smlllllary table of monitoring data compared with performance standards. Using the monitodng data, describe how the site is developing toward goals and objectives and whether the project is in compliance with performance standards 12) Summruy (including dates) of management actions (maintenance, contingencies, and con-ective actions) implemented·at the site(s) 13) Summary of any difficulties or significant events that occurred on the site that may affect the ultimate success of the project Order #935~ 1ps Refere11ce # NIVS-2010-158 King Co1111ty Waler t/11d Land Resources Divls/011 January 8, 20 /3 Page 19 o/19 14) Specific recommendations for any_ additional corrective actions or adaptive management with a time table 15) Summary of any lessons learned 16) Site maps (8 1/2" x 11" or larger) of the compensat01y mitigation site(s) including the following (at a minimum): a) The month and year when the maps were produced and, if applicable, when information was collected b) The geographic location of the site with landmarks. c) Clear delineation of the project perimeter(s). d) Species, numbers, and approximate locations of all replanted material vegetation. e) Location of habitat features. I) Location of permanent photo stations and location of any other pliotos. g) Location of sampling points or transects. 17) Photographs taken at permanent photo stations (and other photographs as needed) from the _ most recent monitoring visit, which are dated and clearly indicate the direction from which the photo was taken. We recommend photo pans. STATE OF WASHINGTON DEPARTMENT OF ECOLOGY Northwest Regional Office• 3190 160th Ave SE• Bellevue, WA 98008·5452 • 425-649-7000 711 for Washington Relay Service • Persons with a speech disability can call 877-833-6J41 January 8, 2013 Doug Chin, Ptoject Manager King County Water and Land Resources Division 201 South Jackson Street, Suite 600 Seattle, WA 98104-3855 Dear Mr. Chin: RE: Coastal Zone Consistency for Corps Reference #NWS-2010-158 U.S. Army Corps Public Notice for Individual Section 404 Permit, May Creek Drainage Improvement Project, in Renton, King County, Washington On June 20, 2012, King County Water and Land Resources Division submitted a Certification of Consistency with the Washington State Coastal Zone Management Program (CZMP). Pursuant to Section 307(c)(3) of the Coastal Zone Management Act of 1972 as amended, Ecology concurs with King County WLRD's determination that the proposed work is consistent with Washington's CZMP. If you have any questions regarding Ecology's consistency determination please contact Rebekah Padgett at (425) 649-7129. You have a right to appeal this Order to the Pollution Control Hearing Board (PCHB) within 30 days of the date of receipt of this Order. The appeal process is governed by Chapter 43.21B RCW and Chapter 371-08 WAC. "Date of receipt" is defined in RCW 43.21B.001(2). To appeal you must do all of the following within 30 days of the date of receipt of this Order: • File your appeal and a copy of this Order with the PCHB (see addresses below). Filing means actual receipt by the PCHB during regular business hours. e Serve a copy of your appeal and this Order on Ecology in paper form -by mail or in person. (See addresses below.) E-mail is not accepted. You must also comply with other applicable requirements in Chapter 43.21B RCW and Chapter 371-08 WAC. Doug Chin Page 2 of2 January 8, 2013 • Department of Ecology Department of Ecology Attn: Appeals Processing Desk · 300 Desmond Drive SE Lacey, WA 98503 Pollution Control Hearings Board 1111 Israel RD SW STE 301 Tumwater, WA 98501 Sincerely, -:f:iit--~L-~ Erik Stockdale, Unit Supervisor Northwest Regional Office Attn: Appeals Processing Desk PO Box 47608 Olympia, WA 98504-7608 Pollution Control Hearings Board PO Box 40903 . Olympia, WA 98504-0903 Shorelands.and Environmental Assistance Program ES:rrp:cja By certified mail: 7012 1640 0000 6245 9580 cc: Lori Lull, U.S. /\rmY Corps of Engineers Larry Fisher, Washington Department of Fish and Wildlife · Karen Walter, Muckleshoot Indian Tribe Katie Bonwell e-cc: . Patrick McGraner -NWRO Patricia Olson -HQ Loree' Randall -HQ Raman Iyer -NWRO ecyrefedpermits@ecy.wa.gov. Jennifer Henning, City of Renton Jhenning@Rentonwa.gov Karen Walter, Muckleshoot Indian TribeKWalter@muckeshoot.nsn.us Jean Rollins urbanseparator@hotmail.com Debra Rogers herogers@comcast.net Susan Malin susiemalin@msn.com Gary Amundson_ gary.a@comcast.net . Andrew Duffus klassicars@hotmail.com Carol Tabacek caroltabacek@aol.com Mary Weirich maryyweirich@comcast.net A. Duffus blueheron6987@hotmail.com Julie Bonwell jbonwell@lesourd.com Mary Celigoy maryceligoy@comcast.net STATE OF WASHINGTON DEPARTMENT OF ECOLOGY PO Box 47600 • Olympia, WA 98504-7600 • 360-407-6000 711 for Washington Relay Service• Persons with a speech disability can call 877-833-6341 May 26, 2011 Doug Chin King County Water and Land Resources Division 20 I South Jackson Street, Suite 600 Seattle, WA 98104-3855 RE: Coverage under the Construction Stormwater General Permit Permit number: Site Name: Location: Disturbed Acres: Dear Mr. Chin: WAR-124978 May Creek Drainage Improvement Project (9A1205) SE May Valley Road Renton, WA King County 4.7 The Washington State Department of Ecology (Ecology) received your Notice of Intent for coverage under Ecology's Construction Stormwater General Permit (permit). This is your permit coverage Jetter. Your permit coverage is effective on May 26, 2011. Please retain this permit coverage letter with your permit ( enclosed), stormwater pollution prevention plan (SWPPP), and site log book. These materials are the official reeord of permit coverage for your site. Please take time to read the entire permit and contact Ecc>fogy if you have any questions. · Appeal Process You have a right to appeal coverage under the general permit to the Pollution Control Hearing Board (PCHB) within 30 days of the date of receipt of this letter. This appeal is limited to the general permit's applicability or non-applicability to a specific discharger. The appeal process is governed by chapter 43.21B RCW and chapter 371-08 WAC. "Date of receipt'' is defined in RCW 43.21B.001(2). Doug Chin May 26, 2011 Page2 • To appeal, you must do the following within 30 days of the date of receipt of this letter: o File your appeal and a copy of the permit cover page with the PCHB (see addresses below). Filing means actual receipt by the PCHB during regular business hours. o Serve a copy of your appeal and the permit cover page on Ecology in paper form - by mail or in person (see addresses below). E-mail is not accepted. You must also comply with other applicable requirements in chapter 43.21B RCW and chapter 371- 08 WAC. Address and Location Information: Street Addresses: Department of Ecology Attn: Appeals Processing Desk 300 Desmond Drive SE Lacey, WA 98503 Pollution Control Hearings Board (PCHB) 1111 Israel Road SW, Suite 30 I Tumwater, WA 98501 Mailing Addresses: Department of Ecology Attn: Appeals Processing Desk P0Box47608 Olympia, WA 98504-7608 Pollution Control Hearings Board P0Box40903 Olympia, WA 98504-0903 Electronic Discharge Monitoring Reports (WA WebDMR) This permit requires that Pcrmittees submit monthly discharge monitoring reports (DMRs) electronically using Ecology's secure online system, WA WebDMR. To sign up for WA WebDMR go to: www.ecy.wa.gov/programs/wq/permits/paris/webdmr.html. If you have questions, contact Tonya Wolfe at (360) 407-7097 (locally), or (800) 633-6193/ciption 3, or email WAWebDMR@ecy.wa.gov. Ecology Field Inspector Assistance If you have questions regarding storm water management at your construction site, please contact, Ken Waldo at ( 425) 649-7279, or ken.waldo@ecy.wa.gov; or, for Linear Transportation projects - WSDOTand local governments, Cynthia Walckerat (425) 649-7276, or cynthia.walcker@ecy.wa.gov; both of Ecology's Northwest Regional Office in Bellevue. Questions or Additional Information Ecology is committed to providing assistance. Please review our web page at: www.ecy.wa.gov/programs/wq/stormwater/eonstruction/. lfyou have questions about the construction stormwater general permit, please contact Clay Keown at (360) 407-6048, or clay.keown@ecy.wa.gov. Sincerely, Bill Moore, .E. Program Development Services, Section Manager Water Quality Program Enclosure • ' Washington Department of FISH and WILDLIFE HYor. ULIC PROJECT APPROVAL RCW 77.55.021 • See appeal process at end of HPA North Puget Sound 16018 Mill Creek Boulevard Mill Creak, WA 98012-1296 (425) 775-1311 Issue Date: September 26, 2011 Control Number: 123184-2 N/A Project Expiration Date: August 10, 2016 ' PERMITTEE King County Water and Land Resources Division ATTENTION: Doug Chin 201 S Jackson St Ste 600 Seattle, WA 98104 206-296-8315 Fax: 206-296-0192 FPNPublic Notice#: AUTHORIZED AGENT OR CONTRACTOR Project Name: May Creek Drainage Improvement Project (9A1205) Project Description: Improve in-stream flow conditions along segments of May Creek in May Valley between approximately River Mile 4.3 and 4.9. Remove vegetation and instream debris which is impeding flows and dredge 4,050 cubic yards of sediment from May Creek. Stream and wetland mitigation consists of: 1. Enhancing a 15 foot wide buffer of vegetation on each side of May Creek. 2. Installation of off-channel alcoves adjacent to May Creek downstream of 148th Ave. SE. 3. Restoration at the lower end of Long Marsh Creek. PROVISIONS 1. The project may begin immediately and shall be completed by August 10, 2016, provided work below the ordinary high water line (OHWL) shall occur only between June 16 and September 15. 2. NOTIFICATION REQUIREMENT: The Area Habitat Biologist (AHB) listed below (e-mail to fisheldf@dfw.wa.gov) and the Enforcement Program Officer (e-mail to capeljlc.@dfw.wa.gov) shall receive e-mail notification from the person to whom this HPA is issued (permittee) no less than three working days prior to start of work, and again within seven days of completion of work to arrange a compliance inspection. The notification shall include the permittee's name, project location, starting date of work or completion date of work, and the control number of this HPA. 3. Work shall be accomplished per plans and specifications approved by the Washington Department of Fish and Wildlife (WDFW) entitled, "MAY CREEK DRAINAGE IMPROVEMENT", dated September 15, 2011; "LONG MARSH CREEK RESTORATION", dated July 18, 2011; and "May Creek Drainage Improvement Project (901205) King County Water and Land Resources Division Stream and Wetland Impact Analysys and Mitigation Plan", dated revised September 2011, except as modified by this HPA. A copy of these plans shall be available on site during construction. 4. Installation of project mitigation components are required to compensate for impacts of the project on fish life and shall be overseen by a qualified stream ecologist. 5. A temporary bypass to divert flow around the work area shall be in place prior to initiation of nthF!r wnrk within thP. wP.ttP.rl nP.rimP.IP.r. · Washington Department of FISH and WILDLIFE HYDFr)JLIC PROJECT APPROVAL. North Puget Sound 16018 Mill Creek Boulevard Mill Creek. WA 98012-1296 (425) 775-1311 RCW 77.55.021 -See appeal process at end of HPA Issue Date: September 26, 2011 Control Number: Project Expiration Date: August 10, 2016 FPA/Public Notice#: 123184-2 N/A 6. A sandbag revetment or similar device shall be installed at the bypass inlet to divert the entire flow through the bypass. 7. A sandbag revetment or similar device shall be installed at the downstream end of the bypass to . prevent backwater from entering the work area. 8. The bypass shall be of sufficient size to pass all flows and debris for the duration of the project. 9. Prior to releasing the water flow to the project area, all instream work shall be completed. 10. Upon completion of the project, all material used in the temporary bypass shall be removed from the site and the site returned to preproject or improved conditions. 11. The permittee shall capture and safely move food fish, game fish, and other fish life from the job site. The permittee shall have fish capture and transportation equipment ready and on the job site. Captured fish shall be immediately and safely transferred to free-flowing water downstream of the project site. The permittee may request that WDFW assist in capturing and safely moving fish life from the job site to free-flowing water, and assistance may be granted if personnel are available. 12. Any device used for diverting water from a fish-bearing stream shall be equipped with a fish guard to prevent passage of fish into the diversion device pursuant to RCW 77.57.010 and 77.57.070. The pump intake shall be screened with 1/8-inch mesh to prevent fish from entering the· system. The screened intake shall consist of a facility with enough surface area to ensure that the velocity through the screen is less than 0.4 feet per second. Screen maintenance shall be adequate to prevent injury or eritrapment to juvenile fish and the screen shall remain in place whenever water is withdrawn from the stream through the pump intake. 13. Dredging shall be accomplished by starting at the upstream end of the project boundary and working downstream. 14. Dredging shall be limited to deepening of the streambed. Banks shall not be disturbed. 15. Upon completion of the dredging, the streambed shall be contoured with pools and riffles similar to its configuration prior to the dredging. 16. Salmonid spawning habitat at the confluence of Long Marsh Creek with May Creek shall not be impacted. There shall be a minimum of 18 inches deep spawning gravels there upon completion of dredging. 17. Materials placed at the outlet of the culvert on Long Marsh Creek shall consist of rounded boulders, cobbles, and gravel, rather than the riprap shown on page 4 of the plans for Long Marsh Creek. · Washington Department of FISH and WILDLIFE HYO'" -ULIC PROJECT APPROVAL RCW 77.55.021 -See appeal process at end of HPA Issue Date: September 26, 2011 Control Number: Project Expiration Date: August 10, 2016 FPA/Public Notice#: North Puget Sound 16018 Mill Creek Boulevard Mill Creek, WA 98012-1296 (425) 775-1311 123184-2 N/A 18. Fish habitat components as shown in the approved plans (Provision 3) are required as part of the project to mitigate project impacts. Large woody material installed as fish habitat components shall be coniferous and shall be installed in a manner sufficiently far from the bank to provide fully functioning fish habitat and shall be securely anchored to withstand 100-year peak flows using buried anchors and heavy duty chain or sufficient rock ballast. 19. Disturbance of the streambed and ba_nks and their associated vegetation shall be limited to that necessary to perform the project. Affected streambed and bank areas shall be restored to preproject or improved habitat configuration. Prior to December 31 of the year of project grading, the approved planting plan (Provision 3) shall be installed. Project performance standards, monitoring, maintenance, and contingencies shall occur as described in this plan on pages 27-28. 20. Equipment used for this project shall be free of external petroleum-based products while working around the stream and wetlands associated with the stream. Accumulation of soils or debris shall be removed from the drive mechanisms (wheels, tires, tracks, etc.) and undercarriage of equipment prior to its working below the OHWL. Equipment shall be checked daily for leaks and any necessary repairs shall be completed prior to commencing work activities along the stream and wetlands associated with the stream. 21. If at any time, as a result of project activities, fish are observed in distress, a fish kill occurs, or water quality problems develop (including equipment leaks or spills), immediate notification shall be made to the Washington Emergency Management Division at 1-800-258-5990, and to the AHB. 22. Erosion control methods shall be used to prevent silt-laden water from entering the stream and wetlands associated with the stream. These may include, but are not limited to, straw bales, filter fabric, temporary sediment ponds, check dams of pea gravel-filled burlap bags or other material, and/or immediate mulching of exposed areas. 23. Prior to starting work, the selected erosion control methods (Provision 22) shall be installed. Accumulated sediments shall be removed during the project and prior to removing the erosion control methods after completion of work. 24. Wastewater from project activities and water removed from within the work area shall be routed to an area landward of the OHWL to allow removal of fine sediment and other contaminants prior to being discharged to the stream or wetlands associated with the stream. 25. All waste material such as construction debris, silt, excess dirt.or overburden resulting from this project shall be deposited above the limits of floodwater in an approved upland disposal site. 26. If high flow conditions that may cause siltation are encountered during this project, work shall stop until the flow subsides. · Washington Department of FISH and WILDLIFE HYDFWJLIC PROJECT APPROVAL. RCW 77.55.021 -See appeal process at end of HPA · North Puget Sound 16018 Mill Creek Boulevard Mill Creek, WA 98012-1296 (425) 775-1311 Issue Date: September 26, 2011 Project Expiration Date: August 10, 2016 Control Number: FPA/Public Notice#: 123184-2 N/A 27. Extreme care shall be taken to ensure that no petroleum products, hydraulic fluid, fresh cement, sediments, sediment-laden water, chemicals, or any other toxic or deleterious materials are allowed to enter or leach into the stream or wetlands associated with the stream. NOTE This HPA is a modification of and supercedes the original HPA issued August 11, 2011 for this project. The modification pertains to updated plans referenced in Provision 3. PROJECT LOCATIONS Location #1 May Creek rm 4.3 to 4.9 WORK START: September 26, 2011 IWORKEND: August 10, 2016 WRIA: Waterbody: Tributary to: -- 08.0282 May Creek Lake Washington 114 SEC: Section: Township: Range: Latitude: --Longitude: County: NW 1/4 02 23N 05 E N 47.51149 W 122.13461 King Location #1 Driving Directions Location #2 May Creek rm 4.3 to 4.9 WORK START: September 26, 2011 IWORKEND: August10,2016 WRIA: Waterbody: Tributary to: -- 08.0282 May Creek Lake Washington 114 SEC: Section: Township: Range: Latitude: Longitude: County: ---- NE 1/4 03 23 N 05 E N 47.51599 W 122.14429 King Location #2 Driving Directions APPLY TO ALL HYDRAULIC PROJECT APPROVALS This Hydraulic Project Approval pertains only to those requirements of the Washington State Hydraulic Code, specifically Chapter 77.55 RCW (formerly RCW 77.20). Additional authorization from other public agencies may be necessary for this project. The person(s) to whom this Hydraulic Project Approval is issued is responsible for applying for and obtaining any additional authorization from other public agencies (local, state and/or federal) that may be necessary for this project. This Hydraulic Project Approval shall be available on the job site at all times and all its provisions followed by the person(s) to whom this Hydraulic Project Approval is issued and operator(s) performing the work. ~. Washington Department of FISH and WILDLIFE HYDr 'ULIC PROJECT APPROVAL· RCW 77.55.021 -See appeal process at end of HPA Issue Date: September 26, 2011 Control Number: Project Expiration Date: August 10, 2016 FPNPublic Notice#: This Hydraulic Project Approval does not authorize trespass. North Puget Sound 16018 Mill Creek Boulevard Mill Creek, WA 98012-1296 (425) 775-1311 123184-2 N/A The person(s) to whom this Hydraulic Project Approval is issued and operator(s) performing the work may be held liable for any loss or damage to fish life or fish habitat that results from failure to'comply with the provisions of this Hydraulic Project Approval. Failure to comply with the provisions of this Hydraulic Project Approval could result in a civil penalty of up to one hundred dollars per day and/or a gross misdemeanor charge, possibly punishable by fine and/or imprisonment. All Hydraulic Project Approvals issued under RCW 77.55.021 are subject to additional restrictions, conditions, or revocation if the Department of Fish and Wildlife determines. that changed conditions require such action. The person(s) to whom this Hydraulic Project Approval is issued has the right to appeal those decisions. Procedures for filing appeals are listed below. Requests for any change to an unexpired HPA must be made in writing. Requests for new HPAs must be made by submitting a new complete application. Send your requests to the department by: mail to the Washington Department of Fish and Wildlife, Habitat Program, 600 Capitol Way North, Olympia, Washington 98501-1091; e-mail to HPAapplications@dfw.wa.gov; fax to (360) 902-2946; or hand-delivery to the Natural Resources Building, 1111 Washington St SE, Habitat Program, Fifth floor. APPEALS INFORMATION If you wish to appeal the issuance, denial, conditioning, or modification of a Hydraulic Project Approval (HPA), Washington Department of Fish and Wildlife (WDFW) recommends that you first contact the department employee who issued or denied the HPA to discuss your concerns. Such a discussion may resolve your concerns without the need for further appeal action. If you proceed with an appeal, you may request an informal or formal appeal. WDFW encourages you to take advantage of the informal appeal process before initiating a formal appeal. The informal appeal process includes a review by department management of the HPA or denial and often resolves issues faster and with less legal complexity 'than the formal appeal process. If the informal appeal process does not resolve your concerns, you may advance your appeal to the formal process. You may contact the HPA Appeals Coordinator at (360) 902-2534 for more information. A. INFORMAL APPEALS: WAC 220-110-340 is the rule describing how to request an informal appeal of WDFW actions taken under Chapter 77 .55 RCW. Please refer to that rule for complete informal appeal procedures. The following information summarizes that rule. A person who is aggrieved by the issuance, denial, conditioning, or modification of an HPA may request an informal appeal of that action. You must send your request to WDFW by mail to the Washington Department of Fish and Wildlife HPA Appeals Coordinator, 600 Capitol Way North, Olympia, Washington 98501-1091; e-mail to HPAapplications@dfw.wa.gov; fax to (360) 902-2946; or hand-delivery to the Natural Resources Building, 1111 Washington St SE, Habitat Program, Fifth floor. WDFW must receive your request within 30 days from the date you receive notice of the decision. If you agree, and you applied for the HPA, resolution of the appeal may be facilitated through an informal conference with the WDFW employee responsible for the decision and a supervisor. If a resolution is not reached through the informal conference, or you are not the person who applied for the HPA, the HPA Appeals Coordinator or designee will conduct an informal hearing and recommend a decision to the Director or designee. If you are not satisfied with the results of the informal appeal, you may file a request for a formal appeal. B. FORMAL APPEALS: WAC 220-110-350 is the rule describing how to request a formal appeal of WDFW actions taken under Chapter 77.55 RCW. Please refer to that rule for complete formal appeal procedures. The following information summarizes that rule. Washington Department of FISH and WILDLIFE HYD~LIC PROJECT APPROVAL 0 North Puget Sound 16018 Mill Creek Boulevard Mill Creek, WA 98012-1296 (425)775-1311 RCW 77.55.021 -See appeal process at end of HPA Issue Date: September 26, 2011 Control Number: Project Expiration Date: August 10, 2016 FPNPublic Notice#: 123184-2 N/A A person who is aggrieved by the issuance, denial, conditioning, or modification of an HPA may request a formal appeal of that action. You must send your request for a formal appeal to the clerk of the Pollution Control Hearings Boards and serve a copy on WDFW within 30 days from the date you receive notice of the decision. You may serve WDFW by mail to the Washington Department of Fish and Wildlife HPA Appeals Coordinator, 600 Capitol Way North, Olympia, Washington 98501-1091; e-mail to HPAapplications@dfw.wa.gov; fax to (360) 902-2946; or hand-delivery to the Natural Resources Building, 1111 Washington St SE, Habitat Program, Fifth floor. The time period for requesting a formal appeal is suspended during consideration of a timely informal appeal. If there has been an informal appeal, you may request a formal appeal within 30 days from the date you receive the Director's or designee's written decision in response to the informal appeal. C. FAILURE TO APPEAL WITHIN THE REQUIRED TIME PERIODS: If there is no timely request for an appeal, the WDFW action shall be final and unappealable. ENFORCEMENT: Sergeant Chandler (34) P1 E Habitat Biologist Larry Fisher CC: 425-313-5683 ~'7_.· ..... c,-/-for Director WDFW ....... r • ,-·.: ~ King County '. Department of Penmttfng and Environmental Review 35030 se Douglas St., Ste. 210 Snoqualmie, WA 98065-9266 206•296·6600 TTY Relay 711 Clearing and Grading Permit type, Subtype: Grade, Grading Title: MAY CREEK DRAINAGE IMPROVEMENT Description: Removal of sediment on May Creek for In stream flow Improvements Location: Near SE May Valley Rd & 148th Ave. SE Permit Number: L 10CG223 Date Issued: 11/14/2012 Expiration Date: 11/14/2013 Permit Status: Permit Issued List of Parcels: 0223059005. 0223059075, 0223059076, 0223059084. 0223059091 Site Address: Valuation: $0.00 Applicant Name: KING COUNTY WLRD •- Applicant Address: ATTN DOUG CHIN 201 S JACKSON ST SUITE 600 MS: KSC-NR-0600 SEATTLE, WA98104 Owner Name: Owner Address: Please refer to ·the above projed number when making inquiries regarding this application. For Permit Information or requests for Inspections, call your Grading/Clearing Inspector at 1-888-546-7728. CERTIFICATION certify under penalty of pa~ury under the laws of the Stele of Washington that the information furnished by the owner or .owne~s agent In support of this application is true and correct I further certify that all applicable King County requirements for the work authorized by this permit, If issued, will be met and that violation thereof will be cause for code enforcement action. I have read the attached conditions of approval and understand that failure to comply with all conditions set forth herein shall necessitate an Immediate work stoppage until such time as compliance with the stipulated conditions is attained . Failure to comply or repeated violations of permit conditions may result on enforcement actions, civil penalties as authorized under K.C.C. Title 23, and/or permit suspension or revocation. The granting of this permit shall not be construed as satisfying the requirements of other applicable Federal, State or Local government permits or regulations . The operation and maintenance of facllltlas authorized under this permit shall ba conduded in accordance "with the Owner /Applicant Signature Title Date eaf-all-0028 printed: 11114/2012 Page 1 of 2 • ~ KlngCounty Permit: L 1 OCG223 Department of Permitting and Environmental Review 35030 SE Oouolas St., Ste. 210 Snoqu1lmle, WA 98065-9266 206·29&6600 m Relav. 111 lnispectoon Report Card Record Card must be on the Job site EROSION CONTROL DEVICES SHALL BE IN PLACE PRIOR TO AND DURING CONSTRUCTION APPROVALS: 1. Preconslruction Conference 2. Erosion Control (installed and functioning) 3. Limits of Clearing per Approved Plans 4. Construction Entrance installed per Plans 5. Site Stabilization and Soil Amendments Installed 6. Final-Site Re-vegelated and all Facilities Functioning p 7. Other B. Other Notes ALL PERMITS: By: -------By: ------- By: -------By: -------By: -------By: -------By: -------By: ------- a) Responsibility for the building's compliance with the provisions of the applicable King County Codes and for maintenance of the building rests exclusively with the permit applicants and their agents and the property owners. b) King County inspection of the building and real property are spot checks designed to foster and encourage compliance with the applicable codes. Neither the approvals above not the issuance of a Certificant of Occupancy guarantees or assures compliance with all applicable codes. ·. • . aaf"8U-002B printed: 11/14/2012 Page2of2 Conditions of Approval Grading Permit No. LI OCG223 May Creek Drainage Improvements 50 IO -At least 48 hours prior to the start of any work, call the Site Development Services Section at 206-296-6781 to arrange a preconstruction meeting. Be advised this permit shall not be effective until the notice to proceed has been issued pursuant to this meeting. 5011 -No construction under this permit shall take place until all other federal, state, and local permits have been obtained and are current with operating conditions and dates. Prior to commencement of construction under this permit the permittee shall provide copies of these issued project permits/approvals to DOES. 5015 -The boundaries of the clearing limits shown on this plan shall be clearly flagged in the field prior to construction. No clearing or other site work shall take place until these limits are approved in the field by DOES staff. During the construction period, no disturbance beyond the flagged clearing limits shall be permitted. The flagging shall be maintained by the permitted for the duration of the project. 5035 -Work shall be limited to that shown on the approved site plans dated 09/20/2012. A copy of the approved plans, conditions, and permit must be on the job site whenever work is in progress. 5045 -All land clearing debris to be removed·from the site shall be disposed of or recycled in an approved, legal disposal or recycling site. It shall .be the permittee's responsibility to locate acceptable disposal or recycling sites and to assure that all land clearing debris is disposed in those sites. 5046 -All surplus excavated sand, gravel, and other earthen materials to be removed from this site shall be disposed of in a legal manner, and to a legal permitted receiving site. It shall . be the permittee's responsibility under this permit to track and account for offsite disposal activities of earthen materials associated with this permit. 5048 -The permittee shall comply with local fire district rules and regulations regarding debris burning, fire prevention, and fire suppression. 5050 -All work shall comply with the provisions of King County ·ordinance 3139, relating to noise control. 5055 -A Hydraulic Project Approval (HPA) is required for this project. Contact the Washington State Department of Fish and Wildlife at 425-775-1311 for more information. • Conditions of Approval Grading Permit No. LI OCG223 Page2 • 5060 -Hours of operation shall be limited to 7:00am to 7:00pm, Monday through Saturday, and 10:00am to 5:00pm on Sundays. Hours ofoperation may be further restricted during peak traffic hours. 5070 -Permittee shall abide by the regulations of the Puget Sound Clean Air Agency (PSCAA). 5085 -You must call 1-800-424-5555 not less than 48 hours before beginning any site work where underground utilities may be located. Failure to do so could result in bearing substantial repair costs (up to three times the cost of repairs to the service). 5390 -The erosion and sedimentation control measures required for this permit are intended to be minimum requirements to meet anticipated site conditions. As work progresses and unexpected or seasonal conditions dictate, the permitted should anticipate that more siltation and sedimentation control facilities will be necessary to ensure complete silta- tion control on the proposed site. During the course of construction, it shall be the obligation and responsibility of the permitted to address any new conditions that may be created by site activities and to provide additional erosion sedimentation control measures. 5460 -Permitted shall be responsible for implementing all appropriate measures needed (i.e. paving, sweepers, and/or other techniques) to keep streets and roads used as haul routes, clean and free from debris, dirt, and mud. 5470-Any damage to pavement edges, sidewalk, curb and gutter, etc., resulting from operations authorized by this permit shall be repaired immediately. 5500 -During the time period of October I, through April 30, all disturbed areas that are to be left unworked for more than 2 days shall be covered by one of the following cover mea~ures: straw mulch, erosion control blankets or netting, plastic covering, or sodding. This requirement shall also apply during the time period of May I, through September 30, for all disturbed areas left unworked for more than 7 days. Cover measures shall comply with standards outlined in appendix "D" of the King County Surface Water Design Manual. Where straw mulch is used for site covering, a minimum 2 inch thickness shall be applied. 5505 -Clearing and erosion control measures for this site shall comply with section D.5.2- Wet Season Requirements -of Appendix D, of the 2009 King County Surface Water Design Manual for any work performed during the wet season (October I, through April 30). Conditions of Approval Grading Permit No. LI OCG223 Page 3 5510 -All project disturbed areas where site disturbance has occurred exposing mineral soil, shall be permanently seeded per standards outlined in section D.4.2.4 of the King County Surface Water Design Manual. 5520 -Filter fabric fence (silt fence) shall be used around the perimeter of the site, where necessary, to insure that sediment laden water does not leave the site. Filter fabric fence shall be installed and maintained per detail D.4.E-appendix D of the King County Surface Water Design Manual. 5522 -Work authorized by this permit shall be limited to tax parcel numbers 022305-9076, -9091, -9075, -9084, -9005, & 803540TR-A only. 5650 -A National Pollutant Discharge Elimination System (NPDES) permit for surface water discharge may be required for this project. Contact the Washington State Dept. of Ecology at (360) 649-7000 for information. 5700 -All subsequent site inspections required by this permit shall be billed at the applicable hourly rate as authorized by King County Code. 5800 -Critical Areas Conditions: By this reference, the conditions contained in the memo dated September 13, 2012, as revised November 6, 2012 from Nick Gillen, Environmental Scientist Ill, are hereby adopted as additional conditions of approval for this permit. A copy of these conditions are attached to this permit. 5810-Flood Hazard Review Conditions: By this reference, the conditions contained in the memo dated September 6, 2012 from Don Gauthier, Engineer Iii, are hereby adopted as additional conditions of approval for this permit relating specifically to disposal of earthen Dredging' s outside of the 100 year floodplain, and storage/ staging of materials and equipment within the I 00 year floodplain from September 30, to May I. A copy of this memo is attached to this permit. 5820 -The project representative shall monitor all grading and excavation to confirm that the work meets both design specifications of the approved engineering plans and remains consistent with the conveyance capacity improvements specified by the hydrologist. Written correspondence verifying compliance to the approved plans and the hydrologist's recommendations shall be presented to the project representative in the form of record · drawings. Field measurements may be requested by the permit agency(s) to King County for confirmation of compliance following completion of excavation prior to advancing to other properties. Conditions of Approval Grading Pennit No. LIOCG223 Page4 • 5900 -No construction under this pennit shall take place until all other federal, state, and local pennits have been obtained and are current with operating conditions and dates. These pennits may include but not limited to: Hydraulic Project Approval (HPA), Section 401 Water Quality Certification, Section 404 Permit, Storm Water NPDES; Prior to construction under this pennit, the pennittee shall provide copies of these issued project pennits/approvals to ODES. Conditions of Approval Grading Permit No. L 1 OCG223 Critical Areas Conditions of Approval Page 5 September 13, 2012 Revised November 6, 2012 TO: Jon Pederson, Site Development Specialist FM: Nick Gillen, Environmental Scientist III RE: May Creek Drainage Improvement Project, LIOCG223, Critical Area Conditions of Approval Staff has reviewed the submitted material for the above referenced file. Staff concurs that the projects meets the criteria as listed under 21A.24.045 (D-61 ), Allowed Alterations (Flood Risk Reduction Gravel Removal). The following conditions shall apply to this permit. I. All work within the aquatic area and wetlands should be completed during summer low water periods typically from mid May to mid September. Any work done outside to this window may require special erosion control measures and/or a biologist on-site during working hours. 2. All areas of disturbance shall be replanted with native vegetation within 3 months of completing construction activities. 3. The Long Marsh Creek Restoration Project is an important part of the May Creek Drainage project for controlling sediment in May Creek. Upon completion the restoration project it shall be monitored along with the May Creek project to determine if the goals and objectives as stated in the report have been or are being met. 4. The May Creek Mitigation plan, within the City of Renton, shall be implemented within 3 months of project completion. This out of county mitigation is subject to permits from the City. No work within King County may start without first obtaining the City permits or permission. If City permits cannot be obtained then an alternative mitigation plan will need to be submitted, reviewed and approved prior to any work within King County. 5. Monitoring reports shall need to be submitted to DPER once a year for five years after mitigation implementation. - ATTACHMENT A King County Department of Development and Environmental Services 900 Oakesdale Avenue SW . Renton; WA 98055-1219 (206) 296-6600 / Project Name: May Creek Restoration Adjacent Parcel Number(s): 0223059091 DDES Project Number: LlOCG223 Section A (this section to be completed by King County personnel) The proposed development site lies at least partially within the King County regulatory floodplain based on review and determination from any of the following sources: )( FEMA Flood Insurance Rate Map (FIRM): Panel# 53033C0669F Panel date: May 16, 1995 D Special Study as required by section 4.4.2 of the King County Surface Water Design Manual D Other: (please note source) Based on a review of the potential impacts .;r this project, a "zero-rise analysis": )( Is required_ Completion of Section B of this form by a registered professional engineer is a condition of the issuance of this permit. D Is not required for the following reasons: D Improvement to an existing structure without increasing the foundation footprint of the structure. o Post and pier foundation system with no significant impedance to flow. CJ Coastal "A11 zone D Shallow flooding area (AO/AH zone) not adjacent to a riverine system. (explain) D Ineffective flc;,w area. ( explain) o Proposed project lies within a hydraulic shadow. (explain) o Other ( explain) NOTE: Section A of this worksheet relates only to zero-rise analysis. Compensatory storage analysis and documentation requirements apply regardless of whether or not a zero-rise analysis is required- Approved by: By Jeff Pray DDES Engineer Date:. 9/2/2011 Date: ______________ _ ·--1- Jeff Pray December 7, 2011 Page2 ,Q~ \._ .J I the May Creek channel is shown in Table l. The approximate volume of ma\erial to be removed from the Long Marsh Creek channel and confluence area with May Creek is ~hown in Table 2. Sheet C3 of the Long Marsh Creek Plans (Map No. 2006-42) contains two p~ofile views showing the volumetric decrease, by comparing the 'EXISTJNG GROUND' ground surface with the 'DESIGN GRADE' surface. · j i Table 1 Volume of material removed from May Creek floorplain Channel and Miti2ation rea Volume Removed (CY) 5156 Table 2 Volume of material removed from the Long Marsh Creek channel and confluence area Channel and Miti11.ation A.rea Volume Removed (CY) 674 l I I I . The volume of floodplain material removed will increase the flood storage volume in the floodplain. The spoils disposal areas are shown on the plan set and are outsi~e the l 00-year floodplain. Therefore, volumetric calculations at one-foot contours are not ed. DN:bgoo6 cc: Lindsey Miller, Environmental Engineer, Environmental Unit, Road ervices Division, Department of Transportation Jeff Burkey, Hydrologist, Science and Technical Support Section, W ter and Land Resources Division (WLRD, Department of Natural Resources an4 Parks (DNRP) Doug Chin, Project Manager, Capital Services Unit, WLRD, DNRP I I .... -~ ' ..... -- ~ King County Water and Land Resources Division Department of Natural Resources and Parks King Street Center 201 South Jackson Street, Suite 600 Seattle, WA 98104-3855 206-296-6519 Fax 206-296-0192 TTY Relay: 711 December 7, 2011 I ! I TO: Jeff Pray, Engineer III, Engineering Services Section, Land Use Services Division, Department of Development and Environmental Services I VIA: Don A~Pi., Managing Engineer, Capital Services Unit, Wat~ and Land Resources Division (WLRD), Department of Natural Resources an;ci Parks (DNRP) FM: Dale N~ Engineer II, Capital Services Unit, WLRD, DNRP I RE: Floodplain Code Compliance for May Creek Drainage Improvement I I The May Creek Channel Restoration project is proposed for completion in sdmmer 2012. Because this project is within the May Creek 100-year regulatory floodplaiaj the project must ' meet the King County "Zero-Rise" and Compensatory Requirements as set firth in King County Code Title 21A. I • ! Zero-Rise Analysis I A Hydraulic and Hydrologic Analyses of the May Creek Drainage lmprov~ent Project was . completed in December 2010. That report is the basis for the zero-rise ana1)1lis of this project. The September 12, 2011 Progress Copy of the May Creek Drainage Improv~ent engineering plans and the July 20, 2011 Progress Copy of the Long Marsh Creek Project Fllgineering plans by the King County Department of Natural Resources and Parks were revie~ed for compliance with the King County "Zero-Rise" and Compensatory Requirements as set fc~rth in King County Code Title 21A. · I ! Figure 26 on page 34 of the Hydraulic and Hydrologic Analyses of the May ~reek Drainage Improvement Project shows that the 100-year surface water profiles are lowilted throughout the project reach. The report also states that "flood events greater than the 20-yciar event decrease ~~~~oop~~-I Compensatory Storage I The proposed project will not place additional fill within the floodplain. Th~ spoils disposal areas are shown on the plan set and are outside the I 00-year floodplain. The[ channel improvements will be removing floodplain material within the channel. The 1net effect will be to """""' "°rage witlrin 11,, floodpfain. The appro~=" "''=' of maeri,I I "'-'°" from Jeff Pray December 7, 2011 Page2 the May Creek channel is shown in Table 1. The approximate volume of malerial to be removed . ' from the Long Marsh Creek channel and confluence area with May Creek is ~hown in Table 2. Sheet C3 of the Long Marsh Creek Plans (Map No. 2006-42) contains two pfofile views showing the volumetric decrease, by comparing the 'EXISTING GROUND' ground s,urface with the 'DESIGN GRADE' surface. I I Table 1 Volume of material removed from May Creek floorplain Channel and Miti!!ation Area Volume Removed (CY) 5156 Table 2 Volume of material removed from the Long Marsh Creek channel and confluence area I Channel and Miti!!ation ,rea Volume Removed (CY) 674 The volume of floodplain material removed will increase the flood storage v6lume in the floodplain. The spoils disposal areru; are shown on the plan set and are outs*e the 100-year floodplain. Therefore, volumetric calculations at one-foot contours are not jeded. DN:bgoo6 I cc: Lindsey Miller, Environmental Engineer, Environmental Unit, Road tervices Division, Department of Transportation. Jeff Burkey, Hydrologist, Science and Technical Support Section, W ter and Land Resources Division (WLRD, DepartmentofNatural Resources anl Parks (DNRP) Doug Chin, Project Manager, Capital Services Unit, WLRD, DNRP . . I ....... j A' ' RECEIVED MAR 1 5 2011 K.C. Roads Engineering Services NMFS Tracking Nwnber: 2011/00601 Erick Thompson Road Services Division Department of Transportation KSC-TR-0231 201 S. Jackson Street Seattle, Washington 98104-3856 UNITED STATES DIEPARTMIENT OF COMMIERCIE National Oceanic and Atmospheric Administration NATIONAL MARINE FISHERIES SERVICE Northwest Region 76.00 Sand Point Way N.E., Bldg. 1 Seattle, Washington 98115 March 10, 2011 Re: Endangered Species Act Section 7 Informal Consultation and Magnuson-Stevens Fishery Conservation and Management Act Essential Fish Habitat Consultation for King County for the May Creek Drainage Improvement Project (Sixth-field Hydrologic Unit Code 171100120400, Lake Washington-Sammamish River). Dear Mr. Thompson: This correspondence is in response to your request for informal consultation under the Endangered Species Act (ESA) of 1973, as amended, 16 U.S.C. 1531. The National Marine Fisheries Service (NMFS) has reviewed the Biological Assessment (BA) for the above referenced proposal, received on February 25, 2011. King County (County) requested concurrence with its determination that the proposed action "may affect, but is not likely to adversely affect" the threatened Puget Sound (PS) Chinook salmon (Oncorhynchus tshawytscha) (70 FR 37160), and the threatened PS Steelhead (0. mykiss) (72 FR 26722). This consultation with the County is conducted under section 7(a)(2) of the ESA, and its implementing regulations, 50 CFR Part 402. There is no critical habitat in the action area. The County is proposing to improve in-stream flow conditions between approximately river mile (RM) 4.3 and 4.9 of May Creek. Sediment accumulation and in-stream vegetation have been gradually decreasing channel flow capacity, causing a backwater effect and increasing flood duration on pastures. The project includes vegetation and sediment removal, along with stream and wetland mitigation. Invasive reed canary grass and sediment will be removed from the channel with machinery, most likely a trackhoe operated from the bank. The stream will be diverted around the work site, and erosion and sediment control best management practices will be implemented. In addition, willows that are obstructing flow would be removed by hand or with hand-held machinery. Approximately 4,050 cubic yards of material will be removed from the stream channel. -. ='·· ; . "' 3 Magnuson-Stevens Fishery Conservation and Management Act Federal agencies are required, under section 305(b )(2) of the MSA and its implementing regulations (50 CFR 600 Subpart K), to consult with NOAA Fisheries regarding actions that are authorized, funded, or undertaken by that agency that may adversely affect Essential Fish Habitat (EFH). The MSA section 3 defines EFH as "those waters and substrate necessary to fish for spawning, breeding, feeding, or growth to maturity". If an action would adversely affect EFH, NMFS is required to provide the Federal action agency with EFH conservation recommendations (MSA section 305(b)(4)(A)). This consultation is based, in part, on information provided by the Federal action agency and descriptions ofEFH for Pacific · salmon contained in Appendix A to Amendment 14 to the Pacific Coast Salmon Plan (August 1999) developed by the Pacific Fishery Management Council and approved by the Secretary of Commerce (September 27, 2000). The proposed action and action area are described in this letter and in the BA. The action area includes habitat that has been designated as EFH for various life stages of Chinook and coho ( 0. kisutch) salmon. · EFH Conservation Recommendations: Because the conservation measures that the County included as part of the proposed action to address ESA concerns are also adequate to avoid, minimize, or otherwise offset potential adverse impacts to the EFH of the species listed · above, conservation recommendations pursuant to MSA (section 305(b)(4)(A)) are not necessary. Since NMFS is not providing conservation recommendations at this time, no 30- day response from the County is required (MSA section 305(b)(4)(B)). This concludes consultation under the MSA. If the proposed action is modified in a manner that may adversely affect EFH, or if new information becomes available that affects the basis for NMFS' EFH conservation recommendations, the County will need to reinitiate EFH consultation with NMFS in accordance with implementing regulations for EFH at 50 CFR 600.920(k). The NMFS appreciates your efforts to comply with requirements under the ESA and MSA. If you have questions, please contact Jody Walters at the Washington State Habitat Office, (360) 534-9307, or email Jody.Walters@noaa.gov. cc: Lori Lull, COE Sincerely, c. .. -cQ.. :) L; William W telle, Jr. '\) Regional A ministrator King County Department of lransportatlon Road Services DIVlslon Engineering Services section King Street Center 201 South Jad<son Street Seattle, WA 981()4·3856 206-296•6520 TIY Relay 771 www.klngcounty.gov/roads December 7, 2012 Lori Lull CityofR Ptannt,ig Denton 1vtston FEB I 2 lll/3 US Army Corps of Engineers Seattle District Regulatory Branch PO Box 3755 Seattle, WA 98124 !Rl~cr:~u~~© Rebekah Padgett Washington State Department of Ecology Northwest Regional Office 3190-160th Avenue SE Bellevue, WA 98008-5452 RE: May Creek Drainage Improvement Project (Reference #NWS-2010.158) King County Response to Public Notice Comments Dear Ms. Lull and Ms. Padgett: On behalf of the King County Water and Land Resources Division (WLRD) I am providing you with the enclosed responses to comments received during the joint Public Notice comment period for the May Creek Drainage Improvement Projects (Reference #NWS-2010.158). For convenience, we are providing the responses in a table fonnat. Please let us know what the next steps in the permitting process will be for this project and an estimated timeline for issuance of the permits. If you have any questions you can contact me at lindsey.miller@kingcounty.gov or (206) 296-3762 or contact Doug Chin at doug.chin@kingcounty.gov or (206) 296-8315. Sincerely, . Lindsey Miller Environmental Engineer King County Road Services Division Enclosure cc: Doug Chin, Project Manager, King County Water and Land Resources Division Don Althauser. Managing Engineer, King County Water and Land Resources Division l I • l"3J' I t" 'l I' King County May Creek Drainage Improvement-Joint Public Notice NWS-2010-158 Review Comments and Response Public Notice Comment Recipient: Lori Lull, US Army Corps of Engineers Comment Date: Rebekah Padgett, Washington Department of EcoJo,:,v November 19, 2012 Comment Response Prepared by: Doug Chin, King County Water and Land Division Response Date Lindsey Miller, King County Road Services Division December 6, 2012 Comment Comment Person/ Agency Comment Response Number Document Commenting 1 I0/25/2012 Jean Rollins First, in order to compare pre-project condition versus post project King County has already collected at least two waters of baseline data. King County conducted Letter conditions, the monitoring sites must be established and baseline data baseline monitoring December 2010, February 7, I 0, and 11; April 26, May 2 and November 21, 2011. Page I gathered pre-proiect, for at least two (2) water years. Please see the attached May Creek Phase 4 Monitoring Report. King County attempted to continue this monitoring into 2012 but at the end of2011 requests to key property owners, including Rollins/Duffus, for access to continue collection of monitoring data have not been approved. Also, although, Rollins/Duffus had agreed to do monitoring themselves and send in data, nothing has yet been reported to King County. King County can only conclude that there has not been any erosion, otherwise property owners would have informed us of any problems. King County feels that the monitoring conducted in 20 IO and 2011 provides an accurate baseline picture of the on-going erosion in the May Creek channel. King County is very willing to continue monitoring efforts if property owners allow access. King County and Washington Department of Ecology staff met at the Rollins/Duffus and Coates properties on April 2, 2012 to view May Creek on these two adjacent properties. Both agencies took photos and measurements at this time. 2 I0/25/2012 Jean Rollins Has Gage 37b been reinstalled and reconciled? In 2009, King County established a new gage (37H) about half a mile upstream of Gage 37B, at the SE Letter 143rd PL (a.k.a. Ilwaco Ave) crossing to replace gage 37B. King County continues to record water Page I level at the old 37B site. Based on a comparison between the new and old gage King County believes the difference in storm flow is negligible between the two sites, and that the new gage 37H represents the flow through the ravine better than the 37B site. This gage collects flow data continuously. 3 I0/25/2012 Jean Rollins Have each of the seven monitoring sties been established? Yes, King County is conducting baseline monitoring. Please refer to the response to Comment# I and Letter also to the May Creek Phase 4 Monitoring Report and the attached memo from Bill Kerschke and Julia Page2 Turney dated August 4, 2011 for details on the monitoring effort. 4 I0/25/2012 Jean Rollins Have pressure transducers, cross-section surveys, and placement of bed Please refer to the response to Comment #3. Letter hooks and/or bank pins been installed at the seven sites? Page 2 5 I0/25/2012 Jean Rollins Which sites have bed hooks installed, conversely which sites have bank Please refer to the response to Comment #3. Letter pins installed and which sites have both bed hooks and bank pins Page2 installed? Are there any field changes or deviations from the Monitoring Plan? 6 10/25/2012 Jean Rollins Has each of the seven monitoring sites been monitored during the past Please refer to the response to Comment #3. Letter two water years, if so where is the data? Page2 Page I December 6, 2012 -• .. . ' \ King County May Creek Drainage Improvement -Joint Public Notice NWS-2010-158 Review Comments and Response Comment Comment Person/ Agency Comment Response Number Document Commenting 20 10/15/2012 Muckleshoot The project also needs to mitigate for the loss of the full channel King County looked into a number of options for in-stream mitigation downstream of SE 1481h Ave. Letter Indian Tribe spanning pool at the Long Marsh Creek confluence. Due to the relatively flat topography at this location, the creation of meandering side channels and side Page 5 pools did not prove to be a good option because they would rapidly fill with sediment creating a high risk of stranding during summer low flows .. The alcoves that are proposed proved to be the best way to enhance in-stream habitat with a minimal risk of stranding. In addition, at the request of Washington Department of Fish and Wildlife (HPA 123184-2 Provision #16) King County will be salvaging the existing gravels at the Long Marsh Creek confluence prior to sediment removal. After the sediment is removed in this location, King County will over-excavate and replace at least 18-inches of gravels. The pool at this location is referred to as a Lateral Scour Pool in the Baseline Stream Conditions report (December 2010); however, this pool also meets the definition of a Channel Confluence Pool. Since King County will be replacing the existing gravels after the sediment is removed, and the confluence of Long Marsh Creek and May Creek will remain in this location, it is expected that the existing pool at this location will also exist post-construction. 21 10/15/2012 Muckleshoot A more robust monitoring plan is needed to assess the project's effects on King County is currently proposing to monitor vegetation coverage and survival as stated in Section 6.1 Letter Indian Tribe sediment transport/filling, flooding, habitat creation and riparian planting of the Impact Analysis and Miti,Jfation Plan. King Co_unty _is also proposing pos~-constru~tion erosion Pages success to provide shade and instream habitat. The alcoves should be monitoring downstream of 148 Avenue SE as descnbed m the Post-Constructwn Erosion Momtonng monitored to determine the amount of available rearing habitat over a Plan (memo dated August 4, 2011 from Bill Kerschke and Julia Turney). variety of flow conditions. The project should be monitored for IO years to determined project success (or failure) prior to allowing any new dredi(in~ in Mav Creek. Page 6 December 6, 2012 King County May Creel-. ,rainage Improvement-Joint Publi... _ ,otice NWS-2010-158 Review Comments and Response Comment Comment Person/ Agency Comment Response Number Document Commenting prop_osal fits within the King County budget. Third, the proposal does not require permanent fill in the wetland, stream, or floodplain (except streambed gravels for mitigation). In addition, the mitigation associated with this proposal will protect the stream by resorting native riparian/wetland vegetation and installing fences along the stream, which will prevent livestock access. King County is committed to ·preserving the unique character of our rural communities, and safeguarding and enhancing its natural resources and environment. 11 10/25/2012 Andrew Duffus What is the economic value to the four lucky property owners who Please refer to the response to Comment #10. - Letter personally will benefit from this proposal? Pa2:e I 12 10/25/2012 Andrew Duffus Why is the W &LRD proposing to spend $1.5 million dollars of taxpayer Please refer to the response to Comment #I 0. Letter money to dredge a creek and a wetland for the marginal benefit of four Pa2:e 2 private horse pastures? 13 10/25/2012 Muckleshoot. As noted in previous comments, our Habitat Program staff has con_cerns King County Water and Land Resources Division (WLRD) is providing three acres of wetland Letter Indian Tribe about dredging May Creek because of potential adverse impacts to enhancements and two acres of riparian/wetland buffer planting as mitigation for project impacts, Page 1 salmon and their habitat. The affected reach is identified as salmon including off-channel alcoves to provide salmon rearing habitat. King County acknowledges that some spawning and rearing habitat (May Creek Baseline Stream Conditions of the proposed mitigation for in-stream habitat impacts is out-of-kind mitigation and does not replace Report). This project would dredge 2,086 linear feet of stream bed and the same functions as those being impacted (see the discussion in Section 5.2 of the Impact Analysis remove reed canarygrass and willows from 14,500 square feet from May and Mitigation Plan, September 2011 ), which is one reason that the proposed out-of-kind mitigation is Creek and its associated wetland. As noted in various project documents, being provided at higher ratios than would be required for in-kind mitigation; however, King County this is the first of potentially four projects that would dredge of up to 2.26 believes that in the long-term the mitigation will provide an overall improvement to this reach of May miles of May Creek, which is 75% of the valley length and 32% of May Creek. Creek's entire length. The combined impact of all these dredging projects would likely result in significant loss of existing salmon habitat, and No future dredging projects are proposed by King County in May Creek at this time. If any additional potentially other future adverse impacts upstream and downstream from projects are proposed in the future, then mitigation will again be provided for adverse project impacts. the dredged reaches as additional landowners seek to protect their properties from bank erosion. We have recommended that King County implement and exhaust all less impacting alternatives prior to dredging May Creek. We remain concerned that this project will adversely affect salmon and aquatic habitats without mitigation for these impacts. 14 10/25/2012 Muckleshoot The project will impede the natural processes of sedimentation and Existing habitat in May Creek is quantified in detail in Section 4.2 of the Baseline Stream Conditions Letter Indian Tribe floodwater storage along May Creek without a full assessment of report (December 2, 2010). Figure 4 in this report shows each habitat unit identified during the stream Page2 potential habitat impacts.in the project area and in upstream and survey, and Table 1 summarizes the habitat units. Adverse impacts to these habitat units are quantified downstream areas. In particular, the potential pre-and post-project in Section 4.1 of the Impact Analysis and Mitigation Plan (September 2011). rearing habitat available for juvenile salmon in May Creek has not been quantified. Additionally, please refer to the response to Comment #13. Page 3 December 6, 2012 King County May Creek Drainage Improvement-Joint Public Notice NWS-2010-158 Review Comments.and Response • • Comment Comment Person/ Agency Comment Response Number Document Commenting 15 10/25/2012 Muckleshoot Additional mitigation is required to fully mitigate for unavoidable · King County WLRD has already taken steps to implement a number of the measures that the MIT Letter Indian Tribe environmental impacts. The following measures should be implemented suggests. These steps include: Page2 as additional mitigation: 1. King County WRLD has been coordinating closely with the King Conservation District (KCD) 1. Promotion and adoption of agriculture best management to encourage the property owners along May Creek to continue the implementation of their farm plans. Property owners along this reach of May Creek are implementing their farm plans practices, farm conservation plans, and other measures as in phases, as their budgets allow. King County WLRD and KCD met onsite with Washington appropriate to improve pasture conditions and control Department of Ecology in November 2011 to discuss priorities for farm plan implementation, sediment sources. and KCD is continuing to work with the May Creek property owners, to ensure the continued implementation of the farm plans by focusing on the highest priority elements first. It is not 2. Increase stream/wetland buffer width to a minimum of 25 foot financially feasible for the property owners to implement all components of their farm plans buffer width per the County Livestock Ordinance and increase simultaneously, so implementation is on ongoing process. Property owners are working with riparian planting in the project areas: KCD to secure grants to implement major elements of farm management plans. ,\ 3. Commit to mitigate any unavoidable impacts to fish habitat in 2. As part of KCD's ongoing coordination with the property owners to implement their farm plan, downstream areas that result from the project. additional buffer planting (beyond the 15 feet that will be planted by King County WRLD for the May Creek Drainage Improvement Project) is being proposed by some property owners for select reaches of May Creek. We continue to encourage property owners to plant larger buffers, 4. All of the mitigation areas need to be permanently protected even though King County Code 21A.30.045.B.I generally seeks to achieve only a 25-foot in a conservation easement or other protective mechanism buffer of mature vegetation between the stream and.grazing areas. with King County providing monitoring and maintenance of the mitigation areas. 3. King County does not expect the project to result in any adverse indirect impacts to salmon habitat downstream of the project area and therefore is not proposing any mitigation for habitat impacts downstream. The project's Biological Evaluation Report (February 2011) discusses the potential for indirect habitat impacts downstream in Section 4.2. 4. King County has committed to permanently protecting the mitigation sites on private properties with permanent protection documents and is in the process of negotiating for this permanent . protection. King County will monitor and maintain the mitigation areas in compliance with the conditions set forth in the nermits. Page4 December 6, 2012 King County May Creel. .Jrainage Improvement-Joint Publk ,,otice NWS-2010-158 Review Comments and Response Comment Comment Person/ Agency Comment Response Number Document Commenting 16 10/25/2012 Muckleshoot Overall, we are concerned that this project represents only a "short ierm King County has incorporated multiple elements into the project design that are intended to increase Letter Indian Tribe fix" to address flood concerns in May Valley. There is a high likelihood the longevity of ihe project including: Page2 that additional dredging will be proposed in the future in May Creek or 0 Designing the Long Marsh Creek portion of the project to trap and store sediment before it its associated wetlands resulting in cumulative and ongoing impacts to reaches the m·ainstem of May Creek. Calculations performed for the Long Marsh Creek fish and fish habitat. Restoration Basis of Design Report found ihat sediment storage capacity in Long Marsh Creek after the project is approximately 74 years. . 0 Planting a buffer .of native vegetation on both·sides of May Creek to help trap any sediment in pasture runoff before it reaches the stream. The beneficial effects of this approach are evident in the reach already planted immediately upstream of the project area. 0 Removing and controlling reed canary grass to help minimize the amount of organic material accumulating in the May Creek channel. 0 Reducing overbank flooding for flows between 6 and 50 cfs to reduce the amount of sediment being picked up from the pasture areas by floodwaters . . 0 Working with the KCD to encourage property owners to continue implementation of their farm management plans which will decrease the amount of sediment entering the May Creek channel and improve water quality. King County has a vested interest in insuring the longevity of the project. 17 10/25/2012 Muckleshoot The project's adjacent properties should demonstrate compliance with the As described in the response to Comment #15, property owners are showing compliance with their Letter Indian Tribe County Code with farm plans that meet the code and minimize their farm plans by ongoing implementation of highest priority items first. · Pa!!e 4 contributions to the sedimentation and flooding problem. 18 10/25/2012 Muckleshoot The project should also evaluate the potential for existing SE 148m Street King County acknowledges that the SE 14810 Street Bridge would not pass the 100-year flood without Letter Indian Tribe Bridge to create an obstruction and create backwater conditions that overtopping the road; however, the goal of ihis project is not to address problems associated with the Page4 causes sediment to deposit upstream. Per the Hydraulic and Hydrologic I 00-year flood event. This project is focused on decreasing flooding for flows slightly less than the 1- Analyses for this project, this bridge cannot pass a 100-year flood _year flow event. Replacing the SE 148th Street Bridge is not within the scope of this project. without overtopping the roadway which suggests that it is restricting flows and contributing to the backwater conditions. 19 10/15/2012 Muckleshoot Details are lacking regarding the flood event needed to connect the The alcoves are intended to enhance winter rearing habitat and are expected to be inundated during the Letter Indian Tribe alcoves to May Creek, ihe corresponding water depths in the alcoves, winter. The alcoves would likely not be inundated during other parts of the year. The alcoves have been Page4 how long they will be inundated and how much rearing habitat would be designed with a 5.5 percent slope towards May Creek to encourage rapid draining at the end of winter. created. If the alcoves are not fully connected to May Creek, or the entire The slope will minimize the risk of fish mortality due to stranding. area is not inundated then the alcoves may provide less habitat than the orooosed 0.24 acres and may potentially result in strandin_g mortalitv. Page 5 December 6, 2012 King County May Creek Drainage Improvement-Joint Public Notice NWS-2010-158 Review Comments and Response • • -. Comment Comment Person/ Agency Comment Response Number Document Commenting 20 10/15/2012 Muckleshoot The project also needs to mitigate for the loss of the full channel King County looked into a number of options for in-stream mitigation downstream of SE 148th Ave. Letter Indian Tribe spanning pool at the Long Marsh Creek confluence. Due to the relatively flat topography at this location, the creation of meandering side channels and side Page5 pools did not prove to be a good option because they would rapidly fill with sediment creating a high risk of stranding during summer low flows .. The alcoves that are proposed proved to be the best way to enhance in-stream habitat with a minimal risk of stranding. In addition, at the request of Washington Department of Fish and Wildlife (HPA 123184-2 Provision #16) King County will be salvaging the existing gravels at the Long Marsh Creek confluence prior to sediment removal. After the sediment is removed in this location, King County will over-excavate and replace at least 18-inches of gravels. The pool at this location is referred to as a Lateral Scour Pool in the Baseline Stream Conditions report (December 20 JO); however, this pool also meets the definition of a Channel Confluence Pool. Since King County will be replacing the existing gravels after the . sediment is removed, and the confluence of Long Marsh Creek and May Creek will remain in this location, it is expected that the existing pool at this location will also exist post-construction. 21 10/15/2012 Muckleshoot A more robust monitoring plan is needed to assess the project's effects on King County is currently proposing to monitor vegetation coverage and survival as stated in Section 6.1 Letter Indian Tribe sediment transport/filling, flooding, habitat creation and riparian planting of the Impact Analysis and Mitigation Plan. King County is also proposing post-construction erosion Page5 success to provide shade and in stream habitat. The alcoves should be monitoring downstream of 148th Avenue SE as described in the Post-Construction Erosion Monitoring monitored to determine the amount of available rearing habitat over a Plan (memo dated August 4, 2011 from Bill Kerschke and Julia Tumey). variety of flow conditions. The project should be monitored for IO years to determined project success (or failure) prior to allowing any new dredging in Mav Creek. Page6 December 6, 2012 .. REPLY TO ATIENTIONOF Regulatory Branch Mr. Doug Chin DEPARTMENT OF THE ARMY SEATTLE DISTRICT, CORPS OF ENGINEERS P.O. BOX 3755 SEATTLE, WASHINGTON 98124-3755 NOV 19 2012 City of Fi Ptann· enton mg Division FEB I 21013 King County Water and Land Resources Division 201 South Jackson Street, Suite 600 ijfE~rEo~{E[[J Seattle, Washington 98104. Reference: NWS-2010-158 King Coµnty (May Creek) Dear Mr. Chin: The following information is provided as a status report regarding the above referenced application. a. A permit decision cannot be made until the following is accomplished: I. A Water Quality Certification is issued by the State of Washington. b. Enclosed are copies of comments received in response to the public notice regarding this permit application. I will need to address those comments raising objections or concerns before a permit decision can be made. To assist me in addressing those comments, I suggest that you follow the procedure in the enclosed Guidance to Applicants for Department of the Army Permits. Comment By Mary Celigoy Janet Norton Andrew Duffus Jean Rollins Dick J. Colasurdo Muckleshoot Indian Tribe Date October 7, 2012 October 23, 2012 October 25, 2012 October 25, 2012 October 23, 2012 October 25, 2012 If you have any questions, please contact me at lori.c.lull@usace.army.mil or at (206) 766-6438. Enclosure Lori C. Lull, Project Manager North Puget Sound Section US Army Corps of Engineers ® Seattle District GUIDANCE TO APPLICANTS FOR DEPARTMENT OF THE ARMY PERMITS 1. GENERAL. The permit process can seem complicated. Please work closely with the project manager identified in the accompanying transmittal letter. Our goal is to reach a final decision on a permit application within 60 days of receipt of a completed application. However, compliance with other Federal laws in special circumstances may extend this period. State or local permitting actions or objections also may delay the final decision. Final comments are normally required from the governmental agencies listed in paragraph 4 within the 30-day review period. We provide you the opportunity to resolve or rebut objections, if any arise. Contacting the objector is voluntary. As a result of objections to your application or other circumstances, such as financial matters, you may request withdrawal of your application. This will not preclude re-submittal of you application at a later date. The following guidance may help you obtain a timely permit decision. 2. PRIVATE PARTIES OBJECTING. You may try to resolve objections by contacting the objector. If objections are resolved, request that the objector withdraw the objections in a letter to the Corps. If objections are not resolved, you may ask us to issue a permit over objections. State your reasons why the permit should be issued over objections. 3. GOVERNMENT AGENCIES. a. WITHHOLDING COMMENT. When agency final comments are withheld, such as when that agency has permit requirements applicable to your project, you should contact that agency and take any necessary action. b. OPPOSITION. You may contact the agency and attempt to resolve the opposition. You may also request that we make a decision on your application over unresolveaoojections. St~a~te ____ _ your reasons why the permit should be issued over objections. c. CONDITIONAL COMMENT. Sometimes an agency may recommend changes to your project or ask that you agree to certain conditions. In such cases, you should contact the Corps to · make us aware that you may be considering the proposal. Remember, while other Federal agencies may make recommendations in light of their agency responsibilities, the Corps of Engineers has the ultimate authority to determine if the proposed project is not contrary to the public interest, whether the permit should be issued or denied, and if special conditions should be added to the permit. -2- 4. GOVERNMENT AGENCY ADDRESSES Environmental Protection Agency Region 10 1200 Sixth Avenue, MIS WD-128 Seattle, Washington 98101 (206) 553-1286 U;S. Department of the Interior Fish and Wildlife Service Ecological Services 510 Desmond Drive SE, Suite 102 Lacey, Washington 98503-1263 (206) 753-9440 U.S. Department of Commerce National Marine Fisheries Service Environmental and Technical Services Division 525 Northeast Oregon Street Portland, Oregon 97232-2737 (503) 230-5400 Sediment Management Unit Department of Ecology Post Office Box 47703 Olympia, Washington 98504-7703 (206) 459-6038 • ., Lull, Lori C NWS From: Sent: To: Subject: Greetings Ms. Lull, Mary Celigoy [maryceligoy@comcast.net] Sunday, October 07, 2012 4:27 PM Lull, Lori C NWS Public comments -NWS-2010-158, King County (May Creek) Mary Celigoy here, owner of The Red Barn on May Valley Road. A lot is ai stake regarding the realization of this project. It is so vital for the future survival of our 65 acre fann that this work is implemented. What we visualize here on our property is the ability to continue to have the pasture space to hold horses. Our amount of acreage and what we use it for is becoming a rare commodity for the equine business. A healthy, happy horse needs space to roam and graze. I have run the business for nearly 20 years now, and have watched the creek become more and more plugged up and the use of the land diminishes as it does so. Reed Canary grass, non only being and invasive and non-native, it chokes oµt what's native and clogs up the stream so much, there's no way any fish could make it's way through. The channel is so thick right now, the ducks don't even swim in it anymore. I have attached a picture to demonstrate how it looks this year. As you'll see when examining the below photos, the creek is not visible. Our fann has so much sentimental value, not just to our family, but! beli~ve to the entire community. I gei comments all the time· from folks, when ihey hear I'm with The Red Barn, that they love driving by the farm. The beautiful historic barn (now on the state's Heritage Barn Registry) and the wide open pastures with the horses grazing is a serene sight for our busy lives to. enjoy. In closing I'd like to thank the many county members, and staff at the King Conservation District, and other hired individuals from different organizations that have been involved over the years at bringing this much needed project doser to fruition. In particular, Doug Chin and his group. I'm sure I know only a fraction of the time they have put into the planning and pennitting of this project. ' . ' Once compleied, a healthy creek and wetlands with native plants can be enjoyed by all the habitat a creek can offer. And at the same time, the fields can dry off quicker to be utilized by the horses (and perhaps cows in the future). Thanks you for your time and consideration. 1 • 2 Lull, Lori C NWS · From:·' Sent: To: Subject: Ms. Lori Lull, Janet Norton Uanet.m.norton@hotmail.com] Tuesday, October 23, 2012 8:37 PM Lull, Lori C NWS May Creek My name is Janet Norton and I am a co-owner of The Red Barn on May Valley Road. Flooding has bee a major problem on our family farm that has only gotten worse every year. When the flooding occurs it takes days for the water to go down. This ruins our pastures and fences. Removing sediment and clearing the Reed Canary Grass will help May Creek flow more freely and reduce. the flooding. The reed Canary Grass has almost choked out the creek and taken wild life of the creek. There are very few working farm left in the area and we would like to preserve May Valley and enjoy May Creek again. Thank You for your consideration, Janet Norton P.O. Box 183 Easton, WA 98925 425 -941 -6333 1 Lull, Lori C NWS From:. Sent: To: Subject: Attachments: Dear Ms. Lull: A DUFFUS [klassicars@hotmail.com} Thursday, October 25, 20121:_11 PM Lull, Lori C NWS Public Notice Reference No. NWS-2010-158. King County (May Creek) ArmyCorps.doc; May Creek residence sandbagged.jpg; May Valley Seasonal Pasture Flooding.jpg; Trees & Property Lost FOREVER.jpg; May Valley Seasonal Floodplain.jpg; Home at RISK.jpg · Please find my questions attached, as well as five (5) photographs. Thanks you for your time. Andrew Duffus 1 9605 143rd Avenue SE Renton, WA 98059-376'> ,.October 25th, 2012 Ms. Lori Lull Project Manager US Army Corps of Engineers · Seattle District Regulatory Branch 4735 East Marginal Way Seattle, WA 98134-2329 VIA E-Mail: lori.c.lull@usace.army.mil RE: Public Notice Reference No. NWS-2010-158. King County (May Creek) Dear Ms. Lull: The decision whether or not to issue the permit for this project is based on evaluation of factors including, " ... economics ... wetlands ... floodplain values ... erosion ... and, in general, the needs and welfare of the people." 1. I am going to limit my comments and questions to the economic cost-benefit analysis, or rather, lack thereof There is a disconnect between the cost and benefit of this proposal. King County Water & Land Recourses Division (W&LRD) proposes to spend over $1.5 million dollars of taxpayer money for a dredging project of limited usefulness. This project will marginally benefit four property owners who raise horses for personal pleasure. The limited benefits of the project far outweigh the enormous cost, (up io $1,555.000) especially in times ofreduced government revenues. W &LRD estimates dredging 2,086 linear-feet of May Creek and associated mitigation will "rise to ... approximately $1.35 -$1.45 million upon completion." Post-construction (monitoring) expenditure is estimated to be $125,000 ... " 2· (Emphasis added.) W&LRD states, "The project is a small project that does the bare minimum to restore the low flow drainage capacity of the stream channel. .. " 3 · (Emphasis added.) · The "Mitigated Determ·ination of Non-Significance" states, "The goal ofthis project is to reduce the duration of flooding on these properties at both the start and the end of the rainy season ... Due to the high groundwater table in May Valley and because there will be no measurable difference in the geographic extent offlooding, it is not likely that this proiect will change the amount o(wet pasture ... 4· (Emphasis added.) · What should be of interest is that King County undertook a similar (albeit smaller) dredging project in this very reach of May Creek in 2002. The County wrote in a letter to this writer that "The pilot project's effects on salmon, flooding, and sediment accumulation were not assessed using scientific methods:" 5· · · . QUESTIONS RE: PROJECT COST-BENEFIT & CRITICAL DOWNSTREAM PROBLEMS: Where is the cost-benefit analysis in terms of taxpayer dollars? That is, an economic analysis of this project's presumed benefits. Not simply "preserving the rural character of a community." 5 · What is the economic value to the four luckv property owners who personally will benefit from this proposal? Why is the W &LRD prop& to spend $1.5 million dollars of tax1,{}r money to dredge a creek and a wetland for the marginal benefit of four private horse pastures? (No homes or other structures are at risk !) The four equine properties abutting this reach of May Creek are assessed at a total taxable land value · of$500,223. The improvements have a total value of $1,328,000. 7· No homes are in danger of flooding or erosion because the original homesteaders, recognizing a wetland when they saw one, sighted their houses and outbuildings well back from the floodplain. Downstream flooding is threatening peoples' homes as opposed to temporarily flooded horse pastures upstream. Downstream erosion is endangering both homes and sole access private bridges. Erosion means loss of property forever! Seasonal flooding of wetland horse pastures is just that, seasonal, i.e. temporary! Repeat, why is the W&LRD prosing to spend $1.5 million dollars oftaxpayei money to dredge a creek and a wetland, while ignoring erosion and flooding downstream? Attached are five pictures that show the plight of downstream property owners versus the pastoral scenes of horses serenely grazing, albeit in a flooded wetland! Who should benefit from limited government resources, horses or people? Sincerely, Andrew Duffus Telno. 425-255-9405 Attachments: Three Photographs downstream properties Two Photographs upstream wetland pastures Footnotes: 1. Joint Public Notice, Dated September 261h, 2012, Page 3. 2. Water and Land Resources Division, Mark Isaacson, Division Director. Letter to Andrew Duffus, . et al, April 2, 2012, page 2 .. 3. Water and Land Resources Division, Doug Chin, PMP, Project Manager, Capital Services Unit. Letter to City of Renton, January 23, 2012, page 1. 4. Water and Land Resources Division, Mitigated Determination of Non-Significance, May Creek Drainage Improvement Project (9Al205), September 8, 2010, Page L · 5. Water and Land Resources Division, Mark Isaacson, Division Director. Letter to Andrew Duffus, et al, April 2, 2012, page 1. 6. Water and Land Resources Division, Mark Isaacson, Division Director. Letter to Andrew Duffus, et al, August 2, 20 IO, page 2. 7. King County Department of Assessments, Tax Roll 2012 Real Estate Values. Why is the W&LRD pr,,_..,Jsing to spend $1.5 million dollars ofb._payer money to dredge a creek and a wetland for the marginal benefit of four private horse pastures? (No homes or other structures ilcre at ~!) . .. The four equine properties abutting this reach of May Creek are assessed at a total taxable land value· of$500,223. The improvements have a total value of $1,328,000. 7· No homes are in danger of flooding or erosion because the original homesteaders, recognizing a wetland when they saw one, sighted their houses and outbuildings well back from the floodplain. Downstream flooding is threatening peoples' homes as opposed to temporarily flooded horse pastures upstream. Downstream erosion is endangering both homes and sole access private bridges. Erosion means loss of property forever! Seasonal flooding of wetland horse pastures is just that, seasonal, i.e. temporary! Repeat, why is the W&LRD prosing to spend $1.5 million dollars of taxpayer.money to dredge a creek and a wetland, while ignoring erosion and flooding downstream? Attached are five pictures that show the plight of downstream property owners versus the pastoral scenes of horses serenely grazing, albeit in a flooded wetland! Who should benefit from limited government resources, horses or people? . Sincerely, Andrew Duffus Telno. 425-255-9405 Attachments: Three Photographs ·downstream properties Two Photographs upstream wetland pastures Footnotes: 1. Joint Public Notice, Dated September 26th, 2012, Page 3. 2. Water and Land Resources Division, Mark Isaacson, Division Director. Letter to Andrew Duffus, -----etal;-April·2;-2012;-page·2. 3. Water and Land Resources Division, Doug Chin, PMP, Project Manager, Capital Services Unit. Letter to City of Renton, January 23, 2012, page I. · · 4. Water and Land Resources Division, Mitigated Determination of Non-Significance, May Creek Drainage Improvement Project (9Al205), September 8, 2010, Page 1. · 5. Water and Land Resources Division, Mark Isaacson, Division Director. Letter to Andrew Duffus, et al, April 2, 2012, page I. 6. Water and Land Resources Division, Mark Isaacson, Division Director. Letter to Andrew Duffus, et al, August 2, 20 I 0, page 2. · 7. King County Department of Assessments, Tiix Roll 2012 Real Estate Vaiues. Lull, Lori C NWS From: Sent: To: Subject: Attachments: Lori, urban separator [urbanseparator@hotmail.com] Thursday, October 25, 2012 5:19 PM Lull, Lori C NWS King County (May Creek) NWS-2110-158 USArmyCorps.doc Attached are my neighborhood's questions and comments regarding the proposed dredging of May Creek. Thank you. Jean Rollins 1 Jean Rollins 2905 Ilwaco Ave NE Renton, WA 98059 Phone: 425-255-9405 October 25, 2012 Ms. Lori Lull Project Manager US Army Corps of Engineers Regulatory Branch P.O. Box 3755 Seattle WA 98124-3755 VIA E-Mail: lori.c.lull@usace.army.mil RE; King County (May Creek) NWS-2110-158 Dear Ms. Lull, Thank you for the opportunity to comment on Project NWS-2010-158, the proposed dredging of May Creek. My neighbors and I have concerns and questions expressed below. It is important to note that this is the second flood control project within this same reach of May Creek in the last 10 years. The first project conducted on the McFarland/Hyak Stables property (now owned by Harold Gambini, Jr.) was completed in 2002. (For exact location, see "Joint Public Notice", 26 Syp. 2012, attachment pages 2 & 3.) The McFarland/Hyak project was so lightly tracked that the County was not able to determine if the project was a success or not. "The pilot project's effects on salmon, flooding, and sediment accumulation were not assessed using scientific methods:" 1. Inli-glltoftneiirst dredging project~s lackufmonitoring;itwourneighborhoods-'insistence-tha---- Project NWS-2010-158 be properly monitored before and after completion. King County Water and Land Resources Division (WLRD) propose to monitor downstream post project conditions for 10 years. 2· We have comments and questions regarding this monitoring. First, in order to compare pre-project condition versus post project conditions, the monitoring sites must be established and baseline data gathered pre-proiect, for at least two (2) water years. The "May Creek Canyon Reach Monitoring Plan " 3· prepared for King County in 2010 recommends that monitoring elements include pressure transducers, cross-section surveys, the placement of bed hooks and/or bank pins and monitoring critical discharge following certain magnitude storm events .. "Two previously established and five new locations are proposed for the current Canyon Reach monitoring effort. In addition, we recommend that Gage 3 7B be reconciled." 3· Gage 37B More specifically the Plan states, " ... that flow monitoring at Gage 3 7B be continued and the gage reconciled such that the data may be used reliably in the future." 4 · Question 3: Has Gage 37 b been reinstalled and reconciled? (' I Monitoring Locations "Each monitoring location shall include either bed hooks, bank pins, or both to monitor erosion or deposition of the bed and erosion of the banks." 5· Question 4: Have each of the seven monitoring sites been established? Questions: Have pressure transducers, cross-section surveys, and the placement of bed hooks and/or bank pins been installed as prescribed at the seven sites? Questions 6 & 7: Which sites have bed hooks installed, conversely which sites have bank pins installed and which sites have both bed hooks and bank pins installed? Are there any field changes or deviations from the Monitoring Plan? Evaluation Post Storm Events Further, the Monitoring Plan goes on to state, " ... each location should be monitored following precipitation events greater than approximately 70cfs." 6· Again, more specifically, "After each critical flow event, monitoring locations shall be investigated for the presence or absence of each of the bed hooks (eye bolts) or exrosure of the bank pins (rebar). Any change to these features shall be measured and documented ... " · Question 8: Has each of the seven monitoring sites been monitored during the past two water years, if so where is the data? Additional Bed Hooks Needed There is evidence of bed movement in the stream channel on Tract A, and the Duffus' and Coates' properties. The proposed project may very well exacerbate streambed elevation, always an on ongoing concern of downstream property owners. Question 9: Why are bed hooks not recommended in this reach? Bed hooks would establish the facts once and for all as to streambed gravel stability or instability during various storm flows. Question 10: Can bed hooks be installed in the reach? Commitment by King County to provide necessary monitoring resources In light of the lack of monitoring of the earlier McFarland/Hyak project, our community does not want to learn, after the fact, that monitoring was not performed as recommended. The Monitoring Plan states that monitoring should be undertaken after any storm event that can be expected to result in a 70 cubic feet per second discharge. If this is not done, there is risk that subsequently observed erosion might be attributed to subsequent storms greater than those of a 70 cfs discharge. The point is, that the purpose of the Monitoring Plan is to establish the definitive threshold of erosion (sediment transport.) Absences of professional observation and timely data will result in erroneous conclusions. Questions 11 & 12: Will the County pledge to commit the monetary and human resources necessary to monitor 70 CFS or greater events both pre-project and post? Further, what assurances of that commitment do the downstream citizen-property owners have? · One final question 13: How will King County WLRD apprise our community of the monitoring efforts of critical flow events? We understand that protocol dictates that the U.S. Army Corps requests answers to our questions from King County Water and Land Resources Division. I respectfully ask that the answers provided by WLRD be forwarded to me so I can share those answers with my neighbors. Summary We expect that the seven monitoring sites to be fully in place before this project goes forward. It is impossible to evaluate any scientific project without appropriate and accurate baseline data. Further, the community expects 2 years of baseline data prior to the project's implementation. We want to be satisfied and assured that the County has dedicated the budget to monitor all seven sites for two years prior and at least 8 years after the project's completion. We request the that the Army Corps postpone issuing permits until 2 years of baseline erosion and flow data has been accumulated and professionally reviewed. Thank You, Jean Rollins 1. Water and Land Resources Division, Mark Isaacson, Division Director. Letter to Andrew Duffus, et al, August 2, 2010 page 2. 2. Water and Land Resources Division, Mark Isaacson, Division Director. Letter to Andrew Duffus, et al, April 2, 2012, page 2. 3. May Creek Canyon Reach Draft Monitoring Plan, Anchor QEA, LLC/King County, December 2010, Page 6. 4. ibid., page 7 5. ibid., page 4 6. ibid., page 2 October 23, 2012 Ms. Lori Lull Project Manager US Army Corps of Engineers Regulatory Branch P.O. Box 3755 Seattle, WA 98124 Dear Ms: Lull, \ . : .. (.. \ . OCT 2 5 ;:r '? Attached is a letter that I drafted in 2001. I have been living on our farm in May Valley for 70 years. It's about time we get some relief from all the flooding that our neighbors and our farm have endured in the past 20 years or so. Please read the enclosed letter that I wrote in December, 2001 regarding my history here on the farm and the flooding of May Creek we've experienced over the years. Thank you, Prepared by: D:t~~ J. Colasurdo 15440 S.E. May Valley Road Renton, WA 98059 Phone: ( 425) 255-3533 1).e c.. t?n-ih e r ifs 2l>O t I To whom it may concern: I have been farming here in May Valley since the early 1940's. Before I moved in, Cosmo Pinchetti had a dairy farm here since around 1910 and before that, it was part of the Elliott Homestead. So this farm has been a productive farm for over 100 years. I had a very successful dairy farm for .· about 25 years. I milked cows in the old barn when I first moved on the · farm. It wouldn't pass for "Grade A" milk, sot built a milking parlor to upgrade the milk from creamery to "Grade A" milk. By doing this, I received a much higher price for my milk which I sold to Alpine Dairy in Issaquah (who later became Darigold). I bought a 1939 Cle Trac bulldozer to clear our land across May Creek. After clearing, I plowed, disced and seeded about 20 more acres. This enabled me to increase my herd to 40 milking cows and about 6 dry cows, 10 heifers and 10 calves. The old barn was too small and old so I built a new barn in 1949. It held 40 milking cows and stored 150 tons of baled hay. I used the old barn for the dry cows, heifers and calves. In 1951, I got a farm loan and had 2 silos built and purchased a 25 sprinkler irrigation system. This enabled me to have 2 cuttings of silage and late fall pasture. I was a charter member of King County Soil Conservation and a member of-King County-Dairymen Association. I received several awards for high_ milk production and followed the soil conservation plan all the years that I had the dairy. I also plowed and disced during that time my adjoining neighbor's farm, Phil Fisher, so he could plant his bean crop every year. It would be impossible to repeat any of my dairying days now with stagnant water staying in over half of our fields which was always classfied as No. 1 pasture land on our Real Estate Taxes back then. Small dairy farms became hard to compete with the much larger farms so I sold the cows and moved on to another business. Then my wife, Anna, kept the farm going by boarding horses. I kept up all of the maintenance work that goes with the farm. Currently, our daughter, Mary (Celigoy) Colasurdo is boarding horses on the farm. The following is a review of May Creek as I have seen it since about 1941. fhe creek was dredged in the summer of 1939 and 1940. The flow of water was moving all the time -this kept the water cool even without shade. All kinds of salmon and steelhead came up to spawn. May Creek was open for juvenile fishing. The Department of Fisheries planted trout off the bridges on 148th Ave. S.E. and 164th Ave. S.E. My 3 girls and all of my nephews, nieces and neighbor children experienced very good fishing during their school years. I worked with Soil Conservation all during the time I was dairying. One practice we had was to keep all the pasture and creek banks mowed for weed control. This kept the brush and reeds canary grass from growing in the middle of the creek and kept the water flowing. We have over 1 / 2 mile of May Creek flowing through our property. It is the only stretch of creek that can be seen as a creek. If there was some kind of maintenance done along these lines, May Creek would not be in such terrible condition as it is now. The salmon and trout have disappeared since about 1975. It is impossible for any fish to swim through all the brush, debris and reeds canary grass that has grown solid through the creek. You can plant trees and shrubs along the banks of May Creek for shade, but keep it out of the middle of the creek. Keep the water flowing, this also keeps the temperature down for the fish and helps to control the flooding. Flooding was no big problem when I was farming. Some years it would not flood at all. It would take a week of heavy rainfall for it to flood. When it did flood, it would be gone in a COl!J>le of da~. I was able to plow and seed any field in the Spring time of the year. These fields were classified as No. 1 pastureland on the Real Estate tax rolls. King County Department of Public Works raised the roadbed below the bridge on 148th A venue S.E. three different times since I have been here. Their purpose was tp keep flood waters off the roadway. Total fill was about three feet. I have pictures showing this fill. The bridge on 148th is still the same size as it was in 1942 so a combination of these two factors would create one gigantic retention pond for the county but would ruin a lot of good pasture land and flooding of some barns. I hope this does not happen. Now it takes at least a month for flood waters to recede and some fields are now wet and ruined for pasture all summer. There is about 20 acres that can no longer be used at all. If we don't get some relief from all this flooding, our farm will no longer be able to operate as a productive farm. • I OCT 2 9 2012 MUCKLESHOOT INDIAN TRIBE 1, Fisheries Division 39015-172"d Avenue SE• Auburn, Washington 98092-9763 Phone: (253) 939-3311 • Fax: (253) 931-0752 October 25, 2012 US Army Corps of Engineers Regulatory Branch Washington Department of Ecology SEA Program P.O. Box 3755 P .O . Box 47600 Seattle, WA 98124-3755 Olympia, WA 98504 Attn: Lori Lull, Project Manager Attn: SEA Pro~am, Federal Permit Coordinator RE: Joint Public Notice, NWS-2010-158, King County (May Creek Drainage Improvement) Dear Ms. Lull and Federal Permit Coordinator: . The Muckleshoot Indian Tribe Fisheries Division (MITFD) has reviewed the Joint Public Notice of Application for King County's proposed May Creek Drainage Improvement Project. This project is the first of potentially four phases to dredge May Creek. In this first phase, the project proposes to dredge May Creek from stream mile 4 .3 to stream mile 4 .9, removing sediments, reed canarygrass, and some of the existing willows that are within the flooded area of concern. As noted in previous comments, our Habitat -Program staff has concerns about dredging May Creek because of potential adverse impacts to salmon and their habitats. The affected reach is identified as salmon spawning and rearing habitat (May Creek Baseline Stream Conditions Report). This project would dredge 2,086 linear feet of streambed and remove reed canarygrass and willows from 14 ,500 square feet from May Creek and its associated wetland. As noted in various project documents, this is the first of potentially four projects that would dredge ofup to 2.26 miles of May Creek, which is 75% of the valley length and 32% of May Creek's entire length. The combined impact of all of these dredging projects · would likely result in a significant loss of existing salmon habitat, and potentially other future adverse impacts upstream and downstream from the dredged reaches as additional landowners seek to protect their properties from bank erosion. We have recommended that King County implement and exhaust all less impacting alternatives prior to dredging May Creek. We remain concerned that this project will 'adversely affect salmon and aquatic habitats without sufficient mitigation for these impacts. The project will impede the natural processes of sedimentation and . floodwater storage along May Creek without a full assessment of potential habitat impacts in the project area and in upstream and downstream areas . In particular, the potential pre-and post-project rearing habitat available for juvenile salmon in May Creek has not been quantified . Jean Rollins ,.2905 Ilwaco Ave NE Renton, WA 98059 Phone: 425-255-9405 October 25, 2012 Ms. Lori Lull Project Manager US Anny Corps of Engineers · Regulatory Branch P.O, Box 3755 Seattle WA 98124-3755 VIA E-Mail: lori.c.lull@usace.army.mil RE; King County (May Creek) NWS-2110-158 Dear Ms. Lull, Thank you for the opportunity to comment on ProjectNWS-2010-158, the proposed dredging of May Creek. My neighbors and I have concerns and questions expressed below. It is important to note that this is the second flood control project within this same reach of May Creek in the last IO years. The first project conducted on the McFarland/Hyak Stables property (now owned by Harold Gambini, Jr.) was completed in 2002. (For exact location, see "Joint Public Notice", 26 Sep. 2012, attachment pages 2 & 3:) The McFarland/Hyak project was so lightly tracked that the County was not able to determine if the project was a success or not. "The pilot project's effects on salmon, flooding, and sediment accumulation were not assessed using scientific methods:" L -----1rn-lighrofthe-first-dredging·project's-lack-ofmonitoring;-it·is'our·neighborhoods'-insistence·that----- Project NWS-2010-158 be properly monitored before and after completion. King County Water and Land Resources Division (WLRD) propose to monitor downstream post project conditions for IO years. 2· We have comments and questions regarding this monitoring. First, in order to compare pre-project condition versus post project conditions, the monitoring sites must be established and baseline data gathered pre-proiect. for at least two (2) water years. The "May Creek Canyon Reach Monitoring Plan" 3· prepared for King County in 20 IO recommends that monitoring elements include pressure transducers, cross-section surveys, the placement of bed hooks and/or bank pins and monitoring critical discharge following certain magnitude storm events .. "Two previously established and five new locations are proposed for the current Canyon Reach monitoring effort. In addition, we recommend that Gage 37B be reconciled.?' 3· Gage 37B More specifically the Plan states, " ... that flow monitoring at Gage 3 7B be continued and the gage reconciled such that the data may be used reliably in the future." 4 · · Question 3: Has Gage 3 7 b been reinstalled and reconciled? Monitoring Locations "Each monitoring location shall include either bed hooks, bank pins, or both to monitor erosion or deposition of the bed and erosion of the banks." 5· Question 4: Have each of the seven monitoring sites been established? Questions: Have pressure transducers, cross-section surveys, and the placement of bed hooks and/or bank pins been installed as prescribed at the seven sites? Questions 6 & 7: Which sites have bed hooks installed, conversely which sites have bank pins installed and which sites have both bed hooks and bank pins installed? Are there any field changes or deviations from the Monitoring Plan? Evaluation Post Storm Events Further, the Monitoring Plan goes on to state, " ... each location should be monitored following precipitation events greater than approximately 70cfs." 6· Again, more specifically, "After each critical flow event, monitoring locations shall be investigated for the presence or absence of each of the bed hooks (eye bolts) or exr.osure of the bank pins (rebar). Any change to these features shall be measured and documented ... " · Question 8: Has each of the seven monitoring sites been monitored during the past two water years, if so where is the data? Additional Bed Hooks Needed There is evidence of bed movement in the stream channel on Tract A, and the Duffus' and Coates' properties. The proposed project may very well exacerbate streambed elevation; always an on ongoing concern of downstream property owners. Question 9: Why are bed hooks not recommended in this reach? Bed hooks would establish the facts once and for all as to streambed gravel stability or instability during various storm flows, Question 10: Can bed hooks be installed in the reach? Commitment by King County to provide necessary monitoring resources In light of the lack of monitoring of the earlier McFarland/Hyak project, our community does not want to learn, after the fact, that monitoring was not performed as recommended. The Monitoring Plan states that monitoring should be undertaken after any storm event that can be expected to result in a 70 cubic feet per second discharge. If this is not done, there is risk that subsequently observed erosion might be attributed to subsequent storms greater than those of a 70 cfs discharge. The point is, that the purpose of the Monitoring Plan is to establish the definitive threshold of erosion (sediment transport.) Absences of professional observation and timely data will result in erroneous conclusions. Questions 11 & 12: Will the County pledge to commit the monetary and human resources necessary to monitor 70 CFS or greater events both pre-project and post? Further, what assurances of that commitment do the downstream citizen-property owners,have? .: One final question 13: How will King County WLRD apprise our community of the monitoring efforts of critical flow events? We understand that protocol dictates that the U.S. Army Corps requests answers to our questions from King County Water and Land Resources Division. I respectfully ask that the answers provided by WLRD be forwarded to me so I can share those answers with my neighbors. Summary We expect that the seven monitoring sites to be fully in place before this project goes forward. It is impossible to evaluate any scientific project without appropriate and accurate baseline data. Further, the community expects 2 years of baseline data prior to the project's implementation. We want to be satisfied and assured that the County has dedicated the budget to monitor all seven sites for two years prior and at least 8 years after the project's completion. We request the that the Army Corps postpone issuing permits until 2 years of baseline erosion and flow data has been accumulated and professionally reviewed. Thank You,· Jean Rollins I. Water and Land Resources Division, Mark Isaacson, Division Director. Letter to Andrew Duffus, et al , August 2, 20 IO page 2.- 2. Water and Land Resources Division, Mark Isaacson, Division Director. Letter to Andrew Duffus, et al, April 2, 2012, page 2. 3. May Creek Canyon Reach Draft Monitoring Plan, Anchor QEA, LLC/King County, December 2010, Page 6. 4. ibid., page 7 5. ibid., page 4 6. ibid., page 2 October 23, 2012 Ms. Lori Lull Project Manager US Army Corps of Engineers Regulatory Branch P.O. Box 3755 Seattle, WA 98124 Dear Ms. Lull, OCT 2 5 2n::1 ',i.. Attached is a letter that I drafted in 2001. I have been living on our farm in May Valley for 70 years. It's about time we get some relief from all the flooding that our neighbors and our farm have endured in the past 20 years or so. Please read the enclosed letter that I wrote in December, 2001 regarding my history here on the farm and the flooding of May Creek we've experienced over the years. Thank you, ., Prepared by: D,_.~ J. Colasurdo 15440 S.E. May Valley Road Renton, WA. 98059 Phone: (425) 255-3533 J)e> c. G'rn hei,-1 g-'2 ,~ r) I . I To whom it may concern: I have been farming here in May Valley since the early 1940's. · Before I moved in, Cosmo Pinchetti had a dairy farm here since around 1910 and before that, it was part of the Elliott Homestead. So this farm has been a productive farm for over 100 years. I had a very successful dairy farm for . about 25 years. I milked cows in the old barn when I first moved on the· farm. It wouldn't pass for "Grade A" milk, so I built a milking parlor to upgrade the 1nilk from creamery to "Grade A" milk. By doing this, I received a much higher price for my milk which I sold to Alpine Dairy in Issaquah (who later became Darigold). I bought a 1939 Cle Trac bulldozer to clear our land across May Creek.. After clearing, I plowed, disced and seeded about 20 more acres. This enabled me to increase my herd to 40 milking cows and about 6 dry cows, 10 heifers and 10 calves. The old barn was too small and old so I built a new barn in 1949. It held 40 milking cows and stored 150 tons of baled hay. I used the old barn for the dry cows, heifers and calves. In 1951, I got a farm loan and had 2 silos built and purchased a 25 sprinkler irrigation system. This enabled me to have 2 cuttings of silage and late fall pasture. I was a charter member of King County Soil Conservation and a member ----of-King-County-Daicymen.Association._Lreceiv:ed.sev:eraLawards..for_high ____ _ milk production and followed the soil conservation plan all the years that I had the dairy. I also plowed and disced during that time my adjoining neighbor's farm, Phil Fisher, so he could plant his bean crop every year. It would be impossible to repeat any of my dairying days now with stagnant water staying in over half of our fields which was always classfied as No. 1 pasture land on our Real Estate Taxes back then. Small dairy farms became hard to compete with the much larger farms so I sold the cows and moved on to another business; Then my wife, Anna, kept the farm going by boarding horses. I kept up all of the maintenance work that goes with the farm. Currently, our daughter, Mary (Celigoy) Colasurdo is boarding horses on the farm. ..;.; .The following is a review of May Creek as I have seen it since about 1941. 'The creek was dredged in the summer of 1939 and 1940. The flow of · water was moving all the time -this kept the water cool even without shade. All kinds of salmon and steelhead came up to spawn. May Creek was open for juvenile fishing. The Department of Fisheries planted trout off the bridges on 148th Ave. S.E. and 164th Ave. S.E. My 3 girls and all of my nephews, nieces and neighbor children experienced very good fishing during their school years. I worked with Soil Conservatfon all during the time I was dairying. One . practice we had was to keep all the pasture and creek banks 1nowed for weed control. This kept the brush and reeds canary grass from growing in the middle of the creek and kept the water flowing. We have over 1/2· mile of May Creek flowing through our property. It is the only stretch of creek that can be seen as a creek. If there was some kind of maintenance done along these lines, May Creek would not be in such terrible condition as it is now. The salmon and trout have disappeared since about 1975. It is impossible for any fish to swim through all the brush, debris and reeds canary grass that has grown solid through the creek. You can plant trees and shrubs along the banks of May Creek for shade, but keep it out of the middle of the creek. Keep the water flowing, this also keeps the temperature down for the fish and helps to control the flooding. Flooding was no big problem when I was farming. Some years it would not flood at all. It would take a week of heavy rainfall for it to flood. When it did flood, it would be gone in a couele of day_s._I_w_a_s_a_b_l_e~t_o _____ _ plow and seed any field · in the Spring time of the year. These fields were classified as No. 1 pastureland on the Real Estate tax rolls. · King County Department of Public Works raised the roadbed below the bridge on 148th Avenue S.E. three different times since I have been here. Their purpose was to keep flood waters off the roadway. Total fill was about three feet. I have pictures showing this fill. The bridge on 148th is still the same size as it was in 1942 so a combination of these two factors would create one gigantic retention pond for the county but would ruin a lot of good pasture land and flooding of some barns. I hope this does not happen. Now it takes at least a month for flood waters to recede and some fields are now wet and ruined for pasture all summer. There is about·20 acres that can no longer be used at all. If we don't get some relief from all this flooding, our fann will no longer be able to operate as a productive farm. · The problems we , having due to flooding is hM J the same for . everybody with property on May Creek. Solving these problems are of ·. the upmost importance to May Valley's residents and it is why there is such large turn-outs at the Basin Plan meetings. These people are very active for a reason -the valley is our home, and in a number of cases including ours, the valley is our livlihood. My daughter, Mary, and I have cooperated in the past by allowing the County to plant trees and shrubs along the banks of the creek and fencing 20'. from the creek on both sides. By doing this, we lost about 2 acres of pasture. We also fenced off areas for horses to stay in during the winter months being they can't go out to pasture because· of the flooding and muddy conditions. . . The King County Council approved the May Valley Basin Plan in April of this year. All the property owners in our valley were relieved that finally our flooding prob1erns would be resolved. For the Fall of 2001 the plan . called for cleaning out the trouble areas in the ditch to allow the water to start flowing again. But nothing was done because DDES would not issue any kind of a permit to do this. This was to be followed by removal of silt from the creek in the fall of 2002. So we are gravely concerned because if a permit was not issued for just cleaning out the trouble spots, then will a permit really be issued for next year to clean the silt out of the entire creek? We are left feeling discouraged and fearful that this basin plan will go by the wayside like the others in the past. ' ·, ·~·.s::c··r:.,; ··--:·----~ :u~-~f-:.,\lt:~D I . . . -. -, I OCT 2 9 2012 MUCKLJESHOO'f :n:ND:n:AN 'ffilBJE ·, Fisheries Division 39015 -172nd Avenue SE • Auburn, Washington 98092-9763 Phone: (253) 939-3311 • Fax: (253) 931-0752 October 25, 2012 US Army Corps of Engineers Regulatory Branch P.O. Box 3755 Seattle, WA 98124-3755 Attn: Lori Lull, Project Manager Washington Department of Ecology SEA Program P.O. Box 47600 Olympia, WA 98504 Attn: SEA Program, Federal Permit Coordinator RE: Joint Public Notice, NWS-2010-158, King County (May Creek Drainage Improvement) Dear-Ms. Lull and Federal Permit Coordinator: The Muckleshoot Indian Tribe Fisheries Division (MITFD) has reviewed the Joint Public Notice of Application for King County's proposed May Creek Drainage Improvement Project. This project is the first of potentially four phases to dredge May Creek. In this first phase, the project proposes to dredge May Creek from stream mile 4.3 to stream mile 4.9, removing sediments, reed canarygrass, and some of the existing willows that are within the flooded area of concern. As noted-in previous comments, our Haoitat Program staff lias concerns al:iouCdreclging May Creel< because of potential adverse impacts to salmon and their habitats. The affected reach is identified as salmon spawning and rearing habitat (May Creek Baseline Stream Conditions Report). This project would dredge 2,086 linear feet of streambed and remove reed canarygrass and willows from 14,500 square feet from May Creek and its associated wetland. As noted in various project documents, this is the first of potentially four projects that would dredge ofup to 2.26 miles of May Creek, which is 75% of the valley length and 32% of May Creek's entire length. The combined impact of all of these dredging projects· would likely result in a significant loss of existing salmon habitat, and potentially other future adverse impacts upstream and downstream from the dredged reaches as additional landowners seek to protect their properties from bank erosion. We have recommended that King County implement and exhaust all less impacting alternatives prior to dredging May Creek. We remain concerned that this project will adversely affect salmon and aquatic habitats without sufficient mitigation for these impacts. The project will impede the natural processes of sedimentation arid floodwater storage along May Creek without a full assessment of potential habitat impacts in the project area and in upstream and downstream areas. In particular, the potential pre-and post-project rearing habitat available for juvenile salmon in May Creek has not been quantified. Mu2kleshoot Indian Tribe Fisheries Division Habitat Program Comments to Public Notice NWS-2010-158 October 25, 2012 Page 2 of5 For those impacts that have been quantified, the project impacts exceed the proposed mitigation in length and area. While the proposal to fence and plant the affected reach with native wetland/ riparian vegetation. and create alcoves with wood and sediment would iinprove existing habitat conditions, the extent of these mitigation measures is insufficient to mitigate for the potential loss of 48,000 square feet of instream habitat resulting from dredging. We note that the proposed 15' planting buffer width is narrower than the 25' buffer in the land use rules for existing pasture (King County Code 21.A.30.045.B) and substantially less than the regulated buffer (i.e. 165' per King County regulations for fish-bearing waters), and will not provide full riparian functions as a result. · Additional mitigation is required to fully mitigate for unavoidable environmental impacts. The following measures should be implemented as additional mitigation: I. Promotion and adoption of agricultural best management practices, farm conservation plans, and other measures as appropriate to improve pasture conditions and to control sediment sources; 2. Increase the stream/wetland buffer width to a minimum 25 foot buffer width per the County Livestock Ordinance and increase riparian planting in the project areas; 3. Commit to mitigate any unavoidable impacts to fish habitat in downstream areas that result from the project. 4. All of the mitigation areas need to be permanently protected in a conservation easement or other protective mechanism with King County providing monitoring and maintenance of the mitigation areas. Overall, we are concerned that this project represents only a "short term fix" to address flood concerns in May Valley. There is a high likelihood that additional dredging will be proposed in the future in May Creek or its associated wetlands resulting in cumulative and ongoing impacts to fish and fish habitat. The proposed plantings to eventually shade out reed canary grass where they are planted reducing sediment accumulation and providing a more sustainable approach to localized flooding. However, a long term approach is also needed to reduce flood risks and future dredging. Therefore, we recommend that the applicant take further steps, including the mitigation measures listed above, to reduce the obvious land use and pasture-related sediment sources while providing May Creek with floodway/floodplain area to store and transport its sediment load, consistent with natural stream processes. · ·'1· Muckleshoot Indian Tribe Fisheries Division Habitat Program Comments to Public Notice NWS-2010-158 October 25, 2012 Page 3 ·or 5 Additional specific comments and questions about this project are attached for your review and consideration. Please let me know if you have any questions at 253-876,3116. Sincerely, h~~ Karen Walter Watersheds and Land Use Team Leader Cc: Randy McIntosh, NMFS Larry Fisher, WDFW Region 4 Jennifer Henning, City of Renton Planning Doug Chin, King County DNRP Jamie Hartley, King County ODES ,· Muckleshoot Indian Tribe Fisheries Division Habitat Program Conunents to Public Notice NWS-2010-158 Other Potential Approaches to reduce sediment inputs October 25, 2012 Page4 of5 Most of the properties to benefit from the project are used for livestock pasture. King County Code (Title 21 A.30) regulates these areas to "support the raising and keeping of livestock in the county in a manner that minimizes the adverse impacts of livestock on the environment particularly with regard to their impacts on water quality and salmonidfisheries habitat in King County watersheds". As part of the Code compliance, property owners are required to have a farm plan with maximum densities of livestock. The farm management plans should also achieve a "minimum 25 foot buffer of diverse, mature vegetation between grazing areas and the ordinary high water mark of all type S and F aquatic areas and the wetland edge of any category L II or III wetland with the exception of grazed wet meadows, using buffer averaging where necessary to accommodate existing structures!' The proposed mitigation buffer for dredging is a maximum of 15 feet, which is substantially less that the County Code. The project's adjacent properties should demonstrate compliance with the County Code with farm plans that meet the code and minimize their contributions to the sedimentation and flooding probiem. The project should also evaluate the potential for the existing SE 148th Street Bridge to create an obstruction and create backwater conditions that causes sediment to deposit upstream. Per the Hydraulic · and Hydrologic Analyses for the project (KC 2010), this bridge cannot pass a 100-year flood without overtopping the roadway which suggests that it is restricting flows and contributing to backwater conditions. Project Impacts and recommendations We are concerned that the existing juvenile salmon rearing habitat in May Creek will be lost through the combination of channel dredging, reed canarygrass removal, and removal of in-water and adjacent willows. There is no estimate given for the potential loss of rearing habitat in the project area, where King ---eounty-staffhas·documented·coho·juveniles-(KG--20H-)-. -Cfhe-lmpact-Analysis-and-Mitigation-Plan-(KG---- 2011) indicates that willows will be removed from six existing pools and will eliminating these pools. Channel complexity that creates slower velocity habitat will also be reduced in Reach Two. Per KC (2011), "willow branch complexes have taken 15 to 20 years to establish themselves in this manner and would not replicate pool-forming functions within a few growing seasons." As noted in Table 2, there will be 1.03 acres of permanent instream impact to May Creek and 14,500 • square feet of permanent buffer impact. The project proposes out-of-kind mitigation by enhancing approximately 3 acres of wetland enhancement; 0.24 acres of off-channel alcove creation; and almost 2 acres of riparian and wetland buffer planting along May Creek upstream of 148th Avenue SE. The instream impacts exceed the mitigation (1.03 acres of instream impact to 0.24 acres of stream mitigation) · and will likely result in unmitigated impacts to existing rearing habitat for juvenile salmon. In addition, details are lacking regarding the flood event needed to connect the alcoves to May Creek, the corresponding water depth in the alcoves, how long they will be inundated, and how much rearing habitat would be created. If the alcoves are not fully connected to May Creek or the entire area is not inundated, then the alcoves may actual provide less habitat than the proposed 0.24 acres and also may potentially result in stranding mortality. Muclleshooi Indian Tribe Fisheries Division Habitat Program Comments to Public Notice NWS-20 I 0-158 October 25, 2012 Page 5 of 5 The project also needs to mitigate for the loss of the full channel spanning pool at the Long Marsh Creek confluence. This pool will be eliminated by the stream dredging and not replaced based on the proposed mitigation plans. Since pools are limited in this portion of May Creek per the May Creek Baseline Stream Conditions Report, the pool should be replaced,.potentially downstream of SE 148th adjacent to the mitigation site and NGPE tract for the Stonegate Subdivision where there are fewer constraints to adding wood to form pools. Alluvial fans are natural features at Long Marsh Creek and farther upstream at Indian Meadow Creek. According to the sediment assessment report, these features have been documented in the May Creek Valley since 1872. As a result, they will likely be continued sources of sediment to May Creek. The benefits from the project's work on Long Marsh Creek may be limited due to existing culverts, limitations to restoring the alluvial channel, and the functionality of the new side channel. The project should be fully monitored to determine if the treatments on Long Marsh Creek were successful in storing the predicted amount of sediment. . The project may also aggravate existing conditions for water temperature and dissolved oxygen in May Creek .. Currently May Creek through the May Valley is shown as"Category 2" water for temperature and dissolved oxygen on Ecology's 2008 303(d) list. The removal of vegetation along 0.6 miles of May Creek that currently provides shade will likely worsen this condition. Stream temperature and dissolved oxygen monitoring should be part of the monitoring plan. A more robust monitoring plan is needed to assess the project's effects on sediment transport/filling, flooding, habitat creation and riparian planting success to provide shade and instream habitat. The alcoves should be monitored to determine the amount of available rearing habitat over a variety of flow ---conditions-. -'Fhe·project-should-be-fully-monitored-for-10-years-to-determine-project-success.(or-failure.)--- prior to allow any new dredging in May Cr~ek. ... II/lay Creek Drainage Improvement Project (9A1205) Construction Water Quality Protection and Monitoring Plan Federal Project NWP-210-158 King County Department of Natural Resources and PaCR$ty of R Water and Land Resources Division Plannin 0 enton g 1v1s1on Revised September 7. 2011 FEB 1 2 LU)J Table of Contents I. Plan Purpose ............................................................................................................... 1 2. Water Quality Criteria ................................................................................................ 1 3. Monitoring Plan .......................................................................................................... 2 4. Water Quality Protection Measures ............................................................................ 4 Figure 1: May Creek Water Quality Sampling Locations During Construction ................ 7 .1. Plan Purpose In order to ensure that construction of the May Creek Drainage Improvement Project does not exceed water quality standards as established by federal, state, and local laws and regulations, the King County Water and Land Resources Division has developed this plan for in-stream water quality protection and monitoring during construction. Specifically, water quality criteria contained within Washington Administrative Code (WAC) 173-201A-030(2), l 73-201A-040, and l 73-201A-l l 0(3) apply to this project. The project is located in May Creek (WRIA 08-0282) and the surrounding wetland on the south side of SE May Valley Road between approximately River Mile 4.3 and 4.9 (Figure I). Construction activities consist of removing accumulated sediment and flow obstructing vegetation (primarily reed canarygrass and willow) from May Creek, reconstructing the confluence of Long Marsh Creek and May Creek, and planting riparian and wetland vegetation as compensatory mitigation. The purpose of the monitoring plan is to ensure that silt and sediment generated by project construction activities does not affect water quality in violation of project permits and applicable regulations. Erosion control best management practices (BMPs) are proposed and will be implemented to protect water quality within May Creek. Water quality monitoring will be performed to confirm the effectiveness of the BMPs. 2. Water Quality Criteria Washington State WAC 173-201 A establishes criteria for surface waters of the state. The Department of Ecology may allow a temporary area of mixing during and immediately after necessary in-water construction activities that result in the disturbance of in-place sediments. This temporary area of mixing is subject to the constraints of . WAC l 73-201A-200(1 )(e)(i) and can occur only after the activity has received all other May Creek Drainage Improvelt Project (9Al205) Water Quality Pro.on and Monitoring Plan necessary local and state permits and approvals, and after the implementation of appropriate best management practices to avoid or minimize disturbance of in-place sediments and exceedances of the turbidity criteria. Summer low flows in May Creek and Long Marsh Creek are below 10 cfs (the annual mean flow in May Creek is 8.6 cfs) and therefore the point of compliance for the temporary area of mixing shall be 100 feet downstream from the construction activity per WAC 173-201A-200(l)(e). Turbidity Turbidity will be monitored for this project per WAC 173-20 IA-200(l)(e). At the point of compliance, turbidity shall not exceed: o 5 NTU over background when the background is 50 NTU or less; or o A 10 percent increase in turbidity when the background turbidity is more than 50NTU. Other Parameters Dissolved oxygen, the 7-day average of the daily maximum temperatures (7-DADMax), and pH will not be monitored for this project because the construction activities are not expected to affect these parameters. 3. Monitoring Plan Sampling Locations The folJowing sampling points (SP) (Figure I) will be used for monitoring. Because this is a linear project that extends for approximately 2,000 feet, and multiple stream bypasses wiJJ be needed, the sampling points in May Creek will change as the project proceeds. o SP! {upstream location): Samples will be taken in May Creek 100 feet upstream of the work area before construction begins and wiJJ continue to be taken at the same time as the point of compliance samples (SP3) during the construction activities. o SP2 {upstream location): During work at the Long Marsh Creek confluence, Samples will be taken in Long Marsh Creek 100 feet upstream of the work area before construction begins and will continue to be taken at the same time as the point of compliance samples (SP3) during the construction activities. o SP3 (downstream point of compliance): Samples will be taken in May Creek I 00 feet downstream of the work area before construction begins (to establish baseline conditions) and wilJ continue during construction activities. Additional sampling points may be used on an as needed basis. 2 .,. .. May Creek Drainage Imprc .• ment Project (9Al205) Water Quality , .otection and Monitoring Plan Sampling Frequency Immediately prior to in-water work, baseline sampling will be performed at SP!, SP2, and SP3 in order to obtain representative values for background water quality in the stream. Once construction activity has commenced in an area, water quality data will be collected at each sampling point using a water monitoring device. The monitoring device will be used to collect data every 15 minutes during the construction period. Monitoring will not be performed when the contractor is not working (typically evenings, weekends and holidays). For water quality monitoring purposes, "final stabilization" is defined in the Construction Stormwater General Permit as "the establishment of a permanent vegetative cover, or equivalent permanent stabilization measures (such as riprap, gab ions or geotextiles) which prevents erosion. Once the project has implemented the final stabilization measures, the likelihood that it will contribute sedimentation to the stream is small; therefore, monitoring will no longer be necessary. Field Sampling and Analysis Procedures To evaluate the state water quality criteria, samples will typically be taken in-stream using a YSI, a Hach 21 OOP turbidimeter, or other equivalent monitoring device. The monitoring device will be calibrated and operated in accordance with the manufacturer's specifications. During all sampling, care will be taken to not disturb the streambed or bank, which could contaminate the samples. Samples will be taken in approximately the middle of the stream, at mid-depth. During construction activities that have the potential to affect turbidity, King County staff will be onsite to collect and review water quality data. If the data being collected indicate that state water quality standards are being exceeded, the project's Certified Erosion Control and Sediment Lead (CESCL) will immediately be contacted. The contractor will be directed to stop work while the reason for non-compliance is determined. If the non-compliance is due to construction activities, the contractor will be directed to take the following potential corrective measures before being allowed to resume work: o Immediate maintenance of existing erosion control facilities o Implementation of additional erosion control measures o Diversion of any stormwater away from exposed areas o Suspension of all work activities until more favorable conditions exist The contractor will determine which contingency measures should be implemented and will submit the proposal to the CESCL for review and approval. Once the contingency measures have been implemented, King County staff will monitor water quality to ensure that compliance with water quality standards have been achieved. The CESCL will 3 May Creek Drainage lmprove!lt Project (9A1205) Water Quality Pro.on and Monitoring Plan document corrective measures taken in the project's Stormwater Pollution and Prevention Plan (SWPPP). Monitoring Personnel King County Water and Land Resources Division will provide staff to perform water quality monitoring. Long-term Data Storage and Reporting All water quality monitoring data collected during construction will be recorded electronically and downloaded into an excel spreadsheet later in the office by project staff. If no exceedances are detected, the results of the water quality sampling should be sent on a monthly basis to Rebekah Padgett at Washington Department of Ecology. If any exceedance is detected it should be reported to Washington Department of Ecology within 24-hours with the following information: a. A description of the nature and cause of exceedance. b. The period of non-compliance, including exact dates, duration, and times and/or the anticipated time when the Applicant will return to compliance. c. The steps taken, or to be taken, to reduce, eliminate, and prevent recurrence of the non-compliance. d. In addition, within five (5) days after notification of an exceedance, submit a written report that describes the nature of the exceedance, turbidity results and location, photographs, and any other pertinent information. 4. Water Quality Protection Measures The following Best Management Practices (BMPs) will be utilized to protect water quality in May Creek and the associated wetland during construction. I. Construction Equipment Access a. Construction entrances will be stabilized using quarry spalls and geotextile fabric under the spalls. This will minimize track-out onto the roadway. b. Only low impact rubber tired or tracked construction equipment will be used to access the stream and to transport the sediment. This equipment will move over the reed canary grass and/or pasture grass with minimal disturbance. Equipment will be operated from the stream bank. Construction equipment access points to the stream will be limited in the field to avoid the removal of mature trees. c. Equipment staging areas will be located outside the regulated stream and wetland buffers. Silt fence will be installed around the perimeter of the staging areas to prevent sediment-laden runoff from leaving the area. 4 ... May Creek Drainage Irnptc .rnent Project (9Al205) Water Quality. ,otection and Monitoring Plan d. Temporary paths used for construction equipment access will be restored to original or better conditions once construction is complete, using an appropriate upland or wetland seed mix. 2. Stream Diversion a. To protect downstream water quality, sediment and reed canary grass removal shall be done in the dry by bypassing the stream around the construction area. Approximately I 00 to 500 feet of stream will be bypassed at a time. The contractor will submit a bypass plan to King County for review and approval at the pre-construction meeting. b. Prior to installing the bypass, a biologist will relocate any aquatic life in the channel to a safe location upstream via hand-netting or other accepted methods offish removal (following WSDOT Fish Exclusion Protocol and Standards, dated 2006). c. The stream flow will be bypassed by installing a coffer dam on the upstream end of the construction area and using a sump to pump the flow from the coffer dam to a location downstream of the construction. d. Prior to reintroducing the flow to the newly excavated channel, a second coffer dam and sump will be installed at the downstream limits of the construction area. To ensure that state water quality standards can be met, flow will be introduced to the newly excavated channel, and turbid water will be pumped out at the downstream end of the construction area, and will be discharged to a vegetated upland area, until the water flowing through the channel meets state water quality standards. At that point, the cofferdam and sump will be removed and the flow will be allowed to continue downstream into the undisturbed channel. e. To promote infiltration, a perforated pipe will be used to disperse the pumped turbid water over a vegetated upland area. If the vegetated upland area receiving discharge becomes saturated, the water will be pumped to a Baker tank, or equivalent, and disposed of offsite. f. If it is not possible for the water flowing through the newly excavated channel to meet water quality standards within a reasonable amount of time, then contingency measures may be implemented to decrease sedimentation and turbidity. These measures may include bringing in streambed gravel for the channel or placing a biodegradable erosion control blanket in the bottom of the channel. 3. Sediment Transport and Drying Areas a. Excavated sediment will be transported from the stream channel in a Crawler Carrier, or similar tracked or rubber tired hauling equipment. During transport, the sediment will be carried in the sealed tub of the 5 May Creek Drainage Improve!lt Project (9Al205) Water Quality Pr.on and Monitoring Plan Crawler Carrier. This sealed tub will contain any sediment-laden water. In the unlikely event, that sediment-laden water does leak out of the tub, the following additional BMPs may be used: 1. Lining the tub with plastic to prevent leakage ii. Using sand bags, or a similar plug, at the back end of the carrier to prevent water from spilling out the back b. Sediment that is not saturated will be spread directly on the disposal sites, shown in the plans and will be stabilized by applying a native seed mix. Silt fence will be installed around the sediment disposal area to further minimize the possibility of sediment reaching the stream or wetland prior to the seed mix reaching 80 percent coverage. c. Sediment that is saturated will be transported to the soil drying area. A sump will be installed in the soil drying area, and excess turbid water will be pumped to a vegetated upland area. To promote infiltration, a perforated pipe will be used to disperse discharged water over the area. If the vegetation area becomes saturated, water will be pumped to a Baker tank or equivalent. 4. Construction of Wetland Alcoves along May Creek a. When excavating adjacent to the stream channel on the west side of 148th Avenue SE, an earth plug shall be left between the existing stream channel and the excavation area. Prior to removing the earth plug and connecting the excavated channel, a turbidity curtain shall be installed to protect the stream from sedimentation and turbidity. b. Before removing the turbidity curtain, suspended sediment in the water behind the turbidity curtain will be allowed time to settle out. 5. Other Best Management Practices a. Clearing limits will be clearly flagged prior to construction. No disturbance will be allowed outside the clearing limits. · b. In-stream sediment and vegetation removal will occur only during the work windows designated in the permit to protect aquatic species. c. The temporary erosion and sediment control facilities will be inspected daily by the CESCL and maintained by the contractor. d. A King County staff member will be onsite at all times during construction activities to monitor in-stream water quality and ensure compliance. 6 •' Figure 1: May Creek Water Quality Sampling Locations During Construction ··r c' ( ; ~-. t' ' ,. • ·-" -· Note: Work Area and water quality ~ ---=. "1<:: -l ·_<:;:-.,: ~ r:._...\W~-"'t-;~ I o 12s 2so -<'s.' '~-., -~l· 500 750 Feet "'"""'----""""'"""'",_..,,.-~--..... ,., ~-,. "" r ... ..!< :'".7-'·. ·.··~ c_l, \ .... l!'~t_~~•-;I ~ ~-~. ;"!~J ... :· .. tj1.? ": ,~-.,,,r .·;~-L.:1A.t _ · 1,.h1:-·n:. tt't"i+t:~ -~.: \··. f-t, ·_· ! :.:~-~ ~- \ sampling locations (SP1 and SP3) will 1 . move as work proceeds downstream. r ' I .. H <,~;;,. :?"~ _ -~-·r· / -. '-·I/_ ··,-,·r.1·' + N '~:, _r:::·;.:°'..i,",, ,-.~ :c~. --.,.:'4°.f_./:'1· ;}~ r..,..l!1,,.r11 . . ~ ·,/ 0 : .Yb • . . , o;;J ··k?: -\· -~.-~ .. >" r ·' ,..._ ~~-~-1 ••. ·}JS~".· ).(. 4-f\. . ~·; ,· v-' J' -, __ ._ .• , ft ,,., 1" l'' · ::. ; .: "· .~ ,~,.~ _· 3 . . 'f~ Si:: .t·L.4. . ' · .:X ,;,,; r,• ·,I) -·---". --~ ,, ) legend! 0 Project Area Limits City Boundaries o River Miles o Water Quality Sampling Locations July 12, 2011 ' ;:; ;~"·:ft':'' · · ---...... !:r~ ..... :s::.., -\ ..... _ f· '> • \:r )', i >. ' ~\"' v, ,. ·. ... ... s.~ ·} The information induded on this map has been con'4)iled by King county etafftrom • V8rletyofsooro::a end is subject to change without notice. King COUnty makes no rep1M«1talions or warranties, express or~. as lo accuracy, ~sa, l!m9l*1ess. or rights lo the UH of $UC:h lnbmri::n. Thb document is notinlllnded for use a a ......,.y product King COUnty shall not be liable for any geraal, special. rldlrec:t, inadental, or oonsequenlial darr,e,ga Including, but • not limiled lo, lost revenues or lost profits !'Mulling from the .•. use or miause of the lnfonnallon contained on thla map. MY _. ell Im map or Information on lhi• map Is prohibited e:.tC1'pl: by Wfitlen pennisslon of King Gou:'rty, ~ King County ,-- Figure 1: May Creek Water Quality Sampling Locations During Construction Legend • Project Area Limits City Boundaries o River Miles e Water Quality Sampling Locations July 12 , 2011 0 125 250 500 750 Feet --- Tho...,_lnc:ludodonhamapi.s-.~by King Coln)' -from • wriely.,, -..-and ii at,jact lo dlanga--KingColny-ro--0<----- or ffl)lied. u lo ac:ancy, COff'll)lell,ne ...,._,or~ lofleuseolauot,-. Thia documanl ii ncl inlendad lor --...... y prodUct. IGng Cooo!y-ncl be -for -II"-· opodal, 1n-. lnddantal, or conaequ---Inducing. but not limllOd lo, loot ,_,.,.. 0< io.t p,ofls mulling from fie use 0< -of the lnlorma1lon contained on this mop. Nf1 -d Ns map« lnbmatlon on Ilia map lo poohlbitad ex<>opl by---cA !<mg C<u>ty. UI King County ' \_,- ,, ,r .....,_ I May Creek Phase4Monitoring / May Creek Phase 4 Monitoring (DRAFT) December, 2010 to? Section 1 Section 2 Table of Contents Project Description and Location Map On-Going Monitoring Reports 1 MayCreek Phase 4 Monitoring e Section 1 Project Description and Location Map Location of May Creek Monitoring Program: Note: Thefol/owingfigure transposes Tract A and Tract D. Right and left bank are referenced looking downstream . .. .., + tCJ0-4110111,wv ...... J ... -....---CJ ,,_ """"'" ......... --~l.-~ _..,... _ _ ...,..,._,.Trantta Description of Proposal: The Phase 4 Monitoring effort is a continuation of the 2007-2009 May Creek Phase 1 Monitoring effort. The Phase 1 monitoring plan was developed by Anchor Engineering and implemented by both Anchor Engineering and King County. The Phase 1 study monitored three transects; Site 1 (the furthest downstream transect) had been discontinued during Phase 1 due to braided channel flow conditions and recurrent vandaljsm at this site. Site 3 (Broussard) has been discontinued at the start o f Phase 4 study due to 2 MayCreek Phase4 Monitoring property owner access issues. The only site included in the Phase 4 work (from the original study) is site 2, the Parhaniemi/Gambini site, which is reference as the Gambini site in this document. Anchor Engineering and KPFF Consulting Engineers we re retained by King County to develop both the Phase 1 and Phase 4 monitoring plans for the Canyon Reach of May Creek downstream of 148th Avenue SE. The Phase 4 monitoring effort will gathers upplemental data to be used to identify and document potential impacts from upstream project implementation, building upon the prior monitoring effort implemented during Phase I of the project. The following table, which was taken from the MAY CREEK CANYON REACH MONITORING PLAN SEDIMENT TRANSPORT STUDY PHASE 4, dated 12/2010 by Tracy Drury (Anchor Engineering), defines the monitoring elements to be re-implemented, refined, or discontinued. New procedures and elements of the plan a re also described, and new monitoring I ocations a re identified to build on the data collected in the previous study. The phase 4 monitoring plan will be implemented by County staff. The following table shows two previously-established transects and five new transects a re proposed for the phase 4 Canyon Reach monitoring effort. In addition the Anchor Engineering Phase 4 monitoring plan recommends that Gage 378 be reconciled. The plan also recommends a cross-section surveys hould be completed for each transect. Monitoring Site Monitoring Elements Bank Sets of Location Hooks/Pins PT BH BP Right Left Parhaniemi 0 0 . 0 0 0 1 Tract A {Broussard) 0 0 0 1 Duffus Right Bank 0 0 3 Duffus Lett Bank 0 1 Tract D 0 0 0 2 Cole 0 0 0 2 5tonegate I ract 0 0 0 2· Note: o The Tract A (Broussard) site was discontinued because the property owner denied access. 3 MayCreek Phase4 Monitoring • o The Stonegate site was not surveyed when the study was implemented (for the 2011 wateryear) due to high water conditions at the transect. o The new sites added to the Phase 4 work are Duffus (3 transects), Coats, Tract D and Stonegate; this Tota Is 6 new sites. All of the new sites, as recommended from the Anchor Study, include bank pins, but no bed hooks. 0 So as notto confusethis study (the Phase 4 work) with the original Phase 1 study, the newtra nsects wi 11 be designated by the property owner name, with the three Duffus Transects labeled U, M, and L (upper middle and lower). 0 The pressure transducers have been removed from the original sites. A new flow gage (37H) has been installed at the top of the ravine at the Elwaco Avenue crossing. Phase 4 Monitoring Rainfall Events (12/2010 to ___ ): Monitoring: The last Phase 1 Monitoring was completed on 1/29/2009. This monitoring effort was done followingthe 1/8/2009 storm. The results from this monitoring are included in the Phase I Monitoring Report Early Start Phase 4 Monitoring completed 12/10/2010. This work was completed prior to implementation of the Anchor Engineering Phase 4 monitoring plan. The ea rlystart work was done as an attempt to gather baseline information prior to an anticipated large rainfall event. The flow on 12/10/2010, the day of the monitoring was about45 cfs; two days later on 12/12/2010 the 4 May Creek Phase 4 Monitoring ,_.,, "da i lyflow rate", as published by Ki ngCounty, was 221 cfs. The following pictures a re from the 12/10/2010 monitoring, which was 2 days prior to the rainfall event. The Ga mbini transect (Site 2) was surveyed, but the flows in the stream were too high to place the bed hooks and bank pins . The monitoring, along with the channels urvey, includes visual inspection of the site. The Ga mbini site showed no noticeable difference in the channel shape atthe cross-section, nor did it show any vis i ble erosion upstream or downstream of the cross -section since the end of the previous (1/29/2009) phase one monitoring. The Broussard transect (Site 3) had noticeable lateral migration of the channel as can be seen in the photos. Duri ng the monitoring visit, the newtenant had concerns with the planned May Creek work, and after discussions with King County management he rescinded the approval for a ccessto the site. Monitoring at this reach has since been cancelled . The follow-up reconnaissance after the rainfall event was completed after the high water receded following an extended wet period i n the area . The follow-up monitoring occurred on 2/7/2011 and is discussed i n the fol lowing monitoring write up. Ga mbini 12/10/2010 (Site 2) Inspection and Survey. Broussard 12/10/2010 (Site 3)-Site Abandoned . 5 () May Creek Phase 4 Monitoring 2/7/2011 Start of Phase 4 Monitoring King County Staff, Tim Kelly and Larry Goulet re-started the May Valley monitoring, which is now titled May Creek Phase 4 Monitoring. Monitoringof MayCreek/Gambini Transect , 2/7/2011 Tim Kelly and La rryGoulet, We a th er 48 and overcast. General Notes : The water was clear with the channel bottom visible; the water level has receded from the recent heavyra ins, which can be seen in the photos . The cross section does not appear to have changed as 5 of the pins from the Phase 1 study were observed in their original position. The section of stream where the hooks where not located a ppearto be a tthe same elevation (no down-cutting). We surveyed the cross section on 12/10/2010 (discussed previous), once the study is completed the cross section will be surveyed to see if there has been any change in the channel geometry. We also located the bank pins from the o r iginal study, this had very I ittle exposed re -bar, so the channel has not moved I aterallyatthis location (see photo). As pa rt of re-occupying the transect we installed4 new bank pins: 2 pins in the right and left bank at approximate same location as the original study. The bank pins a re #4 re bar painted with alternating black/orange bands at 0.1' intervals. We also placed 8 hooks, the first two (toward the right bank looking downstream) we re the original hooks from the old study, we did not have to re-place them. The remaining hooks are placed at 3' intervals. The attached photos are from the set-up for Phase 4 monitoring at MayCreekdone by Tim Kelly and Larry Goulet at the Gambinl site on 2/7/2011. Ga mbini 2/7/2011: Set 2 new bank pins at right bank nea r the original Site 2 bank pins. 6 May Creek Phase 4 Monitoring Ga mbini 2/7 /11: Transect in the same location as the original Site 2 w/bed hooks @3' intervals. 2/10 and 2/11/2011 Survey to Initialize New Transects (Start of Phase 4 Monitoring) King County Staff, Tim Kelly and Larry Goulet started the s urveyforthe May Creek Phase 4 Monitoring. The weather was in the high 40's , mostlyove rcast with sun breaks . The attached photos are from the survey work to set-up for Phase 4 monitoring at May Creek. The work included survey of the Coates, Tract D, Stone Gate 7 May Creek Phase 4 Monitoring ' ' and three Duffus transects and placement of bank pins a tthese I ocations. Stone Gate was not completed due to high wateratthetransect. On Thurs day and Friday we installed bank pins in three locations on The Duffus site, one location on the Coates site and one location on the Tract D site. Atthe Coatess ite we Installed 2 pins into the right bank just below the end ofa retaining wall. On the Upper Duffus site we installed 2 pins i ntothe right bank at as harp left-hand bend in the stream just below the Coates site and 2 pins in the same right bank near the end of this bend (Middle Duffus transect). The three transects, Upper Duffus, Middle Duffus and Coates, the re bar bank pins were hammered into vertical earthen banks with a bout 0.2' of the re bar exposed. A third transect on the Duffus property (Lower Duffus Transect) was placed at a sharp right-hand bend in the stream at the lower end of the Duffus parcel. This transect has 2 bank pins installed into the left bank just upstream ofa lateral bank cut and deep pool on Tract A. Al I bank pins are number3 om umber 5 re bar 24" in length. The re bar a re driven almost flush with the vertical eroded banks. Each re bar is painted with alternating orange and black bands, each band being0.1 foot in length to more easily determine the a mount of lateral movement after a significant storm. Ape rson can vi suallycountthe number of tenths ofa foot of lateral movement from the top of the bank without going into the stream to measure them when the water is too deep or too swift. On the Tract D site we installed 1 bank pin into the low eroding left bank and 1 vertical pin on the right bank to monitor lateral movement. Because the eroding banks have very I oosematerial they began to unrave I and coll apse as we were driving the pins. At each location we installed a pin within the I owerone foot of the bank and a pin half way up the bank. • The transect atthe Pa rhaniemi/Gamblni site uses the same control rebarthat we installed for the originals tudy. • The Coates, Duffus upper and the Duffus middle has a single transect nearthe middle pins with a hub on top of the right bank set 10 feet from the eroded edge and a hub and tack with a I ath at the top of the I eft bank. • The Duffus lowertra nsect has a re baron the right bank and a lath at the top of the left bank. • The Tract D transect is at some bed cutting a little way upstream of the bank pins with a rebarin the top of the I eft bankand a lath on the right bank. • At the Stonegate site we shot in a control re bar at some higher ground on the left side of the stream. Because the water is still a ways over the top of the banks we could not drive any bank pins atthis location and did not complete a tra nsectformonitoring. General Notes: The water was clear but deeper in the upper reaches of the study area. The streambed is sandy gravel with a lot of cobbles and some slightly I arger boulders. At the Coates and Duffus sites the banks are a bout 10' high. There is significant erosion on the right bank at the I eft-hand bend. The bank material is very loose sandy gravel with cobbles and some larger boulders embedded. The banks slough off easily when dri1o1ng the bank pins. At the Tract D site the banks a re much lower, 5' high. The left bank has a horizontal bank pin. 8 May Creek Phase 4 Monitoring The right bank has a vertical bank pin at the top because the eroded bank is undercut and underwater. The transect location has fairly large boulders in the bed. Downstream the bed has some deep pools. At the Duffus and Coates sites Mr. Duffus indicated that he would check the bank p i ns at these 41 ocations after any significant rain fall and E-mail this i nfoto WLRD staff (Tim Kelly). His property has a security fence and gate and it is not convenient for countystaffto be enteringon a regular basis. The following photos depict the location of the newtra nsects upstream of the Broussard transect. Additional photos and the survey data a re available from King County Water and Land Resources Division Project Management and Design Unit. The fourtra nsects located on the Duffus and Coates property can be accessed vi a a gated property. The property owner, Andrew Duffus, has expressed an interest in inspectingthe four transects and will forward his observations for indusion in the document. These fourtra nsects a re readily accessible from his property and each transect include the addition two bank pins that a re p ieces of number 2 reba r painted an alternating orange/black at 0.1' i nterva Is. The bank pins a re hammered nearly flush (generally0.2') with the surface on typically near vertical banks. The pins will require visual observation after storm events (and photo documentation) of the bank movement as recorded by the length of exposed re bar. The bank pins a re placed on the outer stream meander of the existing eroded bank (ass hown in the photos). Lower Duffus 2/10/11: Control Point in Duffus lawn, Transect located just downstream . Lower Duffus 2/10/11: Note Duffus lawn in background.Transect in dudes bed pins left bank only. 9 May Creek Phase 4 Monitoring Middle and Upper Duffus and Coates2/11/11: Three transects along same shown bank. 10 ----~ --------, ~-\ May Creek Phase 4 Monitoring Tract D 2/11/2011: Two verti ca I bank pins I eft bank and one horizontal pin on the right bank. Stone Gate 2/11/2011: Survey not completed due to hig h water levels. 4/26/2011 Phase 4 Monitoring of May Creek/Duffus Transect The three transects, including two on the Duffus property and one on the Cole property a re located in a gated area that is monitored by Andrew Duffus, the property owner. Thefollowingemail was an end of water year report emailed by Mr. Duffus with regard to the three transects . At least two of the pins are now exposed more than three -tenths {3/10ths) of a foot. Probably from the storm s of late March -early April when the flow gauge recorded up to 92 cfs . A follow-up email was requested asking for photos and specifics on which bank pins a re experiencing bank migration. When this information is made available it will be added to the report. 11 I ; ' May Creek Phase4 Monitoring 5/2/2011 Phase 4 Monitoring of May Creek/Gambini Transect Tim Kelly and La rryGoulet, Weather 53 degrees, overcast with light rain. General Notes: The water was clear with the channel bottom visible; the water level has receded from the recent rains . The cross section does not a ppearto have changed. Al I the bed hooks were observed in their original position. There was no change in the bank pins. Ga mbini 5/2/11: No Change in Transect. 12 King County CityofR Ptanntn _enton g D1v/sion FEB 1 2 ZOIJ Road Services Division Materials Laboratory Department of Transportation RSD-TR-0100 155 Monroe Avenue Northeast, Building D Renton, WA 98056-4199 www.metrokc.gov/roads fRi IE {C IEUr,;fE ft)) October 12, 2010 TO: David Funke, Engineer II, Hydraulic Data Collection Group, Water and Land Resources Division, Department of Natural Resources and Parks VIA: Alan rJHforwin, PE, Materials Engineer, Materiais Laboratory, Engineering Services Section, Road Services Division, KCDOT FM: Dennis Armstrong, LEG, Engineer II, Materials Laboratory, Di4 Engineering Services Section, Road Services Division, KCDOT RE: Report of Monitoring Well Installation May Creek Valley between 148th Avenue SE and 155th Avenue SE King County, Washington Representatives of Water and Land Resources Division (WLRD) and the King County Materials Laboratory (KCML) installed five groundwater monitoring wells at the above referenced location on September 7, 2010. The general site location is shown on the attached Vicinity Map of the Study Area (Figure 1 ). The locations of the monitoring wells are shown on the attached Monitoring Well Location Map (Figure 2). Background and General Site Conditions May Creek flows generally westward in the bottom of May Valley. Floodi~ in the valley has be an ongoing problem for property owners along May Creek between 143 Avenue SE and 164th Avenue SE. King County is undertaking a study in the area to evaluate alternatives to alleviate the flooding. Information collected on the ground/surface water will contribute to the overall study. Monitoring Well Construction Five monitoring wells were constructed. at locations identified by WLRD staff. The monitoring wells were constructed by hand augering a shallow boring al each well location. Hand augered well depths varied between 2.5 to 3.5 feet in depth. Boring logs describing the soil conditions encountered during excavation of each monitoring well are attached as Figures 3 through 7. Clean sand was placed at the bottom of the well excavation to a depth of 2 to 4 inches. The well screen was capped and placed In the excavation with the riser pipe coupled to the top of the screen. The well screen length ranged between 1.4 and 2.2 feet. The top of the screen was located 0.9 feet below the ground surface. Clean sand was used to encase the well screen and a portion of the coupling above the screen. Bentonite chips were added above the sand to form a well seal. The well head cover was inserted into the seal and permanently set in place with May Creek Summary97201 O .doc Thomas Brothers Reference Page 626 and 627 A and J.3 May Creek Monitoring Well Construction May Creek Area • October 12, 2010 Page 2 of 2 concrete. A recording device was placed in each monitoring well to measure the change in water levels. After placement of recording equipment the well was closed and the cap locked in place. The monitoring wells are located in three general areas. .The first area (KCMW-1 and KCMW-2) is along 1481h Ave SE near the intersection with SE May Valley Road. General soil conditions consisted of sod and top soil to a depth of 2 to 2.5 feet. At KCMW-1, sand with silt was encountered below the topsoil to the final depth excavated of 3.3 feet. No groundwater was encountered at KCMW-1. In KCMW-2, below the topsoil we encountered organic silt with sand lenses and scattered wood debris and roots to the total excavated depth of 3.5 feet. Water was found at 3.0 feet below the surface. The second area (KCMW-3 and KCMW-4) is located near the landmark designated as "The Red Barn". The ground surface at both locations had been previously disturbed to a depth of 0.4 feet and consisted of wood chips (Hog Fuel) and topsoil. Below the disturbed surface soils we encountered silty clay (KCMW-3) and organic silt (KCMW-4) that extended from 2 to 2.5 feet below the surface. KCMW-3 terminated in silty sand at a depth of 2.8 feet. KCMW-4 terminated in loose organic silt with roots and scattered wood debris at a final depth of 2.5 feet. Groundwater was encountered in KCMW-3 at a depth of 2.6 feet and in KCMW-4 at a depth of 2.3 feet. The third area is located 0.1 O miles east of "The Red Barn" along SE May Valley Road. A driveway providing access to pastures in the valley bottom below SE May Valley Road is found 0.1 O miles east of "The Red Barn". The access road includes a bridge over May Creek. KCMW-5 is located along the driveway 20 feet west of the north end of the bridge over May Creek. During the excavation of KCMW-5 we encountered medium dense silty sand with gravel that was classified as fill for the abutment for the farm bridge. The fill extended from the existing ground surface to a depth of 2.6 feet. The monitoring well was terminated below the fill in wet silty sand with gravel at a depth of 3.5 feet . Groundwater was encountered at 3 feet below the surface. Summary The monitoring wells were Installed following procedures outlined in the Washington Administrative Code Chapter 173-160, Minimum Standards for Construction and Maintenance of Wells. If you should have further questions please contact Dennis Armstrong at 206-296-8204. Attachments Figure 1 -Vicinity Map of the Study Area Figure 2 -Monitoring Well Location Map Figure 3 -Log of Monitoring Well Installation KCMW-1 Figure 4 -Log of Monitoring Well Installation KCMW-2 Figure 5 -Log of Monitoring Well Installation KCMW-3 Figure 6 -Log of Monitoring Well Installation KCMW-4 Figure 7 -Log of Monitoring Well Installation KCMW-5 May Creek Summary 97201 O.doc · / Vicinity Map of May Valley Study Area lOG4IF MONITOR WELl INSTA' ATION WELL NO. KCIVIW-1 PROJECT: May Creek Project BORING LOCATION: 148th Ave SE at the May Creek Bridge DRILL METHOD: Hand Auger DRILLER: King County DATE: September 7, 2010 START: 10:30 AM 9/7/2010 FINISH: 11 :15 AM 9/7/2010 LOGGER: D. A. DEPTH TO -Water: N(A I ELEVA'fiOR/ I BOIL SDIBOUI IWIPLER SYIIBOL8 D!:P'l'B AND FIBLD HST DATA 100 --0 u--1 98 --2 . . L 97 _.L.,_ 3 . 96 _L_' L ... ~. L ... ' . L DATE CHECKED: N/A uses Deoodption ---------------------Sod and topsoil. · · ------·-.;..;; ________ ;... ____ ._ OL Black organic silt with sand, moist, loose. (Topsoil) ,lloiat -200 c,, (%) • L-.--L-, ________ ....;, ________ ' . SP Brown to gray poorly graded san1 with silt, moist, loose. Nonitor well C:cmatruetlon Sahmlatio - . •; i... ' ~ •, lo •• ~:· ~:~ .. •• . .. . . ' .•; lo: • . •, . . •, .. · . • ~. i,. •••• • . •, . •, . :_:.·. :: - :•. . ::· .: . . •, .. .·. . . . ,' •: .· . . •, . . ~ .. " .... • .. - a . . ', - . NOTES Monitoring well KCMW-1 is located 97 feet south of the south bridge abutment and 32 feet east of the road-way center line. Washington State Department of Ecology discrete obseNation well tag number BCB 334. Figure 3 KING COUNTY MATERIALS LABORATORY lOG r-,MONITOR WIElL n~S1Alll' --rioN WELL NO. KCl\llW-2 PROJECT: 1\/lay Creek Project BORING LOCATION: 148th Ave SE at the 1\/lay Cree!< Bridge DRILL METHOD: Hand Auger DATE: September 7, 2010 START: 11:15 Al\ll 91712010 FINISH: 12:00 Pl\ll 91712010 LOGGER: D. A. DRILLER: King County · DEPTH TO • Water: 3.0 DATE CHECKED: During Drilling ~A'fJ:021/ son snmoLs SAIOLD. SYMBOLS DBHB Alm l'IJ:LD TEBi" DATA 100 0 . H 1 . 98 2 H 4 ., . " .. uses fil fil llO-lp~C>D ----------------Sod and topsoil. ---------------Black organic silt with sand, moist, loose. (Topsoil) Black organic silt with thin sand lenses and scattered wood debris, wet, loose. aolat -200 , .. , , .. , Konitor Woll acmaxtua Conatructioa Sohe&t.io . .· . •. . . . . ~: . . . . . . . . . . . '• . . . . . : : .. . . . . . . . . . . . . . . .• . . .. · ...... · ..... .. •· .. . . . . . .. . . . . . . . . N O T E S Monitoring well KCMW-2 is located 239 feet north of the north bridge abutment and 86 feet east of the road-way center line. Washington State Department of Ecology discrete obseNation well tag number BCB 335. Figure 4 KING COUNTY MATERIALS LABORATORY LOG' F i\llOl\ff'IJ"OIR WIELL INSTA' ATION WELL NO. KCMW-3 PROJECT: May Creek Project BORING LOCATION: Field Northwest of the Red Barn DRILL METHOD: Hand Auger DRILLER: King County DEPTH TO -Water: 2.6 BL.BVATIORI 80:CL SD!BOLS SAIIPLD SYIIBOLS .. ~ DZPTB AID) F:c&LD 'l'BST DATA .100 ii H . 1 ?.7 . 3 H ' ,s _ s· -.--------·-------Bark mulch. Black silty clay, moist, medium stiff. ' ·-------------Brown silty sand, wet, loose. DATE: September 7, 2010 START: 1:45 PM 9n/2010 FINISH: 2:30 PM 9/7/2010 LOGGER: D. A. DATE CHECKED: During Drllllng ISDJ.ot -200 . <") ,_; 111emitor Well ~ Ccmatruation Sohematio . . . ~-. . . . •, . . . . . . . . . . •.. '!: : : . . . . . . . . . . . . . . N O T E S Observation well KCMW-3 is located along a fence line 405 feet west of the west end of the Red 8am and 166 feet south of SE May May Valley Road. Washington State Department of Ecology discrete observation well tag number BCB 336. Figure 5 KING COUNTY MATERIALS LABORATORY LOG (\MONITOR WIELL INSfAlt 0-l/'ION WELL NO. KCMW-4 PROJECT: May Creek Project BORING LOCATION: Field South of the Red Barn DRILL METHOD: Hand Auger DRILLER: King County DEPTH TO -Water: 2.3 BLEVATXOU/ son. SYtmOLS UJDLEJ\ SYIIIBOLB VSC8 DZn'8 UD FDLD TZST DD.TA. 100 0 OL. 99 1 ML ML ML •99 .2 - ·97 3 H 4 .. s 9d • Doaad.ption Sod and topsoil. Black organic silt with sand, moist, soft. Brown silt, wet, soft. (Volcanic AshL ___________ _ J!rown san!:!Yyilt,yetL..loose. _ Gray silt, wet, loose. The silt contained organic material including roots and sticks. DATE: September 7, 2010 START: 2:45 PM 9/7/2010 FINISH: 3:30 PM 9/7/2010 LOGGER: D. A. DATE CHECKED: During Drllllng &lat -200 ,... , ... IIOnitor Woll Conotrvotion Sahmmtia . . . . . •· . . . . . . . . . . . . . . . . . .. ,· . . . . . . . . ·• . ... ·• . N O T E S Monitoring well KCMW-4 is located 606 feet south of May valley Road along a farm access road and 62 feet east of a farm bridge over May Creek. Washington State Department of Ecology discrete observation well tag number BCB 337. Figure 6 KING COUNTY MATERIALS LABORATORY / ! . '• lOC 1F i\1101\llTOR WELl 11\lSTA ATION WELL NO. KCMW-5 PROJECT: May Creek Project BORING LOCATION: II/lay Valley Road East of the Red Barn DRILL METHOD: Hand Auger DATE: September 7, 2010 START: 12:15 PM 9/7/2010 FINISH: 1 :30 PM 917/2010 LOGGER: D. A. DRILLER: King County DEPTH TO • Water: 3.0 100 _ .a H .i . 18 2 " : 3 H : ' Is , JJ NOTES DATE CHECKED: During Drilling SOIL -·BDIBOLS I IIAIIPLD:~ ,IISCS I AID>:.Pmi> 'ft:ft WA ---------------Sod and iOJ?.SOih -----. - Brown silty sand with gravel and occasional cobbles; moist, medium dense; (FiU) Gfay silty. ;-and with gravel, wet,. loose. troiat .;.200 ., .. , :(ti) l:IOllitor·Well Coziatn.otion SOliemaua · · . . . . . . : :, ·: . . . . . .. . . . . . . •. . . . .. . . •' .. .. . . . . . :: : . . ~: . . . .. . . ..... . . . . . . . ... .. . . .. . . . ·• . . . . . . . ~ .. /.· . . . . . . . . -.. Monitoring well KCMW-5 is located along SE May valley Road 0.10 Miles east of the Red 8am. 136 feet south of SE May Valley Road along a farm access road and 20 feet west of a farm bridge over May Creek and Washington State Department of Ecology discrete observation well tag number BCB 338. Figure 7 KING COUNTY MATERIALS LABORATORY ~!EV 1J"(O) ~YM!BlOIL~ " Symbol Description Strata symbols Topsoil ' Symbol Description Low plasticity organic silts Poorly graded sand Silty sand Silt Bark Mulch Low plasticity clay Misc. Symbols T -=- End of boring Water table during drilling .Monitor Well Details riser with cover and protective casing Notes1 protective casing set in concrete D f:11] LlJJ 00 EID f::7::l ~ bentonite pellets silica sand, blank'PVC slotted pipe w/ sand silica sand, no pipe (end plug) 1. The :moitoring wells were excavated and installed September 7, 2010, using hand equipment. 2. Groundwater was encountered in four of the five monitoring wells. Depths to the water surface are shown on the monitoring well logs • . 3. The wells are located in relation to l~Bth Avenue Southeast, May Valley Road, and the Red Barn adjcent to May Valley Road. ~. These logs are subject to the limitations, conclusions, and recommendations contained in this report. t.", ... -~ King County City of Renton Planning Division Water and Land Resources Division · Department of Natural Resources and Parks King Street Center 201 South Jackson Street, Suite 600 Seattle, WA 98rn4-3855 206-296-6519 Fax 206-296-0192 TTY Relay: 711 April 25, 2011 FEB 121UU TO: Lori C. Lull, Project Manager, Seattle District Corps of Engineers FM: Doug Chin, Project Manager, King County Water and Land Resources Division RE: King County May Creek Alternatives Analysis (NWS-2010-158) King County Water and Land Resources Division proposes to remove sediment and instream vegetation within portions of May Creek in the May Valley in order to reduce overbankflooding and increase conveyance of May Creek (project purpose). This will decrease the duration of flooding to adjacent pastures, thereby increasing the time that pastures are useable by livestock. May Creek in this area is nearly flat and flows through large wetlands, many of which are currently used as horse pastures. Overbank flooding during small storm events is .limiting the historical farm use of these properties. The alternatives developed to address this project purpose were based on flood reduction potential, potential to increase useable pasture area, cost, and property owner willingness. The majority of the alternative~ were derived from the May Creek Drainage and Restoration Plan (GeoEngineers 2008). This plan summarizes past, current, and projected future conditions in the May Creek Ba5in, inventories proposed actions planned in the basin, and recommends dozens of conceptual projects to address local flood control issues, degraded aquatic habitat, and other associated issues in the May Valley. Five action alternatives and the no-action alternative have been identified to address flooding problems in the May Valley. The recommended alternative is described first, followed by four other action alternatives that are not recommended, and finally the no- action alternative. Table 1, provided at the end of this analysis, compares the alternatives. Alternative 1 -May Valley Drainage Improvement (Recommended Alternative) Description The recommended alternative is a comprehensive approach to addr.ess drainage issues in May Valley and includes the following elements: May Creek Alternatives .. lysis (NWS-2010-158) April 25, 2011 Page 2 • I. Removing invasive (reed canary grass) and other channel blocking vegetation from May Creek 2. Removing accumulated stream sediment at select locations in May Creek to a uniform elevation of 308 feet 3. Planting a 15-foot buffer of riparian/wetland vegetation on each side of May Creek 4. Fencing the 15-foot planted buffer to exclude livestock access to the stream 5. Controlling sediment from Long Marsh Creek by restoring natural alluvial fan processes and creating a side channel along May Creek 6. Restoring instream and riparian habitat features at Long Marsh Creek 7. Enhancing wetland fish habitat by creating off-channel alcoves along May Creek Impacts Impacts from this alternative include alteration and removal of existing instream habitat in May Creek by the removal of sediment and vegetation. Some existing riparian cover will also be removed and replaced with different varieties of native vegetation that is less likely to grow into the stream channel. Even though the vegetation that is being removed is being replaced, temporal impacts will occur since it will take 5 to 10 growing seasons to replace the lost function. Construction equipment access will temporarily impact the wetland and floodplain. Meeting the Project Purpose This alternative meets the project purpose by removing instream obstructions (sediment and vegetation), which will increase conveyance and channel storage, therefore decreasing overbank flooding. Practicability This alternative is practicable for multiple reasons. First, it allows property owners to reclaim more useable pasture at certain times of the year, without requiring them to move their operations to another location. The sediment and vegetation removal does not require land acquisition, and therefore the proposal fits within the King County budget. The proposal does not require permanent fill in the wetland, stream, or floodplain (except streambed gravels for mitigation). In addition, the mitigation associated with this proposal will protect the stream by restoring native riparian/wetland vegetation and installing fences along the stream which will prevent livestock access. Design Variations Considered The recommended design was selected after analyzing varying amounts of vegetation and sediment removal to determine the amount needed to provide a reduction in duration of flooding for the most frequent, smaller storm flows (i.e., less than a I-year event). Selecting an alternative that targets small storms is unlikely to have any significant impact on the larger storms capable of causing downstream erosion. Additionally, the proposed conveyance improvement achieved by the selected design should be able to prevent build-up of silts and fines, thus improving the sustainability of the project. Other design variations did not provide the level of reduction in the duration of flooding desired or they could not sustain the channel improvements without on-going maintenance. ,. May Creek Altemativto Analysis (NWS-2010-158) April 25, 2011 Page3 Alternative 2 -Restore Floodplain Description t,•' This alternative would involve purchasing private property within the regulatory stream buffer (165-feet on either side of the stream) and restoring the floodplain and wetland in this area. This alternative would involve purchasing land and would require that property owners relinquish existing pasture in the buffer. Impacts This alternative would have a beneficial effect on May Creek, the surrounding wetland, and the JOO-year floodplain, because natural processes would be restored for 165-feet on each side of the stream. However, this alternative would have a negative effect on private property owners, because owners would be required to move their existing farm practices out of the restored 165-foot buffer area. Meeting the Project Purpose This alternative does not meet the project purpose of reducing overbank flooding and increasing the conveyance of May Creek. Instead this alternative eliminates the need to reduce overbank flooding and increase conveyance of May Creek, because farm practices would be reduced or eliminated within the floodplain. Most of the properties in May Valley currently exercise their remaining farm practices within the floodplain. Practicabf/lty This alternative is not practicable due to the large amount of private property that King County would need to purchase. Funding is not available for property purchases of this magnitude, and even if funding were available, the private property owners have not expressed interest in relocating their existing land uses to another location. Alternative 3 -Flood Control Berms Description This alternative would involve constructing earthen berms along May Creek to contain overbank flooding. Berms would be approximately two to three feet high and seven to eight feet wide depending on location. The berms would extend the time for dry pasture use without removing sediment from the stream but would not prevent flooding during large storm events. Impacts This alternative would require placing fill for the berm in the I 00-year floodplain and associated wetland, and would further disconnect May Creek from its floodplain. This alternative would have more adverse impact on the May Creek, the surrounding wetland, and the 100-year floodplain than the recommended alternative because it involves placing a large of amount of permanent fill in these waterbodies. May Creek Alternatives li1ysis (NWS-2010-158) April 25, 2011 Page 4 Meeting the Project Purpose • This alternative meets the project purpose because it would decrease overbank flooding, and would increase conveyance of May Creek. Practicability This alternative is not practicable due to the amount of impact that it would have on May Creek, the wetland, and I 00-year floodplain. The amount of compensatory mitigation required to offset these impacts would be cost prohibitive to the project. In addition, the proposal does not follow the required mitigation sequence (avoid first, minimize second, and compensate last). It does not avoid and minimize. Federal, state, and local permitting agencies would be unlikely to issue a permit to place such a large amount of permanent fill in these waterbodies for this purpose, when other less environmentally damaging alternatives exist. Alternative 4 -Upland Stormwater Controls Description This alternative would involve purchasing property and constructing upland regional stormwater retention/detention facilities to regulate storm flows. The most promising sites would need to be large enough to capture high volumes of storm water and release flows at a very low rate in order to reduce flooding. Alternatively, several smaller facilities (instead of one large facility) could potentially provide equivalent reductions in flow. Impacts This alternative would eliminate the need to place fill in the stream, wetland, and floodplain. However, it would involve capturing a large portion of the flow of May Creek and holding it in retention/detention facilities. Detaining large amounts of flow has the potential to adversely affect in-stream habitat and wetland area. Meeting the Project Purpose This alternative meets the project purpose by reducing overbank flows. Practicability Assuming that upland areas could be found and purchased for construction of retention/detention facilities, this alternative would be practicable to construct; however, the stream and wetland impacts associated with diverting a large portion of May Creek through these facilities may be substantial and difficult to mitigate. In addition identifying locations, purchasing land, and constructing upland retention/detention facilities would exceed the available project budget and may result in greater impacts to critical areas than the recommended alternative. ., ··~ May Creek Alternativ ... a Analysis (NWS-2010-158) April 25, 201 I Page 5 Alternative 5 -Farm Management Description This alternative includes implementation of updated farm management plans and construction of farm pads. A farm pad is an area of fill placed in the wetland and/or floodplain that creates usable pasture in an area that is typically flooded. The farm pads would have culverts that allow movement of floodwaters through the fill material of the pad. Compensatory flood storage at the same elevation as the farm pads would be provided either on individual properties or collectively as a compensatory storage bank. Farm pads would provide reliable useable pasture space year-round for the property owners without removing sediment from the stream to reduce overbank flooding. Impacts While this alternative would eliminate the need for sediment removal and would maintain May Creek's existing connection to the 100-year floodplain, it would require the placement of fill in the 100-year floodplain and wetland (for construction of farm pads) and would potentially result in a loss of wetland area. This alternative would have more long-term adverse impact on wetlands than the recommended alternative, but would likely have less impact on in-stream habitat. Meeting the Project Purpose This alternative does not meet the purpose of reducing overbank flooding and increasing conveyance in May Creek. Instead this alternative eliminates the need to reduce overbank flooding and increase conveyance, by providing reliable useable pasture space year-round in another location. Practicablllty This alternative would require significant cooperation from the property owners. The end result would likely be less overall pasture area for each owner, but more pasture area that is useable year-round. It is not known if the property owners would agree to this scenario. Due to the large amount of fill that would need to be placed in the floodplain and wetland, this alternative would have similar permitting challenges to the recommended alternative. No-Action Alternative If the project is not constructed, May Creek will continue to fill in with sediment and reed canary grass, which will progressively decrease conveyance capacity and increase the duration of overbank flooding. The property owners will continue to lose pasture area as May Creek reclaims its natural floodplain. However, if the project is not constructed, existing in-stream fish habitat will not be altered, and existing willows will continue to provide cover to the stream in certain reaches where they will be pruned as part of the proposed project. If the project is not constructed, the benefits of the proposed mitigation will not be realized. Invasive reed canary grass will continue to choke the stream channel crowding out native May Creek Alternatives tltysis (NWS-20 I 0-158) April 25, 2011 Page6 riparian vegetation. In the Jong-term, the reed canary grass may also begin to impede fish passage. A buffer of native vegetation would not be planted and livestock would continue to have direct access to May Creek due to lack of fencing in all areas. In addition, Long Marsh Creek will remain in a ditch with minimal riparian cover. Conclusions Table I compares components of the five action alternatives plus the no-action alternative. Three of the action alternatives meet the project purpose (Alternatives I, 3, and 4). Two of the alternatives do not meet the project purpose (Alternatives 2 and 5); however, they do eliminate the need to construct a project that meets the purpose. All of the action alternatives result in either stream or wetland/floodplain impacts that would require compensatory mitigation, except for Alternative 2 which is a restoration project with positive benefits to critical areas. Two of the action alternatives require a significant amount of property acquisition (Alternatives 2 and 4) which also makes it difficult to fit the project into the budget. Alternative I is recommended because it meets the project purpose, permanently impacts only the stream (and not the wetland or floodplain), does not require property acquisition, and therefore fits into the project budget. T bl 1 C a e : omparson o f Alt ti erna ves Meets Permanent Permanent Permanent Requires Project Stream Wetland Floodplain Property Purpose? Impacts? Impacts? Impacts? Acquisition? Alternative 1 Yes Yes No No No (Recommended) Alternative 2 No' No No No Yes (Restore Floodplain) Alternative 3 Yes No Yes Yes No /Flood Berms) Alternative 4 Yes Yes Yes Yes Yes 1Stormwater Controls! Alternative 5 No' No Yes Yes No (Farm Manaaementl No-Action No No No No No • These alternatives do not meet the project purpose, but they eliminate the need to construct a project that meets the project purpose. References GeoEngineers. 2008. Final Draft May Creek Drainage and Restoration Plan. December 19, 2008. GeoEngineers, Inc. Redmond, Washington. Available at: http://www.kingcounty.gov/environment/watersheds/cedar-river-lake-wa/may- creek/drainage-restoration-plan.aspx Fits In Project Budaet? Yes No Yes No No Yes ..... ,( -, ... ,· Guarantee/Certificate SUBDIVISION Issued By: ~ Fidelity National Title' ~ Insurance Company Guarantee/Certificate Number: 611008780 I FIDELITY NATIONAL TITLE COMPANY OF WASHINGTON, 11'4:ijiy of Renton a corporation, herein called the Company Planning Division FEB 1 2 '1013 GUARANTEES King County, Department of Natural Resources and Parks herein called the Assured, against actual loss not exceeding the liability amount stated in Schedule A which the Assured shall sustain by reason of any incorrectness in the assurances set forth in Schedule A. . · LIABILITY EXCLUSIONS AND LIMITATIONS 1. No guarantee is given nor liability assumed with respect to the identity of any party named or referred to in Schedule A or with respect to the validity, legal effect or priority of any matter shown therein. 2. The Company's liability hereunder shall be limited to the amount of actual loss sustained by the Assured because of reliance upon the assurance herein set forth, but in no event shall the Company's liability exceed the liability amount set for in Schedule A. Please note carefully the liability exclusions and limitations and the specific assurances afforded by this guarantee. If you wish additional liability, or assurances other than as contained herein, please contact the Company for further information as to the availability and cost. Fidelity National Title Company of Washington, Inc. Dated: April 14, 2011 Countersigned By: Authorized Officer or Agent Subdivision Guarantee/Certificate SSCORP00817.doc/ Updated: 03.12.2010 By: Attest: President Secretary Printed: 04.20.,11 @ 11:27AM WA-FTMA-610051-611008780 • • FIDELITY NATIONAL TITLE COMPANY OF WASHINGTON, INC. GUARANTEE/CERTIFICATE NO.: 611008780 SCHEDULE A llabili):Y Premium Tax.· $0.00 $350.00 $33.25 Effective Date: April 14, 2011 at 12:00AM The assurances referred to on the face page are: That, according to those public records which, under the recording laws, impart constructive notice of matter relative to the following described property: For APN/Parcel ID(s): 803540 Tract A, STONEGATE, according to the Plat thereof recorded in Volume 177 of Plats, Pages 62 through 69, inclusive, records of King County, Washington. Situate in the County of King, State of Washington. ABBREVIATED LEGAL: Tract A, STONEGATE Title to said real property is vested in: Stonegate Homeowners Association, a Washington non-profit corporation subject to the matters shown below under Exceptions, which Exceptions are not necessarily shown in the order of their priority. Subdivision Guarantee/Certificate SSCORPD0838.doc I Updated: 03.12.2010 END OF SCHEDULE A Printed: 04.20.11 @11:27AM WA-FTMA-610051-611008780 • FIDELITY NATIONAL TITLE COMPANY OF WASHINGTON, INC. GUARANTEE/CERTIFICATE NO.: 611008780 SCHEDULE B 1. No search has been made as to the property taxes and assessments. Property taxes and assessments will be searched upon request. 2. Any interest of the individual owners of Lots 1 through 51 of said subdivision. Various instruments of record and the King County Tax rolls disclose the individual owners of said Lots have an undivided interest in Tract A. 3. Reservations and exceptions contained in the deed Granter: Recording No.: Northern Pacific Railroad Company 193931 Reserving and excepting from said Lands so much or such portions thereof as are or may be mineral lands or contain coal or iron, and also the use and the right and title to the use of such surface ground as may be necessary for ground operations and the right of access to such reserved and excepted mineral lands, including lands containing coal or iron, for the purpose of exploring, developing and working the land. The Company makes no representations about the present ownership of these reserved and excepted interests. 4. Easement(s) for the purpose(s) shown below and rights incidental thereto as set forth in a document: In favor of: Purpose: Recording Date: Recording No.: Affects: Puget Sound Power & Light Company Electric power line May 28, 1930 2607789 As described therein 5. Covenants, conditions, restrictions and easements but omitting any covenants or restrictions, if any, including but not limited to those based upon race, color, religion, sex, sexual orientation, familial status, marital status, disability, handicap, national origin, ancestry, or source of income, as set forth in applicable state or federal laws, except to the extent that said covenant or restriction is permitted by applicable law, as set forth in the document Recording Date: Recording No.: February 21, 1995 9502210643 6. Mitigation Agreement and the terms and conditions thereof: Recording Date: Recording No.: March 23, 1995 950323068 7. Right-Of-Entry for Survey and Sampling Purposes, and the terms and conditions thereof: Recording Date: Recording No.: February 5, 201 O 20100205000291 8. Restrictions, but omitting restrictions, if any, based upon race, color, religion, sex, sexual orientation, familial status, marital status, disability, handicap, national origin, ancestry, or source of income, as set forth in applicable state or federal laws, except to the extent that said restriction is permitted by applicable law, as shown on that certain map/plat of Stonegate. Subdivision Guarantee/Certmcate SSCORPD0855.doc / Updated: 03.10.2010 Printed: 04.20.11 @ 11 :22AM WA-FTMA.{110051-611008780 • FIDELITY NATIONAL TITLE COMPANY OF WASHINGTON, INC. • GUARANTEE/CERTIFICATE NO.: 611008780 SCHEDULE B (continued) 9. Rights of the public to make necessary slopes for cuts or fills upon the Land in the reasonable original grading of streets, avenues, alleys and roads, as disclosed in the Plat. 1 O. Any question that may arise due to shifting and changing in the course or boundaries of May Creek. 11. Any prohibition or limitation of use, occupancy or improvement of the Land resulting from the rights of the public or · riparian owners to use any portion which is now or was formerly covered by water. Subdivision Guarantee/Certificate SSCORP00855.doc I Updated: 03.12.2010 END OF SCHEDULE B Printed: 04.20.11 @ 11 :22AM WA-FTMA-610051-611008780 ' . .,J Cl O> ..... = = c ~ ..... = = ~ = = .... -. 111111111111111111 2001,62i0 029~ FIRST AflERICAN WD 8 00 PAGE 0et OF 002 88/21/2001 09 41 KING COUNTY, WA AFTER RECORDING MAIL TO: Namc_~S~to~n~e~g~a~t~e,__,,H~om~e~o~wn,.,,,e~r~s-A~s~s~o~c~i~a~t~i~o~n-- Eif8J245~ij Addres$,.,_P_O_B_o_x_2_69_1 ___ ~------- Cny /State __ R_e_n_t_o_n_, _W_A __ 9_B_05_6 _____ _ 0B/21/ZIIGI 09:41 KING COUNTY, WA TAX $2 00 SALE $0.ee PAGE 001 OF 001 Statutory Warranty Deed THE GRANTOR CHAFFEY CORPORATION, a Washington corporation First Ameru:an Title Insurance Company for and 1n cons1deratton of One Dollar ($1. 00) and other valuable consideration pursuant to plat . dedication m hand patd,conveys and warrants lo STONl!GA:EE,.HOMEOWNERS ASSOCIATION, a Washington non-profit corpor-.__<•_h,_,,_pa_c_,fi_.,._,_"1_,_co_m_pa_•Y_u_u_o_m_n _ _; ation the followmg described real estate. Sltuated m the County of KING • State of Washmgton TRACTS A, C, F, J and H, Plat of Stom~gate, as per plat recorded 1n Volume 177 of Plats, pages 62-69, records of King County, Washington. Assessor's Property Tax Parcel/Account Number(s) vn~1-:05 @ ,.-OURTESY RECORDING ONLY NO UAlllUTY FOB. VALIDITY ANO/OR ACClJRAG.Y ASSUMED BY FIRST AMERICAN mu; INSURANCE COMPANY Tracts Tract Dated A, F and J are undivided interest -no tax C -803540 0550 06; T.ract H:803540 0480 02 acct no's JDNE 15 ,*9< 2001 LPB·lO (11/96) • STATEOFWASHINGTON, } ss County of • ACKNOWLEDGMENT • lnd1Vldual On tlu, day pen,.onnlly appeared before me--------------------------- --------------------------------------10 me known 10 be the md1v1duAI(~) de,c11bed in .and who execuled lhe w11hmand foregoing mslrument, ,md dcknowledged 1hat ______ _ i.1gncd 1hc snme d'> --------free ,md volunlary .i.ct and deed, for chc uws and purposes therem men11oned GIVEN under my h<1.nd Md offlc1<1.I se.tl th1\ ______ d.11y of _______________ , 19 __ Notary Public ,n tmd/or th~ State o/Wa~/ungton, 1e11d,ng at My appointment expire,--------------- ACKNOWLEDGMENT· Corporate STATEOFWASHINGTON, } ss County of J . On this Q day of ... )..A..A.(Yvl..-~ , before me, the undersigned, a Notary Public m and for the Slate of Washmgton, duly comm1SS1:ed and sworn, pcrsonnJly appeared ~ StJuv4 V f ~s,dcnt and :ma" to me known to be the Sc,i;i:tisy, HSfUtw•l-J, or __ ,._[~A'ltlcue=(L~-'-"-'--1'1-__,,Uif=.__'-E.,_ __ • __ _ the corpo1al1on that executed the foregoing mslrument, and acknowlcd,gcd the <Mid nulrnmcnl to be the free and volumary :: deed of smd corporation, for lhe uses and purpo\es therein mentioned, and on oath 'ltated 1hc1t 9't,e i J nuthom:cd to execute 1hc said in~trumcnt and thnt the .seal affixed (1f any) IS the corporate "Seal of '1a1d corporation TinsJurat 1s page ___ of ___ and 1s attached to ____________ dated---------- V ./ 193929 Deed Filed Jul:r s1,1900,10:'51 ""· Dated llay 25,1900 e.on,$16 Titusville Lode• llo 34 I O O F of l(•nt,,W i'o Jos il Berto of K ,o,~I ~ F p does hereby g b s c lo c unto s p all of lot 4 bllt 9 of Tho Kent b CeI!let.t:1ry accde; to rec plat. #s =--=c -·------= ---·-----== ~=======~===~=== 1939~0--N ,(l, ,/ Deed Filed ,ul;· ;;1;1900111::\fi ru,, V0 ;;-J7 D ,J.-I l9S9Sl ,·.:c·.;1! Dated uay 19,1891 C.011,,;151,,;4 (Form R rd 490 with !!!in res) North~rn Pacific Railroad Compnny p f p Central Trnst Comp of H Y trusttJa, p t p To r.rarcel Fourn11:1r of Hew / / . / Cas tl e, K Co, W J,i'/v / The 1'raot.l Jill t ofAsec 3 tp :,:; H B 5 RV! con'·G 35.92 ac---sinc< 2nd May BS--·· 2wit.s (Corpoenl) I, Nor',hern rucifi Ry Ja1. Att.s t: Geo n F. Railroad Company s H Williams, Vi a e 1, Stt,~1·ttt.ary Ct:n tral Trust C npany of lie,, Ycirk, Trustee By G , t:rC1an,VPresident At teat: C H P B coc,k,Secret.ary s 01' N Y Cty .lo C.o or 1l Y)ss. July '?.I ,1661 by J !l W e.s v p of sd Com1,r of D in"i!Y for. tJ1 a s of w. Att " And July 31, 1881 t,y O S as v p of wi t,h seal. -- •==-=-:.:---=--------·-=----- Mtge .Filed ,Tuly Sl,1900,12:;;o pm, Dated .ruly :;o, 1900 Con.$~20 lrd co bof t,h seal, sd ~rust co LR Kidder bef Sl!I co~mrnr ~~ .A/ • R I ' . ' 121==----""'·· ----==s=7= al. 1.rt lltge /ft> 193932 John Bl aclt e.nd ~~ Ann Black SATlSFAc'r,o;., • OVER 1 ,1_,( 6 or s, w To . · F p do horeby 6 b s c l'c c un tn s p and -·1and in K co,/W, to.Id t: ! . '· Lot 14"bllt ?"or Bradner•s A<ld to .;,-sirig the tens &c. •. To ·sec $?.?.O, int 71,, n e d, A f ~50, 2 wits John S of w Oo or K)ss, July 30,1900 by J · seott N P 1n and J'or .1oan Band Gene AB hi ·he S of' W res at Sat or l!tga Filed July 31,1900,1:50 na ted ,rul y 13, 1900 Paul Lue be 01' S, \V and a the flg of s. Tog '01th all and (Seal). (Seal) ,rt' ( sep e xai,) bef Ro swell • Com ex Heh 2 11 1902 .. ., VoVl,1 ).!tge }' / 19::;9:;:, I }:.',·.· ... ~, . ',· 'l . ·1 1 ., .. tou1sa Ha_ll Russell To F..l.hridze "8 p does h ere'by cttr t and flea that a a - and e,t by a p to !I W HiSBins to sec ~;; . ./ dulr assgn~,ae sho<Yll on p 6 Bk 145 of· y by sd L A R asgnd to r p aa shown on p ding and vf m4 5e ex Oot 11,1898 md '°/~•Y l and int and by sd !I w !I tte;•s to touisa A l!al.l !!lld 257 Bk 158 01' !ttg&s, ec,verg,,_·, r tho r:t prop ,,;1oo•wiY: ,/ r Lots 3 and 4 blk 22 or Clilman•s Add to ~-he C ot s, ~ rec in the aud otr 01' K co, V' in Vol 9 or ltte;os l' 566, tog '11th , ·the dabt thereby sao is pd d ischd e.nd at ln full. • -••· · Lou sa Hall Russell (S6a.l) ' ' i D ]'.id May 20 1930 t-30 Mar 24 1930 •1000 G W Upper and Emme L Upper, h wt 11 , to Lonnis A llnrth and Lil Ian R Da fp oy and war to ap the tole; re aot the north 150 ft of eo 2.5 sores ot no all t Int pert of the Eg or the N"'z ~ bet oo roads on the weot s1da end nort Highway less so 10 sores th~f, the no with the ,r:, line, •ll in seo 33, twp 2 subj to 111tg for HOO due .ran _ l purohr assumes andag,rees to pay ow Upper al 2S0778' j·' /</5,~ h hwf -;, 6 '7 ,· <· I th 5 aoree or the folg tt; nd of tbemi:t or SEt l!lyl.ng and south ends aod State ine oted lOoorea to be pll nr-lewm 33, at 8% int, woh the E111meL Upper s kaw on ·Mar 24 1930 by G w Upper and E a L Uppsr, h"1', 1,er RH White n p for wn res at s n sJul 1933 111811 op 423 Lat no D Fldl\137 ::a 1930 1-40 Apr 27 1930 •10 and o v o Iaaao Bsroh and .3arab.Harob b:wr, of a, to Antonetti Pizzella and Nick P1 fp 07 andwar to s · ch<ll folg reeet 1n tllat pvrtn or lot 11 blk l plet a<lo !g to plat reodd in Tol 2 of plsts com at th a interseotio·n or the no mer east margin or 23d ave so as now laid th no al sd east i;,ergin or 23d ave so bsg; th so ~9 deg %6'30" east 100 tt: of 23d ave so 47.86 ft m or l to thane al tha no ll otsd lot ll 100 rt to tbe al the east margin or 23d ave so 46.9 This oyenoe 10 111d subj to mtg in Iseao Baroh encl llsrall Berob b'1f, to th Bank Seattle, Wash t1ite to mark .Tobn P Galla gilelt M Genest Issac Barob . Sarah .i. Baro her mark KOO on &pr1l 27 1930 by Isaao Baroh an bet John P Gallagbnr a p for wn ree at fld by sp 120 23d eo hh. 2607788 /'({;ff ----11j I )_ .. . --. / Jeoksonst aGd to tbe aa 24 reoa of od oo d t; n or Vain st "1th tllo ut and eatab by the oe, 02,7& ft to the true pt oi: h no oll to ad east marg1a cor otsd lot ll; tb va"t n'lloor ofsd lot 111 t~ BO rt m or l. to :.~ ·. • 'leg Ill! sum of <t30r,r. md by Washington :.Utuel .sevil!gs Sarah 1t1ro1Jr bvf, s n sl,'.el:' 3 11138 I({ 7:,-- "a eement tlc!May 28 1930 1-43 ,, -· May 20 19:50 91 = ,P ) Pauline Mcllo111n fml)' PeulinQPeterson a widow, to Puget s 0 un4 Power "'Ligllt 0 0 mps a Maas 00,P __ ... I --am sa 2462404 -·-angl Una of pdll a -- NE! , be~ oteeo 3 top 83 n r 5 " ~eg at a pt 460 f't east ot .the aw or sec 3 twp 23 n r 11 ,. " m; rg t ll wes meo a dist ot 480 ft to ad nw oor ut t 31 th due so ana pll 111th t!.o east bd 536 rt; tll duo oaat and pll olth tile n or 330 tt; th nsly to the ,,t or 'Jag o the aclootar lino o ad trsnsm1sa!a ba 100 aa role; .. beg at the se oor at'sd NEt of th deg 18' east 533 rt; th an an angle o. rt m or l to tna cent 111Srgin of oo roe beg; th oontinuing oa aame be~rlng 100 . or a·,ova dee p 1;y to~etll <11th the right at all time Paulina llo'-'o kon on M11y 20 1930 by Pau 1ne r.:oUouJ,n "Rido'ff, bef JSdward P Thwinf!;, n l' for wn m less partn d r; oor or the ~Et or t bo ,~ti al the no b dey 11 of ell eliEt or tneHEt of ad ""@ l1 ofad sec, adt st or bdry l1 o fsd sea, a 41 st 4.92 acres et1d less roed ~nd d!et:rtbuttoo l1 to Nllt ot seo 1J; tb a.o O 67 dog 36' to the latt !~ wob is the true pt of rt m or l to tbe """t li --srn a a torn tlb Du.gs n rmly Pauline PatersoD ~ res et s n iaFeb ::I'-l93l ·• ·- e CITY OF RENTON WI lEN RECOR.OED REllJRN 10: COVENANT i'ER 1 5 1995 Ollln! ul tho <ltytlcrk Rtn,on Munlclp,d llulldlng 2DO ~hll l\v11nueSoulh lli:nlun, \'JI\ 911tl5S This covenant is matle on the ~ day of l"li!lic1'/ED ~~ • ~11TY CLERK'S OFFICE 1995, by the owner(s) of property situated in King County, Washington, known as the stoneg•te subdivision and legally desc~ibed as follows: I RECEJVEO FEB 17 j995 KING COUNTY SEE EHllrBIT A I For and in consitleration of annexation to the city o1,...:.R:.::E,:CO:::,:R~D:!;.EA~~J Ron~on, and other good and valuable consideration, the sufficiency of which is hereby acknowledgetl by the covenantee, the covenanter hereby agrees and.covenants as follows: 1. 'l'he development of the stonegate subdivision will be limited to no more than 53 lots or single family homes and the lots shall not be further subdivided. This covenant shall be perpetual in duration. All the conditions of this covenant shall run with the land, and shall be binding on the successors, aoaigns, personal representatives and heirs of the covenanter, including but not limited to all eUbeequent owners of the subject property. -1- S-21680].1 111)'6 r ;/ .. (: .. -- ·- STATE OF WASHINGTON SBo COUIITll OF KING on this day personally appeared before me Donald H. Leavitt, to me known to be the President of stonegate Limited, the corporation that executed the foregoing instrument, and acknowledged the said instrument to be the free and voluntary act and deed of said corporation, for the uses and purposes therein mentioned, and on oath stated that he was authorized to execute the same instrument. ...:j,.A?, GIVEN under my hand ,-«./Ldfj, , 1995. 1•216803, 1 and of!ioial seal .this~ day of ~-~ ,·'i -:,,;,c /avu--d.:t:z=.zt~v~. C,c2,0s fltbttlGtl:J''I-) Notary Public in and for the State of Washington, residing a~/7}/JAJ!,~. Hy commission expires: -.oZ,. . ' ... •• • · .• 1 0 EXHIBIT A Legal Description: That portion of the southeast quarter of the northeast quarter of Section 3, Township 23 North, Range S East, Wtllameue Meridillll., lyin8 west of the west line ofth• Plot of May Valley Co-op Community Addition, according to the plat thereofreoorded in Volume 66 of Plats, page 93, records of King County, Washington and the northerly e><lension of said west line; TOGETHER WITH !hot portion of Government Lot 1, Section 3, Township 23 North, Range S Eas~ W. M., described as follows: Conunencing at the northeast comer of said subdivision; Thence North 88°37'17' West along the north line of said subdivision 30 feet to the Point of Beginningj Thence continuing North 88°37'17' West, along said north lino, S94.68 fee4 more or Jes~ to a point which is 698 feet from the northwest comer of said Government Lot; Thence South I7'02'S2.'WOS4 5S6.69fee~ more or less, lo a point which is S36 feet south of the north line of said Govenunent Lot and S48 feet east of the west line of said Government Lot; Thence South 0l '2S'07'West pmllel with said west line of said Government Lo~ 595.79 feet, more or less, to the south tine of said Govcnunent Lot; Thence South 88'01'27'f.ast along said south line, 744.61 feet, more or less, to a point 30 feet from the southeest comer of said Government Lot and the west margin of 148th Avenue Southeast; Thence north along said margin, 30.00 feet; Thence North 88°01'27' West425.00feet; Thence North 01°25'22.' East 262.33 feet; Thence North 65°00'00' East 113.89 feet; Thence South 88°0l'27"Eest 323.00 feet to said west road margin, and a point from which the True Point orBcginning bea,s North 01°25'22" East; Thence North 01°25'22" East, pmllel with the east line of said Government Lot Md along the west margin of said 148th Avenue Southeast, 73S.5S fee~ more or less, to the Point of Beginning. Adjoining tho existing City limits ofRenton as annexed by Ordinoncc #3972 along tho west quorter section line of the southeast quarter of the northeast quarter ofSeetion 3 from the southwest comer of said subdivision to the south lino of the north half of the north half of the southwest quarter of the northeast quarter of said Section 3. -~~~,-~.~ • "'"1 \.L~' "'', ,, ".._• • , "· • 1. ' I t • ., .. .. H After recording return 12: Issaquah School District No. 411 S6S N.W. Holly Slrcet Js54quah, Wa.hington 98027-2899 Ann: Doug Snyder MffiGATION AGREEMENT • THIS MITIGATION AGREEMENT {"Agreement") is made this /f~~ay of March, 199S, between the ISSAQUAH SCHOOL DISTRICT NO. 411, Issaquah, Washington {lhe "District") and STONEGATE L!MJTED {the "Develope('). RECITALS A. The Developer has submitted an application to l(jng County for the construction of 52 new single family dwelling unir:1, commonly known as the Proposed Plat of Stonegate, File No. S90P0068 (the ·~ojeet"), more particularly described on Exhibil A. attached hereto nnd incorporated herein by reler~ce. The developer has requested that this: Project be annexed to the City of Renton. B. The State Environmental Policy Act, Chapter 43.2IC RCW {"SEPA"), provides processes and procedures whereby major actions by slate and local agencies, including, but not limited to, plat or PUD approval or lhe issuance of building permits, may be reviewed to detennine the nature and extent of their impact on ·the environment Impacts on public services, including schools, arc environmental impacts for the purposes oF SEPA. SEPA requires the mitigation of adverse environmental impacts. C. This Project is anticipated lo generate 20 elementary school studenls and seven middle school student~ and these students will be served ~y Apollo Elementary School and Maywood Middle School. The Disirict's student population and growth projections indicate that both of these schools arc currently operating over capacity, and that the Project will have a direct impact on Apollo Elem~tary School and Maywood Middle School. D. RCW 82.02.020 authorizes the 1 District to enter into a voluntary agreement with the Developer for payment to mitigate the impact of the Developer's Project. E. It is the policy of the District to recommend that the direct impact of development be voluntari~y mitigated by the p:iyment of fees and other mi.ligation measures where appropriate. F. Th: Developer has agreed to mitigate, on a voluntuy basis, the adverse impact of the Project on the District. ( I I l l ·1::. ·., ( r 0 AGREEMENT NOW, THEREFORE, in consideration of the above recitals amJ the mutual promises and covenants below, the District and the Developer agree a.s follows: I. The Developer acknowledges and agrees that there is a direct impact on the District as a result of the Developer's Project and tlint this Agreement is necessary as a rcsuh of that impact. 2. The Developer acknowledge, tlfld agrees that in order to mitisatc the dire~t impact or the Project, the Developer has offered to pay the District the following sum or money: Two Thousand Three Hundred and No/JOO Dollars ($2,300.00) for each single family dwelling unit (the "Mitigotinn Payment') or the total sum of One·Hundred Nineteen Thousand Six Hundred and No/JOO Dollars ($119,600.00) for tho 52 new single family dwelling units. 3. Any extension, renewal, modification or amendment to the Project that results in ~ .in adjustment in the number or dwelling units shall rtsult in a corresponding pro rn1a adjustmcn1 './J in the total M1ount of the Payment. 0 '"' N 4. The Developer agrees that the Mitigation Payment (in the amount of Two g Thousand Three Hundred and No/100 Dollars ($2,300.00) per dwelling unit) shall be paid to tho :n District at the time the building permit for each dwelling unit in the Project is issued. ~ 5. The Developer agrees to place a covenant on the face of-the recorded plat, and include in the deed for each affected Jot within the plat, that the amount of Two Thousand Three Hundred and No/100 Dollars ($2,300.00) shall be paid to the District at the time 1he building pcnnit for each dwelling unit in the Project is issued. 6. · The Developer acknowledges and agree., that the Mitigation Payment is authorized to be used for capital improvement, to the following facilities: Apollo Elementary School, Maywood Middle School, and/or any other facilities that may be affected by the Project and/or the purchase of portable facilities. 7. The Developer agrees that the District hu five (SJ years from the pa)'I'lent date to spend the Mitigation Piyrncnt for the capital improvements described in paragraph 6. In the event that the Mitigation Payment is not C)'(pended within those five years, the moneys wm be refunded with interest at the rate applied to judgments to the propmy owner, of record at the time of refund; however, irthc Mitigation Payment is not expended within five years due to delay which is attributable to the Developer, the Payment shall be refunded without interest. 8. The Developer shall record this Agreement. 9. Th..: Developer waives and relinquishes its right to protest or challenge the payment of the Mitigation Payment puCSU!lnl to ihls Agreement and hereby covenants and undertakes that it forever rerrain'i and desists from tnstituling, asserting, filing or bringing any -2- fun • '1·1 5 " 0 --r-•··--~ ilt't, C ·. • i l ! = 0 lawsuit, litigation, claim, or challenge or proceeding to challenge this Ajir .. ment, claim any repayment or reimbuncment o(funds. performance or improvemenu provided for therein. or any oriu temu and condilion.,, on any ground or buis whatsoever. 10. The District hmby waives any objection to the Project u presently proposed. 11. Tho District and the Developer asrcc that the Mitigation Payment will be full and complete mitigation for the impact of1hc Project as preseruly proposed on the District. 12. This Agree,nent shall be binding upon nnd inure to the benefit of the heirs, executors, administrators, successors, and assigns of both of tho Developer and the District. 13. !fan action must be brought to enforce the terms of this Agreement, such action shall be brought in King County Superior Court. The prevlliling party shall be entitled to payment of its cos11 and rtl!IOnablc attorneys' fees, 14. This Agreement constitutes the entire agreement between the parties end any other agreement either written or oral allall be null and void. DATED: _;5'.1...,/uJ,,.,_,1/,_l/c:,J ___ _ -3- ISSAQUAH SCHOOL DISTRICT NO. 411 ·1· -Ii~ //4/t(({,1,-,~ · w11-i/ By: William H. Stewart, Superintendent .·;...·~. .. V' • : ' r I -d = STATE OF WASHINGTON COUNTY OF KING 0 I ccnify that I know or have satisfactory evidence that William H. Stewart is the person who appeared before me, and sai.d person acknowledged that he signed this instrument, on oath stated that he was authorized to cxecurc the instrument and acknowledged it AS the Superintendent of Issaquah School District No. 411 to be the free and voluntory act of such pnrty for the uses and purposes mentioned in the instrument. Dated: 3/a1/9~ NOTAAVPU9t.lC STATE OF WASH!NCTON DEBRA I( S0U1HAROS 1.tfAi>PolnTmonlf.q,iresMAQ t.109!1 STATE OF WASHINGTON COUNTY OF KING Title My appointment expires 3 .1.q'j{ I ce,1ify that I know or have satisfactory evidence that Donald H. Leavilt is the person who appeared before me, and said per!lon acknowledged that he si8(1cd this instrument, on o~th slated that he was authorized lo execute the instrumonl and acknowledged ii as the President of Stoncgate Limited to be the free and voluntary act of such party for the uses and purpos,s menlioned in the instrument. Dated: 4¥4' / (.__/Jff' ,·r:~"""'~'. ~" ,_:!~ ' " ..... s:. ,,,,,; ' "Ui -4. Title · > rl ). }..,,,.. My appointment expires~ 1 \ i ' ' ! .: :,< .. . £ r . I (!) EXHIBIT A LEGAL DESCRIPTION • THAT PORTION OF THE SOUTHEAST QUARTER OF TIIE NORTHEAST QUARTER OF SECTION 3, TOWNSHIP 23 NORTH, RANGE 5 EAST, WI!.LAMETIE MERIDIAN, LYING WEST OF THE WEST LINE OF TilE PLAT OF MAY VALLEY CO-OP COi\11.fUNJTY ADDITION. RECORDED IN VOLUME 66 OF PLATS, PAGE 93, RECORDS OF KING COUNTY, WASHINGTON AND THE NORTHERLY EXTENSION OF SAID WEST LINE. TOGETIIER WITH THAT PORTION OF <"JOVERNMENT LOT I, SECTION J, TOWNSHIP23 NORTH RANGE S EAST, W.M., BEING MORE PART!CULMLY DESCRIBE!) AS FOLLOWS: . COMMENCING AT TIIE NORTHEAST CORNER OF SAII> SUBDIVISION; THENCE NORrn 8&'37'17" WEST ALONG THE NORTH LINE OF SAID SUBDIVISION 30 FEET TO rnE POINT OF BEGINNING; THENCE CONTINUING NORTH 88'37'17" WEST, ALONG SAID NORTH LINE, 594.68 FEET,· MORE OR Ll!SS, TO A POINT WHICH JS 698 Fl!ET FROM THE NORTHWEST CORNER OF SAID GOVERNMENT LOT; THENCE SOUTH J 7"02'52" WEST 556.69 Fl!ET, MORE OR LESS, TO A POINT WHICH JS S36 Fl!ET SOUTH OF THE NORTH LINE OF SAID GOVERNMENT LOT AND S4S FEET EAST OF TIIE WEST LINE OF SAID GOVERNMENT LOT; THENCE SOUTII 01'2S'07" WEST; PARALLEL WITH SAID WEST LINE OF SAJD GOVERNMENT LOT 595, 79 FEET, MORE OR LESS, TO THE SOUTH LINE OF SAJD GOVERNMENT LOT; THENCE SOUTH 88'01'27' EAST, ALONG SAID SOUTH LINE 744.61 FEET, MORE OR LESS, TO A POINT 30 FEET FROM THE SOUTIJEAST CORNER OF SAJD GOVERNMENT LOT AND THE WEST MARGIN OF 148TII A VENUE SOUTHEAST; THENCE NORTH 01'25'22" EAST ALONG SAID MARGIN, 30.00 FEET; THENCE NORTH 88'01'27" WEST425.00 FEET; THENCE NORTII 01'25'22" EAST 262.13 FEET; THENCE NORTH 65-00'00" EAST 113.89 FEET; TIIENCE SOUTH 88'01'27' EAST 323.00 FEET TO SAJD WEST ROAD MARGIN, AND A POINT FROM WHICH THE POINT OF BEGINNING BEARS NORTH 01'2S'22' EAST; THENCE NORTH 01'25'22" EAST, PARALLEL Willi rnE EAST LINE OF SAJD GOVERNMENT LOT AND ALONG THE WEST MARGIN OF SAID 148TH AVENUE SOUTHEAST, 735.55 FEET, MORE OR LESS, TO THE POINT OF BEG!NNING "o~ Recording Requested By And When Recorded Mail To: King County Water and Lands Resources Division Open Space Acquisitions Unit 201 South Jackson Street, Suite 600 Seattle, WA 98104 1111111111111111 20100205000291 DNIIP "ISC a~ PIIG£-ee1 OF 013 .~ e2,0,12e1e 10:42 KING COUNTV, LIA RIGHT-OF-ENTRY FOR SURVEY AND SAMPLING PURPOSES 20100206000291.001 Grantor [Seller]: Stonegate Homeowners' Association, a Washington non-profit corporation. Grantee[Buyer]: King County, a political subdivision of the State of Washington. Legal Description (abbreviated): Tract A, Stonegate, Vol. 177, pgs. 62-68 Additional legal(s) on Page 2. Assessor's Tax Parcel ID#: N/A. Project [Area]: May Creek Sediment Removal. Parcel[#]: Stonegate. The undersigned, Stonegate Homeowners' Association, a Washington non-profit corporation, hereinafter called the "Owner'', in consideration of mutual benefits and other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, hereby grant and convey lo King County, a political subdivision of the State of Washington, hereinafter called the "County," a permit or right-of-entry upon the following . terms and conditions: I. The Owner hereby grants to the County an irrevocable right to enter upon the lands hereinafter described at any time within a period of twelve (12) months from the date of this instrument, in order to complete a siream survey and take soil samples. 2. This permit includes the right to ingress and egress on other lands of the Owner not described below, provided that such ingress and egress is necessary and not otherwise conveniently available to the County. J. All tools, equipment, buildings, improvements, and other property taken upon or placed upon the land by the County shall remain the property of the County and may be removed by the County at any time within a reasonable period after the expiration of this permit or right- of-entry. mayer scdimrnt·stomiga1e Pagel of.1 Novnnbe, W, 2CHl9 • 20100206000291 .002 4. . The county shall have the .right to enter upon the lands hereinafter described during the period of this permit or right-of-entry. 5. It is understood and agreed that if the County does not acquire title or other necessary interest in said land prior to the expiration of this permit or right-of-entry, or any renewal thereof, the County agrees to be responsible for any damage arising from the activity of the County or its agents on said lands, in 'the exercise of rights under this pennit or right-of- entry, and shall repair such damages, or, in lieu thereof and at the option of the County, shall make a cash settlement with the Owner. The land affected by this permit or right-of-entry is located in the County of King, State of Washinb>ton, and is described as follows: Tract A ofStonegate, according to the plat thereof recorded in Volume 177 of Plats at pages 62 through 68, inclusive, records of King County, Washington. 1 0.. IN WITNESS ~OF, the said Owner has hereunto signed his name this --~u ___ day of ~ , 2009. OWNER: Stonegate Homeowners· Association, a Washington non-profit corporation ma~r scdimcn I-stone gate PagelofJ Nuvemhcr 20, 200'.J / , 20100206000291.003 STATE OF WASHINGTON, I fSS. County of King. I I hereby certify that I know or have satisfactory evidence that i~ ~n « _________ isl-the person(s) who appeared l:iefore me, an~) acknowledged that _he_ signed this instrument, o oaths ted that he_ is/are authorized to execute the instrument and acknowledged it as th tonegate Homcowner's Association to be the free and volu t y r the uses and purposes mentioned in this instrument. Dated: /o?-1£1-CJ 'J Printed signature Notary Public in and for the State of Washington, residing at __ 4-"""""''=~,e"""'ti==~=e!------ ,.g-e, O -/~ My appointment expires ____ ,.L----- Page J of J · Novtrnbcr 20. 2009 ~ CC> !,! 0 J, t-: t-3 ... • '-':.,,,,, ·~, .•. "' "' STONIEGATIE ,,, ... :· ., .... ,. WA-96-043-FP LNtl-10-0304 f PORTIO,N--GOV'T LOT ,,sl" .:· .... ·=:. AND THE S.E. 1 / 4, COUNTY OF 1 RENTON, TWP.23N., RGE.SE., OF WASHINGTON N.E.1 / 4, SEC.3, KING, STATE W.M. _,,-·,CITY OF No>. W57 (l'll.O 11P/ll} II 19t,,e&6$J~ (.r) Sn;t<(l;I.Tt =--· M O,int.5~1,. (1'1'l .. ,·····' 5CM.[ : 1• • :ioo' "' SCALE lN rn;r MtMMNI: K.i:.,.,s. •= . _...,. ,,,,··F·.:.:.:..:_.~--, .. ,.:,~i:,r:in'"'~ J, ,, I..,· ·'m/I<,," '~ '! ~.ru:,;'. mT"T·r.~ " ' + ~~A-:':f"'t1 .. •J . ·<tRACT A -~.:: ·("'"\~~~o},,-., • J 1 ; ~,= 3 I\\ ::. SHEE'f., ... ,.. ,, ~ < ."' [,, ••• ,,_,.;· • ,J sET ~ ,.RtlMI • ::::! GOVT LOT 2 ;,.,,. ' '. ·:-.3 Of' 7 I .,1 / ~· .,,.. ,., c _._;-ANO flP HO.t.-11m .. ,;:: !::•::! , , ··_, • '.,,,•'' ' ~~,. f ~; •:-· ... -F" 2: a -';!f \ ZIJJ: ,:JJ, t.l ~' 1 <' :-~ IIOlJN:;.lRY COl!NOIS Fl:JUN!I ~F; ! ', ( 1· • 100·) ,i-....... , • i /:" F'£1f,R£CORO OF $URV£Y ~ , • :, \ ,, :I ' '": ,,,· ltJ,ficloK !03 Of' SIJ~, PM! 1'8, H "P!.~O W \ ! . 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"'lii?. . ~,: --.. ·E ..... --·· . -,~,..i~ ~: ~: _ : ~: ,,,,, r. ,,: '~ ' ~ . ~ oJJ>Jn_____J 5 ~ :, I/ORTON DENNIS l ASSOCIATES, IN ... l!IDffi CON$Uln:IG ENGIIIIWI J.20 Second A .... Soult> l{orklcml, 'll'A iaOOJ-H!J.7 -~ 822=--'2,525 King County File No. S90P0068 " 2f.11\.04ft. = ~~ ,. ~ 27 --1 f 8 ii~ ~ ... ~\ ... -,~. 20 11.112. ... 11. (]ID }lz.1. SEE N.E.1 / 4, SEC,3, KING, STATE TWP.23N., RGE.SE., OF WASHINGTON W.M. ~k~ r:T "'1QI (llPJ ( (/,~~'c'<a'.', ~~ 52 !,-~ SHEET 5 i· Ill " .~ ¢ii ~w ~~- •'\• °l\! · 1.:-' 22 14,IQ. "i" ft. = ... ' "-· .. •. ~;;~· ' ~, , .. ~. ..,,~ ',,.... , ,;/',,~4~~~~. ~ ·.. . 's,, '-~..... ' . ' ', ''<.,. <::, ~· ... ;;'.:,>,,)'.' i5 "'"''' ;~: .. ~ ',, ··0·~ (" ",~ ~,,,.~,;· .. ,,.~. ~-"t,t..", ' ~ ---.....~. \ I .,. _,;: "<'--.::ij.~ ' ·• ' \ -~... ~ '"<• ·, >;\ ( ·., •• ,.. n. ... \ \ ,,.om.... !, "'-, \ "'\ ' : ',,' --,~um) -.:, . I \ .,; • -~t \ J!i ·~<:c/. i .. ·······..., ..... v\ \,~\··,f' ...._(;) '6. 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(/) .i,. _,. ~ (/) ..., ..., n o· ..,, ·"' ~ -;g (/) ,, ::i::. _N z "' G) z _,; 0 z :u G) ~ lJ1 ~ RECEIPT EG00004355 BILLING CONTACT Doug Chin King County Water & Land Resources Division 201 S Jackson St , Suite 600 Seattle, WA 98104 REFERENCE NUMBER FEE NAME LUA 13-000187 PLAN -Grade and Fill Permit PLAN -Variance Technology Fee Printed On: February 12, 2013 Prepared By: Gerald Wasser ;:::::1 Pi City of11 --=====--= . j L/ &JJ1j1g@)]l TRANSACTION TYPE Fee Payment Fee Payment Fee Payment PAYMENT METHOD Credit Card Credit Card Credit Card SUBTOTAL TOTAL AMOUNT PAID $2,000.00 $1,200.00 $36.00 $3,236.00 $3,236.00 City of Renton Planning Division FEB 1 2 2013 Page 1 of 1 I I I I I I I I I I I I I I I I I I I Final Adopted rMu!W CC~~~~ IBs!§~ ~ !CC¥~@~ [Pl!~ 0, 0 -- City of Renton Planning Division FEB 191013 --.... ..--.;.~_ ....... ..:··_ -~"_,_,.-~· ' ' ' April 2001 .. " ._ ........ -.,. .:. ,. __ - , .. - @ KING COUNTY I I I I I I I I I I I I I I I I I I I Acknowledgments John Affholter, a May Creek Citizens Advisory Committee (CAC) member and long-time May Valley resident and citizen activist, passed away during preparation of this plan. The participants in the development of this plan would like to acknowledge Mr. Affholter's commitment to the Valley and local residents, as embodied by the spirit and cooperation of all the CAC members. The development of the May Creek Basin Action Plan benefited greatly from the contributions of the CAC members. These dedicated volunteers participated throughout the planning process and provided guidance and direction on many of the plan's recommendations. The authors of the May Creek Basin Action Plan also would like to acknowledge the contributions of Rick Rutz, who managed this project through the completion of the Current and Future Conditions Report and the early stages of the solutions analysis. Rick's hard work was instrumental in developing a comprehensive set of priorities for actions intended to improve surface-water conditions in the May Creek basin. I I I I I I I I I I I I I I I I I I I I TABLE OF CONTENTS Page LIST OF PART! CIP ANTS ......................................................................................................... iii 1. EXECUTIVE SUMMARY ........................................................................................... 1-1 1.1 Overall Plan Goals ............................................................................................... 1-1 1.2 Basin Overview .................................................................................................... 1-1 1.3 Compliance with Federal Resource Protection Laws .......................................... 1-1 I .4 The Plan ............................................................................................................... 1-2 2. INTRODUCTION .......................................................................................................... 2-1 2.1 About This Plan ................................................................................................... 2-1 2.2 Funding Sources Available For Implementation ................................................. 2-2 2.3 The May Creek Basin ........................................................................................... 2-4 2.4 Conditions Within The Basin .............................................................................. 2-7 2.5 Potential Solutions ............................................................................................. 2-10 2.6 Agencies With Roles In May Creek Basin Resource Management. .................. 2-11 3. RECOMMENDATIONS ............................................................................................... 3-1 4. 3. I Summary Of Primary Recommendations ............................................................ 3-1 3 .2 Detailed Primary Recommendations ................................................................... 3-5 3 .2.1 Basinwide Recommendations .................................................................. 3-5 3 .2.2 May Valley Subarea ............................................................................... 3-15 3. 2 .3 Lower Bas in S ubarea ............................................................................. 3-21 3.2.4 East Renton Plateau and Highlands Subareas ........................................ 3-27 3.2.5 May Valley and Highlands Subareas ..................................................... 3-28 3 . 3 Secondary Recommendations ............................................................................ 3-3 I MANAGEMENT PROGRAM EXPECT A TIO NS ..................................................... 4-1 4.1 4.2 Near-Tenn Improvements .................................................................................... 4-1 Long-Tenn Improvements ................................................................................... 4-3 REFERENCES ........................................................................................................................... R-1 May Creek Basin Action Plan 4/23/0 I Page Figure 1-1: Figure 2-1: Figure 3-1: Figure 3-2: Figure 3-3: Figure 3-4: Figure 3-5: Figure E-1: Figure E-2: Figure E-3: Figure E-4: Table 3-1: Table 3-2: Table 3-3: Table D-1: TABLE OF CONTENTS (continued) List of Figures Basin Vicinity Map .............................................................................................. 1-3 Water Features/Subareas Map ............................................................................. 2-5 Primary Recommendation Projects Location Map .............................................. 3-3 Subcatchment Boundaries Map ........................................................................... 3-9 Retention/Detention Standards Map .................................................................. 3-11 Zoning Map ........................................................................................................ 3-29 Secondary Recommendation Projects Location Map ........................................ 3-3 7 Lower Basin Conditions May Valley Conditions East Renton Plateau Conditions Highlands Conditions List of Tables Recommended RID Standards for New Development ........................................ 3-8 Projected Monitoring Program Activities .......................................................... 3-15 Secondary Recommendation Projects ................................................................ 3-32 Ranking the Secondary Recommendations APPENDICES Appendix A: Alternative Solutions Considered for May Valley Flooding Appendix B: Sensitive Areas Regulations Appendix C: Public Participation Appendix D: Ranking the Secondary Recommendations Appendix E: Basin Conditions -Significant Resource Areas Appendix F: Lake Boren Monitoring Data -1996 & 1997 Reports Appendix G: Recommended Actions Undertaken During Plan Development Appendix H: Dredging May Creek: Technical Summary of Alternatives Analysis May Creek Basin Action Plan ii 4/23/01 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I List of Participants King County Executive Ron Sims Metropolitan King County Council Maggi Fimia, District 1 Cynthia Sullivan, District 2 Louise Miller, District 3 Larry Phillips, District 4 Dwight Pelz, District 5 Rob McKenna, District 6 Pete von Reichbauer, District 7 Greg Nickels, District 8 Kent Pullen, District 9 Larry Gossett, District 10 Jane Hague, District 11 David Irons, District 12 Christopher Vance, District 13 Department of Natural Resources Pam Bissonnette, Director Water and Land Resources Division Nancy Hansen, Division Manager Debbie Arima, Assistant Division Manager Contributing Staff (King County) Clint Loper, Project Manager John Lombard, Lake Washington/Cedar River Watershed Coordinator David St. John, Program Analyst Brent Lackey, Lake Washington/Sammamish River Basin Steward Glenn Evans, Manager, Surface Water Engineering & Ecological Services Unit Jeff Burkey, Hydrologist Wendy Gable, Communications Specialist Mary Harenda, Senior Ecologist Susan Kaufman, Senior Water Quality Engineer Laurel Preston, Communications Specialist Katy Vanderpool, Program Analyst Don Wood, Senior Engineer Gino Lucchetti, Senior Ecologist May Creek Basin Action Plan iii City of Renton Mayor Jesse Tanner City of Renton Council Randy Connan Don Persson Kathy Keolker-Wheeler Toni Nelson Terri Briere Dan Clawson King Parker City of Renton Building/Planning/Public Works Department Gregg Zimmerman, Administrator Ron Straka, Utility Engineering Supervisor Owen Dennison, Associate Planner, Long Range Planning City of Newcastle Council City of Newcastle Council Sonny Putter, Mayor Gary Adams John Dukich Jean Garber Claudia Hirschey Pam Lee Stuart Liddle City of Newcastle Staff Andy Dempsey, City Engineer Dick Thiel, Consulting Engineer Jim Walker, Public Works Director Kevin Gross, Senior Development Engineer Contributing Staff (Consultant) Shapiro and Associates, Inc. Mike Wert, Principal in Charge Jeff Buckland, Project Manager Ed McCarthy, Senior Hydrologist Scott Luchessa, Aquatic Scientist Communication Resources Margaret Winch, President Steve Taylor, Senior Associate 4/23/01 May Creek Citizens Advisory Committee Robert Cugini, Chair John Affholter (deceased) Julie Bonwell Ginger Dickson Thomas Drummond (fonner member) Andrew Duffus William (Ed) Horne Susan Larson-Kinzer John Richardson Richard Spence, President, May Valley Environmental Council Mick Zevart May Creek Basin Action Plan iv 4/23/01 ii 0 u I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 1. EXECUTIVE SUMMARY 1.1 OVERALL PLAN GOALS The May Creek Basin Action Plan provides a set of actions to: I) address the threat of flooding of homes; 2) facilitate stormflow conveyance, stabilize steam banks and reduce erosion; 3)protect and enhance fish and wildlife habitat and water quality in the basin; and 4) prevent existing problems from becoming worse in the future. 1.2 BASIN OVERVIEW May Creek is a 7-mile-long stream in the Lake Washington watershed. The creek originates in the steep forested slopes of Cougar and Squak Mountains and in the highlands of the Renton Plateau (Figure 1-1 ). As many of its tributaries converge on the flat floodplain and wetlands of May Valley, the creek broadens and slowly flows through rural pastures, small commercial areas, and suburban development until finally slicing through a deep canyon and flowing into Lake Washington. May Valley is a natural floodplain and historically has experienced periodic and sometimes extensive flooding. Through the years, this problem worsened as channelizing of streams and development in upland areas increased stonnflows to the valley, and as natural deposition of sediment in May Valley continued to reduce the conveyance capacity of the May Creek channel. May Creek canyon, through which lower May Creek flows, is an undeveloped park in the Cities of Renton and Newcastle where soft trails may be built in the future. Expansion of access to this park and the purchase of additional lands are priorities for the cities. Many residents view May Creek Park as an important community amenity. Erosion and sedimentation occur as a result of natural processes in all stream systems. Much of the erosion and-sediment transport in May Creek is a result of development in the basin. The May Creek basin continues to provide high quality tributary habitat to the Lake Washington watershed; however, use of May Creek by salmon and other wildlife is declining due to habitat loss, erosion, sedimentation, and deteriorating water quality. As more development occurs throughout the basin, many of these problems are anticipated to worsen unless steps are taken to address these issues. For this reason, measures are needed to restore the natural functions of the basin and maintain the quality of life for those who live and work in the basin. 1.3 COMPLIANCE WITH FEDERAL RESOURCE PROTECTION LAWS It is important to note that in carrying out their jurisdictional responsibilities, the basin's Cities and King County have certain obligations for action that are founded in federal laws. Implementation of the measures recommended in this plan should help basin jurisdictions comply with the provisions of the Clean Water Act, a federal law implemented by the U.S. Environmental Protection Agency in conjunction with the Washington State Department of Ecology. More immediately, implementation of the plan will be affected by the listing of wild native salmonids under the federal Endangered Species Act (ESA). At the time of this writing, two salmonid stocks-chinook salmon and bull trout-present in the Lake Washington May Creek Basin Action Plan 1-1 4123101 watershed have beenlisted as threatened under the ESA. Additional listings for other Puget Sound salmonids may be forthcoming. Although May Creek and its tributaries do not provide physical habitat elements that would support a large presence of chinook salmon or bull trout, there has been an historic run of chinook in May Creek, and the system does provide habitat elements which still support coho salmon and sockeye salmon in addition to sea-run cutthroat trout and rainbow trout. ESA listings bring with them the potential for additional regulation of many activities of private and public landowners alike, including, for instance, land development and infrastructure maintenance. Affected activities will extend beyond those that result in direct alteration of riparian and instream areas to those whose effects (e.g., alteration of stormflows or an increase in the delivery of pollutants) would indirectly affect listed salmon or their habitat. The local response to ESA listings will probably also require the continuation or creation of monitoring programs that provide information necessary for determining the effectiveness of programs, projects, and/or regulations designed to promote species conservation and show compliance with the provisions of the ESA. 1.4 THE PLAN The following pages outline an action plan for correcting adverse conditions in the May Creek basin. In its brevity and simplicity, the plan makes a departure from traditional basin planning efforts, focusing on projects that can be completed in the next three to five years within the limits of available funding. The plan recommends solving problems at their source when feasible and suggests some land use prescriptions and development restrictions toward this end. However, in doing so, the plan attempts to make use of existing County and City policies and stormwater management controls, such as those contained in the revised King County Surface Water Design Manual (SWDM). The May Creek Basin Action Plan was developed through funding by King County and the City of Renton, with the cooperation of the City of Newcastle and input from the Citizens Advisory Committee comprised of area residents. In developing this plan, the cooperating agencies have listened carefully to the needs and ideas expressed by local basin residents at several public meetings and have considered them in their analyses. The recommended solutions in this plan are intended to address existing critical problems over the next five years without causing more serious problems in other areas of the basin. The plan is not intended to be the single answer to all the basin's problems, but to work in conjunction with other existing and proposed City and County plans. The plan also contains recommendations for projects that should be undertaken beyond the initial five-year period after the adoption of the plan. Funding sources for these projects have been identified only in general terms, although the activities these projects entail will produce results that build upon those realized from projects undertaken within the primary recommendations of the plan. The May Creek Basin Action Plan presents recommendations for solutions to problems identified in previous studies of the basin. Chapter 2 of the plan presents background on the basin, identifies existing problems, sets goals for improving conditions in the basin, and evaluates potential solutions upon which the recommendations of this plan are based. Recommendations are presented in Chapter 3. The proposed recommendations are classified as primary and secondary measures based on the anticipated availability of funding and the likelihood of implementation within the next five years. The major primary recommendations intended to deal with these goals are described below. May Creek Basin Action Plan 1-2 4/23/01 I I u I • I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I To undertake actions to reduce flooding problems in May Valley while improving its ecological health, the plan proposes property-specific measures in cooperation with local landowners. The plan also calls for a number of improvements intended to limit future increases in peak flood flows as well as removal of potential channel hazards which worsen flood conditions, including beaver dams, sediment plugs, and reed canary grass occlusions. May Creek Basin Action Plan 1-3 4/23/01 \ ~ ® Ii;, le> SEATTLE ' ' ( Y=- "" ~ Ii;, """ ~ "" '<3 ~ BELLEVUE !T_! s:3 ~ ~~ I§~ ~ e::;, 4 Figure 7-1 !Basin Vocirni~ Map May Creek Basin ____.. Basin Boundary .._.,,,-... Stream ~ lake 0 October 1998 2Miles 98101-1 mayVICINIJYmap WG ~~~:,,-~--------~-~-~ The density of upland development is a key contributing factor to the flooding that occurs in May Valley. The plan recommends that zoning densities not be increased above existing levels in upland areas draining to May Valley, including adopted pre-zoning for unincorporated areas to be annexed, unless the stonnwater impacts of the increased density can be fully mitigated. As land use in the May Creek drainage area has changed, heavily vegetated areas have been replaced with pavement and structures. This conversion of land cover has disrupted the natural hydrologic cycle; ultimately, this significantly increases runoff originating in these areas. In proposing limitations on the density of new development and the retention of strict clearing standards, the Basin Action Plan limits the increase in future runoff to May Valley while supporting a growth management goal of maintaining the character of rural areas in King County. Along with restrictions on zoning and clearing, the primary recommendations involve strict Retention/Detention standards for future development. When implemented, these measures will contribute to the protection of downstream areas from increases in both peak flows and flow duration. In addition to these regulatory standards, flooding issues in May Valley are addressed by capital project recommendations aimed at both reducing the flood flows into the valley, and improving the low-flow, "ditched" section of May Creek channel to provide better aquatic habitat and to reduce flooding durations following storm events. These projects will be the top priority capital construction components for King County's implementation of this plan. Several stream restoration projects also are proposed to improve degraded conditions or provide additional habitat throughout the basin. The plan would set the stage for potential improvements in the May Creek delta; improve fish habitat and stream stability by introducing additional large woody debris in May Creek Canyon; provide slope-stabilization measures to limit erosion and sediment delivery to the creek; and provide small conifer plantings throughout the basin to improve streambank stability, moderate stream temperatures, and become a source for vital organic inputs (e.g. large woody debris) to the stream over the long term. In key locations, projects proposed in the plan would eliminate fish-passage barriers in order to improve upstream access for species using May Creek and its tributaries. The plan recommends the use of existing water quality programs in the County and Cities to resolve the May Creek basin's most pressing water quality problems. Implementation of key objectives of water quality programs of the King Conservation District, the Seattle-King County Health Department, and others will also help promote efforts to protect surface and groundwater resources. Finally, the plan contains a proposal for the establishment of a Basin Steward who would work with local property owners, businesses, and the development community to improve surface- water conditions in the basin through education, coordination, and implementation of many of these projects. In addition to identifying the most important recommendations for action in the basin, the plan identifies potential funding sources and implementing agencies for each action. The primary recommendations would be funded and implemented by a range of entities, including the Cities of Renton and Newcastle and King County. May Creek Basin Action Plan 1-6 4/23/01 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Secondary recommendations are proposed to provide longer-term solutions to issues similar to those addressed by the primary recommendations. Funding sources for secondary recommendations can be identified only to a very general level of detail. For this reason, the implementation schedule for these measures is uncertain. The secondary recommendations are shown in a prioritized order derived from a ranking process described in Appendix D. In addition to those projects that might be funded directly through agency involvement in the basin, secondary recommendations also include several projects that might be accomplished as mitigation measures for future development activities. Chapter 4 presents the expected results of the recommendations made in Chapter 3. During the first three to five years of implementation of this plan, King County would pursue resolution of the worst flooding problems encountered by basin residents in recent years. The plan is also expected to help restore May Creek fish habitat and riparian areas in general. Through cooperative measures and the use of appropriate development standards, the plan would help perpetuate the improvements put in place now through stewardship and public education efforts. As the recommended plantings mature, they will discourage non-native invasive species from becoming established. Habitat diversity would increase, at least in localized areas, which in tum would provide the foundation for an increase in the diversity of wildlife that would reside in or pass through the basin To ensure successful implementation, this plan recommends formulation of a monitoring program to enable basin agencies to determine the effectiveness of the proposed measures. The monitoring program will provide evaluation criteria for measuring the performance of specific actions and projects to ensure that desired goals are being met, and will be designed at a scale appropriate to the level of capital projects being implemented in the basin. The monitoring and evaluation process allows for corrective actions and adjustments to be made when actions and projects are not producing the desired results. Monitoring also will help agencies and citizens ensure that the improvements achieved through implementation of the plan will continue to be effective and meaningful in the future. Monitoring undertaken to help determine plan effectiveness will likely be coupled with monitoring undertaken as part of ESA response to help identify the effectiveness of broader local efforts to conserve species and comply with regulatory requirements. May Creek Basin Action Plan 1-7 4/23/0 I I I I I I I I I I I I I I I I I I I I 2. 2.1 INTRODUCTION About This Plan This plan has been funded by King County and the City of Renton Surface Water Utility. The City of Newcastle incorporated after a substantial portion of the plan was completed. It has not provided funds for the plan, but has participated in its development in a review capacity. The City of Newcastle has completed and adopted its own Stormwater Management Comprehensive Plan (SMCP). While Newcastle's SMCP and this plan contains similar recommendations for surface-water management projects derived from the hydrologic conditions in the basin, the Newcastle SMCP addresses surface-water concerns for areas outside of the May Creek basin within the City .. The City of Newcastle will coordinate with King County and the City of Renton in commencing implementation of recommended actions before completion of the SMCP if circumstances warrant more immediate action for certain projects. Newcastle formally adopted this plan in late 2000, and the City of Renton plans do so in April or May 2001. Basin planning has been undertaken recognizing that urban activities contribute to changes in the natural characteristics of watersheds that frequently threaten healthy watershed systems. The focus of basin plans has been on reducing flood damages, protecting stream and wetland habitats, and improving the quality of surface and groundwater. The primary goals of the May Creek Basin Action Plan are the following: o Reduce the threat of flooding to citizens in the May Creek Basin; o Make infrastructure improvements that will facilitate stormflow conveyance, stabilize stream banks, and reduce erosion; o Protect and enhance fish and wildlife habitat and water quality in the basin; and o Take reasonable steps to prevent existing problems from worsening in the future. This plan contains strategic recommendations to correct or reduce problems identified through the planning process. The plan also provides guidelines for future actions with the objective to improve overall conditions within the basin. As with all natural systems, watersheds are comprised of relationships between land use, water quantity, water quality, and aquatic habitat. As a result of these relationships, activities in one part of the basin influence, and in turn are influenced by, activities elsewhere. These relationships are particularly relevant to the consideration of proposed remedies to problems in the basin. For example, erosion control cannot take place effectively without consideration of the high water flows that cause erosion, and aquatic habitat cannot be maintained or restored and effectively managed without considering the land uses and hydrologic conditions that surround important habitat areas. Because this is one of many ongoing planning and implementation efforts undertaken by the basin's three jurisdictions, there are limitations on funding and resources available to provide the many improvements that are desirable in this basin and other basins for which the jurisdictions are responsible. Therefore, a portion of the recommendations made within this plan will be implemented within three to five years, while others may not be accomplished for many years. Actions recommended by the plan are separated into primary and secondary recommendations based on ranking criteria applied to each of the problems identified for the basin, along with the feasibility and availability of funding for each solution. Ranking criteria included flooding May Creek Basin Action Plan 2-1 4/23/01 frequency, severity, and the potential for damage to human health, property, and important fish and wildlife habitat. In categorizing recommendations, those that directly address the most significant problems and are expected to be within the funding capability of these local sources are considered primary, with the understanding that the provision of funding from King County and the Cities of Renton and Newcastle for implementation of the recommendations will require approval by their respective Councils. Other, more long-term solutions without definite funding were defined as secondary recommendations. This methodology for distinguishing between recommended actions differs somewhat from that used in other Basin Action Plans and has resulted in more attention being focused on implementable solutions while still providing a comprehensive approach to addressing problems in the basin. In addition to providing near-term improvements to May Creek surface-water conditions, this plan should provide a foundation upon which to build efforts for long-term improvements. 2.2 FUNDING SOURCES AVAILABLE FOR IMPLEMENTATION Most of the projects identified in the May Creek Basin Action Plan are expected to be implemented by one of three jurisdictions in the May Creek basin: the Cities of Renton and Newcastle, and King County. Each jurisdiction has a public works or surface-water utility that is responsible for planning efforts and implementation of capital projects related to flood reduction, habitat restoration, and water quality improvement. Each jurisdiction has responsibility for geographic areas broader than the May Creek basin, however, and therefore must prioritize its use of financial resources across its entire jurisdiction. The King County Water and Land Resources (WLR) Division, formerly known as the Surface Water Management Division, has established a process to prioritize capital expenditures across its service area. WLR's large project capital program is funded by bond revenues. The most recent bond issues in 1992, 1995, and 2000 have been used for construction of high priority projects throughout the County, most of which have been completed. New priorities for capital projects are determined each year based on capital needs throughout the unincorporated portions of King County. As of March, 2001, funds allocated for May Creek Basin Action Plan implementation totaled $840,000 from 1995 and 2000 capital bonds and King Conservation District funds. Of this amount, approximately $290,000 has been expended for one property purchase and structure demolition; data gathering and assessment, survey, and mapping; and preliminary design work on valley and ravine projects. Although funding from WLR for major projects recommended in this plan is presently limited to the amounts in the current project budgets, additional funding may be available in the future from new bond issues or "pay as you go" (annually budgeted) capital funding. Future capital funds will be allocated across multiple watersheds according to WLR's countywide capital priorities, so funding available for projects in May Creek basin will vary from year to year. In addition to CJP bond-funded projects, WLR has contributed in the past, and will continue in the future to contribute funds to recommended projects through the Small Habitat Restoration Program, the Drainage and Habitat Improvement Program, and the Neighborhood Drainage May Creek Basin Action Plan 2-2 4/23/0 I I I I I D I I I I I I I I I I I I [I I I I I I I I I I I I I I I I I I I I I Assistance Program, if circumstances allow. These funds, awarded to projects costing up to $70,000, are distributed on a competitive, priority basis and are largely limited to use on projects within the King County surface-water management service area. The King County Department of Transportation represents another important participant in, and source of funding for, implementation of Basin Action Plans in King County. The Department of Transportation maintains several databases of priority projects based on a variety of factors. Currently, the two projects focused on the major bridge crossings of May Creek in May Valley do not rank high enough for funding in the near future and therefore are secondary recommendations. Several smaller projects focused on culverts, for example the culvert at S.E. May Valley Road at the East Fork of May Creek, are prioritized differently and are likely to be funded. The WLR Office of Open Space has recently contributed to improvements in the basin through the purchase of parcels at the Pacific Topsoils quarry site, with the intent of maintaining that land as open space with a public access element. The Office of Open Space will be pursuing additional purchases of open space at this old quarry site. The City of Renton Surface Water Utility's proposed six-year CIP currently identifies a need of $550,000 for implementation of recommended capital projects in future years in the Renton portion of the May Creek basin. The availability of this funding is subject to approval by the Renton City Council. Newcastle staff have indicated that a high importance is placed upon May Creek basin surface- water issues, especially in the Lake Boren/Boren Creek sub-basin. The City of Newcastle has developed a Storrnwater Management Comprehensive Plan (SMCP) identifying its needs and anticipated costs in addressing storrnwater issues in its jurisdiction. Newcastle's SMCP is intended to work in concert with this Basin Action Plan for that portion of the City located in the May Creek Basin. Because major capital funds may be limited, Newcastle expects to concentrate on projects that are already budgeted, such as several road improvement projects, and incorporate surface-water needs as appropriate and feasible. In addition to these major funding sources, project funding from additional sources also may be available. State, federal, and private grant funds, or mitigation dollars resulting from major developments or infrastructure projects in the basin, such as the expected widening of SR 900 or of 1-405, may be available for some measures. Funds from the Cities of Renton and Newcastle are expected to raise the total May Creek basin capital budget to almost $2 million. This money will represent a significant contribution to protecting and enhancing environmental quality within the basin. The need for surface-water improvements in the basin, however, is much greater than what the $2 million figure implies. The secondary recommendations, which may be implemented as additional funding becomes available, represent more than $20 million of long-term improvements. The establishment of a Basin Steward -a primary recommendation in this plan - will provide a person within the basin to serve as an advocate for continuing efforts to improve local conditions, including those specified for actions in the secondary recommendations list. As King County and the Cities of Renton and Newcastle monitor the results of implementing this May Creek Basin Action Plan 2-3 4/23/0 I Basin Action Plan, it is expected that additional funding for important projects will be identified as part of their respective surface-water management programs. 2.3 THE MAY CREEK BASIN The May Creek basin encompasses an area of 14 square miles that drains to the southeast portion of Lake Washington (Figure 2-1). May Creek is approximately 7 miles long. It is the primary stream within the basin, but the basin also contains numerous tributaries, including Honey Creek, Boren Creek, and the North, East, and South Forks of May Creek. Two lakes also are located within the basin: Lake Kathleen in the southeast portion of the basin and Lake Boren in the northwest portion of the basin. The basin has been divided into four regional subareas (Figure 2-1 ), or subbasins, for analysis and discussion: o Lower Basin Subarea -extending from the mouth of May Creek at Lake Washington upstream to River Mile 3.9, above the Coal Creek Parkway S.E. crossing; o May Valley Subarea-the floodplain of upper May Creek and the adjacent lower valley areas from River Mile 3.9 to the hydrologic divide to the east; o Highlands Subarea -the area lying north of May Valley and east of the Lower Basin, including the steep southern slopes of Cougar Mountain and the southwest portion of Squak Mountain; and o East Renton Plateau Subarea -the area lying south of May Valley and east of the Lower Basin Subarea. The basin was the site of hunting and fishing by early settlers who later conducted mining, logging, and farming operations within the region. Since that time, land use within the basin has changed to more intensive residential use in its western portion, while retaining a mix of rural residential, small farms, and some forest land in the east. The western one-third of the basin has been incorporated by the Cities of Renton and Newcastle, and the remaining area is in unincorporated King County. Although City boundaries are expected to expand somewhat in the future, the Urban Growth Area Boundary bisects the basin at 148th Avenue S.E., ensuring that the eastern half of the basin will remain rural for the foreseeable future. May Creek Basin Action Plan 2-4 4/23/01 I I I I I I I I I I I I I I I I I --- Lake H-'<1~hi11strm - ._,-. Basin Boundary - ~ ... ''"' Subarea Boundary ~ Stream & Stream Number = lake 50= Wetland & Wetland Number c=J Incorporated Areas ------ ' i l ________ , I '------,., ~)" ' ""' '1 /)59 o;'"'in" ,,,1'·- B;;, f;'r· .( 0 -rec{ /P ~810 -"-s, " , ... , ,--- i I i ,, ' I ,---......... {1;,.54 ,.., ... ,, I --Ll \ .$5~ ' I \d~ I I ' ' . • 1 28b I -+>" 1,~ -......._;,..____ L "~ ,,:,1. '),l~r.r1, (, •, .. /''!, ·" /, ------- Figure 2-1 Water features/Subareas Map May Creek Basin HIGHLANDS C-;, ~~~,:. \, '! ~ -'" ;,_ "T' I ~ -~ "' ,,,~ ·~··· N * 0 1/2 1 Mile October 1998 - 9810 2-lWdtl'rfeatures-SubAreas WG I I I I I I I I I I I I I I I I I I I May Valley is largely composed of a natural floodplain that periodically filled with floodwaters even before this region was settled. Development in the basin has reduced forest cover, increased impervious surface area, and filled in wetlands. All of these changes have aggravated the valley's natural, periodic flooding regime. The amount of effective impervious area has increased to a basinwide average of 7% under current conditions. Most of this impervious surface is in the Lower Basin Subarea. Without any changes in zoning or development protections, the amount of impervious surface is expected to increase to 12% in the future. The change from a predominantly forested basin to one with an increasing percentage of impervious surface has had significant hydrologic implications. This change has caused the amount of stormwater runoff to increase throughout the basin, dramatically in some locations. Flood flows have increased as well, resulting in additional erosion of hillsides, flooding and sediment deposition in the valley, erosion in the canyon downstream of the valley, and flooding and deposition near the mouth of May Creek. Human activity in the basin also has affected local water quality. Pollution from businesses and agricultural processes, road and highway runoff, and residential septic tank failures have contributed to the degradation of May Creek and its tributaries. In addition, reductions in base flow to streams and removal of riparian vegetation have increased water temperature. Collectively, impacts associated with human activities have reduced the habitat value of local streams, which has reduced the capacity of the May Creek system to support migratory and resident salmonids. These impacts also increase the risks to the quality of underground drinking water supplies, critical to residents of the basin and the City of Renton. Because human use of the basin is expected to increase in the future, these concerns must be addressed to improve existing conditions and prevent further deterioration of watershed resources important to humans and native wildlife and plants. 2.4 CONDITIONS WITHIN THE BASIN Recent basin management planning began with preparation of the May Creek Current and Future Conditions Report issued by King County and the City of Renton in August 1995. This report assesses current conditions and predicts future trends in the May Creek basin. The report also identifies significant conditions and issues to be addressed in the May Creek Basin Action Plan. Key findings of the Current and Future Conditions Report include the following: o The dominant hydrologic function of the May Valley is storage of floodwaters. Substantial storage occurs in the valley floodplain. In performing this function, May Valley is sometimes subject to long-duration flooding, which in turn directly contributes to reduced peak flood flows downstream. Removal of the substantial storage in May Valley could increase these downstream flood flows by as much as 30%. Currently, retention/detention ponds are not required for most low-density residential development in areas draining to May Valley. Furthermore, reductions in flooding that would result from construction of such ponds would be limited because flooding in the valley is primarily caused by the volume of water, which would be delayed, but not reduced, by such retention and detention structures. May Creek Basin Action Plan 2-7 4/23/01 o The most extensive flooding problems in the May Creek basin occur in May Valley. Through the years, development, dredging, and filling within the May Creek floodplain have altered natural drainage patterns, reduced natural storage areas, and placed structures in the path of floodwaters. Runoff from future development is expected to cause an increase in flood volumes in the valley, resulting in longer durations of floodwater inundation and greater frequency of flooding, but only slightly greater flood depths. Residential development in May Valley, with the establishment of homes and properties in the valley's wetland and floodplain complex, has resulted in occasional damage to private structures and frequent flooding of pastureland. It is estimated that at least seven homes and one business are located within the 100-year floodplain. Peak flows have increased moderately in the valley, on the order of 15 to 20% greater than the predevelopment conditions for the 2-, 25-, and I 00-year events. Flooding, however, is not solely determined by the size of peak flows; it is also a function of floodwater volumes and flow durations. High groundwater levels in winter are likely a factor as well. Several local properties experience pasture flooding and ponding of long duration (sometimes over several months). The valley floor becomes saturated, and the low gradients of the floodplain overbanks do not permit drainage to occur efficiently. Similarly, when major storm-related flooding occurs, the floodwaters recede very slowly. It is this frequency and duration of even low-depth flooding, rather than the size of flood peaks, that has increased substantially over the years as development of upland areas has occurred. While May Valley is the site of the most extensive flooding in the basin, less severe drainage problems occur in other parts of the basin. Localized drainage problems in the basin are mainly related to past alteration of natural stream channels, filling natural detention areas, undersized conveyance systems, development with inadequate mitigation, or improper installation of drainage measures, which results in increased runoff to downslope properties. Of the current localized drainage problems, the majority are concentrated in urbanized portions of the basin. o Sediment deposition has occurred from natural erosion but has been accelerated by increased storm flows from development and changes in local land cover. Sediment deposition has been a problem in two important locations within the basin. First, sediment eroded from streams in the Highlands and East Renton Plateau is gradually reducing the capacity of the May Creek channel in May Valley. This sediment accumulation has contributed to worsening flood problems and degradation of fish habitat. Secondly, increased flows have resulted in erosion of the May Creek Canyon and lower basin tributaries, and this sediment is interfering with commercial business operations on Lake Washington where the sediments are deposited. An average of approximately 2,000 cubic yards per year are dredged from the mouth of May Creek on Lake Washington. Stream flows are expected to increase as development expands throughout the basin, especially in the Highlands and East Renton Plateau Subareas. This will increase erosion and downcutting of stream channels, leading to increased sedimentation. In addition, loss of stream-side vegetation, poor construction practices, and quarry runoff also contribute to erosion and sedimentation within the basin. May Creek Basin Action Plan 2-8 4/23/01 ii I I [I I B I I I I I I I I I I I I I I I I I I I I I I I I I I I • I I I o Nonpoint pollution is another concern within the basin. Major sources of nonpoint pollution include runoff from roads, quarries, developing sites, and commercial operations; animal- keeping practices and grazing in riparian areas; and failing septic systems. Urbanization of the basin is expected to increase nonpoint pollution concentrations, thereby affecting water quality and aquatic habitat values. High concentrations of fecal coliforrns and total phosphorus are of particular concern to water quality. Improper livestock management practices and failing septic systems are the primary causes of fecal coliform problems. Consistently high fecal coliform levels were found in the May Valley and upper basin areas, as well as at the mouths of Honey and China Creeks. As well as impacting instream habitat, high levels of fecal coliforn1s can threaten recreational uses such as swimming and wading. Fecal coliforms also could contaminate groundwater, a cause for concern as this area is within the City of Renton's aquifer protection zone. Storrnwater phosphorus loading has resulted in concentrations within May Creek well above U.S. Environmental Protection Agency guidelines for streams that discharge to lakes. The concentrations are sufficiently high to potentially threaten aquatic life. Phosphorus levels are expected to increase as further development in the basin occurs. o Development activities within the basin have historically degraded stream and wetland habitats. Filling of wetlands, increased stormwater runoff and peak stream flows, addition of sediment and pollutants to the water, and removal of coniferous forest cover have contributed to the degradation of local habitat in the basin. The lack of adequate quantities of large woody debris (LWD) within basin streams limits habitat complexity and results in a relative scarcity of pools, an important component of stream habitat. For woody debris to be effective, it must be of sufficient size to alter instream hydraulics and durable enough to remain in place for many years. The lack of high quality LWD accelerates downcutting in stream channels and the build up of sediment at the mouth of May Creek. Wetlands within the basin also have been threatened by development. Almost every one of the basin's nearly 80 identified wetlands has been disturbed by deforestation, filling, draining, agricultural practices, or buffer removal, with much of this disturbance occurring after the wetlands were first inventoried in 1983. Without proper land use controls, stream, wetland, and lake habitats will continue to be damaged by ex isling uses and future development. Subsequent to identification of existing conditions and areas of concern in the Current and Future Conditions Report, project consultant Foster Wheeler Environmental Corporation issued two reports for review by King County and the City of Renton analyzing possible solutions. The May Creek Basin Phase I Solutions Analysis was issued in November 1995, followed by the May Creek Basin Phase 2 Solutions Analysis in May 1996. Both of these reports include assessments of the main problems within the basin. The Phase I Solutions Analysis combined problems into five categories: May Valley flooding, Lower May Creek sediment erosion and deposition, major site erosion, May Valley habitat problems, and May Creek basin habitat restoration and enhancement. Preliminary recommendations were included within the Phase I May Creek Basin Action Plan 2-9 4/23/0 I Analysis, which led to the considerations made within the Phase 2 Analysis for a set of comprehensive approaches to address basin problems. 2.5 POTENTIAL SOLUTIONS The solutions recommended in this plan were developed to help basin jurisdictions meet the primary goals noted on page 2-1. These solutions use the results of the solutions analysis and the key findings in the Conditions Report and recognize that measures taken to resolve the identified problems must occur in the context of existing land uses in the May Creek basin. In the case of peak flood flows, it is acknowledged that much of the basin has already been either developed or platted and is therefore vested as far as future locally mandated drainage requirements are concerned. In some instances, future development is expected to occur at densities below the threshold at which local stormwater management standards would be triggered and mitigation measures would be implemented. Thus, new approaches to resolving future flow-related problems that are reliant on stricter development standards would have limited utility. This plan can effectively influence stormwater impacts from the small areas of higher density development through the specification of appropriate retention/detention standards as contained in the SWDM. Given the financial limitations associated with implementation of this Basin Action Plan or plans like it, all of the flooding problems in May Valley cannot be solved at once. Goals for reducing flooding under this plan are, in order of priority, as follows: (l) to eliminate significant public safety hazards; (2) to alleviate frequent flooding of homes and sole access roads; (3) to reduce flooding of septic systems and wells; and (4) to reduce the financial and social burden of pasture flooding. Key limitations in addressing flooding concerns are that these goals must be met without causing downstream impacts or impacts that substantially affect species protected by the ESA, as well as meeting all other relevant permitting requirements. Increases in erosion resulting from increasing stream flows are difficult to resolve; however, an array of instream measures can be effective at reducing the rate of downstream sediment transport while also increasing habitat area. Resolving erosion problems near their source is the most cost-effective way of addressing such problems, but the discussion above regarding limitations in mitigation for future development has implications for sediment as well. Beyond this recommendation, it will be important for regulating agencies to recognize that sediment deposition is a problem in portions of May Creek as they consider permits for future basin activities. Nonpoint pollution sources in the May Creek basin include the following: o failing septic systems; o roadways; o livestock; and o commercial/industrial areas. All of these sources are present and problematic in other areas of the County as well. As the sources are reflective of the impacts of many widespread land use actions, capital facilities are generally not an effective tool to address these problems. Instead, Countywide programs have been developed to address them. These programs emphasize education, technical assistance, and May Creek Basin Action Plan 2-10 4/23/01 I I I I I I • I I I I I I I i I I I I I I I I I I I I I I I I I I I I I other measures that help address the nonpoint pollution problem. In addition, the City of Renton has developed programs to protect groundwater and drinking water supplies. Rather than address such issues individually through this plan, these Countywide and Citywide programs represent a comprehensive approach to dealing with these problems. Several of this plan's recommendations encourage local agencies to target specific portions of May Creek when implementing development guidelines or land use practices under existing programs. Many of the projects included in the Basin Action Plan's recommendations would improve water quality by addressing pollution from businesses and agricultural activities, runoff from local roads, and residential septic tank failures. Recommendations that correct these problems also will protect underground drinking water supplies. A number of the recommended actions would result in the retention of open space and natural areas that are important in providing adequate land for groundwater recharge. Although habitat degradation is widespread throughout the basin, this plan recommends public funding of only the most cost-effective solutions to the most significant problems. While local restoration of certain habitat areas has merit, perhaps more important is the need to restore stream and watershed processes and functions so that existing and restored habitat structure can be more self-sustaining in the future. Thus, actions such as reforestation of important reaches of the stream corridor are high priorities, along with measures that will provide more immediate benefits, such as installation of site-specific habitat-protection structures. Overall, this plan reflects an action-oriented agenda for eliminating or reducing the impacts of a variety of problems reviewed in previous studies of the basin. In addition to the potential solutions identified here, Chapter 3 also contains a brief discussion of other solutions considered but detennined infeasible. These alternative approaches are summarized in Appendix A. 2.6 AGENCIES WITH ROLES IN MAY CREEK BASIN MANAGEMENT Planning within the May Creek basin has been undertaken to determine cost-effective approaches for protecting environmental quality and reducing flood damages. The May Creek Basin Action Plan is the result of efforts by several agencies and many concerned citizens, including a Citizens Advisory Committee, and input from the May Valley Environmental Council, to implement measures focused on correcting existing problems and maintaining the integrity of natural resources. The primary agencies involved in development of this plan have been WLR and the Surface Water Utility of the City of Renton, which have shared costs in plan development. Along with the King County Department of Development and Environmental Services and the City of Newcastle, these agencies are responsible for administering development regulations for a variety of activities within the basin. The three jurisdictions have coordinated closely on plan recommendations. Newcastle, since incorporation, is responsible for approximately 20% of the land area in the basin. Renton is responsible for approximately 12% of the basin, and King County is responsible for the remaining 68% of the area. The land area of the two cities will increase as they annex lands within the Urban Growth Boundary. As part of its watershed management responsibilities, King County has been preparing Basin Action Plans for urbanizing areas of the County over the past decade. This plan identifies surface-water problems within the basin and proposes near-and long-tenn strategies to address these issues. May Creek Basin Action Plan 2-11 4/23/01 Several additional agencies at the regional, state, or federal level are responsible for various activities affecting resource management in the May Creek basin. The regional agencies include the King County Wastewater Treatment Division (fom1erly Metro), King Conservation District, Washington State University Cooperative Extension Service, and the Seattle-King County Department of Public Health. King County Sewer and Water District 107 provides sewer and water service, and King County Water District 90 provides water service within the area. The state agencies involved include the Department of Ecology, Department of Health, Department of Agriculture, Department of Natural Resources, Department of Fish and Wildlife, and the Department of Transportation, as well as the Puget Sound Water Quality Action Team. Federal agencies include the Army Corps of Engineers, Environmental Protection Agency, U.S. Fish and Wildlife Service, National Marine Fisheries Service, Federal Emergency Management Administration, U.S. Geological Survey, and the Natural Resources Conservation Service. In addition, the Muckleshoot Indian Tribe co-manages fishery resources in the basin, as the entire May Creek basin lies within the tribe's Usual and Accustomed fishing grounds. May Creek Basin Action Plan 2-12 4/23/01 I I I D I I I I I I I I I ·• I I I I I I I I I I I I I I I I I 3. 3.1 RECOMMENDATIONS SUMMARY OF PRIMARY RECOMMENDATIONS Potential solutions to problems in the May Creek basin have been categorized as primary recommendations or secondary recommendations. Primary recommendations are either policy decisions that do not require additional public funding, or programs and projects that are anticipated to be implemented within the next three to five years, based on the availability of funding and their relative importance. Secondary recommendations, while considered important, involve projects for which funding is not ensured, and for which the time frame for implementation may extend beyond the three-to five-year interval after adoption of the plan. Concurrent with the development of this plan, basin jurisdictions have undertaken a range of activities that support the broad long-term goal of improving basin conditions. While many of these actions did not directly overlap with discrete, project-oriented recommendations proposed during plan development, several of these actions did do so. These recommendations, as they have largely been acted upon, have been removed from the list of primary recommendations and presented in Appendix G with a description of their current status. Primary recommendations are summarized below. More specific details about the recommendations follow the summary. A map showing the locations of the projects identified in the primary recommendations is provided in Figure 3-1. Secondary recommendations are presented in prioritized order in Table 3.3 at the end of this chapter. Basinwide Recommendations I. Establish and Enforce Requirements for Runoff Retention/Detention, Forest Retention, and Water Quality Facilities for Site Development 2. Develop Basin Stewardship and Community Coordination and Participation through the Creation of a May Creek Basin Steward 3. Establish a Monitoring Program to Determine the Effectiveness oflmplemented Plan Actions May Valley Subarea 4. Provide Cost-Sharing and Technical Assistance for Flood Protection in May Valley 5. Remove Flow Obstructions from the Channel of May Creek in May Valley 6. Restore Flows Diverted from Tributary 0294 back into Tibbetts Creek 7. Enlarge the Culvert under S.E. May Valley Road at the East Fork of May Creek 8. Protect Habitat at the Confluence of May Creek and Its Tributary Streams Lower Basin Subarea 9. Work Cooperatively to Protect the City of Renton Drinking Water Supply I 0. Facilitate Permitting for May Creek Delta Dredging 11. Stabilize the Slopes at the Most Significant Erosion Sites in May Creek Canyon Related to Surface Runoff Discharges 12. Place Large Woody Debris in May Creek in May Creek Canyon 13. Plant Conifers Throughout the Riparian Area in May Creek Canyon May Creek Basin Action Plan 3-1 4/23/01 I I I I I I I I I I I I I I I I I I I East Renton Plateau and Highlands Subareas l 7. Require Full Mitigation for Future Increases in Zoning Density in Areas Draining to May Valley May Valley and Highlands Subareas l 8. Reduce the Potential for Negative Water Quality Impacts Originating at the Basin's Quarry Sites May Creek Basin Action Plan 3-3 4/23/0 I 3.2 DETAILED PRIMARY RECOMMEND A TIO NS The following section provides a detailed discussion of the recommendations listed above. Basinwide recommendations are presented in Section 3.2.1 followed by recommendations for projects presented by subarea. Recommendations were developed to deal with a variety of conditions in the basin as discussed in Section 2.4. These primary recommendations are not necessarily identified in priority order. They were developed as a package to provide the overall greatest benefits to the basin within the anticipated funding limit. 3.2.1 Basinwide Recommendations 1. Establish and Enforce Requirements for Runoff Retention/Detention, Forest Retention, and Water Quality Facilities for Site Development. Implementing Agencies: King County Water and Land Resources Division and Department of Development and Environmental Services, City of Renton, City of Newcastle. Cost: No direct public cost. Recommendations: Retention/Detention: Maintain appropriate standards for retention and detention (RID) for all new development within the May Creek basin (Figure 3-2). Most of the basin should is governed by a Level 2 (Stream Protection) standard, which is intended to limit future increase in runoff into May Creek. Areas draining to Lake Boren should continue to be governed by a Level 3 (Lake Protection) standard, which is intended to limit future increases in Lakeshore flooding for all events through the 100-year flood. Active or inactive quarry operations should continue to be governed by a Level 4 standard, which requires the completion of Master Drainage Plans for large, complex sites, including mineral areas. The Renton drainages to May Creek downstream of Honey Creek are governed by a Level I (Conveyance) standard, which is intended to ensure adequate culvert capacity and prevent the overtopping of roads. These sub-basin specific standards have been incorporated into the Surface Water Design Manual (SWDM) by King County and Renton's and Newcastle's drainage codes which are the substantial equivalent. Forest Retention: Restore the 65% forest retention requirement (35% clearing limit) of the former May Creek Critical Drainage Area in addition to the RID standards described in the above requirement in all rurally zoned lands which drain to the May Valley sub-basin. Water Quality: Maintain standards at least equivalent to the minimum requirement of the SWDM throughout the basin. Discussion: The SWDM contains standards for retention/detention (RID) and water quality for King County. It establishes four levels of RID for site development as described in the above recommendation. The standards for any given area are based on downstream areas that are affected by development; areas with higher resource values or greater flooding problems warrant more upstream protection through higher standards. The manual also allows for a combination of retention of forest cover on a parcel and construction of retention/detention facilities for large, rural lot development to ensure that downstream areas are May Creek Basin Action Plan 3-6 4/23/0 I I I I I I I I I: I 1: I I I I I I I I I I I I I I I I I I I I adequately protected. Clearing limits are set in the King County Clearing and Grading Code 16.82. Presently, development is held to either a 65% forest retention standard without RID, or a 40% forest retention standard with stormwater facilities consistent with the SWDM Level 2 RID required for rurally-zoned areas in the basin. Many standards in the SWDM were originally set for specific areas of the County through the adoption of Basin Action Plans. In May Creek, a Critical Drainage Area (CDA) public rule was enacted in 1993 that required all development in unincorporated portions of the basin to adhere to essentially a Level 2 RID standard. In addition, the CDA required rural lot developments to maintain 65% of the developed land in pre-development vegetation, which is similar to requirements adopted for the Issaquah and Bear Creek basins. Within Renton and Newcastle, the current standards are equivalent to a Level I RID requirement. Upon adoption of the Revised Surface Water Design Manual in September 1998, the CDA standards were replaced by the SWDM. Newcastle RID standards have also been replaced in the basin through that city's adoption of the 1998 King County Manual. This recommendation sets appropriate standards for each sub-basin (Figure 3-2) within the May Creek basin because it is expected that the Cities of Renton and Newcastle have adopted standards consistent with those in the SWDM. These recommended standards are included in Table 3.1 below. In most of the basin, new development would be required to control both peak flows and flow durations. In the sub-basins draining to Lake Boren, new development also would be required to ensure that lake flooding is not worsened. Portions of the lower basin within the City of Renton, where much development already has occurred, are recommended for a peak flow standard (Level I) only (Figure 3-3). A Level 3 RID standard was considered for the area draining to Lake Kathleen; this area has been given a Level 2 RID standard based on the limited opportunity for additional development to occur in that drainage area. Primarily this is because application of such a standard in that area would not produce greater benefits than those gained from applying a Level 2 RID standard. King County Code 16.82 presently allows the choice of either 65% forest retention or construction of RID for rurally-zoned developments combined with 40% forest retention. The standards associated with the former CDA designation were stricter, however, and required that both 65% of existing forest be maintained and Level 2 RID be constructed. The Level 2 RID requirement in the SWDM is quite effective at limiting future increases in both tributary flooding and erosion which mainly result from the extreme quantities of peak stormflows, but it does not address the overall stormwater runoff volumes. While constructed infiltration facilities are ineffective due to poorly percolating soil types in most areas of the basin. Analysis has shown that maintaining portions of a developed site in existing vegetation is also an effective means of controlling stormwater volumes-the forest lands that are retained store rainfall within the forest canopy and the forest duff layer, allowing significant evaporation and natural infiltration into the groundwater system. On rurally zoned lands, lot sizes are large enough that a forest retention standard is both practical and beneflcial in reducing stormwater volumes. The combined approach of both forest retention and Level 2 RID upstream is very important for reducing future flood-flow increases in May Valley. Hydrologic analysis suggests that even 40% forest cover combined with Level 2 RID can be effective in limiting future increases in flooding and erosion. This was the basis for using that May Creek Basin Action Plan 3-7 4/23/01 standard in the current Surface Water Design Manual. While a 40% forest retention standard may be virtually equivalent to the former standard of 65%, the flooding volumes and associated impacts to the community are sufficient that the stricter 65% standard should be applied to all development of rural lands draining to May Valley. As of January 2001, King County along with other jurisdictions are presently negotiating a new set of countywide surface water design standards as an element of the forthcoming Endangered Species Act 4( d) Rule regarding threatened chinook salmon. Currently these new design standards are proposed to mandate both King County-wide 65% forest retention/JO% maximum impervious cover limit in all rural areas, in addition to a new two-pronged approach to retention/detention. This approach will give property developers a choice between the construction of the current SWDM facilities (Level 2 RID), and a new best-management-practice called "full dispersion". Full dispersion will require that all surface water runoff be dispersed over a flat, I DO-foot long flow-path through native vegetation. This option is being offered because hydrologic models show it to be as effective as Level-2 RID for limiting downstream flow-rates. These changes to the drainage code are anticipated in the near term (200 I), because stricter standards are expected to be adopted through the 4( d) rule process. If the expected code changes are not implemented by King County through the 4(d) process, then the stricter requirements described above should be codified separately for the May Creek basin. For water quality protection, the SWDM presents several levels of treatment standards dependent on the project location and its effect on downstream resources. For each standard, specific measures could be selected from a variety of options to ensure that new development projects adequately meet the performance objectives for treatment of stormwater runoff. These measures tend to benefit groundwater resources as well. In particular, phosphorus-sensitive lakes often merit higher treatment standards for development in upstream areas. The necessary analysis to determine whether a lake (e.g., Lake Boren) is phosphorus-sensitive (and whether stricter standards would be an effective method of improving lake conditions) is beyond the scope of this Basin Action Plan and the basinwide conditions analysis that preceded it. For now, the water quality protection standards in the SWDM should be maintained for all areas of the basin. The Cities of Renton and Newcastle have adopted the SWDM or equivalent standards for water quality treatment. In the future, a Lake Management Plan should be considered for Lake Boren, as discussed in Basin Action Plan Recommendation 14. Such a plan would assess whether a higher level of required water quality treatment would significantly improve the health of the lake. May Creek Basin Action Plan 3-8 4/23/01 D I I I I I I I I I I i I I I I I I I I I I I I I I I I I I I I Table 3-1: Recommended RID Standards for New Development Subbasin and Subcatchments* Highlands: NFK, EFK, CAC, COU, LMC East Renton Plateau: LKA, LKC, PSC, RHC Jurisdiction King County, Newcastle Recommendation Stream Protection Standard (Level 2): Match post- development flow durations to existing flow durations for all flows between 50% of the 2-year and the 50-year flood peaks King County, Stream Protection Standard Renton (Level 2): Match post- development flow durations to existing flow durations for all flows between 50% of the 2-year and the 50-year flood peaks May Valley: King County Stream Protection Standard (Level 2): Match post- development flow durations to existing flow durations for all flows between 50% of the 2-year and the 50-year flood peaks CFO, MVM, MVL Highlands, May Valley: NFK, EFK,CFD Lower Basin: WT4, LBU Lower Basin: CN3, CN4, CNS, GYP, NH3, LBL, CCP Lower Basin: BNB, CNl, CN2, HCL, HCM, HCU King County Newcastle, King County Special RID Requirements (Level 4): Master Drainage Plan required for any subdivision of previously surface-mined land Lake Protection Standard (Level 3): Match post- development flow durations to existing flow durations for all flows between 50% of the 2-year and the 50-year flood peaks; and match the post- developed IOO-year peak discharge rate to the existing 100-year rate Newcastle, Stream Protection Standard Renton, King (Level 2): Match post- County development flow durations to existing flow durations for 50% of the 2- and 50-year flood peaks Renton, King Conveyance Standard County (Level 1 ): Match the post- developed peak discharge rates to the existing 2-and I 0-ycar peaks Justification Streams have potential for extreme erosion problems because of steep gradients; need for over-detention to reduce flow and sediment inputs to May Valley Need for over- detention to reduce flow and sediment inputs to May Valley Need for over- detention to reduce local flow and sediment inputs to May Valley Water quality and quantity severely impacted by mined areas; future subdivision provides opportunity for restoration Lake Boren exhibits flooding at outlet; sediment accumulation problems at inlet Streams have potential for extreme erosion problems because of steep gradients Arca is mostly built out, with previous development occurring with little or no mitigation * sec Figure 3-2 for location of specific subbasins and subcatchmcnts. Figure 3-2: Subcatchment Boundaries Map May Creek Basin Action Plan 3-9 Comments This standard is currently required by the adopted Storm Water Design Manual in King County. The City of Newcastle has also adopted the King County Manual This standard is currently required by the adopted Stom1 Water Design Manual in King County. The standard would continue to apply regardless of future annexations This standard is currently required by the adopted Storm Water Design Manual in King County Requirement applies only to land within boundaries of current and fom1er quarry operations This standard is currently required by the adopted Storm Water Design Manual in King County, and as also adopted by Newcastle 4/23/01 liiiiil Luke Wa.1hi11gto11 _.,,,... Basin Boundary ______....---. Stream c:::::::> lake Subcatchment Boundary CN2 Subcatchment Nome .. -- LBU lGYP I LJ ,,,, ~· \ ~ llor:,1 '" v--1 ,_ NH3 I -; , _ ,.,,,,,,, \ --I ,;-, ,,/ , ,, I -" •d -< I \ I ' LBL j-I WT 4 -·>-' 1'' e,\":.. <I::, I ,1 -_., ,, I / \ I ' \ G~f . -/' CN4' I -' I --~'~4\ V ----, c_N3 ,-, '-.._),,, \ CCP I . C't \ . ./ 1 -' 1 • CN5 I ,.,,. ,~' I / J .,- ~ -. ' --' ,.,i;:" ,.,,_ I ' .,,..,,. ~ .., \/-.... ..: <' ,:: -HCM ., _\ ; / ~.... (' \ -~' ,,'!' ' ~ \ I ' \ \ ' \ I \ LMC ,- ~\~'-'h ·c/· ,,,,;. ' -/ / -~~ .... rQ4.,,,_J, <-':'" ... ,:-_;_ MVL PSC \ ., ., ., -\l_' I \ Figure 3-2 Subca~chmen~ Boundaries Map May Creek Basin CAC ;: \\ 0 CFD -, / \ / I I I I I },. I / ' \ \ I NFK ,t " ~\ N * 0 1/2 1 Mile October 1998 9810 3-2 Subca1chme11t5 WG -llilll ----lllilliil -liiill lilliiRI l!!!!!!m l!!!!!l lil!i'!l I!!!!!!!) l!!!!!!ll ------- Lake RENTON CJ R/D Area-level I CJ R/D Area-level 2 CJ R/D Area-level 3 @ R/D Area-level 4 ._,,,,..... Basin Boundary • -' ... Subarea Boundary ~ Stream & Stream Number = Lake 5-0 =:::i Weiand & We~and Number --~-.. Jurisdictional Boundaries C:J Incorporated Areas Outside Basin --- I i i_ _______ j ..... ___ __ " \ o.,C'"'"" ,1 B;, t '59 '53 r/'re,:J,; '---i, ,, r'" / i N * 0 1/2 October 1998 ~., 1 Mile -------- Figure 3-3 Retention/Detention Standards Map May Creek Basin HIGHLANDS c-,,~~,,,~ •• / \ ~ ---~ 111111 9810 3-2mayRETENTIONdetention WG I I I I I I I I I I I I I I I I I I 2. Develop Basin Stewardship and Community Coordination and Participation through the Creation of a May Creek Basin Steward Implementing Agencies: King County Water and Land Resources Division, City of Renton, City of Newcastle Cost: Approximately $60,000 per year, basinwide Recommendation: Establish a May Creek Basin Steward to work cooperatively with residents and businesses in May Valley and with King County pennitting and technical staff in the implementation of Basin Action Plan recommendations, to coordinate volunteer and educational activities in the basin for all three jurisdictions, and to be an ongoing, single point of contact for the county to work with residents, businesses, the three jurisdictions, and other key stakeholders active in the basin. Discussion: King County values working with a community to take care of a place, and has established a very successful Basin Steward program in basins across the County. The program often works through cost-sharing arrangements with cities in the basins, who pay for services provided in their areas. This provides the advantage of having a dedicated staffperson familiar with the entire drainage basin and how its water resource issues interrelate. The Basin Steward develops specialized skills and knowledge by working with residents, businesses, and the different government agencies active in the basin. The successful implementation of many of this plan's recommended actions depends on King County having a Basin Steward to work closely with individual property owners in May Valley. Work program activities to be performed by the basin steward primarily will include: 0 working with permit agencies, King County Parks, and property owners currently pursuing reclamation of the former Sunset Quarry site as described in Recommendation #6 (Restore Flows Diverted from Tributary 0294 back into Tibbetts Creek); 0 acting as a liaison between King County technical staff pursuing implementation of basin plan capital projects and the communities in which they are to be implemented; • working with basin residents to expedite information requests, permitting efforts, and technical assistance to guide volunteer-based efforts; 0 working with landowners to inform them when an observed activity on private property could potentially constitute a violation ofland use regulations. The basin steward does not have enforcement authority for King County Sensitive Areas Ordinance or other regulations, but will act as a source of information, coordination, or assistance as requested by landowners who wish to remedy potential or cited code violations on their property; 0 responding to citizen concerns about basin activities or conditions that may be affecting private property or aquatic resources in the basin; a providing information and application assistance to basin residents and organizations regarding potential sources of grant funding for community-led projects; 0 working with property owners to encourage the development of Farm Management Plans and participation in incentive-based programs such as the Public Benefit Rating System. May Creek Basin Action Plan 3-13 4/23/01 Renton and Newcastle also have expressed some interest in the part-time services of a Basin Steward, particularly to coordinate volunteer activities, undertake public education regarding surface and groundwater protection and the connection between surface and groundwater, and oversee smaller capital projects in the basin. Educational activities would focus on citizen actions that can improve the water resources of the basin. Basin steward-led activities in the basin's cities would be provided as requested and city jurisdictions would fund the cost only for services provided. 3. Establish a Monitoring Program to Determine the Effectiveness of Implemented Plan Actions Implementing Agencies: King County Water and Land Resources Division, City of Renton, City of Newcastle Cost: Generally covered within existing budgets. Recommendation: Develop and implement a monitoring program designed to help determine the effectiveness ofrecommendations in this plan. Discussion: The overall goal of a monitoring program for the May Creek Basin Action Plan should be to evaluate the effectiveness of the plan in achieving its key goals: reducing the threat of flooding in the basin; protecting and enhancing fish and wildlife habitat and water quality; reducing erosion; and preventing existing problems from worsening in the future. Monitoring activities would generally cover both long-term conditions in the basin and the effectiveness of specific projects, as shown in Table 3-2. They would be coordinated with monitoring performed in the basin by others, including community organizations, the Washington Department of Fish and Wildlife, and the Muckleshoot Indian Tribe. Monitoring in the basin may support additional goals, such as a regional response to potential listings under the ESA. The data collected should satisfy all monitoring requirements included in project permits. Overall, monitoring data should be analyzed and reported every two years, and may provide the basis for modifying Basin Action Plan recommendations. The exact schedule for monitoring activity may be affected by a jurisdiction's responsibilities to respond to ESA listings. This may entail a shorter time frame before initiation of information gathering, analysis, and reporting. The three jurisdictions should develop and oversee the monitoring program together, though each may be responsible for different parts of it. Where appropriate, volunteers will be encouraged to participate in monitoring activities, and King County's activities will be coordinated with the activities of community organizations. May Creek Basin Action Plan 3-14 4/23/01 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Table 3-2: Proiected Monitoring Program Activities Monitoring Activity Questions, Data Addressed 200 l 2002 2003 2004 2005 I. Land Use Proportions of various land uses in X X basin, percent impervious surface, etc. 2. Hydrology Baseflows; relation of flows to rainfall X X X X X 3. Water Quality Stonn and ambient data X X X X X 4. Channel Measurements/ Channel scour and sediment X X X Habitat Surveys deposition; pool/riffle ratios, canopy cover, substrate quality, etc. 5. Macroinvertebrate Species presence, abundance, and X X Sampling diversity-key measures of biotic health 6. Fish Surveys Spawners, juveniles X X X 7. Small Lakes Monitoring Water quality of Lake Kathleen, Boren X X X X X 8. Project Monitoring Effectiveness of capital projects X X X X X 9. Analysis and Reeorting Summary bi-annual reeorts X X 3.2.2 May Valley Subarea 4. Provide Cost-sharing and Technical Assistance for Flood Protection in May Valley Implementing Agency: King County Department of Natural Resources Cost: $600,000+ Recommendation: Provide funding and technical assistance to address flooding problems in May Valley, prioritizing homes that are most frequently flooded and, where possible, incorporating improvements to May Creek and the valley wetland. Explore opportunities to obtain federal and state funding to help implement flood protection projects. Discussion: A great portion of May Valley lies in a natural floodplain, where flooding would occur with or without human development. Flooding has been worsened by increased runoff from development and associated clearing of surrounding forested upland areas; sedimentation of the stream channel; the growth of vegetation in the channel, reducing the creek's volume capacity and impeding its flow; and trampling of banks by livestock, which has aggravated sedimentation as well as water quality problems. Regulations have been developed to protect some of the important natural characteristics of wetlands and floodplains, placing controls on some land uses. These sensitive area regulations provide some flexibility to landowners, particularly for existing uses. A discussion of these regulations is provided in Appendix B of this document. Goals for reducing flooding under this plan are, in order of priority: (l) to eliminate significant public safety hazards ( e.g., culvert failure at the Newcastle railroad trestle embankment); (2) to May Creek Basin Action Plan 3-15 412310 I alleviate flooding of homes, businesses, sole access roads and foundations; (3) to reduce flooding of septic systems and wells; and ( 4) to reduce the financial and social burden of pasture and crop land flooding. These goals must be met without causing negative downstream impacts. Modeling of flooding in May Valley conducted as part of the Conditions Report indicates that approximately seven homes and at least one business are within the 100-year floodplain. Additionally, extensive flooding of pastures occurs in May Valley during much of the year. Flood velocities and depths are generally low, so they do not threaten public safety in most places, but the flooding of wells and septic systems do pose a health concern for many residents. Flooding in May Valley has disproportionately affected several landowners. This plan recommends a comprehensive approach that includes elements which: address surface water problems for May Valley residents; preserve the floodplain, wetland, and in-stream habitat of the valley; and protect downstream residents from flooding and ravine erosion. This recommendation calls for working with landowners to address flooding problems in May Valley, prioritizing homes that are most frequently flooded, and incorporating conveyance and habitat improvements to May Creek and the valley wetland where possible. Components of this recommendation include: on-site drainage improvements, flood-proofing of homes, voluntary home buyouts, construction of off-channel flood storage ponds, removal of old fill in the floodplain, wetland and stream buffer restoration, and other actions developed in cooperation with landowners and regulators. Previous analyses indicated that six remaining sites in May Valley are most affected by flooding. King County should work with these landowners first to determine specific needs and provide the appropriate assistance to solve flooding problems. An earlier version of this recommendation emphasized flood-proofing homes in the floodplain through home elevation. Recent investigations of the eight specific sites identified as most affected by flooding, as well as discussions with the landowners, have revealed that home elevation is not typically a workable solution. In some cases, the finished floor elevation is already above the 100-year flood elevation, though the land is not. Flooding remains a problem for these citizens; septic tanks are inundated each winter, access to dwellings is cut off, and outbuildings are flooded. In other cases, the flooded living space is below grade and the problem is the result of groundwater intrusion. In situations where high-priority flooding problems cannot feasibly be resolved by site-specific measures, home buyout is an option. Property would be purchased only from willing sellers, and all acquisitions would be voluntary. On a project specific basis, relocation assistance may be available based on applicable state and federal laws and guidelines. Land acquired under this recommendation would be managed to minimize valley flooding and maximize conveyance and habitat. The acquired land would be maintained as open space in perpetuity. Project selection would incorporate the input of landowners and would be based upon a number of criteria, including the severity of the problem, the likelihood of its being solved by the proposed action, the expected cost, and the value of related habitat and flood storage improvements. Project design, permitting, and construction would follow agreements with landowners. May Creek Basin Action Plan 3-16 4/23/01 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I The plan recommends that the County provide technical assistance for design, permitting and construction of projects to reduce flooding and/or enhance habitat elsewhere in the valley. Examples of such projects include removal of invasive plants and noxious weeds, maintenance of drainage ditches, and other actions developed in cooperation with property owners. This recommendation would be closely coordinated with: • Recommendation 5 (Remove Flow Obstructions from the Channel of May Creek in May Valley) • King County's Small Habitat Restoration Program • King County's Neighborhood Drainage Assistance Program. The $600,000 of current funding for this recommendation should result in an implementation program that reaches as many residents as possible to reduce flooding problems on their sites. Additional funding for some of these measures could be available through additional King County appropriations, and state and federal grant programs, including programs administered by FEMA. 5. Remove Flow Obstructions from the Channel of May Creek in May Valley Implementing Entities: King County Water and Land Resources Division, valley residents, pennitting agencies Cost: Up to $350,000 for pilot projects. This cost does not include subsequent public or private costs to maintain the pilot project sites and to complete similar projects in the rest of May Valley. Recommendation: Reduce flood durations in May Valley by removing flow obstructions from May Creek channel. Types of obstructions most frequently encountered are beaver dams, stream reaches choked with vegetation, and sediment deposits. Discussion: May Valley was cleared and drained around the beginning of the last century, and has supported agricultural and residential uses ever since. Based on this history, valley residents have urged King County to acknowledge that the current alignment-indeed, the existence-of this "ditched" portion of the creek is artificial, created for the purpose of conveying both low flows and the waters of periodic flooding out of the valley. Until the 1990s, portions of the channel were maintained by landowners who removed sediment deposits and stands of choking vegetation. The May Valley subarea supports pasture and low-intensity agricultural uses, small farms, and scattered single-family residences. Currently, 31 percent of the area is in single-family low- density uses. The subarea has several floodplain areas and annual and semi-annual wetlands, forming 39 percent of the subarea (Table 3-2, May Creek Basin Current and Future Conditions Report, KCSWM, 1995). Increased stormwater flows, periodic flooding and extended ponding of water, poor water quality, and impacts to fish are all well documented problems in the subarea. Analysis of past, existing, and forecast storm runoff and flooding conditions of the May Creek Basin indicate that flooding has increased significantly and will probably continue to increase as the basin is developed (KCSWM, 1995). May Creek Basin Action Plan 3-17 4/23/01 Local, state, and federal regulations have increasingly limited the ability of landowners to work in the stream, the adjacent wetland, and their buffers. The goal of this recommendation is to develop methods for channel clearing that would be allowable under these regulatory requirements, emphasizing those that could be implemented by valley residents in the future on a maintenance basis. This recommendation seeks to design and implement pilot channel-clearing projects, and to resolve and clarify permitting issues as they arise. Except for emergencies and certain routine maintenance activities, King County's Sensitive Areas Ordinance (SAO) generally prohibits alterations to sensitive areas like the valley channel reach of May Creek. Certain activities such as roadside and agricultural ditch maintenance and stream enhancement or restoration projects are allowed alterations within sensitive areas and can be permitted if they meet certain development standards. If an activity is not exempt from the SAO or an allowed alteration, it can be permitted only as an exception to the SAO. Public Agency and Utility Exceptions (PAUEs) and Reasonable Use Exceptions are two of the exception processes available. King County Code 2 lA.24.0508 describes the agricultural activities allowed in sensitive areas. To qualify under code, these activities must have been in existence before November 27, 1990, and repeated at least once every five years since. Salmon-bearing agricultural drainage ditches can be maintained by private property owners if sensitive area requirements (detailed in KCC 2 IA.24.370M and the associated public rules) regarding fish protection, construction timing and methods, and habitat enhancement are met. Stream enhancement and restoration projects are regulated by County Code 2 lA.24.370 and 21 A.24.380. The code requires that these projects be designed primarily to provide significant aquatic habitat elements such as channel meanders, buffer plantings and preservation, and in- channel structure in the form of woody debris. Although projects that meet these requirements may also include flood reduction features such as channel clearing if impacts are properly mitigated, flood reduction can not be the primary purpose of the project. It should still be possible under this recommendation to design small projects that meet stream enhancement or restoration standards, that also provide localized flood relief in May Valley, and that could be carried out by private property owners. The exception processes of code allow some projects to occur within sensitive areas that might otherwise be prohibited, but such projects must meet certain guidelines before they can be pem1itted as exceptions. A PAUE, for example, can only be granted to a public agency or utility. As described in KCC 21A.24.070A and the associated public rules, a PAUE proposal must not only demonstrate minimal impact to sensitive areas, but also show that there is no practical alternative action that would have less impact. Alternatives must be compared on the basis of a number of factors including cost, effectiveness, and safety in addition to environmental impact. A proposal to reduce flood damage by working in the channel in May Valley would have to be compared to other methods of reducing damage such as elevating, relocating, or removing threatened structures. Mitigation for channel, wetland, or buffer impacts would vary with each design to reflect the type, duration, and significance of the impacts at each project location. Costs for similar types of projects could therefore also vary significantly from location to location. May Creek Basin Action Plan 3-18 4/23/01 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I • I I Because a PAUE can be granted only to a public agency, pilot projects developed under such an exception would not meet this recommendation's goal of developing methods that could be duplicated by private property owners. Projects requiring a PAUE may not be acceptable on all parcels because some May Valley residents have expressed a strong wish to retain private responsibility for ongoing maintenance of their land. In addition to all other local and state regulatory requirements, the U.S. Endangered Species Act mandates that any project undertaken in May Valley must be designed and constructed to prevent the loss of listed species and to protect or enhance their habitat. Using a combination of the above approaches, Water and Land Resources Division engineers and ecologists will work with the May Creek Basin Steward, private landowners, and regional agencies to (I) identify problem sites, (2) design projects that improve the flow conveyance of the main thread of May Creek under normal conditions, (3) obtain all required permits and access easements, and ( 4) construct the pilot projects. The success of this recommendation will depend upon permit issuance, and will require cooperation and close coordination between landowners, county staff, and regulatory agencies. The long-term intent of the project is to establish the design criteria, the regulatory requirements, and the costs of projects that address channel obstructions. Where applicable, this information and experience would then be made available to all landowners in May Valley to enable them to build and maintain similar projects on their land as needed. Cooperation between all streamside landowners in the valley will be required if a single thread of May Creek that flows freely through the entire valley is to be established and maintained. These projects would differ from a comprehensive dredge of the May Creek channel in that: (I) obstructions would be addressed on a site by site basis, and (2) the overall stream channel dimensions would not be significantly enlarged. It is not expected that removing channel obstructions would significantly change the extent of the wetland or the floodplain in May Valley, nor the regulatory protection of those areas. See Appendix H for a discussion of the project elements and implications of large-scale dredging of the May Creek channel. Specific actions to be pursued under this recommendation include: I) selecting highest priority sites for pilot projects. Criteria would include severity of existing conditions, degree of improvement expected, landowner willingness, cost, and probability of project success; 2) creating agreements with landowners outlining mutual expectations. Documents that describe long-term county or landowner commitments may be legally recorded on property titles; 3) developing design plans and specifications; 4) notifying the downstream jurisdictions of Newcastle and Renton about designs and plans, and soliciting comment from them regarding potential downstream impacts; 5) obtaining easements where necessary; 6) obtaining all permits and preparing environmental studies as required by regulatory agencies; 7) implementing the pilot projects; 8) compiling results, including design criteria, best management practices, and any mitigation required to address channel obstructions; May Creek Basin Action Plan 3-19 412310 I 9) providing information to individual landowners to enable them to undertake similar projects on their own land; 10) disseminating the information to the public and, through the basin steward, providing ongoing advice and support. Removing these blockages is not expected to affect the extent of flooding during those times when storms cause May Creek to rise over its banks. As discussed above, minimizing and mitigating for adverse impacts to protected stream and wetland habitat would be required by permitting agencies to compensate for any adverse downstream impacts that result from this recommendation. One element of the pilot project work would be to analyze the extent of potential downstream erosion damage resulting from flood storage loss due to the removal of localized obstructions, and to implement the appropriate mitigation. Because the ultimate goal is to enable landowners to maintain their own properties, strong preference should be given to on- site compensation, rather than regional retention/detention. This recommendation would include provisions for long-term maintenance and protection of riparian habitat and open space in May Valley through coordination with such tools as Farm Management Plans and participation in tax incentive programs, such as the King County Public Benefit Rating System. 6. Restore Flows Diverted from Tributary 0294 back into Tibbetts Creek Implementing Agencies: King County Water and Land Resources Division, City of Issaquah, King County Parks Department Cost: Undetermined Recommendation: Redirect flows from upper Tributary 0294, east of SR-900, back into the Tibbetts Creek basin. Discussion: According to anecdotal information from long-time May Valley residents and numerous U.S. Geological Services maps between late l 800's and 1965, at least a portion of Tributary 0294 which lies east of SR900 previously flowed into Tibbetts Creek basin to the north of the May Creek basin before approximately 1970. This tributary reach, which currently flows through the site of the former Sunset Quarry, drains a catchment area referred to as "sub-catchment zero" in the 1979 May Creek Basin Plan Technical Appendix. That document stated that, "one corrective measure to reduce flooding in the middle reach of May Creek would be to return the flow of sub-catchment zero into its natural drainage basin, Tibbetts Creek." The topography of the contributing land makes an exact estimate difficult, but it appears that this area measures approximately 200 acres. All but about 45 acres of this total is currently forested, and would remain so should it be included in the Squak Mountain Park/Natural Area. The King County Parks Department presently owns a purchase option for this property pending its state-approved mine-site reclamation. · May Creek Basin Action Plan 3-20 4/23/01 I I I I D I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Based on the Unit Area Discharge analysis presented in the May Creek Current and Future Conditions Report, it is possible to estimate a 25-year discharge from this reach of about 40 CFS, or about 1/6 of the current total discharge from the North Fork subarea. As even this relatively modest discharge contributes to the total flow and resulting flooding in May Valley, rediverting all or a portion of this discharge back into Tibbetts Creek should help reduce flood depths and durations in May Valley. As of early 2001, many legal and technical issues remain to be clarified before this recommendation can be successfully implemented. The current and/or past owners or operators of the Sunset Quarry are obligated to comply with permits issued by the King County Department of Development and Environmental Services and the Washington State Department of Natural Resources for the operation and reclamation of the site. Work under these pennits has not been completed. Any restoration work performed at this site would have to be coordinated with the approved site reclamation plans. Since the site is privately owned, any restoration work would also have to be coordinated with the property owner. Before design work can begin on this recommendation, more information must be gathered on the historical alignment of the channels under consideration, the hydrologic character of the contributing subbasin, and the quantity of flow that can safely be directed back into Tibbetts creek. Permitting will include King County grading and other "sensitive area" approvals, Hydraulic Permit Approval (HPA) from the Washington Department of Fish and Wildlife, and potentially other federally required permits related to the jurisdictions of the Army Corps of Engineers and/or the listing agencies for the Endangered Species Act. 7. Enlarge the Culvert under S.E. May Valley Road at the East Fork of May Creek Implementing Agency: King County Department of Transportation Cost: $50,000 Recommendation: Enlarge an existing culvert under S.E. May Valley Road at the East Fork of May Creek. Discussion: The stream channel up and downstream of the site where S.E. May Valley Road crosses the East Fork of May Creek is at a very high gradient. During flood events, high gradient headwater streams in the basin transport a considerable amount of sediment. These conditions pose a risk of blockage to the existing culvert under S.E. May Valley Road. Blockage of the culvert would cause the channel to overflow, potentially causing road damage. The topography and steep slope of the stream entering this culvert are such that the potential blockage of flows through it will not reduce flows downstream. However, if the culvert were to become blocked and fail, stormflows would flow through an adjacent roadside conveyance ditch, probably causing severe erosion and downstream sediment deposition in May Valley. Under this recommendation, the existing culvert would be replaced with a larger one, less likely to become blocked-improving fish passage and reducing the chance of overflow, soil erosion, and sediment deposition in May Valley. May Creek Basin Action Plan 3-21 4/23/0 I 8. Protect Habitat at the Confluence of May Creek and Its Tributary Streams Implementing Agency: King County Water and Land Resources Division Cost: $25,000+ Recommendation: Protect high quality spawning areas from siltation through the placement of large woody debris or rock stabilization structures upstream of these areas. Discussion: Many tributaries to May Creek form deltas at their confluence with the creek. These areas represent the best remaining spawning grounds in the basin for returning coho salmon and cutthroat trout. This recommendation would protect these areas from increasing problems resulting from the delivery of fine sediments, which can reduce the quality of spawning habitats by silting instream gravels. Clean gravels are critical to successful salmon spawning. Tributary 0291A may represent a logical starting place for application of this approach. The channel of this tributary is downcutting and eroding and, without restoration, will continue to do so, thereby increasing sediment delivery downstream and into May Creek. The Conditions Report identified the mouth of Tributary 029 l A as a Locally Significant Resource Area (LSRA). LSRAs have aquatic habitat value and provide important areas for plants and wildlife. The mouth of Tributary 029 l A is known to be the site of cutthroat trout and coho salmon spawning. Data collection undertaken during development of the Conditions Report show that this confluence is one of the valley's most productive areas. This pilot project or another similar one will be selected for implementation through coordination with the Muckleshoot Indian Tribe and the WDFW for possible funding through King County's Small Habitat Restoration Program (SHRP). For the chosen stream, this recommendation would provide large woody debris, rock, and other onsite erosion-control measures above the delta to improve stream stability and habitat conditions. This approach will have the added benefit of reducing sediment delivery to the flood-prone May Valley. Measures such as this are needed elsewhere in the valley, and this approach could serve as a pilot project for similar efforts on other important tributaries in the future. 3.2.3 Lower Basin Subarea 9. Work Cooperatively to Protect the City of Renton Drinking Water Supply Implementing Agencies: City of Renton, King County Water and Land Resources Division, City of Newcastle Cost: No direct public cost Recommendation: Work cooperatively to implement the City of Renton's Wellhead Protection Program in the May Creek basin. Discussion: The City of Renton, as a purveyor of a public water supply, is required by the Washington State Department of Health (DOH) to develop a Wellhead Protection Program (WPP). In the process of developing a WPP, the City is required to identify pollutant sources within a Wellhead Protection Area (WPA) surrounding the production wells and implement, with May Creek Basin Action Plan 3-22 4/23/01 I I I I D I I I I I I I I I Iii ll I I I I I I I I I I I I I I I I I I I I I the cooperation of agencies and the private sector, a program to protect groundwater within the WPA. The WPA consists of the area described by the 10 year time-of-groundwater-travel zone surrounding production wells. It may also include a buffer zone extending to the groundwater divide and/or containing the source area of streams that contribute recharge to the groundwater system. The City operates wells for which the WPA includes a portion of the May Creek basin. The City of Renton has been implementing aquifer protection measures for many years and plans to complete a WPP that meets DOH requirements in the near future. The cooperation of adjacent land use jurisdictions will be necessary to implement the WPP since aquifers and WP As overlap jurisdictional boundaries. 10. Facilitate Permitting for May Creek Delta Dredging Implementing Agencies: King County Water and Land Resources Division, City of Renton (in cooperation with U.S. Army Corps of Engineers, Washington State Department of Fish and Wildlife, U.S. Environmental Protection Agency, Washington Department of Ecology, National Marine Fisheries Service, and Muckleshoot Indian Tribe) Cost: Negligible Recommendation: Assist the property owner at the May Creek Delta in obtaining permits needed for future dredging of sediments from May Creek. Discussion: The Barbee Mill Company is located on the May Creek Delta, where sediment deposition occurs naturally. Increases in erosive stormflows, associated with basin clearing and land development, have increased the need for dredging to allow the mill to continue its commercial operations. While the mill owner currently has an active pennit for dredging, each permit cycle lasts only five years. Dredging will have to be undertaken more frequently in the future to maintain adequate access for the mill operation, particularly as a result of increased sediment transport as further development occurs in the basin. In the future, the mill may sell its property on the delta for a mixed-use waterfront development. In the event that the mill property on the May Creek Delta redevelops in the future, opportunities to enhance May Creek habitat and reduce the need for maintenance dredging should be explored. Although a feasibility study of this option has not been undertaken, it is possible that modifying the May Creek channel could reduce the need for maintenance dredging and provide a unique opportunity to establish an improved habitat area within the lakeshore commercial area, allowing the realization of environmental and economic benefits. Any major redevelopment project also should consider opportunities for acquisition and restoration/preservation of riparian lands adjacent to the May Creek Park system. Until funding for such a project becomes available, continued dredging is the only viable alternative for maintaining commercial operations at the mill. Such dredging has no downstream impacts, and the impacts on channel habitat are localized and minimal. This recommendation recognizes the need for dredging to continue until a long-term solution can be identified and funded. Even a long-term solution likely will include some need for ongoing maintenance dredging. Therefore, this recommendation proposes that the City of Renton continue to expedite city permits for dredging activities, and that Renton and May Creek Basin Action Plan 3-23 412310 I King County provide technical assistance to the property owner for acquisition of other necessary permits as needed and as resources allow. 11. Stabilize the Slopes at the Most Significant Erosion Sites in May Creek Canyon Related to Surface Runoff Discharges Implementing Agencies: City of Renton, King County Water and Land Resources Division Cost: $550,000 Recommendation: Implement a program of erosion-control measures at the most important surface runoff-induced erosion sites in the lower basin. Given the high cost of stabilizing these sites and the significant changes in the canyon's ravine walls due to storms during the winter of 1996-97, prioritization among several identified candidate sites will be necessary before design of these measures is begun. The highest priority sites identified at this time include Honey Creek at River Mile 0.5, and May Creek at River Mile 1.2 and River Mile 1.9. Discussion: Poorly functioning surface-water conveyance systems have caused large landslides and major localized erosion along May and Honey Creeks in several locations. This erosion has increased the amount of sediment entering these systems and reaching the May Creek Delta at Lake Washington. Because erosion at these sites is ongoing, conditions are expected to worsen unless stabilization is provided. Honey Creek is designated a LSRA from River Mile 0.0 to 0.35, and May Creek has a LSRA designation from River Mile 0.2 to 3.9. As defined by King County, LSRAs have significant aquatic habitat value and provide important areas for plants and wildlife. Both LSRAs could be affected by further erosion resulting from continuing destabilization of these sites. This recommendation would allocate funding to stabilize the two or three most important erosion problems in May and Honey Creek Canyons. After plan adoption, an interjurisdictional technical team representing King County and the City of Renton would identify the most appropriate sites for stabilization. Identification of these sites would be based upon their size, amount of contribution to the May and Honey Creek sediment problem, expected costs, feasibility of stabilization, and the cause of the erosion problem. Funds would be targeted for sites where the effects of ston11water are clearly the major contributor to ravine wall slope failure. Sites where large slides are occurring naturally would not be targeted. Project design would begin once selected sites are identified. Designed solutions are most likely to involve measures to limit the impact of surface-water runoff on these slopes to prevent aggravation of existing problems. Examples of slope problems and possible solutions include the following: o Active erosion of canyon walls at River Mile 1.2 of May Creek, where drainage and stormflow from an apartment complex have been concentrated. Chronic erosion and deposition of fine sediments into May Creek is occurring with resultant delivery of sediment to the May Creek LSRA and the mouth of May Creek. In addition, approximately 6 to 8 feet of fill is encroaching upon the edge of the canyon wall, and revegetation of the fill is inhibited by the steepness and looseness of the material. May Creek Basin Action Plan 3-24 4/23/01 I I I I D I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I A solution at this site could involve diverting the runoff, which currently flows over the valley wall, into storm drains. If diversion is not possible, directing flows into a new flexible plastic pipe down the valley wall could be attempted. A small energy dissipater and detention pond on the floodplain at the foot of the hill might be necessary as well. The slope itself could require installation of backfilled slope breakers across the face of the eroding slide, with subsequent revegetation. o At River Mile 1.9 of May Creek, an 18-inch corrugated metal pipe has separated at the joint, resulting in two slope failures that deposit sediment into the May Creek LSRA and the delta. Repair work at this site could include measures such as installing plastic pipe down the slope; slope breaks to hold soil on the steep, eroded face; and revegetation. Measures such as these would prevent future erosion and avoid delivery of coarse sediment to the creek from additional slumps, thereby improving water quality and aquatic habitat. Upon adoption of the plan, implementation will involve final selection of the most appropriate sites for stabilization, as well as design and construction of appropriate, cost-effective measures. 12. Place Large Woody Debris in May Creek in May Creek Canyon Implementing Agencies: City of Renton, City of Newcastle, King County Department of Natural Resources Cost: $200,000 -$300,000 Recommendation: Place large woody debris in key locations in May Creek Canyon to provide stream channel protection and aquatic habitat, and to reduce sediment delivery to the May Creek delta. Discussion: Most creeks in the May Creek basin lack large woody debris, an important component of healthy stream systems. This is because vegetative cover in riparian areas has been depleted through the years, reducing recruitment sources of large woody debris for these waters. Large woody debris provides part of the structure that helps hold stream channels and banks together, and it creates pools and channel complexity, which are important components of aquatic habitat. In addition, large woody debris regulates sediment transport in streams, thus reducing the magnitude of sediment deposition downstream. Although large woody debris is needed throughout the basin, this recommendation recognizes placement within the May Creek Canyon as the main priority at this time, with similar placements recommended elsewhere as funding and implementation commitments are identified. Additional large woody debris would improve aquatic habitat, reduce sediment loading downstream, and protect LSRA habitat values. Because this portion of May Creek is located within a public park, increased habitat values also could present educational and interpretive opportunities. 13. Plant Conifers throughout the Riparian Area in May Creek Canyon Implementing Agencies: City of Renton, City of Newcastle, King County Water and Land Resources Division May Creek Basin Action Plan 3-25 412310 I Cost: $25,000 Recommendation: Plant conifers along lower portions (below RM 3.9) of the creek and thin the existing deciduous understory vegetation in places to promote growth of new plantings. Discussion: Additional conifers are needed to establish the desired mix of understory vegetation along the May Creek Canyon and, over the longer tenn, to establish a forest canopy that will provide ongoing recruitment of large woody debris for the stream. Currently, an abundance of deciduous trees, mostly alder, cottonwood, and vine maple, grow along the creek. Much of this canopy is nearing maturity, and the existing understory will not provide adequate habitat structure and organic inputs to the creek. Given the existing species composition in the understory, this inadequacy will extend into the future if unaddressed. In some places, existing understory vegetation is being overrun by weedy shrubs, such as holly and blackberry, and other areas have become entirely unvegetated. These conditions have increased erosion where trees are not present to hold banks together, especially during floods. Such conditions have degraded stream habitat by increasing downstream sediment accumulations. Restoration of conifers adjacent to the creek would improve habitat conditions, stabilize streambanks, and improve the complexity and diversity of fish habitat within the creek. After they mature, the conifers would provide a source oflarge woody debris to the creek when washed into the water during storms or when downed by winds. Under this recommendation, conifers would be planted along the lower portion of May Creek within the Lower Basin Subarea, and protective measures would be taken to protect newly planted trees during their initial growing stages. This effort will include opportunities for volunteer involvement in the planting projects. 14. Improve Lake Boren Water Quality Implementing Agencies: City of Newcastle, King County Water and Land Resources Division, Coal Creek Utility District Cost: Up to $30,000 Recommendation: Expand the citizen-based water quality monitoring and stewardship program to continue collecting water quality data for the lake, improve public education regarding water quality, and begin small-scale improvement actions. Discussion: Although Lake Boren and its associated wetlands are designated LSRAs, their water quality has decreased recently as a result of runoff from urbanization and construction activity in the China Creek catchment and in areas draining directly to the lake. Sediment carried to Lake Boren by China Creek has increased seasonal cloudiness in the lake during winter, and water quality data collected between 1988 and 1992 indicated consistently high levels of fecal coliform and nutrients being discharged into the lake by China Creek. As a result, the lake has had occasional high readings of fecal coliform, and high levels of phosphorus have led to regular algae blooms. Water quality monitoring data show that Lake Boren is more sensitive to lake- level fluctuations resulting from rainfall than most King County lakes. Statistics on nutrients in the lake characterize it as a "meso-eutrophic" lake, meaning that it borders on being eutrophic or "overly productive" of algae or other undesirable vegetative conditions that impair a lake's May Creek Basin Action Plan 3-26 4/23/01 I I I I I I ii I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I health. (See Appendix F for previously collected Lake Boren volunteer monitoring data.) As residential development continues to increase around the lake and in the China Creek basin, water quality conditions are expected to worsen, threatening such increasingly popular activities as fishing, swimming, and recreation in nearby Lake Boren Park. Protective actions under this recommendation would continue the volunteer programs that have provided specific information on the lake's water quality through a citizen-based monitoring and stewardship program. The program would provide additional information on existing water quality standards as well as detailed information about stream flows and runoff entering the lake under base-flow and storm-flow conditions. This information will help form the basis for a possible lake management plan, which would require grant funding from state and local sources. The development of such a plan should receive consideration as a result of preliminary data, which suggest that a combination of in-lake and watershed actions could improve long-term prospects for the lake. A lake management plan would recommend appropriate standards for water quality treatment associated with new development. Any long-tenn plan for the lake also should promote sewer service to those lakeside residences still on septic systems, which have contributed to water quality problems in the lake, particularly when lake levels are elevated by stormflows. Lake Boren is within the Urban Growth Area; therefore, the provision of sewer service to this area would be consistent with regional planning policies. If necessary, grant funding should be sought to fund these improvements. Along with citizen involvement in monitoring lake conditions, an education program would be implemented to inform citizens about the need for septic system maintenance and best management practices (BMPs) around the lake. The estimated cost for the lake monitoring and education program project is $30,000, based upon similar programs undertaken at other lakes in King County. The City of Newcastle is also considering construction of a sediment pond upstream of the lake, along China Creek, to reduce sediment delivery to the lake. Such a project could represent an early action of a lake management plan. Subsequent long-tenn implementation of a lake management plan would probably best be undertaken through formation of a Lake Management District (LMD). An LMD is a special taxing district enacted by a vote of the residents living near the lake (typically its watershed). It would involve an annual fee for a set number of years to implement or partially fund implementation of a lake management plan. 15. Improve Boren ·Creek Fish Passage at S.E. 89th Place Implementing Agency: City of Newcastle Cost: $100,000-$150,000 Recommendation: Provide additional fish passage improvements at S.E. 89th Place to improve access to upstream areas of Boren Creek. Discussion: Several culverts in Boren Creek prevent fish access to approximately 1.7 miles of upstream habitat. Lake Boren and its associated wetlands are designated LSRAs and are adjacent to the creek. The culvert under S.E. 89th Place is a potential fish barrier during high flows or May Creek Basin Action Plan 3-27 4/23/0 I when debris collects at the intake. While such passage improvements are needed in at least two other upstream locations, funding has been identified only for improvements at the stream crossing at S.E. 89th Place in Newcastle. It is the farthest downstream of the blockages and therefore represents a logical starting point for implementation of this recommendation. Similar improvements at other locations on Boren Creek are included among this plan's secondary recommendations. Passage improvements are recommended for funding as part of the current City of Newcastle budget to upgrade the intersection ofS.E. 89th Place with Coal Creek Parkway and, thus, could be accomplished relatively soon. The proposal would include an upgraded crossing of Boren Creek, probably with a bridge or open-bottom culvert. The total cost for the upgraded intersection is estimated to be $360,000. The cost of the crossing portion of the project would be approximately $100,000 to $150,000. 16. Improve the Newcastle Railroad Embankment Outlet Implementing Agencies: City of Newcastle Cost: $70,000 Recommendation: Improve the outlet structure at the railroad embankment where water now collects and poses a hazard should the current embankment fail. Monitor the pond level and establish an emergency action plan. Discussion: The Newcastle embankment is an old railroad crossing constructed on a landfill trestle. Water collects and is impounded behind this embankment. This structure is located across Newport Hills Creek approximately 0.13 mile above the confluence with May Creek. Leaks have occurred in the outlet pipe, and seepage also takes place through the embankment fill. Although analysis of the structure has indicated that it is not in immediate danger of failure, the embankment/outlet structure poses a potential hazard under severe flood conditions that could result from outlet clogging and substantial water being backed up behind the embankment. Failure of this structure could damage a home approximately 400 feet east of the embankment as well as several homes downstream. This approach would improve the outlet structure to prevent blockage of the outlet standpipe and reduce the potential of embankment failure. It would replace the existing standpipe with a new outlet structure, install pond-level monitoring devices at the outlet, and prepare an emergency action plan for evacuation in case of a breach in the embankment. The City of Newcastle has included this project as a high priority in its SWCP and would be responsible for installing the facilities, and monitoring and implementing an action plan in case of emergencies. These measures would provide the minimum action required to prevent the embankment from failing and endangering downstream homes and property and delivering substantial quantities of sediment to LSRA habitat areas of May Creek. 3.2.4 East Renton Plateau and Highlands Subareas 17. Require Full Mitigation for Future Increases in Zoning Density in Areas Draining to May Valley May Creek Basin Action Plan 3-28 4/23/01 I I I I I I • I I I I I I I I I I I I I I I I I I I I I I I I I I I I Implementing Agencies: Metropolitan King County Council, Newcastle City Council, Renton City Council, County and City planning departments Cost: No direct public cost Recommendation: In areas of the basin draining to May Creek or any of its tributaries upstream of the Coal Creek Parkway bridge, existing zoning densities (including adopted pre-zoning for unincorporated areas to be annexed) should not be increased unless a qualified hydrologic analysis demonstrates that storrnwater runoff peaks and volumes can be fully mitigated to pre- developed conditions. Density bonuses provided under development incentive programs should not be approved for these areas. The proposed Basin Steward (Recommendation 2) shall work cooperatively with each jurisdiction and, if requested by the jurisdiction, may coordinate the technical review of mitigation designs to address future flow-related impacts. Each jurisdiction will detennine the consistency with local surface water management and development regulations and may consult the Basin Steward to assess overall impacts. Further, a proposed amendment to the 2000 update of the King County Comprehensive Plan proposes designating an area in the unincorporated King County portion of the May Creek basin as the May Valley Urban Separator. This area is in the Urban Growth Area and zoned R-1. The amendment changes the land use designation to Greenbelt/Urban Separator to recognize the sensitive features of the area. In accordance with Countywide Planning Policy LU-27, the Greenbelt/Urban Separator land use designation on this parcel, if adopted, cannot be changed to other urban uses or higher densities until the next 20-year planning cycle, which would begin in 2012. This provision applies even if the property is annexed to a city. Discussion: Zoning in the May Creek basin is a complex issue. The basin contains three jurisdictions that have control over land use decisions in distinct areas of the basin, and within these jurisdictions, a range of zoning designations exist (Figure 3-4 ). In addition, the basin is bisected by the line demarking the Urban Growth Boundary, which approximately separates the upper part of the basin, draining to May Valley, from the lower basin. The Urban Growth Boundary was moved to its existing location during deliberations of the Growth Management Planning Council, in significant part to protect the rural character of May Valley and to reduce its flooding problems. There are, however, areas that drain to the valley within the Urban Growth Boundary, which either are part of Renton or Newcastle or are anticipated to be annexed by one of the Cities (Figure 3-5). Some of these areas are already built out, but portions of them remain undeveloped and subject to future building activity. These circumstances contribute to a challenging environment for addressing the relationship between zoning and surface-water problems in the valley. The basin's jurisdictions make zoning decisions in response to a variety of circumstances, including the goals of their respective comprehensive planning processes, growth management requirements, equitable treatment of property owners, and surface-water conditions. Circumstances may become even more complex as the basin jurisdictions incorporate ESA response requirements into their zoning and land use regulations. The primary surface-water problem in May Valley is extended periods of flooding. In addition, there is especially significant erosion at the upstream end of May Canyon, just above the Coal May Creek Basin Action Plan 3-29 4/2310 I Creek Parkway bridge. Future development in upland areas will increase flows to these areas and will aggravate these conditions to some degree, even assuming implementation of this plan's recommendations to protect individual property owners and aquatic resources in the valley. Enhanced requirements for drainage facilities in upland areas (see Recommendation 1) will be of some benefit but will not be of major significance in reducing flooding for a number of reasons, including the relatively impervious till soils in much of the upland area (which limits the possibility of groundwater infiltration), the fact that smaller developments will not trigger special drainage requirements, and that RID standards focus primarily upon future development. Upland drainage requirements will reduce erosion and delay stormwater runoff from reaching the valley, but during significant floods upland runoff will still generally arrive in time to add to the valley's slow-draining floodwaters. The total· volume of upland stormwater runoff, which primarily relates to the density of upland development, will largely determine how future development in the basin affects valley flooding. Although the Basin Action Plan accepts ex1stmg zoning (including adopted pre-zoning for unincorporated areas to be annexed) in the areas draining to May Creek upstream of the Coal Creek Parkway bridge as a legitimate response to the variety of concerns affecting land use decisions, it recommends that densities in these areas be increased only if a qualified hydrologic analysis demonstrates that hydrologic impacts can be fully mitigated. This would include mitigating all flow-related impacts from development with regard to the entire range of peak flows, flow durations, storm water volumes and impacts on groundwater recharge. Properties draining to this area, whether in incorporated or unincorporated King County, should not be considered potential "receiving areas" for density bonuses, such as those that may be available through a Transfer of Density Rights program for rural forest or farmlands in King County or other possible incentive programs that may be developed in the region. 3.2.5 May Valley and Highlands Subareas 18. Reduce the Potential for Negative Water Quality Impacts Originating at the Basin's Quarry Sites Implementing Agencies: King County Department of Development and Environmental Services, King County Water and Land Resources Division, Washington Department of Ecology, Washington Department of Natural Resources Cost: Included within Recommendation 2 and current agency budgets Recommendation: Ensure that the basin's closed quarry sites are reclaimed in a technically sound manner that protects resource quality and that any future quarrying activity is undertaken in compliance with existing water quality standards. If quarries remain open, develop a strategy to provide improved enforcement, technical assistance, and/or incentives to quarry operators to improve operating practices and reclamation techniques to minimize impacts on surface-water quantity and quality. May Creek Basin Action Plan 3-30 4/23/01 I I I Ii • I I I I I I I I I I I I I I --- Lake Washington - I ,e ·•1._,, ·."'_S·i ___ : c: - Zoning Classification (DU=Dwelling Unit) ITO Residential, one DU per acre !R'4:J Residential, four DU per acre ,,TI Residential, five DU per acre m:J Residential, six DU per acre Dr] Residential, eight DU per acre cmI] Residential, 48 DU per acre O!Ll Neighborhood Business c::::t:[J Community Business [!TI] Rural Area, one DU per 5 acres Ol1iJl!l Rural Area, one DU per 10 acres 0:0 Office c::Ji[J Mineral -- ~ - \ o/ \\. - L. ____ _ ,, o?iJ.!'" ,~ ':>\ ""'11 EZ2Z] Prezoning Areas - ·-·, .. ,. ~ Area DraininC to May Creek C:=J Upstream of oal Cr Pkwy Bridge _,-Urbon Growth Boundary .--Basin Boundary ~ Stream & Stream Number -./·-Jurisdictional Boundary c::::::::> Lake --- ~ N * 0 1/2 October 1998 --- Figure 3-4 Zoning Map May Creek Basin t Mile --- / ll.!JI 9810 3-4 zoriingMAP WG !!!!!m fl!!l!.l!I @!!!!!II Lake Waslrington !!!!I!! I '~ ·•1.--,, :·,.s·1 I i;; - Zoning Classificafion (DU=Dwelling Unit) QD Residential, one DU per acre DD Residential, four DU per acre >Ts,:] Residential, five DU per acre ~ Residential, six DU per acre [J[l[] Residential, eight DU per acre CDmJ Residential, 48 DU per acre Ll![:J Neighborhood Business ~ Community Business OIB] Rural Area, one DU per 5 acres D!El!l Rural Area, one DU per 10 acres Ol:J Office c:::.!:J Mi nerol 1!!!!!!11 ----- ·-----·-··-l \ C4 o~,,,.,1c. o, ~k '" ,_, R·l E2ZZ] Prezoning Areas i ·, .. '-. .. -~;:, ~)l,.ars1, ci' .o'",; Area DroininC to May Creek c:::J Upstream of oal Cr Pkwy Bridge -./""' Urban Growth Boundary _... Basin Boundary ~ Stream & Stream Number -./·-Jurisdictional Boundary c:::::::> Lake -- N * 0 1/2 October 1998 --- Figure 3-4 Zoning Map May Creek Basin 1 Mile --- 9810 3-4 zoningMAP WG I I I I I I I I I I I I I I I I I I I Discussion: Quarry operations in the May Creek basin, as elsewhere in the County, have historically had major effects on downstream stormwater flows and water quality. The many activities associated with quarrying operations, including earthmoving, gravel extraction, materials stockpiling, and truck traffic to and from quarry sites, can contribute to discharge of turbid, sediment-laden water. Operations at the various quarries in the basin have been less intense over the last few years, primarily because most of the material worth extracting already has been removed. Several of the quarries have changed ownership during this period. One quarry is now the site of an active composting operation, and a similar proposal has been considered at another of the closed quarry sites. As quarry operations have largely ended at these sites, the primary concern regarding the effects of quarry operations on surface-water conditions has changed, with the focus becoming adequate closure of sites rather than ongoing attention to storm water management measures intended for active sites. Certain areas of concern remain on sites that have not been reclaimed. These areas should be the focus of efforts to provide technical assistance to reclamation efforts or, where necessary, the focus of enforcement of reclamation and water quality standards. Where practicable, purchase of quarry sites may also be considered as a way of ensuring long-term restoration of those sites, thereby minimizing impacts from them in downstream areas. This recommendation is intended to achieve the following goals: o Ensure that closed quarry operations are reclaimed in a technically sound and environmentally safe manner. To assist in reaching this goal, a strategy should be developed for monitoring the conditions at closed sites and the ownership of those sites, providing improved enforcement where problems arise, offering technical assistance in preparing reclamation plans, and providing incentives to quarry operators to initiate reclamation procedures. o Ensure that any ongoing quarrying operations comply with appropriate water quality standards. The proposed Basin Steward should coordinate with quarry owners and county enforcement staff to provide improved enforcement, technical assistance, and/or incentives to quarry operators to improve management practices and minimize potential impacts on surface-water quantity and quality. Additionally, the Basin Steward should assist quarry operators in continuing current practices that help achieve this objective. 3.3 SECONDARY RECOMMEND A TIO NS What follows is a prioritized listing of the secondary recommendations that were identified during plan development. Appendix D describes the methodology used to prioritize these recommendations. Implementation of these projects would be contingent upon willing property owner participation. Many of the smaller projects ideally would be implemented or assisted through volunteers who would be coordinated by the Basin Steward. The projects are presented in Table 3-3, which follows. The map letter designations in the table refer to the project locations in Figure 3-5. May Creek Basin Action Plan 3-33 4/23/01 I Table 3-3: SECONDARY RECOMMENDATION PROJECTS I Funding I Project Scale/ Sources Map Project Type Estimated (includes Letter Project Name (erimary)• Cost** grants}*** Project Descrietion A May Creek Park Forest HR M PM,R Continue to restore mixed coniferous forest I Conversion and Stream to improve stream reaches and riparian Enhancement zones along May and Honey Creeks. Continue to introduce very large organic I debris to creek channels, as is included in primary recommendation. B Purchase Reclaimed HP L OS, R Complete the purchase of the closed quarry I Quarry Area at Pacific operation at the Pacific Topsoils site on the Topsoils Site ridge dividing the May and Tibbetts Creek basins. I C Preservation of May HP L OS, R Purchase private property in the wetland Valley Wetland #5 for preservation when interest is expressed by willing sellers. Manage acquired parcels I to protect agricultural uses on adjacent properties. Includes removal of fill placed in the wetland and enhancement activities as I desirable and as may be permitted. D N.E. 31st Street Private FR M PM Private road at end ofN.E. 31st Street has Road Culvert been overtopped by previous flooding, I Improvements cutting off access to several residences. Any future development using the access bridge should be required to upgrade to l 00-ycar flood capacity. I E May Creek Park HP Multiple S to RNT, NCT, Continue to purchase lands along the May Expansion M R Creek Canyon. I Acquisitions F Boren Creek FR s PM Upgrade the bridge along the access road to Residential Access reduce the effects of flooding. Condition I Improvements any future construction permits on properties affected by Lake Boren access road flooding to require bridge upgrades. I H Gypsy Creek Drainage FR S to M NCT,PM Removal ofold road fill and culvert I Improvements followed by rcvcgetation. Excavation of fill and culvert could use hand labor. Tightline I road runoff downsloee to creek. • Project Type: HP= Habitat Preservation; HR= Habitat Restoration; FR= Flood Reduction . •• Project Scale/Estimated Cost: VS= Very Small (less than $50,000); S = Small (between $50,000 and $200,000); M = Medium (between $200,000 and $500,000); L = Large (more than $500,000). i ••• Funding Sources: WLR= King County Water and Land Resources; KCR = King County Roads Division; RNT = City of Renton; NCT = City of Newcastle; PM= Project Mitigation; OS= King County Office of Open Space; R = Regional Funding Source. I May Creek Basin Action Plan 3-34 4/23/0 l I I I I I I I I I I I I I I I I I I I I Table 3-3: SECONDARY RECOMMENDATION PROJECTS {continued) Map Letter Project Name 148th Avenue S.E. Bridge and Approach Improvements J Coal Creek Parkway Trestle Improvements K N.E. 31st Street Bridge Improvements L N.E. 31st Street Culvert Improvements M Basinwide Conifer Reforestation N May Creek Delta Restoration 0 Lake Boren Wetland (Wetland #8) Habitat Enhancement p Forest Conversion of Wetland #28 Project Type (primary)* FR FR FR FR HR HR/HP HR HR Project Scale/ Estimated Cost** L s M M M L M M Funding Sources (includes grants)*** Project Description KCR Improve this frequently flooded road's flood protection by replacing bridge to provide increased flood conveyance and decreased backwater flooding to immediate upstream properties. Design bridge for I 00- year flood flow conveyance capacity. NCT Bridge piers supporting the Coal Creek Parkway crossing of May Creek have been designated "scour critical." Inspect and monitor after major storms, and install channel backwatering or other protective scour counter-measures as appropriate. RNT Replace bridge to provide JOO-year capacity and reduce risk of structural failure from stream erosion. Renton has applied for federal assistance. RNT Upgrade undersized culvert along N.E. 31st Street to ensure I 00-ycar flood capacity for future conditions. Reduce the risk of structural undennining from erosion. WLR, R Aggressive tree-retention and planting program to plant high levels of coniferous forest vegetation throughout the basin for maturity in 50-to 100-year time frames. RNT, PM Preserve and restore main body of original May Creek Delta. Relocate channel to improve sediment transport. Lower delta by removing deposited fill, and replant delta and buffer to restore tree-and shrub- dominated habitats. NCT, PM Restore woody plant vegetation, relocate China Creek to a new natural channel, and incorporate gravel complexes and large woody debris in new channel. NCT, PM Thinning of woody vegetation and understory planting with native conifers. Replanting buffers with native conifers. Consider purchase for preservation. * Project Type: HP= Habitat Preservation; HR= Habitat Restoration; FR= Flood Reduction. •• Project Scale/Estimated Cost: VS= Very Small (less than $50,000); S = Small (between $50,000 and $200,000); M = Medium (between $200,000 and $500,000); L = Large (more than $500,000). ••• Funding Sources: WLR= King County Water and Land Resources; KCR = King County Roads Division; RNT = City of Renton; NCT = City of Newcastle; PM= Project Mitigation; OS= King County Office of Open Space; R = Regional Funding Source. May Creek Basin Action Plan 3-35 4/23/0 I I Table 3-3: SECONDARY RECOMMENDATION PROJECTS ( continued) I Funding I Project Scale/ Sources Map Project Type Estimated (includes Letter Project Name (erima!2'.}* Cost** srants)*** Project Descrietion Q 164th Avenue S.E. FR L KCR Improve this frequently flooded road's I Bridge and Approach flood protection by replacing bridge to Improvements provide increased flood conveyance and decreased backwater flooding to immediate I upstream properties. Design bridge for I 00- year flood flow conveyance capacity. R North Fork HR L PM Relocate portions of the creek to near I Realignment original locations, or realign to restore meanders and channel diversity. Large woody debris would be added to relocated I stream reaches, and banks would be graded to reduce slopes. s North Fork Corridor HR L PM Reduce sedimentation within stream I Habitat Conservation channel, add large woody debris, and and Enhancement restore filled wetland areas in riparian corridor. 0 T Boren Creek Fish HR M NCT,PM Provide passable fish culverts at S.E. 84th Passage Improvements Way and upgrade or remove private driveway to improve fish passage. I u Enhancement and HR M WLR,PM Cleanup of existing trash piles, replanting of Restoration of Wetland native vegetation, and restoration of filled #2 wetland areas. I V North Fork Confluence HR M PM Remove shallow layers of fill and replant Restoration disturbed area with native forest vegetation. I Added opportunity to relocate North Fork, provide gravel substrate, and restore large woody debris to channel. w North Fork Wetland HR/FR s WLR,PM Several acres of fill at the southeast end of I #75 Enhancements this wetland would be removed and restored (southeast end) with native plantings to help reduce flooding on adjacent properties. I X Restoration of Outlet at HR s PM Remove fill and plant native trees and Lake Kathleen shrubs in wetland area at north end of lake. I y Wetland #50 HR s PM Remove illegal fill to enlarge wetland, plant Restoration native vegetation in buffers and disturbed wetland areas, remove trash and spoil piles, I mar consider fencing. • Project Type: HP= Habitat Preservation; HR= Habitat Restoration; FR= Flood Reduction . •• Project Scale/Estimated Cost: VS = V cry Small (less than $50,000); S = Small (between $50,000 and $200,000); M = Medium (between $200,000 and $500,000); L = Large (more than $500,000). I ••• Funding Sources: WLR= King County Water and Land Resources; KCR = King County Roads Division; RNT = City of Renton; NCT = City of Newcastle; PM= Project Mitigation; OS= King County Office of Open Space; R = Regional Funding Source. I May Creek Basin Action Plan 3-36 4/23/0 t I I I I I I I I I I I I I I I I I I I I Table 3-3: SECONDARY RECOMMENDATION PROJECTS {continued2 Map Letter z AA BB cc DD EE FF GG Project Name Preservation of Lake Kathleen Headwaters Preservation of Wetland #7 Preservation of Wetland #36 Preservation of Wetland #47 Preservation of W ctland #41 Corridor Enhancement of Wetland #3 North Fork Wetland #75 Enhancement (north end) Restoration of Wetland #34 Project Scale/ Project Type Estimated (primary)* Cost** HP M HP/HR M HP/HR M HP/HR s HP/HR s HR S (Wetland portion VS) HR VS HR s Funding Sources (includes grants)*** Project Description OS Purchase wetland and large upland buffer for preservation. OS, PM Purchase wetland and buffers for preservation. Portions of buffer may benefit from tree plantings, and opportunities for instrcam enhancement of Boren Creek arc also present. RNT, PM Purchase wetland and surrounding buffers (may include developed land) for preservation. Enlarge wetland by demolishing existing structures, removing fill, and restoring native woody vegetation. OS,PM Purchase wetland and sizable buffer to timbered steep slopes for preservation. Alter deciduous forest and understory to encourage recruitment of conifers. NCT, PM Purchase ravine for preservation and recreation purposes. Reestablish conifers on walls of preserve. Active management of recreation activities is needed. WLR,PM Fence/bridge tributary, plant wetland/riparian area with native plants, and place large woody debris in channel in wetland area. PM Disturbed areas and adjacent agricultural lands would be planted with native woody and forest vegetation with landowner pcm1ission. May be linked to potential North Fork realignment described above. Any restoration work would be designed to protect adjacent property uses from any impacts from the restoration, including flooding. NCT, PM Remove fill areas, plant native woody vegetation in disturbed wetland and buffer areas, and remove ditches to restore wetland h drolo 1 • • Project Type: HP= Habitat Preservation; HR= Habitat Restoration; FR= Flood Reduction. •• Project Scale/Estimated Cost: VS= Very Small (less than $50,000); S = Small (between $50,000 and $200,000); M = Medium (between $200,000 and $500,000); L = Large (more than $500,000). ••• Funding Sources: WLR= King County Waler and Land Resources; KCR = King County Roads Division; RNT = City of Renton; NCT = City ofNeweastle; PM= Project Mitigation; OS= King County Office of Open Space; R = Regional Funding Source. May Creek Basin Action Plan 3-37 4/23/01 Table 3-3: SECONDARY RECOMMENDATION PROJECTS (continued) Map Letter Project Name HH Honey Creek Fish Passage Improvements II Improvements to Honey Creek, River Miles l.35 to I. 72 Project Type (primary)• HR HR Project Scale/ Estimated Cost** s L Funding Sources (includes grants)*** Project Description RNT Replace or remove culvert if existing culvert is a fish passage barrier and a Department of Fish and Wildlife permit is required as part of the Devil's Elbow lift station improvements. PM Return portions of creek to natural channel with abundant woody debris and gravel beds, restore wetland habitats and buffers associated with the channel and plant native vegetation. Direct parking lot stormwater away from stream. • Project Type: HP = Habitat Preservation; HR= Habitat Restoration; FR= Flood Reduction. u Project Scale/Estimated Cost: VS = Very Small (less than $50,000); S = Small (between $50,000 and $200,000); M = Medium (between $200,000 and $500,000); L = Large (more than $500,000). ••• Funding Sources: WLR= King County Water and Land Resources; KCR = King County Roads Division; RNT = City of Renton; NCT = City of Newcastle; PM= Project Mitigation; OS= King County Office of Open Space; R = Regional Funding Source. May Creek Basin Action Plan 3-38 4/23/01 I I I I I I I I I I I I I I I I I I ---- '"''' -- / • ',,; ,, ,, ,, -- ~ Secondary recommendations project site and letter designation ,,_,,,,..,... Basin Boundary ~ Stream & Stream Number c::=:::, Lake sos::::::) Wetland & Wetland Numbers :::.==1 Incorporated Areas ! I - i_ _______ i - :....._·-., N * 0 1/2 -,, I i i i October 1998 --- Basinwide: ® 1 Mile ------Figure 3-5 Secondary !Recommendation !Projects Location Map May Creek Basin •• 9810 3-5 )f'condary Recom WG I I I I I I I I I I I I I I I I I I 4. MANAGEMENT PROGRAM EXPECTATIONS A number of goals are associated with each of the Recommended Actions contained in Chapter 3. This chapter describes the benefits and changes that are expected to accrue as a result of pursuing the recommendations presented in the preceding chapters. 4.1 NEAR-TERM IMPROVEMENTS This discussion focuses on improvements expected to result from the measures presented as primary recommendations in the preceding chapter. A guiding principle in the development of this plan has been to focus on a set of issues of primary importance in the basin, recommend actions to address those issues, and, most importantly, identify reliable sources of funds to support undertaking those actions. As a result of this focus, at the end of the three-to-five-year implementation time frame identified for this Basin Action Plan, all of the primary recommendations should have been implemented. It is possible that several of the secondary recommendations could be in place at that time as well, depending upon the schedule for a number of major projects in the basin and the success of basin agencies in obtaining funds for these improvements. The response of federal, state, and local agencies and private interests to the listing of salmonid species under the ESA may make additional funds available for implementing a number of the actions suggested in the recommendations. Given the long-term outlook and strategy necessary to achieve species recovery, funding is reasonably likely to become available for basin priorities identified in the secondary recommendations in addition to new priorities identified for implementation beyond the five-year term that is the focus of this plan. Identification of, and coordination with, potential funding sources would be a responsibility of the Basin Steward. In considering the expected benefits of these recommendations, the near-term improvements are those most likely to be achieved through implementation of the primary recommendations. Although these measures will not resolve all the problems basin residents associate with May Creek, all the concerns identified in the Conditions Report, or all the problems likely to come to light through enforcement of the ESA, meaningful improvements are expected to occur in several significant areas, including the following: o Reduction in the frequency and duration of flooding in several areas, especially in May Valley.Residents would have an avenue for technical support and assistance for locally based flood reduction/habitat improvement projects. In addition, properties prone to chronic flooding may be acquired for pennanent flood relief to inhabitants. Quicker drawdown of flooding in May Valley will lessen health concerns and nuisances caused by private flooding. o Reduction of contributions from the May Creek basin to the factors for decline of wild native salmon stocks in the Lake Washington watershed, particularly those salmon stocks listed under the ESA. In addressing the degradation of salmon habitat resulting from activities taking place in the basin, requirements from the Clean Water Act will be addressed as well, reducing the likelihood that additional substantive regulatory action would be necessary to address water quality impacts that affect listed salmonids. Although historically the integration of water quality and BSA-related species protection concerns has not occurred, responses to species listings in Puget Sound will include such integration. Such integration May Creek Basin Action Plan 4-1 4/23/0 I should help streamline local efforts that support salmon recovery and respond to federal regulatory action. o Elimination of a potential safety hazard in the basin through improvements to the Newcastle railroad embankment outlet. Although the Conditions Report concluded that failure of the embankment is not imminent and that the potential threat to downstream homes and property is not great, the current condition of the outlet is unacceptable. This remedial action, along with implementation of the recommended monitoring plan, would prevent potential blockages of the outlet, removing the threat of failure. o Improvement in May Creek Delta conditions through a localized reduction in erosion from several discrete sites and a reduced rate of increase in sediment delivery to the mouth of May Creek. Although this reduction is an expected near-term benefit of improvement measures, the advantage over current conditions and the ability to moderate future sediment contributions will ultimately be determined by the timing of future development buildout. The acknowledgment by all permitting agencies that dredging of the delta is reasonable, through the recommended facilitation of permit acquisition, will allow dredging to continue. Prospects of proposed land use changes at May Creek Delta could create the opportunity for initiation of a major habitat restoration project at the delta. The success of such a project would largely depend on the effectiveness of proposed improvements in the upper basin. o Improved local habitat in May Creek Canyon and on at least one tributary to May Valley. Improvements to the riparian corridor will begin to ensure that habitat can remain stable over longer periods of time in the future. Critical fish passage problems would be eliminated with the result of improved upstream access to spawning and rearing habitat for a variety of fish species. o Development and implementation of Farm Management Plans for many properties in May Valley, resulting in cooperative efforts between agencies and landowners, and a reduction of nonpoint pollution. Farm Management Plans have been or are currently being prepared for some properties in the Valley. This Basin Action Plan recommends that one focus of the Basin Steward be to infonn landowners about the availability of technical assistance to develop Farm Management Plans and to assist with proper implementation of measures in the Farm Management Plans. Establishment of improved stream buffers through this approach would be of significant benefit to water quality. Increased farm production would be a secondary benefit of this approach given the dual focus of Fann Management Plans: water quality protection and farm productivity. This could significantly improve water quality conditions in the basin, particularly with regard to fecal colifonns and high stream temperatures, which now present nearly lethal conditions for salmon. o Financial incentives resulting in opportunities for property owners to retain their land as open space or in small agricultural uses. The results of such efforts are expected to help achieve and maintain a low-density, rural atmosphere in many parts of the May Creek basin, particularly along the upper basin areas of May Creek and its tributaries. May Creek Basin Action Plan 4-2 4/23/01 I I I I I I I I I I I I I I i II 'I I I I I I I I I I I I I I I • I I o An increased awareness by basin residents that their actions have impacts on all water resources, including streams, wetlands, and groundwater (and the species dependent upon them), within the basin. Through this awareness, opportunities for residents to participate in habitat improvements and monitoring should increase. Contributions of volunteers interested in improving local conditions and enhancing the future quality of life within the May Creek basin are an integral part of plan goals and objectives. Educated and active residents, working with the proposed Basin Steward, are expected to play an important role in taking advantage of many opportunities for both near-term and long-tenn improvements and protective measures for basin resources. Educational information and programs will provide residents with an increased understanding of the connections between all water resources, aquifers, and groundwater protection. Along with citizen awareness and participation in improvement programs, enforcement of existing regulations intended to protect local resources continues to be important. The Basin Steward will work with landowners to inform them when an observed activity on private property could potentially constitute a violation of land use regulations. The basin steward does not have enforcement authority for King County Sensitive Areas Ordinance or other regulations, but will act as a source of infonnation, coordination, or assistance as requested by landowners who wish to remedy potential or cited code violations on their property; . The Basin Steward will be in a position to organize educational opportunities for residents and, through ongoing contact with residents, will also be able to disseminate information about the basin's resources in less formal ways. The Cities of Renton and Newcastle will have primary responsibility for regulatory enforcement efforts in areas of the basin within their jurisdictions. The Basin Steward will act as a conduit of information to the Cities about issues in the basin, and will be available to provide educational and technical assistance under contract to the Cities at their request. 4.2 LONG-TERM IMPROVEMENTS In addition to the improvements that accrue from implementation of primary recommendations over the three-to-five year period following plan adoption, improvements will accrue over the long tem1 as a result of implementation of both the primary and secondary recommendations. Given the uncertainty of the funding mechanisms for the secondary recommendations, realizing the improvements from those projects is less certain than with the primary recommendations. Secondary recommendations are likely to be implemented concurrently with the basin development that is expected to occur under existing zoning designations. The timeline for these secondary improvements may be as long as 15 to 30 years. Through mitigation measures associated with future development, and through direct interaction between basin residents and governmental agencies (including the May Creek Basin Steward), significant changes in the character of the basin are expected to be achieved as this plan is implemented. Hazardous flooding problems in the basin will be significantly reduced, and all public and sole residential access roads will be improved to be passable under at least 25-year flow conditions. A continuous riparian corridor along the entire mainstem of May Creek will be created. Development of this riparian corridor would rely upon the use of primarily native plant species. Riparian plantings in combination with fencing, where appropriate and necessary, May Creek Basin Action Phm 4-3 4/23/01 Appendix A: Alternative Solutions Considered for May Valley Flooding Alternative Solutions In addition to the primary and secondary recommendations presented in this plan, a number of alternative approaches to solving basin problems were reviewed during preparation of the Phase 1 and Phase 2 Solutions Reports (Table A-1) in 1995 and 1996. Given the importance of May Valley flooding to residents, additional alternatives are presented in this appendix. As identifled in the table that follows, these potential solutions were considered but rejected because of the limitations identified. Table A-I: Alternative Floodproofing Dredging Retention/ Detention to Protect Valley ALTERNATIVE APPROACHES CONSIDERED FOR MAY VALLEY FLOODING Description A. Floodproof 7-9 homes Minimum Cost $400,000 B. Buyout of 7-$3 million 9 homes A. Simrle channel (enlargement of existing channel) $1.3 million B. Complex $2.5 channe (low million flow with flood overflow bench) A. RID on May $2.2 Creek (460 million acre-feet) Benefits Limitations Eliminates flooding of most Does not address pasture flooding; homes; very feasibTe; little or does not fully address flooding of no habitat impacts; least outbuildings or septic systems and expensive wells; limited reach of tiasinwide funding resources Eliminates flooding of most Does not address pasture flooding, homes; very feasibTe; little or outbuildings, or septic systems and no habitat impacts wells; expensive; limited reach of basinwide funding resources Reduces nearly all pasture Low permitting feasibility because of flooding; protects most habitat impacts; does not protect all homes flooded homes and businesses; significant downstream erosion and secliment impacts; expensive; would require maintenance aredging Reduces majority of pasture flooding; protects most homes Moderate permitting feasibility; requires too much space (avg. width 70-80 feet); does not protect all flooded homes and businesses; moderate downstream impacts; expensive; would require maintenance dredging Major improvement in flows Does not address May Valley in downstream canyon; flooding volumes; does not protect minor improvement in all flooded homes and businesses; flows and volumes in May low feasibility because of number of Valley sites involved and habitat concerns; ex ensive B. RID on May Creek and tributaries (600 acre-feet) $13 million Improvement in flows in Does not address May Valley May Valley and downstream flooding volumes; does not protect canyon; eliminates most all flooded homes and businesses; flooding of homes and low feasibility because of number of businesses sites involved and habitat concerns; extremely expensive Bypass Pipeline Nine-foot-$22 million Eliminates all valley diameter flooding problems Huge impact on downstream canyon unless pipe is extended to Lake Washington; low permitting feasibility due to liabitat concerns: extremery expensive pipeline to l)ypass flows to C"oal Creek Parkwa May Creek Basin Action Plan 4/23/01 I I I i I i I l l a_ [ I I I I I I I I I I I I I I I I I I I REFERENCES Foster Wheeler Environmental Corporation, 1995. May Creek Basin Phase I Solutions Analysis. Prepared for King County Department of Public Works and City of Renton Surface Water Utility, November 1995. Bellevue, Washington. Foster Wheeler Environmental Corporation, 1996. May Creek Basin Phase 2 Solutions Analysis. Prepared for King County Department of Public Works and City of Renton Surface Water Utility, May 1996. Bellevue, Washington. King County, 1990. King County Surface Water Design Manual. King County Surface Water Management Division. Seattle, Washington. King County, 1990. Sensitive Areas Ordinance. Department of Planning and Community Development, September 1990. Seattle, Washington. King County, 1994. King County Comprehensive Plan.. Department of Planning and Community Development. Seattle, Washington. King County, 1998. King County Surface Water Design Manual Update. King County Department of Natural Resources, Water and Land Resources Division. Seattle, Washington. King County and City of Renton, 1995. May Creek Current and Future Conditions Report. King County Surface Water Management Division and Renton Department of Public Works, August 1995. Seattle, Washington. Newcastle, City of, 1997. Newcastle Comprehensive Plan. Prepared for the City of Newcastle by the Newcastle Planning Commission, Department of Planning and Land Use Services, EARTH TECH, INC., and David Evans and Associates, June, 1997. Newcastle, Washington. Renton, City of, 1995. City of Renton Comprehensive Plan. Planning and Technical Services Department. Renton, Washington. Renton, City of, 1995. Chapter 31 (Zoning Code) of Title IV (Building Regulations). Planning and Technical Services Department. Renton, Washington. Vashon-Maury Island Land Trust, 1995. Conserving Land in King County: A Landowner's Guide. Seattle, Washington. May Creek Basin Action Plan R-1 4/23/0 I Appendix A: Alternative Solutions Considered for May Valley Flooding Alternative Solutions In addition to the primary and secondary recommendations presented in this plan, a number of alternative approaches to solving basin problems were reviewed during preparation of the Phase 1 and Phase 2 Solutions Reports (Table A-1) in 1995 and 1996. Given the importance of May Valley flooding to residents, additional alternatives are presented in this appendix. As identified in the table that follows, these potential solutions were considered but rejected because of the limitations identified. Table A-I: Alternative Floodproofing Dredging Retention/ Detention to Protect Valley ALTERNATIVE APPROACHES CONSIDERED FOR MAY VALLEY FLOODING Description A. Floodproof 7-9 homes Minimum Cost $400,000 B. Buyout of 7-$3 million 9 homes A. Simple channel (enlargement of exis1ing channel) B. Complex channel (low flow with flood overflow bench) $1.3 million $2.5 million A. RID on May $2.2 Creek ( 460 million acre-feet) Benefits Limitations Eliminates flooding of most Does not address pasture flooding; homes; very feasible; little or does not fully address flooding of no habitat impacts; least outbuildings or septic systems and expensive wells; limited reach of basinwide funding resources Eliminates flooding of most Does not address pasture flooding, homes; very feasible; little or outbuildings, or septic systems and no habitat impacts wells: expensive; limited reach of basinwide funding resources Reduces nearly all pasture flooding; protects most homes Reduces majority of pasture flooding; protects most homes Low permitting feasibility because of habitat impacts; does not protect all flooded homes and businesses; significant downstream erosion and sediment impacts; expensive; would require maintenance dredging Moderate permitting feasibility; requires too much space (avg. width 70-80 feet); does not protect all flooded homes and businesses; moderate downstream impacts; expensive: would require maintenance dredging Major improvement in flows Does not address May Valley in downstream canyon; flooding volumes; does not protect minor improvement in all flooded homes and businesses; flows and volumes in May low feasibility because of number of Valley sites involved and habitat concerns; ex ensive B. RID on May Creek and tributaries (600 acre-feet) $13 million Improvement in flows in Does not address May Valley May Valley and downstream flooding volumes; does not protect canyon: eltminates most all flooded homes and businesses; flooding of homes and low feasibility because of number of businesses sites involved and habitat concerns; Bypass Pipeline Nine-foot-$22 million Eliminates all valley diameter flooding problems extremely expensive Huge impact on downstream canyon unless pipe is extended to Lake Washington: low permitting feasibility due to liabitat concerns; extremely expensive pipeline to (!ypass flows to C'oal Creek Parkwa May Creek Basin Action Plan 4/23/01 I I I I I I I I I I I I !I I I ' I ' I Appendix B: Sensitive Areas Regulations Among a number of regulations that govern land use in May Valley, those applying to sensitive areas and floodplains have become increasingly important as development occurs there. The King County Sensitive Areas Ordinance (SAO) includes wetland classifications that apply to much of the land in May Valley. Because the valley is a natural floodplain, regulations pertaining to floodplain development also guide development there. These regulations include limitations on new land uses in the valley and are intended to protect important natural resources while also protecting residences from flooding that may occur as a result of new construction. Given the overlapping nature of these requirements, this appendix is intended to clarify these regulations and their application to May Creek. The Cities of Renton and Newcastle have adopted similar ordinances to protect sensitive areas. For the purposes of this appendix, however, the King County regulations are discussed because much of the public concern regarding buffers and provisions under these regulations has been in regard to May Valley, which lies within unincorporated King County. Wetlands The SAO defines wetlands according to the presence of appropriate hydrology, soils, and vegetation. Three types of wetlands are defined according to functional values: Class I are generally large (greater than 10 acres in size) and complex, with endangered or threatened species, or unique plant associations; Class 2 wetlands are of medium size (between 1 and 10 acres) and less diverse than Class 1, but may include unusual wildlife habitat; and Class 3 wetlands are generally small (less than I acre) with less diversity than the other two classifications, and frequently include vegetation monocultures. The ordinance requires buffers around wetlands. Generally, Class I wetlands require a 100-foot buffer; Class 2 wetlands require a 50-foot buffer; and Class 3 wetlands require a 25-foot buffer. Much of the May Valley area has been classified as Class I wetlands, primarily because of the size of the wetland area there. This classification places strong restrictions on land uses in these areas. Despite the limitations placed on development by the need for buffer areas, many current uses are not affected by these regulations. Under the present regulations, exemptions are given to existing agricultural uses where such use predates the SAO adoption in 1990, or where continuous agricultural use has occurred since then. These exemptions apply to both wetland and buffer areas. Thus, grazing within buffer areas is allowed under the agricultural use exemption. Only when new development is proposed, or a change in land use is considered, are these restrictions applied. If, for example, property under agricultural use is subdivided for the purpose of constructing homes (a new use), then that use is subject to the wetland regulations. As long as the property remains in agricultural use, the current exemption continues. Streams Streams are another sensitive area with a classification system and set of restrictions similar to those described for wetlands. Three classes of streams, Classes I through Ill, have been defined based on size and average flows. Two subclasses of Class II. moderate-sized streams, have been created to differentiate between those in which salmon or trout have been observed and those in which they have not. Buffer widths for streams vary from 100 feet for streams designated Class I and Class II with salmonids to 25 feet for Class III streams. Restricted activities within these stream buffers are similar to those for wetlands, and uses existing at the time of SAO adoption are "grandfathered," that is, allowed to continue. May Creek Basin Action Plan 4/23/01 I I I D I I I I I I I I I I I I I I I I I I I I I I I I I I In areas such as May Valley, where riparian wetlands are located adjacent to streams, restrictions for new development are governed by whichever buffer is more expansive. In May Valley, this is typically the wetland buffer because each buffer width is 100 feet. For streams surrounded by extensive agricultural use, such as that which occurs in May Valley, there is an important exception to this current use exemption. The Livestock Management Ordinance, adopted in 1993, requires a number of measures, including limiting livestock access within a portion of the defined buffer of streams or wetlands. Since December 1998, properties with livestock have been required to limit livestock access within a 50-foot buffer of Class I streams or wetlands, and replant the area with native vegetation. This required stream buffer can be reduced to 25 Feet when a Farm Management Plan has been implemented. The wetland portion or this livestock buffer requirement, however, does not apply for wetlands considered to be grazed wet meadows. Therefore, in May Valley, the SO-foot buffer applies From the edge of May Creek rather than from the delineated edge or the valley wetland. Floodplains Floodplain regulations are applied in a similar manner. There are three different regulated floodplain areas, which are associated with rivers, streams, and other waterbodies: o the Federal Emergency Management Agency (FEMA) floodway, which includes the waterbody itself and adjacent areas with fast or deep water during JOO-year flows. No new structures are allowed in this area, with the possible exception of fences or corrals that do not impede flows or take up flood storage space; o the zero-rise floodway, which extends farther from the waterbody and where new development must demonstrate that it would not raise the existing JOO-year flood elevation. New residences in this area must have a building footprint of less than 2,000 square feet and cannot impede floodwaters; the footprint of existing buildings cannot be increased; any development must also meet the requirements applied to the flood fringe; and o the flood fringe, which includes the remainder of the floodplain for JOO-year flows. New development in the flood fringe must provide compensatory flood storage: all new living structures must be constructed at least I foot above JOO-year flood levels and must meet flow-through requirements. Subdivision of land in the zero-rise floodway (including the FEMA floodway) is allowed only if 5,000 square feet of buildable area outside the floodplain would result for each lot. As with wetland regulations, existing land uses are allowed to continue. Floodplain development criteria are only applied where new development is proposed. These regulations are intended to control the types of new development allowed in order to protect existing landowners whose uses have been allowed under "grandfather" provisions in the regulations. If you have questions about how sensitive areas regulations may apply to property in unincorporated King County, please contact the Department or Development and Environmental Services at 296-6655. Summary In many areas along May Creek, these wetland, stream, and floodplain regulations overlap and properties proposed for development are required to meet all of them. In most cases, existing uses are "grandfathered" so that they are allowed to continue as long as they remain active. For example, grazing within a wetland is May Creek Basin Action Plan 4123101 allowable regardless of wetland class if the grazing is an existing use that was taking place before adoption of the SAO. The major exception to this existing use exemption pertains to uses within the immediate stream buffer, where the Livestock Management Ordinance requires that by the end of 1998 all farm animals' access to streams be limited, with (in the case of May Creek) a 50-foot vegetated buffer. Fencing is recommended to ensure buffer maintenance. Note that this buffer requirement can be reduced to 25 feet through a Farm Management Plan. This reduction is recommended for all properties within May Valley. These buffer improvements required under the Livestock Management Ordinance can be undertaken with financial assistance from several agencies, including the King Conservation District and the King County Department of Natural Resources. Further cost-sharing assistance is proposed under this plan. The requirements in the King County Sensitive Areas Ordinance described above are current as of March 2001. Discussions regarding the implementation of additional or revised regulations under the SAO are presently underway in light of King County's obligations to meet the requirements of the federally issued 4 (d) rule under the Endangered Species Act. These discussions will probably result in changes to the regulations discussed in this section. For the most current information regarding the requirements of the Sensitive Areas Ordinance, please contact the King County Department of Development and Environmental Services at 206- 296-6655. May Creek Basin Action Plan 4123101 I i I D I I I I I I I I I I I I Appendix C: Public Participation Coordination with May Creek Citizens Advisory Committee The May Creek Basin Citizens Advisory Committee (CAC) was formed to provide input from local residents and concerned citizens on problems and possible solutions in the basin. The CAC consists of nine members and two alternates and includes residents and stakeholders from areas throughout the May Creek basin, including Renton, Newcastle, and unincorporated King County. The CAC was formed specifically to participate in the May Creek basin planning process and to help develop solutions to issues of concern in cooperation with the agencies preparing this plan. The group has met throughout the planning process during the last few years, and has provided important information regarding conditions in the basin and prioritization of basin problems. The CAC discussed several of the preliminary recommendations in this plan in draft form and provided comments on the proposed approach to solving basin problems. Issues of concern identified during the development of the first draft of the plan included the following: o A major issue with local residents regarding solutions proposed for May Creek basin problems has to do with the amount of development occurring in upland areas that contribute runoff to May Valley. Residents are concerned that the density proposed for urbanizing areas is too high and that newly incorporated and annexed areas were being allowed to increase development density through zoning changes without regard to local flooding impacts. In questioning the level of development taking place, the CAC members expressed concern about the ability of the proposed May Creek Basin Action Plan to address the problems associated with growth in upland areas. o Although they support the stricter retention/detention standards proposed in this plan, members are concerned that increases in impervious surfaces created by past development and changes in zoning related to new development are causing a considerable amount of the flood problems residents are experiencing. Some mentioned that local jurisdictions were not paying for or requiring the infrastructure improvements needed to support greater levels of development. It generally was believed that many of the proposed projects in this plan would be beneficial, but would not result in overall improvement to the basin unless problems associated with upland growth rates also were resolved. o The original valley flooding recommendation, as shown at the top of Table A-1 in Part A of this Appendix, focused exclusively on floodproofing existing homes and, as a result, was questioned by some CAC members. At issue was whether the proposed flood proofing measures would benefit basin functions or provide relief to only a few individuals. The cost of this approach, given the condition and assessed value of the homes likely to be aided, was thought to be too high if the measures were applied to only seven or nine homes. It was suggested that consideration be given to whether this money might be better spent on another problem in the basin where a greater, basinwide benefit could result. Another proposal was that floodproofing be accomplished through cost-sharing with affected basin residents to allow the funds to go further. With a cost-sharing requirement, participants in this proposal would be more willing to make a commitment to maintaining their homes. o Concern was expressed about existing quarry operations and the need to better regulate associated runoff. Existing provisions for inspections and fines may not have been adequate to reduce detrimental effects of surface-water runoff from quarry operations. Penalties for violations may not be strong enough, and fines may be too low to deter quarry operators from following practices with negative impacts. May Creek Basin Action Plan 4/23/01 I I I I I I I I I I I I I fl II I I I I I I I I I I I I I I I I I I I o The amount of money devoted to the May Creek basin was considered too low when compared to other King County basins. Questions were raised about the allocation of funds from local property fees and how that money was being spent within the basin. Coordination with May Valley Environmental Council Following the plan's transmittal to the King County Council in 1998, a number of concerns were raised by members of the May Valley community, regarding the proposed recommendations in that sub-area. In 2000 the citizens of that community formed the non-profit organization, May Valley Environmental Council (MVEC) to provide a formal organized community voice to work with King County in addressing concerns about the proposed plan text and recommendations. King County staff met with MVEC and citizens in May Valley in two formal public meetings and several other informal gatherings from November 2000 through April 2001, to solicit community input for plan revisions and refinements. The community provided helpful guidance and feedback related to the text and overall tone of the plan. Numerous edits and clarifications were made to the introductory chapters of the plan as a result. MVEC also requested specific revisions to the plan recommendations which related to the May Valley sub-area. These included providing additional detail to the basin steward recommendation (#2), the monitoring program (#3), and the culvert replacement on the East Fork of May Creek (#7). As a result of coordination with MVEC, several major revisions were also made to the plan recommendations as follows: o Recommendation #I initially required forest retention and stormwater retention/detention standards in areas draining to May Valley as governed by the 1998 King County Surface Water Design Manual. The recommendation now calls for a more stringent standard, making it the strictest rural development standard in King County related to stormwater discharge. o Recommendation #4 which initially focused on elevating the worst-flooded homes in the May Valley sub- area, was expanded to include home/property buyout as a method to resolve flooding issues for Valley residents. Additional funding for this recommendation was appropriated by the King County Council in 2000, and the increased funds for this project were also updated in the plan recommendation. o Recommendation #5 which previously focused on habitat buffer improvements in May Valley was re- written to create a pilot project for low-flow channel clearing of beaver dams, sediment deposits, and reed canary grass blockages. This revised recommendation emphasizes that there are probable major permitting hurdles to implementation. o Recommendations #6 which previously recommended removal of beavers and their dams in May Valley has been incorporated in the updated Recommendation #5. Recommendation #6 has been reformulated to create a project to pursue the relocation of flows from Sunset Quarry area back into Tibbetts Creek, where they may have drained historically. King County staff will continue to coordinate closely with MVEC and the citizens of May Valley during efforts to implement elements of this plan that are to take place within that sub-area. Public Review of Draft Plan Documents The May Creek Basin Action Plan was prepared with the cooperation of local residents and has included public review during the planning process. The Draft Plan received review and input from the CAC throughout the process, and two public meetings and an open house were held to discuss the Draft Plan. These efforts have resulted in a number of clarifications in the Proposed Plan, which includes information May Creek Basin Action Plan 4/23/01 prepared in response to questions obtained though the public meetings and written comments received on the Draft Plan. A summary of issues identified through public review is presented below, along with the location in the text where these issues are addressed in the Proposed Plan. Basin Steward's Role Issues: Need to identify the Basin Steward role more clearly; duties should be expanded; creation of Basin Steward should be a higher priority. Location ofText Discussion: The Basin Steward's role is the subject of Recommendation #2 in Chapter 3. Critical Drainage Area Designation Issues: Proposed retention/detention standards in the May Creek Basin Action Plan should at least be equal to the regulations presently identified for Critical Drainage Areas. Location of Text Discussion: The retention and detention standards have been revised and are identified in Recommendation #I Chapter 3. Drinking Water Quality Issues: The May Creek Basin Action Pian should include a recommendation to protect King County, Renton, and Newcastle drinking water supplies. Location of Text Discussion: Proposed actions regarding drinking water quality are described in Recommendation #9 in Chapter 3. Education Issues: A public education program should be developed to: educate basin residents about watershed characteristics and the measures local residents can take to improve current basin conditions. Location of Text Discussion: Education will largely be a function of the proposed Basin Steward, as is discussed in recommendation #2 in Chapter 3. Enforcement Issues: How regulatory plan recommendations will be enforced after implementation; permit requirements are not being met by some basin development projects. Location of Text Discussion: Certain aspects of the enforcement issue are discussed in two primary recommendations. A monitoring plan that will involve data gathering in support of the evaluation of implemented plan actions is discussed in Recommendation #3 in Chapter 3. The proposed Basin Steward would also play a role in the enforcement of resource protection standards, as is discussed in Recommendation #2. Erosion and Sedimentation May Creek Basin Action Plan 4/23/01 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Issues: Many of the erosion and sedimentation problems in the basin are closely related to the total volume of runoff occurring in the basin. Location of Text Discussion: The plan includes a number of recommendations for improvements that would reduce specific sources of current erosion and sedimentation problems and would reduce the likelihood of such problems developing in the future. These are identified in both the Primary and Secondary Recommendation sections of Chapter 3. Specific recommendations contain suggestions for actions addressing zoning densities, RID standards for new development. slope stabilization, and dredging at the delta, among other suggestions. In particular, this plan includes a land use recommendation that would retain existing zoning densities in May Valley. Combined with strict stormwater control standards for new development and a requirement to retain forestland as development occurs, this measure would limit future increases in runoff volumes. Flooding Issues: Erosion and sedimentation problems are contributing to flooding associated with land clearing and development in upland areas; the Basin Plan needs to emphasize a system-wide approach to adequately deal with flooding problems. Location of Text Discussion: Recommendation #I referred to above in regard to erosion and sedimentation issues, is intended to address flooding related to runoff volumes in a more comprehensive manner than individual recommendations intended to deal with area-specific problems. Area specific effects of flooding, in May Valley in particular, are addressed in Recommendation #4, #5, and #6 in Chapter 3. Plan Follow-through Issues: An administrative infrastructure needs to be established in the Basin Plan to carry out the proposed recommendations. Location of Text Discussion: The program would be administered by City and County divisions responsible for surface-water quality and controls. Each of the Primary Recommendations in Chapter 3 includes the name of the implementing agency or agencies responsible for that measure. The proposed Basin Steward would work with basin residents and jurisdictions to help implement plan recommendations. An interlocal agreement between King County, Renton, and Newcastle should establish their mutual responsibilities to implement the basin plan. Forest Retention Incentives Issues: How effective will forest retention incentives be and what are the results of using similar incentives in other basins in the County; the Basin Action Plan must include a forest retention recommendation: if increased density is allowed in the basin, it will result in the loss of forest cover. Location of Text Discussion: The plan includes forest retention recommendations within the discussion of RID standards in Recommendation #1 in Chapter 3. Funding May Creek Basin Action Plan 4/23/0 I Issues: The Basin Action Plan needs to include a long-term funding source: funding for the plan is too minimal and will not result in significant improvements to the basin; the budget seems low compared to that for other basins. Location ofText Discussion: Funding for the plan is discussed in Chapter 2. Stormwater Infiltration Issues: Infiltration of stormwater in the basin should be required. Location of Text Discussion: Infiltration, where possible, is addressed in the discussion of proposed RID standards in Recommendation# 1 in Chapter 3. Plan Leadership and Guidance Issues: Without recommendations for zoning and future development densities, the Basin Action Plan will not offer sufficient guidance to address flooding problems in the basin. Location of Text Discussion: Maintaining existing zoning densities is stressed in Recommendation # 17 in Chapter 3. Recommendation #3, regarding the monitoring plan, and Recommendation #2, regarding the Basin Steward, also support the concept of ongoing action to address flooding problems in the basin. Basin Land Uses Issues: Controlling land uses in the basin is the key to addressing flooding problems and the only way to address runoff volumes; need to minimize the potential for land conversions that increase density; existing development densities in the basin, as recommended by the King County Comprehensive Plan, should be maintained. Location of Text Discussion: Maintaining existing zoning densities is stressed in Recommendation #17 in Chapter 3. Scope of the Plan Issues: The scope of the Basin Plan is limited to solutions for the magnitude of problems as they now exist. Location of Text Discussion: Chapter 4 presents an overview of the expected benefits of proposed plan recommendations, both for near-term improvements (Section 4.1) and long-term improvements (Section 4 .2). The Primary and Secondary Recommendations are also Intended to prevent existing problems from worsening in the future, and together are intended to provide a comprehensive approach to addressing problems in the basin. Water Quality Issues: Water quality problems are primarily the result of upland development and cannot be resolved only by establishing stream buffers. Location of Text Discussion: The plan contains a number of area-specific improvements that would increase local water quality. These measures are discussed in Chapter 3. Maintaining existing zoning densities, as May Creek Basin Action Plan 4/23/01 I [ii u D I I I I I I I I I I I I I I I I I I I I I I I I I I I I I stressed in Recommendation # 17, would also help limit water quality degradation resulting from future development. Recommendation #I, in regard to Rm standards in the basin, also contains measures that will help maintain or improve water quality in the basin. Mitigation Standards Issues: Mitigation measures for proposed development projects are inadequate. Regulations or standards that require mitigation will not guarantee resource protection, given that some permit violations in the basin have gone unpunished in the past. Location ofText Discussion: The proposed Basin Steward, as discussed in Recommendation #2 in Chapter 3, would serve as a point of contact for local residents when permit violations occur. Potable Water Issues: The Basin Plan has limited mention of the potential for potable water problems and needs to be more specific about programs in place to protect potable water sources. Location ofText Discussion: A number of the plan recommendations in Chapter 3 would improve local water quality, including Recommendation #I. which describes new retention/detention standards. and Recommendation #17, which stresses maintaining existing densities. This chapter also includes a recommendation to protect drinking water supplies, Recommendation #9. Recognition of Plan Preparers Issues: The Basin Plan should clearly identify Renton and King County contributors as authors of the plan and explain that Newcastle was not a full partner in providing money for the plan. Location of Text Discussion: This relationship has been clarified in Chapter 2, Section 2.1 of the plan introduction. Quarries Issues: The Basin Plan should include a recommendation to hire monitoring and enforcement staff for potential quarry operation permit violations; fees for quarry violations should be raised. Location of Text Discussion: Specific actions addressing concerns about quarry operations in the basin are included in Recommendation# 18 in Chapter 3. Retention/Detention Standards Issues: The retention/detention standards should not be less restrictive in Renton than elsewhere in the basin; will Level 2 standards in Renton be maintained after annexation; need to provide greater enforcement of retention/detention standards with higher monetary penalties for violations; four standards in the basin may be too complicated and allow loopholes for avoiding the most restrictive standards; the Basin Plan should recommend design standards for retention/detention, rather than relying upon changes in the updated SWDM. Location ofT ext Discussion: Basin RID standards are discussed in Recommendation # I in Chapter 3. May Creek Basin Action Plan 4/23/01 Septic Systems Issues: The inability of the Basin Plan to adequately address stormwater volume problems jeopardizes septic systems in the Valley; it is not realistic to propose connecting existing homes on septic systems to the Metro sewer line as it would not be feasible to provide the necessary pumping stations. Location of Text Discussion: These comments reflect that the septic system issue has two important aspects: development in the Valley and the contribution of stormflows from the upper basin. Stormflows in the Valley are in part dependent upon the density of development in the uplands that drain to the Valley. The zoning density in the areas draining to May Valley is addressed in Recommendation #17 in Chapter 3. Volunteer Activities Issues: A structured method for volunteer involvement in basin projects should be established in the Basin Action Plan. Location ofText Discussion: The proposed Basin Steward, as discussed in Recommendation #2 in Chapter 3, would serve as a point of contact for local residents interested in dedicating time to improving conditions in the basin. May Creek Basin Action Plan 4/23/01 I ' I I D I I I I I I I I I Appendix D: Ranking the Secondary Recommendations Figure 3-3 describes this plan's Secondary Recommendations. In the table the projects are shown in the order of their priority for implementation, as determined on a basinwide basis. This appendix describes the methodology used in that prioritization process. Criteria Description More than two-thirds of the possible points in this prioritization methodology are available in two major criteria: the importance of the problem addressed and the overall effectiveness of the proposed project in addressing that problem. o Importance-(1-10 scale): How important is the problem that the project addresses? The determination of the significance of the problems addressed is generally guided by the Solutions Analysis and information presented in the Conditions Report. o Effectiveness -(I -6 scale): How effective is the project as a solution to the problem? The determination of effectiveness can be affected by the size and complexity of the problem: a well- conceived and planned project can get a low Effectiveness score if it addresses only one aspect of a large, complex problem. A little less than one-third of the possible points in this methodology are available in three minor criteria that cover less critical, but important, aspects of the projects. o Feasibility-(I -3 scale): How hard will it be to undertake the project and complete it effectively? This criterion primarily accounts for the ease or difficulty of meeting permitting requirements. o Olfslte/Multiple Benefits: (-3 -+3 scale): What effect(s) -positive and/or negative -will this project have on surrounding areas and the system as a whole? o Public/Local Support -(-1 -+I): If the community is aware of this project, has the response been positive or negative? The maximum point total a project can receive using this methodology is 23 points. May Creek Basin Action Plan 4/23/01 I I I I I I I I I I I I I I I I 1!!!!!!!!11 1!!!!!1111 1111 ----------------Table D-1· RANKING THE SECONDARY RECOMMENDATIONS Map Project Name Project Description Importance Effectiveness Feasibility Offsite/ Publid TOTAL Letter (1-10) (1-6) (1-3) Multiple Local Benefits Support ( +/-3) (+/-1) A May Creek Park Forest Conver.;ion and Stream Continue to restore mixed coniferous forest to Improve stream reaches and 8 6 3 3 1 21 Enhancement riparian wnes along May and Honey Creeks. Continue to introduce very large organic debris to creek cha1mels. as is included in primary recommendation. B Purchase Reclaimed Quarry Area at Pacific Complete the purchase ofthe closed quarry operation at the Pacific 8 2 3 3 1 17 fon<niJsSlte Toosoils site on the ridJ;e dividin~ the Mav and Tibbetts Creek basins. C Preservation of Eastern Extent of May Valley Purchase wetland and a substantial buffer for preservation. Removal of fill 7 5 2 3 0 17 Wetland 15 I placed In the wetland and ertltancemt>nt activities. D N.E. 31st Street Private Road Culvert Private road at end ofN.E. 31st Street has been overtopped by previous 8 6 2 0 0 16 Improvements flooding, cuulng off access to several residences. Any future development uSing the access bridge should be required to upgrade to HX}·year flood caruic!rv E May Creek Park Expansion AcquiSttions Continue to purchase lands along May Creek Canyon. 7 4 2 2 1 16 F &ren Creek Resldentlal Access Improvements Upgrade the bridge along the acces., road to reduce the effects of flooding. Condition any future construction permits on properties affected by Lake 8 6 2 -1 0 15 Boren access-road floodinP to rl'lluire brtrh1e uoorades. G Preseivation of Western Extent of May Valley Public acquisition program to obtain and consolidate large portions of 8 3 1 3 0 15 Wetland #5 and Assoc lated Buffers Wetland #5 for long-term preseivation. Would include replanting lnrol!"ram and channel and habitat l<nnmvement oroiects. H Gypsy Creek Drainage [mprovements Removal of old road fill and culvert followed by revegetation. Excavation 6 of fill and culvert could use hand labor. Tightline road runoff downslope 6 3 0 0 15 to creek. I 148th Avenue S.E. Bridge and Approach Improve this more frequently flooded road"s flood protection by raiSlng its 8 6 2 -2 0 14 Imorovements surface and renlacino bridoe to nrovide 100--war flood caruiciTV. J Coal Creek Parkway Trest.le Improvements Bridge piers supponing the Coal Creek Parkway croSSing of May Creek 8 have been designated ·scour critical." ln5pect and monitor after major 4 3 -1 0 14 storm evems. and Install protective channel backwatering measures 35 a~onriate. K N.E. 31st Street Bridge Improvements Replace bridge to provide JOO-year capacity and reduce risk of structural 7 failure from stream erosion. Renton has aPJ lied for federal assistance. 6 2 -1 0 14 L N.E. 31st Street Culvert Improvements Upgrade undersized culvert along N.E. 31st Street to ensure 100-year flood capacity for future conditions. Reduce the risk of structural undermining 7 6 2 -1 0 14 from erosion. M Baslnwide Conifer Reforestation Aggressive tree-retention and planting program to plant high levels of coniferous forest vegetation throughout the basin for maturity ln 50-to 5 4 3 1 1 14 lOO-vear time l'rames. N May Creek Delta Restoration Preserve and resrnre main body of original May Creek Delta. Relocate 7 channel to improve sediment transport. Lower delta by removing 2 1 2 1 13 deposited !ill. and replant delta and buffer to restore tree-and shrub· dominated habitats 0 Lake Boren Wetland (Wetland 18) Habitat Restore .... ooc1y plant vegetation. relocate China Creek to a new natural 5 3 1 3 1 13 Enhancement channel. and incorporate gravel complexes and large woody debris in new channel. p Forest Conversion of Wetland #28 lb.inning of woody vegetation and understoiy planting with native conifers. Replanting buffers with native conifers. Considel" purchase for 5 4 3 1 0 13 I nreservation Q 164th Avenue S.E. Bridge and Approach Imnrovements Improve this road"s flood protection by raising roadway surface and 6 reolacin2 brld2e to orovlde 100-vear flood caoacitv. 6 2 -2 0 12 R North Fork Realigrunent Relocate portions of the creek to near original locations, or 5 realign to restore meanders and channel diversity. Large woody 4 1 2 0 12 debris would be added to relocated stream reaches, and banks would be 2raded to reduce slo""~. s North Fork Corridor Habitat Conservation Reduce sedimentation within stream channeL add large woody 5 and Enhancement debris, and restore filled wetland areas in ri"'" ian corridor. 4 1 2 0 12 May Creek Basin Action Plan 02/22/02 table u-1: KANKING THE SECONDARY RECOMMENDATIONS /cont'd Map Project Name Project Description Importance Effectiveness Feasibility Offsite/ Publid TOTAL Letter (1-10) (1-6) (1-3) Multiple Local Benefits Support (+/-3) (+/-1) T Boren Creek Fish Passage Improvements Provide passable fish culverts at S.E. 84th Way and upgrade or 5 4 2 0 1 12 remove orivate drivewav to imorove fish =~uae. u Enhancement and Restoration of Wetland Cleanup of existing trash piles, replanting of native vegetation, 4 4 2 2 0 12 12 and restoration of filled wetland areas. V North Fork Confluence Restoration Remove shallow layers of fill and replant disturbed area wilh 5 2 2 2 0 11 native forest vegetation. Added opportunity to relocate North Fork. provide gravel substrate. and restore large woody debris to channel. w North Fork Wetland 175 Enhancements Several acres of fill at the southeast end of this wetland would be 4 2 2 3 0 11 (southeast end) removed and restored with native plantings to help reduce floodino on adjacent properties. X Restoration of Outlet at lake Kathleen Removal of fill and planting native trees and shrubs in wetland 4 4 2 0 1 11 area at north end of the lake. y Wetland #50 Restoration Remove illegal fill to enlarge wetland, plant native vegetation in 3 4 2 2 0 11 buffers and disturbed wetland areas, remove trash and spoil I oites, m,;n, consider fencirn!. z Preservation of Lake Kathleen Headwaters Purchase wetland and large upland buffer for preservation. 4 4 2 0 0 10 AA Preservation of Wetland #7 Purchase wetland and buffers for preservation. Portions of 3 4 2 1 0 10 buffer may benefit from tree plantings, and opportunities for irntream enhancement of Boren Creek are also oresent BB Preservation of Wetland #36 Purchase wetland and surrounding buffers (may include 3 4 1 2 0 10 developed land) for preservation. Enlarge v.-etland by demolishing existing structures, removing fill. and restoring native woodv Ve!!etation. cc Preservation of Wetland #47 Purchase wetland and sizable buffer to timbered steep slopes for 3 4 2 1 0 10 preservation. Alter deciduous forest and understory to encoura'1e recruitment of conifers. DD Preservation of Wetland #-41 Corridor Purchase ravine for preservation and recreation purposes. 3 4 2 1 0 10 Reestablish conifers on walls of preserve. Active management of recreation activities is needed. EE Enhancemem of Wetland f3 Fence/bridge tributary, plant wetland/riparian area wit:h native 4 2 2 1 0 9 plants, and place large woody debris in channel in wetland area. FF North Fork Wetland 1175 Enhancement Disturbed areas and adjacent agricultural lands would be 4 2 2 1 0 9 (north end) planted with native woody and forest vegetation. May be linked to nntential North Fork realignment described above. GG Restoration of Wetland 1134 Remove fill areas. plant native woody vegetation in disturbed 3 4 1 1 0 9 wetland and buffer areas, and remove ditches to restore wetland hvdrolol!V. HH Honey Creek Fish Passage Improvements Replace or remove culvert if determined to be a fish passage barrier, and a Department offish and Wildlife permit is 2 4 2 -2 1 7 reouired as oart of the Devil's Elbow lift station improvements. II Improvements to Honey Creek. River Miles Return po11iorn of creek to natural channel with abundant 1 2 1 1 0 5 1.35 to 1.12 woody debris and gravel beds, restore wetland habitats and buffers associated with the ch an net and plant native vegetation. Direct oarkim1 lot storrrr,1later away from stream May Creek Basin Action Plan 02/22/02 -1 la) 11-·1 -.I liiiil liiiillil liiiii1 ----l!il!!!fil E!I lllill ~ lliiiial iiiil la) lliiil The Condiaons Report notes areas of high-quality habitat, and separates them into two categories: Regionally Significant Resource Areas (RSRAs) and Locally Significant Resource Areas (LSRAs). These areas will be given official status and receive protection through their inclusion in the adoption ordinance for this plan passed by the respective basin jurisdictions. Regionally Significant Resource Areas (RSRAs) contribute to the resource base of the entire southern Puget Sound region by virtue of exceptional species and habitat diversity and abundance, compared with aquatic and terrestrial systems of similar size and structure elsewhere in the region. RSRAs may also support rare or endangered species or communities. Although typically found together, any of the following criteria are sufficient to recognize RSRAs in the watersheds of King County: I. watershed functions are not appreciably altered from predevelopment conditions, as measured by corridor integrity, hydrologic regime, sediment movement, and water quality, or 2. the diversity and abundance of aquatic or terrestrial habitats are of consistently high quality and are well dispersed throughout the system, or 3. aquatic and terrestrial life, particularly salmonids, exhibit abundance and diversity consistent with undisturbed habitats and make a significant contribution to the regional resources of Puget Sound. Only one wetland within the May Creek basin currently qualifies as a Regionally Significant Resource Area: o Wetland 11 in the long Marsh Creek (WRIA # 08.0289) basin: This Class 2 wetland meets criteria 1 and 2 of the RSRA definition. No stream reaches in the May Creek basin currently meet the criteria for RSRA categorization. Locally Significant Resource Areas (LSRAs) also contribute to the resource base of the region, but at a lesser level of both abundance and diversity compared with RSRAs. LSRAs are, however, significant within a particular basin, providing habitat that is important for plants and animals. Because aquatic systems require adequate functioning of all elements to contribute significantly to system productivity, all of the following criteria are necessary to recognize LSRAs in the watersheds of King County: I. watershed functions have been altered by clearing and filling, but corridor integrity, hydrologic regime, sediment movement, and water quality are adequate for spawning and rearing of salmonids or for maintenance of other plant and animal species, and 2. the diversity and abundance of aquatic and riparian habitats are good but not exceptional; instability, damage, and stream alterations are evident but confined to localized sites, and 3. aquatic and terrestrial life, particularly salmonids, are supported at one or more species and life stages at population levels that may be low but are sustainable. May Creek Basin Action Plan 4/23/01 I I I I I I I I I I Ii ll i I I I I I I I I I I I I I I I 'I I • • The May Creek basin contains some of the best remaining habitat among the smaller Lake Washington tributary systems, and within this habitat is one RSRA as identified in the Conditions Report. The basin also contains numerous areas that have been categorized as LSRAs and contains other areas that may be categorized as such in the future. Several stream reaches and wetlands within the May Creek basin currently qualify as Locally Significant Resource Areas: Stream Reach LSRAs: o May Creek Mains/em (WRIA # 08.0282): River Mile (RM) 0.2 to 3.9 o Honey Creek (WRIA # 08.0285): RM 0.0 to 0.4 o Boren Creek (WRIA # 08.0287): RM 0.0 to 0.48 o Unnamed Tributary (WRIA # 08. 0291 A): RM 0.09 to 0.14 o Country Creek (WRIA # 08.0292): RM 0.09 to O. l 4 o North Fork May Creek (WRIA # 08.294): 0.4 to l .O Wetland LSRAs: o Wetland 5 in the Mains/em May Creek and South Fork May Creek (WR/A # 08.0282) basin: A Class l wetland comprising a 20-to 30-acre conifer forest remnant east of SR-900 and south of SE May Valley Road only o Wetlands 38,39, and 40 in the Honey Creek (WRIA # 08.0285) and the May Creek Mains/em (WRIA # 08.0282) basins o Wetland 1 in the lake Kathleen basin: A Class l wetland o Wetland 9 in the Gypsy Creek (WRIA # 08.0284) basin o Wetland 8 in the China/Boren Creek (WRIA # 08.0287) basin: A Class I wetland o Wetland 4 in the China/Boren Creek (WR!A # 08.0287) basin o Wetland 2 in the unnamed tributary (WR!A # 08. 0291 A) basin: A Class I wetland o Wetland 13 in the North Fork May Creek (WR!A # 08. 0294) basin: A Class l wetland Figures E-1 through E-4 provide graphic illustration of important conditions in the May Creek basin, in particular the location of the basin's RSRA and LSRAs and specific problem areas. May Creek Basin Action Plan 4/23/01 la) Lake Washington 0 0 ·"-o . ,., ~o• "'~c-\ ......,,,.-Basin Boundary .... ., .., Subarea Boundary ~ Stream & Stream Number = lake c:::=.:, Wetland '-<::::;;q. Concentrated Spawning Area @/1::;; :1 Problem Area [==1 § Locally Significant Resource Area ~ Wetland Habitat Problem 8 Stream Habitat Problem ~ Flooding Problem m Water-Quality Problem ~ Erosion Problem @ Sediment Deposition Problem la} liiiil a.] liiiiiil liiiiiiil I N * 0 1/2 1 Mile October 1998 illlil iiiiiil --111111 i!lliil Figure E-1 lower 18asin Conditions May Creek Basin 026'__,.'(0~ C;,. --,,,(J o,,1cY p ~r I liii!!!il El .c,,.eek ... ' ', _.----....... . I __ , ' -, V 0 .~" 0 0289 ~e~ \,o''i • R <t -~r'.. . ~-t., -_ -=--~ ~·-~-~ -"'.,. --\ ...: '--~,, M,.af'i:,f:? -\ .,_-~c,-,.~..._ - o\'.: ;. ~ "'<i:~"' ~ m a, le; • '> . 0 r .~ :;: ~ mi C') al -~~ 6' ... ,J ~",, . \ @.\ I \ 9810E9i"~'rsinColiiail -1 . . . ------------------- 8 I L ';e~2. P"' c<,,, <.~.-:-J, ,"' 'oq I ',-: ...,6" SE Moy 1 \:_, ., -----... ------.-,v o /J r,,. trfi'l /-------=--:=, ~ ~ I ~ I o "-"~e • .,,. ~. c-;,,_,:d. --- \, ~ .. ~~,::-:.:-. ~~~-,~ .... -'ii,< C'r,.e,f•~· :;:: 0 • "'-,, ---....... . ... fu --,, /'I·~:-::::::::: ' fi"l'il ~ -"':····:::. ' ( "' . ''·"·· ..• , ... ' ·, ...a. I , '.-. • • • ·: l,\J~'•ad,, .. ~--\" fj/, > fZ'Jr-, ~ ~-····~· =·· ' . -. .. . . ~,· .. ' . -. \ ; . "'"\ "aa,,, . . •. /;' ( -~~ \ •. ,• '-···,~ - • 1 : @@'; 'ICc,t,, '" \, , @er / " I 8~ \ ·.~.:~., ~ ,. w J / C -. .. . ... ' . --a, m ~ I \ _ "_. ... ,,\~,~.. ', '•. ........ ·~ I ,, ."''· ~~-\ • ', ' • ~ ' ••• • "•' ~ 0., /' -1 \ --~---· , • 0 •• ···,•\ ill \ lill8 , / · ., , • ;• •--. • ' 'I, •• ' 0 \ ~ I'/ -::·, fi"fil --· , . . ' ·' n . ' e, ' .. > "" ' """' .. ·· • • , •• , I ' ~ ••• "' '"~I \,_: · ~~:~?:~. :~,.... • o-~<.,, :ftr,,,u~,- @~. ' "• 0 -~" ·-.,,,"'~"-.c., '""''"'-,. "' • ..._,, I sc"''""'"'"""··i .. ·'""'"'""" .. ',, o ... , '~~""'""····""··· "·····"'····"'"···"··, --.. _ .. ' "' · , , ·-·~L ""'··•· · · •. " '"· ."'" ... " '"· .. , --~, .e ~ , ~---... ""·····-··:: ~-"'"'·:-:-,+ .•. 0 ,.. X Bas,n Baondary ".,7 'J(i 0: '~::-~:;:cl.~ ····~·_::~~:·· ~~r. , ""' · « ,,, .-d I.. .. -----, ····~ ... ;,,.. , s "'" "" '" • ----, ''"'"'··•,""·· ' -~: .:...,~ .. N-··~ !~ IA'I@ \\ m@ ~m \\~···:~{?j ,,,,0'.:.:(i) .~ . "' '\ ~· '·:-.: ... ,.. t -.-, waooa -' ' • '., ~ ,_ -· tr ted Spawn;ng Ar 11, E) ~ ;;. 0 ~ 'isl ~ • ;,:,. = ~-. ' "' """' . , ... ~"--' ' @/'""1 . ·-·--. ' @ Locally S,gn, " N CJ ~.· , W ., nd Habfot Problem·. I, ". \o '"' ., JI, . ' I H bitat Problem \ \ .,:--. ';:', 8-· . "" ""'" "'"'-.• -\ \ "' ~, '" . "' Wo• OdO " " o I ' ~ ber 1998 ~ -n Problem Octo Eros10 ..... ·tion Problem @ Sediment Depos1 Figure E-2 May Valley Conditions May Creek Basin I~ e Octobe 9810E-2MayValleyCond WG [M!lil SE ol I "1o M,,y~O/fey r., ,,, 1~ /r 1~ 0 0 "'" _,.-Basin Boundary .. ;, -Subarea Boundary ~ Stream & Stream Number = Lake C'.:;:::;) Wetland .._,C:::t Concentrated Spawning Area @/1:::::1 Problem Area CJ@ Locally Significant Resource Area -°g" Wetland Habitat Problem 8 Stream Habitat Problem @] Erosion Problem §) Flooding Problem fx) Sediment Deposition Problem Mil 1W] ~ ~ ~ o::'<ri 0 ~ \ Crtr~ '!-\\\I~ ;').'bQ - --~ N • 1/2 October 1998 ~ ~ ~-, " ··- 1 Mile ~ ~ Q 1 2 8 t!i ST ~ ~ Figure E-3 Easi Renil'on l?lail'eau Conditions ii/rS:1 May Creek Basin li®) 1;.=) ,. ,,) n®/ ./,, , -1LSl\{x) 9810 E-3East Rentoo Cond WG , __ , Im (al ----------------- ,........ C , ' ---............ , ; ' .. ; ', \ _ _. ,--, I I ,, # \ < Figure E-4 Highlands Conditions \ \ '~8 l?'fil ~ / ' ·---... * '' ,I ' /""' ~-i ' .,_,,, -I •c., ----"" ,:) @ c,, ~ .-~::~"-.. m ~ ~ I -. . 0;.;.: 1 • --'---~ l ( ',, A "~" ~ \ ~ ----"'· --.. . . 'P --' " -' •-'• • • " -. . .. . '" ---· ·-. I ,_-_-:1.,~-= ''<;;:;;,_ \:~~ , .. :.:·,s'\s\, '. . -. . "'• ,--,-. .. '·. '<\ May Creek Basin c:,'1.'y;,Q ,J,ir_<IL. cr~ek ,::; \--,~, ~!" ·1: -,' ./ ~ ",· I -&-'-\:\ , •• }}_ t.s!-, f~I • i ~ ', -" ';\-, \;. 1.:::.1 • -~- ' • > ' . ~' '·<, \o • •. 'I< ·,---", \.. l'i I A -' I~ ~-. , '----~.. "0a \ , ,-"'" • : 0 -· --\:~ \:;'~· < //Z ' i ;i~C?m = '" ~ ~~\~~\ "a \'n 8fA'I 3,., ;j,I I, '/, _. /'-• \ "" ~~ I/'-, ' ''C:• I\ 8 \ ,-' -, ] I \ -"'(..., I --~,-,1 ~ I , s ~---' - \, ~ -1~,,~ Volley O "'-"', IJ. __ c;,--\\ -----':J ----, ---=---0 ,---.... ,. 1~~ ) _.,,,-. Basin Boundary ... ,,,. -Subarea Boundary ~ Stream & Stream Number C::3 Wetland , I ------~--~~ ii ~--<" -:-~--'-~;, -, ' j ~~ ';---~:-: _, ,9'_ ----------,C--I •,c\\ ~ 0 =,,,::, __ \_, '-~---~7---, "'', ' (_ ----~~.,~,rk ~~ .!. Cl'rcj ®~ ___ <:::::::::,. Concentrated Spawning Area @/f::::l Problem Area ' ~ --= ' -~=--~-----o-?!t? --'(, i~ ~ 'S...:------'(;f'n~ ,-_ -Y '{, 1~_ C: ' ~~.o \;1:·?'\ "'"'-,"'-c::::::J @) c::::::J E!I ~ 8 @8 m ® Locally Significant Resource Area Regionally Significant Resource Area Wetland Habitat Problem Stream Habitat Problem Flooding Problem Water Oua1ity Problem Erosion Problem 4 0 112 October 1998 / '< 1 Mile . t ;. 0 -~ "e -- 9810 E-4 HighlandsCond WG I I I I I I I I I I I I I I I I I I Appendix F: Lake Boren Monitoring Data -1996 & 1997 Reports The following pages contain data pertaining to Lake Boren conditions. These data were collected and summarized for the respective 1996 through 1999 Lake Monitoring Reports as part of the Volunteer Monitoring Program administered by King County WLR. May Creek Basin Action Plan 4/23/0 I I I I I I I I I I I I I I I I I I I I Appendix G: Recommended Actions Undertaken During Plan Development Several actions that were recommended during the development of the Basin Action Plan were implemented before the drafting of this document. These actions are presented below along with a description of their current status. In addition to these actions, the basin jurisdictions have undertaken a range of other actions that comprise at least a portion of other recommendations or that are complementary to the overall goal of improving basin conditions. Recommendation: Improve the Olympic Pipeline Crossing on May Creek and Rehabilitate the Associated Fish Ladder Current Status: This project was implemented during the instream construction window in the summer of 1998. The project is being monitored for effectiveness, including its effectiveness in allowing fish to pass. Implementing Agency: Olympic Pipeline Company Cost: To be determined by Olympic Pipeline Company Recommendation: Protect exposed pipeline and improve fish passage at River Mile 3.0 of May Creek. Discussion: In the past, a fish ladder was constructed at this site as mitigation for a pipeline crossing under the streambed. When not functioning properly, the ladder caused a fish barrier in May Creek. During the winter of 1996, flooding eroded the streambed, partially exposing the pipeline so that it was in danger of failing should high flows create further erosion and turbulence. Such a failure could have released petroleum products directly to May Creek and Lake Washington. The Olympic Pipeline Company began a project during the fall of 1996 to restore the stability of the crossing. This project also ensured fish access to the upper reaches of May Creek. The Olympic Pipeline Company was scheduled to return to the site in summer 1997 to install a permanent instream structure to protect the pipeline from erosion and turbulence. Because of the early return of spawning salmon to and above the subject reach, this permitted work was postponed until summer 1998. It is essential that the implemented permanent solution ensure fish passage to areas above the project site. The estimated cost of protecting the pipeline and ensuring adequate fish passage is unknown and is dependent upon the final design solution chosen by Olympic Pipeline. This design will be subject to permit review by the City of Newcastle, the Washington State Department of Fish and Wildlife, and other agencies. Recommendation: Rehabilitate the Lake Kathleen Outlet at S.E. 134th Current Status: This project was implemented during the instream construction window in the summer of 1997. Customary post-project monitoring for project effectiveness is under way. Implementing Agency: King County Department ofTransportation Cost: $60,000 Recommendation: Replace the existing culvert with a new outlet to improve downstream conveyance. Discussion: Flooding is occurring at the north end outlet of Lake Kathleen and is expected to continue as runoff increases because of future urban development. Road overtopping occurs at approximately the five- year flow, resulting in difficult access for several homes. This recommendation would replace existing May Creek Basin Action Plan 4/23/01 culverts with an outlet that would retain most of the current retention/detention value while also preventing overlapping of the road. It also may require raising the roadway surface. If raising the roadway surface is required, the cost of the project will increase, possibly resulting in a re-prioritization of the project based upon the increased funding need. A higher retention/detention standard for Lake Kathleen was considered to prevent worsening of the problem as additional development occurs in the basin. Given the lack of new development anticipated there, it was concluded that such a standard would be ineffective. May Creek Basin Action Plan 4/23/01 I I I I I I I I I I I I I I I I I Appendix H: Dredging May Creek: Technical Summary of Alternatives Analysis During development of the May Creek Basin Pian, a number of alternatives for solving flooding in May Valley were analyzed. See Appendix A for a summary of the alternative solutions that were reviewed. This appendix presents a more detailed summary of the alternative analysis for dredging May Creek, updated as of October 2000. The conceptual scope outlined here is based on the HSPF hydrologic model developed for the May Creek Current and Future Conditions Report (King County and City ofRenton, 1995) and on subsequent Solutions Analysis reports completed by a consultant for King County (Foster Wheeler, 1995 and 1996). Analysis of past, current and probable future storm runoff and flooding conditions of the May Creek Basin indicate that flood flows have increased significantly and will likely continue to increase as the basin is developed. Dredging of a simple trapezoidal channel would result in significant degradation of aquatic and wetland habitat. If a more natural compound channel were excavated, significant aquatic and riparian damage could be minimized and some improvements to aquatic and riparian habitat could be made. Therefore, compound dredge alternatives that include habitat benefits and mitigate downstream impacts are analyzed in greater detail below. Table H-1: Frequency MAY CREEK PEAK FLOWS NEAR 164'" AVE. SE Flow (cfs) Current Future Mitigated 2-year 170 193 ID-year 285 348 25-year 350 439 100-year 461 590 The average annual flow in May Creek, as measured at l 48ffi Ave SE, is 8.6 cubic feet per second (cfs). A summary of May Creek flow data from the HSPF model is shown above in Table H-1. A dredged channel sized to convey a JO-year recurrence interval event under future mitigated conditions would require a normal flow channel 1.5 feet deep by 11 feet wide to convey typical flows, embedded in a 3.5 foot deep 61 foot wide overbank floodway to convey storm flows. The floodplain bench would be vegetated. The total average channel size would be 61 feet wide and 5 feet deep. To convey the 100-year flow, (590 cfs) the floodway would need to be 1.5 feet deeper, increasing the channel width to 73 feet. All channel sizes are averages. The actual channel design would be somewhat smaller at the upper end of the valley and larger at the downstream end. May Creek Basin Action Plan 4/23/01 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Figure H-1: TYPICAL DREDGED CHANNEL CROSS-SECTION •'• To improve aquatic habitat, the compound channel must provide habitat complexity and incorporate native vegetation, large woody debris, and backwater rearing channels. These features would increase the required channel size and therefore the land required for the project. Maintenance needs also significantly influence the design of the channelization proposal. The channel would need to be redredged and disturbed areas on the floodplain bench revegetated approximately every 20 years. The existing channel slope averages 0.14% in May Valley. Increasing the stream gradient in order to minimize sediment deposition and maintenance significantly increases the channel excavation required at the downstream end of the valley. The extra depth required ranges from 9 feet to 32 feet as the stream gradient is increased to 0.2% through 0.5%. Either size of compound channel would compromise existing road bridges at 148"' Ave. SE and 164'h Ave. SE. Replacement of these bridges is currently a secondary recommendation in the Basin Plan, and would be necessary elements of a channelization project. Insofar as a dredging project moves water more quickly out of May Valley, it will increase peak flows in the downstream reaches of May Creek, significantly aggravating an existing erosion problem in May Creek canyon. To address this problem, retention/detention (RID) facilities must be included in the project design. Several options were explored, providing varying levels of protection. Decentralized approaches, which involve multiple ponds located on the tributaries and on the mainstem of May Creek downstream of SR-900 and at l 48'h Ave. SE would require a total of 459 acre-feet ofnood storage. These ponds are designed to reduce the 25-year future mitigated peak flows to the IO-year current peak flows. A centralized RID approach, designed specifically to protect May Creek downstream of the valley, would reduce the 100-yearfuture mitigated flow (590 cfs) to the 2-year current peak flow (170 cfs). This level of protection would require siting 600 acre-feet of storage in the vicinity of 148'' Ave. SE. The Stream Protection Standard is the current applicable standard, and would require even larger storage area. Whether the RID volume required for the final design is 459 acre-feet, 600 acre-feet or more, the feasibility of siting the ponds is poor. The valley floor between SR-900, SE May Valley Road, and 148'" Ave SE is about 330 acres, and averages 1000 feet wide. A 100 acre-ft pond 4.35 feet deep would measure 1000 feet on a side and cover about 23 acres. Six such ponds on the valley floor would preclude all other land uses and eliminate wetland and riparian habitat in about one third of the valley, severely compromising the primary goals of the project. See Figure H-2 for a conceptual layout indicating the scale ofR/D facilities required. Irrespective of the siting of the ponds, dredging the creek to control flooding would severely impact May Creek Wetland 5. As identified in the 1990 King County Wetlands inventory, May May Creek Basin Action Plan 4123/01 Creek Wetland 5 is rated !(a) and covers 142 acres. It is likely that at least 100 acres of wetland would be drained by constructing the dredged channel. Wetland mitigation requirements are likely to range from 200 to 400 acres of enhanced or created wetland, preferably in the May Creek basin. Finding suitable property would be extremely difficult, and the costs of acquiring the land and finishing the wetland mitigation project would be substantial. Obtaining the required project permits from local, state, and federal agencies will be difficult and time consuming. Even though the project is designed to provide in-stream habitat benefits and to mitigate downstream impacts, unavoidable short-term impacts and wetland impacts remain. Table H-2: PERMITS REQUIRED Permit required Intent Agency DDES SEP A. with EIS Public input and alternative County analysis. DDES Clearing and Grading Protects the public from poorly planned development, and protects sensitive areas. DDES Public Agency and Utility Requires review of project Exemption alternatives, impact minimization and mitigation. WDFW State Hydraulic Project Approval Protects fish and aquatic habitat. DOE 401 Water Quality Certification Protects water quality. review USACOE Individual 404 Permit Protects integrity of waters of the Federal Possible federal EIS US, including wetlands. NMFS Concurrence with 404 Permit Protects chinook salmon and other threatened or endangered marine soecies. USFWS Concurrence with 404 Permit Protects bull trout, eagles, and other threatened or endangered freshwater and terrestrial species. Public comments, Input on Local and State permits Any group or individual may appeal Public permit appeals and approvals or file a lawsuit if they disagree with and potential the outcome of the process or feel third party that the agencies failed to lawsuits adequately enforce the Jaws. In 1996, costs of dredging the channel to control the ID-year flow, upgrading the two bridges, and constructing a 600 acre-ft retention/detention pond were estimated at $6 million or 30 million, depending on the design approach for the ponds. Maintenance of the channel was estimated at $2.8 million dollars every 20 years. Cost estimates done in 2000 that include wetland mitigation costs and updated costs for construction, permitting, and land acquisition total over $50 million, not including maintenance of the channel and RID facilities. The project also entails risks for which costs are difficult to quantify. These risks include mitigation May Creek Basin Action Plan 4/23/01 I I I I I I I I I I I I I I I I I [i I I I I I I I I I I I I I I I I I I I I negotiation, studies that may be required to complete the permitting processes, potential third-party lawsuits, and non-monetary costs of habitat damage and downstream damage in case the proposed mitigation should prove insufficient. In summary, the overall feasibility of dredging May Creek is poor, even when significant habitat features and measures to protect downstream resources and residents are incorporated into the design. The most significant barriers can be summarized as follows: I) Low technical feasibility of siting regional retention/detention ponds required to mitigate negative impacts to downstream residents and stream habitat, 2) Significant wetland damage and associated mitigation requirements, 3) Low possibility of obtaining permits required by federal, state and local agencies, 4) Cost of capital improvements, land acquisition, and maintenance. May Creek Basin Action Plan 4/23/01 :"...... 100 Acre-feet i : Flooclw..m Slorclgo Volumo i ...... J 1000 feet x 1000 feet x 4.35 feet deep -, -May Valley Subarea Boundary ---Stream = Wolland AT lEAST 600 A.CltE.fEET Of RETENllON/DETENOCIN VOLUME ARE UQUIRED AT THE LOWER END Of MAY VAUE'Y TO l'tOTECI TliE DOWNSTREAM REAOIES Of MAY CREEK. ~ i.,.. cf pfQltd>:ln b thh anolyaii reilitam lht IOOy111:11 fukJle miligoled pet& flow 1590ch)otth1t0Jl'~2~ re,::u~" intllrm1~ lbw rot&t170i::hl. Th. 1lope 0, MoyC,~~ 11 <111ly 1.-i lwl per 1000 ,..I,"' tl,o1 ,c.onc:•pl.1oldepth Pi0wr1 al o-.t f"t Q prcbably "°' r-11111, P.rmd Qll(!(l inc,eoMn If d11prli 1, d1ttr11K111Jd, May Creek Basin Action Plan May Valley R/0 Conceptual Design Minimum Flood Storage Required for Dredging Moy Creek 4/23/01 I I I I I I I I I I I I !iii ti I I I I I I I I I I I I I I I I I. I I •• May Creek lDrainage improvement Project Biological Evaluation Report for: City of Renton Planning Division FEB 1 910\l \R1 lg~ lg Il~lg IQ) Chinook Salmon and Steelhead Trout as protected under tHe Endangered Species Act May Creek, King County, Washington State Prepared for: King County Water and Land Resources Division Department of Natural Resources and Parks 20 I South Jackson Street Ste 600 Seattle, WA 98104-3856 Phone number: (206) Prepared by: Mistie Hammer King County Road Services Division February 2011 -,---~,-·---o-------·----·· LWD Large Woody Debris I I I I I I I I I I I I NOAA Fisheries NMFS RM SPCC TESC WDFW WLRD WRIA WSDNR National Oceanic & Atmospheric Administration -Fisheries Department National Marine Fisheries Service River Mile Spill Prevention, Control, and Countermeasures Temporary Erosion and Sediment Control Washington State Department of Fish and Wildlife King County Water and Land Resources Division Water Resource Inventory Area Washington State Department of Natural Resources I I I I I I I I I I I I I I I I I I I May Creek Drainage Improvement Project Bnollogical JEvaluatiol!ll Report foir: City of Renton Planning Division FEB 1 910\~ [R{ ~t\~1¥/~\Q) Chinook Salmon and Steelhead Trout as protected under tHe Endangered Species Act May Creek, King County, Washington State Prepared for: King County Water and Land Resources Division Department of Natural Resources and Parks 20 I South Jackson Street Ste 600 Seattle, WA 98104-3856 Phone number: (206) Prepared by: Mistie Hammer King County Road Services Division February 2011 I I I I I I I I I I I I I I I I I I I Acronyms BE BMP DPS EFH ESA ESU HUC LWD NOAA Fisheries NMFS RM SPCC TESC WDFW WLRD WRIA WSDNR Biological Evaluation Best Management Practices Distinct Population Segment Essential Fish Habitat Endangered Species Act of 1973 (amended 1996) Evolutionarily Significant Unit Hydrologic Unit Code Large Woody Debris National Oceanic & Atmospheric Administration -Fisheries Department National Marine Fisheries Service River Mile Spill Prevention, Control, and Countermeasures Temporary Erosion and Sediment Control Washington State Department of Fish and Wildlife King County Water and Land Resources Division Water Resource Inventory Area Washington State Department of Natural Resources I I I I I I I I I I I I I I I I I I I Table of Contents I INTRODUCTION ...................................................................................................... I 1.1 Consultation Activities ............................................................................................... I 1.2 Description of Proposed Project Action .................................................................... I 1.2.1 Description of Project Elements ................................................................. 3 1.2.2 Project Sequencing and Timeline ............................................................... 6 1.3 Impact Avoidance and Minimization Measures ........................................................ 7 Construction Equipment: ............................................................................................ 7 1.4 Action Area ................................................................................................................ 9 2 FEDERALLY LISTED FISH AND WILDLIFE SPECIES IN THE ACTION AREA .................................................................................................................................. I I 2.1 Chinook Salmon ....................................................................................................... 11 2.1.1 Critical Habitat.. ........................................................................................ 11 2.2 Steelhead Trout ........................................................................................................ 11 2.2.1 Critical Habitat. ......................................................................................... 12 3 ENVIRONMENTAL SETTING .............................................................................. 12 3.1 May Creek Basin Overview ..................................................................................... 12 3.2 Habitat Conditions at the Project Location .............................................................. 13 3.2.1 Aquatic Resources .................................................................................... 13 3.2.2 Wetlands ................................................................................................... 15 3.2.3 Geology ..................................................................................................... 15 4 EFFECTS OF ACTION ............................................................................................ 16 4.1 Direct Effects ........................................................................................................... 16 4.2 Indirect Effects ......................................................................................................... 16 4.3 5 6 Effects from Interrelated and Interdependent Actions ............................................. 18 CONCLUSIONS ....................................................................................................... 19 MAGNUSON STEVENS FISHERY CONSERVATION AND MANAGEMENT ACT. ......................................................................................................................... 21 6.1 Essential Fish Habitat Background .......................................................................... 21 6.2 Description of the Proposed Action ......................................................................... 21 6.3 Adverse Effects Essential Fish Habitat for Salmonids ............................................ 22 6.4 Essential Fish Habitat Conservation Measures ........................................................ 22 6.5 Conclusions .............................................................................................................. 22 7 REFERENCES ......................................................................................................... 23 Appendix A ....................................................................................................................... 25 Appendix B ....................................................................................................................... 28 Appendix C ....................................................................................................................... 3 7 I I I I I I I I I I I I I I I I I I I 1 INTRODUCTION 1.1 Consultation Activities No consultation with National Marine Fisheries Service (NMFS) has occurred. Species under NMFS jurisdiction were investigated through the development of a series of special studies completed as part of the project selection process, as well as by means of personal communications with local fish and wildlife authorities and a review of pertinent literature. The personal communication included conversations with Larry Fisher, Area Habitat Biologi st and Aaron Bosworth, Anadromous Fish Biologist for the Washington D e partment of Fish and Wildlife (WDFW). The literature review included: the WDFW Priority Habitats and Species database and species maps (dated October 29 , 2010); the Washington State Department of Natural Resources (WSDNR) Natural Heritage Information System, and list ofrare plants and high-quality native plant communities and wetlands in King County. 1.2 Description of Proposed Project Action The purpose of this Biological Eva luati on (BE) is to determine if the proposed action ma y affect any species listed by the NMFS . Section 7(c) of the Endangered Species Act (ESA) requires that projects with a federal nexus evalu ate and document impacts to threatened and e ndangered species and their critical habitats before funding, authorizing, or carrying out an action that may affect the species or their environment. A BE is necessary for this project because of its federal permit (from the Army Corps of E ngineers). Information on listed species and habitats known or potentially occurring in the project vicinity was provided by state and federa l agencies {Appendix A) and is s ummarized below (Table l ). Table 1: Information on Listed Species in the May Creek Project Action Area Species and Habitats Federally threatened endangered, and proposed plant species and communities Federally threatened and endangered and proposed fish s pecies Critical habitat for federally threatened and endangered s ecies Agency WDNR NMFS NMFS Data Provided No species or communities occur in the project action area. Two threatened species could occur in the project action area: 1-Puget Sound Chinook salmon ESU 2-Puget Sound steelhead trout DPS No critical habitat is present in the action area King County Department of Natural Resources and Parks , Water and Land Resources Division (WLRD), proposes to improve in-stream flow conditions along segments of May Creek. Sediment accumulation and in-stream vegetation (e .g., reed canarygrass and The project is located in unincorporated King County and the City of Renton in Sections 2 and 3 of Township 23 North, Range 5 East (47.51521 N latitude / -122.14301 W longitude) (Figure 1 ). The May Creek drainage basin is part of the Lake Washington watershed ( 61h field HUC l 71100120301). The project is located in the May Valley and construction activities will directly impact May Creek (WRIA 08.0282) and Long Marsh Creek (WRIA 08.0289). Figure t. May Creek Drainage Improvement Project Vicinity Map 2 May Creek Channel Restoration Project Projtd \ldnli,• e StudyArea Incorporated Areas Cougar Mountain Wlldland Park ~ + 1\1111"\'b 2010 U) King County 0 81 180 :JIO 610 l lO IIIIIIIIIIIIIC::::::::lllllllllllc:::::::;;:>F .. _ ...................... .. ... ,-=:=· .... ·--·---::t".:---·_......_...__.. --........... _...,..__ ......_ . ...,. .., ..... ., __ ............ --.···-... -... , ........... _ ............. ..... ...... _.._......,....,.__.__,. .............. -................. ... ••---•M ....... ..._. .... ... ............. --........ ...... ----.. -· .... ~ I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 1.2.1 Description of Project Elements King County's Water and Land Resources Division proposes to improve in-stream flow conditions along segments of May Creek in May Valley between approximately River Mile 4 .3 and 4 .9. This project proposal consists of three components: vegetation removal, sediment removal , and stream/wetland mitigation. The vegetation and sediment removal will negatively impact existing in-stream fish habitat, so mitigation has been proposed to offset these impacts. The mitigation is also designed to improve the longevity of the project by decreasing the opportunity for channel obstructions to form in the future. A temporary erosion and sediment control (TESC) plan will be implemented. TESC measures will be installed, inspected, and maintained throughout construction as determined by the plan. Contro l measures will be installed and in place prior to ground- disturbing activities. All clearing limits, staging area perimeters, and site boundaries will be flagged and/or fenced. 1.2.1.1 Vegetation Removal The first component of the project includes removal of approximately 2,550 linear feet of flow obstructing in-stream vegetation and debris from specific reaches where it is choking the channel creating a backwater effect. Water trapped behind these channel constrictions result in extended periods of flooding on adjacent properties during storm events . invasive reed canarygrass is the dominant vegetation that will be removed from the channel and banks. In addition, willows located in multiple locations throughout the project area, are currently growing in the middle of the channel, further contributing to the backwater effect. A portion of the willows (along approximately 1,070 linear feet) that are identified as obstructing flow would be removed (Figure 2). The willows will be primarily removed by hand , but some small , hand-held, mechanized machinery may also be used . The reed canarygrass that is growing in the channel will be removed with machinery, most likely a trackhoe, operated from the stream bank. During removal of the reed canarygrass, the stream would be diverted around the construction site and erosion/sediment control best management practices will be implemented to minimize temporary downstream water quality impacts. 3 Figure 2. Willow Pruning Exhibit 1.2.1.2 Sediment Removal The selective p1 w1lng of the exhtJng willows would be done as shown ln the ntrnched picture The objective or the prnnlng would be to reduce tl1e b1 nnches thnt cross the strerun nod catch ieed canary guss mots that biel\lc loose upstrtrun 1. The willow b1 ru1cbes (1 ed nrrow) t11nt are below the wntei would be prwied bn c k to the mnln ti wlk or the willow 2 . The willow b1 rui ches (blue nrrow) would be pnmed so thnt tbey would not block flows that ftl'e coutnlned within the sh earn banks. 3 The wUlow b1 anc hes (ye llow 1 1 rows) thnt p1 ovtde the shade cnnopy ror the strerun would not be tou ched . ~ The root system of the wlllow thnt is p1 oviding bank stability mad strenm complexity wou ld not be touc bed. The second component of the project includes the removal of accumulated sediment from the stream channel. Sediment would be removed using machinery, most likely a trackhoe, operated from the stream bank. As with the vegetation removal process described in section 1.2.1. l ., the stream would be diverted around the construction s ite and erosion/sediment control best management practices will be implemented to minimize temporary downstream water quality impacts. Construction techniques, such as utilizing existing access roads or using non-permanent steel plates (or equivalent) where additional access is needed, would be used to minimize temporary impacts to adjacent wetlands. Approximately 4,050 cubic yards of material will be removed from the stream channel. Sediment removed from the stream will be temporarily stockpiled in designated soil drying areas {Appendix B, Sheet 2 and 3) immediately after removal from the stream. Once the soil is dry, it will be hauled offsite and disposed of at an approved locati on. 1.2.1.3 Channel Modification May Creek's channel will be modified by the dredging activity, as well as by in-stream mitigation activities. The dredging activities will result in a uniform channel elevation at 308 feet {NA VD 88) with varying channel cross sections {Appendix B, Sheet 4). This channel modification will occur in May Creek from approximately river mile {RM) 4.3 to RM 4.9. The dredging construction techniques were described above. 4 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I • I 1.2.1.4 Conservation Measures The mitigation was designed to provide compensation for removal of existing in-stream vegetation (i.e., reed canarygrass and willows) and sediment by enhancing the existing riverine wetland and riparian buffer, as well as restoring instream habitat function at the confluence of Long Marsh Creek and May Creek. King County has developed multiple basin reports and action plans for the May Creek subarea over the years and the proposed mitigation incorporates the results of these studies. The mitigation goal for this project is to increase project longevity and to achieve no overall net loss in habitat functions in the May Creek subbasin. In most of the project area the regulatory stream buffer is contained within the delineated wetland boundary, which means that stream buffer enhancement could also be considered wetland enhancement. Compensatory mitigation objectives include: Wetland Habitat: Enhance about 2.24 acres (this includes 2.0 acres of riparian habitat described below) of riverine wetland adjacent to May Creek downstream of 148th Avenue SE by suppressing invasive vegetation and replanting native wetland vegetation. About 0.24 acre of this enhancement will be in the form of off-channel alcoves along May Creek with emergent wetland vegetation, woody debris, snags, and gravels. This mitigation will enhance fish and wildlife habitat by increasing habitat complexity. Riparian Habitat: Enhance about 2.0 acres (included in the 2.24 acre of wetland habitat) of riverine wetland/May Creek buffer by suppressing invasive species and planting a 15- feet wide buffer of native vegetation along both banks of May Creek from 148th Avenue SE upstream to the end of the project limits (about 2,500 linear feet on each stream bank). This buffer is intended to shade out future reed canarygrass and to compensate for the cover that would be lost by removing flow obstructing willows and reed canarygrass. The native riparian vegetation would be planted in areas where, under existing conditions, virtually no native vegetated buffer exists. Fencing will also be installed around the planting areas to minimize livestock access to the stream. In-stream habitat and function: In-stream mitigation activities will occur in two locations. In the first location, 0.24 acre of off-channel alcoves (these are the same alcoves described above under Wetland Habitat) will be excavated along May Creek west of 148th Avenue SE. The existing banks will be replaced with a terrace (wide bench) and gradual slopes. Sixteen (16) pieces of large woody debris (LWD) will be placed and native vegetation will be planted in the alcoves (Appendix B, Sheet 2) and streambed gravels will be placed along the first 15 feet adjacent to May Creek. Jute matting will be placed in the alcoves beyond 15 feet to minimize erosion, and the alcoves will be densely planted with emergent and scrub-shrub wetland plants. During a flood, water will inundate the terrace and interact with the woody debris and vegetation. This will increase the amount of available in-stream habitat and will decrease flow velocities, thus improving the quality of off-channel overwintering habitat. Sediment deposition will occur outside of the main channel in the alcoves. The woody debris and vegetation will trap and hold sediment and then allow a more gradual pulsing of sediment back into the channel over time . 5 The second location will restore in-stream fish habitat complexity and alluvial fan functions at the confluence of Long Marsh Creek and May Creek. The project will enhance approximately 300 feet of the lowest reach of Long Marsh Creek by creating meanders, adding habitat features, and planting native vegetation. These enhancements will improve the sediment trapping capabilities of the Creek to reduce transport of sediment to May Creek. The enhancement also includes creation of an approximately 100 foot long side channel parallel to May Creek that will join with Long Marsh Creek prior to discharging to May Creek. (Appendix B) This mitigation will improve winter rearing habitat for salmonid and other fish species in areas adjacent to the mainstem of May Creek. The mitigation will increase biological functions for riparian species within May Creek through introduction of woody debris; woody debris will also provide substrate for invertebrates, hiding habitat for juvenile fish, perching habitat for riparian birds, and desirable niches for river otters, other mammals, and crustaceans. The proposed mitigation is also designed to enhance refuge and rearing habitat through the establishment of habitat features along May Creek. Such enhancements would make these habitat features available to salmonids and other wildlife species at a wider range of May Creek flow rates. In addition, willows and other native shrubs will be planted along streambanks and confluence margins to increase cover of overhanging branches above the waterways. Lastly, the removal of reed canarygrass and root system from the floodplain will create additional area for sediment deposition, thereby allowing some decrease in the volume of fine sediment moving downstream. 1.2.2 Project Sequencing and Timeline Project construction is expected to take three to four weeks to complete, with plantings occurring in the spring. The timeline detailed in table 2 assumes the in-water work window issued by WDFW to be August 1-31, which is typical for tributaries to Lake Washington. 6 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Table 2. Construction Sequencing and Timeline Date I-Aug 4-Aug 4-Aug 5-Aug 5-Aug 6-Aug 7-Aug 14-Aug 26-Aug 30-Aug I-Sep 17-0ct I-Apr Activit Locate and Mark Utilities Install Temporary Erosion and Sediment Control (TESC) Measures Install Temporary Construction Access Ramps and Entrance Pads Install Staging Areas Fish Removal Install Stream Bypass (in-water) Selective Removal of Vegetation Sediment and Reed Canary Grass Removal (In Channel) Construct Mitigation Area (grading and LWD) Remove Temporary Stream Bypass (in-water) Remove Temporary Access Ramps and Pads Remove TESC Best Management Practices (BMPs) Install Plantings 1.3 Impact Avoidance and Minimization Measures The following project elements will be implemented in order to minimize project impacts on listed species. Site and Equipment Preparation: o The contractor will install temporary high-visibility fencing and silt fencing to demarcate clearing limits and protect sensitive areas according to the approved TESC plan. No work, including the placement or stockpiling of fill materials or excavated materials, will be performed in any sensitive area. When it is no longer needed or at the engineer's direction, the contractor will completely remove and properly dispose of temporary high-visibility fencing and silt fencing. o A TESC plan and a Spill Prevention, Control, and Countermeasures (SPCC) plan will be developed and implemented by WLRD for this project and will be used at all times. As construction progresses, erosion-control measures will be re-located or newly installed if necessary so that as site conditions change erosion and sediment-control measures are always functioning in accordance with local and state erosion and sediment-control standards. Construction Equipment: o Refueling operations will be conducted at a minimum distance of 100 feet from an open water body, or ditch, and an SPCC plan will be prepared by the contractor and approved by WLRD prior to the initiation of construction to ensure that all pollutants and products are controlled and contained. Additionally, drip pans will be fitted with absorbent pads and placed under all equipment being fueled. 7 • All vehicles operated within 100 feet of the creek will be inspected daily for fluid leaks before leaving the vehicle staging area. Any leaks detected will be repaired before the vehicle resumes operation. When not in use, vehicles will be stored in the vehicle staging areas. • Construction equipment will use existing farm access roads, whenever possible to cross wetlands. • Construction equipment will not enter any water body without authorization from WDFW, as appropriate. Equipment will be operated as far from the water's edge as possible. Debris. Erosion, and Disturbed Areas: • The contractor will install temporary high-visibility fencing and silt fencing to demarcate clearing limits and protect sensitive areas according to the approved TESC plan. No work, including the placement or stockpiling of fill materials or excavated materials, will be performed in any sensitive area. When it is no longer needed or at the project manager's direction, the contractor will completely remove and properly dispose of temporary high-visibility fencing and silt fencing. • All debris from construction and removal activities will be contained and disposed of in accordance with federal, state, and local laws. • Erosion of disturbed areas will be controlled using silt fence staked and keyed-in ( depth of five inches); use of mulching or hydroseeding, planting disturbed areas to establish cover vegetation, or other similar approved methods to contain erosion. • All exposed areas that will be unworked for more than seven days during the dry season (May I to September 30) and two days during the wet season (October I to April 30) will be covered in accordance with the project's TESC plan. • Disturbed areas will be restored to pre-project conditions or better, using site- appropriate native plant species. Stream Work: • In-water work will be conducted during the in-water work window listed in the hydraulic project approval issued by WDFW. Typical windows for tributaries to Lake Washington allow an in-water work window of August I to August 31, though final approval from WDFW has not been issued. o In-water work will be limited to activities required to bypass the creek, including fish exclusion and installation of cofferdams. The remainder of project activities will occur once the stream has been bypassed. • Work will not inhibit passage of any adult or juvenile salmonid species after project completion. • Sediment-laden water generated during construction will be pumped to an infiltration or filtration site, or to a settling area, where it is subsequently treated and sediments are consolidated prior to returning water to streams. Discharge of water back to streams will occur in such a manner as not to cause erosion. o Machinery access along the stream, in areas where there is a willow canopy, will only be allowed approximately every 50 feet to minimize disturbance to native vegetation. 8 fl I I 0 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I • In-stream willow removal will be limited to the minimum amount required to restore flow conditions. Branches that are crossing the stream and obstructing flow will be removed by pruning the branches back to the trunk. Willows that are providing canopy cover for the stream without obstructing flow will not be removed , and similarly, the willow roots that are providing bank stability will not be removed. 1.4 Action Area The action area includes all areas that could potentially be affected directly and indirectly by the federa l action, and not merely the immediate area involved in the action (50 CFR 17 .11 ). This area is the geographic extent of the physical, chemica l, and biological effects resulting from the Project, including direct and indirect effects, and effects of interrelated and interdependent activities. Effects from the project are not expected beyond the action area (Figure 3). Terrestrial : The terrestrial portion of the action area is delineated by the point at which project related noise generated by co n struction equipment attenuates to background noise levels. Construction noise levels where estimated assuming use of dump trucks and trackhoe/excavator and the distance at which noise levels attenuate to background is 1,200 feet. Aquatic : In the aquatic portion of the action area, the effects from project activities would occur through water-quali ty impacts . Direct effects from turbidity and siltation resulting from construction activities will be minimized through the implementation of BMPs and impacts are not expected to extend beyond l 00 feet downstream as required under Washington Administrative Code I 73-201A-200. This limit was established based upon the type of construction activities that are to occur, the location of those activities in relationship to the creek, timing of construction, and the implementation of BMPs through the TESC plan . Indirect effects resu lting from reductions in sediment transport may extend 3 .2 miles downstream of the project, near the confluence with Lake Washington. Sediment potentially transported this distance is assumed to deposit in the lower 2,000 feet of May Creek, where the gradient becomes less than one percent. 9 ..... 0 -------------- May Creek Channel Restoration Project Action Area Legend c:JAdlonArea -Streams and Rivers * ProJect Loca1lon King County Overview :-,; ~?- 0.2 0.1 0 0.2 0.4 0.6 Miles ~ U1 King County nt 11) .... lldKldOl •tmp lablttcmaplkl"1' :a,~~~.awa•"•ao1a,aaa,.,.cst, U9C0.1\'U;t1 IO•JIHHlaiUOfWiilllMWK.t~pwu. otlllp•<La blt~U~j'.OCllpHl'"', .... t:U ,ot *Ji' 1>9'1! IU Oflld tt>IUW>t. in cmo•un .at111• MIHf or eu a a U 1tfVPl)-.t Jl')c»t •t,&liltotl» ....... ,,, .... ~ ldllfCllc:Utt'QI.OlcotUqMl'lilldaqt: ltcldtg.bst IOl~ ltdb. bltfflU Kot bdpa"& •u•g-•t ~::::s'!: ~-=--=--~:,•:.:.Ti.cl ~wt-•pt•UDtOfUgO>et1f. --- ~ (IQ. = "'I ~ ~ "'Cl "'I Q ...... ~ -> t') Q; Q = > .., ~ = -11111 I I I I I I I I I I I I I I I I I I I 2 lFEDERAlLlLY LISTED FISH AND WIJLDJLIFE SPECIES TN THE ACTION AREA Based on a review ofan endangered species listing provided by the WDNR (dated November 5, 2010) and NMFS (accessed January 24, 2011; revised July I, 2009) the following species have been evaluated as part of this biological evaluation: Chinook salmon and steelhead trout (Table I). 2.1 Chinook Salmon In 1998, NMFS conducted an ESA status review of Chinook salmon populations from Washington, Idaho, Oregon, and California and determined that Chinook salmon in the Puget Sound region constituted an evolutionary significant unit (ESU) and that the Puget Sound ESU is at risk of becoming endangered in the foreseeable future (Meyers et al., 1998). Following this status review, the Puget Sound ESU was federally listed as threatened in 1999 (Federal Register 1999). Primary factors attributed to population declines include habitat blockages, hatchery introgression, urbanization, logging, hydropower development, harvests, and flood control and flood effects (NMFS 1998). Chinook salmon are not present at the project location, but have been documented approximately one mile downstream, within the project action area; lifestages present include adult spawners and rearing juveniles. Adult Chinook typically arrive on the spawning grounds in May Creek in October and finish spawning in November. Fry begin emerging in January and continue through early-to mid-March. Juveniles typically rear in fresh water for a few months before migrating downstream in the spring. Chinook in May Creek likely represent fish straying from the Cedar River and Issaquah Creek and do not represent a reproducing population. Nearly all spawning occurs in the lower two miles of May Creek, though spawning has been observed up to RM 3.0. The number of Chinook observed in May Creek varies between zero and 12 fish annually (pers. comm. Aaron Bosworth, WDFW, November 15, 2010). Preliminary results of WDFW spawner surveys conducted in 2010 in May Creek observed three live Chinook and one redd. Surveys were conducted weekly from September 22 to November 10 and the Chinook were observed on a single survey within the middle reach (RM 0.4 to 1.8). 2.1.1 Critical Habitat No critical habitat is designated in May Creek; the nearest critical habitat for Chinook salmon occurs in Lake Washington approximately 4.3 miles downstream of the project location, below the downstream extent of the action area. 2.2 Steelhead Trout Puget Sound steelhead were listed as a threatened species on June 11, 2007 (FR Vol 72, No 91 p 26722). The DPS includes all naturally spawned anadromous winter-run and summer-run steelhead populations, in streams in the river basins of the Strait of Juan de Fuca, Puget Sound, and Hood Canal, Washington, bounded to the west by the Elwha River (inclusive) and to the north by the Nooksack River and Dakota Creek (inclusive), II as well as the Green River natural and Hamma Hamma winter-run steelhead hatchery stocks. 0. mykiss can be anadromous or freshwater resident (and under some circumstances, apparently yield offspring of the opposite form). Anadromous 0. mykiss are called steelhead and non-anadromous (freshwater resident) forms of the species are usually called rainbow trout. Those that are anadromous spend one to four years in fresh water prior to smoltification, although most within the Puget Sound ESU smolt after two years in fresh water. Steelhead then spend one to four years at sea before returning to their natal streams to spawn. The steelhead run in the Lake Washington basin is characterized as "depressed" (WDFW, 1992). Past hatchery practices by WDFW included planting of steelhead fry throughout tributaries in the Lake Washington/Lake Sammamish Basin and were unsuccessful in producing return adult spawners. The Cedar River has a naturally spawning population of steelhead and weekly surveys are conducted annually to assess abundance. Redd counts have been steadily declining and 20 lO surveys observed only one redd (pers. comm. Hans Berge, King County, November 22, 2010). Steelhead occurring in the project action area are part of the Lake Washington winter-run population. They typically enter fresh water between November and April and spawn from late-March through early June. Survey data from 1984 though 1987 observed steelhead in the lower reaches of May Creek (Newcastle 2002). Data from the WDFW Salmon Scape website (accessed November 22, 20 I 0) report that steelhead have been observed in the lower three miles of May Creek, with the nearest observation 0. 75 mile downstream of the proposed project. 2.2.1 Critical Habitat Critical habitat has not been designated for the Puget Sound steelhead DPS. 3 ENVIRONMIENl'AL §JETTING 3.1 May Creek Basin Overview The mouth of May Creek is located on Lake Washington approximately two miles north of the Cedar River in Renton, Washington. The May Creek Basin drains an area approximately 14 square miles west of the Cascade Foothills between Issaquah Creek, Coal Creek, and the Cedar River. The headwaters of the basin include Cougar Mountain, Squak Mountain, and the East Renton Plateau. The main stem of May Creek contains approximately seven river-miles of habitat and is fed by 13 primary tributaries. There are two lakes in the drainage, Lake Kathleen and Lake Boren that form the headwaters of the South Fork May Creek and Boren Creek, respectively. The northern portion of the basin includes Cougar Mountain Regional Wildland Park and some low-density residential development (City of Newcastle 2002). In the flat floodplain and wetlands of May Valley, the creek broadens and slowly flows through rural pastures, small commercial areas, and suburban development (King County 200 I). Land use in the southern May Creek basin includes low and high-density single-family development, commercial development, forest lands, and meadows. 12 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I May Valley is largely composed of a natural floodplain that periodically filled with floodwaters even before this region was settled. May Valley was cleared and drain ed around the beginning of the last century, and has supported agricultural and residential u ses ever since. Sediment eroded from streams in the Highlands and East Renton Plateau is gradually reducing the capacity of the May Creek channel in May Valley and until the 1990s, portions of the channel were maintained by landowners who removed sediment deposits and stands of choking vegetation (King County 2001 ). Analysis of past, existing, and forecast storm runoff and flooding conditions of the May Creek Basin indicate that flooding has increased significantly and will probably continue to increase as the basin is developed (KCSWM, 1995). As more development occurs throughout the basin, many of these problems are anticipated to worsen unless steps are taken to address these issues (King County 2001 ). 3.2 Habitat Conditions at the Project Location 3.2.1 Aquatic Resources Aquatic resources directly impacted by the proposed project include May Creek and Long Marsh Creek. Stream surveys were conducted and the results are summarized below, additional detailed information can be found in the King County Baseline Stream Conditions Report (2010). May Creek May Creek at the project location is dominated by slow water glides. The creek has two primary channel forms , which are influenced by the riparian plant community. In areas where willows are present and in contact with stream flow , the channel form appears to be mostly forced pool riffle, with pools being forced by scour against channel-spanning willow branches or willow stems within the active channel. In areas where riparian vegetation consists of reed canarygrass or trees high on the banks, the channel form appears to be plane-bed. Both channel forms derive from past excavations and ditching for agriculture and sediment deposition. The channel gradient is flat throughout. Aquatic habitat is more complex in places where the riparian corridor has woody plants, such as willows, engaged with the stream channel and connected floodplain. Overhanging or rooted willow branches or sterns provide cover and hard points necessary for bedform complexity, producing both turbulent and non -turbulent flow areas (King County 20 I 0). Areas with no woody riparian plants are much more uniform and tend to have accumulations of fine sediments in the channel (Photos 1-5). Long Marsh Creek Long Marsh Creek is a tributary of May Creek that drains portions of the south side of Cougar Mountain. In-stream habitat below SE May Valley Road is somewhat shallow low-gradient riffle with little to no pools. The stream is maintained in a relatively straight alignment by property owners to the streams confluence with May Creek (Photo 6). 13 Photo 1. Looking upstream toward Red Barn August 2010 Photo 3. May Creek looking downstream August 2010 Photo 5 . May Creek channel 14 Photo 2. Looking upstream toward Red Barn February 2010 Photo 4. May Creek look ing downstream February 2010 Photo 6. Long Marsh Creek, looking upstream from May Creek I I I I I ' I I I I I I I I I I I I I I I I I I I I I I I IJ I Ii I • I I I I I 3.2.2 Wetlands One large riverine wetland, referred to as May Creek #5 in the King County Wetland Inventory ( 1990), is located at the project location. This wetland is approximately 140 acres in total size, and approximately 25 acres of it is contained in the project study area that was delineated for this project (King County, 2010). The results of the delineation report are summarized below. May Creek #5 is a Category 11 riverine wetland with a 110 foot buffer, located in the natural l 00-year floodplain of May Creek. The wetland has been degraded over the years by adjacent farming and agricultural uses. Many areas of the wetland are actively mowed and used for grazing horses and other livestock. On the north side of the wetland, the wetland boundary closely follows a line of fill that appears to have been placed in wetland areas over the years to facilitate farm use. On the south side of the wetland, the wetland boundary more closely follows the natural valley topography. While fairly degraded due to adjacent land use practices, it received a Category 11 rating due to its high potential and opportunity to provide flood storage and improve water quality along with its moderate potential to provide habitat to a variety of species. The hydrology source to the wetland is a combination of overbank flooding from May Creek and a high groundwater table. Numerous groundwater seeps were identified on the valley walls. The wetland is primarily palustrine emergent with some scrub- shrub/forested components that are concentrated near May Creek. The vegetation in this wetland has been degraded by the adjacent fanning and agricultural uses. Many areas of the wetland are actively mowed and used for grazing, and therefore contain pasture grasses that could not be accurately identified given the season (late January) and regular mowing. In a majority of the wetland areas not regularly mowed, the dominant vegetation was reed canarygrass (Phalaris arundinacea), which grows in thick blankets with almost 100 percent coverage. The only unmowed areas without reed canarygrass were in the scrub-shrub/forested components of the wetland where the reed canarygrass was shaded out. 3.2.3 Geology The wide and relatively flat May Valley (RM 3.9 to RM 7.0) was created by glacial ice melt runoff and is part of the "Kennydale Channel". The valley is underlain by recent alluvium over recessional outwash deposits and compacted glacial till. These deposits overlie Eocene Tukwila Formation. The formation is composed of volcanic tuff, fine- grained volcanic sandstone and volcanic tuff-breccia. The formation is reported to outcrop west of 146 1h and forms a physical boundary between the downstream ravine and May Valley upstream. The creek gradient within May Valley is 0.2 percent and the valley is predominately a depositional environment. Aerial photography and Lidar image of the valley show evidence of pre-dredging channel meanders. Historic survey mapping from 1872 show May Creek as a meandering stream and Tributary 0291 a extending north to join May Creek just south of Indian Meadows rather than the current confluence approximately 1440 feet west of 1641h Ave SE. The alluvial fans from Indian Meadows and Long Marsh Creeks appear on the 1872 map and the mapped location of May Creek 15 is routed to the southwest around the higher elevations of the Long Marsh/Indian Meadows alluvial fans. The historic channel map for 0291a is consistent with Lidar images showing meander scars in the valley. 4 ElFlFEC1'S OlF ACl'lfON 4.1 Direct Effects No direct effect on listed species will occur because these species are not present at the project location. Direct effects are analyzed below in Section 6 for the essential fish habitat consultation. 4.2 Indirect Effects Indirect effects arc those impacts that are caused by the action and occur later in time (after the action is completed) but arc still reasonably certain to occur. Indirect effects from modification of May Creek and Long Marsh Creek will result in long-term habitat alterations. These effects include temporary increases is stream temperature from riparian clearing and modification to sediment transport. A technical memo prepared by King County to assess sediment conditions in May Creek is provided in Appendix Band summarized below. The project proposes a number of features to reduce sedimentation to May Creek and channel filling. These include native plant buffers along the banks, removal and control of reed canarygrass, reduced overbank flooding, selected removal of vegetation from the channel downstream of 148'h Ave SE, and a sediment management design for Long Marsh Creek. These features are expected to produce the following effects: • Adding plant buffers on either side of May Creek will locally reduce the amount of sediment reaching May Creek from rainfall runoff. Where reed canarygrass is present above the channel slopes, the grass is effective at catching and trapping sediment. • Removal and control of reed canarygrass will slow channel narrowing and infilling due to growth during spring and summer during low flows. • Reducing over bank flooding of pastures will reduce the amount of sediment and organic material being carried to the creek by an estimated 0.21 to 0.84 metric tons per year. • Improved channel hydraulic efficiency will improve and move fine sediment and organic material that reaches the creek downstream, reducing the amount of sediment trapped in reed canary grass above 148th Ave SE. • The proposed alcove excavation and planting areas west of 148 1h Ave will allow the creek to overflow into the alcoves during higher flows, this will slow the current velocities allowing sediment to drop out of suspension, but the actual amount of deposition is unknown. • The May Creek channel is likely to be both a depositional area and a source of suspended sediment during higher flows. Soft muck in the stream bottom above the confluence with Long Marsh Creek is a combination of organic material from pasture runoff with mineral sediment. The muck builds up in the channel after rain storms 16 I I I I ' I I I I ti I I I I I I I I I II I I I I I I I I I I I I I I I I I I I • A mitigation project in Long Marsh Creek will intercept gravel and large sand size sediment before it reaches May Creek. • Following bank stabilization with jute netting and seeding will reduce erosion and sediment input to May Creek. The May Creek Current and Future Conditions report (King County, 1995) identified the major sources of sediment to May Creek as coming from the ravine and tributaries below May Valley. The hydraulic analysis (King County, 2010a) shows that changes in flow velocity below 143rd Ave SE will be negligible. Sediment movement is controlled by flow. Therefore, the same size sediments would be moved within the May Creek system. We estimate the project related reductions in sediment delivered to the creek primarily from reduced overbank flooding, will reduce the total fine sediment and organic muck in the stream. In general, fine sediment that does enter the creek as bedload or suspended sediment will move downstream due to improved channel efficiency rather than being stored in the creek channel above 148th, incorporated into the banks or moving though during large flow events. Some fine sediment or muck entering the creek will continue to be stored behind topographic highs and lows in the channel above and below 148 1h Ave. At issue are the potential indirect effects of exposing adult, juvenile, and embryonic Chinook salmon to degraded water quality associated with sedimentation. Project activities will result in the removal of channel sediment and existing vegetation. Temporary impacts include sedimentation, loss of shade, and loss of organic detritus recruitment. Permanent beneficial effects include a net reduction in sedimentation and establishment of a riparian buffer planted with woody vegetation. Sedimentation and turbidity from land use activities can degrade salmonid habitat (Bash et al., 2001 ). Other impacts associated with elevated turbidity levels include behavioral modification, gill trauma, increased stress, reduced osmoregulation, modification of blood chemistry, reduced growth, reduced forage success, higher predation, redd damage, and lower reproduction. High levels of suspended solids may be fatal to salmonids, while lower levels may cause chronic sub-lethal effects (Lloyd et al., 1987). Juveniles and eggs appear to be more sensitive to sedimentation and turbidity than do adults (Lloyd et al., 1987). Sedimentation and turbidity are normal occurrences in natural streams and can periodically reach relatively high levels. Depending on the time of year and location of the sediment discharge, increased turbidity could negatively affect an individual's ability to forage, seek shelter, and access cold-water refuge. The size of the sediment particles and flow velocities can affect the duration of sediment suspension in the water column. Larger particles (> 2mm), such as sand and gravel, typically settle rapidly, but silt and very fine sediment may be suspended for several hours. Suspended solids can potentially reduce light transmission and, if chronic, may suppress primary production negatively affecting the feeding success of juvenile Chinook. Sediment and turbidity also have the potential to modify adult migration and spawning. Limiting the in-water work to approved construction windows when few, if any, Chinook are present and the implementation, maintenance and monitoring of appropriate BMPs to reduce the risk of discharges of fine sediments will limit any potential impacts to Chinook. 17 Physical removal of muck (fine sediment) within the channel, maintaining topographic controls (i.e. bridge at l 48t1'), creating off-channel alcoves for deposition, and establishing riparian buffer with woody vegetation will reduce or eliminate the potential to introduce fine sediment into water containing listed species. By taking these protective measures it is unlikely that any life stage of Chinook will be negatively impacted by sediment discharges from this project. Additionally, effects on steelhead are expected to be similar to those described above for Chinook. 4.3 Effects from Interrelated and Interdependent Actions An interdependent activity is an activity that has no independent utility apart from the proposed action. An interrelated activity is an action that is part of a larger action and depends on the larger action for its justification. No interrelated or interdependent actions will occur as a result of the proposed project action for Chinook, steelhead, or bull trout. 18 fl I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 5 CONCLUSIONS The determination of effects for protected fish species is contingent upon implementation of the previously identified impact minimization measures and mitigation. The proposed action may have the following impacts on Chinook and steelhead trout (Table 3): I) Modifications in sediment transport described in chapter 4.2 have the potential to indirectly impact fish within the project action area. 0 0 Preliminary assessments of sediment loading (Appendix B) indicate a net reduction in sediment loading resulting from the project While some topographic controls will remain in place, removal of channel obstructions will allow sediment to pulse through during smaller flow events. 2) Temporary removal of riparian vegetation has the potential to indirectly disturb or harm fish within the project action area. o Temporary clearing of riparian vegetation will result in elevated summer stream temperatures. Based on post construction monitoring of similar activities, we anticipate elevated stream temperatures for approximately five years. Considering the information referenced in this report and project information provided in the construction plans, an effect determination of may affect is appropriate for Chinook and steelhead trout because: o Chinook presence has recently been documented downstream of the project within the action area. o Steelhead presence has historically been documented downstream of the project within the action area The project is not likely to adversely affect these species because: o The project is proposed to occur during the designated in-water work window (Augustl-31) when species, primarily Chinook, are least likely to be present. o These species are not present at the project location where direct impacts would occur. o Short-term water quality effects to listed species resulting from rewatering of the newly excavated channel will be discountable or insignificant. o Long-term water quality effects to listed species resulting from net reductions in sediment loading will be insignificant. o Short-term effects to species from elevated stream temperatures resulting from riparian clearing will be discountable and/or insignificant. 19 o Permanent beneficial effects from mitigation elements will result in riparian, in- stream, and wetland improvements. o Potential impacts described above will be reduced through impact avoidance and minimization measures. Table 3: Summary of Project Effects on Species Protected Under the ESA Species Federal Status Life Stages Effect Determinations Considered Chinook Salmon (Oncorhynchus Threatened All freshwater May affect, not likely to adversely tshawvtscha\ phases affect Steelhead Trout (0. mykiss) Threatened All freshwater May affect, not likely to adversely phases affect Essential Fish Habitat Mav Creek Will adverselv effect 20 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 6 MAGNUSON STEVENS FISHERY CONSERVATION AND MANAGEMENT ACT Action Agency: King County Department of Natural Resources and Parks Project Name: May Creek Drainage Improvement Project (9Al205) 6.1 Essential Fish Habitat Background The Magnuson-Stevens Fishery Conservation and Management Act, as amended by the Sustainable Fisheries Act of 1996 (Public Law 104-267), requires federal agencies to consult with NOAA Fisheries on activities that may adversely affect essential fish habitat (EFH). The objective of this EFH assessment is to determine whether or not the proposed action(s) "may adversely affect" designated EFH for relevant commercially, federally- managed fisheries species within the proposed action area. It also describes conservation measures proposed to avoid, minimize, or otherwise offset potential adverse effects to designated EFH resulting from the proposed action. Pacific Coast Salmon NMFS has designated EFH for Pacific Coast salmon, including Chinook, coho and pink salmon, in Amendment 14 to the Pacific Coast Salmon Plan (NMFS 2000a). Within the action area, May Creek and Long Marsh Creek contain EFH for species present ( Chinook and coho salmon). The Pacific salmon fishery EFH includes all those streams, lakes, ponds, wetlands, and other water bodies currently or historically accessible to salmon in Washington, Oregon, Idaho, and California, except above the impassable barriers identified by the PFMC (1999). Construction projects can significantly alter land surface, soil, vegetation, and hydrology, and can adversely impact salmon EFH through habitat loss or modification. Among numerous types of non-fishing activities that may affect EFH, should BMPs fail, those applicable to the action area are those that will: o Alter sediment delivery to, and quantity in, streams and estuaries; o Alter water flow, quantity, timing, or temperature; o Alter the amount or types of nutrients or prey. o Discharge pollutants, nutrients, or contaminants. 6.2 Description of the Proposed Action The proposed action, environmental baseline, and action area are described in Chapter 1.2, Description of Proposed Project Action; Chapter 1.4, Action Area; and Chapter 3, Environmental Setting of this BE. The action area includes Chinook and coho rearing and spawning habitat. Proposed project actions include: o Clearing, grubbing, grading, and dredging; o Work area isolation via stream bypass; o Habitat enhancement and creation, and site restoration; o Landscaping and planting. 21 6.3 Adverse Effects Essential Fish Habitat for Salmonids The determination of the effects of the proposed project on EFH is based on Section 305(b)(2) of the Magnuson-Stevens Act. Under this act, federal agencies are required to consult with NMFS regarding any of their actions or proposed actions authorized, funded, or undertaken that may "adversely affect" EFH. "Adverse effect" means any impact which reduces the quality and/or quantity ofEFH. This can include direct (e.g., contamination, physical disruption), indirect ( e.g., loss of prey, reduction in species' fecundity), site-specific, and habitat-wide impacts, including individual, cumulative, or synergistic consequences of actions. Project effects to ESA listed species are described in Section 4 and will also apply to coho in May Creek. In addition to those indirect effects, coho are present at the project location and will be directly impacted by the project action. Adverse effects from dredging of 2,000 linear feet of channel will result from an alteration in availability and quality of migration/rearing habitat for coho salmon in May Creek. Strict adherence to BMPs (see Section 1.3) will minimize impacts to water quality in May Creek during project construction and proposed mitigation is designed to offset the operational impacts. Overall, there will be direct (coho) and indirect ( coho and Chinook) effects upon Pacific Coast salmon EFH during project construction, but the proposed conservation measures and project BMPs will limit the scope and scale of the impacts, and no large-scale deleterious effects are expected to occur. 6.4 Essential Fish _Habitat Conservation Measures Conservation measures will be implemented to minimize the potential adverse effects on designated EFH are described in Chapter 1.3 6.5 Conclusions Based on the EFH requirements of Pacific Coast salmon species, BMPs, and conservation measures proposed as part of the project, the determination is that the project will adversely affect EFH for coho salmon. 22 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 7 REFERENCES Bash, J.C. Berman, and S. Bolton. 2001. Effects of turbidity and suspended solids on salmonids. Center for Streamside Studies, University of Washington. Berge, Hans. Senior Fish Biologist, King County Water and Land Resources Division. 201 South Jackson Street, Seattle, Washington. Personal Communication on November 22, 20 I 0. Bosworth, Aaron. Anadromous Fish Biologist, Washington Department of Fish and Wildlife. 16018 Mill Creek Boulevard, Mill Creek, Washington. Phone Conversation on November 15, 20 I 0. City ofNewcastle. 2002. City ofNewcastle 2001 Stream Inventory. Prepared by Adolfson Associates Inc. for City of Newcastle, January 2002. Newcastle, Washington Federal Register, Vol. 72, No. 91 Friday, May 11, 2007. Final rnle. Endangered and Threatened Species: Final Listing Determination for Puget Sound Steelhead. Federal Register, Vol. 64, No. 147 Monday, August 2, 1999. Final rule. Endangered and Threatened Wildlife and Plants; Listing of Nine Evolutionarily Significant Units of Chinook Salmon, Chum Salmon, Sockeye Salmon, and Steelhead. King County. 1995. May Creek Current and Future Conditions Report. Prepared by Foster Wheeler for King County Department of Natural Resources and Parks. Prepared for Stormwater Services Section, Capital Services Unit. King County and City of Renton. 200 I. Final Adopted May Creek Basin Action Plan. King County Surface Water Management Division and Renton Department of Public Works, April 2001. Seattle,Washington. King County. 2010. Baseline Stream Conditions May Creek Drainage Improvement Report. King County Water and Land Resources Division, March 2010. Seattle, WA King County. 2010a. DRAFT Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project. Prepared by Jeff Burkey, King County Department of Natural Resources and Parks. Prepared for Storrnwater Services Section, Capital Services Unit. King County. 2010b. May Creek Channel Restoration Project, Wetland Delineation Report. King County Water and Land Resources Division, March 2010. Seattle, WA Lloyd, D.S., J.P. Koenings, J.D. LaPerriere. 1987. Effects of turbidity in freshwaters of Alaska. North American Journal of Fisheries Management. 7: 18-33. 23 NMFS (National Marine Fisheries Service). 1999. Essential fish habitat consultation guidance. Office of Habitat Conservation. NMFS (National Marine Fisheries Service). 2000a. Appendix A: Description and identification of essential fish habitat, adverse impacts, and recommended conservation measures for salmon. Amendment 14 to the Pacific Coast Salmon Plan. Pacific Fishery Management Council (January 1999). Available from the PSMFC Web site: http://www.pcouncil.org/ NMFS (National Marine Fisheries Service). 2000b. Magnuson-Stevens Fishery Conservation and Management Act and essential fish habitat. Available from NMFS Northwest Region Habitat Conservation Division Web site: http://www.nwr.noaa.gov/habcon/habweb/msa.htm. PFMC (Pacific Fishery Management Council). 1999. Appendix A: Description and identification of essential fish habitat, adverse impacts, and recommended conservation measures for salmon. In: Amendment 14 to the Pacific Coast Salmon Plan. Available from PFMC Web site: http://www.pcouncil.org/ WDFW and Western Washington Treaty Indian Tribes. 1994. 1992 Washington State Salmon and Steelhead Stock Inventory (SASS[) Appendix One: North Puget Sound Volume. WDFW. 1998. l 998 Washington Salmonid Stock Inventory Bull Trout and Dolly Varden Appendix. WDFW, 2010. Salmonscape Interactive mapper -Salmon presence. Available at: http://wdfw.wa.gov/mapping/salmonscape/. Accessed on November 22, 2010. 24 I I I I I I I I I I I I I I I I I I I Endangered Species Act Status of West Coast Salmon & Steelbead (l 'pd11ud Ju(r J, 1009} Currem Sprrlr1;1 E11da11gered ESA I./Stl11g Actlo11s Species Acl Under Rn•iew Lisi/no Slallli 1 Snakc Rfrc1 '"'11'!'!.J.i~".~ -Sockey,: Salm.on ' Ozcm: Lal:c (011rorl1.t·nrhiu llf'l"hi) 3 Baker River Nor Wmrmrted 4 01.:anoizan Rfrcr Nor Wan"anrad ' Lake Wcnatcbcc Nor Wan·antcd 6 Quinah Lake Nor Wanm11cd 7 Lal:c Plca\tu1t .Vot lYarramed 8 Sacramcnto River Winttt•l\lll -f, d!w..,•r,'!J Chinook Salmon ' rYP~r Cohunbia River Sprinl!-n1.11 L,.J111i_,_u,.,,1 _. (0. uhai1:i1.1ch4) 10 Snal:c Rfrcr SP.!:!n~ 1Su11uncr•lllll 11 Snake River Fall-run --- 1' Pu2c1 Sow1d - 13 LowcrColumbin Rivn- 14 J:!~r Willarucl!c River --- 1' Ccnrral Val!~jprina-run 16 California Coa\tal 17 Central Valier Fall aud Late Fall•rnu S··t>cl,i o"Co11re,11 18 iJip_.ecr Klamath· T,init)'. Ri,·cr<, Nor Wmram,•d 19 O,·co-on Coa,t Not Wmramcd 20 Wa,hin<>lon C'oa>t Nor Wmnmtcd '1 Middle Columbia Rin, >P.rin<>-nu1 Nor Wmnmted " J::1p~r Columbia Rh-er \L1Um1er1fnll-nu1 Nor Wmrantl'd B Southern Ore1on and Northe111 California C'oMt Nol Warranted l4 De-.c:hute\ Rfrer \lllnmcrifol\.n111 Nor Warranted 25-Central Califomia Coo\t llirta.fl 1(d - Coho Sabnoo 26 Somhcm Om,oo'No1thcm Califo111ia -__ ..,. (O. kis11teh) " Lower Columbia Rh-er . Critical h.abitrn l8 On:11011 Co;,1,1 29 South\l'C\I Wa,hiu~ton U11de1ern1i11rd 30 ~lief Sou111i'S1rni1 of Oeol'pia S• tdt1 o(Co11rtrn 31 O!vmok Peninsula Nor Wmrnnttd Chum Sahuou 3l Hood C'an~I Suuuncr-nm = -- (0.keltl) 33 Colwnbia River 34 Pu11:ct Sound1Strait of Oeonria Not Wmrn111ed " Pacific C'OH[ Not W,m·antf'd 36 Sourhem Califomia {•·.!f!.!.!.!,-•"r,:ij Steclbead 37 ...!IPpcr Columbia Rini ·-(0. m1·kiu) 38 Central C'a!ifonria C'oMC 39 South Central California Coim 40 Snake Rh·er Ba>i.11 .,, -- 41 Lower Columbia R.i1·CT . " California C'eum'li \'all..v '·= 43 ~~r Willamcnc Ri,·er 44 Middle Columbia Ri\'Cr -----= " Northern Califon1ia 46 Oreo-on Coa~t SP._tt/n of Conrtr,i 47 S0uthwe1,1 Wa\11inpJon Nor Wmranred 48 ...Q1~r.ic Pcnilnul.1 Nor WmTanttld 49 Pu11er S01111d . Critical habitm ,0 Kla111..1rh Momuaim Prndnce Not Wan-onttd Pink Salmon '1 (0, gorb11sdra) Eve1l•Vcru· Not Warmntcd 52 Odd-venr Nor Warmnrcd The ESA define\ a "~pccic\·· to include any dl\tinct population \ep:ment of any ~pecle\ of Ycrtebratc fah or wildlife. For Pacific >almoo. NOAA Fi,hcrie> Ser.,.ice con\iden an e1·olutio11arily \ip:nificont unit. or "ESU." a -\pcde,·· uude,-the ESA. For Pacific \teelbead, NOAA FiU>.e,ie> Ser\'ice bl\\ delineated diuinct population ~epnenh (DPS\) for con\iderorion D\ "\pecie~·· under the ESA. 26 I I I I Ii II I ii II (i UI Ii II I I I I I I I I The project is located in T23N ROSE S02 & S03. Sections that Contain Natural Heritage Features I Data Current as of November 5. 2010 List of surveyed land sections in Washington identified by the Natural Heritage Program as reported to contain Natural Heritage Features. Contact the Washington Natural Heritage Program at (360) 902-1667 for more detailed information on locations and occurrences. I Town. Range Sec. Town. Range Sec. Town. Range Sec. Town. Range Sec. T22N R35E Sl3 T'23N R02W S14 T23N ?.09W S19 T23N Rl7E S04 T22N R35E S23 T23N R02W S15 T23N ?.09W S20 T23N Rl'?E S12 I T22N R35E S24 T23N R02W S16 T23N R09W S21 T23N Rl7E Sl3 T22N R35E S29 T23N R02W Sl7 T23N R09W S26 T23N Rl7E S27 T2ZN R35E S30 T23N R02W S20 T23N RCl9W S29 T:23N Rl8E S07 T22N R35E S31 T23N R02W S21 T23N R09W S30 T23N R18E SOB T22N R35E S32 T23N R02W S22 T23N R09W S31 T23N Rl8E Sl6 I T22N R35E S33 T23N R03W S03 T23N R09W S32 T23N R18E S17 T22N R36E S04 T23N ROJW S04 T23N R09W S38 T23N Rl8E S18 T22N R37E S26 T23N R03W sos T23N R09W S40 T23N Rl8E S19 T22N R39E S19 T23N ROJW SlC T23N R09W S50 T23N Rl8E S20 I T22N R3StE S24 T23N R03W SlE T23N RlOE S32 T'.::3N RleE S2l T22N R39E S25 T23N R03W S35 T2.3N RlOW SO! T23N Rl8E S22 T22N R39E S26 T23N R03W S36 T23N RlOW S02 T23N R18E S'.23 T22N R39E S35 T23N ROSE S25 T23N RlOW S03 T23N Rl8E S26 I T22N R39E S36 T23N ROSE S3E T23N RlOW S04 T23N RISE S27 T22N R40E S16 T23N ROSW S19 T23N RlOW Sll T23N Rl8E S28 T22N R40E S17 T23N R06E S10 T23N RlOW S12 T23N Rl8E S29 T22N R40E S19 T23N R06E Sll T23N RlOW S13 T23N Rl8E S30 I T22N R40E S20 T23N R06E S31 T23N RlOW S14 T23N Rl8E S31 T22N R40E S21 T23N R06W S17 T23N RlOW S36 T23N R18E S32 T22N R40E S29 T23N R06W S29 T23N RllE S15 T23N Rl8E S33 T22N R40E S30 T23N R06W S30 T23N RllE S35 T23N Rl8E S34 T22N R40E S31 T23N R07W S09 T23N Rl2W sos T23N R18E S35 I T22N R41E S01 T23N R07W S10 T~3N Rl2W S24 T23N Rl9E S07 T22N R41E S02 T23N R07W Sll T23N R13W S02 T23N R19E S18 T22N R41E S03 T23N R07W S14 T23N Rl3W S03 T23N Rl9E S2:?: T22N R41E S04 T23N R07W Sl5 T23N Rl3W S10 T23N R19E S27 I T22N R41E S07 T23N R07W S16 T23N R13W Sll T23N R19E S31 T22N R41E Sll T23N R07W S21 T23N R14E S01 T23N Rl9E S33 T22N R41E S12 T23N R07W S22 T23N R14E Sll T23N R19E S34 T22N R41E Sl3 T23N R07W S23 T23N R14E S12 T23N R20E S02 I T22N R41E S14 T23N R08E S01 T23N Rl4E S26 T23N R20E S03 T22N R41E S15 T23N ROBE S02 T23N R14E S35 T23N R20E S06 T22N R41E S16 T23N ROBW S07 T23N Rl4E S36 T23N R20E S10 T22N R41E S21 T23N ROBW Sl3 T23N R15E S13 T23N R20E S14 T22N R42E S03 T23N R08W S14 T23N Rl5E S24 T23N R20E S15 I T22N R42E S04 T23N R08W S15 T23N Rl5E S26 T23N R20E S31 T22N R42E sos T23N R08W S17 T23N RlSE S27 T23N R20E S32 T22N R42E S06 T23N ROBW S18 T23N RlSE S32 T23N R21E Sl3 T22N R42E S07 T23N ROBW S20 T23N Rl5E S35 T23N R21E S14 I T22N R42E SOB T23N R08W S36 T23N Rl6E S10 T23N R21E S17 T22N R42E S09 T23N ROBW S39 T23N Rl6E Sll T23N R21E S20 T22N R42E S13 T23N R08W S46 T23N Rl6E Sl2 T23N R21E S21 T22N R42E S16 TZJN R09E S02 T23N R16E S13 T23N R21E S23 I T22N R42E S17 T23N R09E S03 T23N R16E S14 T23N R21E S24 T22N R42E S18 T23N R09E sos T23N Rl6E S15 T23N R21E S27 T22N R42E S22 T23N R09E S06 T23N R16E S22 T23N R21E S28 T22N R42E S24 T23N R09E S29 T23N R16E S23 T23N R21E S33 T22N R44E S09 T23N R09E S30 T23N R16E S24 T23N R21E S34 I T23N ROlE S16 T23N R09W soo T23N Rl6E S31 T23N R22E S07 T23N ROlW S31 T23N R09W S06 T23N Rl6E S32 T23N R22E S27 T23N ROlW S32 T23N R09W S07 T23N Rl?E S01 T23N R22E S28 T23N ROZW S01 T.23.N R09W S18 T23N Rl7E S02 T23N R22E S31 I Washington Natural Heritage Program, PO Box 47016, Olympia, WA 98504-7016 I 27 I I I I I I I I I I I I I I I I I I DESIGN I EGENO Wf"?P-iwfa SEDIMENT RE~OVAL A.REA. 'JEOIMENT RE\.~QVAL NOTE· REMOVE SEDIMENT FROJ.J I - ~ VEGETATION REMOVAL AREA (22.J ALCOVES WORK AREA ------WETLAND BUFFER (110') STREAM BUFFER (165') Pl.ANTING MITIGATION LINE (15' BUFFER) EXISTING LEGEND TOE (BOTTOM) OF STREAM ----DRIVEWAY LINE --X -------FENCE ~ SURVEY CONTROL ----PROPERTY LINES R-0-W LINES ___ "4'_, __ DELINEATED WETLAND Stationing of the In Stream Willow Pruning for May Creek Station From Station To 0+00 0+30 0+70 1+50 3+00 4+50 4+90 5+40 7+50 9+80 10+20 15+00 PURFlOSE: REDUCE DURATION OF FLOODING ON PROPERTIES ADJACENT TO MAY CREEK; BEThtEN APPROX. RIVER MILE 4,J AND 4.9. OIREC110NS TO SJ TE: FROM COAL CREEK PARKWAY, (EAST Of 1-405) lURN EAST ON S.E. MAY VALLEY ROAD. GO TO 148TH AVE $.L, TURN SOUTH TO BR1DGE OVER MAY CREEK. DATUM: WASHING STATE LAMBERT GRID NORlH ZONE; NAO BJ / 91; NAVO 88 THE EXISTING TOPOGRAPHIC AND PHYSICAL FEATURES SH OWN ON TH IS PLAN ARE BASED ON A COMBINAT!ON OF FIELD OBSERVATIONS AND LAND SURVEY PROJECT TITLE: MAY CREEK DRAINAGE IMPROVEMENT SHEET TITLE: PLAN v1EW STA. o+OO -15+00 SCALE: 1" -200' ASSISTANCE BY: LINDSEY MILLER DRAWN BY: MEREDITH RADELL.A 29 ROPOSED WORK: REMOVE FlOW OBSTRUCTING VEGETA110N ANO SEDIMENT FROM MAY CREEK. PLANT 15' BUFFER OF NATIVE VEGETATION ON BOTH SIDES Of CHANNEL. ENHANCE Off-CHANNEL WETLAND FISH HABITAT DOWNSTREAIJ Of 148TH A S.E. SHEET: 2 OF B DA TE: FEB 3, 2011 ?.00 PURPOSE, REDUCE OURATION Of FLOODING PRO£CT TITLE, 0 zoo SCALE IN FEET SEDIMENT 3Etv:QYAl NOTE· REMO\'£ SEDIMENT FROM STA. 5+40 TO 7+50 SfA. 8+00 TO 26+26 ON PROPERTIES ADJACENT TO MAY CREEK; MAY CREEK DRAINAGE IMPROVEMENT ROPOSEO WORK: REMOVE FLOW OBSTRUCTING VEGETATlON AND SEDIMENT FROM MAY CREEK. PLANT 15' BUFFER OF NATI'£ >ECETATION ON BOTH SIDES OF CHANNEL. ENHANCE OFF-CHANNEL WETLAND FISH HABITAT DOWNSTREAM OF 148TH A S.E. BET\'.€.EN APPROX. RIVER I.IILE 4.3 AND 4. 9. DIRECTIONS TO SllE: SHEET lllLE: FROM COAL CREEK PARKWAY, (EAST OF' PLAN VIEW STA. 15+00 -29+00 l-405) lURN EAST ON S.E. MAY VALLEY ROAD. GO TO 148TH AV[ S.E .• lURN SOUTH TO BRIDGE O\IER MAY CREEi<. DATUM: WASHING STATE LAMBERT GRID SCALE; I" -200' NORTH ZONE; NAO 83 / 91; NA\/0 88 ASSISTANCE BY: LINDSEY MILLER DRAWN BY: UEREOITH RADELL.A 30 SHEET, J OF 8 DATE: FEB 3, 2011. I I I I I I I (I I • I I I I I I I I I I I I I I I I 11 I I I II I I ! I I I I • I -31n n 35 DO 30 00 25 00 20 00 15 00 10.00 5.00 ([ 5.00 10.00 15.00 20.00 25.00 JO.OD TYPICAL SECTION: SEDIMENT REMOVAL CUT ANO REMO\IE WUOW ~~~~~~~ilJW""'1f ,~ CHANNO.. LC,.V[ ~ ors It,,' -·· "n n ..... t" = iO' -'n -n 25 00 20 00 15 00 10 00 5. 10 ¢_ 5. lO 10 00 15.00 20.00 25.00 JO.DO TYPICAL SECTION: VEGETATION REMOVAL 1" = 10· ""' ---- -. -- bwSION CONTROL C 0TH PURPOSE: REDUCE DURATION OF FLOODING PROJECT 11TLE: 'ROPOSED WORK: ON PROPERTIES ADJACENT TO MAY CREEK; MAY CREEK DRAINAGE IMPROVEMENT REMOVE FLOW OBSTRUCTING VEGETA110N ANO SEDIMENT FROM MAY CREEK. PLANT 15' BUFFER OF NATIVE 'VEGETATION ON BOTH SIDES OF CHANNEL. ENHANCE OFF-CHANNEL WETLAND FISH HABITAT 001',NSTREAM OF 148TH AVfc S.E. BE1'1££N APPROX. RIVER MILE 4.3 AND 4.9. DIRECllONS TO SllE: FROM COAL CREEK PARKWAY, {EAST OF 1-405) TURN EAST ON S.E. MAY VALLEY ROAD. GO TO 148TH AVE S.E., TURN SOUTH TO BRIDGE OVER MAY CREEK, DATUM: AS STA TEO SHEET TITI..E: SECTION VIEWS SCALE: NOT TO SCALE ASSISTANCE BY: LINDSEY MILLER DRAWN BY: MEREDITH RAOELLA 31 SHEET: 4 OF 8 DAlE: FEB 3,. 2011 JOOO 2000 1000 10 00 20.00 JO 00 40 00 50 00 60 00 70 00 80 00 HABITAT MITIGATION ALCOVE GRADING I" = 20· I j,J_1 l)v LOP 1~8 lOD I -'C" II\~ w' ~~ I I "" ow ST Kl p -, .. 1\ I ,-0 ?.:_ ;.. ~ ES TO P= T ,- LO P l G C ROSS TOP OF LOG. NT IN Al.COVES AND CSE ~· ~ , I fi • 19 ~, mJ ....... , . ,. . " -WI ~ A 0 si '" ... = KE 80 00 oo,-. -20001 q_ 120 --,_ " 1-8000 h, fVU 12 .OQ H.00 HABITAT LOG MITIGATION PLACEMENT I" = 50' LWP INSTAl I ADON NOTES· THE FOLLOWING METHODS OR COMBINATIONS THEREOF WILL BE USED TO REDUCE MOBILllY OF LWD: EMBEDMENT OF 50 PERCENT SURFACE AREA OF LOGS AND WILLOW ANCHOR POLES TRENCH/BURY 60 PERCENT OF LOG LENGTH PINNING OF LOGS ANO ROOTWAOS BEHIND EXISTING TREES GREATER THAN 12~ DIAMETER IN COMBINATION WITH PARTIAL TRENCHING OF LOG PURPOSE: REDUCE DURATION OF FLOODING PROJECT TITLE: ON PROPERTIES ADJACENT TO MAY CREEK; MAY CREEK DRAINAGE IMPROVEMENT BETWEEN APPROX. RIVER Mil£ 4.3 AND 4.9. DIRECTIONS TO SITE: SHEET llTI.E: F'ROM COAL CREEK PARKWAY, (EAST OF SECTION VIEWS 1-405) lURN EAST ON S.E. MAY VALLEY ROAD. GO TO 148TH AVE S.E., TURN SOUTH TO BRIDGE OVER MAY CREEK DATU~: AS STATED SCALE: NOT TO SCALE ASSISTANCE: 8V: LINDSEY MILLER DRAWN BY: MEREDITH RA.DELLA 32 ROPOSEO WORK; REMOVE FLOW OBSTRUCTING VEGETATION AND SE01>.4ENT F"ROM MAY CREEK. PLANT 15' BUFFER OF NATIVE: VEGETATION ON BOTH SIDES Of CHANNEL. ENHANCE OFF-CHANNEL WETLAND FlSH HABITAT DOWNSTREAM OF 148TH A S.E. SHEET: 5 OF 8 DATE: FEB 3, 2011 I I ll i I I I I I I I I I • I I I i I I r L [ r l. C r - r • I ... r • r ·- r • ,_ r I • r \..- r L r L' [ ,...... l r L M111~T1QN PLAN ~QI£S CONTINUED (8) PL.ANTING NOTES 1. MITIGATION PLANTING PLANS REPRESENT A CONCEPTUAL PLANT LAYOUT. ALL MITIGATION PL.ANTING PREPARATION WILL BE DIRECTED IN THE FIELD BY THE ECOLOGIST. 2. PLANTING SHALL TAKE PLACE DURING THE DORMANT SEASON (NOVEMBER 1ST THROUGH FEBRUARY 28TH). PLANTING MAY BE ALLOWED AT OTHER Tit.AES AFTER REVJEW AND WRITTEN APPROVAL BY THE ECOLOGIST. 3. WITH IN THE FLOODPLAIN EXCAVATION AREAS AND ALL PLANTING AREAS WHERE REED CANARY GRASS HAS BEEN COMPLETELY REMOVED, PROVIDE AND INSTALL 4 INCHES OF COMPOST {PER SPEC) ROTOTILLED TO A (12) INCH MINIMUM. 4. IN ALL PLANTING AREAS WHERE REED CANARY GRASS IS PRESENT, FIRST MOW THE GRASS. COVER MOWED REED CANARYGRASS WITH CARDBOARD (OR A SIMILAR BARRIER MATERIAL AS APPROVED BY THE ECOLOGIST) FOLLOWED BY 6 INCHES OF COMPOST. 5. PLANT SHRUBS AND TREES THROUGH fHE CARDBOARD AND COMP0Sf AS DIRECTED BY THE ECOLOGIST. 6 . ALL PLANfS SI-W..L BE NURSERY GROWN A MINIMUM OF ONE YEAR. PLANT MATERIAL IS TO BE SUPPLIED BY COMMERCIAL NURSERIES THAT SPECIALIZE IN PLANTS NATIVE TO THE PACIFIC NORTHWEST. PLANT MATERIAL SUBSTITUTIONS ARE SUBJECT TO APPROVAL 8Y THE ECOLOGIST. 7. NO TACKIFlER, HERBICIDE, OR FERTILIZER SHALL SE USED IN THE PLANTlNG AREAS. (C} GENERAL NOTES 1. TO PREVENT REESTABLISHMEITT OF INVASIVE VEGCTATION, THE TOP 24 INCHES OF EXCAVATED SOIL IS NOT TO BE REUSED AS FILL ANYWHERE ON THE PROJECT SITE. 2. DO NOf DRIVE EQUIPMENT IN AREAS OF THE SITE WHERE COMPOST HAS BEEN MIXED INTO THE NATfVE SOIL. May Creek Riparian Buffer Planting, west & east of 148th Ave SE gggggg~gl Latin Name Common Name Size/Specifications Quantity Trees ......... R!Kl older 1" Coliper O 8-8' H•i'9ht 260 Ploot 9' O.C. he .... ~ Stkc t?Net :i 901 .• 5-6' Hoi91'1t Full o.r-,,., Fo1iQ911 260 Plont 9' O.C. P.,iw~ll'f'. Block cononwood 6° staole, lop on, 1" cl/ornet11r '"' "'""""" Plant 9• O.C. _,,,_ Wntem reel c;edor ::I Qd .. ~6' He/Qht Fun OenH Foi.oo, 260 Plant 9' O.C. Shrubs/Willows G:rrm: unr .. Rod-oiHr (!Qgwoocl Sore rq0l Ui11imum JS" LonQ ... Plant J' O.C. Sala~ Po,:ific willow Un st.okn, 6' lol"IQ, 1/2-1" 01Qr'lffl« ... Plo'lt 3• O.C. s..amd~ Sitlla •llo• UYfl Slokts. 6' L.on9, 1/2-1" Dicrnet.-... ~ Pla,t J' O.C. KlngCamy PURPOSE: REDUCE DURATION OF FLOODING PROJECT TlTLE: PROPOSED WORK: ON PROPERTIES ADJACENT TO MAY CREEK: MAY CREEK DRAINAGE IMPROVEMENT REMOVE FLOW OBSTRUCTING BET"h£EN APPROX. RIVER MllE 4.3 AND 4.9. VE GET A 11 ON ANO SEDIMENT 1-"ROM OIRECllONS TO SHE: SHEET TITLE, MAY CREEK PLANT 15' BUFFER Of FROM COAL CREEK PARKWAY, (EAST Of PLANTING NOTES AND TABLE NATIVE VEGETATION ON BOTH SIDES 1-405) TURN EAST ON S.E. MAY VALLEY OF CHANNEL ENHANCE ROAD. GO TO 148TH AVE S.E., TURN SOUTH OFF-CHANNEL WETLAND FISH TO BRIDGE OVER MAY CREEK. HABITA1 DOWNSTREAM OF 148TH AVE DATUM: AS STATED SCALE: NOT TO SCALE S.E. ASSISTANCE BY: LINDSEY MILLER SHEET: 7 OF 8 DRAWN BY: MEREDITH RAOELLA DA TE: FEB 3, 2011 33 ..... ,., :J 35 . • ! :! J ' .. '! " •• : •• • • R ; : --:· :··f:1t·(:.; ~', ..... , ... " ..... · ·I I : ' f ' ' ' B . I ,, ·:' ' ' i we..,;. i4 ...... ---.. o) 36 I \ ... ] .. \' . '---...\ I I .. I I i n ,_ I ' _j _J "' I ' -.. ...1 ,- ,.-. I I I I I I I I I I I I I I I I I I I I e . . !' ··i i-• a ~ - 35 ~ I~ ~ ~ ! i w n " " ~ I c • E C { ' < i H ' ~ i ~t-+-+--\-t--1 I 1 ~ \ ~~ ' ) I , . '. I I - w °' · Brnrtnl ~ll ~---:-----=.::.::..::.::..= ~~ YJ· ' ~~~--· .......... ~:fif*"" ~>;,_£[ I """" . , I 'l' . ---J~-~-1-·· ··L~. "····]···"··[--·· ··\··-.. . : .. : .(I -.••. 'IOU,l,to,PLICO,l!)(I.S!l(Ml,I •. IS SC!£11,1.'11:: ~ IH$ , lll'/Uf.•D:N;f~· $PmtS -OJ,Wf,fe .u 1!11: tf;!DMNal 1/(J -ll;t'fO', ,..., ,,.., "'" ... ... 4.m 24) t :t.00 •.m .., ... ,om 12.ao 14.eo II.Ill) 10.00 LONG MARSH CREEK TYPICAL CHANNEL SECTION ffl a::, " ~ ----...,__ .//~>-:;::~-~=-~ -,, . ' ~· ', --// : -(WIJ ...... --/ . ....... ~/ : Teo. 1::= __ , .... , -· ~ 1----,_ --~~, --~ , .:-,,., ___ :::.-P::39! ,; """' -- .. ,_ -- fiiQ -iiiil - SIDE ~H'i'w.fr~E:ECTION "' --··~ ~ -- ill ·<> ~ - Ml~~------------------ --- - . L~--. . __ _;,_ ---;--- .CJlU. 2 WCA<:N3 PAYS -11 .. _ ....... ,..,..,_...;_J LCNO MARSH CfEB RES'fOFIATION "'"' C4 ~ 8 """ ""'°"' '""" 2006-42 ---= = ~ King County Department of Transportation Road Services Division Engineering Services Section Environmental Unit King Street Center 201 South Jackson Street Seattle, WA 98104-3856 (206) 296-6520 Fax (206) 296-0567 TTY Relay: 711 www.metrokc.gov February 9,201 l TO: Doug Chin, Senior Engineer, Water and Land Resources Division, Department of Natural Resources and Parks FM: Julia Tumey, L.G., Environmental Engineer, Environmental Unit, Road Services Division, Department of Transportation RE: and Jeff Burkey, Hydrologist, Water and Land Resources Division, Department of Natural Resources and Parks May Creek Drainage Improvement Project: SE May Valley Road and 148th Avenue SE-Sediment Assessment Introduction This memo provides information on sediment conditions in May Creek from approximately 148 1 h Avenue SE upstream to 1641h Avenue SE. This evaluation addresses geomorphologic controls, sediment sources, sediment behavior in the drainage and how the project actions are likely to influence future sedimentation in May Valley. The purpose of the following background evaluation is to provide information to assist King County Department of Natural Resources and Parks, Water and Land Resources Division in the design process for a drainage improvement project in May Valley. The proposed project location is shown in Figure I. Two questions have been raised regarding sediment associated with the May Valley drainage improvement project: Question I: Will the project change sediment delivery downstream to May Creek? Question 2: After the proposed drainage improvement project and mitigation on May Creek in May Valley, will sediment refill the May Valley project area? I I I I I I I I I I I I I I I I I I I May Creek C h a nnel Restoration Project Project Vicinity e StudyArea o Mile Markers • stream Incorporated Areas Cougar Mountain Wildland Park N + March 2010 lQ King County 0 95 190 IBO .. 1111111111:::=::=::111 ...... c:::::=::::i Fee 380 570 Th• J•h'Nltion Included on tNs map h• bNn oomple:d bf ~ Cour1--ttllttrom •Volrietyol souro. •nd IJsiA>jed.to "'---Ki-la COWi¥ ~-no,.,.ueruloN or-..,r.cks;, optMS Of n,pled, • to •oc1.Hc1J. oompW:.-.es-s , ~ • ._ or rigNs 1D the we olsuoh intonn.ilon. This dowmerfis not ftendtidb 1.ae a ,1.surv4¥ptocad. ~ C°"'yshll not bo LIDltb •"Jll"'*•(1pooi,I, indr•ct. lnddtrt«, Of oons~nti,I dMNa• lndudn9-but natlff'itad t o_ lcst,wanua o, klstp,oas ruulnetomthe w:e o1nw1.se d ~•i*mwtion ~d onfl• m,p Anfsaleofths nupor infromubon ontt. m1ptr pfo~ •-=-pt t¥ ... .., parmiuion o1 f0'8 c~ F igu r e 1 ~•-d-11tnu11t:u '11 1tfQ.a,c c Doug Chin February 9 , 2011 Page 3 There are a number of factors that were not available for the assessment: • The actual suspended sediment loads in May Creek in the project area, the suspended and bedloads from the tributaries and the relative contribution of sediment from different sources are not known. • The change in sediment loading over time due to changes in land use in the basin; logging, development, agricu ltu re and channel dredging is not known . • All of the tributaries provide some amount of sediment to May Creek within the valley but the actual volume is not known. Long Marsh Creek delivers gravel to silt s ized sediment to May Creek. A depositional area of gravel and sand is visible in May Creek. Estimates of the delivery rate for Long Marsh are made from surveyed elevation changes between a sediment-removal project in 2002 and 2010. • Beaver dams above the project area trap sediment and release sediment periodically due to flooding or breaching. An assessment of the sediment behavior presented here is based on published basin information, aerial photo interpretation, survey data from 1965, 1979, 1993 , 2002 and 2010, a soil-loss analysis by Jeff Burkey, sediment samples from the May Creek channel, and May Creek survey records and studies conducted for the project. This assessment provides a working hypothesis about sediment movement in the valley and the basis for future investigations. Background Geology and Stream History The wide and relatively flat May Valley (RM 3.9 to RM 7.0) was created by glacial ice melt runoff and is part of the "Kennydale Channel". The valley is underlain by recent alluvium over recessional outwash deposits and compacted glacial till. These deposits overlie Eocene Tukwila Formation . The formation is composed of volcanic tuff, fine- grained volcanic sandstone and volcanic tuff-breccia. The formation is reported to outcrop west of 146th and forms a physical boundary between the downstream ravine and May Valley upstream. The geologic map is shown on Figure 2 . The creek gradient within May Valley is 0.2 percent and the valley is predominately a depositional environment. Aerial photography and Lidar image of the valley show evidence of pre- dredging channel meanders. Historic survey mapping from 1872 shows May Creek as a meandering stream and Tributary 0291 a extending north to join May Creek just south of Indian Meadows rather than the current confluence approximately 1,440 feet west of 164th Avenue SE. The alluvial fans from lndjan Meadows and Long Marsh Creeks appear on the 1872 map and the mapped location of May Creek is routed to the southwest around the higher elevations of the Long Marsh/Indian Meadows alluvial fans . The historic channel map for 0291a is consistent with Lidar images showing meander scars in the valley. (Aerial photos and historic map information is located in Appendix A). May Creek was dredged to form a linear channel between 1910 and 1936 (Foster Wheeler, 1995). A description of May Creek by Bretz (1913) describes May Valley as a "swampy, wide bottomed old channel". A project plan dated 1935 (King County Map Vault) shows creek modifications extending from Lake Washington to 164th Avenue SE. I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I May Creek, May Valley Legend Ow-Wetland Deposits Organic Rich Sediment Qvr-Recessional Outwash Deposits Sand and Gravel Qvt-Vashon Till Compacted Mix of Slit Sand and Gravel Tpt-Tukwila Formation-Mix of Volcanic and Sedimentary Material 105 0 10 20 30 40Miles ------ N ,\ T Figure 2 tQ King County Doug Ch in February 9, 2011 Page 5 Aerial photos from 1936 show the May Creek channel cut as approximately 25 to 30 feet wide as measured from the aerial photos . The photos clearly show the channel excavation boundaries. The c hannel is uniform with limited shrubs or trees. Periodic dredging is reported during the 1940s through 1960s (Foster Wheeler, 1995). Property owners may have removed sediment periodically. Sediment Sources to May Creek Agriculture and Pastures In tbe immediate area of the proposed project there are roughly 8.4 hectares of active animal pasture that abut the stream on both sides with a few animal access points to the stream water (assumed watering holes). Under existing conditions, these animal pasture areas are flooded at stream flows b elow mean annual flow rate (8.6cfs)-over-bank flooding begins approximately at 6 cfs at the low point in the bank. Thus, its likely sediments that may not have washed off during a rain event with overland flow will be washed off when the stream-system capacity is exceeded and floods overbank. After a flood event, there does not appear to be any visual deposition of sediments resulting from the stream itself and upstream conditions but erosion rills are present in tbe pastures . Thus, it is assumed that sediments suspended in the water column that flush into the pasture retreat back into the stream system. Given this condition with the added animal activity, sediments from soil disturbance would be additive to upstream sediment loads , thus increasing sediment loads downstream. The proposed project goal is to reduce frequency of pasture flooding, thu s sediment loads, from a frequency of any appreciable storm to a near one-year storm frequency . To assess potential sediment loads from pastures in the proj ect area, similar studies in the Green River watershed were evaluated (King County, 2007). The Green River studies have estimated sediment loads (via total suspended solids) ranging from 50 to 170 kg/ha/yr; residential = 158 kg/ha/yr, commercial = 172 kg/h a/yr, forest = 110 kg/ha/yr, and agriculture = 50 kg/ha/yr. Literature values (Burton and Pitt, 2002) are significantly different with 10, 420, 3, and 343 kg/ha/y r for residential, commercial, forest, and agriculture, respectively. Monitoring station s used for agriculture land use in the Green River watershed study were downstream of pasture lands in ditches that had significant amounts of choking vegetation in them just upstream of the sampling station. Given the relative position of the sampling location and the proximity of vegetation upstream, one may expect the Green River sediment loads to be lower than expected because of the vegetation trapping wash-off loads . Co nsequently, estimated loads from the May Valley pasture areas are then estimated in the range of 50-340 kg/ha/yr (assumed 200 kg/ha/yr average). Simplistically if we estimate loads from the pasture lands to be 200 kg/ha/yr, and post-project loads are reduced in half, then for a ten-year period and 8.4 ha, there is a reduction of 8.4 metric tons of sediment contribution to May Creek. An estimated range would be a reduction of 2.1 to 8.4 metric tons of sediment contributed to May Creek. I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I , I Doug Chin February 9, 2011 Page 6 Hydraulic model results estimate that the channel capacity to carry bedload and suspended sediment through the project area will be increased after the proposed project by increasing the channel efficiency. Velocities associated with lower flow rates are increased with the removal of vegetation choke points in the channel along with channel- bottom high points that otherwise create backwater conditions conducive to deposition, while depths are increased with a lower channel bottom in conjunction with more water kept in-channel rather than over bank because of improved flow-rate capacity. Reduced overbank flooding into reed canarygrass may allow the annual volume of fine sediment and muck moving downstream to increase on a yearly basis. Higher flow or flood events would continue to carry stored in-channel and off-channel fine sediment downstream in a larger pulse, rather then metering sediment at lower flows. The cumulative total volume of sediment over a longer time frame, ten years for example, would not be expected to change. May Creek bottom sediments were sampled by the King County Department of Transportation Materials Laboratory (King County, May 20 IO and October 20 I 0, Appendix B). In the area of 1461 h Avenue SE the channel bottom is composed on sands and gravels, to well-graded gravel. Larger gravel, cobbles and occasional boulders are also present. In the relatively flat and low-gradient portions of May Valley in the area of 1481h Avenue SE the hard channel is composed of silty-sand and sandy-silt. At the confluence with Long Marsh Creek the hard-channel bottom is composed of well-graded gravel. A variable layer of semi-liquid, organic rich mud (herein referred to as muck) is present within the stream channel behind constrictions in the channel (Figure 3). The muck was sampled 25 feet upstream of a private bridge at RM 4.6. A modified Loss on Ignition analysis (LOI) was performed on the sample and the organic content was approximately 28 percent. This is a very high percent organic material compared to King County streams (Burkey, personal communication). The exact source of this high organic content is unknown; however, the tributary stream channels within the project area do not contain the same muck material and the most likely sources are pastures, agricultural fields and grass/tree litter within and above the project limits. Sources of Stream Sediment Most of the major tributaries to May Valley enter May Creek upstream of 164 11 ' or downstream of 146 1\ outside of the project area. From just below 1481 h and 1641 h four tributaries: an unnamed tributary (0291a), Indian Meadows (0291), Long Marsh Creek (0289) and Greenes Creek (0288) enter May Creek. Small alluvial fans occurring at the base ofTrib. 0291a and Indian Meadows identify where sediment is deposited at the valley floor. o A ditch carries Indian Meadows Creek to May Creek. The ditch carrying Indian Meadows has piles of sediment adjacent to the ditch. These appear to be hand dug sediment piles removed from Indian Meadows Creek (Bauman, personal ----------------------------------------------- Doug Chin February 9, 2011 Page 7 communication). Finer sand and silt reached May Creek and the confluence with May Creek is clogged with silt and reed canarygrass (GeoEngineers, 2008). o Tributary 0291 a is shown on the l 872 map and before development of the valley flowing northwest parallel to May Creek, joining May Creek near the confluence with Indian Meadows. The stream now joins May Creek downstream of 1641h and is hydraulically controlled by a culvert under SR-900. Sediment is primarily deposited upstream from the culvert (Foster Wheeler). The creek lacks a defined channel above the confluence with May Creek. o Greenes Creek enters May Creek west of 148 1h Street and currently does not contribute significant sediment to the project area because Greenes Creek discharges to a wetland and the confluence with May Creek is choked with reed canarygrass. Table I: Two year flow for May Creek Tributaries in the Project Area (Foster Wheeler, 1995). Drainage Unnamed Trib. Indian Long Marsh Greenes 0291a Meadows 2 year flow in 23.8* 17 42 26 cfs *USGS StreamStats Estimate Within the project area, Long Marsh is one of the largest flow (Table I) and sediment inputs. The Long Marsh sediment deposits constrict flow and muck movement in May Creek. Long Marsh Creek joins May Creek south of May Valley Road near 150th Place NE. Aerial photography from 1936 shows the creek in a relatively straight channel. The current channel is on the order of two (2) feet wide and several inches in depth at winter low flow. The stream banks are approximately one foot in height, and the surrounding floodplain/fan surface is primarily planted in pasture grass with some recent native plantings. Evidence was found of gravel deposition throughout this reach. Discussions with earlier property tenants indicate that sediment deposition extended into the adjacent pastures following a January 2009 storm event. Long Marsh Creek deposits form an alluvial fan composed of cobble-to silt-sized particles and discharge silt, sand and gravel into May Creek. May Creek channel bottom elevations are higher near the confluence and this channel fill is a choke point for flow within the channel. During high-flow events, Long Marsh carries large gravel-sized sediment to May Creek. Before Long Marsh was straightened, the stream would have migrated across the alluvial fan as sediment was deposited in the stream channel. As noted in the previous section, the Long Marsh and Indian Meadows alluvial fans built out into May Valley and forced May Creek around the fan. I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Doug Chin February 9, 2011 Page 8 May Creek Channel Changes with Time Horizontal Boundaries Aerial photos from 1936 show the May Creek channel cut as approximately 25 to 30 feet wide as measured from the aerial photos. The photos clearly show the channel excavation boundaries. The channel is uniform with limited vegetation. Foster Wheeler measured the mean May Valley Creek channel width in 1995 as 20 to 25 feet, with wider sections up to 60 feet at RM 5.6 (Foster Wheeler, 1995). In March of2002 a stream survey was conducted between 164 111 Avenue SE and 148 1h Avenue SE (O'Rollins, 2002) and measured the average channel width at ten to 14 feet. A stream survey was conducted in 2010 (Thompson and Bauman), and the average wetted width of habitat units was approximately 12.1 feet and the widest wetted width was 23 feet (surveyed reach RM 4.35 to RM 4.87). While no change in average width occurred from 2002 to 20 I 0, there is a possible pattern of channel narrowing between the 1936 and 1995 and comparison between the 2002 and 20 IO stream surveys. This is reflected in the available measurements; especially in areas dominated by reed canarygrass. The channel is still a relatively straight excavated ditch but grass, shrubs and trees have encroached into the channel. Survey data from 2002 and 2010 surveys are also available. Cross sections of May Creek are shown in Figure 4 (cross section locations are shown in Figure 5). Five cross sections were chosen to compare the stream channel at relatively fixed locations in the stream. Upstream of the road bridge at 148 111 Avenue SE the channel is narrower and slightly shallower (Section B-B). Downstream of the bridge the channel is wider and more uniform in shape (Section A-A). The cross section at Long Marsh (Section D-D) shows the 2002 bank deposits (right bank) associated with excavating sediment from May Creek (private property owner activity) and the filled-in 2002 channel profile from Long Marsh Creek deposits. During the 2002 pilot excavation project in May Creek at the Long Marsh confluence, sediment was removed to approximately elevation 309. The left bank (looking upstream) has now filled in to 2002 elevations at the confluence but the rectangular channel shape is still present on the right bank. Upstream of Long Marsh Creek, the channel is approximately the same width but shallower. This may be due to where the survey staff was placed and the CAD program interpolating between points. Downstream of Long Marsh Creek the channel has narrowed. Survey locations varied slightly between center line, right bank or left bank and cross section elevations are approximate. I I I I I I m ;:: • s· " " • D , , .. Q ~ • , 0 fl • 3 ll I I I I I I ~ I ~ Elevaliai (ft) w w w w w NO 0 0 ,;; N NO ~ 0 g I 4.182058xs -4.1~ I / ,r "-' ,, I \ 4.26.5343 Do'Mlstream of Rock Weir I ','' 4.278nO Do'Mlstream of 146th Brid .. "'--.'..._ ~- ' I ~~ 4.310823 KC Su,vey year 2010 ~ 4.323418 ' ' . j _ __.:_-~ .-, '< ~ j-4.353836 KC Survet year 2010_ () o 4.369331 KC Survey year 2010 ii 0 • "" 4.387575 KC Survey year 2010 m 4.411003 I .. ~ 4.426539 KC Survey year a:110 ~ 4.445406 l ' ---~ ~ "' 4.455 Bl'i(tJe #3 148th () 4.4n884 KC Survey year 2010 (similar to OTA .. 0 ~ 4.482002 KC Survey year 2010 0. 4.505452 I " ci' ~ ~ 14.532274 z g "4.551ffi8 ,, ~ 4.575359 KC SUIVey Y8'.3f 2010 ' co co ' ' 4.600738 ;,,._ 4.622613 -='-" -, ;:: 4.640315 / • ;; , '1', ,! I ;;; , • I , i~ 4.708732 KC Survey year 2010 (similar to OTAK X ... ,_ / . ;,; N 5· (' l': . . '( -~ U) A 0 3 () 0 4.749514 KC Survey year 2010 (similar to OTAK XS ... z . I \ ,, I ' -4.788456 KC Survey year 2010 (similar to otak xs . \" , I / ' ~ 4.828$0 KC Survey y~r 2010 (similar to otak x .. ' ' C, // " 0 4.861266 , ~ 0 4.887389 ~ i 4.912045 K.C Swvey yea, 2010 (similano otak x,,', .. ~ ;,; g 4.93111s . I : ,n 4.949111 KC Survey year :a:>10 (similar to olak xs . U) 4.900724. I () z 4.988154 I ~ " ,, w 5.038938 otak xs 7515 I I ~ !\' " ,) C, 5.04 focttridge Ul'.5lrmm of C~lasurdo property '3 I I I 0 ' 0 ~i 5.097[()3 otak xs 7875 0 ' I I 0 I \ 5.1 :J:1954 otak xs 8005 ' 5.185707 otak xs 8315 I A" \' ,\ LL ~, ;ol rj~j • 2.0109.'i ~ colrolg, a ? I I fl, ·(no1oz 'A1uno::i gU!)I mo1,:1) OJOZ u! ssou:,p141 )UOU!tpos~onw pue UO!)UA0[3 monos 1ouun4:) l!U!M04S Ol!.JOld ~001:) AUW £ amll1,:1 6 ollnd O I OZ '8 1oqmoooa U!4::> llnoa I I I I I I I I I· I I I I I I I Doug Chin February 9, 2011 Page 10 Channel Bottom Elevation Channel elevation surveys were conducted in 1965, 1979, 1993, 2002 and 2010 (Data is located in Appendix C). A profile of May Creek channel from just below 148'11 Avenue SE to approximately 1,300 feet upstream of the confluence with Long Marsh Creek as shown in Figure 5. The figure compares the 2002 and 20 l O survey profiles and gives spot elevations at the 148'11 Avenue road bridge and at the horse-crossing bridge on parcel 0223059091, 15019 SE May Valley Road from 1965, 1979, and 1993. Upstream of Long Marsh, between 2002 and 2010 the hard channel bottom is a foot lower in some areas and a foot to two feet higher in others. At the horse bridge the elevation has varied from 307 feet to 311 feet associated with sediment deposition from Long Marsh Creek. From station 11+00 to 8+00 at 148 111 A venue, the channel profile has flattened and the channel bottom has shallowed approximately three feet. This area coincides with thick areas of reed canarygrass. Between 1965 and 20 I 0, the 148 111 Avenue road bridge channel profile has stayed relatively consistent at 307 to 308 feet. It appears from the elevation differences that where the muck and vegetation builds up, the channel bottom has also been aggrading. Changes in the bottom elevation should be considered approximate, perhaps within a foot of elevation change. Survey elevations have not been taken at the exact same locations and stationing is different between projects. Stream profiles in 2002 and 2010 (Figures 4 and 5) show thicker areas of muck build up behind higher elevations in the channel. Up to four feet of muck was measured above the Long Marsh Creek confluence in 2002 and three feet in 20 I 0. Stream and elevation survey data indicates that soft muck present in the channel varies in thickness by location and with time. The muck thickness is variable and transitory, building up in the channel until higher flows in May Creek are able to move the sediment downstream. Muck and fine sediment is moved downstream by May Creek within the valley as bedload and suspended sediment. However, the valley and May Creek above May Valley is not the main source of sediment to Lake Washington. The May Creek Current and Future Conditions report (1995) identified the major source of sediment to the May Creek delta in Lake Washington as the May Creek canyon and eroding channels of tributaries that enter the mainstem downstream of May Valley. ,;,~ Cj 320 320 3101· 3001 -100 ,;_2010 . CHANNEL ~2002 :CHANNEL ------\\I tr .. Jo t sb SECTION A-A STA. 7+00 DOWNSTREAM OF 148TH ST NTS ··1310 ,1300 1 0 CD ..___., .--2002 --------,--------i-------;=:==~~:;:;~~320 320 . CHANN~ :2010 '.CHANNEL ? ,- 3101· · • · · "-\ +)./. · .. · ·····1310 3~~1oo Jo 6 ?o 16~00 SECTION B-B STA. 8+00 UPSTREAM OF 148TH ST NTS ffi ..___., MAY CREEK CHANNEL RESTORATION FIG. @1 CROSS SECTIONS 320 320 2010 CHANNEL ?002 ~HANNE.k-,-- ~-c 3101· "·I· 3001 -100 Jo t ~o SECTION C-C STA. 15+00 DOWNSTREAM OF LONG MARSH CREEK NTS ·1310 ,1300 1 0 CD ..___., 320r------~---=::::~~-r-------;=c=;,;,.,~-~ c:::= 2010 l r-.. 2002 J320 CHANNE!L / : CHANNEL 310•· 310 3 ~~1oo Jo 6 ~o 16~00 SECTION D-D STA. 16+00 LONG MARSH _C_REEK NTS ffi ..___., 320 320 310 3001 -100 NOTE, Jo t 2010 CHANNEL SECTION E-E STA. 17+00 sb 2002 CHANNEL UPSTREAM OF LONG MARSH CREEK NTS ALL CROSS SECTIONS ARE CREATED LEFT TO RIGHT LOOKING UPSTREAM. ·•310 ,\300 1 0 (5\ ..___., I I I 1· I I I I I- IJ I 'I, I I I: I I I I MAY CREEK CHANNEL RESTORATION FIG.[!] PROFILES 39 390 385 -380 375 ·370 365 ·360 355 ·350 345 -340 335 -330 325 -320 315 ·310 305 ·300 295 290 285 ·280 35 APPRoX: iii.v,iioii (lf .. !MVtK-~Ar(.FLOWi;JN~·· ~ ···$EE OEj"AI~ ·,-: ~;~ 1···· I :_ 1_ :_ L_: ........ ~-~--L~-~ .... ~~J·~·~: ········~~J·~·~:-· : ... L ... = ...... :~J·~-~~ ······--~~-~-[~~--:,Jnn: ·--~~r~~:·" ··-··:~~I~~:·· :1R±nn: ········:1~T~-~-:?nin~ :?1±nr: :??in~ :?~±on: :?4±0~ :7 .. ±n~ :?f-1,; :77±00: :?R±~ :,91&~ 335,--~~~~~~-,-~-,-~.,--~,----~.,--~,----~,------,~---,~--,-~---,~--,-~-. 335 330 330 325 325 320 320 315 310 305 L 20,o . __ . _ I ~M'PROX .. EllYATION CffANNEL. £?.Obi · ~ OF MUCK ~T FLOWUNE . CHANNEL . _.......... . . .. 310 .. ::.z.:277 7777777/ ( ( /7///7/(710'.' ( . 305 315 300 300 295 295 290 8+00 9+00 10+00 11 +00 290 \11111 0 I 10 • 120 SC"1...E IN FEET DETAIL 1 SCAf...E: 1"=40' ., 0 ,.l] II II II SCALE IN FEET 335 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~....-,335 330 325 320 315 310F:'~-_;_ -:_ 305 300 295 16+00 17+00 APPROX. ELEVATION: · .. r.2010 · "OF"MtJCf<" AT :FLOWUNE · · 11 ·J -_C:NEL ·. , ·)-~ ;- 18+00 19+00 330 325 320 315 310 305 300 295 20+00 21+00 22+00 23+00 II II ll .~] 40 0 40 80 SCALE IN FEET DETAIL 2 SCAf...E: 1"=40' I I I I I I I' I I, I I I I I I I I Doug Chin February 9, 2011 Page 13 Findings: Project Features and Estimated Results Pre-project May Creek Sediment Sources and Channel Behavior above the May Creek Ravine: Based on field reviews of the project area, stream report (King County, 2010), a literature review of past reports on the May Creek basin, and a review of aerial photographs a qualitative estimate of sediment sources has been developed. Sediment entering the project area comes from: • Upstream May Creek ( east of 1641 \ Most of the major tributaries enter May Creek above the project and therefore will be a contributor to suspended sediment in the Creek. Six beaver dams are present or have been active in the past above the project area; two below 164 1h and four upstream of the project. • Long Marsh Creek is a contributor to channel fill by sand, gravel and small cobbles. The larger materials are able to reach May Creek during high flows due to the straight channel, slope and past channel maintenance by property owners. • Indian Meadows Creek is a minor drainage that is partially ditched through a pasture that reaches May Creek and contributes sediment to May Creek. • Tributaries (0291 A, 0291) contribute minor but unknown amounts of fine sediment. • Stormwater runoff and pasture flooding contributes an estimated .2 to .8 metric tons of organic material and sediment to the stream. The May Creek channel is essentially a ditch, excavated in a historic wetland system prior to 1930. The gradient in May Valley is very low and the creek is only able to transport clay to sand sized sediment. • The May Creek channel stores organic muck/sediment from pastures behind relatively high spots in the channel bottom and releases it downstream to the ravine during higher flows. Muck then builds up again as flows recede and during rain events. Some of the muck contributes to aggrading the channel bottom as it is trapped and entrained by vegetation. The May Creek project proposes a number of features to reduce sedimentation to May Creek and channel filling. The 70% design plans include: • removal and control of reed canarygrass (Phalaris arundinacea); • native plant buffers along the banks; • reducing overbank flooding; • selected removal of vegetation from the channel downstream of ! 48'h Avenue SE; • excavated alcoves adjacent to the channel downstream of 148 1h Avenue SE, • a sediment management design for Long Marsh Creek, the primary source of sediment and channel constriction in the project area. These features are expected to produce the following results: • Removal and control of reed canarygrass will slow channel narrowing and infilling due to growth during spring and summer during low flows. ---------------------------------------------- Doug Chin February 9, 2011 Page 14 0 Adding plant buffers on either side of May Creek will shade the banks where reed canarygrass is present and help control grass growth and encroachment. 0 Reducing over-bank flooding of pastures will reduce the amount of sediment and organic material being carried to the creek by an estimated .2 to 0.8 metric tons per year. 0 Improved channel hydraulic efficiency will improve and move fine sediment and organic material that reaches the creek downstream, reducing the amount of sediment trapped in reed canarygrass above 148°1 Avenue SE. 0 The proposed alcove excavation and planting areas west of 148'" A venue SE will allow the creek to overflow into the alcoves during higher flows; this will slow the current velocities and minor amounts of sediment will drop out of suspension, but the amount of deposition is unknown. 0 The May Creek channel is likely to be both a depositional area and a source of suspended sediment during higher flows. Soft muck in the stream bottom above the confluence with Long Marsh Creek is a combination of organic material from pasture runoff with mineral sediment. The muck builds up in the channel after rain storms and floods and is moved downstream during higher flows. Reducing flooding within the project area will help reduce the build up of muck in the channel. 0 A mitigation project in Long Marsh Creek will intercept gravel and large sand-size sediment reaching May Creek. 0 Bank stabilization with jute netting and seeding will reduce erosion and sediment input to May Creek after excavation. Estimated Changes in Sediment Transport and Channel Dimensions after Drainage Improvement Project: The proposed project elements and existing conditions were evaluated for how sediment would enter and move within the project area. lfno change in behavior was expected, the conditions were assumed to remain the same and are listed below as "constant". If the project element was expected to modify sediment behavior by qualitatively reducing the amount of sediment reaching May Creek, a reduction is noted in the bulleted list below. During construction, temporary increases in sediment are possible and this is noted. ° Constant Upstream May Creek (east of 164'"). Most of the major tributaries enter May Creek above the project and therefore will continue to be a contributor to fine sediment in the Creek. Beaver dams will hold back sediment and periodically release it when breached. ° Constant Tributaries (0291A, 0291 and Indian Meadows Creek) contribute unknown amounts of fine sediment. These are expected to be minor. 0 Reduction Small proposed mitigation alcoves downstream from 148th will allow sediment to deposit at higher flows. 0 Reduction Long Marsh Creek mitigation project will minimize course sediment reaching May Creek and channel infilling. 0 Reduction Reduced pasture flooding will reduce the organic material and sediment discharged to the stream, estimated at .2 to .8 metric tons. I ,, I I 1· I il I fl I Ii I I I I I I I I I I I I I I I I I Doug Chin February 9, 201 l Page I 5 a a a Reduction Reduce channel narrowing by controlling recd canarygrass along the banks by establishing a buffer of plants on either side of the channel and shading the banks. Temporary Increase Channel excavation will temporarily expose "raw" bank and channel sediments to the channel. Jute matting and bank planting will control erosion but minor erosion within the channel may occur as the channel stabilizes. Change in fine sediment movement Fine mineral and organic sediments that reach May Creek and are now stored in the stream channel or trapped by grass during low flows will move downstream during lower flows. Fine sediment and organic material currently stored in the channel and moved downstream during high-flow events, will move downstream at a constant rate rather than episodic rate. The overall estimate is a net reduction in fine sediment and organic material reaching May Creek within the project area. Long Marsh Creek mitigation, the mitigation alcoves, reduced flooding, and reed canarygrass control are project features that decrease sediment contributions to May Creek in the project area. Controlling willow and reed canarygrass will control channel narrowing. Responses to Questions on Project Performance Question 1: Will the project change sediment delivery downstream to May Creek? Response: The May Creek Current and Future Conditions report (Foster Wheeler, l 995) identified the major sources of sediment to May Creek as coming from the ravine and tributaries below May Valley. The hydraulic analysis (King County, 20 I Oa) shows that changes in flow velocity below 143rd Avenue SE are negligible. Sediment movement is controlled by flow. Therefore, the same size sediments would be moved within the May Creek system. Muck sediments are currently stored behind topographic highs in the stream channel and are moved downstream in pulses during high flow events. In general fine sediment that does enter the creek as bedload or suspended sediment will move downstream due to improved channel efficiency rather than being stored in the creek channel above 148th, incorporated into the banks and moving though during large flow events. However, some fine sediment or muck that does enter the creek will continue to be stored behind topographic highs in the channel or in topographic lows above and below 148 1h Avenue. We estimate the project-related reductions in sediment delivered to the creek primarily from reduced overbank flooding, will reduce the total fine sediment and organic muck in the stream. Question 2: After the proposed drainage improvement project and mitigation on May Creek in May Valley, will sediment refill the May Valley project area? Response: We estimate that there will be an overall reduction in sediment contributions to May Creek within the project area. The stream channel bottom elevation is relatively stable, except where Long Marsh Creek discharges to May Creek and where reed cannarygrass and muck aggrades the channel. Reducing sediment and organic matter input to the channel from Long Marsh Creek and the pastures and removing reed Doug Chin February 9, 2011 Page 18 Environmental Consultants, Inc. http://grecn.kingcounty.gov/WLR/Waterrcs/StrcamsData/rcports/grcen- duwamish-loading-report.aspx King County. 2010a. DRAFT Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project. Prepared by Jeff Burkey, King County Department of Natural Resources and Parks. Prepared for Storrnwater Services Section, Capital Services Unit. King County. 2010b. King County G!S Center LIDAR, Topography, Geology, and Stream Location Layers, viewed with ARCGIS http://wwwS.kingcounty.gov/gisdataportaI/ King County. 2010c. Particle Size Evaluation of May Creek Water Channel Soils, Job Number IBI205, Task MTR. King County Department of Transportation, Materials Lab, Renton, WA. King County. 2010d. Sediment Muck Analysis of May Creek Water Channel Sample, email communication, King County Department of Transportation, Materials Lab, Renton, WA. King County. 2010e. May Creek Drainage Improvement Project 70% Design Progress Plans dated 10-22-10. King County. 2010f. Baseline Stream Conditions May Creek Drainage Improvements, CIP#9 A 1205. NCRS 1993. Soil Survey Division Staff. Soil survey manual. Soil Conservation Service. U.S. Department of Agriculture Handbook 18. http://soils.usda.gov/technical/manual/ Yount, J.C. and Glower, H.D., 1991 Bedrock Geologic Map of the Seattle 30' by 60' Quadrangle, Washington: U.S. Geological Survey, Open-File Report OF-91-147, scale 1: I 000000. I I 1. I I I' i ,I I I I I I ., I I I I I I I I I Doug Chin February 9,201 l Page l 7 References Anchor QEA, LLC. 2 l l 0. May Creek Erosion Stabilization Draft Report May Creek Sediment Transport Study Phase 3. Prepared for King County Department of Natural Resources. Booth, D.B., Haugerud, R.A., and Sacket, J. Geologic map of King County, Washington: scale 1: 100,000. Bretz, J. Harlen, 1913, Glaciation of Puget Sound Region, Bulletin 8, Washington Geological Survey, 244p. Burton, G. Allen, and Robert Pitt. 2002. Stormwater Effects Handbook: A Toolbox for Watershed Managers, Scientists, and Engineers. Lewis Publishers, Boca Raton, Florida. http://www. epa. gov/ cdnnrmrl/pu b 1 i cati ons/books/handbook/toc. pd f Foster Wheeler, 1995. See King County, 1995 below. GeoEngineers. 2008. May Creek Drainage and Restoration Plan, King County Washington. For King County Water and land Resources Division and Mid- Sound Fisheries Enhancement Group. Hart Crowser, 2009, Final Site Investigation Report, Loon Lake, Washington, prepared for the Washington Department of Natural Resources, 117 p. Access online September 2010 at: http://www.dnr.wa.gov/Publications/agr loon lake final invest report.pd[ Homer, Richard R., Joseph J. Skupien, Eric H. Livingston, and H. Earl Shaver. 1994. Fundamentals of Urban Runoff Management: Technical and Institutional Issues. Prepared by the Terrene Institute, Washington, DC, in cooperation with the U.S. Environmental Protection Agency. King County. 1995. May Creek Current and Future Conditions Report. Prepared by Foster Wheeler for King County Department of Natural Resources and Parks. Prepared for Stormwater Services Section, Capital Services Unit. King County. April 2001, May Creek Basin Action Plan. King County Department of Natural Resources, Water and Land Resources Division. King County 2007. Water Quality Statistical and Pollutant Loadings Analysis -Green- Duwamish Watershed Water Quality Assessment. Prepared by Herrera Doug Chin February 9, 2011 Page 18 Environmental Consultants, Inc. http:// green.kin gco un ty. gov /W L R/W aterrcs/S trea msData/ reports/ green- d uwa mish-I oad in g-report. a spx King County. 2010a. DRAFT Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project. Prepared by Jeff Burkey, King County Department of Natural Resources and Parks. Prepared for Stormwater Services Section, Capital Services Unit. King County. 2010b. King County GIS Center LIDAR, Topography, Geology, and Stream Location Layers, viewed with ARCGIS http://www5.kingcounty.gov/gisdataportal/ King County. 2010c. Particle Size Evaluation of May Creek Water Channel Soils, Job Number lB1205, Task MTR. King County Department of Transportation, Materials Lab, Renton, WA. King County. 2010d. Sediment Muck Analysis of May Creek Water Channel Sample, email communication, King County Department of Transportation, Materials Lab, Renton, WA. King County. 20 l Oe. May Creek Drainage Improvement Project 70% Design Progress Plans dated l 0-22-l 0. King County. 2010f. Baseline Stream Conditions May Creek Drainage Improvements, CIP#9Al205. NCRS 1993. Soil Survey Division Staff. Soil survey manual. Soil Conservation Service. US. Department of Agriculture Handbook 18. http:// soi Is. usda. gov /techn ica I/manual/ Yount, J.C. and Glower, H.D., 1991 Bedrock Geologic Map of the Seattle 30' by 60' Quadrangle, Washington: U.S. Geological Survey, Open-File Report OF-91-147, scale 1: 1000000. I I I I r • r • ' a II I) ,· i 0 r II ' I Ill • I loli'ilg Marsh Creek Restoration !Project Julia Turney, Geologist Doug Chin, Project Manager Wesley Kameda, Engineer Jeff Burkey, Hydrologist Erick Thompson, Stream Ecologist Lucy Traxinger, Engineer . o't f\enton Clt\l . Oivis1on p\ann1n9 ft.II 1 \l l\\\3 ®,~t/f.iVJ'f ~ I Table of Figures iii Figure I: Vicinity Map .............................................................................................................. 3 Figure 2: 1936 Aerial Photo Graph ........................................................................................... 8 Figure 3: Geologic Map .......................................................................................................... IO Ii) ' Figure 4: Reach Map .............................................................................................................. 11 Figure 5: Cumulative Sediment Distribution .......................................................................... 14 Cl\ Figure 6: HSPF Flow Frequency ............................................................................................ 15 Figure 7: Channel Wide Definitions ...................................................................................... 21 !3! GJ Ql D D 0 0 D I I I I I I I I I I I I I I I I I I I I 1.0 Purpose and Scope The Long Marsh Creek Restoration Project Basis of Design Report provides information on the design concepts, as well as detailed design criteria for the Long Marsh Creek Restoration Project(hereafter referred to as the Project). Project figures may be found in Appendix A. Detailed technical studies prepared to support the Project design development may be found in subsequent Appendices. 1.1 Project Location Long Marsh Creek (08.0289) is located east of Renton in unincorporated King County on a private property located on the south side of SE May Valley Road. (Figure I). Long Marsh Creek enters May Creek (08.0282) at River Mile 4.6 and is a perennial, 2nd order stream approximately I .65 miles long, that drains a watershed ofO. 78 square miles. Table I below lists the Long Marsh Basin characteristics (USGS, Stream Stats). Sediment control and stream restoration, including buffer enhancement, are proposed for this project site. Table I: Long Marsh Creek Basin Characteristics (Modified from USGS Stream Stats) !Parameter I Value I Drainage Basin, in square miles I 0.78 Mean Basin Elevation in feet I 862 ! Minimum Basin Elevation in feet i 351 j Maximum Basin Elevation in feet I 1220 Relief (maximum • minimum elevation), in feet I 869 I Mean basin slope in percent I 18.6 Percent of area with slope greater than 30 percent I 12.2 Percent of area with slope greater than 30 percent and facing North I 2.18 Area-weighted forest canopy, in percent, computed from NLCD 2001 canopy dataset I 86.1 ! Mean annual precipitation, in inches I 47. 1.2 Summary Description The Long Marsh Creek Restoration Project will create a meandering channel, remove invasive vegetation, control sediment delivery to May Creek and establish variable with stream buffer habitat. Plants such as red alder, western red cedar, Pacific willow and other early successional species will be densely planted to rapidly provide shade and cover loD1lg Marslh C1reelk, May Valley Long Marsh Creek Project Area oa Creek P~.k ' <Boo .. , ,~-------.,.... ..... ---'~~ i Lake\' '11¢,Pl ! R':a~" .. ·, }' · . · -,, Boren tr, ; g'!: .re 7~ Newcastle Open Space q,., ..... " ·-w,,., ,, s~ 89tl) May "' Creek Park S!861h5t ''c-Ore, . . 't~'SE .. , . s, ~ Coal ~ Creek Park Sidney AV11 N China ... ' -.6'11.J.s r~ Creek Open Space ,/ , . ' J'<ltftA~·-, ,' ~ .. .. N ....... t ,, Long Marsh Creek Project Location lf' • SJ,;,111'1 e Heights .I Park ,t SE 100th St_ NE 25th Pl ' May Creek Qpen Space w NE 24th St toney ek Opeo ;pace i ,NE 11th St ' NE 10th Pl ,,, z NE 1.lnd Pl f ... NE 22nd Sil NE 2111 Sc 1; NE.19tti1~ , .. IOthLn. NE 9th St , Klw1u'lls-~' P,irk • ! Renton< Renton! NE 7th St 1"' ~ ~ NE 6th Pl w w • ' • • I w z I • : l " = 1 NE 8th SI NE 6ih 5t 1 _NE 6th $t NE !Hh St r 10 5 o 10 20 30 40 Miles NE 25th St Ne 2'4th St NE 2ltd5t ¥,t. lltts,. w • ' May valley Parl< SE U2th SI se uJtn s, / S~ 120th St w z !!-, " ,, z HE 6th St w • t .E E w "' r • £ ~; j "?: NE 5th Pl I 1 ,~E '4th Ct 2 SE 116th St ~ r < ~ • • I, )/ SE 120th St I wlf ~ , "'I .,.., ,' f', Co4rt,e~ P11ri< 5 I l(I ~11 I' JI Figure 1 ~ King County I I I I I I I I ~ . I I filil ~ I I I I I I I I I I I I I I I I I I I throughout the site. After these plants have become established conifers and other species will be planted in a managed successional planting strategy. Woody debris and snags will be placed to provide structure, roughness and habitat substrates to the stream channel and upland buffer. Native and imported soil material will be used to create variable soil moisture and substrate conditions to support the stream environment. Habitat adjacent to the low flow channel will be created for invertebrates such as amphibians such as Pacific chorus frogs and Northwest salamander, fish species such cutthroat trout and coho salmon. 1.3 Goals The goal of the Project is to control sediment delivery to May Creek and provide beneficial stream habitat. The Project will restore in-stream fish habitat complexity and alluvial fan functions at the confluence of Long Marsh Creek and May Creek by enhancing approximately 280 linear feet of stream from an agricultural ditch to a more natural channel and creating about 50 linear feet of side channel along May Creek within the alluvial fan area. This will allow sediment to drop out in Long Marsh Creek prior to reaching May Creek, and will increase fish habitat complexity in Long Marsh Creek. 1.4 Objectives Specific objectives for the Long Marsh Creek site include: 1. Control'sediment transport by increasing stream sinuosity, creating natural depositional benches, creating a new side channel for May Creek with natural channel morphology to allow sediment deposition outside of the main channel. 2. Restore in-stream habitat complexity by adding woody debris and boulders to approximately 140 linear feet of stream channel. 3. Restore in-stream complexity to May Creek by creating a side channel for May Creek and allow discharge of high quality Long Marsh Creek gravels to the side channel, thereby enhancing May Creek habitat for salmon and cutthroat trout. 4. Restore and enhance approximately 0.18 acres ofriverine and upland riparian habitat by removing invasive vegetation, adding topography and planting native forested and scrub-shrub vegetation that will provide habitat for amphibians, and other aquatic species. 5. Create a minimum of 1600 square feet of off-channel permanent open water with two depth classes to provide seasonal rearing and refuge habitat for fish as well as habitat for wetland-associated birds, amphibians, aquatic invertebrates, and small mammals. 3 1.5 Summary of Technical Studies Technical studies and assessments were performed to verify the feasibility of the conceptual design and to provide design criteria for construction of the Project (Appendix B and C). These are briefly summarized as follows: • • The Long Marsh Creek Geomorphic Investigation (Turney, 2010) was performed to determine soil and groundwater characteristics. The results of this study included recommendations for soil materials to reduce infiltration and support the establishment of aquatic environments. Information from the report is included below. A summary hydrologic model (Burkey, 2010) of the project site was developed to analyze backwater conditions and develop channel and riffle geometries to convey design discharges and provide fish passage. Figures from the model are included below. 2.0 Project Site Conditions Long Marsh Creek is tributary to May Creek, located in the Puget Sound Lowlands of Western Washington. This broad rolling lowland is characterized by a mild maritime climate. It occupies a continental glacial trough and is composed of many islands, peninsulas, and bays in the Puget Sound area. Coniferous forest originally grew on the ecoregion's ground moraines, outwash plains, floodplains, and terraces. The distribution of forest species is affected by the rainshadow from the Olympic Mountains (Omernik, 1987). 2.1 Historical Conditions Historic 1872 survey map and aerial photo taken during flood events (see Appendix A) show that Long Marsh Creek, an unnamed drainage to the west and Indian Meadows Creek to east created a broad alluvial fan that pushed May Creek to the south side of May Valley. Historically the streams would have moved across the fan as sediment was deposited in the channel or debris flows brought large slugs of sediment from the slopes on the fan. In the late 1920s or early 1930s, May Creek was dredged to create a straight channel. May Creek and Long Marsh Creek appear in their current configuration in a King County 1937 aerial photo (Figure 2). A 42-inch culvert carries Long Marsh Creek under May Valley Road and in a second 48-inch culvert under fann structures and parking areas. At some point in the early 201 h century Long Marsh Creek was placed into an excavated agricultural drainage channel oriented north-south to join May Creek. A uniform low ( I foot) berm lies along the west side of the channel and statements from the previous property owners indicate the stream was regularly cleaned of sediments to provide conveyance capacity and permit tillage and pasturage in adjacent fields. 4 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ,, -1 I_ County Boundary Mountain Peaks Highways Legend Hlgll'MI)' 1936 BJW Aerial Photos X Arterial, lo<:111 Streets Lake& and Large Rivers (contJ Streams COMMENTS: Figure 2 The information Included on this map has been compiled by King County staff from a variety or sources and is subject to change without notice. King County makes no representations or warranl!es, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document Is not intended for use as a survey product. King County shall not be liable for any general, special, Indirect, lncldental, or consequential damages Including, but not limited to, lost revenues or lost profits resulting from the use or misuse of tho Information contained on this map. Any sale of this map or informaUon on this map is prohlbltod except by written permission of King County. Dato: 9/12/2011 Source: King County iMAP • Property Information (http://www.metrokc.gov/G!S/iMAP) 5 t.a King County 2.2 Land Use and Ownership May Valley supports pasture and low-intensity agriculture uses, small farms, and scattered single-family residences. Historically, May Valley was probably more fully utilized for agriculture production; however, under existing conditions the pastures in the project area are primarily horse pasture. The Long Marsh Creek project area is located on parcel 0223059091. The stream corridor is approximately 30 feet wide and bounded by horse pastures and fencing. 2.3 Watershed Geologic and Geomorphic Setting The Project site is located on the Long Marsh Creek alluvial fan in May Valley that formed at the base of Cougar Mountain. The wide and relatively flat May Valley (RM 3.9 to RM 7.0) was created by glacial ice melt runoff and is part of the "Kennydale Channel". The creek is underlain by recent alluvium over recessional outwash deposits and compacted glacial till. These deposits overlie Eocene Tukwila Fom1ation. The formation is composed of volcanic tuff, fine-grained volcanic sandstone and volcanic tuff-breccia. The Tukwila Formation outcrops in the hills above May Valley. The alluvial fan developed from the deposition of sediment in response to the loss of valley confinement and declining valley gradient. Sediment deposition on the fan raises the channel bed above the surrounding terrain and forces the channel to abandon the current alignment for lower ground. This process of sediment deposition and channel abandonment and formation can create a network of braided channels or a single channel incised into the fan. The geologic map is shown on Figure 3. The Long Marsh Creek, Indian Meadows Creek and unnamed drainage to the west of Long Marsh formed coalescing alluvial deposits. May Creek was dredged to form a linear channel between 1910 and 1936 (Foster Wheeler, 1995). The dredged channel may be located slightly north of the pre-dredged drainage. Long Marsh Creek is channelized and confined by a culvert under SE May Valley Road and a private culvert on the parcel. The channel gradient decreases from approximately 5% upstream of SE May Valley Road to approximately 3% below the private culvert. Long Marsh Creek appears as a straight channel following a fence line between fields in 193 7 aerial photographs. Long Marsh Creek drainage has been subdivided into four reaches (Figure 4), each reach exhibiting internally similar characteristics. Photographs of the sub-reaches arc located in Appendix B. Reach I extends from SE May Valley Road to the confluence with May Creek. Long Marsh Creek joins May Creek south of SE May Valley Road near 150th Place NE. The reach between the confluence and SE May Valley Road was in agricultural production prior to available 1937 aerial photography, and since that time has had a relatively straight channel aligned with a current property boundary. The channel is on the order of 2 feet 6 I I I I I I I I I [il (ti I I I I I I I I I I I I I I I I I I Long Marsh Creek, May Valley Geology Legend Qw-Wetland Deposits Organic Rich Sediment ~ King County I 82,CXl)()OO) 82,000164,00C246 ,00CB28 ,000 Feet ------ Qvr-Recessional Outwash Deposits Sand and Gravel Qvt-Vashon TIii Compacted Mix of Silt Sand and Gravel Tpt-Tukwila Formation-Mix of Volcanic and Sedimentary Material Long Marsh Creek, May Valley tQ King County' Reach Locations on 2009 Aerial I I I I I I I I I I I I I I I N I +. Not to Scale Firgure 4 I 8 I I I I I I I I I I I I I I I I I I I wide and several inches in depth at winter low flow. The stream banks are approximately I foot in height, and the surrounding floodplain/fan surface is primarily planted in pasture grass with some recent native plantings. Evidence was found of sand gravel deposition throughout this reach. Gravel in the channel is composed of Tukwila Formation representing the native Cougar Mountain bedrock source and granite and quartz material, reworked glacial material. The Tukwila sediments are generally angular to subangular and the reworked glacial is subrounded to rounded. At the confluence with May Creek the sediment is predominantly Tukwila sediments. Discussions with the property tenants indicate that sediment deposition extended into the adjacent pastures and required maintenance following a January 2009 storm event. A 100-foot section of culvert conveys the creek across a portion of the fan with open channel on either side. • Reach 2 of the creek crosses under SE May Valley Road in a culvert that marks the top of the present alluvial fan. In the area upstream or north of SE May Valley Road, the stream is more incised within a narrow floodplain. The stream follows a contact between glacial till and Tukwila Formation volcanic rock. The west bank of the stream appears to have been modified by the grading of what might have or narrow access road. The compacted surface now appears to have reverted to largely native vegetation, some of which is hydrophilic. The west bank in that area has been actively undermined and is presently a 3-5 foot high vertical bank with exposed roots in places. It appears that the channel has incised, possibly in response to the bedrock-glacial contact, narrow access road and/or the culvert elevation under SE May Valley Road. The stream is attempting to rebuild a connected floodplain by undermining its banks. Erosion has also been observed where the stream flows against the SE May Valley Road embankment before entering the road culvert. In the process, significant sediment is being delivered to the stream. These conditions only exist along approximately 150-200 feet of stream before the gradient increases (approximately 400 feet upstream of SE May Valley Road) and the channel begins to climb Cougar Mountain. • Reach 3 includes the steepening gradient of the channel above Reach 2. The steepening gradient is a result of exposed Tukwila Formation, fonning bedrock cascades. Very little sediment is present within this reach; however, intennittent collections of woody debris do trap modest amounts of sediment. Given the steep gradient and the relatively smooth channel, the wood accumulations appear to be readily breached during higher flow events. Given the small size of the debris accumulations, they likely contribute to the background rate of sediment transport, but do not likely result in large episodic sediment loads. • Reach 4 starts approximately 900 feet upstream of SE May Valley Road where the stream gradient flattens and a small man-made impoundment was found. More sediment is apparent in this reach, and it is possible that a failure of an impoundment like the one observed could release a significant amount of sediment into the system. However, there is no direct evidence of any recent failures. The reconnaissance was stopped approximately I 000 feet upstream from SE May Valley Road because the remaining 9 portion of the drainage is forested with no development and therefore, is unlikely to have significant, correctible sedimentation problems. Active erosion in Reach 2 above SE May Valley Road is the apparent source for much of the sediment reaching May Creek. Sediment movement behavior in Reach 1 was observed during December 20 I 0. During high flows in May Creek, Long Marsh Creek deposited sand, gravel and small cobbles at the high water boundary in May Creek. Water backing up in the Long Marsh Channel deposited sand as overbank deposits above the flood confluence with May Creek. As the water elevations in May Creek dropped, Long Marsh carried gravel farther down toward May Creek. Flows in Long Marsh Creek subsequently scoured the recent channel deposits and transport sediment to the main May Creek channel. This indicates that lower flow events on Long Marsh Creek may deliver more sediment directly to the May Creek channel while larger storm events that produce higher flow events in May Creek deposit more sediment higher on the alluvial fan. Two pebble counts (Wolman, 1954) of stream substrate were conducted January 7, 2011 on Long Marsh Creek substrate above the confluence with May Creek. One count, Transect I, was conducted approximately 50 feet downstream of the private culvert and the second 45 feet upstream from the confluence with May Creek. Pebble measurements for the two transects are shown below in Table 2. Figure 5 shows the cumulative particle size distribution of the sediments. Analysis of the two transect counts (BAGS, 2008) indicates that for sediments Table 2 · Pebble Count Data for Two Transects Long Marsh Creek Cumulative Distribution Size finer than Transect Transect tmml 1 2 2 14.0 4.0 2.8 16.0 5.0 4 18.0 5.0 5.6 20.0 7.0 8 24.0 11.0 11.3 27.0 15.0 16 33.0 18.0 22.6 37.0 34.0 32 53.0 50.0 45.3 68.0 71.0 64 75.0 82.0 90.5 92.0 97.0 128 98.0 99.0 181 100.0 100.0 IO I I I I 11 I I I I I I (ii Ill I I I I I I I I I I I I I I I I I I I I I 100.0 90.0 80.0 -- C 70.0 ·-- ~ 5 60.0 -~ C 50.0 "' c 40.0 ~ u ---~ 30.0 0. 20.0 10.0 0.0 Cumulative Particle Size Distribution I I I -------/-----T I I I ----- -1-:,_ -~ ...-r1: , , . , , • 1 r ··, ·Hi I 10 I l{1r ! I. . --_, ~- ! ' l~. --. -- ) -- I ----- ------ I I I I I I 100 Millimeters I I I I -------- ----.. ,_ I I -----~l- i- I I I I I I I 1000 I-Transect 1 •••• Transect 2 [ I ---- ----- I I I I ---ti 11 I 11 I 10000 Figure 5: Cumulative Size Distribution of Sediments Along two Transects in Long Marsh Creek (BAGS, 2008). less than 20 mm there is a statistically significant difference in sediment size between the two transects. The difference in sediment size distribution likely represents post high May Creek flood scour exposing earlier sediment deposited during different flow regimes in the second transect. 2.4 Hydrology and Hydraulics Stream flows are seasonal, with peak flows occurring October-February, and low summer base flows occurring between July and September. Modeling estimates peak flows (I 00 years) of approximately 90 cubic feet per second (cfs) and one year flow of approximately 10 cfs (Burkey, 2011 ). 11 10' 10' § 0 HSPF Sim. Long Marsh Existing wy1949-2008 Weighted Skew (G= 0.056254) Probability Plot 87.0-dl 66 52.8 " 28 9-d § § § § 0 0 0 0 Exceedance Probability M~L~rn l?B ~•r,,,cttl (y,oat) 1cr.1 kloJ :oo,oo ~~.19 10:i.,o 100.00 ~l.Ol ·,~.11 )0,00 ,,.~~ J~.7B 40,00 i.:.~~ 11., .. , 2~.00 l.5.H Ol,2~ 10.00 r<.n ~3.4~ 10.00 r.2.H ~J.)I ~.00 ~2.~J O.:'l ?.00 :8.H :8.44 1.~o n.11 2i.~1 l.t~ l~.l(, U.H l ,01 !0.0J s. H -119 --95%CI ---* w,~11 D 2008 0 2007 0 ,... 0 2008 0 "" ~ 1991 Figure 6: l-lSPF Simulation of Flow Frequencies on Long Marsh Creek (Burkey, 2010) In May Creek fines with a diameter of I mm or greater require shear stresses above what the mean annual flow rate can produce. Shear stresses in May Creek are far below forces necessary to mobilize gravels that are being deposited by Long Marsh creek (Burkey, 20 I 0) 2.5 Water Quality Long Marsh Creek is not on the Washington State Department of Ecology's 303(d) list of impaired waters. May Creek is on the 303(d) list for Fecal Coliform downstream of the project area near Lake Washington. The reach of May Creek in the project area is not on the 303(d) list. 2.6 Stream Habitat The in-stream habitat within the reach of Long Marsh Creek below SE May Valley Road (Reach I) is somewhat shallow low-gradient riffle with little to no pools. The exception includes a small plunge pool beneath a pipe that carries Long Marsh Creek through a section of pasture and farm equipment parking. This pipe is likely a partial barrier to upstream fish migration during some flows because of water velocities. The stream is maintained in a relatively straight alignment by property owners from the pipe to the stream's confluence with May Creek. There is a narrow riparian area adjacent the stream that has been planted in 12 I I I li {I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I the last ten years or so. The culvert at this location is also likely a partial fish barrier during certain flood events. Stream habitat immediately upstream of SE May Valley Road (Reach 2) consists oflow gradient riffle and small pools. There is a narrow riparian environment that is providing some cover and complexity to this section of stream. Juvenile salmonids were observed in some of the small pools and edgewater habitats located within this section of the stream. This indicates that fish are able to pass both the culvert above the project area and the culvert under SE May Valley Road. The ravine is well forested and instream habitat is almost exclusively high gradient riffle (cascade), though there were numerous small pools on the edges of the channel, usually formed by aggregations of small sticks and leaf litter that would not persist through storm flows. Upstream of the steep bedrock cascades the instream habitat is similar to the stream section below the cascades, with possibly more pools habitats. The riparian area is wider and has a much more diverse coniferous forest. 13 3.0 Project Design The Long Marsh Creek Restoration Project is designed to with the goal of reducing sediment movement to May Creek and enhancing approximately 280 feet of the lowest reach of the Creek by creating meanders, adding habitat features, and planting native vegetation. The meanders, terrace features and vegetation will also enhance sediment-trapping capabilities to reduce transport of sediment to May Creek. The enhancement also includes creation of an approximately 50-foot-long side channel parallel to May Creek that will join with Long Marsh Creek prior to discharging to May Creek. The side channel will provide an area of gravel substrate. Temporary and permanent easements will be acquired from property owners to protect the mitigation site in perpetuity within a permanent stream corridor. Estimates of sediment delivery to the Project are based on sediment deposition by Long Marsh in May Creek subsequent to a 2002 sediment excavation project in May Creek. This range of sediment production and delivery is representative of the variable and episodic nature of sediment production and transport. Larger cobbles are expected to settle out upstream of the SE May Valley Road culvert, with small cobble to silt sized material settling out in May Creek. L WD will be placed in the channel every 8 feet (4 channel widths) to create a moderately entrenched, moderate gradient, step-pool channel morphology with a sinuosity of> 1.2. Plant species will include trees, shrubs, groundcover and emergents. Species utilizing the stream reach will include aquatic invertebrates, amphibians, and migrating salmonids. Design plans are shown in Appendix C. 14 I [I I I I I I 11 I II I I I I • I I I I I I I I I I I I I I I I I I I I I I 4.0 Design Criteria Specific design criteria are provided as derived from analog, empirical or analytical methods. Analog design criteria are derived from reference wetlands, and use structural wetland characteristics as a template for design. Empirical design criteria use mathematical relationships derived from observed relationships, e.g. relating bankfull discharge to channel width or depth. Analytical design criteria use process-based approach to design; e.g. density- dependency relationships obtained from research design studies. 4.1 Buffers Definition The types and aerial coverage of land uses within 165 feet of the creek. Rational Land use adjacent to Long Marsh Creek has historically been in agricultural and pasture. There are existing fences and pastures on either side of the creek providing a 25 to 30 foot wide corridor. The area for stream work and buffer restoration is limited due to fencing and existing property. Methods King County Code Title 16 and 22. Design Criteria The Long Marsh Creek channel will be graded and planted. The channel area will be widened up to five feet near the confluence with the new May Creek side channel to provide more area for the channel meanders. The new May Creek side channel will be bounded on the south by May Creek. No new buffer area is available for the creek alignment. 4.2 Channel Cross Section Definition A transect in the vertical plane oriented across the channel Rationale Channel shape is critical to water discharge and sediment retention and conveyance. The May Creek side channel provides sediment storage and side channel refuge for small fish. Methods Hydraulic modeling by Burkey (20 I 0) and Kamada (2011) and channel design experience (Thompson, 2011). Design Criteria Channel cross sections were developed based on design discharges, planform geometry, and subreach slope. The Long Marsh channel was sized to convey the I year storm in a low flow 15 channel and provide sediment deposition behind large woody debris on benches within the channel. The cross sectional area has been adapted to the curvature of the meanders. Table 3: Long Marsh Creek Channel Depth Recurrence Interval Flood flow Channel Depth 1.01 Year 9.8 cfs I.I ft depth 2 Year 28.9 cfs 1.5 ft deoth The May Creek side channel cross section was sized to allow flow at a 2-year event. L WD will be positioned in the channel to provide complexity, clean gravel substrate will be placed in the channel and the side slopes designed to provide an "island" between the main May Creek channel. 4.3 Channel Pattern Definition The configuration of the east reach of the Project described in terms of relative curvatures. Channel patterns are related to length, slope, sinuosity, and sediment load. Rational Channel pattern is a primary geomorphic parameter that changes in response to hydrology, sediment supply, and channel slope. The area available to design the Long Marsh channel is constrained by pastures. The sinuosity and meander amplitude were chosen to maintain a low flow channel, enhance sediment deposition and remain within the available property boundaries. Methods On December 12, 20 IO a 60-year recurrence interval event occurred in the May Creek Basin. The location of flooding on Long Marsh Creek below SE May Valley Road was surveyed. The observation showed that the below SE May Valley Road Long Marsh increased its sinuosity slightly during the event and the channel below the private culvert is relatively stable. Sinuosity, meander wavelength, amplitude and radius of curvature were maximized within the available space. Values were checked to be within US Forest Service Alluvial Fan Process Group characteristics for micro to moderate alluvial fan. These values include: Long Marsh Creek Design Criteria o Valley Length= 280 If • Stream Length = 325 If o Sinuosity= 1.16 • Meander Amplitude= 10-12ft • Radius of Curvature= 12ft • Meander Wavelength= 50-70ft The May Creek side channel is designed to allow deposition of Long Marsh Creek sedimenls, to not disrupt the flow velocities in the main May Creek channel and therefore 16 I I I I I I I I I I I I I I a I I I I I I I I I I I I I I I I I I I I I reduce the capacity of May Creek to carry fine sediment, and to provide side channel habitat with gravel substrate. The pattern is a gentle arc that represents a high flow meander channel. May Creek Design Criteria • Side Channel Length= 80 If • Meander Amplitude= 20 ft • Radius of Curvature= IO ft • Meander Wavelength =NIA 4.4 Design Discharge Definition The discharges (flows) that have the greatest impact on channel boundaries and wetland hydrology. The design discharge is used to design certain habitat elements, ensure fish passage of grade control structures, and evaluate flow depths in channels. Bankfull width describes the flow event that just fills and equilibrium alluvial channel, specifically to the depth where the flow width to depth ration is a minimum. Rationale Because the Project requires a full channel reconstruction a suite of design discharges are likely necessary to develop channel forms, cross-sections, and profiles that meet all project objectives. The channel design must provide hydrology to support sediment deposition, provide fish passage, transport future sediment loads and meet site constraints. Flows should establish two water depths regimes in Long Marsh Creek. Low flows in an inner channel should equal or exceed 3 inches and the low flow channel bankfull flow (I-year event) in winter will be 18 inches. Flows above the one year storm will spread out on a broad outer channel. The outer channel will contain the 100-year flood event. The water depths will provide sediment deposition areas, habitat for different plant communities, which in turn, provide broader range of habitats for faunal communities. Sediment deposition will slow the delivery of sediment to May Creek. Minimum water depths in the low flow channel will maintain fish passage during summer months. In Western Washington there is a general correlation between the bankfull discharge and the l.25-year recurrence interval flow, when flow within the channel just begins to spill over into the active floodplain (Castro and Jackson 2001). 17 Bankfull Discharge Figure 7: Channel width definitions. Methods HEC, 2008 Design Criteria 1.25-year recurrence interval= 19 cfs 4.4.1 Effective discharge flow: Definition The single discharge event that transports the larges volume of sediment over time. Rationale To evaluate the relationship between channel geometry and sediment transport capacity and the implications of channel forming discharges. Methods HEC, 2008 Design Criteria 1.01-year recurrence event= 9 cfs 4.5 Planting Plan and Density Definition Species type, size, number and density of planted species. Rationale King County Code 21 A .21 requires critical areas restoration and enhancement. Guidelines published by ODES provide plant numbers based on fonnulas. 18 I I I I I I I I I I I I I I I • I fl I I I I I I I I I I I I I I I I I I I Methods DDES Critical Areas Restoration and Enhancement in King County spacing formula was considered and modified by the stream side location and amount of wood that will be placed in the stream. The King County native plant guide provides lists of plants and preferred growing conditions. Design Criteria: The alluvial fan area is relatively wet environment due to shallow groundwater and flooding from May Creek. Selected species need to be able to withstand periodic flooding on the high flow bench and seasonally shallow groundwater. The south facing aspect will be in sun to part sun until tree and shrub species become established. Long Marsh Creek is located between two active pastures and total view blockage is not desirable to the property manager. Proposed plant species are listed in table 3 below~ Table 3: Planting Schedule Scientific Name Common Name Quantity Size Conditions Plant Spacing Long Marsh Creek Thuja plicata Western Red Container min 18" High flow channel, Cedar 10 ht, full, dense slope edge locate in foliage, cluster of willows svmmctrical crown Bctula papyrifcra Paper Birch 8&8 5-6' ht, full, High flow channel 9 dense foliage, within 50 feet of symmetrical crown May Creek Fraxinus latifolia Oregon Ash B&B 5-6' ht, full, High flow channel, 10 dense foliage, base of slope symmetrical crown Comus scricca Red Osier Container 18" -21" Clusters of three on Dogwood 27 ht and spread, min high flow channel two stems Acer circiantum Vine Maple Container 18" -21" Clusters of three on JO ht and spread, min high flow channel two stems Salix iasiandra Pacific Willow Live stake, min 36" 3 'oc staggered. long at Yi'' to 3/. " Stakes driven into 55 diameter, min 12 high flow channel lateral buds per distributed along stake creek Salix sitchensis Sitka Willow Live stake, min 36" 3 'oe staggered long at VJ" to%" Stakes driven into 55 diameter, min 12 high flow channel lateral buds per distributed along stake creek Rubus spcctabalis Salmonbcrry Container 18" -21" Clusters of three on JO ht and 15" spread, high flow channel dense, multiple stems 19 I Symphoricarpos Snowbcrry Container 15"-18" Clusters of three on albus 30 ht spread, full upper bank of high flow channel I Rosa nutkana Nootka Rose Container 15"-18" Clusters of three on 30 ht spread, full upper bank of high flow chaMel I Polystichum Western Sword I Gallon container Distributed munitum Fem 40 min 3 fronds Achillca Yarrow IO cubic inch Plugs Distributed millcfolium 40 or 4" pot I Aruncus dioicus Goat's Beard IO cubic inch Plugs Distributed 40 or4"pot Tcllima Fringccup 10 cubic inch Plugs Distributed grandiflora 40 or4" pot I Carcx lcnticularis Shore Sedge IO cubic inch plugs Clusters adjacent to 30 low now channel Scripus Small-fruited IO cubic inch plugs Clusters adjacent to microcarpus Bulrush 30 low flow channel I Oxalis oregano Wood-sorrel 50 4 "pot Distributed May Creek Side Channel I Thuja plicata Western Red Container min 18" "Island" between Cedar 3 ht, full, dense main and side foliage, channel svmmetrical crown Comus scricea Red Osier I gal Container "Island" between I Dogwood 3 min two stems main and side channel Symphoriearpos Snowberry I gal Container min "Island" between I albus 6 two stems main and side channel Carex lenticularis Shore Sedge IO cubic inch plugs Low bank along 6 island between main and side I channel Scripus Small-fruited IO cubic inch plugs Low bank along microcarpus Bulrush 6 island between main and side I channel Salix iasiandra Pacific Willow Live stake, min 36" 3 'oc staggered. long at W' to%" Stakes driven into I diameter, min 12 bunks distributed 20 lateral buds per along island stake between May Creek main and I side channel I I I I I 20 I I I I I I I I I I I I I I I I I I I I Salix sitchcnsis Sitka Willow 4.6 lnstream Wood Debris Definition 20 Live stake, min 36" 3 'oc staggered long at Y2" to % " Stakes driven into diameter, min 12 banks distributed lateral buds per along creek stake Wood debris are all pieces greater than I 0cm in midpoint diameter and 2m in length. Key pieces are defined as a log and/or root wad that is independently stable in the stream bankfull width (not functionally held by another factor, i.e. pinned by another log, buried, trapped against a rock or bed form) and retaining, or having the potential to retain, other pieces of organic debris. Rationale Wood debris (WD) plays an important role in controlling channel morphology, the storage and routing of sediment and organic matter, and the creation offish habitat (Fox and Bolton, 2007). Methods: Fox and Bolton, 2007 Design Criteria The number and volume of in-stream wood pieces. In-stream was specified (Table 4: In- stream Wood Debris) with total quantities of WO based on I WO pcs p/ 11.3 ft stream based on median values for Western Washington State. Key pieces= I Key pcs p/ 55ft based on median for Western Washington State. Additional pieces arc being added to provide sediment stornge and channel complexity. Table 4: In-stream Wood Debris Long Marsh and May Creek LonQ Marsh channel Mav Creek side channel 4. 7 Sediment Transport Definition Channel lengths 280 ft 50 ft TOTAL Key (Large) LWD TOTAL LWD LWD pieces (Med& Pieces Small) pieces 9 15calculated\ 25 34 3 (1 calculated\ 5 8 12 30 42 Sediment yield is the total sediment load that leaves a drainage basin. Coarse sediment is transported by streams as bed load and fine sediment is transported as suspended load. 21 Rationale Sediment deposition on benches above the Long Marsh Creek low flow channel and in May Creek side channel will reduce sediment deposition in May Creek and the associated loss of flood storage capacity. Methods: The estimate of sediment yield is based on estimates of sediment volume deposited between 2002 and 2010 taken from survey elevation data collected by KCDNRP. Design Criteria Sediment yield in the Long Marsh Creek drainage was estimated from the accumulation of sediment in May Creek from Long Marsh Creek between 2002 and 20 I 0. Approximately 6.56 cubic yards (5.02 cubic meters) or 9.05 Tons (1.38 tons per cubic yard) of sediment have accumulated at the confluence of Long Marsh and May Creek as determined from survey data after the sediment removal project in 2002 and again in 20 IO (Kameda, 20 I I). This equals approximately .82 cubic yards or .63 cubic meters per year. The material at the confluence represents both bedload and suspended load carried by Long Marsh Creek that May Creek is unable to remove. This volume underestimates the total sediment yield as May Creek may carry very fine ( clay size) suspended sediments during higher flow events. The fine sediment is carried by May Creek and partly drops out of suspension as flows slow in May Creek. During flooding additional sediment deposition is occurring downstream of the foot bridge where Long Marsh and May Creek flows eddy against the bank. The source sediment for this downstream deposition appears to represent both Long Marsh and May Valley sediment. As noted in the discussion of existing conditions, Long Marsh Creek Reach 3 and 4, the forested slopes of the Long Marsh Creek drainage, are stable and the channel is underlain by Tukwila Formation bedrock. There are a number of log jams observed in the drainage that retain large quantities of sediment. Modeling of sediment loads from the forested slopes is difficult since the channel is not an alluvial channel. Sediment yield to the channel comes from forested slopes by soil creep, tree throw, surface erosion of the forest floor, and surface erosion associated with slope failures. Sediment yield from forested slopes to streams has been reported (Hassan, 2005) from various investigations at rates ranging from lm3/km/yr of channel bank to 1 Om 3 /km/yr drainage area for soil creep to surface erosions. The Long Marsh Creek cumulative stream length is 4.26 km (this measurement includes all of the side channels) and the basin is 2.02 km 2 (USGS Stream Stats, 2011 ). Dividing the annual yield of .63 cubic meters per year by the stream length provides an estimate of0.15 m3/km/yr. The calculated rate based on area is 0.31 m 3/km2/yr. These two estimates are lower than the published sediment yield rates for forested drainages. Reach 2, the area above SE May Valley Road is undergoing active erosion. The drainage area of Reach 2 is approximately 2.8 acres or .0 I km 2, a relatively small part of the Long Marsh Creek drainage basin. This reach has several houses/buildings and roads and is most highly developed portion of the basin. Published (Hassan, 2005) sediment yield rates for road areas can be 1000 m 3/km2 /yr. The drainage area of Reach 2 is approximately .Olkm2 • Long 22 I I I I (I I I I I I I I I I I I I I I I I I I I Marsh Creek sediment yields from Reach 2 do not generate the I Om3 /km2 that this rate suggests. However, due to the visible erosion in Reach 2, this area may be the source of a higher percentage of the basin sediment yield. The estimated yields based on the survey results are lower than published rates for similar streams. The lower stored volumes may represent courser sediments and the finer sediments are being moved downstream to the grass lined channels farther downstream. Greater volumes of sediment may be trapped in the upper reaches of the drainage behind log jams within the channel and delivery rates are lower than anticipated. Sediment storage in the redesigned Reach I will be located on eight outside meander bends set with key LWD above the low flow channel. These benches will be used to catch and deposit sediment. Sketches of the configuration and an example photograph from Olsen Creek are attached. • Using the bench size of25 to 30 feet long and 10 to 15 feet wide provides a maximum area of 20 feet by IO feet by 0.8 feet equal to l 60ft3 or 4.53m3 for sediment storage on each bench. • Eight benches provide a maximum of 36m3 of sediment storage in the Long Marsh channel. • The May Creek side channel provides a maximum of 5 feet by 40 feet (the down stream end of the channel) by 2 feet of depth equal to a maximum of 400ft3 or 11 m3 of sediment storage. • The combined sediment storage potential for the Long Marsh project is 47m3 • This provides an estimated 74 years of sediment storage at the estimated sediment yield rate of the last eight years. Events such as log jam failure in the upper reaches of Long Marsh Creek may shorten the storage "life" of the project. Low precipitation and runoff may lengthen the sediment storage time frame. 4.8 Soils Definition The loose top layer of the Earth's surface, consisting of rock and mineral particles mixed with decayed organic matter (humus), and capable of retaining water, providing nutrients for plants, and supporting a wide range of biotic communities (American Heritage 2008) Rational The area around Long Marsh Creek is an alluvial fan and history of agricultural use. Disturbing the existing soil to excavate the new channel will remove topsoil needed for plant establishment. Methods Top soil will be salvaged during excavation and reused on the slopes and benches. Topsoil wi 11 be imported for use Top soil will be tilled into the planting areas to minimize the loss of fines and organic material by runoff during plant establishment. Design Criteria Native soils are mapped as Alderwood gravelly sandy loam, 6 to 15 percent (AGc) on the slopes above May Valley and Bellingham Silt Loam in the valley. The Alderwood series is made up of moderately well drained soils that have a weakly consolidated to strongly consolidated substratum at a depth of 24 to 40 inches. These soils are on uplands. They formed under conifers, in glacial deposits. Slopes are O to 70 percent. The Bellingham series is made up of poorly drained soils that formed in alluvium, under grass and sedges. These soils are nearly level and are mostly in depressions on the upland glacial till plain. In general soil will meet the following specification: Gravel<2.9 inches, Sand 0.19-0.003 inches, Silt .003-.0002 inches Clay <.0002 and approximately 40-50% organic material. 4.9 Substrate Definition Loose sand and gravel laid down as a subaqueous deposit by stream transport (Pettijohn, 1975 ). Rational Long Marsh Creek created an alluvial fan composed of materials eroded from the Tukwila Formation and surficial glacial deposits overlying the Tukwila Formation. The new channel excavation is expected to be formed from the same materials that underlay the existing channel. Excavated deposits will be retained and reused to shape the meander benches, Design Criteria Pebble counts conducted prior to excavation will be used as the basis for the channel gravel design. I I I I I I I I I a I I I I I 11 I I I I I I I I I I I I I I I I I I I I I 5.0 Literature Cited The American Heritage Science Dictionary. 2008. Published by Houghton Miffiin Company. All rights reserved., © 2002 by Houghton Miffiin Company. Azous, A.L, Bowles, M.B., Richter, K.O. 1998. Reference standards and project performance standards for the establishment of depressional flow-through wetlands in the Puget Lowlands of Western Washington. King County Department of Development and Environmental Services, Renton, WA. Bags I-See Wilcox Booth, D. B., 1990, Stream-channel incision following drainage-basin urbanization: Water Resources Bulletin, v. 26, p. 407-417. Booth, D. B., 1991, Urbanization and the Natural Drainage System--Impacts, Solutions, and Prognoses: Northwest Environmental Journal, v. 7, p. 93-118. Booth, D.B. and Henshaw P., 2000, Rates of Erosion in Small Urban Streams, in M. Wigmosta ed., Stream Channels in Disturbed Environments: AGU Monograph Series. Booth, D. B., D. Hartley, and C. R. Jackson, 2002, Forest cover, impervious-surface area, and the mitigation of storrnwater impacts: Journal of the American Water Resources Association, v. 38, p. 835-845. Burkey, Jeff, 2010, Hydrologic model of Long Marsh Creek, email communication, January 25,2011. Castro, J.M. and P.L. Jackson. 2001. Bankfull discharge recurrence intervals and regional hydraulic geometry relationships: Patterns in the Pacific Northwest, USA. Journal of the American Water Resources Association 3 7(5): 1249-1262. Celedonia, Mark T. 2002. Establishing appropriate benchmarks for site development by documenting success ional characteristics. WSDOT, Olympia, WA. Cooke, S. S. and Azous, A. 1993. Effects of urban stormwater runoff and urbanization on palustrine wetland vegetation. Puget Sound Wetlands and Stonnwater Management Research Program. University of Washington, Seattle, WA. Fox, Martin and S. Bolton. 2007. A regional and geomorphic reference for quantities and volumes ofinstream wood in unmanaged forested basins of Washington State. North American Journal of Fisheries Management 27:342-359, 2007. American Fisheries Society. Geo Engineers. 2008. May Creek Drainage and Restoration Plan, King County Washington. For King County Water and land Resources Division and Mid-Sound Fisheries Enhancement Group. 25 Kim, D. K., Ewing, K., Giblin, D.E. 2006,Controlling phalaris arundinacea (reed canarygrass) with live stakes: a density-dependent response. Ecological Engineering article in press. King County. 1995. May Creek Current and Future Conditions Report. Prepared by Foster Wheeler for King County Department of Natural Resources and Parks. Prepared for Stormwater Services Section, Capital Services Unit. Omernik, J.M. 1987. Ecoregions of the conterminous United States. Map (scale 1:7,500,000). Annals of the Association of American Geographers 77(1):118-125. Pacific Northwest Center for Geologic Mapping Studies, 2006, Geologic map of King County, Washington: D.B. Booth and A. P. Wisher, compilers, scale I: I 00,000 (available at http://geomapnw.ess.washington.edu/services/publications/map/data/KingCo _ composite. pdf) Traxinger, Land Kameda, W, Estimates of Sediment Deposition from Long Marsh Creek 2002 to 2010, personal communication, July 2011. U.S. Department of Agriculture. Urban hydrology for small watersheds. Technical Release 55 (TR-55). National Technical Information Service. 1986. U.S Forest Service. October 2010, Alluvial Fan Process Group, Channel Type User Guide down loaded from http://dspacc.nitle.org/bi tstream/handle/ I 0090/20008/Channel-Type-U ser- Guide-Revision.pd f?seguence= 16 April 8, 2011. US Geological Survey, StreamStats, Washington, Streamflow Statistics and Basin Characteristics for Long Marsh Creek, down loaded from http://water.usgs.gov/osw/streamstats/Washington.html , accessed between February 2011 and August 20 I I. WDF (Washington State Department of Fisheries). 1975. Catalogue of Washington Streams and Salmon Utilization, Lake Washington-Sanunamish Basin. Olympia, Washington. Washington State Department of Fish and Wildlife, 2003. Design of road culverts for fish· passage. http://wdfw.wa.gov/hab/engineer/cm/. Wilcock, P., Pitlick, J., and Cui, Y., 2006, Sediment Transport Primer and BAGS User's Manual, Part I, Gen. Tech. Rep. RMRS-GTR. Fort Collins, CO USDA, Forest Service, Rocky Mountain Research Station. Downloaded from: h ttps://j share. johnshopk ins.edu/pwi lcoc I /public html/Skamania%20Short%20Course.htm 26 I I I I I I I I I I I I D I I I I I I I t) May Creek Flooding Ci rca 1972 fro m King County Department of Natura l Re sources May Creek Proj ect Files I I I I I • I I I I I I I I I I I I I I I I I I I Reach I loo king so uth from May Valley Rd. Reach I lookin g no rth fr o m the confluen ce with May Creek. Reach 3 Looking up -s tream Reac h 4 s howi ng bedroc k cascade Ph otographs by Eri ck Thompson and Jul ia T umey, Kin g County Road Services Di vis ion . I I I I I •• I I I I I I I I :I I ,, I I ". ,.._ -···-- " \. l •• M •.>.' • ......... ._, -,.,, .. -.,-,?- ,.., " )' . I -,,,. ,. ·---f ' . ' .. THE EXISTING TOPOGRAPHIC AND PHYSICAL FEATURES SHOWN ON THIS PLAN ARE BASED ON A COMBINATION OF FIELD OBSERVATIONS AND LAND SURVEY USING ASSUMED BASIS OF COORDINATES PURPOSE: MITIGATION FOR MAY CREEK DRAINAGE IMPROVEMENT AND CONTROL SEDIMENT DELIVERY TO MAY CREEK DIRECTIONS TO SITE: SOUTH ON SE MAY ALLEY RD. GO APPROX. 300 FT PAST 150TH L SE, TO LONG MARSH CREEK CROSSING AT 5019 SE MAY VALLEY RD. OR TRAVELING ORTH, APPROX. 300 FT BEFORE 150TH PL S DATUM: HORIZ.: NAD 83 VERT.: NAVD88 PROJECT TITLE: LONG MARSH CREEK RESTORATION SHEET TITLE: VICINITY MAP SCALE: ASSISTANCE BY: D.C., WES K., J. T. DRAWN BY: L. TRAXINGER ROPOSED WORK: ' ~/ I ·' ' . l , . ·' .. ~ ,,,. ~ King County CREA TE A MEANDERING CHANNEL AND AN ADDITIONAL SIDE CHANNEL, REMOVE INVASIVE VEGETATION AND PLANT NATIVE VEGETATION SHEET: 1 of 11 DATE: JULY 18, 2011 I ( r. SHEET 1 2 3 4 5 INDEX DESCRIPTION VICINITY MAP SHEET INDEX SITE PLAN DESIGN PLAN SECTIONS 6 7 LOG AND BOULDER DETAIL AND SECTION TESC PLAN 8 TESC DETAILS 9 10 1 1 PLANTING PLAN AND NOTES PLANTING DETAILS PLANTING SCHEDULE THE EXISTING TOPOGRAPHIC AND PHYSICAL FEATURES SHOWN ON THIS PLAN ARE BASED ON A COMBINATION OF FIELD OBSERVATIONS AND LAND SURVEY USING ASSUMED BASIS OF COORDINATIES PURPOSE: MITIGATION FOR MAY CREEK DRAINAGE IMPROVEMENT AND CONTROL SEDIMENT DELIVERY TO MAY CREEK k:iRECTIONS TO SITIE: SOUTIH ON SE MAY f.lALLEY RD, GO APPROX. 300 FT PAST 1 SOTIH bL SE, TO LONG MARSH CREEK CROSSING AT h5019 SE MAY VALLEY RD. OR TRAVELING NORTH, APPROX. 300 FT BEFORE 150TH PL SI PROJECT TITLE: LONG MARSH CREEK RESTORATION SHEET TITLE: SHEET INDEX DA TUM: SCALE: NO SCALE HORIZ.: NAD 83 ASSISTANCE BY: D.C., WES K., J. T. VERT.: NA VD88 DRAWN BY: L. TRAXINGER ~ King County PROPOSED WORK: CREA TIE A MEANDERING CHANNEL AND AN ADDITIONAL SIDE CHANNEL, REMOVE INVASIVE VEGETATION AND PLANT NATIVE VEGETATION SHEET: 2 OF 11 DATIE: JULY 18, 2011 I I I • I (I. I i li I It I I I I I I. ff I I •• I I ,1 ;I I I I I I I I I I I I I : I I PURPOSE: MITIGATION FOR MAY CREEK DRAINAGE IMPROVEMENT AND CONTIROL SEDIMENT DELIVERY TO MAY CREEK DIRECTIONS TO SITE: SOUTH ON SE MAY ALLEY RD, GO APPROX. 300 FT PAST 150TIH L SE, TO LONG MARSH CREEK CROSSING AT 5019 SE MAY VALLEY RD. OR TRAVELING ORTH, APPROX. 300 FT BEFORE 150TH PL S DATUM: HORIZ.: NAO 83 VERT.: NAVD88 PROJECT TITLE: LONG MARSH CREEK RESTORATION SHEET TITLE: SITE PLAN SCALE: 1 "=60' ASSISTANCE BY: D.C., WES K., J. T. DRAWN BY: L. TRAXINGER 80 0 80 SCALE IN FEET ~ King County PROPOSED WORK: CREA TIE A MEANDERING CHANNEL AND AN ADDITIONAL SIDE CHANNEL, REMOVE INVASIVE VEGETATION AND PLANT NATIVE VEGETATION SHEET: 3 OF 11 DATIE: JULY 18, 2011 ------------Si ~~ ..... --------'---+-- 5c ;~ <!2 \ ~' URPOSE: MITIGATION FOR MAY CREEK DRAINAGE IMPROVEMENT AND CONTROL SEDIMENT DELIVERY TO MAY CREEK IRECTIONS TO SITE: SOUTH ON SE MAY ALLEY RD, GO APPROX. 300 FT PAST 150TH L SE, TO LONG MARSH CREEK CROSSING AT 5019 SE MAY VALLEY RD. OR TRAVELING ORTH, APPROX. 300 FT BEFORE 150TH PL S ATUM: HORIZ.: N AD 83 VERT.: NA VD88 IO N ,,., IO N ,,., PROJECT llllE: 5c 0 N ,,., IO ,,., 0 ~ ,,., w l\-f--+---t--3 ::, u 0 N ,,., §:--+- IO ,,., 0 ,,., LONG MARSH CREEK RESTORATION SHEET TITLE: PLAN AND PROFILE VIEWS SCALE: 1 "=60' ASSISTANCE BY: D.C., WES K .. J. T. DRAWN BY: L. TRAXINGER IO 0 ,,., ~ 6 c,: Q. c., z ~ 0 0 ,,., 0 0 ,,., ROPOSED WORK: 1--w w i.J... z o- w __J <{ u VJ IO O ,,., ,,., w ~ c., ~ King County CREATE A MEANDERING CHANNEL AND AN ADDITIONAL SIDE CHANNEL, REMOVE INVASIVE VEGETATION AND PLANT NATIVE VEGETATION SHEET: 4 OF 11 DATE: JULY 18, 2011 I I I I I ll I I I I 11 I I I I I I I ·~ [ r t;_, r I L r r - I L 8 ci N Lu Lu 0:: (/) ~"' u ' -' :::r:: Lu oV):z:lO "-· C! c::: z: ,11 <'I<(<(~ :::::E :::r:: 0 u ~""" ~ C) -1 Z-c:,: Ou 0 _,_ --C! CL 00 >- THE EXISTING TOPOGRAPHIC AND PHYSICAL FEATLRES SHOWN ON THIS PLAN ARE BASED ON A COMBINATION OF FIELD OBSERVATIONS AND LAND SURVEY USING ASSUMED BASIS OF COORDINATES I- PROJECT TITLE: '-'~\ z"' F ~ . ' ,- I PURPOSE: MITIGATION FOR MAY CREEK DRAINAGE IMPROVEMENT AND CONTROL SEDIMENT DELIVERY TO MAY CREEK DIRECTIONS TO SITE: SOUTH ON SE MAY ALLEY RD, GO APPROX. 300 FT PAST 150TH LONG MARSH CREEK RESTORATION L SE, TO LONG MARSH CREEK CROSSING AT 5019 SE MAY VALLEY RD. OR TRAVELING ORTH, APPROX. 300 FT BEFORE 150TH PL S DATLM: HORIZ.: NAD 83 VERT.: NAVD88 SHEET TITLE: SECTION VIEWS SCALE: 1 "=5' ASSISTANCE BY: D.C., WES K., J.T. DRAWN BY: L. TRAXINGER 0 0 0 N 0 q ~ io I: 0 ·~ 0 q ~ ;;: ~ 0 0 00 8 1-w w u... z o- LO z 0 1-u w _J <{ u CJ) ::.:: Lu w (/) w_, Uo::: Lu ~ Z',; >-z <(<( ~i5 Lu C, (/) ROPOSED WORK: ~ King County CREA TE A MEANDERING CHANNEL AND AN ADDITIONAL SIDE CHANNEL, REMOVE INVASIVE VEGETATION AND PLANT NATIVE VEGETATION SHEET: 5 OF 11 DATE: JULY 18, 2011 • • OIMTS IN ALTER FABRIC SHA1.L BE SPLICED AT POSTS. USE STAPLES, WIRE RINGS. OR EOUNALENT TO ATIACH FABRIC TO POSTS 2"X2" BY 14 Go. WIRE OR EQUNAlENT, If STAHOARO STRENGTH FABRIC USED FILTER FABRIC ~»~~~%?"a, -1 f-c::::f---''-"""'--,-C>-ll ~INIMUM ··x•· TRENcH c,su: BELOW Fl.OTATION ),l~---GIROMMETS LACED TOGETHER wrTH MANILA ROPE LJ BACKFILL TRENCH WITH NATh'E SOIL 'J/4•-,;5• WASHED GRAVEL HAIN TENSIONED TliROUGH SfR POST SPACING MAY BE INCREASED TO 8' IF WIRE BACKING IS USED NOT!: nLTER FABRIC FtNCfS SHALL BE INSTALLED ALONG CONTOUR WHENEVER POSSIBlE 2•x4" WOOD POSTS, STEEL FENCE POSTS, REBAR, OR EQUNAI..ENT ~ ..... -CHAIN PLATES, W. HOOK AND RING CONNECTION "8"0 CUL~, { EXISTING SILT FENCE DETAIL NTS -..... -.. STEEL PLATE AND/OR COFFER DAM ·-........... .., 2" SECONDARY PUMP (4" PUMP ON STANDBY FOR WET CONDITIONS) (T\ 7 ..__, • PRIMARY PUMP .._ ______ ....,_ rBoEYOstNABLED Al'Tt\~.!IE:. (6" PUMP ON ..... ,. • ._ """ ANDBY' FOR WET fl.Ali AREA (DOWNSJ'REAM) CONOmONS) SILT CURTAIN (TYPICAL) ffi IIOT TO SC.lil 7 STEEL PLATE OR SANDBAGS ACROSS WIDTH OF CHANNEL STEEL PLATE AND/OR SANDBAGS WllH 40 MIL POLYETH'YLENE SHEETING OR EQUIVALENT ~ TEMPORARY STREAM BYPASS PUMP. DAM AND PIPE DETAIL CD 4"-8" QUARRY SPALLS OVER GEOTEXT!LE FABRIC TEMPORARY CONSTRUCTION ACCESS HTS CD HTS CONSIRIJCTIDN ACCESS NOIES: 1. THE ENTRANCE SHALL BE MAINTAINED 1N A CONDITION WHICH WILL PREVENT TRACKING OR FLOW OF MUD ONTO PUBLIC RIGHT-OF-WAY. THIS MAY REQUIRE PERIODIC TOP DRESSING WITT-I r STONE, AS CONDITIONS DEMAND, AND REPAIR AND/OR CLEAN-OUT OF ANY STRUCTURES USE TO TRAP SEDIMENT. 2. ALL MATERIALS SPILLED, DROPPED. WASHED OR TRACKED FROM VEHICLES ONTO ROADWAYS OR INTO STORM DRAINS MUST BE REMOVED IMMEDIATELY. PROVIDE FLAGGING FOR CONSTRUCTION VEHICLES ENTERING ANO LEAVING SITE. 3. COORDINATE WITH THE PROPERTY OWNER REGARDING THE EXACT SIZE AND LOCATION OF THE TEMPORARY CONSTRUCTION ACCESS TO AVOID DISRUPTION Of THE HORSE BOARDING ACTIVITY ON THIS PROPERTY. REMOVAL OF THE QUARRY SPALLS MAY BE REQUIRED AFTER THE CONSTRUCTION. THE EXISTING TOPOGRAPHIC AND PHYSICAL FEATURES SHOWN ON THIS PLAN ARE BASED ON A COMBINATION OF FIELD OBSERVATIONS AND LAND SURVEY USING ASSUMED BASIS OF COORDINATES DEPENDING ON WEATHER CONDITIONS, AT THE DlRECTlON OF THE ~ 4. HOG FUEL MAY BE SU9ST1TUTED FOR THE QUARRY SPALLS ~ WLRD SITE REPRESENTATI\/£. King County URPOSE: MITIGATION FOR MAY CREEK DRAINAGE IMPROVEMENT AND CONTROL SEDIMENT DELIVERY TO MAY CREEK DIRECTIONS TO SITE: SOUTH ON SE MAY ALLEY RD, GO APPROX. 300 FT PAST 150TH L SE, TO LONG MARSH CREEK CROSSING AT 5019 SE MAY VALLEY RD. OR TRAVELING ORTH, APPROX. 300 FT BEFORE 150TH PL S AWM: HORIZ.: N AD 83 VERT.: NAVD88 -....... ¥ •• w.2.:--rm PROJECT TITLE: LONG MARSH CREEK RESTORATION SHEET TITLE: TESC DETAILS SCALE: NO SCALE ASSISTANCE BY: D.C., WES K., J.T. DRAWN BY: L TRAXINGER m;;; ±·nit ROPOSED WORK: CREA TE A MEANDERING CHANNEL AND AN ADDITIONAL SIDE CHANNEL, REMOVE INVASIVE VEGETATION AND PLANT NATIVE VEGETATION SHEET: 8 OF 11 DATE: JULY 18, 2011 rt bit . t iidtfti 'Ii··· I l1l I n I I I I I I I I I I 11' I :1 I I I I I URPOSE: MITIGATION FOR MAY CREEK DRAINAGE IMPROVEMENT AND CONTROL SEDIMENT DELIVERY TO MAY CREEK DIRECTIONS TO SITE: SOUTH ON SE MAY ALLEY RD, GO APPROX. 300 FT PAST 150TH L SE, TO LONG MARSH CREEK CROSSING AT 5019 SE MAY VALLEY RD. OR TRAVELING ORTH, APPROX. 300 FT BEFORE 150TH PL S ATUM: HORIZ.: NAO 83 VERT.: NAVD88 PROJECT TITLE: LONG MARSH CREEK RESTORATION SHEET TITLE: TESC PLAN SCALE: 1 "-50' ASSISTANCE BY: D.C .. WES K., J.T. DRAWN BY: L. TRAXINGER ROPOSED WORK: CREA TE A MEANDERING CHANNEL AND AN ADDITIONAL SIDE CHANNEL, REMOVE INVASIVE VEGETATION AND PLANT NATIVE VEGETATION SHEET: 7 OF 11 DATE: JULY 18, 2011 OINTS IN ALTER FABRIC SHAU. BE SPLICED AT POSTS. USE STAPLES, WIRE RINGS. OR EQUN'M.ENT TO ATTACH FABRIC TO POSTS 2"'X2• BY 14, Ga. WIRE OR EQUIVALENT, IF STANDARD STRENGTH FABRIC USED FILTER FABRIC " ION CA8lE BELOW F'lOTATION ' ~~ ioH--GROMMETS LACED TOGETHER WITH w.NILA ROPE 6'~ -;-""" 1-::::J--''--''°"'--r-!:;:>-I I ........._MINIMUM •··•· mENCH IJ BACKFILL TRENCH WITH NATll/E SOIL 3/4•-,;5• WASHED GRAVEL POST SPACING MAY BE INCREASED TO B' IF 'NIRE BACKING IS USED T'DiSIONED TiiROUGH STR NOTE: FILTER FABRIC FENCES SHALL BE INST~ ALONG COt<ll'OUR WHENEVER POSSIBLE 2•x4• WOOD POSTS, srm FENCE POSTS, REBAR, OR EQUIVALENT BAU.AST CHAIN PLATES. VIA HOOK ANO RING CONNECTION SILT FENCE DETAIL NlS STEEL PLATE AND/OR COFFER DAM ·, ···~ ........ 2• SECONDARY PUMP (4• PUMP ON STANDBY FOR WET CONDITTONS) • 7;~M:U~N '--------c-~~tB~HAN:~ ANDBY FOR WET .e&.At:i AREA (DOWNSTREAM) CONOJTIONS) 7 ..._, SILT CURTAIN (TYPICAL) {3'\ NOTTOSCAI..E 7 STEEL PLATE OR SANDBAGS ACROSS WIOlH OF CHANNEL STEEL PLATE AND/OR SANDBAGS WllH 40 MIL POLYETHYLENE SHEETING OR EQUrYAL.ENT ~ TEMPORARY STREAM BYPASS PUMP. DAM AND PIPE DETAIL ED 4"-8" QUARRY $PALLS OVER GEOTEXTILE FABRIC TEMPORARY CONSTRUCTION ACCESS NlS CD NlS CONSTRUCTION ACCESS NOTE:'.$· 1. THE ENTRANCE SHALL BE MAINTAINED IN A CONOmON WHICH Will PREVENT TRACKING OR FLOW OF MUD ONTO PUBLIC RIGHT-OF-WAY. THIS MAY REQUIRE PERIODIC TOP DRESSING WITH 2" STONE, AS CONDITIONS DEMAND, AND REPAIR AND/OR CLEAN-OUT OF ANY STRUCTURES USE TO TRAP SEDIMENT. 2. ALL MATERIALS SPILLED, DROPPED, WASHED OR TRACKED FROM VEHICLES ONTO ROADWAYS OR INTO STORM DRAINS MUST BE REMOVED IMMEDIATELY. PROVIDE FLAGGING FOR CONSTRUCTION VEHICLES ENTERING AND LEAVING SITE. J. COORDINATE WITH THE PROPERT'r' OWNER REGARDING THE EXACT SIZE AND LOCATION OF THE TEMPORARY CONSTRUCTION ACCESS TO AVOID DISRUPTION OF' THE HORSE BOARDING ACTIVITY ON THIS PROPERTY. REMOVAL OF THE QUARRY SPALLS MAY BE REQUIRED AFTER THE CONSTRUCTION. THE EXISTING TOPOGRAPHIC AND PHYSICAL FEATURES SHOWN ON THIS PLAN ARE BASED ON A COMBINATION OF FIELD OBSERVATIONS AND LAND SURVEY USING ASSUMED BASIS OF COORDINATES 4. HOG fUEL MAY BE SUBSTITUTED FOR THE QUARRY SPALLS DEPENDING ON WEATHER CONDITIONS, AT THE DIRECTION OF THE WLRD SITE REPRESENTAHVE. King County URPOSE: MITIGATION FOR MAY CREEK DRAINAGE IMPROVEMENT AND CONTROL SEDIMENT DELIVERY TO MAY CREEK IRECTIONS TO SITE: SOUTH ON SE MAY ALLEY RD, GO APPROX. 300 FT PAST 150TH L SE, TO LONG MARSH CREEK CROSSING AT 5019 SE MAY VALLEY RD. OR TRAVELING ORTH, APPROX. 300 FT BEFORE 150TH PL S DATUM: HORIZ.: NAO 83 VERT.: NA VD88 PROJECT TITLE: LONG MARSH CREEK RESTORATION SHEET TITLE: TESC DETAILS SCALE: NO SCALE ASSISTANCE BY: D.C .. WES K .. J.T. DRAWN BY: L. TRAXINGER PROPOSED WORK: CREA TE A MEANDERING CHANNEL AND AN ADDITIONAL SIDE CHANNEL, REMOVE INVASIVE VEGETATION AND PLANT NATIVE VEGETATION SHEET: 8 OF 11 DATE: JULY 18, 2011 I I I I I JI I I I I I I I I I I I I I I I I I I I I I ., MITIGATION SEQUENCE: 1. PRIOR TO MITIGATION CONSTRUCTION, CLEARING LIMITS SHALL BE CLEARLY IDENTIFIED WITH ORANGE PLASTIC FENCING. KING COUNT(S BIOLOGIST SHALL VERIFY ANO APPROVE FENCE LOCATIONS PRIOR TO CONSTRUCTION. 2. CONTRACTOR SHALL ARRANGE TO MEET ON SITE WITH ENGINEER AND BIOLOGIST PRIOR TO THE COMMENCEMENT OF CONSTRUCTION ACTIVITIES TO DISCUSS ACCESS, LIMITS OF WORK ~~-~-AND METHODS. 3. MITIGATION PLANTING PLANS REPRESENT A CONCEPTUAL PLANT LAYOUT. FINAL PLANT LOCATIONS SHALL BE DETERMINED AT THE TIME OF PLANTING BY THE BIOLOGIST. 4. WITHIN ALL DISTURBED AREAS TO BE PLANTED OR SEEDED, PROVIDE AND INSTALL FOUR (4) INCH DEPTH OF COMPOST ROTOTILLED TO A TWELVE (12) !NCH MINIMUM DEPTH. 5. ALL PLANTS SHALL BE NURSERY GROWN A MINIMUM OF ONE YEAR. PLANT MATERIAL IS TO BE SUPPLIED BY COMMERCIAL NURSERIES THAT SPECIALIZE IN PLANTS NATIVE TO THE PUGET SOUND REGION OF THE PACIFIC NORTHWEST. PLANT SUBSTITUTIONS ARE SUBJECT TO APPROVAL BY KING COUNTY'S BIOLOGIST. 6. PLANTING SHALL TAKE PLACE DURING THE PLANT DORMANCY PERIOD (NOVEMBER 1ST TO MARCH 1ST), OR AS DIRECTED BY KING COUNTYS BIOLOGIST. 7. THE CONTRACTOR SHALL BE RESPONSIBLE FOR DISPOSING Of ALL DEBRIS AND EXCESS SOIL EXCAVATED BY THIS PROJECT. 8. CONTRACTOR SHALL VERIFY THE LOCATION OF ALL UTILITIES PRIOR TO EXCAVATION. 9. EXISTING AREAS DISTURBED BY CONSTRUCTION ACTIVITIES AND NOT SHOWN TO BE RE-VEGETATED ON THESE PLANS SHALL BE RESTORED AND SEEDED. AS DIRECTED BY THE ENGINEER. 10. DISCREPANCIES BETWEEN THE PLANS AND SITE CONDITIONS SHALL BE BROUGHT TO THE ATIENTION OF THE ENGINEER AND BIOLOGIST PRIOR TO PROCEEDING. ,, · · 1 I. TO TACKIFIER, HERBICIDE OR FERTILIZER SHALL BE USED IN .... <,:-_,-..... THE STREAM PLANTING AREAS. THE EXISTlNG TOPOGRAPHIC AND PHYSICAL FEATURES SHOWN ON Tl,IS PLAN ARE BASED ON A COMBINATION OF FIELD OBSERVA TlONS AND LAND SURVEY USING ASSUMED BASIS OF COORDINATES 40 0 SCALE IN FEET 40 ~ King County URPOSE: MITlGATION FOR MAY CREEK DRAINAGE IMPROVEMENT ANO CONTROL SEDIMENT DELIVERY TO MAY CREEK DIRECTIONS TO SITE: SOUTH ON SE MAY ALLEY RD, GO APPROX. 300 FT PAST 15011, L SE, TO LONG MARSH CREEK CROSSING AT 5019 SE MAY VALLEY RO. OR TRAVELING ORTH, APPROX. 300 FT BEFORE 150TH PL S DATUM: HORIZ.: NAO 83 VERT.: NA VD88 PROJECT TITLE: LONG MARSH CREEK RESTORATlON SHEET TITLE: PLANTING PLAN ANO NOTES SCALE: 1 "-40' ASSISTANCE BY: 0.C., WES K., J.T. DRAWN BY: L. TRAXINGER PROPOSED WORK: CREA TE A MEANDERING CHANNEL AND AN ADDITIONAL SIDE CHANNEL, REMOVE INVASIVE VEGETATION ANO PLANT NATIVE VEGETATION SHEET: 9 OF 11 DATE: JULY 18, 2011 TREE STAKING "ARBOR TIE" OR APPROVED SUBSTITUTE----~ a·-o· "svc· LODGE POLE PINE STAKE, 2" DIA. (1 PER TREE) DRIVEN INTO UNDISTURBED DIAGONALLY SUBSOIL MIN. 24" DEPTH--------~ llilIE: STAKE ALL TREES 4' AND TALLER. BACKFILL WITH MIXTURE OF 1 /3 COMPOST AND 2/3 NATIVE SOILS. WATER AND TAMP TO REMOVE AIR POCKETS. SCARIFY SIDES OF PLANTING PITS PRIOR TO BACKFILLING. PLANTING HOLE TO BE 2 X DIA. OF ROOTBALL PLANIT SO THAT TOP OF ROOT BALL IS EVEN WITH THE FINISHED GRACE FORM SAUCER WITH 3" CONTINUOUS RIM CONE OF HAND FIRMED TOPSOIL FOR ALL PLANTS CONIFEROUS TREE PLANTING 2" DEPTH AS A MULCH. KEEP MULCH AWAY FROM MAIN STEM ----~ FORM SAUCER WITH 3 • CONTINUOUS RIM NTS PLANT AT SAME LEVEL AS GROWN. TOP OF ROOTBALL TO BE LEVEL W/ FINISH GRADE. GRADE tlQIE; llilIE: DECIDUOUS TREES SHALL HAVE TWO STAKES FOR SUPPORT. INSTALLED PERPENDICULARLY PER U.S. HORT. STANDS. :_ITT=m'---~ 'ill BACKFILL WITH MIXTURE OF 1- 1/3 COMPOST & 2/3 EXISTING SOIL PRUNE DEAD OR BROKEN ROOTS. SLICE THROUGH ROOTS CIRCLING THE BALL. SPREAD ("BUTTERFLY") ROOTS ON BARE ROOT & CONTAINERIZED MATERIAL. NATIVE SOILS. WATER AND TAMP TO REMOVE AIR POCKETS. SCARIFY SIDES OF PLANTING PITS PRIOR TO BACKFILLING. ---~ x DIAMETER ROOTBALL. MIN. CONE OF HAND FIRMED SOIL FOR ALL PLANTS "BUTTERFLY" ROOTBALL SMALL TREE, SHRUB ---'A:,cN.,_,,Dc.......,cG,.,_R O""U,,,.,N..,_,D'-"'C""-0..!...V E:.!R.,___._P-=L!..!.A N"-T,..,,,I N..,_,G'--_ _,_{2\-'2=---l MIN. 12 NODES NTS BELOW GRADE PAINT OR DIP EXPOSED ENDS OF LIVE STAKE WITH WHITE LATEX PAINT PRIOR TO INSTALLATION llilIE: POKE HOLE IN SUBGRADE WITH STEEL BAR. CAREFULLY PLANT STAKE IN HOLE. DO NOT BREAK OFF LEAF NODES. CAREFULLY FIRM SOIL AROUND INSTALLED LIVE STAKE TO REDUCE AIR POCKETS. THE EXISTING TOPOGRAPHIC AND PHYSICAL FEATURES SHOWN ON THIS PLAN ARE BASED ON A COMBINATION OF FIELD OBSERVATIONS AND LAND SURVEY USING ASSUMED BASIS OF COORDINATES BEVELED END ( 45°) IN SOIL DO NOT LET DRY OUT URPOSE: MITIGATION FOR MAY CREEK DRAINAGE IMPROVEMENT AND CONTROL SEDIMENT DELIVERY TO MAY CREEK IRECTIONS TO SITE: SOUTH ON SE MAY ALLEY RO, GO APPROX. 300 FT PAST 150TH L SE, TO LONG MARSH CREEK CROSSING AT PROJECT TITLE: 5019 SE MAY VALLEY RD. OR TRAVELING ORTH, APPROX. 300 FT BEFORE 150TH PL S DATUM: HORIZ.: NAO 83 VERT.: NAVD88 LONG MARSH CREEK RESTORATION SHEET TITLE: PLANTING DETAILS SCALE: NOT TO SCALE ASSISTANCE BY: D.C .. WES K., J.T. DRAWN BY: L. TRAXINGER LIVE STAKE INSTALLATION: INSTALL LIVE STAKES AT MIN. 36" SPACING. INSTALL PER DETAIL. ~ King County PROPOSED WORK: CREA TE A MEANDERING CHANNEL AND AN ADDITIONAL SIDE CHANNEL, REMOVE INVASIVE VEGETATION AND PLANT NATIVE VEGETATION SHEET: 10 OF 11 DA TE: JULY 18, 2011 I I· I I I I. I I I Ii fl !if I! I I I Sclontlftc Name Common Quantity Size Conditions Plant Spacing Name Long Marsh CIMk * Thuje plicata Western 7 Container min 18" ht, full, dense foliage, High flow channel, slope edge locate in cluster of willows Reel Cedar symmetrical crown I 0 Betula papyrtfera PaperBln::h 9 B&B 5-6' ht, full, dense foliage, symmetrlcal crown High flow channel wilhln 50 feet of May Creek 0 F raxlnus latifolia Oregon Ash 10 B&B 5-6' ht, fun, dense foliage, symmetrical crown High flow channet base of slope I 0 Cornus serlcea Red Osier 27 Container 1a· -21 • ht and spread, min lwO stems Ck.Islets of three on high flow channel Dogwood 0 Acer clrclantum Vine Maple 30 Container 18" -21· ht and spread, min lwO stems Clustera of three on high flow channel I ~ Salix laslandra Pacific 55 LM;I slake, min 36" long at%" to'%• diameter, min 3 ·oc staggered. Stakes driven Into high flow chaMel Willow 12 lateral buds per stake d istriboted along creek () Salix sltchensls Sitka WiRow 55 Live stake, min 36" long at%" to%· diameter, min 3 'oc staggered Stakes driven Into high flow dlannel 12 lateral buds per stake distributed along creek I 0 Rubus spectabafts Salmonberr 30 Container 1s· -21· ht and 1 S-spread, dense, Clusters of three on h)gh flow channel y multiple slems • Symphoricarpos Snowberry 30 Container 15"·18" ht spread, full Clusters of three on upper bank of hfgh flow channel albus I !l!I Rosa nutkana Nootka 30 Container 15" -18· ht spread, full Clusters of three on upper bank of high flow channel Rose Polystlchum munitum Western 40 1 Gallon container min 3 fronds Distnbuted I Sword Fem Achilles m1118/ollum Yaoow 40 10 cubic Inch Plugs or 4" pot Dislributed Aruncus dlolcus Goat's 40 10 cubic Inch Plugs or 4"pot Distributed Beard Tellima grandlflora Fringecup 40 10 cubic inch Plugs or 4" pot Dlstributed Carex lenticularis Shore 30 10 cubic inch plugs Clusters adjacent to low now channel I Sedge Scripus micmcarpus SmaD-fruited 30 10 cubic inch plugs Clusters adjacent to low llow channel II Bulrush Oxalls oregano Wood-sorrel 50 4 "pot Distributed I I May Creek Side Channel • Thuja plJcata Western 3 Container min 18" ht, full, dense foliage, "Island" between main and side channel Red Cedar symmetrical crown 0 Comus serlcaa Red Osier 3 1 gal Container min two stems "Island" between main and side channel Dogwood I Symphorlcarpos Snowberry 6 1 gal Container min two stems "Island" between main and side channel • a!M Carex lenticutarts Shore 6 1 O cubic inch plugs low bank along island between main and side channel I Sedge Scripus mlcrocarpus Small-fruited 6 1 O cubic Inch plugs low bank along lslDnd betwoon main and side chaMel Bulrush • Salix losl!mdra Pacific 20 Live stake, min 36" long at 'h" to V. • diameter, min 3 ·oc staggered. Stakes drtvcn Into banks distributed Willow 12 lateral buds per stake along island between May Creek main and side channel I· I ,, Salix sltchensls Sitka Willow 20 live stake, min 36-long at 'I.," to~• diameter, min 3 'oc staggered Stakes driven Into banks distributed 12 lateral buds per stake along creek w King County I I PURPOSE: MITIGATION FOR MAY CREEK PROJECT TITLE: PROPOSED WORK: I DRAINAGE IMPROVEMENT AND CONTROL LONG MARSH CREEK RESTORAllON CREATE A MEANDERING CHANNEL SEDIMENT DELIVERY TO MAY CREEK AND AN ADDITIONAL SIDE CHANNEL, DIRECllONS TO SITE: SOUTH ON SE MAY SHEET TITLE: REMOVE INVASIVE VEGETATION AND VALLEY RD, GO APPROX. 300 FT PAST 150TH PLANT NAllVE VEGETAllON PL SE, TO LONG MARSH CREEK CROSSING AT PLANTING SCHEDULE 15019 SE MAY VALLEY RD. OR TRAVELING NORTH, APPROX. 300 FT BEFORE 150TH PL S DATUM: SCALE: NOT TO SCALE HORIZ.: NAO 83 ASSISTANCE BY: D.C., WES K .. J.T. SHEET: 11 OF 11 VERT.: NAVD88 DRAWN BY: L. TRAXINGER DATE: JULY 18, 2011 I I I I I I I I I I ·1 . •. . . ' . : . -··· ·I 'I ,.l1l.· ' ' i' .. , ', \I I I I -1 . . .GeoENGIN~E·R~ •--.:_--.. - . . - . --·- •, \ . . \' '. '; ·. ' . ' ·, . ', \ \ \ '. \ ! , I • , • • \ ' \ \ \ 1 \ \ • 1 \ ' ' ' \ I , ' ' I ' 1 ' \ ' I l I \ I \ ' ·. '. ' • \ ' I \ ' \ I \ l I '1 '1 ',i l I I I I I II I, I '1 '1 \ Ii II I 1 1 I '. I ! I I ! I 1 ; 1 i I f I I I I I ' I I / I I I ' I I I I I I ' I I I I I ' ' I I I ' · i : ,' : , · : :' : : : : : i I / : i' ! 1 : ·' : 1 1 c' ·,ty of Renton {J,''I /1•·•/•/,/ j,i '.'/;, / ! I ' I I ,' • ' I .J • • I I ' ' ,, i / I 1 ' ' ·' , I · · ' · · : Planning Division ' ' f FEB 1 9 tU13 FINAL DRAFT MAY CREEK DRAINAGE AND RESTORATION PLAN KING COUNTY, WASHINGTON DECEMBER 19, 2008 FOR KING COUNTY WATER AND LAND RESOURCES DIVISION MID-PUGET SOUND FISHERIES ENHANCEMENT GROUP . . ~. ./ - ----- -:---=-:_: ~_-_;. __ ~ ' : ~ ' .. \ . ' '. 1\,\\·;, ,·, '· .. \_,\ ,, ', • I t I 1 ' ' I ' < . \ , " \ I! I I l •\\I '' 11. '' \ \1 \ \ L 1 i.' I Ii '1 'I l 11.1 \ '1 \ '1'1 \ i1'.'i', '\'. I • ii/ I ' I I ' I ' I • I' ; : "f 1, ' I 'I ' I I ' ' . '' 't I' ' 'I I ! /, I i ', , I• 1 i,,, , , , I, 1 '1 ' ' ,' / / ' i' ,' I ' / ' ' l I I ! r ' ' ,' ' J ' I ' / ; • / / : J ,_:,,, , , ' : .· , ,· I , { ' : ' ' i / .. , . . ' ·' ' /, : i ' ! ' ' / .. ' ·'.' . ,' I.' , ' , :~ -~ ',· ,' ,· . . File No. 1()791.0()5:00 f'inal Draft ii/lay Cree!< Drainage anol Restoration Plan King County, Washington File No. 10791-005-00 December 19, 2008 Prepared for: King County Water and Land Resources Division Mid-Puget Sound Fisheries Enhancement Group 7400 Sand Point Way NE BLDG 30, RM 202 Seattle, Washington 98115 Attention: Troy Fields, Executive Director Prepared by: GeoEngineers, Inc. 8410 164111 Avenue NE Redmond, Washington .98052 (425) 861-6000 In hart luvlal Geomorphologlst JTM:MAR:iu •. i . ,, I Rl;D P;\10\10791005100\Finals\Dcccmbcr 200S Final IJrall\1079100500 Mny Cr<ck.doc C<>p)TightO 200R h)· GcoEnglnccr.i, Inc. Ail ri31ti., reserved. Proprietary Nutitc; The \.VfllL'nll ur I.his .Jucuntt"nl urc p1upcii:wry 10 Ocofingi11CCn. Inc. and nrc intrndcd solely rot· use by our climt!!i and their dr.•ign tcnm..1 to _cvn.lWl.tc GeaEna:inccts' cnpa.bilitics and u11d1.-rsumdlna of project rcqulremtnts BS lhcy rela10 10 ·performing. the seNices proposed for a 1pccific: prQiect. Copies of this dOl."WTicnl or iu: ~unle'nb muy nut be di~!ust.'1 lo w1y 1.'thcr,panies wilhout lhc \\Tittert 1.'llll~nl ofG~Enginttr3. FIia No. /079/,00J-OO fl I I ~ II I I I I I I I I I I I I I I I I I I I TABLE OF CONTENTS Page No. INTRODUCTION ........................................................................................................................................... 1 PROJECT BACKGROUND ........................................................................................................................... 1 PROBLEM STATEMENT AND PROJECT OBJECTIVES ............................................................................ 2 PROJECT APPROACH ................................................................................................................................ 3 TECHNICAL INFORMATION UPDATES ........................................................................................... 4 ENVIRONMENTAL SETTING ....................................................................................................................... 5 REGIONAL SETTING ......................................................................................................................... 5 Geologic History and Topography ............................................................................................. 6 Geology ..................................................................................................................................... 6 Basin Hydrology ........................................................................................................................ 7 MAY CREEK BASIN SUBAREAS ..................................................................................................... 11 MAY VALLEY SUBAREA CONDITIONS .......................................................................................... 11 Historic Valley Condition .......................................................................................................... 12 Existing Valley Conditions ....................................................................................................... 13 MAY VALLEY SUBAREA REACH CHARACTERISTICS ................................................................. 15 Reach 1. Subarea boundary (RM 3.9) to 148'h Avenue SE bridge (RM 4.5) ......................... 16 Reach 2. 148'h Avenue SE (RM 4.5) to Colasurdo/Fisher boundary line (RM 5.35) .............. 18 Reach 3 Colasurdo-Fisher Fence Line (RM 5.35) to 164th Avenue SE (RM 5.93) ............... 19 Reach 4. 164th Avenue SE (RM 5.93) to Hendrix Creek Confluence Area (RM 6.35) ........... 21 Reach 5. Hendrix Creek Confluence Area (RM 6.35) to SR-900 Bridge (RM 7.02) .............. 22 Reach 6. SR-900 Bridge Crossing (RM 7.02) to Upper May Valley Subarea Boundary ....... 24 RESTORATION CONCEPTS ..................................................................................................................... 25 DIRECT CHANNEL MODIFICATION ............................................................................................... 25 INDIRECT CHANNEL MODIFICATION ............................................................................................ 25 In-stream Structures ................................................................................................................ 26 Bank Structures ....................................................................................................................... 27 In-Stream Nutrient and Substrate Management... ................................................................... 27 OFF-CHANNEL MODIFICATIONS ................................................................................................... 27 FEASIBILITY OF RESTORATION ACTIONS ............................................................................................. 28 DIRECT CHANNEL MODIFICATION ............................................................................................... 28 INDIRECT CHANNEL MODIFICATION ............................................................................................ 29 In-stream Structures ................................................................................................................ 29 Bank Structures ....................................................................................................................... 29 In-Stream Nutrient and Substrate Management... ................................................................... 30 OFF-CHANNEL MODIFICATIONS ................................................................................................... 30 RESTORATION ACTIONS AND PRIORITIZATION .................................................................................. 31 DEVELOPMENT OF RESTORATION ACTIONS ............................................................................. 31 PRIORITIZATION CRITERIA AND PROCESS ................................................................................ 32 File No. /079/-005-00 December 19, 2008 Pagei GEoENGINEERS g TABLE OF CONTENTS (CONTINUED) Page No. RECOMMENDATIONS ............................................................................................................................... 34 PRIORITIZED CONCEPTUAL PROJECTS ..................................................................................... 34 Reach 1 ................................................................................................................................... 34 Reach 2 ................................................................................................................................... 34 Reach 3 ................................................................................................................................... 35 Reach 4 ............................... , ................................................................................................... 35 Reach 5 ................................................................................................................................... 35 Reach 6 ................................................................................................................................... 35 OTHER ALTERNATIVE ACTIONS RECOMMENDED FOR CONSIDERATION ............................. 36 LIMITATIONS .............................................................................................................................................. 36 REFERENCES ............................................................................................................................................ 37 List of Tables Table 1. Overall Ranking and Rank Definitions ........................................................................................ 14 Table 2. Ineffective Flow Parameter Rankings .......................................................................................... 14 List of Figures Figure 2. Flow Hydrograph for USGS Gauge Station 12119600 -From September 1964 to July 1972 ........................ 9 Figure 3. Flow Hydrograph for Gauge Station 37a -From March 1999 to January 2007 ........................................... 10 APPENDICES Appendix A -GIS-Based Figures Figure 1 -Vicinity Map Figure 2 and 3 -In report text (see above List of Figures) Figure 4-May Creek Sub Areas Figure 5 -May Valley Habitat Features Figure 6 -May Creek Habitat Restoration -Reach 1 Figure 7 -May Creek Habitat Restoration -Reach 2 Figure 8 -May Creek Habitat Restoration -Reach 3 Figure 9 -May Creek Habitat Restoration -Reach 4 Figure 10 -May Creek Habitat Restoration -Reach 5 Figure 11 -May Creek Habitat Restoration -Reach 6 Figure 12 -May Creek Habitat Restoration -Conceptual Projects All Figure 13 -May Creek Habitat Restoration -Conceptual Projects Reach 1 Figure 14 -May Creek Habitat Restoration -Conceptual Projects Reach 2 Figure 15 -May Creek Habitat Restoration -Conceptual Projects Reach 3 Figure 16 -May Creek Habitat Restoration -Conceptual Projects Reach 4 Figure 17 -May Creek Habitat Restoration -Conceptual Projects Reach 5 Figure 18 -May Creek Habitat Restoration -Conceptual Projects Reach 6 Appendix B -Conceptual Project Descriptions Appendix C -Planning-Level Cost Estimate Details Appendix D -Report Limitations and Guidelines for Use File No. 1079/-005-00 December I 9, 2008 Page ii GEOENGINEE~ I I I I I I I I I I I I I I I I I I I I I I I I FINAL DRAFT MAY CREEK DRAINAGE AND RESTORATION PLAN KING COUNTY, WASHINGTON FOR KING COUNTY WATER AND LAND RESOURCES DIVISION AND MID-PUGET SOUND FISHERIES ENHANCEMENT GROUP INTRODUCTION GeoEngineers, Inc (GeoEngineers) was contracted by the Mid-Puget Sound Fisheries Enhancement Group (MPSFEG) to develop a Conceptual Restoration Plan (CRP) for the May Valley Subarea, located within the May Creek Basin, near Renton, Washington (Figure I, Appendix A). King County funded the development of this CRP. GeoEngineers and OTAK of Kirkland (the project team) worked with MPSFEG to develop this plan. The May Valley Subarea consists of a relatively long, narrow low-relief floodplain bounded on three sides by upland slopes. The floodplain, which is zoned for rural/agricultural use with accompanying residential and farm related structures, has a long history of flooding and is subject to multiple episodes of flooding every year. Although a natural function of the valley is to temporarily store floodwater, it is clear that storage periods have increased considerably over the past few decades, rendering valley properties virtually inaccessible and unusable until mid-summer. The extended duration is one result of the combined effects of alterations to the stream channel, riparian vegetation, floodplain wetlands and upland drainage basins, all of which have exacerbated the frequency and duration of valley flooding. This Conceptual Restoration Plan summarizes past, current, and projected future conditions in the May Creek Basin and provides an overview of proposed actions planned in the May Creek Basin. Based on this infonnation, a suite of 33 conceptual projects are recommended for consideration. If constructed, these projects will begin to address local flood control issues, degraded aquatic habitat, and other associated issues in the May Valley. King County, the City of Renton, the City of Newcastle, the State of Washington and the May Creek Citizens Advisory Committee invested personal time and energy identifying and prioritizing problems within the Basin and developing recommendations to resolve those problems. These efforts culminated in the production of the May Creek Basin Action Plan (Action Plan), finalized and adopted in April of 200 I (King County 200 I). Recommendations provided in this CRP were guided by technical information contained in the May Creek Current and Future Conditions Report (King County 1995), and on the expertise and experience of natural resource professionals and the citizens in the May Creek basin. PROJECT BACKGROUND The May Creek drainage basin is situated on the east side of Lake Washington in King County, Washington (Figure 1, Appendix A). Over the past several decades the May Creek Basin has been subject to numerous flooding issues related to urban and rural development. For example, the May Valley area is presently subject to frequent episodes of long duration flooding, the Canyon section (downstream from May Valley) is subject to increased erosion, and the entire length of the stream has experienced reduced usage by salmonids and wildlife. In order to address the many issues and problems facing the May Creek basin, King County developed the Action Plan (King County 200 I). The Plan was based on several supporting studies that reflected conditions documented in 1995. File No. /079/-005-00 December /9, 2008 Page I GEOfNGINEERSg We understand that earlier flood control planning efforts were attempted in the 1960s and 1970s. In the 1960s, a Flood Control Zone District drainage plan bond was proposed and failed due to issues regarding fees on new development, dredging, and fears that flood-proofing would increase development in the valley. In the 1970s, May Creek residents approved plans to deepen the May Creek channel and control runoff from new development onsite; however, the group had no authority to implement these proposals and no actions were taken. During this period valley residents urged King County to acknowledge that portions of the creek have been ditched, and thus mechanically created to convey both low flows and periodic flooding out of the valley. In 1980, King County prepared a drainage basin plan for the May Creek Basin in cooperation with the City of Newcastle Community Plan (King County 1980). Following completion of the Newcastle Plan, the County completed the "May Creek Current and Future Conditions Report," dated August 1995 and the "May Creek Basin Action Plan," dated April 2001 (King County 2001). We also understand that some landowners maintained some portions of the channel until the 1990s, after which regulations limited their ability to do so. PROBLEM STATEMENT AND PROJECT OBJECTIVES The CRP addresses Recommendation 5 in the May Creek Basin Action Plan (Action Plan, King County 2001), which focuses on reducing the duration of flood in the May Valley. Recommendation 5 states that successful projects must be allowable under current regulations and permitting requirements, and, to the extent possible, be implemented and maintained by valley residents. However, projects must also comply with King County Critical Areas Ordinance (CAO) codes, which specify that projects must be designed primarily to provide significant habitat elements ( channel meanders, buffer plantings and in-channel wood). Projects meeting these requirements may include flood reduction measures such as channel clearing; however, flood reduction can not be the primary purpose of the project. Based on directives posed by the King County Action Plan and CAO, the intent of this CRP is to provide a suite of projects that I) help reduce the duration of local flooding, 2) enhance fish habitat, and 3) can be implemented and/or maintained by local residents. The development of measures to eliminate or reduce, the frequency of significant flood events within the Valley is beyond the scope of this CRP. Individual projects are intended to reduce the duration of flooding from flows ranging from the 2-to 5-year recurrence interval storms. Based on information derived from the Basin Current and Future Conditions Report (King County 1995) and May Creek Basin Action Plan (King County 200 I), observed increases in both the frequency and duration of flooding are the end result of several factors, all of which are related to increases in stormwater runoff, valley topography/gradient, and sediment supply. In general, the increased runoff results in increased rates of hillslope sediment production and delivery to drainage channels, and increased rates of water and sediment transport through upper basin channels to the valley, where most of the sediment is deposited in the mainstem channel. Once there, the sediment tends to accumulate in low gradient portions of the mainstem channel, filling portions of the channel, obstructing flow, and thus reducing the conveyance capacity of the creek. lnfilled portions of the creek have become susceptible to the growth of invasive aquatic vegetation which capture more sediment and further restrict channel conveyance. Significant reductions in conveyance capacity have resulted in a significant reduction of in-channel flow storage, loss of aquatic habitat, more frequent flooding, and longer periods of post-flood recession and recovery. This condition has been further exacerbated by construction of bridge crossings, culverts and beaver dams, which impede all but the lowest flows. The primary objectives of the projects described in this Plan are provided below: o Reduce the duration of flood events in May Valley, o Increase conveyance of surface water out of May Valley, o Reduce erosion and sedimentation impacts in the Valley, FHe No. /079/-005-00 December I 9, 2008 Page2 GEoENGINHR~ i I I I I I I I I I I I I I I I I I I I I I I o Reduce the effects of hydraulic barriers created by culverts, bridges, and other obstructions, o Avoid impacts to downstream landowners, particularly those in the canyon section of May Creek, o Improve fish passage and habitat along May Creek and priority tributaries, and o Enhance the riparian and wetland functions along May Creek. PROJECT APPROACH Our approach to achieving the objectives described above includes three principle phases: I) identify and evaluate the relationship (and importance) of physical in-channel and floodplain conditions and processes to local flood duration problems, 2) develop conceptual projects designed to reestablish the dynamic equilibrium of the stream and address specific factors contributing to local flood duration problems, and 3) evaluate the expected benefits of projects to reduce flood duration, to improve habitat or to address other restoration priorities identified in Recommendation 5 of the Action Plan (King County 2001). The initial phase of this project included a review of available existing documents and studies for both the May Creek Basin and May Valley. Although this CRP focuses on projects in May Valley, all available information regarding May Creek Basin conditions were reviewed to gain an understanding of basin-scale controls on valley flooding. lnfonnation specific to geologic, geomorphic, and hydraulic processes in the upper basin and valley were reviewed to provide a more complete picture of the processes that are contributing to the observed increases in flood frequency and duration periods in the Valley. This information was also used to help identify specific problem areas in the May Valley and in the design and analysis of each project. With an understanding of Basin and May Valley conditions, the team identified projects with potential for achieving two objectives: I) improving in-channel processes and aquatic habitat, and 2) reducing flood duration periods resulting from high frequency events. All identified projects were further evaluated with respect to flood control effectiveness, implementation feasibility, permit requirements, water quality issues, landowner cooperation, cost and probability of success. Projects I through 29 described in this CRP were developed using well-established principles of ecosystem restoration, most of which are based on the premise that hydrologic, hydraulic, and geomorphic processes control stream channel form and function, as well as the development of aquatic habitat features. These projects focus on restoring key fluvial and biological processes and reconnecting habitat features within the watershed as a means of achieving, over the long term, greater flood conveyance and recovery of the ecosystem (Ehrenfeld 2000, Bates 2003). However, existing land use and infrastructure access issues within the May Valley demand more immediate solutions than can be achieved through process-based projects alone (Projects I through 29). Therefore, four projects (IFP I through IFP 4) were developed to address ineffective flow areas known to exist in the Valley. These projects focus on mechanical alteration of the channel cross section, and are intended to reduce flood duration periods and improve fish passage. It is important to understand that while these projects offer immediate benefits to flood-prone properties, the life span, (the period of effective project performance) will likely be short, given the ambient basin and reach scale conditions, unless implemented in concert with more process-based projects 1 through 29. The final list of feasible projects was selected and prioritized based on 1) proximity to areas with critical issues and 2) the ability of the projects to address CRP project objectives, including: flooding, fish habitat, erosion water quality, and sedimentation. The prioritization offers a sequencing of project implementation intended to incrementally improve conditions in the May Valley. File No. 1079/-005-00 December I 9, 2008 Page3 GeoENGINEERS g TECHNICAL INFORMATION UPDATES The project team reviewed available information provided by the Mid-Puget Sound Fisheries Enhancement Group (MPSFEG), King County, local community resources, Washington State agencies, Federal Agencies, and GeoEngineers. Where access was granted and landowners were available, the project team conducted site visits and met with landowners through the May Valley Subarea. New information was added, as necessary, to the existing project data base compiled by King County. New information included geomorphic, hydrologic, hydraulic and biologic characterizations provided in the May Creek Current and Future Conditions Report (King County 1995) and the May Creek Basin Action Plan (King County 200 I). Where new information was not available, the Conditions Report ( 1995) and Action Plan (King County 200 I) were used as primary references, supplemented with other available data. The information reviewed and used to characterize the basin, valley, and reach conditions included: ' • FEMA flood maps, o Geologic, soils and topographic maps, o Current road and parcel boundary maps. • Recent aerial black/white and infrared photography • Current critical/sensitive areas maps, • August 2007 Priority Habitat and Species (PHS) maps by Washington State Department of Fish and Wildlife (WDFW), and • Light Detection and Ranging (LiDAR) data and maps. The project team created a GIS data base and developed a LiDAR based floodplain surface topography model to update geomorphic, biologic and flooding conditions described in the May Creek Basin Action Plan. The GIS data base and LiDAR provides a basis for assessing the following: • Changes in conditions since publication of the Conditions Report (King County 1995). o Cause/effect relationships controlling flooding and ecological conditions throughout the May Valley. • Identification of channel constrictions, flow obstructions, topographic lows on the floodplains, and possible wetlands and near shore features that may represent possible project sites. The adequacy of existing data and basin information presented in the Basin Action Plan and appendices was reviewed for applicability to the objectives of the CRP. The reviewed data included assumptions and input parameters used in the HSPF and HEC-2 computer analyses. The model evaluated the area between !48'h Avenue SE and l64'h Avenue SE. The models were reviewed to: • assess how storage in the wetlands, overbank, and channel were modeled, • assess how well these natural storage areas simulate the attenuation of flood flows at vanous locations in the May Valley reach, and I [I i I I I I • evaluate how cross sections have changed, and whether there is sufficient existing information (ii throughout the May Valley to evaluate alternatives. {!I All collected data were reviewed with respect to important information gaps and/or inaccuracies. The l'ii.J ... · evaluation focused on assessing whether the description of May Creek conditions offered in the Current and t!J Future Conditions Report provides an accurate reflection of current basin conditions. As a result of the evaluation, the existing HSPF and HEC-2 model analyses were modified to more accurately reflect current fil· .. conditions using site-specific surveying. The HEC-2 model was converted to a HEC-RAS model, which is a !JI more accurate model for establishing flow rates, depths, durations, velocities and the time required for floodwaters to drain from the May Valley reach. The HEC-RAS model was also used to evaluate areas of (il.·.,'. ineffective flow and their respective water surface elevations for specific high frequency recurrence interval (I File No. 1079 J .005-00 December 19, 2008 Page4 GEOENGINHR~ I I storm events. Additional survey was conducted to provide site specific topographic information for use in the HEC-RAS computer model. The models and GlS database were used to evaluate the following: I I I I I I I I I I I I I I I I I o Channel sections affected by constrictions, such as pinch points caused by bridges, and flow obstructions such as beaver dams and undersized culverts. o Channel sections determined to have ineffective flow during high frequency (2-year recurrence) events. o Potential flood-prone areas. • Factors contributing to prolonged duration of local flooding. • Potential flood reduction sites. • Potential habitat restoration sites. • Selection of sites requiring additional engineering analysis. Field reconnaissance and data verification site visits were conducted throughout the basin and at possible project sites in the Valley. The reconnaissance included investigation of wetland and riparian conditions, channel erosion and deposition and floodplain features. Field data was added to the GIS data base and the results were used to develop project concepts included in this Plan. ENVIRONMENTAL SETTING This section generally describes the geologic processes that fanned the current structure of the May Creek Basin. It is these processes that established the current drainage pattern in the area and set the basic geologic and fluvial geomorphic structure within which each of the proposed projects for the Valley must function. The following background information was derived from the May Creek Current and Future Conditions Report dated August 1995 and the May Creek Basin Action Plan dated April 200 l. REGIONAL SETTING The May Creek drainage basin is part of the Lake Washington Watershed. The May Creek drainage system (main stem and tributaries) encompasses a 14-squarc mile (8,960 acre) area located on the east side of the Lake. Basin headwaters originate at about Elevation 1,600 feet, in the rugged foothills of Cougar and Squak Mountains. The basin is situated between the Cedar River, Coal Creek, and Issaquah Creek drainages. It serves a diverse mix of land uses ranging from planned urban communities to more sparsely settled rural residences and small farms. The Basin consists of four distinct topographic sections; from upstream to downstream these sections are 1) the steep upper foothills section, 2) the May Valley, 3) May Creek Canyon, and 4) the delta and eastern shoreline of Lake Washington. The upper foothills section is drained by several branching tributaries which join to form a single main stem channel where the steep terrain transitions to the low gradient topography of May Valley. The May Valley is situated between Elevations 550 and 660. The valley consists of a long, narrow relatively flat, floodplain oriented from southeast to northwest and bounded on the northeast and southwest by moderately inclined valley slopes. The valley slopes are drained by numerous tributaries that flow across the floodplain to join with the mainstem channel. The May Creek Canyon is a steep, narrow ravine deeply incised in the face of shoreline bluffs adjacent to Lake Washington. The Creek descends through the canyon from about elevation 550 feet mean sea level (MSL) to approximately elevation 20 feet MSL. The Delta section extends from the File No. 1079/-005-00 December 19, 2008 Page5 GEOENGINEERS _g mouth of the canyon where the creek flows across the low gradient landform of the Lake Washington shoreline and onto a small delta formed from May Creek sediment deposits Geologic History and Topography The current shape and topography of the May Creek Basin were determined primarily by large scale geologic events that took place from roughly 35 million to about I million years ago. These events included upward folding associated with tectonic uplift and mountain-building that formed the Cascade and Olympic Mountain Ranges. These same events included a west-northwest trending fold that formed Newcastle Hills, Cougar Mountain, and Squak Mountain. The May Creek basin lies on the southwest side of this fold. The topography of greater Puget Sound area and, in particular, Lake Washington, was further defined by the advance and retreat of numerous episodes of continental glaciation. Approximately 16,500 years ago advancing glacial ice flowed south into the greater Puget Sound area. As the glacial ice advanced, lowland areas were scoured to form Puget Sound, numerous adjacent lakes, and upland flat-topped plateaus. In the Lake Washington/May Creek area, the advance and retreat of the glacier resulted in the formation of an ice- scoured platform surrounded by the west and south flanks of Cougar Mountain. The scoured platform, which formed May Valley, is situated at Elevation 600 feet and drops away abruptly at the western edge to form a portion of the eastern lake bluff. During the final episodes of glacial advance and retreat, May Creek became a major meltwater drainage channel, and developed a conveyance corridor wide enough to accommodate the large volume of glacial runoff flowing into what is now Lake Washington. This ancestral stream eroded glacial deposits to a base level that forms the present-day elevation of the May Valley. The Vashon glacier continued to melt and had receded as far north as the Strait of Juan de Fuca by about 13,600 years ago. As the ice receded from more areas, drainages began to flow north out to the Strait of Juan de Fuca, lowering Puget Sound to its approximate present-day elevation. This initiated a second phase of erosion in the May Creek Basin. As water levels in Puget Sound and Lake Washington continued to lower, the mouth of May Creek eroded down to a new base elevation, exposing bedrock in the May Creek Canyon section and lower portion of the Valley. The receding glacier and meltwater erosion of the May Creek Basin created a well defined valley with steep sidewalls. The steep walls and multiple layers of glacial deposits on the valley walls were susceptible to landsliding and erosion, especially where the sandy deposits are exposed. As a result, both the valley-slopes and stream channel have been highly sensitive to erosion since the retreat of the glacial ice. With the on-set of human activity over the last 100 years, surface water runoff and stream discharge generated from within the basin has increased significantly, subsequently, increasing post-glacial erosion rates and the supply of fine sediments to the May Creek valley. Geology Three major geologic units underlie the May Creek Basin o Bedrock, comprising Cougar Mountain, Squak Mountain, Newcastle Hills and uplands in the immediate vicinity of May Valley. o Glacial-consolidated sediment deposits that form the gentle rolling plateau south of May Valley. o Unconsolidated sediments derived from the upper May Creek Basin and uplands surrounding the May Valley. File No. /0791-005-00 December 19, 2008 Page6 GEOENGINll~ fl I (I Ii I (i \I I I I I I I I I I I I I I I I I I I I I I The bedrock includes two fonnations: The Renton Formation, which consists of non-marine sandstone and claystone containing numerous coal beds, and the Tukwila Formation, consisting of andesitic volcanic sandstone, tuff, mudflow breccia and minor lava flows. Bedrock is primarily exposed at the surface in the uplands north of the valley; and at a few sites on the south and west sides of the valley. The glacial-consolidated sediments include advance outwash deposits, till and recessional outwash deposits. The advance outwash deposits were deposited in May Valley about 15,000 years ago by rivers of meltwater and in lakes that fonned along the margins of the glacier as it moved to the south. The advance outwash deposits generally consist of well-bedded sand and gravel, with almost no silt or clay. These sediments are exposed along much of the May Valley sidewalls. The sediments are susceptible to water erosion, resulting in ravines and gullies. The till was deposited from the base of the glacial ice as it moved over the advance outwash deposits. The till is composed mainly of a dense, highly compacted, poorly sorted mix of clay, silt and gravel. These deposits are typically 5 to 30 feet thick within the May Creek Basin. The till has very low infiltration and relatively high runoff rates. The recessional outwash consists of moderately to well sorted sand and gravel with little silt and sand deposited by meltwater flow of the receding glacier. Recessional outwash is exposed on the upland plateau in the southern part of the basin and along the south-trending outwash channels. These deposits vary from 0 to about 33 feet in thickness, and have moderate infiltration and runoff rates. The unconsolidated sediments composed of sand, gravel, and boulders in the basin and valley are derived from post-glacial processes including gravel mining, stream erosion as May Creek began to incise through glacial and non-glacial deposits; landsliding of glacial sediments from basin walls, weathering processes, stream erosion; and alluvial fan and debris fan development. These sediments are abundant throughout the May Valley and along the inner canyon walls of tributary creeks. In the May Creek Basin, the Valley is comprised mostly of alluvial deposits (water deposited sediment) up to 500 feet thick overlying bedrock. The west end of the valley is confined by a small notch in the bedrock where the alluvium thins out to exposed bedrock where the channel drops into the high gradient May Creek Canyon. The upper most section of the canyon (RM 0.6 to 3.9) is composed of compact advance outwash and possible bedrock. The lower portions of the canyon section are composed of sand and gravel outwash and alluvium and till. The May Creek channel has incised through the outwash and till. Further up channel erosion is slowed by the more compact outwash and possible bedrock. Basin Hydrology The May Creek drainage system includes approximately 26 miles of mapped streams, two small lakes and over 400 acres of wetlands. The mainstem of May Creek flows nearly 9 miles from its headwaters to Lake Washington. Major tributaries include the North, East, and South Forks of May Creek, Honey Creek, Indian Meadow Creek, Long Marsh Creek and Boren Creek. Two lakes, Lake Kathleen in the southeast and Lake Boren in the northwest, are also located within the Basin. The majority of the water entering the streams and lakes originates from stonnwater runoff and limited groundwater springs and seeps. The stonns are typically of long-duration and low-intensity. Average annual precipitation levels range from 44 to 49 inches. Snow occasionally falls at the higher elevations, but the snowfall has no significant impact on the hydrology of the basin. However, it should be noted that over the last several years, the occurrence of several rain-on-snow events has generated high volumes of stonnwater run-off. File No. /079/-005-00 Decemher 19, 2008 Page 7 GEoENGINEERS.J;;ii' Increases in stormwater run-off may be occurring for a number of reasons, including: o increased impervious and semi-impervious area (bedrock, glacial till, , roof tops, pavement, and compacted soils such as lawns); o possible increase in the intensity of storm events which exceed the infiltration capacity of the soil; and, o Lack of soil storage capacity due to saturated soil conditions. Estimated changes in runoff are presented in the Conditions Report (King County 1995), and is further evaluated later in this report. Modeling results presented in the Conditions Report predicted that the change from predominately forested land cover to more commercial and agricultural land use would effectively increase the basin-wide average of effective impervious area from O to 7 percent. The models also estimated that, without any changes in zoning or development regulations, the total future impervious area would likely increase to 12 percent. The increase in impervious area, as well as high ground water levels, were predicted to increase peak flows and flood durations in the valley from 15 to 20 percent, as compared to predevelopment conditions post-dieted for the 2-, 25-and 100-year events. In addition to these changes in landuse in the uplands of the basin, changes to the natural stream channels through dredge and fill activities and the removal of streamside vegetation have also changed runoff patterns, flood attenuation, nutrient assimilation, stream channel morphology and flow conveyance capabilities. GeoEngineers performed hydrologic analyses to evaluate whether run-off changes since 1990 predicted in the Conditions Report (King County 1995) have been realized as a result of development over the past IO to 15 years. The analyses required developing two streamflow hydrographs to evaluate actual runoff before and after 1990. A streamflow hydrograph represents the changes in streamflow as measured over time. Streamflow data from two gage stations on May Creek were used for hydrographic input. Gauge station 37A is located near the mouth of May Creek downstream of Lake Washington Boulevard. The project team was able to acquire intermittent flow data from this station. The U.S. Geological Survey (USGS) maintained the station from September 1964 to July 1972, producing hourly flow data (USGS Gauge # 12119600). King County maintained this station from November 1983 through April 1993, producing data at 15-minute intervals. Flow data from gauge 37A from September 1964 to July 1972 was used to represent conditions prior to the year 1990, as modeled in the Conditions Report (King County 1995). The average daily discharge in cubic feet per second (cfs) at Gage 37A from September 1964 to July 1972 is shown below in Figure 2. Gage station 378 is located near the Coal Creek Parkway SE crossing of May Creek. This station has been maintained by King County from November 1988 to present, producing flow data on 15 minute increments. Flow data from gage 378 from March 1999 to January 2007 was used to represent conditions between 1990 and the present. The average daily discharge in cfs at Gage 378 from March 1999 to January 2007 is also shown below in Figure 2 below. File No. /0791-005-00 December 19, 2008 Page8 GeoENGINEER~ I II I I I I I I I I I I I I I I I I I I I I I I I 120 I-Pre-Urbanization {1964-1972) -Post-Urbanization (1999-2007) I 100 · - 80 ! <1> e> 60 ~ ro .c ~' u "' i5 ~ 40 • J \ 20 Iv. " \.~ j J. -~ '\ -· . l -'\;J"'-.l ... ,. -- O· September October November December January February March April May June July August Month of Year Figure 2. Average daily streamflow hydrographs for May Creek, USGS Gauge Station 12119600 depicting pre (1964-1972) and post (1999-2007) urbanization periods. To further compare average annual flows an average monthly discharge hydrograph was developed for both the pre and post-urbanized period of record. To determine if there are any significant deviations from pre- urbanized condition the 95 percent Confidence Intervals were plotted for the pre-urbanized record. The 95 percent confidence intervals show a range of values where there is a 90 percent chance that the average monthly discharge will fall within that estimated range. This allows us to see if there are any statistical differences between both periods of record. Figure 3 shows the average monthly discharge graph for both the pre and post-urbanized conditions. Flow data from the two gauges were compared to evaluate whether expected changes in flow since 1990 have been realized. To compare the data, average daily discharges were compared for each pre and post- urbanized period of record. The post-urbanized period shows a 12 percent increase in average daily discharge during the runoff months of November through March. During the low flow months from April through October the post-urbanized period of record shows a 6 percent decrease in average daily discharge. When summarized throughout the year there is only estimated to be a 2 percent increase in average daily discharge. File No. /079/-005-00 December /9, 2008 Page 9 GeoENGINfERSg 70 ~-----------------~-----------------~ -Pre-Urbanization (1964-1972) -Post-Urbanization (1999-2007) 50 -;;, ~ 40 " e> ro .c ~ 30<----+-o 10 i ! ~--- _ !_ I ·-t f ! I I ., I .. , I r··-..... f_. ......... i .... o+---+-----ii---+---+---+---+---+--+---+---+--- .,.? ~·~ • ,~· ,$> Month Figure 3. Average daily streamfiow hydrographs for May Creek, USGS Gauge Station 12119600 depicting pre (1964-1972) and post (1999-2007) urbanization periods. o} ,,~ ,f The average monthly discharge graph shows that the yearly hydrograph, post-urbanized condition (1999- 2007) has a steeper rising limb. The steeper limb indicates that urban runoff reaches the basin outlet faster than runoff from the forested condition (pre-urbanized), probably in response to the presence of impervious surfaces. The post-urban hydrograph appears to peak in January, approximately the same time as for pre- urbanized conditions. August and September base flow conditions show relatively low base flows, which were also indicated by the average daily discharge analysis. There appear no significant differences between average monthly flows, however, this could be a result of individual storm events being washed out by low and base flow averages. Based on these observations, the stream flow hydrographs shown in Figure 2 appears to better portray individual storm events and was therefore used in the analysis of discharge differences between pre and post-urbanized conditions. It is important to consider that each average day and average month hydrograph has been developed using only 8 years of data, which is a relatively short period of time to perform any type of hydro logic analysis. Results for such small datasets should be construed as provisional and interpretation of results should recognize the potential for error. Figure 2 demonstrates that stream flows between 1964 and 1972 were generally higher than those measured between 1999 and 2007 during low flow events and were generally lower than post-urbanized flows during the peak runoff season. The flows for the high flow events have increased approximately 12 percent. This is slightly less of an increase than predicted in the Conditions Report (King County 1995). This increase in flow can be attributed to the lack of interception caused by the removal of forested cover as well as the File No. /079/-005-00 December /9, 2008 Page JO GeoENGINlERS _@ I I Iii "' I I I I I I I I I I I I I I I I I I I I I increase of impervious area. Conversely, the low-flow events were found to be less frequent after 1990 (1999 to 2007) as compared with events prior to 1990 (1964 to 1972). Such results arc not unusual in an urbanized basin where development leads to a significant increase in the percentage of impervious surfaces. As impervious surface area increases, a greater percentage of rainfall in the basin leaves the basin as stormwater shortly after the storm event, resulting in a decrease in infiltration of precipitation and subsequently, the groundwater table. These conditions have led to a decrease in groundwater discharge to the stream during low-flow periods of the year, resulting in lower discharges during base flow events. In summary, the May Valley basin shows evidence of urbanization as indicated by changes in the peak and timing of high and low flow events throughout the year. MAY CREEK BASIN SUBAREAS In previous studies the basin was divided into four regional subareas (Figure 4) for discussion and analysis. The four subareas arc the: • Lower Basin Subarea, which extends from the mouth of May Creek at Lake Washington upstream to River Mile 3.9 (RM 3.9), above the Coal Creek Parkway S.E. crossing; o May Valley Subarea, which includes the upper May Valley floodplain and adjacent lower valley areas from RM 3.9 to the hydrologic divide to the east; o Highlands Subarea, which includes the area lying north of May Valley and east of the Lower Basin, including the steep southern slopes of Cougar Mountain and the southwest portion of Squak Mountain; and • East Renton Plateau Subarea, which includes the area south of May Valley and east of the Lower Basin Subarea. Detailed descriptions for each of the sub-areas are provided in the Action Plan (King County 200 I). MAY VALLEY SUBAREA CONDITIONS The May Creek basin continues to experience growth in urban and suburban development. The May Valley Subarea, however, still remains mostly rural with landuses such as livestock management and quarry mining. Although the western portion of the subarea continues to experience more residential and commercial growth, the eastern portion of the basin will likely be preserved as a rural area, based on the location of the Urban Growth Area Boundary, which bisects the basin at 148'h Avenue SE. The following basin and valley conditions were discussed in the Action Plan (King County 200 I): o The dominant hydraulic function of the May Valley is to store floodwaters. The Valley is subject to long-duration flooding, likely in response to an increase in high-flow stormwater run-off events throughout the basin. • The most extensive flooding in the basin occurs within May Valley. Development, dredging and filling in the floodplain have altered natural drainage patterns, reduced natural storage areas, and placed structures in the path of drainage. Longer duration floods are projected in concert with predicted increases in storm water runoff. • Deposition of sediment derived from natural erosion occurred even before human development began to alter natural processes within the Basin. Sediment deposition has been accelerated by development because of increased stormwater flows and changes in local land cover and increased impervious surfaces. Sediment deposition is slowly reducing the capacity of May Creek in the valley, worsening flooding and degrading fish habitat. Sediment escaping the May Valley is transported as far downstream as Lake Washington. File No. /079/4 005-00 December 19, 2008 Page 11 GEOENGINEERS g • Nonpoint pollution from roads, quarries, developing sites and commercial operations, animal- keeping practices and grazing in riparian areas and failing septic systems are negatively effecting water quality and aquatic habitat in May Creek. • Development activities in the basin, including filling wetlands, increased stormwater runoff and peak flows, increased sediment and pollution in the water, and removal of coniferous forest cover, have historically degraded stream and wetland habitats. The following summaries of historic and existing valley conditions are provided to illustrate changes that have occurred in the May Valley Subarea. Historic Valley Condition May Valley is historically a natural floodplain and, as a result has historically experienced frequent and sometimes extensive flooding, even before humans began altering natural processes through the active use of the valley. The natural flooding events were altered with the advent of activities such as logging, coal mining, and agriculture. Prior to the onset of basin development, the May Valley floodplain was likely a predominately coniferous forested wetland that periodically filled with floodwaters as described in the Current and Future Conditions Report (King County 1995). May Valley was cleared and drained in the late l 800's to support agricultural and residential uses that persist to this day. The woodland area in May Valley today consists mainly of thin stands of deciduous trees and scrubs occurring at irregular intervals along May Creek, as compared to a more diverse mixture of deciduous and coniferous trees and shrubs that would have occupied the entire valley bottom prior to development. These and other practices led to the loss of vegetation, channelization of the streams, and further development onto the floodplains. These processes resulted in locally accelerated erosion, sediment deposition in stream channels, flooding of manmade structures, and loss of fish habitat. Through the years, flooding problems in the valley have worsened as a result of ongoing construction in the floodplain and development in upland areas, which have increased storm water runoff to the mainstem and tributary creeks and, subsequently, the May Valley. Sediment deposition in the valley has continued to reduce the conveyance capacity of the May Creek channel, in spite of past creek dredging conducted in attempts to temporarily improve conveyance and flood relief within the valley. The Conditions Report (King County 1995) suggests that, historically, the May Valley Subarea was drained by several well to poorly defined channels set in a forested wetland composed of mature western red cedar, Sitka Spruce, and western hemlock. The history of landuse in the valley from predevelopment to the l 960's is summarized in the following paragraph from the Conditions Report (King County 1995): "A 1909 USGS map of the area shows considerable stream meandering. USGS Maps of the 1920s indicate that some channel straightening had occurred. The earliest aerial photographs from 1936 show stream channelization to be almost as it is today, indicating that the channel was most likely straightened and dredged between 19 JO and 1936. in the 1940 's, due to extensive flooding and increased sediment loads, the ·county dredged the creek and deposited dredge material on surrounding properties. By the 1960 's sediment had again accumulated in much of May Creek." The Conditions Report also states that the 1992/1993 condition of the wetland "has actually improved substantially since 1936 as a result of the abandonment of agricultural lands and natural restoration of relatively high-quality, predominantly deciduous, forested, shrub-scrub, and emergent wetland habitats in some locations." File No. J 0791-005-00 December 19, 2008 Page 12 GeoENGIN!ER~ I I I [I I I I I I I I I • I I I I I I I I I I I Existing Valley Conditions GeoEnginecrs conducted stream reconnaissance surveys during three separate site visits in August 22, 2006, February 12, 2007 and July 19, 2007. The August reconnaissance survey was conducted during a period of low flow (approximately 2 cfs). The February reconnaissance survey was completed at a moderate flow (approximately 12 cfs), soon after and immediately prior to periods of high wintertime flows and flooding (approximately 90 cfs). Evidence of extensive flooding during periods of high flow was observed. Flooding was still occurring in some areas, with flows at or just above bankfull discharge levels. The July site visit was completed at a time of moderately-low flow (approximately 5 cfs). No areas were found to be actively flooding during the July visit. Some sections of May Creek were observed to be close to bankfull discharge levels, however, water surface elevations in some sections of May Creek were affected by in-channel obstructions (e.g. beaver dam, recd canarygrass). The purpose of the site visits were to observe and document existing physical conditions and flow patterns within the subbasin as well as sections of the creek immediately upstream and downstream of the valley. Information obtained from the site reconnaissance was later used to divide the valley into six geomorphic reaches to evaluate and describe existing conditions and to propose possible remedial projects for the reaches. Conversations with landowners, together with observations made during site visits were also used to guide the prioritization of supplemental survey work by the project team. During the July 2007 site visit, the area surrounding the l 48'h Avenue SE bridge crossing was identified as a high priority for supplemental survey work. Supplemental cross-section surveys, hydrologic and hydraulic modeling were completed in 2006 and 2007. The results of the study are summarized in the memorandum to Mid-Sound Fisheries dated November 8, 2006 and in communications used to produce this report. Attempts were made to reproduce the May Creek Future Mitigated HSPF conditions documented in the Conditions Report (King County 1995). However, modeled discharge and velocity results were generally lower than those documented in the Conditions Report (King County 1995). Several potential reasons for the discrepancies between the models include the following: • Documentation of exact parameters used in the 1995 Conditions Report were generally not available, • Exact dates over which the modeling was completed for the Conditions report were not known, • Evaporation data has been modified since the modeling was completed, • Precipitation data may have been modified since the modeling was completed, • Coefficients and other parameters used in the modeling for the 1995 Conditions Report could not be verified. Eleven discrete areas in the main channel of May Creek were identified as having ineffective flow during the supplemental survey work completed between the l48'h Avenue SE and 164 1h Avenue SE bridges. The supplemental survey work was used to refine model calibration and to better reflect current conditions. Based on model results, the project team identified four areas of ineffective flow: o Two areas near 148'h bridge (approximately RM 4.5), • Two bridges upstream from the l 48'h A venue bridge • Cottom Stables (Jones) Bridge (approximately RM 4.6) • Private bridge upstream of Cottom Stables (near the Red Barn, approximately RM 4.9). Model results identifying these four locations as discrete areas of ineffective flow confinned the findings of prior reports and observations made in the field. These areas, therefore, were deemed high priorities for flood mitigation and habitat restoration. File No. /0791-005-00 December 19, 2008 Page 13 GEOENGINEERS.i Additional hydro logic and hydraulic modeling was completed in 2008 to reevaluate areas of ineffective flow. Throughout the May Creek corridor there are numerous stretches where water is not effectively flowing downstream. These areas create many problems for the stream and adjacent land owners. Slow moving water allows for deposition of sediment within the channel. This deposition tends to fill in the channel, promote shallow flooding, and tends to raise flood elevations. Stagnant water can also allow for more active vegetation growth within the channel, which can choke and block flow. These areas of ineffective flow also increase water temperature and promote nesting areas for mosquitoes and other unwanted insects. The HEC-RAS model for the May Creek Valley was utilized in determining specific segments of ineffective flow. This analysis was conducted for a high frequency return event, and the 2-year flow was utilized to determine these areas. The Creek was analyzed and ranked for ineffective flow areas by combining three different ineffective flow indicators, from the HEC-RAS including: I) model average channel velocity, 2) in- channel conveyance, and 3) the overall top width of the water. Each parameter was ranked from zero to five, where a zero is the best rank, and five is the worst. These three rankings were then averaged to determine an overall effective flow ranking. A low ranking meant that the section of the Creek was effectively conveying water downstream while a high ranking meant the section of Creek was not effectively conveying water downstream. Table I shows the overall ranking system and defines what each rank means in terms of ineffective flow areas. Table 1. Overall Ranking and Rank Definitions Rank Rank Definition 0.0-1.0 No Ineffective Flow -~--------------- 1.1-2.0 Minor Ineffective Flow ------- 2.1-3.0 Average Ineffective Flow -------------------------- 3.1-4.0 Moderate Ineffective Flow ----------------· 4.1-5.0 Extreme Ineffective Flow The first ineffective flow indicator used in the analysis is the average channel velocity. This was used to determine areas where slow moving water was present; this condition could lead to channel deposition and excessive vegetation growth. In-channel conveyance is the second parameter used. The in-channel conveyance shows how much of the water is flowing within the defined channel; during a 2-year event the majority of the water should be conveyed within the channel's banks. The third parameter is the overall top width of the water; this parameter indicates areas where broad shallow flooding exists due to overtopping of the banks and ineffective flow conditions exit. Table 2 below shows the three parameters and their ranking levels. Fife No. /0791-005-00 December I 9, 2008 Table 2. Ineffective Flow Parameter Rankings Channel Velocity Conveyance Top Width Rank (ft/sec) (%) (ft) 5 0-1 0-20 >250 4 1-2 20-40 150-250 3 2-2.5 40-60 100-150 -- 2 2.5-3.5 60-75 50-100 1 3.5-5 75-90 25-50 0 >5 >90 0-25 Page 14 GEOENGINEERS_@ I I I I I I I [iJ (j I . . I I I I I I I I I I I I I I I I I I I I I From this ranking system four segments were identified as having moderate to extremely ineffective flow areas under existing conditions . The next step involved modeling the proposed conditions to verify the reduction of ineffective flow following mitigation. As mitigation efforts were modeled it became apparent that some ineffective flow areas were propagating upstream . Ultimately, some of the ineffective flow areas were lengthened to create a final condition where there were no adverse impacts upstream of these mitigation areas. The final four proposed mitigation segments are the following: • Segment J from RM 4.281 to 4.892, • Segment 2 from RM 5 .050 to 5.300, • Segment 3 from RM 5.477 to 6.533, and • Segment 4 from RM 6.945 to 7.296. M AY V A LLE Y SUBAR EA R EACH CHARACTE RI STICS The function of the stream channel, floodplain, and aquatic habitat in the May Valley Subarea is governed by the large-scale features described in the regional setting and May Valley Subarea sections. Any efforts to address flooding, fish habitat or other problems in the May Valley Subarea must take these fundamental influences into account. This section of the report builds upon the large-scale framework described above by describing reach and site-specific characteristics of the May Valley Subarea. These reach and site-specific features present small-scale challenges and opportunities which any proposed restoration efforts must address to be effective. The reach descriptions described below were developed from information documented in various reports and conditions observed in the study area during site visits. Reach boundaries and reach-specific features and conditions are illustrated in Figures 6-11 (Appendix A). Previous reports divided the May Valley Subarea into four units . However, for the purposes of this project, the May Valley Subarea was delineated the into 6 geomorphic reaches to better illuminate site-specific opportunities and challenges regarding flood reduction and habitat improvement for each of the 6 reaches. The extent of each or the six reaches is below from downstream to upstream: • Reach 1 -from the western May Valley Subarea boundary at River Mile (RM 3.9) upstream to the 148 1h Avenue SE bridge (RM 4.5), • Reach 2 -from the 148th Avenue SE bridge (RM 4 .5) upstream to the Colasurdo/Fisher prope rty fence line (RM 5.35), • Reach 3 -from the Colasurdo/Fisher fence line (RM 5 .35) upstream to the 164th Avenue SE bridge (RM 5.93), • Reach 4 -from the 164th Avenue SE bridge (RM 5 .93) to the Hendrix Creek Confluence Are a (RM 6 .35), • Reach 5 -from the Hendrix Creek Confluence Area (RM 6.35) upstream to the Highway 900/ Renton-Issaquah Highway (RM 7.02), • Reach 6 -from the Highway 900 (RM 7 .02) upstream to the east end of the May Valley Subarea boundary along the North and South Forks of May Creek. Each of the reaches in the May Valley Subarea were delineated based on their unique geomorphic characteristics and reach-specific problems, as defined in the Action Plan (King County 2001 ), including: wetland, stream, and fish habitat condition and use, flooding, water quality, erosion, and s ediment deposition. File No . 1079 /-005-00 December 19, 2008 Page 15 GEOENGINU~ Reach 1. Subarea boundary (RM 3.9) to 14tf' Avenue SE bridge (RM 4.5) Malnstem Reach Description and Conditions Reach I is approximately 0.6 miles long, beginning at the May Valley Subarea boundary located at RM 3.9 and ending at the 1481h Avenue SE at RM 4.5 (Figure 6, Appendix A). This reach is transitional between the high-gradient canyon section of May Creek, downstream from Coal Creek Parkway, and the low- gradient main portion of May Valley upstream of 1481h A venue SE. The reach is a migratory corridor for anadromous salmonid species and provides some spawning and rearing habitat. Aquatic and riparian habitat in this reach has been impaired by erosion, channel incision, habitat simplification, and loss of large woody debris . May Creek in Reach 1 includes an incised channel such as this adjacent the Duffus property near RM 4 .0 . This section of May Creek has a mean annual flow of approximately 13.6 cfs (Conditions Report, King County 1995). In general, most flood events in Reach I , including the lOO-year flow event, are contained within the stream channel (Conditions Report, King County 1995). Channel conditions include the following: • From RM 3.9 upstream to a point just above the 143rd Avenue SE bridge, the May Creek channel is confined. The channel has a moderate gradient with instream and riparian habitat that has been degraded by erosion and headcutting. • From 143rd Avenue SE bridge (RM 4 .1) and 1461h Avenue SE bridge (RM 4.3) the streambed gradient decreases and the stream has greater access to the floodplain. There are no known significant flooding or erosion problems in this part of the reach, but aquatic habitat has been assessed as degraded in the Conditions Report (King County 1995) and Action Plan (King County 2001). • From the 1461h A venue SE bridge upstream to the 14gth A venue SE bridge crossing, May Creek transitions into a low-gradient stream with an undersi zed channel and wide floodplain. The undersized channel frequently floods into a wetland described in the Action Plan (King County 200 l) as degraded. • An ineffective flow segment exists from RM 4.3 to RM 4 .9. The Conditions Report (King County 1995) indicated that HEC-2 model results showed the bridges across May Creek at the Coal Creek Parkway, the 143n1 Avenue SE, and the 1461h Avenue SE roads as having sufficient elevation (capacity) to accommodate I 00-year floodwaters of both current (King County 1995) and future conditions. HEC-RAS modeling conducted by OTAK in 2006 and 2007 confirms those findings . File No. 1079 /-005-00 December /9, 2008 Page 16 G!OENGINl!U~ I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Tributaries and Conditions Two tributaries flow into May Creek within Reach 1. An unnamed tributary (# 0287D) flows into May Creek from the north (right) bank at RM 4.4, approximately 700 feet downstream from the 14gth Avenue SE bridge crossing. This tributary is approximately 0.4 miles long and contains fish passage barriers located at RM 0.08 (culvert) and 0.11 (pond spillway) respectively. The tributary tends to incise and scour vertically through sandy gravel alluvium overlying compact till or bedrock. The May Creek channel was observed to be unobstructed by silt or vegetation at the point of confluence with tributary # 287D , and appears capable of accommodating tributary inflow . There was some erosion in tributary # 287D, as the confluence area was largely devoid of vegetation due An unnamed tributary (# 287D) flows into May Creek to clearing and use as animal pasture . from the right (north) bank near RM 4.4 . The second tributary, Greene 's Creek (tributary # 288), enters May Creek from the south (left bank) near RM 4 .5, just downstream from the 1481h Avenue SE bridge crossing May Creek. This tributary has a mean annual flow of approximately 1.5 cfs and is expected to receive ever increasing flows due to de velopment (Conditions Report 1995). It is currently eroding through compact silty glacial outwash near th e confluence. The channel functions primarily as a stormwater drainage ditch, conveying water from recently built residential developments to the mainstem Creek. High stormwater flows are detained in a stonnwater pond of approximately I acre in area, located near the confluence with May Creek. Reed canarygrass (Phalaris arundinacea), willow (Salix spp.), and other riparian vegetation grow densely near the confluence of Greene 's Creek and May Creek , obscuring the confluence area . If planted and allowed to mature, riparian vegetation coupled with the placement of large woody debris may stabilize the channel, but increased flows are anticipated to continue to carry sediment (sand/silt) to May Creek. Fish Dis tributi o n and Ha b itat Use This reach has the highest anadromous salmonid species use of all the May Creek reaches in the Valley. The upstream limit of distribution for such species as sockeye (Oncorhynchus nerka), steelhead (0. mykiss) and Chinook salmon (0. tshawytscha) is either within or below this reach (RM 4 .5). The reach is primarily a migratory corridor for coho salmon and cutthroat trout. These species are able to move upstream to spawn and rear in reaches of May Creek and tributaries, as described later in this document. The aquatic, riparian and wetland habitat in Reach l has been degraded as a result of landuse management inc lude historic logging and mining activities, and more recent animal pasture activities. File No . I 0 79 1-005-0 0 December 19, 2008 Page 17 GEOENGINHM~ Reach 2. 14tf' Avenue SE (RM 4.5) to Colasurdo/Fisher boundary line (RM 5.35) Reach Description and Conditions Reach 2 is approximately 0.85 miles in length, extending from the 1481h Avenue SE bridge crossing to a point near the Colasurdo (Celigoy-Norton) and Fischer property boundary line (Figure 7, Appendix A). Reach 2 has mean annual flow of approximately 8.6 cfs (Conditions Report, King County 1995), with a gradient of less than I percent throughout its length. This reach is characterized by a single, undersized channel that has been artificially straightened and dredged. The adjacent floodplain is a degrade d wetland used presently and historically as pasture and for other agricultural purposes (Conditions Report, King County 1995). Reach 2 of May Creek , at a flow of 12 cfs, looking downstream during the February 2007 site visit. NntA flnorl inn nf n;:1st1 irA nn rinht Anrl IAft hAnks The Conditions Re port (King County 1995) and the Action Plan (King County 200 1) characterize Reach 2 as being subject to numerous problems, including frequent flooding, sedimentation, degraded water quality, degraded wetland habitat, and degrading riparian and aquatic habitat. ln many areas the channel has been further constricted by sedimentation and the invasion of reed canarygrass. Overto pping of th e banks occurs at relatively low flows (e.g. 12 cfs during February site visit), and floodwaters can remain on the floodplain for months at a time. Most sediment entering this reach is either deposited on the floodplain immediately adjacent the channel or in the channel due to in effective (low) flow conditions. An ineffective flow segment exists from RM 5.05 to RM 5.3. Tributaries and Conditions A number of small tributaries flow into May Creek in Reach 2. Two tributaries are described in the Conditions Report (King County 1995). Long Marsh Creek (Tributary #289) and Indian Meadow Creek (Tributary #29 1) both flow into May Creek from the north (right) bank and convey storm water runoff from the Highlands Subarea. As compared to other tributaries in the adjacent subareas, these tributaries drain a di s proportionately high volume of water to May Valley. Higher rainfall and steeper terrain contribute to the high flows and sediment loads, in spite of the relatively dense forest canopy cover. These tributaries produce high levels of sediment, exacerbate flooding, and degrade channel functions and habitat in Reac h 2 (King County 1995). The Conditions Re port (King County I 995) descri bed Long Marsh Creek as having a mean annual flow o f approximately l.8 cfs, e ntering May Creek ne ar RM 4 .6. The gradient of Long Marsh Creek is moderate (less than 5 percent) within the lowermost 0 .2 mil e. The streambed gradient increases to approximately 10 percent up to RM 0.25, and then decreases upstre am of RM 0.25. The lower 0 .2 miles of Long Marsh Creek flows across an alluvial fan that rests on g lacial till. This section of channel has incised through the alluvium, has File No . 10791-005-00 December 19, 2008 Page 18 The confluence of May Creek and Indian Meadow Creek (Tributary #291) is clogg ed with silt and reed canaryg rass . GeoENGINHA~ I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I been dredged and straightened, and has little riparian vegetation . These changes in gradient and geology have intensified erosion in Long Marsh Creek and sediment deposition near the conflu ence with May Creek. Culverts, a waterfall, a dam and other barriers are located in the Creek at or below RM 0.3. The Conditions Report (King County 1995) d escribes Indian Meadow Creek as having a mean annual flow less than 5 cfs. The point of confluence is loc ated on May Creek at approximately RM 4 .85 . T h e gradient of Indian Meadow Creek is low (less than 1 percent) within the lowermost 50 feet where it has b een diverted to a subsurface c ul vert. The lo wermost 50 feet of Indi an Meadow Creek and the confluence area with the mainstem have been degraded by sed imentation and a proliferation of reed canarygrass . No discemable channel connecting Indian Meadow Creek to May Creek was observed during a recent site visit. The downstream end of the [ndian Meadow Creek culvert is a lmost comp le tely clogged by sediment and reed canarygrass, causing water to emerge from the culvert as sheet flow into May Creek. Fish Distribution and Habitat Use Reach 2 has limited aquatic habi tat and fis h use. Aquatic habitat has been degraded by dredging and by the use of the riparian corridor for grazi ng and other human uses . Coho salmon and cutthroat trout have historically used Reach 2 for rearing purposes and were captured by sportfishers. More recently, th is reach serves as a migratory corridor to upstream Locally Significant Resource A reas in the ?.9 1-A and Country- Cabbage Creek drainages. The Conditi ons Report (King County 1995) identified Couo salmon stocking as occurring between 148 1h A venue SE bridges and 164 1h A venue SE bridges, but did not specify a location. Reach 3 Colasurdo-Fisher Fence Line (RM 5.35) to 164 1h Avenue SE (RM 5.93) Reach Description and Conditions Reach 3 extends approximately 0.58 miles upstream from the Colasurdo (Celigoy-Norton)-Fischer fence line, to the 1641 h Avenue SE bridge (Figure 8, Appendix A). This reach is characterized by a very low gradient, a wide floodplain , and an abundance of hydrophilic vegetation (e.g. reed canarygrass,). The creek flows through a degraded wet land with several fish passage impediments caused by channel constrict ions and sedimentation . Reac h 3 has an ill-defi ned or non -existent channel throughout most of its length. Where a defined channel does ex ist, th e adjacent streambank is typica ll y saturated , posing a risk of further erosion a nd sedimentation of the main channel. The history of dredging in May Creek is evidenced throughout this reach by the unnaturall y straight channel a li gnment. The creek is undersized throughout this reach. Excessive sediment and riparian vegetation exacerbates th e degraded channe l condition and frequency of flooding. This area of the May Valley is rural in character, with a mix of residences, open space and pasture land for stock. An ineffecti ve flow segment exists from RM 5.48 to RM 6.53. File No. /079/-005-00 December 19, 2008 Page 19 Reach 3 of May Creek contai ns secti ons comp letely clogged with reed canaryg rass and silt. GEOENGINU~ The Conditions Report (King County 1995) and Action Plan (King County 2001) assesses frequent flooding, habitat degradation, and water quality problems as prevalent within Reach 3. Tributaries and Conditions One notable tributary is present in Reach 3, tributary #291A, which flows into May Creek from the left (south) bank. The Action Plan (King County 2001) identifies this tributary as a "Locally Significant Resource Area" (LSRA), given its use by cutthroat trout (0. clarki) and coho salmon (0. kisutch). This Tributary has a mean annual flow of approximately 1.6 cfs. In the vicinity of the tributary/mainstem confluence, both channels are currently subject to extensive deposition and dense growth of hydrophilic vegetation. At the time of our site visit, the lowermost 300 feet tributary channel was very poorly defined, and the main stem channel appeared to be significantly aggradcd. The Conditions Report (King County 1995) describes the confluence area as being located at RM 5.5 on May Creek. During the July 2007 site visit the channel was found to be dry within the lower reaches. Tributary 291A was found to be intermittent during the July 2007 site visit. The headwaters of Tributary 291A include two wetlands (Wetland 2 and 3, King County 1995). The two wetlands have been described as degraded by residential development. Wetland functions are expected to further degrade as development in this area expands . Historically, these wetlands moderated flood ing, improved water quality, and provided aquatic, wetland, and riparian habitat in Tributary 291A and May Creek. The Conditions Report (King County 1995) describes this tributary as highly unstable, with further degradation likely to occur as landscape modifications continue in the uplands areas. Tributary 291A is expected to continue to erode, providing a continuous source of sediment to May Creek. This ongoing process is further destabilizing the channel, increasing the risk of flooding, and degrading habitat in the confluence area. The Conditions Report (King County 1995) states that "[w]itbout mitigation for the past increases in flows and sediment transport and without any significant stream bank vegetation and LWD, the channel will continue to incise and erode, delivering increased sand downstream. Increased flow and sediment transport will increase sand delivery into May Creek." Fish Distribution and Habitat Use Anadromous salmonids use Reach 3 primarily as a migratory corridor to access Tributary 291 A and the Country-Cabbage Creek drainage (tributaries in Reach 5). Based on field observations, anadromous fish migration has been severely impaired by the loss of a defined channel within Reach 3. Coho sa lmon have previously been stocked between the 148 1h Avenue SE (lower Reach 2) and 164111 Avenue SE (upper Reach 3) bridges. According to the Conditions Report (King County 1995) returns h ave been very limited . Tributary 291A is identified in the Action Plan (2001) as a Locally Significant Resource Area (LSRA). This tributary has been used by both cutthroat trout (0. clarki) and Coho salmon (0. kisutch), with observation of cutthroat and coho spawning in the tributary up to RM 0.3. The Conditions Report (King County 1995) states that in 1994 cutthroat trout were found rearing in Tributary 291 A up to RM 0 .5 (location of perched culvert). File No . 10791-005-00 December /9, 2008 Page20 GIOENGINHRS~ I I I ' I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Aquatic habitat u se has been impaired by aggradation of channe l near the confluence area and by erosion in Tributary 291 A between RM 0.1 and 0.3 (Conditions Report, Kin g County 1995). Upstream portions of Tributary 291 A have been ditched and placed in culverts, further reducing aquatic habitat value, and intensifying erosive forces and runoff rates below the culverts. Reach 4. 164th Avenue SE (RM 5.93) to Hendrix Creek Confluence Area (RM 6.35) Reach Description and Conditions Reach 4 extends approximately 0.42 river miles from the 1641h Avenue SE Bridge (RM 5 .93) up stream to approximately RM 6.35 near the confluence of May Creek and Hendrix Creek (Figure 9, Appendix A). Like Reaches 2 and 3, this reach includes a low-gradient c hannel, wide floodplain , and an abundance of hydrophili c vegetati on ( e.g. reed canarygrass, P . aru ndinaceae) throughout the flat vall ey topography. The hi story of dredging in May Creek is apparent, as evidenced by the straight channe l a li gnment. Mos t of this reach has a single, we ll defined, and undersized c h an n e l extending throug h a degraded wetland and broad valley floodplain. Excessive sediment and riparian vegetation extending into the channel exacerbates the degraded channel condition. This area of the May Valley is primarily rural, mixed with limjted commercial and residential development, open space and pasture land for live stock. Reach 4 of May Creek contains sections of ineffective flow such as this section above the 1641h Avenue SE Bridge. This reach is subject to flooding, sedimentation and water quality problems, as well as degraded wetland, riparian and aquatic habitat. Approximately 5.6 square miles of the May Creek basin, o r 40 percent of the total basin, drains into R each 4 (King County 1995). The CondHions Report (King County 1995) identifies the 164111 Avenue SE Bridge crossing as having insufficient capacity to pass flood flows and indicates that the 25-year flow would overtop the bridge and cause roadway flooding . As development conti nues in the headwaters of the May Creek basin, flooding, erosion, sedimentation, and habitat degradation is expected to worsen in Reach 4. An ineffective flow segmen t exists from RM 5.48 to RM 6.53. Tributaries and Conditions There are two tributaries to May C reek in this reach, identified on maps and the GIS database as unnamed tributary (029 l-B) and Hendrix Creek (Tributary 029 1-C). Tributary 0291-B is a small stream with a mean annual flow of less than 5 cfs (Kin g County 1995). It enters the vall ey from th e south (left bank), with its confluence is located immediately ups tream from the 1641h Avenue SE bridge crossing (RM 5.93). No well defined confluence of tributary # 291-B a nd May C reek and no well defined channel within the lowermost I 00 feet was observed during recent site v is its. Tributary # 291-B serves primarily as a s tormwater drainage ditch, conveying water from the East Renton plateau south of the May Valley. In the upper portion of the creek, the tributary has been c hanneli zed to form drainage ditches and placed in culverts along much of its length, including that portion near the semi-commercia l intersection of 1641h Avenue SE and SR 900. File No. /079/-005-00 December /9, 2008 Page 2 1 Tributary 291B upstream from the May Creek con fl uence has been converted to a storm drain for 1641h Avenue SE. GEOENGINl!HS~ Hendrix Creek (Tributary # 29 1-C) enters May Creek from the south (left bank). Again, there is no well defined confluence area between Tributary 291 B and May Creek, and no well defined Tributary channel within the lowermost 100 feet of the May Valley floodplain. Tributary 2918 serves as a stormwater drain, moving water from the East Renton plateau south of the May Valley. The tributary has a mean annual flow less than 5 cfs (Conditions Report, King County 1995 ). The Conditions Report (Ki ng County 1995) and Action Plan (King County 2001) describes the upstream portions of the creek as channelized and placed in culverts, including that portion intersecting SR 900. Fish Distribution and Habitat Use Anadromous salmonids use Reach 4 primarily as a migratory corridor to access upper May Creek and certain tributaries like the Country-Cabbage Creek drainage upstream in Reach 5. Salmonid migration has been severely impaired by channelization, loss of wetland function, and loss of riparian and aquatic habitat. Tributaries 291 Band Hendrix Creek are small, disconnected streams with no known anadromous fish use. Reach 5. Hendrix Creek Confluence Area (RM 6.35) to SR-900 Bridge (RM 7.02) Reach Description and Conditions Reach 5 includes approximately 0.67 river miles of May Creek extending from the Hendrix Creek confluence area (RM 6.35) upstream to the SR-900 bridge crossing (RM 7.02), see Figure IO (Appendix A). Reach 5 includes the upper-most portion of the broad, low-relief, portion of the May Valley floodplain. This reach of May Creek, like Reaches 2, 3, and 4, flows in an artificially straightened channel through a degraded wetland. This section of the May Valley is used as pasture, hobby-farming, and residential purposes. Unlike other reaches within May Valley, Reach 5 contains relatively diverse stream habitat, along with varied substrate composition and some healthy riparian areas. The reach is characterized by a wide, low gradient (less than I percent) channel with a slightly more sinuous channel morphology than the other four downstream reaches. It has a relatively high level of floodplain connectivity. Based on channel form, bend configuration, distribution of sediment deposits, and the character of erosion, the channel appears to be subject to active channel migration. Reach 5 of May Creek contains some of the last remaining viable salmonid spawning habitat along the mainstem in May Valley. The upper-most portion of this reach is free-flowing, and bisects a forested wetland that is in an early succession stage. This forested wetland is thought to exhibit the type of wetland, riparian and aquatic habitat present in the May Valley prior to anthropogenic disturbance. This wetland, however, has not fully matured to include coniferous species like western red cedar, Sitka Spruce, and western hemlo ck likely present prior to logging in the valley, as described in the Conditions Report (King County 1995). An ineffective flow segment exists from RM 6.95 to RM 7.3. The channel through this reach is expected to continue to migrate and braid. Future migration rates will depend on rates of incoming sediment influx, as well as changes in peak flows, the extent of local bank File No . 10791-005-00 December 19, 2008 Page22 GeoENGtNtH.s_uil I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I hardening, and influence of backwater conditions associated with the bridge. It is also possible that channel position and/or alignment could change abruptly in the course of a single large flow event or a series of smaller events. Any such change may have a profound effect on the alignment and character of one or more downstream reaches . T ri b utaries and Conditi ons One tributary is present within Reach 5. This tributary, however, conveys flow from two individual creeks, Country Creek (Tributary 292) and Cabbage Creek (Tributary 293). The Country Creek and Cabbage Creek drainages flow in a southerly direction, draining the Highland area north of the May Valley. Like other tributaries draining the Highland Subarea, the creeks produce relative ly high flows per unit area. Both creeks have been placed in culverts under the SE May Valley Road on the north side of the valley . Upon reaching the valley floor, the creeks have been re-directed to flow in a westerly direction, joining together to form lower Country Creek. Erosion and flooding are common problems where the channels have been re-a ligned, and placed in improperly designed, poorly installed or poorly maintained culverts. Country Creek has a mean annual flow of approximately 1.3 cfs. Lower Country Creek flows approximately 0 .2 miles across the May Valley floodplain to a point of confluence with May Creek at RM 6 .5. Country Creek is identified in the Conditions Report (1995) as stable, with little risk of significant change in flooding or sedimentation. The Country-Cabbage Creek drainage is a Locally Significant Resource Area (LSRA) due to the valuable salmonid habitat. Cabbage Creek has a mean annual flow of approximately 1.9 cfs. The Cabbage Creek drainage, however, as identified in the Conditions Report (1995) as unstable and subject to increased flooding, erosion, and sediment delivery to lower Country Creek and May Creek as development continues in the Highlands area. Cabbage Creek contributes the highest runoff of all the tributaries to the May Creek Basin. Fis h Distribution and Ha bit at Use Lower Country Creek between RM O and RM 0.11 was identified in the Conditions Report (King County 1995) and the Action Plan (King County 2001) as a Locally Significant Resource Area (LSRA) because this section of tributary stream is used by Coho salmon (0. kisutch) and cutthroat trout (0. clarki) for spawning and rearing purposes . This tributary has degraded habitat due to channel straightening, loss of instream habitat complexity, Joss of large woody debris, and loss of riparian cover and functions. The Conditions Report (King County 1995) describes upstream passage into Country and Cabbage Creeks as blocked above RM 0.11 by a concrete block. The remaining habitat, however, provides some of the last remaining, productive habitat in the May Valley. File No. I 079 1-005-00 Dece mber /9, 2008 Page 23 G!OENGINf.EASg Reach 6. SR -90 0 Bridge Crossing (RM 7.02) to Upper May Valley Subarea Boundary Reach Description and Conditions Reach 6 is the upstream-most reach within the May Valley Subarea, and provides a transition between the low-gradient May Valley a nd moderate-gradient headwater tributary strea ms. The North, East, and South Forks of May Creek (headwater tributaries) compose the majority of Reach 6 including approximately 0. 75 miles of the North Fork (Tributary 294A), 0.6 miles of the East Fork {Tributary 297), and 0.56 miles of the South Fork (Tributary 282) of May Creek. These three tributaries join together in thi s transition reach to form the main stem May Creek, less than 0.1 mile from the SR-900 bridge crossing (Figure 11, Appendix A). The mainstem May Creek in Reach 6 has primarily been affected by construction of SR-900. This portion of May Creek has been directed through an arched culvert (see photograph), under the highway . Fill was placed on either side of May Creek to form the road prism. Embankments and arch culvert wingwalls further confine the channel , conveying water from Reach 6 into upper Reach 5. The mainstem May Creek, however, comprises less than 0.1 mile of Reach 6. An ineffective flow segment exists from RM 6.95 to RM 7.3. Tributaries a nd Conditio ns Reach 6 of May Creek extends upstream from this culvert under SR-900, including portions of the North , East, and South Forks of May Creek . The North Fork May Creek between RM O and 0 .7 ha s been moved and straightened from its origi nal position (Condition Report, King County 1995). Historically, this channel was thought to be a moderate to low-gradient channel meandering through a cedar, cottonwood, and alder forest. The East Fork May Creek flows into the South Fork May Creek within a forested wetland. The tributary has a low gradient up to RM 0.45, with a steeper gradient between RM 0 .45 and 0.6 where it crosses an alluvial fan. On the alluvial fan, the channel flows through a culvert under the SE May Vall ey Rd , which forms the eastern boundary of this portion of the Subarea. The South Fork May Creek flows approximately 0 .56 miles in a northweste rl y direction. The cha nnel has a low-gradient through the lower portion of thi s reach up to RM 0 .3 (May Creek RM 7.3), flowing adjacent to a sand and gravel mining operation. Upstream from RM 0.3 the gradient increases to approximately 10 to 15 percent with a substrate of sand and gravel. Between RM 0.3 and 0 .6 the South Fork of May Creek travels through an area that has recently experienced residential development. As development increases in the headwaters of May Creek, flooding and erosion are expected to worsen in the North, East, and South Fork of May Creek. Severe future erosion problems have been predicted for the North, East, and South Forks of May Creek (Conditions Report, King County 1995). Increased flood flows and sedimentation conveyed from the headwaters are anticipated to further degrade the mainstem May Creek in the May Valley, causing further flooding, sedimentation, and habitat degradation . Fish Distribution and Habitat Use The North, East and South Forks of May Creek have been severely impacted by SR-900, culverts, berms and quarries . However, Coho salmon (0. kisutch) and possibly cutthroat trout have been observed in the North and East forks of May Creek. WDFW has planted coho in the upper North Fork between RM 1.0 and 1.45 . No fish use has been reported in the South Fork. File No. /079/-005-00 Decem ber 19, 2008 Page24 G!OENGINHM.0 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I RESTORATION CONCEPTS The project design team offers the following summary of approaches that have been used to address flooding, ineffective flow, sedimentation and habitat degradation in other rivers, creeks and streams. In this section, restoration concepts are described generally. Subsequent sections of this report look at feasibility of restoration concepts given the existing and desired future condition in the May Creek drainage basin, and suggest a prioritized approach to conceptual project implementation. Restoration actions represent modifications to the stream channel, banks, floodplain, and/or drainage basin intended to restore self-sustaining channel form and function to an otherwise degraded channel. Potential restoration actions include direct, indirect, and off-channel modifications. Restoration actions described in this CRP focus on actions to reduce flooding, protect and restore aquatic habitat for anadromous species, while also addressing issues identified in Recommendation #5 in the Action Plan (King County 200 I). Actions are generally categorized as either direct channel modifications, indirect channel modifications, or off-channel modifications. DIRECT CHANNEL MODIFICATION Direct channel modification involves reconstruction of the channel by altering the channel cross-sectional area, planform, and/or profile. Directly modifying channel shape and geometry can alter the channel's water conveyance to serve restoration needs. • Cross-Section Modification: The cross-sectional area of a channel is defined by its overall depth and width. Typically, reducing the cross-sectional area of a channel will decrease channel capacity while increasing water velocity. The opposite is true for increasing the cross-sectional area of a channel. Cross-section modification can be used to increase or decrease sediment transport capacity, alter flood stage elevation, bank erosion, and habitat. • Planform Modification: Channel planform is defined as the shape and sinuosity of a channel as seen from above. Modifying channel planfonn will serve to lengthen or shorten the channel, thereby altering channel gradient, water velocity, and sediment transport capacity. Channel planform can also be modified by altering the connectivity of the primary channel with the floodplain and associated abandoned channels (i.e.: levee modification and/or removal). Reconnection with the floodplain can reduce water velocity, flooding downstream, and alter sedimentation. o Profile Modification: Channel profile is defined as the variation in elevation of a channel over its length (i.e.: gradient). The profile of a stream channel may be altered as a means of controlling energy dissipation patterns within the channel. Altering energy dissipation along a channel serves to vary water velocity and therefore stream power and sediment transport capacity, promoting channel complexity. Measures taken to change a channel's profile may include lengthening of the channel by increasing sinuosity, installing drop structures, or increasing bed roughness with large woody debris or boulders. INDIRECT CHANNEL MODIFICATION Indirect channel modification incorporates incremental changes in channel-forming processes, wherein the introduction of a feature or structure induces channel change over time. Features or structures may include: In-stream structures, Bank Structures, In-stream nutrients and substrate management. Promoting certain channel-forming processes in strategic locations can be used to modify water conveyance through the channel to serve restoration needs. File No. /0791-005-00 Decemher 19, 2008 Page 15 GEOENGINEEIIS _g In-stream Structures The placement of in-stream structures is primarily used to redirect flow, control channel grade, and/or increase channel complexity and fish habitat. Following are several examples of in-stream structures and their uses: o Boulder clusters: The placement of large, immobile boulders in a homogeneous stream section is used to increase channel complexity by increasing the hydraulic diversity and structural composition of the channel. Immobile boulders create water velocity gradients (fast-moving water adjacent to slow-moving water) desirable to many fish species. Boulder clusters represent channel roughness elements and may promote localized scour and may induce a backwater effect upstream. o Drop Structures: Drop structures are low-elevation structures spanning the width of the channel creating an abrupt drop in channel bed and water surface elevation redistributing and dissipating energy. Grade controls, sills, and weirs are examples of drop structures primarily used to regulate channel grade and to increase channel complexity. Drop structures are used to stabilize the channel bed, limit incision, promote the collection, sorting, and deposition of sediment, and improve fish habitat. 0 Beaver Management: Beaver dams are excellent sediment traps that can greatly reduce downstream sediment loads. In certain systems, beaver dam drop structures can be utilized in a restoration plan. Beaver dams typically impound water, reduce water velocity and bank erosion, improve fish habitat, and elevate the water table upstream of the dam. • Fish Passage: In-stream structures including culverts, woody debris, weirs, and other drop structures may be barriers to fish passage if not properly configured to the associated channel and flow regime. The "fish passage" action includes that action that removes or modifies structures to allow fish passage to upstream reaches. Removing or modifying in-stream structures may also impact stream character, potentially increasing channel conveyance, sediment transport capacity, and water velocity. The timing, frequency and duration required for unimpeded access varies by fish species, therefore target fish species should be identified before fish passage barriers are modified. o Large Woody Debris (LWD) and Log Jams: Large wood can provide both structure and habitat to a stream. Woody debris and logjams can alter the channel pattern and planforrn and promote scour. Woody debris is also a roughness element in streams increasing friction, reducing water velocities, retaining and sorting sediment, and recruiting organic debris and nutrients. For these reasons, woody debris is often used to stabilize banks and provide fish habitat. o Porous Weirs (U-shaped, V-shaped, and J-hook): A porous weir is primarily used to redirect flow and increase channel complexity. Most porous weirs are constructed of boulders and may incorporate pieces of LWD. Water is redirected as it passes partially through and over a porous weir, unlike traditional weirs where water flows entirely over the top. The shape of the porous weir dictates its use in a stream, because water flows over and through a porous weir perpendicular to the weir's face. As such, U-shaped and V-shaped weirs generally point upstream and span the width of a stream directing flow to a pocket in the middle of the structure where scour typically occurs. J-hooked weirs are similar in shape and function to U-shaped and V-shaped weirs, but generally do not span the width of the channel. J-hookcd weirs are angled upstream with a "hook" focusing flow through a pocket. Scour occurs in the pocket of the hook and in some cases along the downstream length of the structure. J-hooked weirs are most commonly used to direct flow away from the bank and toward the center of the channel while U-shaped and V-shaped weirs are most commonly used to create channel complexity. File No. 10791-005-00 December 19, 2008 Page26 GeoENGINEER~ II I i . . I I I I I I I I I I I I I I I I I I I I • Bank Structures Bank structures used for restoration purposes generally encourage natural processes. L WO and rock are the most common materials used for bank structures in conjunction with riparian vegetation. Often the purpose of a bank structure is to stabilize bank soils in order to facilitate the establishment of riparian vegetation. Both LWD and rock can affectively dissipate stream power without dislodging from the bank, providing protection for bank soils and deflecting flow back toward the middle of the channel. In-Stream Nutrient and Substrate Management • Nutrient Management: Distributing fish carcasses, analogs (processed fish cakes) and fish fertilizer augments in-stream nutrient levels and improves fish habitat. Nutrients help fish health by increasing biologic activity, productivity in riparian zones and associated uplands, and food for juvenile fish and macro invertebrates. • Substrate Management: Adding and/or removing substrate materials to a stream encourages the natural redistribution and sorting of sediment enhancing fish and aquatic insect habitat. Spawning habitat is dictated, in part, by the size, permeability, and compaction of the substrate. Removing fines and/or adding gravel to a stream may therefore improve spawning habitat. Substrate management treats a symptom of a larger problem, and should therefore be used in conjunction with other restoration techniques in an effort to solve the larger problem. OFF-CHANNEL MODIFICATIONS Off-channel modifications include improvements to the floodplain and drainage basin that can benefit the restoration effort of the stream. Following is a list of several off-channel modification measures beneficial to stream restoration: • Riparian Area Protection and Restoration: The riparian area includes the active floodplain and adjacent plant communities. A well-established riparian area can provide shade, woody debris, organic material, and nutrients to the stream. Riparian soils and vegetation will retain water during storms. The vegetation will stabilize stream banks and provide near-bank fish cover and habitat as well as adding a roughness component to the floodplain and banks. Restoration of the riparian area may require years to decades to be realized and requires short and long tenn land use compliance. • Off-Channel Habitat Restoration: Off-channel riparian habitat depends on the connection with water and nutrients from the main channel distributed via surface flow or hyporheic (subsurface) flow. Allowing flood flows onto the floodplain and allowing hyporheic interaction in the riparian zone will benefit the off-channel and riparian habitat. • Modify the Amount of Erosion in the Drainage Basin: Often the root cause of a degraded stream is the lack or abundance of sediment available to the stream. Reducing large-scale inputs of sediment, meanwhile maintaining small-scale gravel recruitment areas, will promote a healthy substrate for spawning and reduce channel aggradation. Land use and land cover may need to be altered in order to achieve the desired volume of sediment available to the stream. • Land Acquisition: Land use is most often dictated by the owner of the land in question. Modifying land use to reflect the goals of the restoration effort is paramount to successful stream restoration. If favorable land use and/or restoration efforts cannot be realized with the current land owner, a land acquisition may be an option, provided that the necessary funds are available. File No. 10791-005-00 December /9, 2008 Page 27 GEOENGINEERS.i o Reduce Sediment Load: Aside from reducing erosion, sediment loads can be further managed by capturing sediment before and/or after it enters the stream. Dense vegetation can effectively capture sediment from surface sheet flow. Sediment detention basins are used to capture excessive sediment from stream flow. A sediment detention basin is an area where sediment-laden water is directed to a low-energy environment for a time period sufficient to allow fine sediment to deposit. Mechanical removal of sediment from the basin is often required. o Reduce Surface Runoff: Reducing surface runoff in a drainage basin will directly reduce flooding in the valley and may reduce in-stream erosion. Surface runoff can be reduced by reducing the area of hard (impermeable) surfaces in the basin, increasing vegetative cover, and increasing residence time on the slope. o Water Storage and Stormwater Retention: Increasing the amount of time required for surface runoff to reach the stream will reduce the peak flood discharge of the stream and may reduce erosion. Water storage and stormwater retention via ponds and/or infiltration act to meter flow into the stream, thereby reducing peak storm discharge by lengthening its duration. FEASIBILITY OF RESTORATION ACTIONS The feasibility or applicability of the various restoration actions described above was evaluated based on the regional, basin, reach, and site-specific characteristics of the May Creek basin. The feasibility of using potential restoration actions to address issues identified in the Action Plan, Recommendation 5 were also evaluated based on the scope of that Recommendation. Furthermore, the feasibility of using restoration actions to address May Valley issues were evaluated in terms of landowner interest, permitting, regulatory compliance and funding opportunities identified while scoping this report. The following summarizes the feasibility of the various potential restoration actions. DIRECT CHANNEL MODIFICATION o Cross-Section Modification was determined to be an unlikely or infeasible action in low-gradient sections in the May Valley (Reaches 2, 3, 4). The channel in the May Valley is already undersized in many areas. Invasion of non-native plant species like reed canarygrass has resulted where reduced channel capacity and reduced velocity exist. This may be a feasible approach in higher gradient reaches (Reaches 1, 5, 6) and/or tributaries (Long Marsh Creek, 291A, Country-Cabbage or other tributaries). o Planform Modification was determined to be an unlikely or infeasible action in the low-gradient sections of May Valley. Increased sinuosity may result in reduced stream power. Reduced stream power would likely result in increased sediment deposition and further clogging of undersized channels in these low-gradient reaches. Planform modifications may be feasible treatments in higher gradient areas like Reaches 1, 5, 6 or tributaries like Long Marsh Creek, 291A, Country-Cabbage or other tributaries. o Profile Modification was determined to be an unlikely or infeasible action given the very low- gradient of most of the Reaches in May Valley. Grade control structures or roughened channel profile modifications may be feasible treatments in higher gradient areas like Reach I or in tributaries like Long Marsh Creek, 29 lA, Country-Cabbage or other tributaries. FUe No. /079/-005-00 December I 9, 2008 Page28 G!OENGINEC~ I I I I I I I Ceil fill) I I I INDIRECT CHANNEL MODIFICATION In-stream Structures I I I I I I I I I I I I I I I I Generally instream structures were not deemed feasible restoration actions in the May Valley Subarea. lnstream structures would tend to reduce velocities and capture and trap sediments in the low-gradient areas of the May Valley. These structures would tend to increase siltation, flooding, and may accelerate erosion and channel migration. • Boulder clusters may be feasible actions in higher gradient areas like Reaches 1, 5, 6 or tributaries like Long Marsh Creek, 291A, Country-Cabbage or other tributaries. Concerns about head cutting, erosion, and loss of natural grade control structures in Reach I may feasibly be treated with boulder clusters. 0 0 0 0 Drop Structures generally are construed as infeasible restoration actions in the May Valley Subarea. However, a specialized beaver management drop structure may represent an effective restoration treatment in the valley. • Beaver Management may result in improved fish habitat while addressing flooding issues in the May Valley. It may be feasible to apply new methods like "Beaver Deceivers" that make use of naturally constructed drop structures (beaver dams) to increase habitat complexity while managing floodwaters and water elevations. Beaver Deceivers provide floodplain and fish habitat managers the ability to manipulate floodwaters and elevations while maintaining the natural habitat features of beaver dams. Fish Passage structures were generally deemed to be feasible restoration actions in the May Valley Subarea. Correction of impassible or partial passage barriers like constricted channels and improperly functioning bridges and culverts were deemed reasonable actions that could address both fish habitat and flood-related issues (such as backwatering effects) in the May Valley. Large Woody Debris (LWD) and Log Jams generally were not deemed feasible restoration actions in the May Valley Subarea. These instream structures typically reduce flow velocities and capture and trap sediments in the low-gradient areas of the May Valley. These structures would tend to cause increased siltation, and thus, flooding, and may accelerate erosion and channel migration. LWD and log jams may be feasible in higher gradient areas like Reaches I, 5, 6 or tributaries like Long Marsh Creek, 291A, Country-Cabbage or other tributaries. Porous Weirs (U-shaped, V-shaped, and J-hook) generally were not deemed feasible restoration actions in the May Valley subarea. These instream structures would also tend to reduce flow velocities and capture sediments in the low-gradient areas of the May Valley. Such structures would likely cause increased sedimentation, flooding due to aggradation, and may accelerate erosion and channel migration. LWD and log jams may be feasible in higher gradient areas like Reaches I, 5, 6 or tributaries like Long Marsh Creek, 291A, Country-Cabbage or other tributaries. Bank Structures In general, bank structures were determined to be generally infeasible for the low-gradient sections of May Creek in the valley, for the same reasons that instream LWD, drop structures, and porous weirs were deemed infeasible. Bank structures would, however, be feasible and may prove very valuable in addressing erosion, head-cutting and similar issues identified in higher gradient sections of May Creek ( e.g. Reach I) and in tributaries like Long Marsh Creek and the Country-Cabbage Creek drainage. File No. !0791-005-00 Decemher 19, 2008 Page 29 GEOENGINEEAS_g In-Stream Nutrient and Substrate Management In-stream nutrient and substrate management were deemed infeasible or inappropriate as potential restoration actions for the May Valley, given that they fail to address issues identified in Recommendation 5 of the Action Plan. o Nutrient Management was determined to be outside the scope of this project. Further, the May Valley tends to have an abundance of nutrients indicating that nutrient management would be unnecessary and potentially harmful to aquatic resources. o Substrate Management was determined to be an unlikely or infeasible restoration action. This restoration method would, at best, do little to address flooding. At worst, substrate management could worsen flooding problems in the low-gradient section of the May Valley. Substrate management, like boulder clusters and roughened channels may be appropriate for higher gradient areas like Reach I or tributaries like Longmarsh Creek or the Country-Cabbage Creek drainage. OFF-CHANNEL MODIFICATIONS o Riparian Area Protection and Restoration was determined to be a feasible and potentially a high priority treatment in the May Valley Subarea. o Off-Channel Habitat Restoration was determined to be a feasible restoration action in both low gradient and higher gradient sections of May Creek. Both riparian and associated wetland habitat protection and restoration actions were considered to be viable treatments. ij o Modify the Amount of Erosion in the Drainage Basin was generally deemed a feasible restoration action in the May Valley. Erosion and associated elevated sediment levels are significant problems in the basin. However, not all erosion reduction methods were determined to be feasible in such a low-gradient system. o Land Acquisition was determined to be infeasible because it is outside the scope of this project. The recommendations section of this report includes a brief discussion about how land acquisition may be a reasonable, feasible, and potentially a priority restoration action in the May Valley. o Reduce Sediment Load was determined to be a feasible restoration action in both low gradient and higher gradient sections of May Creek. Restoration and enhancement ofriparian and wetland habitat were determined to be potential treatments to reduce sediment. Stormwater and sediment basins were also considered to be potentially feasible treatments. o Reduce Surface Runoff was detennined to be generally infeasible. The ongoing conversion of forested uplands to residential areas and other project with impervious surfaces in the May Valley drainage basin will continue to increase surface runoff. The recommendations section of this report includes a discussion of potential, feasible actions outside the project area that may reduce or mitigate the effects of increased surface runoff. o Water Storage and Stormwater Retention was determined to be generally infeasible. Some feasible treatments such as stormwater ponds and wetlands may have minor storage components, but generally the volume of flood flows in May Valley far exceed the ability to reduce surface runoff within the project area (May Valley Subarea). The recommendations section of this report includes a discussion of potential action outside the project area that may be feasible treatments to reduce or mitigate the effects of increased surface runoff. File No. /079/-005-00 December 19. 2008 Page30 GEOENGINE!RSg u:J 111 ~ . ' I I I I I I I I I I I I I I I I I I Summary of Feasibility of Restoration Alternatives Restoration Alternative Treatment Name Feasibility in Low- Gradient Reaches (e.g. Reaches 2, 3, 4) Feasibility In Higher Gradient Reaches and Tributaries (e.g. Reaches 1, 5, 6, Longmarsh and Country-Cabbage Creeks) Direct Channel Modification ··--··---··---···---------·--··----- YES Channel Cross-Section Yes -ephemeral ------------------------------,~---~-----,-·------·-------------------- Planform Yes -ephemeral --------------------1-----'-----j YES YES Profile Yes -ephemeral ------------------------·---f----~-----j-------------··--·--------------- Indirect Channel Modification In-stream Structures No -unlikely YES ---------------------------·-+--------~----1---------------------------- Boulder Clusters No -unlikely YES 1---------------------·-·---------f------~---i------------·--·------·---·-·-····--···-··--·-···················--·-- Drop Structures No -unlikely YES ---------------1-------~---+----·----·--------------- Beaver Management YES YES l------~--------1----------,------------------····--··-· ····-··----·-·--·-- Fish Passage YES YES Large Woody Debris (LWD) __________ No -unlikely ·--t--------~----1 YES Porous Weirs No -unlikely ---·-·----------------!--------~--+------··---~-------------YES Bank Structures No -unlikely --------------------------------i--------------1 YES No-unlikely ------------1-------~----1 In-Stream Nutrient and Substrate YES Nutrient Management No -unlikely YES --------------·------·--·------"---------------!------~~--,---------------------·----·-·--·- Substrate Management No -unlikely YES ---------------!--------~---;- Off-Channel Modification ------------+------------!--------·----··----- Land Acquisition No -unlikely YES --·-1-------'---l·---------·-·------------------- Modify the Amount of Erosion YES YES ------·-+------------!-------------·---- Off-Channel Habitat Restoration YES YES Reduce Sediment Load YES YES •----------------+----------+-····-·-·-·-·-··-····-· Reduce Surface Runoff No -unlikely YES f---------------------------·---------,-----------1-----------------·-----·-----· Riparian Area Protection/Restoration YES YES Water Storage and Stormwater Retention No -unlikely No -unlikely RESTORATION ACTIONS AND PRIORITIZATION DEVELOPMENT OF RESTORATION ACTIONS The design team of MPSFEG, Geo Engineers, and OTAK staff used infonnation contained in the Conditions Report (King County 1995), Action Plan (King County 2001), GIS and LiDAR databases, HSPF and HEC-2 and HEC-RAS models, air photographs and other available infonnation to develop conceptual restoration projects. Conceptual project designs were developed to address reach-specific issues summarized in the reach descriptions provided earlier in this document. Conceptual project designs were also guided by the project feasibility principles summarized above. A total of 33 conceptual project designs were developed for the May Valley Subarea {Appendix C). Conceptual project designs were further developed and refined during site visits in 2006 and 2007. The efficacy of conceptual designs addressing biologic, hydrologic and hydraulic objectives described in Recommendation 5 in the Action Plan (King County 200 l) were evaluated by a variety of means, including hydrologic and hydraulic models. File No. }079/-005-00 December /9, 2008 Page 31 GeoENGINEEAS_g A project prioritization matrix was developed to assist the MPSFEG, King County, landowners, other others to select priority projects from among the 33 described. The following summarizes the prioritization criteria, process, and results. Please note that conceptual projects are preliminary and may be modified by the MPSFEG, King County, landowners or others to better meet project objectives. Please also note that the prioritization criteria, process, and results listed below are offered as a means to select and proceed with a preferred alternative project. The MPSFEG, King County, and May Valley landowners are encouraged to suggest changes to the prioritization criteria and process to better address project objectives, as described in Recommendation 5 of the Action Plan (King County 2001). PRIORITIZATION CRITERIA AND PROCESS GeoEngineers used a prioritization process consistent with the process used in developing recommendations in the Action Plan (King County 200 I). This approach enables project proponents and sponsors to compare the relative priority of projects in this Conceptual Restoration Plan with the priority of other projects identified in the Action Plan. The prioritization process applies five (5) general criteria to potential projects. More than two-thirds of the possible points in this prioritization methodology are contained in two major criteria: the importance of the problem addressed, and the overall effectiveness of the proposed project in addressing that problem. • Importance -(I to 10 scale): How important is the problem addressed by the project? Determining I I the significance of the problem is generally guided by the Solutions Analysis and information 1· presented in the Conditions Report. • Effectiveness -(I to 6 scale): How effective is the project as a solution to the problem? The detennination of effectiveness can be affected by the size and complexity of the problem; a well conceived project can receive a low Effectiveness score if it addresses only one aspect of a, complex problem. A little less than one-third of the possible points in this methodology are contained in three minor criteria that cover less critical, but still important aspects of the project. • Feasibility -(I to 3 scale): How hard will it be to undertake and complete the project effectively? This criterion accounts for the ease or difficulty of meeting permitting requirements. o Offsite/Multiple Benefits -(-3 to +3 scale): What effect(s) -positive and/or negative -will this project have on surrounding areas and the system as a whole? • Public/Local Support -(-1 to +I): If the community is aware of this project, has the response been positive or negative? I I I I I The maximum point total a project can receive using this methodology is 23 points. The following table provides a list of the projects shown in the order of their priority for implementation, as determined on a I basinwide basis using the above described prioritization process. File No. 1079/-005-00 December 19, 2008 Page32 GEOENGINEE~ I I I I I I •• I I I I I I I I I I I I I I I I Proposed Project Sequence1 A A B B C D E E F F F G G H H H H H H I J K K K K L L L L L M N N Notes: Prioritized List of Conceptual Restoration Projects Project Number Conceptual Project Name Reach Estimated Construction Cost2 7 1481h Avenue SE Culvert and High-flow Channel 1 and 2 $243,500 17 Beaver Management Demonstrati_on _ProjE3ct ______________ ----~·------__ $ ___ 1s_,_2_0_0_ 1 $ 160,200 -------·-··----·----·-··-·---·------·------------~---+-~----- $ 356,900 ----~--· 1641 h Avenue SE Conveyance Project IFP-3 __ lneffective__Flow Project3 __ _ 3 and 4 3 and 4 -------------------------------····-·-····-··-····-····-· ..... --------------4-------1 __ __4 ____ Hydraulic Control and High-flow Channel 15 May Creek Side-Channel Project $ 43,500 1 ________________ ,_ ________________ , ___________ ------ 3 $ 85,100 11 _________________ Colasurdo Wetland Enhancement -Reed Canarygrass Abatement ______ _? _______ $ __ a __ s_._20_0 __ 1 1 and 2 $179,700 --------·-·---+------! __ IFP:.!.__ Ineffective Flow_Project 1 _____________________________ _ 5 Stonegate Wetland Enhancement -Reed Canarygrass Abatement $ 69,000 6 _C3reene'sCreek(;onflu~_nc~l\reaP!oje_ct__ ___ __________ ________________ _ ________ !._ _____ 1_~$_5~9-,8~0~0~ IFP-2 Ineffective Flow Project 2 2 $ 58,200 ------+-~------1 ___ _1_1l_ _______ Tsegay WeUand Enhancement -Reed Canarygrass Abatement _____________ 2 ____ _, __ $~1_0_4_,s~o_o __ ______ _3~--_ Wetland Habitat Enhancement_(WSDOT South) _______________ !i ______ 1 _~$_6_B_.4_0_0~-, 1 Stream bank Protect and In stream Habitat Enhancement $ 190,100 -----------------------------1--~------------- 2 143rd Avenue SE Bridge Cro_ssi~g-----------·-------·-------·-----------·· 1 $ 148,500 16 _________ 29_1:ll_c:_~11~uence Area Proje~~-----------_ __ ______ 3 -5 --$ 160,200 $ 63,200 25 Cabbage Creek Culvert Replacement -------------- 26 ______ _ Country Creek Culvert_ Replacement 5 $ 160,200 27 _______ country-Cabbage Confluence Culvert Replacement ______________________________________ ?_ ____ ~-~$~1~6~0~,2,_0~0~- 24 Lower Country Creek Habitat Enhancement __ -----------------------______ ? __________ $_7_4_,_60_0_--1 2 __ , __ $_1_s_s_. 1_00 __ 2 $ 69,900 -·--·----------4-------l 14 Colasurdo Stormwater Detention Pond 1--------- ·······--···---~----·---· _ Long Marsh Creek Enhancement_ $ 33,900 ---·-··-·-···-----·--------.. ----·----·---------·----4--------__ g_ ______ . Indian Meadow Confluence Area Project 2 $ 362,000 --------···--·----·· --------! ....... ~--_Hendrix Creek Confluence Area_Projec~----------·--------·--·-·.,--.. 4 22 North Hendrix Wetland Complex 4 $ 172.800 3 Streambank and Off-Channel Habitat Enhancement $ 145,700 -----------------------·----·-·--·----------------·---------------------,------, ------~-~----·----_ 291-B Confluence Area Project 20 Stormwater/Sediment Retention Area ______ 2_~----North Fork High Flow Detention Basins 4 $ 61,600 -------------------------------·;;·---4 --$-1-1-9,400 6 $345,900 IFP--4 Ineffective Flow Project 4 6 $ 186,900 23 Coho Rearing Pond_______________________ _ _________________________________ !i ______ , __ $_27_,_3o_o_-J ---------~-------_ Dunvegan Trust Wetland Enhancement -ReedGanarygrass Abatement ______ 3 _____ 4 __ $_1_4_B_,3_o_o __ 13 Colasurdo Off-Channel Pond/Wetland Enhancement 2 $ 15,400 1 ~Proposed Project Sequence" -The alphabetical sorting of projects provideS a proposed sequencing of conceptual restoration action based on an application of the prioritization criteria and process described on page 30 of this report. 2 "Estimated Construction Cost" -This column provides planning-level cost estimates based on a uniformly applied construction cost estimation procedure. Nominal estimates of engineering design and permitting costs were included in the estimate as a small percentage of estimated construction costs. Actual costs may be significantly greater for projects requiring detailed engineering designs or complicated permitting or regulatory compliance actions. The actual percent cost of engineering or permitting/regulatory compliance may vary from project to project. File No. 10791-005-00 December /9, 2008 Page 33 GeoENGINEERS.i RECOMMENDATIONS This section of the CRP provides an initial sort list of prioritized projects that address issues identified in Recommendation 5 of the Action Plan (King County 200 I). Projects were developed in an effort to identify sustainable approaches to floodwater conveyance and habitat restoration that, once implemented, would be self-maintaining through natural channel-forming processes. The projects were developed on a reach-by- reach basis, progressing through the May Valley Subarea from a downstream to upstream orientation. These recommendations focus on the core issues associated with Action Plan Recommendation 5, and are limited to the May Valley Subarea. They do not address other recommendations or subareas described in the Action Plan. These recommendations identify actions and opportunities outside the scope of Recommendation 5, or that lie outside the May Valley Subarea, that would be expected to help address issues associated with Recommendation 5. The following overarching recommendations are offered as guidance to the use of information and conceptual project designs summarized in this report and detailed in Appendix C: 1. Implement a finite number of priority conceptual projects to serve as demonstration projects, 2. Monitor demonstration projects for effectiveness. 3. Refine designs and implement additional projects based on demonstration project findings, and 4. Explore opportunities to use methods or implement actions in areas beyond the scope of Recommendation 5. PRIORITIZED CONCEPTUAL PROJECTS Figure 12 provides a comprehensive view of the May Valley Subarea, including the locations of the 33 conceptual restoration projects. The 33 conceptual projects are relatively evenly distributed throughout the May Valley Subarea with some concentration of projects in areas subject to severe flooding, priority habitat areas, or other priority issues. The following summarizes prioritization results and provides reach- specific recommendations. Reach 1 Six conceptual restoration projects and the lower-most portion of another project were identified in Reach I (Figure 13). Conceptual project designs included a wide variety of project types including: streambank protection and instream habitat enhancement, grade control, high-flow side channels, riparian habitat enhancement and wetland habitat enhancement project types, and direct in-channel alteration. All projects identified in Reach I were determined to provide some degree of mitigation to the issues identified (see Appendix B for details). The prioritization process identified Project 4 -Hydraulic Control and High-flow Channel (see Appendix B) -as the highest priority project in Reach I and the fourth highest priority of the 33 Projects. Project 4 should be considered a candidate project for early implementation as a demonstration project as part of the May Valley Habitat Enhancement project. Reach 2 I I I I I . ' I I I Nine conceptual restoration projects and the upstream-most portion of another project were identified in I Reach 2 (Figure 14). Conceptual project designs include culvert (conveyance), high-flow side channels, riparian habitat enhancement and wetland habitat enhancement project types, and direct in-channel alteration. All projects identified in Reach 2 were determined to provide some degree of mitigation to Iii identified issues (see Appendix B for details). The prioritization process identified Project 7 -148'h Avenue ID SE Culvert and High-flow Channel (see Appendix B for details) as the highest priority project in Reach 2; this project is the highest priority project in the May Valley sub-area. Project 1 should be considered a top ~ File No. 10791-005-00 December 19, 2008 Page34 GEOENGINURS_B I I I I I I I I I I I I I I I I I I I I priority candidate project for early implementation as a demonstration project as part of the May Valley Habitat Enhancement project. Reach 3 Three conceptual restoration projects and the lower-most portion of another project were identified in Reach 3 (Figure 15). Conceptual project designs include tributary passage, side-channel passage, conveyance improvement, beaver management, riparian habitat enhancement and wetland habitat enhancement project types, and direct in-channel alteration. All projects identified in Reach 3 were determined to provide some degree of mitigation to identified issues (sec Appendix B for details). The prioritization process identified Project 17 -Beaver Management Demonstration Project (see Appendix B for details) -as the highest priority project in Reach 3; this project is the second highest priority project in the May Valley sub-area. Project 17 should be considered a top priority candidate project for early implementation as a demonstration project as part of the May Valley Habitat Enhancement project. Implementation of Project 17 should be coordinated with plans to implement Project 18. Reach 4 Five conceptual restoration projects and the central portion of another project were identified in Reach 4 (Figure 16). Conceptual project designs include floodwater conveyance, tributary stormwater, riparian habitat enhancement and wetland habitat enhancement project types, and direct in-channel alteration. All projects identified in Reach 4 were determined to provide some degree of mitigation to issues identified (see Appendix B for details). The prioritization process identified Project 18 -I 64'h Avenue SE Conveyance Project (see Appendix B for details) -as the highest priority project in Reach 4, it is the third highest priority project in the May Valley sub-area. Expected benefits of Project 18 were projected based on coordination of implementation with Project 17 in Reach 3. Project 18 should be considered a top priority candidate project for early implementation as a demonstration project as part of the May Valley Habitat Enhancement project. Reach 5 Six conceptual restoration projects and the up-stream and downstream portions of two other projects were identified in Reach 5 (Figure 17). Conceptual project designs include floodwater conveyance ( culverts), tributary riparian and aquatic habitat enhancement, coho salmon off-channel rearing habitat enhancement, wetland habitat enhancement project types, and direct in-channel alteration. All projects identified in Reach 5 were determined to provide some degree of mitigation to issues identified (sec Appendix B for details). The prioritization process identified Project 28 -Wetland Habitat Enhancement (WSDOT South, see Appendix B for details) -as the highest priority project in Reach 5. This project is ranked 9th of 33 projects in the sub-area. Project 28 may be a candidate project for early implementation as a demonstration project as part of the May Valley Habitat Enhancement project. Reach 6 One conceptual restoration project and the up-stream portion of another project was identified in Reach 6 (Figure 18). Conceptual project designs were limited to a potential high flow and sediment detention basin project. The detention basin project identified in Reach 6 was determined to provide some, minor, mitigation to issues identified (see Appendix B for details). The prioritization process identified Project 29 - North Fork High Flow Detention Basins (see Appendix B for details) as relatively low priority (number 23 of 33), in the May Valley sub-area. Project 29 should not be considered a priority project for early implementation as a demonstration project as part of the May Valley Habitat Enhancement project. File No. !0791-005-00 Decemher 19, 2008 Page 35 GEOENGINEERS_ai' OTHER ALTERNATIVE ACTIONS RECOMMENDED FOR CONSIDERATION In the process of developing conceptual project designs to address issues identified in Recommendation 5 of the Action Plan (King County 200 I), a number of potential solutions were identified but determined to be outside the scope of this project. GeoEngineers elected to exclude these projects from the conceptual project designs list (Appendix B), but to include them in this Recommendations section because of the benefit they would bring to the May Valley sub-area. Brief descriptions of these projects are summarized below. o Highlands and Renton Plateau Stormwater Treatments: One of the most significant issues exacerbating flooding in the May Valley, as identified in the Conditions Report (King County 1995) and this Conceptual Restoration, is the increase in impervious surfaces ( and thus stormwater runoff) in the Highlands and Renton Plateau Subareas. The Conditions Report (King County 1995) indicated that increases in the frequency of flooding in the May Valley are a result of development in these headwater areas. Hydrologic analyses completed as part of this CRP provide evidence that the predicted changes have been occurring. Development of stormwater detention, retention, infiltration, dispersion facilities, and reduction of impervious surfaces in the headwater areas should be encouraged to minimize further changes in flood frequency. o Land Acquisition: The May Valley, like many areas in King County, is subject to development pressure. During site visits, staff observed a number of properties for sale. In an area like May Valley where there are limited restoration and flood reduction actions that can be implemented, an alternative may be to use public funds to acquire lands as part of restoration projects. Site specific land acquisition through conservation easements or through fee-simple acquisition may be regulated by public or private land management agencies to protect riparian, wetland and aquatic resources and flood storage. Land acquisition alone, however, will not resolve flooding or habitat problems. Each acquisition must be coupled with the implementation of the proposed restoration project to achieve the desired restoration objective for that area. o Horizontal Directional Drilling below 148'" Avenue SE: One significant geologic feature in the May Valley Subarea that significantly limits options that resource mangers may use to address flooding is the flat topography. The terminal glacial moraine, located downstream from the 148'" Avenue SE Bridge, has produced a very low gradient portion of May Creek running through the May Valley. Not surprisingly, this portion of May Creek in the lower May Valley is subject to frequent flooding. GeoEngineers has successfully used horizontal direction drilling (HOD) to address a variety of issues for clients. Perhaps HOD might be used to produce a managed drainage system in the lower portion of the May Valley, downstream from the 148'" Avenue SE Bridge, to alleviate flooding in this portion of the valley. I I I I I I I LIMITATIONS I Any electronic form, facsimile or hard copy of the original document ( email, text, table, and/or figure), if provided, and any attachments are only a copy of the original document. The original document is stored by I Geo Engineers, Inc. and will serve as the official document of record. Please refer to the appendix titled Report Limitations and Guidelines for Use for additional information I pertaining to use of this report. File No. 1079/-005-00 December I 9, 2008 Page 36 GEOENGINEE~ I I I I I I I I I I I I I I ·• I I I I I I I REFERENCES Bates, K. 2003. Design of Road Culverts for Fish Passage. Washington Department of Fish and Wildlife. Olympia, WA. [Available online] www.wdfw.wa.gov/hab/engincer/cm/culvert manual final.pdf Ehrefeld, J.G. 2000. "Defining the Limits of Restoration: The Need for Realistic Goals". Restoration Ecology Vol. 8, No. I. pp. 2-9. GeoEngineers, Inc. October 2, 2003. Streambank Stability Evaluation. Report to landowner. 7 pp. GeoEngineers, Inc. March 2007. May Valley Habitat Enhancement Project -Draft Pre-Design Report. Submitted to King County and the Mid-Puget Sound Fishery Enhancement Group. 18 p + Appendices. GeoEngineers, Inc. 2007a. Field notes from site visits in Novemrber 2006, February 2007 and July 2007. King County and City of Renton. 200 I. Final Adopted May Creek Basin Action Plan. King County Surface Water Management Division and Renton Department of Public Works, April 2001. Seattle, Washington. King County and City of Renton. 1995. May Creek Current and Future Conditions Report. King County Surface Water Management Division and Renton Department of Public Works, August 1995. Seattle, Washington. King County. 1980. May Creek Basin Plan. King County Surface Water Management Division, Seattle, WA. OTAK. 2006. Technical Memorandum Regarding Hydrologic and Hydraulic Modeling of the May Valley Subarca. 5 pp. Saldi-Caromile, K, K. Bates, P. Skidmore, J. Barenti, and D. Pineo. 2004. Aquatic Habitat Restoration Guidelines, 2004. U.S. Army Corps of Engineers. 2002. Coastal Engineering Manual. Engineer Manual 1110-2-1100, U.S. Army Corps of Engineers, Washington, DC. (In 6 volumes). File No. 1079/-005-00 December /9, 200R Page37 GEOENGINEERS.i GeoENGINEER~ APPENDIX A GIS-BASED FIGURES ·'Ii,• , ifr1i)11" .. :.·' \, •.. ._. "'11 ' ' ,, 11 I· .ii: I " ' .I ··1· ' :''' ,,., :, ' ' ' i,, E' I I I I I I I • Data Sources : Rivers, waterbodies, state highways, and political boundaries are provided by the Washington Department of Transportation. Water Courses are from the King Cou nty Department of Natural Resources. Topographic Hillshade from USGS. Area boundaries were created by Geo Engineers. This map is for information pu rposes. Data were compi l ed from multipl e sources as listed on this map. The data sources do not guarantee these data are accurate or complete . There may have been updates to the data since the publication of t his map . The master file is stored by GeoEngineers, Inc. and will serve as the official record of this communication. The locations of all features shown are approximate . .r May Valley Sub Area c::J subAreas ~ King County Water Courses /'v State Routes 2,000 1,000 0 Feet 2,000 ,, ,- ,, 1\ -~ GeoENGINEERS ti} Vicinity Map FIGURE 1 I I I I I I I I I I I I I I I I I I I This map is for information purposes. Data were compiled from m ultiple sources Data Sources: Rivers , waterbodies , state highways, and politica l boundaries are provided by the as listed on this map. The data sources do not guarantee these data are ~ Washington Department of Transportation. Water Courses are from the King County Department accurate or complete. There may have been updates to the data since the May Valley Sub Area c:JsubAreas , ~ King County Water Courses /'v State Routes 3,000 1,500 0 Feet 3,000 GeoENGINEER~ May Valley Sub Areas ~ of Natural Resources . Topographic Hillshade from USGS . Area boundaries were created by publication of this map. The master file is stored by GeoEngineers, Inc. and will ~ GeoEngineers. serve as the offici~I record of this communication . The locations of all features FIGURE 4 5 shown are approximate. This map is for information purposes. Data were compiled from multiple sources Data Sources: Rivers, waterbodies, state highways, and political boundaries are provided by the as listed on this map . The data sources do not guarantee these data are ~ Wash ing ton Department of Transportation. Water Cou rses are from the King County Department accurate or complete. There may have been updates to the data since the ai of Natural Resources. Topographic Hillshade from USGS. Area boundaries were created by publication of this map. The master file is stored by GeoEngineers, Inc . and will ~ GeoEngineers . serve as the official record of this communication . The locations of all features ~ shown are approximate. 6 N c::J High Fish Use May Valley Sub Area . -- c:JsubAreas ~:~};(\~:;;/J National Wetland Inventory King County Water Courses State Routes 1,000 500 0 Feet 1,000 GEOENGINEERS a May Valley Habitat Features FIGURE 5 Data Sources: Water Courses, Roads, FEMA Floodway and 100 yr Floodplain from King County Department of Natural Resources; Imagery from USGS; 1995 Channel Problems, Deposition and Erosion, and Constrictions were generated by GeoEngineers from hard copy images within the May Creek Conditions Report; All other data created by GeoEngineers. This map is for information purposes. Data were compiled from multiple sources as listed on this map. The data sources do not guarantee these data are accurate or complete . There may have been updates to the data since the publication of this map . The master file is stored by GeoEngineers , Inc. and will serve as the official record of this communication. The locations of all features shown are approximate. D May Valley Reaches Street Centerlines ) Approximate Culvert Locations 2006 (GEi) 0 Known Bridges 2006 (GEi) Watercourses 2006 (GEi) 0 100-Year Floodplain (FEMA) £!, Floodway (FEMA) Channel Problems (Current) ~ Clogged: Vegetation Clogged: Silt Culverts: Fish-impass Channel Problems (1995 Conditions Report) c::J Erosion c::J Erosion; Stream habitat c::J Fish habitat; Flooding -_ Flooding c::J stream habitat o Clogged o Deposition o Erosion o Gravel o Hard bed • Old Beaver Dam o Dense Vegetation • Submerged Obstruction 250 125 0 Feet 250 GEOENGINEERS CJ MAY CREEK HABITAT RESTORATION Reach 1 FIGURE 6 Data Sources : Water Courses, Roads , FEMA Floodway and 100 yr Floodplain from King County Department of Natural Resources; Imagery from USGS; 1995 Channel Problems, Depos ition and Erosion , and Constrictions were generated by GeoEngineers from hard copy images within the May Creek Conditions Report; All other data created by GeoEngineers. This map is for information purposes. Data were compiled from multiple sources as li sted on this map . The data sources do not guarantee these data are accurate or complete. There may have been updates to the data since the publication of this map. The master file is stored by GeoEngineers, Inc. and will serve as the official record of this communication . The locations of all features shown are approximate. D May Valley Reaches Street Centerlines ) Approximate Culvert Locations 2006 (GEi) 0 Known Bridges 2006 (GEi) Watercourses 2006 (GEi) 0 100-Year Floodplain (FEMA) (!, Floodway (FEMA) Channel Problems (Current) ~Clogged: Vegetation Clogged: Silt Culverts: Fish-impass Channel Problems (1995 Conditions Report) C]Erosion C] Erosion; Stream habitat C] Fish habitat; Flooding -_ Floodirtg C] Stream habitat 0 Clogged 0 Deposition 0 Erosion Gravel 0 Hard bed • Old Beaver Dam 0 Dense Vegetation • Submerged Obstruction 450 225 0 Feet 450 GEOENGINEERS (() MAY CREEK HABITAT RESTORATION Reach 2 FIGURE 7 Data Sources: Water Courses, Roads, FEMA Floodway and 100 yr Floodplain from King County Department of Natural Resources; Imagery from USGS; 1995 Channel Problems, Deposition and Erosion, and Constrictions were generated by GeoEngineers from hard copy images within the May Creek Conditions Report; All other data created by GeoEngineers . Thi s map is for infonnation purposes. Data were compiled from multiple sources as listed on this map. The data sources do not guarantee these data are accurate or complete . There may have been updates to the data since the publication of this map. The master file is stored by GeoEngineers, Inc. and will serve as the official record of this communication. The locations of all features shown are approximate. (::J May Valley Reaches Street Centerlines ) Approximate Culvert Locations 2006 (GEi) 0 Known Bridges 2006 (GEi) Watercourses 2006 (GEi) 0 100-Year Floodplain (FEMA) £!> Floodway (FEMA) Channel Problems (Current) """"'""Clogged: Vegetation Clogged: Silt Culverts: Fish-impass Channel Problems (1995 Conditions Report) c:JErosion c:J Erosion; Stream habitat c:J Fish habitat; Flooding r= _ Flooding c:J Stream habitat o Clogged o Deposition O Erosion O Gravel 0 Hard bed • Old Beaver Dam 0 Dense Vegetation • Submerged Obstruction 350 175 0 Feet 350 GEoENGINEERS CJ MAY CREEK HABITAT RESTORATION Reach 3 FIGURE 8 Data Sources: Water Cour ses, Roads, FE MA Floodway and 100 yr Floodplain from King County Depa rtm ent of Natural Resources; Imagery from USGS; 1995 Channel Problems, Deposition and Erosion, a nd Constrictions were generated by GeoEngineers from hard copy images within the May Creek Conditions Report; All other data created by GeoEngineers. This map is for information purposes. Data were compiled from m ultiple sources as listed o n this map. Th e data sources do not guaran tee these d ata a re accurate or complete. Th e re may have been updates to the d ata sin ce th e publication of this map. The master file is stored by GeoEngineers, Inc. and will serve as the official record of this communication . The locations of all features shown are approximate. Street Centerl ines ) Approximate Culvert Locations 2006 (GEi) 0 Known Bridges 2006 (GEi ) Watercourses 2006 (GE i) 0 100-Year Floodplai n (FEMA) C, Floodway (FEMA) Channel Problems (Current) ~ Clogged: Vegetation Clogged : Silt Culverts: Flsh-impass ~Erosion Channel Problems (1995 Conditions Report) c:::J erosion c:::J erosion ; Stream habitat c:::J Fish habitat; Flooding -__ Flooding c:::J stream habitat o Clogged o Deposition o Erosion • Grav el O Ha rd bed • Old Beaver Dam o Dense Vegetation • Submerged Obstruction 350 175 0 Feet 350 GEOENGINEERS CJ MAY CREEK HABITAT RESTORATION Reach 4 FIGURE 9 Data Sources: Water Courses, Roads, FEMA Floodway and 100 yr Floodplain from King County Department of Natural Resources ; Imagery from USGS; 1995 Channel Problems, Deposition and Erosion , and Constrictions were generated by GeoEngineers from hard copy images within the May Creek Conditions Report; All other data created by GeoEngineers . This map is for information purposes. Data were compiled from multiple sources as listed on this map. The data sources do not guarantee these data are accurate or complete. There may have been updates to the data since the publication of this map. The master file is stored by GeoEngineers, Inc. and will serve as the official record of this communication . The locations of all features shown are approximate. D May Valley Reaches Street Centerlines ) Approximate Culvert Locations 2006 (GEi) 0 Known Bridges 2006 (GEi) Watercourses 2006 (GEi) 0100-Year Floodplain (FEMA) C, Floodway (FEMA) Channel Problems (Current) ~ Clogged: Vegetation Clogged: Silt Culverts: Fish-impass Channel Problems (1995 Conditions Report) CJErosion CJ Erosion; Stream habitat CJ Fish habitat; Flooding -_ Flooding CJ Stream habitat O Clogged o Deposition o Erosion Gravel o Hard bed • Old Beaver Dam o Dense Vegetation • Submerged Obstruction 350 175 0 Feet 350 GEOENGINEERS C) MAY CREEK HABITAT RESTORATION Reach 5 FIGURE 10 Data Sources: Water Courses, Roads, FEMA Floodway and 100 yr Floodplain from King County Department of Natural Resources; Imagery from USGS ; 1995 Channel Problems , Deposition and Er osion, and Constrictions were generated by GeoEngineers from hard copy images within the May Creek Conditions Report; All other data created by GeoEngineers. This map is for informati on purposes. Data w ere compiled from multiple sources as listed on this map. The data sources do not guarantee these data are accurate or complete. There may have been updates to the data sin ce the publication of this map. The master file is stored by GeoEngineers, Inc. and will serve as the official record of this communication. The locations of all features shown are approximate. D May Valley Reaches Street Centerl ines ) Approximate Culvert Locations 2006 (GEi) 0 Known Bridges 2006 (GEi) Watercourses 2006 (GEi) 0 100-Year Floodplain (FEMA) (!, Floodway (FEMA) Channel Problems (Current) ~Clogged: Vegetation Clogged: Silt Culverts: Fish-impass Channel Problems (1995 Conditions Report) 0 Erosion D Erosion; Stream habitat 0 Fish habitat; Flooding =-, Flooding c:J stream habitat O Clogged O Deposition o Eros io n Gravel O Hard bed • Old Beaver Dam O Dense Vegetation • Submerged Obstruction 600 300 0 Feet 600 GEoENGINEERS C} MAY CREEK HABITAT RESTORATION Reach 6 FIGURE 11 Dat a Sources: Wate r Courses and roads from King County Department of Natural Resou rces . Imagery from USGS and ESRI. Reach boundaries and conceptual projects created by GeoEngineers. This map is for information purposes. Data were compiled from multipl e sources as listed on this map. The data sources do not guarantee these data are accurat e or complete. The re may have been up dates t o the data si nce th e publication of this map. The master file is sto red by GeoEngineers , Inc. and will serve as the official record of this communication . The locations of all features shown are approximate. 1 Project Number • 4·5 River Mile 0.5 mi 4-+ lnnefective Flow Projects {IFP) -New Pool Habitat D Detention Basin ~ Beaver Management Culvert -Streambank Protection Erosion Control Restored lnstream Habitat ------~ 12::..J ~ D New High-Flow Channel New Channel Alignment New Side Channel Riparian Features Created Wetland Enhanced Wetland Buffer Watercourses 2006 (GEi) May Valley Reaches D N 1,500 750 0 Feet 1,500 GEoENGINE ER~ MAY CREEK HABITAT RESTORATION Conceptual Projects All FIGURE 12 ------------------~ Data Sources: Water Courses and roads from Ki ng County Department of Natural Reso urces . Imagery from USGS and ESRI. Rea c h boundaries and conceptual projects created by GeoEngineers. This map is for information purposes. Data were com piled from multiple sources as listed on this map . The data sources do not guarantee these data are accurate or complete. The re may have been updates t o the data since the publication o f this map. The master fil e is stored by GeoEngineers , Inc. and will se rve as the official record of this communication. The locations of all features shown are approxima te . 1 Project Number .... 5 River Mile 0 .1 mi ... lnnefective Flow Projects (IFP) -New Pool Habitat D Detention Basin E22d Beaver Management Culvert -Streambank Protection Erosion Control -Restored lnstream Habitat -New High.flow Channel ••• New Channel Alignment -New Side Channel -Riparian Features ~ ··:,:J Created Wetland ~ Enhanced Wetland Buffer Watercourses 2006 (GEi) D May Valley Reaches ~ N 250 125 0 Feet 250 G eo EN GINE ERS t{) MAY CREEK HABITAT RESTORATION Conceptual Projects Reach 1 FIGURE 13 Data Sou rces : Water Courses and roads from King County Department of Natural Resources. Imagery from USGS and ESRI. Reach boundaries and conceptual projects created by GeoEngineers. This map is for info nnation pu rposes. Data we r e com piled from multiple sources as listed on this map. The data sources do not guarantee th ese data a re accurate or complete . There may have been updates to the data since the publication of this map. The master file is stored by GeoEngineers, Inc. and will serve as the official record of this communication. The locations of all features shown are approximate. 1 Project Number .4 .5 River Mile 0 .1 m i ..,. lnnefecti ve Flow Projects (IFP) -New Pool Habitat D Detention Basin ~ Beaver Management Culvert -Streambank Protection Erosion Control -Restored lnstream Habitat -New High-Flow Channel ---New Channel Alignment -New Side Channel -Ripari an Features ~ ·.~·j Created Wetland ~ Enhanced Wetland Buffer Watercourses 2006 (GEi) D May Valley Reaches 6 N 500 250 0 Feet 500 GEOENGINEERS CJ MAY CREEK HABITAT RESTORATION Conceptual Projects Reach 2 FIGURE 14 Data Sources: Water Courses and roads from King County Department of Natural Resources. Imagery from USGS and ESRI. Reach boundaries and conceptual projects created by GeoEngineers. This map is for information purposes. Data were compiled from multiple sources as listed on this map. The data sources do not guarantee these data are accurate or complete. There may have been updates to the data since the publication of this map. The master file is stored by GeoE ngineers, Inc. and will se rve as the official record of this communication. The locations of all features shown are approximate . 1 Project Number e 4·5 River Mile 0.1 mi ..... lnnefective Flow Projects (IFP) -New Pool Habitat D Detention Bas in ~ Beaver Management Culvert -Streambank Protection Erosion Control Restored lnstream Habitat -New High-Flow Channel ---New Channel Alignment -New Side Channel -Riparian Features ~ ··J Created Wetland ~ Enhanced Wetland Buffer Watercourses 2006 (GEi) D May Valley Reaches 6 N 250 125 0 Feet 250 GEOENGINEERS C) MAY CREEK HABITAT RESTORATION Conceptual Projects Reach 3 FIGURE 15 Data Sources: Water Courses and roads from King County Department of Natural Resources . Imagery from USGS and ESRI. Reach bou ndaries and conceptual projects created by GeoEngineers. This map is for information purposes. Data were compiled from m ultipl e sources as listed on this map. The data sources do not guara ntee these data are accurate or complete. There may have been updates to the data since th e publication of this map. The master file is sto red by GeoEngineers, Inc. and will serve as the official record of this communication . The locations of all features shown are approximate. 1 Project Number e 4·5 River M ile 0 .1 m i ..... lnnefective Flow Projects (IFP) -New Pool Habitat D Detention Basin ~ Beaver Management Culvert -Streambank Protection Erosion Control -Restored lnstream Habitat -New High-Flow Channel ••• New Channel Alignment -New Side Channel -Riparian Features b! ·~j Created Wetland ~ Enhanced Wetland Buffer Watercourses 2006 (GEi) D May Valley Reaches D N 250 125 0 Feet 250 GEOENG I NEERS (i} MAY CREEK HABITAT RESTORATION Conceptual Projects Reach 4 FIGURE 16 I I I I I I I I I I I I I I I I I I I Data Sources: Water Courses and roads from Ki ng County Department of Natural Resources . Imagery from USGS and ESRI. Reach boundaries and conceptual projects created by GeoEngineers. This map is for information purposes. Data were compiled from multipl e sources as listed on this map. The data sources do not guar antee these data are accurate or complete. There may have been updates to the data since the publication of this map. The master file is stored by GeoEngineers, Inc. and will serve as the official record of this co mmunication. The locations of all features shown are approximate. 1 Project Number .4.5 River M ile 0.1 mi ...., lnnefective Flow Projects (IFP) -New Pool Habitat D Detention Basin m Beaver Management Culvert -Streambank Protection Erosion Control -Restored lnstream Habit at -New High-Flow Channel ---New Channel Alignment -New Side Channel -Riparian Features ~ ··J Created Wetland ~ Enhanced Wetland Buffer Watercourses 2006 (GEi) D May Valley Reaches D N 250 125 0 Feet 250 GEOENGINEERs@ MAY CREEK HABIT AT RESTORATION Conceptual Projects Reach 5 FIGURE 17 Data Sources: Water Courses and roads from King County Department of Natural Resources. Imagery from USGS a nd ESRI. Reach boundaries and conceptual projects created by GeoEngineers. This map is for information purposes. Data were compi led from multiple sources as listed on this map. The data sources do not guarantee these data are accurate or complete. There may have been updates to th e data since the publication of this map . The master file is stored by GeoEngi ne ers, Inc. and will serve as the official record of this communication . The locations of all features shown are approximate. 1 Project Number • 4·5 River Mile 0 .1 mi .. lnnefective Flow Projects (IFP) -New Pool Habitat D Detention Basin (2Z] Beaver Management Culvert -Streambank Protection Erosion Control Restored lnstream Habitat ------~ ~ ~ D New High-Flow Channel New Channel Alignment New Side Channel Riparian Features Created Wetland Enhanced Wetland Buffer Watercourses 2006 (GEi) May Valley Reaches 6 N 500 250 0 Feet 500 GEOENGINEERS C) MAY CREEK HABITAT RESTORATION Conceptual Projects Reach 6 FIGURE 18 I I I I I I I I I I I I I I I I I I I GEoENGINEER~ APPEND/XS CONCEPTUAL PROJECT DESCRIPTIONS . '\ . ' _, ,, TABLE OF CONTENTS (CONTINUED) Page No. PROJECT 1: STREAMBANK PROTECTION AND INSTREAM HABITAT ENHANCEMENT ....... B-1 Site Location ........................................................................................................................... B-1 Site Description ...................................................................................................................... B-1 Project Description ................................................................................................................. B-1 Project Efficacy ....................................................................................................................... B-3 Potential Challenges and Limitations ..................................................................................... B-3 Planning-Level Cost Estimates ............................................................................................... 9-3 Permitting ................................................................................................................................ 9-3 PROJECT 2: 143"0 AVENUE SE BRIDGE CROSSING ................................................................ 9-4 Site Location ........................................................................................................................... 9-4 Site Description ...................................................................................................................... B-4 Project Description ................................................................................................................. B-6 Project Efficacy ....................................................................................................................... B-6 Potential Challenges and Limitations ..................................................................................... B-6 Planning-Level Cost Estimates ............................................................................................... B-6 Permitting ................................................................................................................................ 8-6 PROJECT 3: STREAMBANK AND OFF-CHANNEL HABITAT ENHANCEMENT ......................... 8-7 Site Location ........................................................................................................................... B-7 Site Description ...................................................................................................................... B-7 Project Description ................................................................................................................. 8-8 Project Efficacy ....................................................................................................................... 8-8 Potential Challenges and Limitations ................................................................................... B-1 0 Planning-Level Cost Estimates ............................................................................................. B-1 O ~~~~ .............................................................................................................................. ~10 PROJECT 4: HYDRAULIC CONTROL AND HIGH-FLOW CHANNEL ........................................ 9-11 Site Location ......................................................................................................................... B-11 Site Description .................................................................................................................... B-11 Project Description ............................................................................................................... B-11 Project Efficacy ..................................................................................................................... B-13 Potential Challenges and Limitations ................................................................................... B-13 Planning-Level Cost Estimates ............................................................................................. B-13 Permitting .............................................................................................................................. 8-14 PROJECT 5: WETLAND ENHANCEMENT/REED CANARYGRASS ABATEMENT ................... 8-15 Site Location ......................................................................................................................... 8-15 Site Description .................................................................................................................... B-15 Project Description ............................................................................................................... B-15 Project Efficacy ..................................................................................................................... B-15 Potential Challenges and Limitations ................................................................................... B-17 Planning-Level Cost Estimates ............................................................................................. B-17 Permitting .............................................................................................................................. 9-17 File No. 10791-005-00 December J 9, 2008 Page 8-i GEOENGINEE~ I I I I I I I I I I I I I I I I I I I I TABLE OF CONTENTS (CONTINUED) Page No. PROJECT 6: GREENE'S CREEK CONFLUENCE PROJECT -POND/WETLAND ENHANCEMENT .................................................................................................... B-18 Site Location ......................................................................................................................... B-18 Site Description .................................................................................................................... B-18 Project Description ............................................................................................................... B-18 Project Efficacy ..................................................................................................................... B-18 Potential Challenges and Limitations ................................................................................... B-20 Planning-Level Cost Estimates ............................................................................................. B-20 Permitting .............................................................................................................................. B-20 PROJECT 7: 148TH AVENUE SE HIGH-FLOW CONVEYANCE PROJECT ................................ B-21 Site Location ......................................................................................................................... B-21 Site Description .................................................................................................................... B-21 Project Description ............................................................................................................... B-21 Project Efficacy ..................................................................................................................... B-21 Potential Challenges and Limitations ................................................................................... B-23 Conceptual Designs and Planning-Level Cost Estimates .................................................... B-23 Permitting .............................................................................................................................. B-23 PROJECT 8: WETLAND ENHANCEMENT/REED CANARYGRASS ABATEMENT PROJECT .B-24 Site Location ......................................................................................................................... B-24 Site Description .................................................................................................................... B-24 Project Description ............................................................................................................... B-24 Project Efficacy ..................................................................................................................... B-24 Potential Challenges and Limitations .................................................................................. .8-26 Conceptual Designs and Planning-Level Cost Estimates .................................................... B-26 Permitting .............................................................................................................................. B-26 PROJECT 9: LONGMARSH CREEK ENHANCEMENT PROJECT ............................................. B-27 Site Location ......................................................................................................................... B-27 Site Description .................................................................................................................... B-27 Project Description ............................................................................................................... B-27 Project Efficacy ..................................................................................................................... B-27 Potential Challenges and Limitations ................................................................................... B-27 Planning-Level Cost Estimates ............................................................................................. B-29 Permitting .............................................................................................................................. B-29 PROJECT 10: TSEGAY WETLAND ENHANCEMENT/REED CANARYGRASS ABATEMENT .B-30 Site Location ......................................................................................................................... B-30 Site Description .................................................................................................................... B-30 Project Description ............................................................................................................... B-30 Project Efficacy ..................................................................................................................... B-32 Potential Challenges and Limitations ................................................................................... B-32 Planning-Level Cost Estimates ............................................................................................. B-32 Permitting .............................................................................................................................. B-32 File No. /0791-005-00 Decemher /9, 2008 Page B-ii TABLE OF CONTENTS (CONTINUED) Page No. PROJECT 21: HENDRIX CREEK CONFLUENCE AREA PROJECT .......................................... 6-72 Site Location ......................................................................................................................... B-72 Site Description .................................................................................................................... B-72 Project Description ............................................................................................................... B-72 Project Efficacy ..................................................................................................................... B-72 Potential Challenges and Limitations ................................................................................... B-7 4 Planning-Level Cost Estimates ............................................................................................. B-7 4 Permitting .............................................................................................................................. 6-75 PROJECT 22: NORTH HENDRIX WETLAND COMPLEX ........................................................... B-76 Site Location ......................................................................................................................... B-76 Site Description .................................................................................................................... B-76 Project Description ............................................................................................................... 6-76 Project Efficacy ..................................................................................................................... B-76 Potential Challenges and Limitations ................................................................................... B-78 Planning-Level Cost Estimates ............................................................................................. 6-78 Permitting .............................................................................................................................. 6-78 PROJECT 23: COHO OFF-CHANNEL REARING HABITAT (OSBORN PROPERTY) ............... B-79 Site Location ......................................................................................................................... B-79 Site Description .................................................................................................................... B-79 Project Description ............................................................................................................... B-79 Project Efficacy ..................................................................................................................... B-79 Potential Challenges and Limitations ................................................................................... B-81 Project-Level Cost Estimates ............................................................................................... B-81 Permitting .............................................................................................................................. 6-81 PROJECT 24: LOWER COUNTRY CREEK ENHANCEMENT PROJECT .................................. 6-82 Site Location ......................................................................................................................... B-82 Site Description .................................................................................................................... B-82 Project Description ............................................................................................................... 6-82 Project Efficacy ..................................................................................................................... 6-82 Potential Challenges and Limitations ................................................................................... B-84 Planning-Level Cost Estimates ............................................................................................. 6-84 Permitting .............................................................................................................................. 6-84 PROJECT 25: CABBAGE CREEK CULVERT REPLACEMENT .................................................. B-85 Site Location ......................................................................................................................... B-85 Site Description .................................................................................................................... B-85 Project Description ............................................................................................................... B-87 Project Efficacy ..................................................................................................................... B-88 Potential Challenges and Limitations ................................................................................... B-89 Planning-Level Cost Estimates ............................................................................................. B-89 Permitting .............................................................................................................................. B-89 File No. I 0791-005-00 December /9, 2008 Page 8-v GEOENGINUR~ I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I TABLE OF CONTENTS (CONTINUED) Page No. PROJECT 16: 291-A CONFLUENCE AREA PROJECT .............................................................. 6-53 Site Location ......................................................................................................................... 6-53 Site Description .................................................................................................................... 6-53 Project Description ............................................................................................................... 6-55 Project Efficacy ..................................................................................................................... 6-56 Potential Challenges and Limitations ................................................................................... 6-56 Planning-Level Cost Estimates ............................................................................................. 6-56 Permitting .............................................................................................................................. 6-57 PROJECT 17: MAY CREEK BEAVER MANAGEMENT DEMONSTRATION PROJECT ............ B-58 Site Location ......................................................................................................................... 6-58 Site Description .................................................................................................................... 6-58 Project Description ............................................................................................................... 6-60 Project Efficacy ..................................................................................................................... 6-61 Potential Challenges and Limitations ................................................................................... 6-61 Planning-Level Cost Estimates ............................................................................................. 6-61 Permitting .............................................................................................................................. B-62 PROJECT 18: 164TH AVENUE SE CONVEYANCE PROJECT.. .................................................. 6-63 Site Location ......................................................................................................................... 6-63 Site Description .................................................................................................................... 6-63 Project Description ............................................................................................................... 6-63 Project Efficacy ..................................................................................................................... 6-63 Potential Challenges and Limitations ................................................................................... 6-65 Planning-Level Cost Estimates ............................................................................................. 6-65 Permitting .............................................................................................................................. 6-65 PROJECT 19: TRIBUTARY 291-B CONFLUENCE AREA PROJECT ......................................... 6-66 Site Location ......................................................................................................................... 6-66 Site Description .................................................................................................................... 6-66 Project Description ............................................................................................................... 6-66 Project Efficacy ..................................................................................................................... 6-66 Potential Challenges and Limitations ................................................................................... 6-68 Planning-Level Cost Estimates ............................................................................................. 8-68 Permitting .............................................................................................................................. 6-68 PROJECT 20: STORMWATER/SEDIMENT RETENTION AREA ................................................ 6-69 Site Location ......................................................................................................................... B-69 Site Description .................................................................................................................... 6-69 Project Description ............................................................................................................... 6-69 Project Efficacy ..................................................................................................................... 6-69 Potential Challenges and Limitations ................................................................................... 6-71 Conceptual Designs and Planning-Level Cost Estimates .................................................... 6-71 ~~~~ .............................................................................................................................. ~1 File No. 1079/-005-00 December 19, 2008 Page B-iv GEOENGINE£RS.i TABLE OF CONTENTS (CONTINUED) Page No. PROJECT 21: HENDRIX CREEK CONFLUENCE AREA PROJECT .................................... , ..... 9-72 Site Location ......................................................................................................................... 9-72 Site Description .................................................................................................................... 9-72 Project Description ............................................................................................................... 9-72 Project Efficacy ..................................................................................................................... B-72 Potential Challenges and Limitations ................................................................................... 9-74 Planning-Level Cost Estimates ............................................................................................. 9-74 Permitting .............................................................................................................................. 9-75 PROJECT 22: NORTH HENDRIX WETLAND COMPLEX ........................................................... 9-76 Site Location ......................................................................................................................... 9-76 Site Description .................................................................................................................... 9-76 Project Description ............................................................................................................... 9-76 Project Efficacy ..................................................................................................................... 9-76 Potential Challenges and Limitations ................................................................................... 9-78 Planning-Level Cost Estimates ............................................................................................. 9-78 Permitting .............................................................................................................................. 9-78 PROJECT 23: COHO OFF-CHANNEL REARING HABITAT (OSBORN PROPERTY) ............... 9-79 Site Location ......................................................................................................................... B-79 Site Description .................................................................................................................... 9-79 Project Description ............................................................................................................... 9-79 Project Efficacy ..................................................................................................................... 9-79 Potential Challenges and Limitations ................................................................................... 9-81 Project-Level Cost Estimates ............................................................................................... 9-81 Permitting .............................................................................................................................. 9-81 PROJECT 24: LOWER COUNTRY CREEK ENHANCEMENT PROJECT .................................. 9-82 Site Location ......................................................................................................................... B-82 Site Description .................................................................................................................... B-82 Project Description ............................................................................................................... 9-82 Project Efficacy ..................................................................................................................... 9-82 Potential Challenges and Limitations ................................................................................... 9-84 Planning-Level Cost Estimates ............................................................................................. 9-84 Permitting .............................................................................................................................. 9-84 PROJECT 25: CABBAGE CREEK CULVERT REPLACEMENT .................................................. 9-85 Site Location ......................................................................................................................... B-85 Site Description .................................................................................................................... B-85 Project Description ............................................................................................................... 9-87 Project Efficacy ..................................................................................................................... 9-88 Potential Challenges and Limitations ................................................................................... 9-89 Planning-Level Cost Estimates ............................................................................................. 9-89 Permitting .............................................................................................................................. 9-89 File No. /079/-005-00 December 19, 2008 Page 8-v GEOENGINEERS-"7 I I I I I I I I I I I I I I I I I I I I • ll I I I I I I I I I TABLE OF CONTENTS (CONTINUED) Page No. PROJECT 26: COUNTRY CREEK CULVERT REPLACEMENT ................................................. 8-91 Site Location ......................................................................................................................... 8-91 Site Description .................................................................................................................... 8-91 Project Description ............................................................................................................... 8-93 Project Efficacy ..................................................................................................................... 8-95 Potential Challenges and Limitations ................................................................................... 8-95 Planning Level Cost Estimates ............................................................................................. 8-96 Permitting .............................................................................................................................. 8-96 PROJECT 27: COUNTY -CABBAGE CREEK CULVERT REPLACEMENT ................................. 8-97 Site Location ......................................................................................................................... 8-97 Site Description .................................................................................................................... 8-97 Project Description ............................................................................................................... 8-99 Project Efficacy .................................................................................................................. B-100 Potential Challenges and Limitations ................................................................................ B-100 Planning Level Cost Estimates .......................................................................................... B-101 Permitting ........................................................................................................................... B-101 PROJECT 28: WETLAND HABITAT ENHANCEMENT PROJECT (WSDOT SOUTH) ............ B-102 Site Location ...................................................................................................................... B-102 Site Description ................................................................................................................. B-102 Project Description ............................................................................................................ B-102 Project Efficacy .................................................................................................................. B-102 Potential Challenges and Limitations ................................................................................ B-104 Planning-Level Cost Estimates Planning Level Cost Estimates ....................................... B-104 Permitting ........................................................................................................................... B-104 PROJECT 29: DETENTION PROJECT-NORTH FORK MAY CREEK (WSDOT EAST) ....... 8-105 Site Location ...................................................................................................................... B-105 Site Description ................................................................................................................. B-105 Project Description ............................................................................................................ B-105 Project Efficacy .................................................................................................................. B-105 Potential Challenges and Limitations ................................................................................ B-107 Planning-Level Cost Estimates .......................................................................................... B-107 Permitting ........................................................................................................................... B-107 PROJECT IFP1: INEFFECTIVE FLOW PROJECT 1 -287D TO INDIAN MEADOW CREEK. B-108 Site Location ...................................................................................................................... B-108 Site Description ................................................................................................................. B-108 Project Description ............................................................................................................ B-108 Project Efficacy .................................................................................................................. B-109 Potential Challenges and Limitations ................................................................................ B-111 Planning-Level Cost Estimates .......................................................................................... B-111 Permitting ........................................................................................................................... B-111 File No. 1079/-005-00 Decemher 19. 2008 Page 8-vi GEOENGINEERS_B TABLE OF CONTENTS {CONTINUED) Page No. PROJECT IFP 2: INEFFECTIVE FLOW PROJECT 2 -UPPER COLASURDO PASTURE .... B-112 Site Location ...................................................................................................................... B-112 Site Description ................................................................................................................. B-112 Project Description ............................................................................................................ B-112 Project Efficacy .................................................................................................................. B-113 Potential Challenges and Limitations ................................................................................ B-115 Planning-Level Cost Estimates .................................................................................. ··: ..... B-115 Permitting ........................................................................................................................... B-115 PROJECT IFP-3: INEFFECTIVE FLOW PROJECT 3 -291-A TO HENDRIX CREEK ............ B-117 Site Location ...................................................................................................................... B-117 Site Description ................................................................................................................. B-117 Project Description ............................................................................................................ B-117 Project Efficacy .................................................................................................................. B-118 Potential Challenges and Limitations ................................................................................ B-120 Planning-Level Cost Estimates .......................................................................................... B-120 Permitting ........................................................................................................................... B-120 PROJECT IFP4: INEFFECTIVE FLOW PROJECT 4 -NORTH FORK MAY CREEK .............. B-122 Site Location ...................................................................................................................... B-122 Site Description ................................................................................................................. B-122 Project Description ............................................................................................................ B-122 Project Efficacy .................................................................................................................. B-123 Potential Challenges and Limitations ................................................................................ B-123 Planning-Level Cost Estimates .......................................................................................... B-125 Permitting ........................................................................................................................... B-125 File No. 1079 l ·005-00 December 19, 2008 Page 8-vii GEOENGINEEft!lV I I I I I Ii ti I I I • I I I I I I I I I I I I I I I I I I I PROJECT 1: 5TREAMBANK PROTECTION AND INSTREAM HABITAT ENHANCEMENT This project provides for streambank protection and instream habitat restoration in a 1200 linear feet section of May Creek. This area, as well as all of Reach I, is a transitional area between the May Creek Canyon and the extremely low gradient May Valley. Runoff in the May Creek drainage has increased as the result of three decades of intense upland development and other changes. Channel downcutting and streambank erosion, loss of instream habitat, flooding and siltation are issues in Reach I of the May Creek Habitat Enhancement project area (Figure B-1 ). This project was identified as a Category H project during the prioritization process. Site Location The proposed project site is located between River Mile (RM) 3.95 to RM 4.12 in the SWV.. SEY. of Section 34, Township 24 North, Range 5 East of the Willamette Meridian (T. 24 N., R. 5 E., W.M.) and in the NWV.. NEV.. of Section 3, T. 23 N., R. 5 E., W.M., in King County, near Renton Washington. The project would be completed entirely on private properties located on both banks near River Mile 4.0 (Figure 13, Appendix A). The project site begins approximately 500 feet upstream from the lower- most boundary of the May Valley sub-area and continues approximately 700 feet upstream to the 143'd Avenue SE bridge (Figure 13, Appendix A). Site Description This 1,200-foot section of creek has degraded fish habitat associated with erosion, head-cutting, and channel simplification (Action Plan, King County 2001). The Action Plan characterizes this section of the creek as historically prone to erosion and channel degradation. Therefore, a streambank protection and instream habitat enhancement project is proposed in this area. The GlS database developed by the project team supports these findings. The most prevalent features within this segment of May Creek were erosion and habitat degradation identified as part of the GIS analysis (Figure 6, Appendix A). Erosion problems and recent streambank treatments were observed during recent site visits (2007). Project Description Project 1 would include a combination of streambank treatments on the left bank, instream habitat and channel roughness features, and a high-flow channel braid on the right bank of May Creek. A combination of rock and wood bioengineered structures and riparian streambank treatments would be installed. It is likely that bank barbs, log-crib, and roughened channel elements would also be necessary. The project would help to stabilize the channel, reduce erosion and head-cutting, help stabilize sediment transport, and would enhance fish passage, instream habitat and riparian habitat and function. Any non- native plants found would be removed and replaced with native species. Of any of the 6 reaches in the May Valley Subarea, this reach of May Creek is most readily accessed by anadromous salmonids. Enhancement of passage and habitat in this area is necessary to achieve upstream restoration objectives. Protection of this reach from ongoing erosion and head-cutting is recommended to avoid future impacts from upstream activities, including ongoing development and associated changes in the magnitude and volume of runoff. File No. /079/-005-00 Dccemher /9, 2008 Page 8-1 GEOfNGINEERS_a;I' ~ I 5 \i ~ ~ J j Existing Channel Alignment Conceptual Drawing of Restored Channel and Riparian Area i;; :;1------------------------------1 1:l ,:: Iii a:: GeoENGINEER~ la_lUI Sctonct • fKlulotOi.1) File No. I 0791-005-00 December I 9, 2008 Concep1Ual Drawing Project 1 FIGURE B-1 Page B-2 GeoENGINEeRS.i i I I. I I I I I I I I I I I I I I I I I I I I I· I I I I I I I I I I I I I I Project Efficacy Preliminary hydraulic modeling was completed to evaluate this project together with Project 2. To model the potential hydraulic changes associated with habitat restoration actions, channel roughness was increased within the project area, extending approximately 1,200 feet downstream of the 143"' bridge crossing. The existing channel roughness is estimated to be 0.04. The newly modeled roughness, which incorporates instream habitat, roughened channel features and boulder grade control is estimated to be 0.055. This hypothetical increase in roughness decreases the maximum reach-average velocity at the 2-year event (150 cfs) from 5.1 ft/s to 3.8 ft/s. This would assist in fish migration, and reduce erosional tendencies within the reach. Models predict that local water surface elevations will increase due to these habitat features. At 150 cfs the water surface elevation is predicted to increase approximately 0.4 feet. As this portion of reach I does not flood during the 2-year event, changes in water surface elevation are not expected to effect flooding in the vicinity of the project. Further, models predict that there would be no upstream flood mitigating benefits from this project. However, several other benefits will be created, including: • restoring approximately 1,200 linear feet of instream habitat, • protecting approximately 400 feet of streambank from further erosion, • minimizing channel headcutting through grade-control of approximately 600 feet of channel; and, • increasing high-flow off-channel habitat area with the creation of almost 300 linear feet of channel. Potential Challenges and Limitations The project would need to be developed and completed on the reach scale and would not be effective if implemented only in part. Landowner access permissions would need to be secured across several private properties in order to complete the whole project. In addition, careful analysis of hydraulic and geomorphic condition at this site would be needed to determine if the reach had been significantly altered by the historic construction and operation of a mill pond in the lower portion of the reach. Even though the mill is no longer in operation, it is not evident that the reach has reached dynamic equilibrium. Additional regulatory constraints may also be imposed on the proposed project due to the fact that much of May Creek in the May Valley contains critical habitat areas. A critical areas assessment would need to be completed to determine the extent and function of habitat features at the site. Any impacts to stream buffers, wetlands and wetland buffers would need to be mitigated if the project were pennitted and implemented. Planning-Level Cost Estimates Estimated Construction Costs: $190, I 00 (See Appendix C for details). Design, construction observation and permitting costs are not included as these costs can vary significantly. Permitting A portion of the work will be completed below the ordinary high water mark (OHWM), and require placing fill in a critical area, As a result, the following pennits and approvals likely will be required: • U.S. Army Corps of Engineers (ACOE) Section 404 • Washington State Department offish and Wildlife (WDFW) Hydraulic Project Approval • Washington State Department of Ecology (Ecology) 401 Water Quality Certification • King County Clearing and Grading Permit • SEPA Checklist, with King County lead • King County Critical Areas Review • Compliance with the King County Shoreline Regulations. • Tribal and WDFW area biologist consultation File No. 10791-005-00 Decemher /9, 200/i Page B-3 GEOENGINEERS.i PROJECT 2: 143RD AVENUE SE BRIDGE CROSSING Project 2 proposes to protect and enhance aquatic habitat and fish passage, while reducing headcutting and erosion risk at the proposed project site. As mentioned in Project l, runoff in the May Creek drainage has increased as the result of three decades of intense upland development. Channel downcutting and streambank erosion is an issue in Reach l, a transitional area between the May Creek Canyon segment and the extremely low gradient May Valley (Figure 8-2). This project was identified as a Category H project during the prioritization process. Site Location Project 2 is located immediately downstream from a bridge crossing located at the intersection of 143"' Avenue SE and May Creek near RM 4.22 in the SEY. of Section 34, T. 24 N., R. 5 E., W.M., of King County, near Renton Washington (Figure 13, Appendix A). The project would occur in the stream channel accessed through private property located on both banks of May Creek at the crossing. Site Description As part of previous work at the project site to assess the potential for streambank erosion, GeoEngineers (2003) measured the opening of the open-bottom arch culvert bridge, measured as a l 5-foot span with a 7-foot rise. A rectangular culvert 3 feet wide by 2 feet high was identified at a location through the embankment adjacent to the pipe arch and about 3 feet above the stream bottom. It was assumed that the rectangular culvert was installed to provide additional capacity for flood flows. GeoEngineers (2003) estimated the maximum opening of the combined culverts as approximately 83 square feet. However, it would require a water depth greater than about 3 to 4 feet above the streambank to utilize this full opening. GeoEngineers (2003) estimated only about 45 square feet of opening through the culverts for a water depth at the top of the streambank. Consequently, the culvert openings will be the limiting factor for flood flows through this channel reach. A recently completed flood insurance study completed by Federal Emergency Management Agency (FEMA 1999) indicated that the IOO-year flood elevation at the l 43'd Avenue SE arch culvert had an elevation of 304.5 feet. The FEMA study also indicated a floodway width of 15 feet, a maximum section area of 78 square feet, and a mean velocity of 8.2 feet per second. FEMA data was used to compute a maximum flow depth for a IOO-year event, resulting in a depth of about 3.0 to 3.5 feet at the arch culvert. The bridge crossing over May Creek is used by several private landowners to access their residences. The bridge was constructed with concrete in the l950's. Various activities, including bridge construction have altered hydraulic processes at the site. This has increased erosive forces, resulting in scour and erosion at the site and downstream as well as habitat simplification. This portion of May Creek was identified in Action Plan (200 I) as having a stream habitat problem associated with erosion and habitat simplification. This area is also characterized in the Action Plan (King County 2001) and the Conditions Report (King County 1995) as being subject to flooding, erosion, degraded stream fish habitat and related problems. The Action Plan characterizes this section of the creek as historically prone to erosion and channel degradation. Erosion problems were observed .downstream from the 143'd Avenue SE bridge during recent site visits (GeoEngineers 2007a). GeoEngineers has previously assisted landowners with erosion and flooding issues upstream from this site (GeoEngineers 2003). The GIS database developed by the project team supports these findings. The most prevalent features identified in this segment during the GJS development include erosion and habitat degradation (Figure 6, Appendix A). File No. 1079/-()05-00 December 19, 2008 PageB-4 GeoENGINEeR!.@ I I I I I I I I I I I I I I I I I I I I I I I I I I I Existing channelunder 14Jfd'Ave bridge " I cl: ~ t 0. 15 I ~ I ' ·, \ I I \ I I ---' ·--· ' -. concei»ual. dr~ng of channel an~ habitat bolder grade control el~!Ylents ~1---------------.......... -------------------t 6 ~ 0: GEOENGINEER~ Ul'UI SciLUJCe + Tttf:tt:Gtorr File No. /079/-005-00 Decemhe1· 19, 2008 Conceptual Drawing rroject 2 Ht;UHt 11,Z Page B-5 GEOfNGINEERS.i Project Description This project would include installation of grade control, roughened channel, instream habitat, and bridge footer reinforcement treatments. The primary purpose of the project would be to reduce erosion and head-cutting occurring at the site to protect the bridge from failure. Secondary objectives would include improvements to fish passage and rearing habitat quality. Development of this project might serve to mitigate impacts from upslope activities, including increased runoff volume and intensity, as the result of the development of impervious surfaces in headwater areas. Project Efficacy The potential hydraulics effects of Projects I and 2 were modeled together. The projected increase in roughness was predicted to decrease the maximum reach average velocity at the 2-year event (150 cfs) from 5.1 ft/s to 3.8 ft/s. This would assist in fish migration, and reduce erosional tendencies within the reach. Local water surface elevations were predicted to increase due to these habitat features. At 150 cfs the water surface elevation is predicted to increase approximately 0.4 feet. Modeling predicted no upstream flooding benefits for this project. This result is not surprising as Projects I and 2 were developed to address local erosion issues and potentially serve to mitigate any effects from implementation of projects upstream. Potential Challenges and Limitations The existing 143rd Ave SE bridge was privately designed, constructed, and installed. The primary responsibility for the maintenance and improvement of this structure is therefore a private matter. The maintenance and improvement of the stream channel and habitat in the area of the bridge may, however, be an appropriate use of public funds. Landowners must grant permission for these projects to be implemented. Any work in or around the private bridge must, however, be coordinated with private landowners. The work should also be done in concert with other reach-based habitat enhancement and erosion control projects (see Projects I and 3). Additional regulatory constraints may also be imposed on the proposed project due to the fact that much of May Creek in the May Valley contains critical habitat areas. A critical areas assessment would need to be completed to determine the extent and function of habitat features at the site. Any impacts to stream buffers, wetlands and wetland buffers would need to be mitigated if the project were permitted and implemented. Planning-Level Cost Estimates Estimated Construction Costs: $148,500 (See Appendix C for details). Design, construction observation and permitting costs are not included as these costs can vary significantly. Permitting A portion of the work will be completed below the ordinary high water mark (OHWM), and require placing fill in a critical area. As a result, the following permits and approvals likely will be required: • U.S. Army Corps of Engineers (ACOE) Section 404 • Washington State Department of Fish and Wildlife (WDFW) Hydraulic Project Approval, potential consultation with USFWS • Washington State Department of Ecology (Ecology) 401 Water Quality Certification • King County Clearing and Grading Permit • SEPA Checklist, with King County lead • King County Critical Areas Review • Compliance with the King County Shoreline Regulations • Tribal and WDFW area biologist consultation File No. 1079/-005-00 December 19, 2008 Page B-6 GeoENGINEERS_y} i r(i .. ll Ii @J I I I I I ·• I I I I I I I I I I I I I I I PROJECT 3: STREAMBANK AND OFF-CHANNEL HABITAT ENHANCEMENT Project 3 is another project proposed for implementation in Reach I. This project would protect and enhance aquatic habitat and fish passage, while reducing erosion risk in a 500-linear-foot section of May Creek (Figure B-3). This project was identified as a Category L project during the prioritization process. Site Location The proposed project site is located at 9524 143'd Avenue SE between RM 4.12 to 4.23, in the SEY.. of Section 34, T. 24 N., R. 5 E., W.M. in King County, near Renton Washington (Figure 13, Appendix A). Project 3 is proposed for approximately 500 linear feet of May Creek located immediately upstream from the 143"1 Avenue bridge crossing May Creek. The project would occur entirely on private properties located on both banks of May Creek upstream from the 143'h Avenue bridge crossing May Creek near River Mile 4.22. Site Description As part of previous work completed by GeoEngineers (2003) at this site, it was observed that the stream alignment causes the streamflow to impinge the left (south) streambank near the upstream (eastern) end of the retaining wall adjacent the Madfai property, at an angle of about 45 degrees. The stream then flows generally parallel with the left bank until it passes under the open-bottom arch culvert under 143'd Avenue SE. In 2003 GeoEngineers observed undercutting 1 to 2 feet back into the bank just beyond the downstream end of a masonry block wall. Loose to medium dense, fine to medium sand was observed down to approximately 2 feet below the ground surface behind and adjacent the block wall. In 2007 GeoEngineers (2007a) observed a 500-linear-foot section of May Creek with a combination of erosion (I to 2 feet, left bank) and degraded instream and riparian habitat. GcoEngineers (2003) completed cross-sectional measurements of the site as part of the erosion risk evaluation. Cross-sections indicate that there is considerable overflow capacity along the right side of the stream to provide additional flow capacity during high flow periods. The cross-sections indicated an available channel area of approximately 80 to 90 square feet below the elevation of the top of the masonry block wall. GeoEngineers measured the opening of the open-bottom arch culvert at the western side of the property as approximately a 15-foot span with a 7-foot rise. A rectangular culvert 3 feet wide by 2 feet high, is located through the embankment adjacent to the pipe arch and about 3 feet above the stream bottom. We assume that the rectangular culvert was installed to provide additional capacity for flood flows. We have estimated the maximum opening of the combined culverts as approximately 83 square feet. However, it would require a water depth greater than about 3 to 4 feet above the streambank to utilize this full opening. We estimate only about 45 square feet of opening through the culverts for a water depth at the top of the streambank. Consequently, the culvert opening was determined to be the limiting factor for flood flows through this channel reach. GeoEngineers (2003) determined that there is a significant risk of loss of property and damage to the Madfai residence without the presence of substantial bank protection. The loose, sandy soils comprising the left streambank are very easily eroded. Furthermore, the impingement angle of the primary channel is such that at high flows the unprotected bank will erode rapidly. The residence is less than 25 feet from the streambank and the deck is only 13 feet from the bank. GeoEnginecrs (2003), therefore, determined that the risk to the residence and appurtenant structure is very significant if the masonry block wall were to be removed. This risk is evident in the erosion presently occurring at the downstream end of the masonry blocks. File No. /0791-005-00 December /9, 2008 Page B-7 GEOENGtNEE~ This portion of May Creek was identified in the Action Plan (King County 200 I) as having a stream habitat problem associated with erosion and habitat simplification. This area is also characterized in the Action Plan and the Conditions Report (King County 1995) as being subject to flooding, erosion, degraded stream fish habitat and related problems. The Action Plan characterizes this section of the creek as historically prone to erosion and channel degradation. The GIS database developed by the project team supports these findings. The most prevalent features identified in this segment during the GIS development include erosion and habitat degradation (Figure 6, Appendix A). Erosion problems and recent streambank treatments were observed during recent (2007) site visits. Project Description This project would include the installation of a combination of rock and wood bioengineered structures, and create a high-flow side-channel habitat area along the right bank of May Creek, away from the private property. The project would help stabilize the channel and stabilize sediment transport, and would enhance fish passage, instream habitat and riparian habitat and function. Any non-native plants found would be removed and replaced with native species. This reach of May Creek is presently the most readily accessed by anadromous salmonids. Enhancement of passage and aquatic habitat will be necessary to achieve upstream restoration objectives. Protection of this reach from ongoing erosion and head-cutting is recommended to avoid any potential impacts from upstream activities, including ongoing development and associated changes in the magnitude and volume of runoff. Project Efficacy Based on recent modeling completed for Project 3, the project incorporates a high flow side channel on the right bank for approximately 500 feet upstream of the 143'd crossing. This was modeled by slightly increasing the channel roughness from 0.04 to 0.045 to account for habitat structures and also by altering the right overbank geometry to create a 3-foot deep side channel with a 10-foot bottom width and 3:1 side slopes. The assumed roughness for this channel is 0.045. The side channel was designed to capture flows once the water surface elevation of existing condition situation for I 00 cfs is exceeded. The bottom elevation of the side flow channel was set at 305.4 feet at station 3571. Ineffective flow areas were removed in order to convey water through the high flow channel. The slope of the high flow channel was set at 0.0057 ft/ft which is the slope of the hydraulic grade line for 100 cfs through the reach. The hydraulic results for this project indicate a marginal decrease in maximum velocity (5.75 ft/s to 5.57 ft/s) within the reach for the 2-year (150 cfs) flow rate. Further upstream near the beginning of the side channel the reach average velocity for the 150 cfs flow is reduced from 2.773.9 ft/s to 2.23.4 ft/s. The water surface elevations show mixed results for the side channel project. At the upstream end of the project there is an expected 0.3-2 foot rise over existing conditions for 150 cfs. This rise propagates upstream approximately 300 feet. Within the project reach, it is anticipated that there will be a 0.253-foot drawdown of the water surface profile at 150 cfs. Based on the modeling, there would be no upstream flood mitigation benefits expected from this project. However, there are other benefits that would come from the project including: • approximately 483 feet of restored instream habitat, o 265 feet of protected stream bank from erosion, • creation of a new high-flow channel, and o approximately 14,912 feet of restored riparian area. File No. /079/-005-00 December 19, 2008 Page B-8 GeoENGINE!RS~ I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ' I (") Ii .,, ~ (") w ~ r 5 l ~ I Existing Channel Conditions Conceptual Drawing of Restored Channel.and.Riparian Area ~1---------------------------------------1 g ; w "' GeoENGINEER~ EJrtll Zclt:11ce .,. ~tqJ File No. 10791~005-00 December 19, 2008 .Concepti1al Drawing Project 3 FIGURE 8 3 Page B-9 GeoENGINEERS.i Potential Challenges and Limitations The project would need to be developed and completed on the reach scale and would not be effective if implemented only in part. Coordination of permissions to access the site via several private properties would be required to complete this project as a whole. Landowners must grant permission for these projects to be implemented. Reach and site-specific modeling, design, permitting, and funding of construction would also be required. One residence along this reach of May Creek was constructed within 25 feet of the strcambank, with a deck within 13 feet of the bank. Design and construction of instream habitat, streambank protection, and riparian areas would need to consider this spatial limitation. Work will need to be designed in a manner that does not undermine the 143"' Avenue SE bridge or other areas of May Creek upstream or downstream. Additional regulatory constraints may also be imposed on the proposed project due to the fact that much of May Creek in the May Valley contains critical habitat areas. A critical areas assessment would need to be completed to determine the extent and function of habitat features at the site. Any impacts to stream buffers, wetlands and wetland buffers would need to be mitigated if the project were permitted and implemented. Planning-Level Cost Estimates Estimated Construction Costs: $145,700 (See Appendix C for details). Design, construction observation and permitting costs are not included as these costs can vary significantly. Permitting A portion of the work will be completed below the ordinary high water mark (OHWM), and will result in fill to a critical area. As a result, the following permits and approvals likely will be required: • U.S. Army Corps of Engineers (ACOE) Section 404 • Washington State Department of Fish and Wildlife (WDFW) Hydraulic Project Approval • Washington State Department of Ecology (Ecology) 401 Water Quality Certification • King County Clearing and Grading Permit • SEPA Checklist, with King County lead • King County Critical Areas Review • Compliance with the King County Shoreline Regulations • Tribal and WDFW area biologist consultation File No. /0791-005-00 December 19, 2008 Page B-10 GeoENGINEERS.i I I I I I I I I I I I I I ·I I I I I I I I I I I I I PROJECT 4: HYDRAULIC CONTROL AND HIGH-FLOW CHANNEL Project 4 is another project proposed for implementation in Reach I. This project proposes to create a high-flow channel to improve conveyance through a very low gradient section of May Creek (Figure B-4). This project was identified as a Category C project during the prioritization process. Site Location The proposed Project 4 is located between May Creek RM 4.29 and 4.39 in the NEY. NEY. of Section 3, T.23 N., R. 5 E. and SEY. SEV.. of Section 34, T. 24 N., R. 5 E., W.M. in King County, Washington. The site is at the confluence of May Creek and Tributary 287-D immediately downstream from the 1481h Avenue SE bridge crossing May Creek (Figure 13, Appendix A). The site would include approximately 500 linear feet of May Creek and be completed entirely on private properties located on the right bank (north side) of May Creek near River Mile 4.3. Site Description This section of May Creek is an undersized channel with ongoing loss of channel capacity as the result of sediment deposition and encroachment or reed canarygrass and other riparian vegetation. Based on the Conditions Report (King County 1995), a bedrock hydraulic control is present at the downstream end of this site, serving as the gradient control for RM 4.4 through approximately RM 7.0. Both sides of the creek are degraded wetland habitat. As noted in the Conditions Report (King County 1995), this area was historically a coniferous-forested wetland, but it is used to manage stormwater through the Stonegate Drainfield. This area no longer functions as a forested wetland, but does have some flood attenuation, nutrient assimilation, and habitat value as a degraded wetland. This portion of May Creek was identified in Action Plan (200 I) as having a stream habitat problem. This area is also characterized in the Action Plan (2001) and the conditions report as being subject to flooding, erosion, stream fish habitat, sediment deposition, wetland habitat and related problems due to the low gradient and prevalence of fine sediment. The G!S database developed by the project team supports these findings. The most prevalent features identified in this section during G!S development include channel constriction caused by the encroachment of vegetation and the accumulation of silt (Figure 6, Appendix A). Recd canarygrass (a non-native noxious weed) was observed during site visits to be the primary wetland an riparian habitat feature at the site (GeoEngineers 2007a). This highly invasive non-native species has been known to grow so aggressively that it eliminates competing, native species (Apfelbaum and Sams 1987). It is regarded as significant problem to the conveyance of water because it reduces velocities and can increase siltation (Marten and Heath 1973). Project Description This project would include the installation of a new high-flow channel and restored riparian area along the right bank of May Creek (Figure B-4). The existing channel will not be modified. This project would be designed to help convey water out of the drain-field following periods of prolonged inundation. This project would also be designed to avoid any change in the channel plan-form or gradient. The reported bedrock hydraulic control at RM 4.3 would not be changed. The new high-flow channel would be designed to work in parallel with this existing grade control feature, thereby protecting the channel profile upstream for headcutting, and the downstream channel from excessive runoff and sediment transport. File No. /0791-005-00 December 19, 2008 Page B-11 GEOENGINE£~ .. ! "' 15 ~ ~ I i Existing Channel Conditions '.} ' Conceptual Drawing of Restored Channel and Riparian Area ~ ... ---------------,.------------------1 6 ,, (jj "' GeoENGINEER~ OltD SdfJIU .. Tc;llti:;- File No. /0791-005-00 December 19, 2008 Conceptual Drawing Project 4 FIGURE 8~ Page B-12 GeoENGINURS_@ I I I I I I I I I I I I I I I I I I I I I I I I I I I I Project Efficacy Recent preliminary hydraulic modeling completed by OTAK (2006) as part of this project revealed areas of ineffective flow in this reach of May Creek, suggesting that issues identified in the Action Plan can be expected to persist unless addressed. More recent modeling to evaluate project efficacy assumed that the project would include construction of approximately 500 feet of high flow bypass channel on the right overbank of May Creek approximately 450 feet downstream from the 148'h Street bridge crossing. This portion of May Creek has virtually no slope. The channel slope from the l 48'h Street bridge downstream to the bridge to a survey point just downstream of this project site was estimated as 0.00083 ft/ft. The total drop over the 870-foot reach was calculated to be 0. 72 feet. The constructed side channel was assumed to be two feet deep and set at an elevation of 305 feet with a IO-foot bottom width and 3:1 side slopes. The constructed channel Manning roughness was estimated to be 0.045, the same value as the existing channel roughness for moderate flow regimes (50 to 150 cfs) over the reed canarygrass. Based on modeling results this project would be expected to help mitigate flooding of May Creek in the vicinity of the project. The anticipated drawdown for a discharge of 50 cfs in this reach would be 0.25 feet. This drawdown effect would decrease with increasing discharge at 150 cfs. The flood stage drawdown would be 0.16 feet. Another hydraulic effect of this project would be a decrease in-channel velocity as flood flows would be split between two channels. This would reduce transport capacity in the reach and exacerbate further sedimentation. Channel velocity in the immediate vicinity of the project, at 150 cfs design flow, was predicted to be 1.46 ft/s versus 1.61 ft/s for the existing conditions scenario. The velocity in the right overbank region would be increased. With the construction of the high flow bypass channel modeling predicts an increase in velocity from 0.43 ft/s to I ft/s. Such an increase may assist in mitigating some of the sedimentation issues at this site. Other benefits from the project would include the construction of approximately 479 linear feet of new high-flow channel and I 0, 139 square feet of restored riparian area. Potential Challenges and Limitations Geo Engineers was provided guidance that the reported hydraulic control near RM 4.3 (Action Plan 200 I) should not be disturbed. Work in this area will need to be done in coordination with land managers and landowners. Landowners must grant permission for these projects to be implemented. Contact has been made with two of the landowners, but not with a third private landowner. Permission from all owners will be required to access or construct a project at the lower end of this site. Additional regulatory constraints may also be imposed on the proposed project due to the fact that much of May Creek in the May Valley was historically forested wetland (Conditions Report, King County 1995) or contains other critical areas. A wetland delineation and critical areas assessment would need to be completed to determine the extent and function of wetland and other habitat features at the site. Any impacts to stream buffers, wetlands and wetland buffers would need to be mitigated if the project were permitted and implemented. Planning-Level Cost Estimates Estimated Construction Costs: $43,500 (Sec Appendix C for details). Design, construction observation and pennitting costs are not included as these costs can vary significantly. File No. 1079/-005-00 December 19, 2008 Page B-13 GEOENGINEERS~ Permitting A portion of the work will be completed below the ordinary high water mark (OHWM) and will require placing fill in a critical area. As a result, the following permits and approvals likely will be required: o U.S. Army Corps of Engineers (ACOE) Section 404 o Washington State Department of Fish and Wildlife (WDFW) Hydraulic Project Approval o Washington State Department of Ecology (Ecology) 401 Water Quality Certification o King County Clearing and Grading Permit o SEPA Checklist, with King County lead o King County Critical Areas Review o Compliance with the King County Shoreline Regulations o Tribal and WDFW area biologist consultation File No. 10791-005-00 December 19, 2008 Page B-14 GeoENGIN£!11~ I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I PROJECT 5: WETLAND ENHANCEMENT/REED CANARYGRASS ABATEMENT Project 5 would help improve water conveyance through a very low-gradient, reed canarygrass choked reach of May Creek located below the I 48'h Avenue SE bridge (Figure B-5). Project 5 would work together with Project 4 m Reach I. This project was identified as a Category F project during the prioritization process. Site Location The proposed project site is located between May Creek RM 4.43 and 4.45 in SEY. of Section 34, T. 24 N. R. 5 E., W.M., King County, Washington. The site is located near the confluence of May Creek and Greene's Creek, on the right bank, just downstream from 148'h Avenue SE (Figure 13, Appendix A). Site Description The project proposes to enhance a degraded wetland located on the right bank of May Creek. It is reported in the Conditions Report (King County 1995) that historic Janduse in the area eliminated a conifer and deciduous-based forested wetland previously existing at the site. The wetland remaining at the site is predominantly reed canarygrass and willow with limited other shrubs and forbes (GeoEngineers 2007a). The section of May Creek flowing past the wetland is an undersized channel with ongoing loss of conveyance capacity as the result of sediment deposition and encroachment of reed canarygrass in the channel. This area no longer functions as a forested wetland, but does have some flood attenuation, nutrient assimilation, and habitat value as a degraded wetland (Figure 6, Appendix A). Project Description This project would include removing reed canarygrass from the stream channel and surrounding area and planting native wetland and riparian species to help restore a forested wetland along the right bank of May Creek (Figure B-5). The existing channel would not be modified at the site as part of this project. This project would be designed to help assimilate flood water, assimilate nutrients, and provide significantly improved riparian and wetland habitat. Fish passage will be improved by reducing the amount of reed canarygrass encroaching on the stream channel. Project Efficacy A hydraulic model was used to evaluate the efficacy of Project 5, assuming a !-foot deep swale approximately 200 feet wide and 500 feet Jong along the longitudinal direction of the channel. Such a swale would result in an approximate 2.5 acre area. Flow through this area would be considered ineffective until the overbank stage was exceeded. At the overbank flow point, there would be skimming flow into the swale above the wetland stage. The Santa Barbara Unit Hydrograph method was utilized to account for storm runoff changes due to the land use change. The runoff curve number was changed from 85 to 80 to account for the land use change. This curve number adjustment was made assuming a hydrologic type C soil and converting the land use from meadow/pasture to young second growth or brush forest land (King County 1992). It was anticipated that such a land use change would reduce flood runoff from this 2.52-acre site by approximately 54 percent for a 2-year, 24-hour precipitation event of 2 inches. The peak runoff rate would be decreased from 0.26 cfs to 0.12 cfs. This would help attenuate downstream flood flows. According to the HEC-RAS analysis, this project would also help to lower local flooding levels by 0.23 feet for the 150 cfs flow. Reach average channel velocity would decrease from 1.67 ft/s to 1.51 ft/s for the 150 cfs flow rate within the reach due to the forest wetland detention of flood flows. File No. 10791-005-00 December 19, 2008 Page 8-15 GEOENGINEERS_B i t:; .,, i ;g e i !t l5 ~ ~ ~ l ~ ! ExlsUng CondlUons ·1.,-,,,,. ,., ·conceptual Drawing of Restored weuand.and.reed canarygrass abatement project 51----------------------------------1 s i GeoENGINEER~ E.trUI Sdteca • Tectnalon File No. /079/-005-00 December I 9, 2008 Conceptual Drawing Profei:t 5 FIGURE 0-5 Page B-16 GEOENGINEER!.@ I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Model results indicated that the project would have no effect on upstream flood levels. The project, however, would have other benefits including the enhancement of 20,789 square feet of riparian habitat, as well as enhancement of25,l23 square feet of wetland and 85,080 square feet of wetland buffer habitat. Potential Challenges and Limitations GeoEngineers was provided guidance that the reported hydraulic control near RM 4.3 (Action Plan 200 I) should not be disturbed. Work in this area will need to be done in coordination with land managers and owners. Landowners must grant permission for these projects to be implemented. Over I acre of area would be disturbed, requiring additional permitting and regulatory agency coordination steps. Additional regulatory constraints may also be imposed on the proposed project due to the fact that much of May Creek in the May Valley was historically forested wetland (Conditions Report, King County 1995) or contains other critical areas. A wetland delineation and critical areas assessment would need to be completed to determine the extent and function of wetland and other habitat features at the site. Any impacts to stream buffers, wetlands and wetland buffers would need to be mitigated if the project were permitted and implemented. Planning-Level Cost Estimates Estimated Construction Costs: $69,000 (See Appendix C for details). Design, construction observation and pennitting costs are not included as these costs can vary significantly. Permitting A portion of the work will be completed below the ordinary high water mark (OHWM}, and will require placing fill in a critical area. As a result, the following permits and approvals likely will be required: • U.S. Army Corps of Engineers (ACOE) Section 404 • Washington State Department of Fish and Wildlife (WDFW) Hydraulic Project Approval o Washington State Department of Ecology (Ecology) 401 Water Quality Certification • King County Clearing and Grading Permit • SEPA Checklist, with King County lead • King County Critical Areas Review • Compliance with the King County Shoreline Regulations • Tribal and WDFW area biologist consultation This project would likely disturb over l acre of ground. This would, therefore, create additional permitting steps including ACOE Section 404 project-specific permitting and requirements under Ecology's National Pollutant Discharge Elimination System (NPDES), securing a Construction Stormwater General Penni!. File No. /079/-005-00 December 19, 2008 Page B-17 GeoENGINEERS.i PROJECT 6: GREENE'S CREEK CONFLUENCE PROJECT· POND/WETLAND ENHANCEMENT Project 6 proposes to help address flooding in the project vicinity by improving wetland and riparian habitat in this reed canarygrass choked reach of the May Valley located downstream from the 1481 h Avenue SE bridge (Figure 8-6). Project 6 would complement the projected effects of Project 5 in this area. Project 6 was identified as a Category F project during the prioritization process. Site Location The proposed project site is located between May Creek RM 4.33-4.45, in SEY. of Section 34, T. 24 N., R. 5 E., W.M. in King County, WA. The site is located upstream from the confluence of May Creek and Greene's Creek, on the left bank, just downstream from 148th Avenue SE (Figure 13, Appendix A). Site Description The site is a degraded wetland on the left bank of May Creek. It is reported in the Conditions Report (King County 1995) that landuse in the area degraded the conifer and deciduous-based forested wetland that likely previously existed at the site. The present wetland is predominantly reed canarygrass and willow, with limited other shrubs and forbes. The section of May Creek adjacent this wetland is an undersized channel with ongoing loss of channel capacity as the result of sediment deposition and encroachment of reed canarygrass and other riparian vegetation (Figure 6, Appendix A). This area no longer functions as a forested wetland, but it does have some flood attenuation, nutrient assimilation, and habitat value as a degraded wetland. The abundance of vegetation and deposition of silt in this area has eliminated a clear confluence area of May Creek and Greene's Creek. Project Description This project would require the removal ofreed canarygrass from the Greene's Creek stream channel and surrounding area and the planting of native wetland and riparian vegetation to help restore a forested wetland along the left bank of May Creek near the Greene's Creek confluence area (Figure 8-6). The project would restore connectivity between May Creek and Green's Creek by creating a new channel through a constructed wetland and a new May Creek confluence area. It may also be possible to route Green's Creek through the existing storm water retention pond located southwest of the proposed site, to further enhance retention capabilities of this project. The existing May Creek channel would not be modified. This project would be designed with the intent to better assimilate flood water and nutrients in both May Creek and Greene's Creek. The project would also be designed to help maintain a free-flowing stream channel, and to significantly improved riparian and wetland habitat. Another purpose of the project would be to improve fish passage by reducing the amount of silt and vegetation clogging the channel. Project Efficacy The potential hydraulic effects of the project were modeled by simulating the excavation a I -foot deep swale using the approximate dimensions of the basin to be 210 feet in width and 650 feet along the longitudinal direction of the stream, resulting in 3.27 acres of project site. Modeling results indicated that local flood levels would drop 0.64 feet for the 2-yr flood and velocities would decrease from an average channel velocity of 1.61 ft/s to 0.76 ft/s for the 150 cfs flow, as flood flows are dissipated over the forested wetland. The flow area would be considered ineffective flow until the overbank stage was exceeded. At this point there would be skimming flow above the wetland stage. File No. 1079/-005-00 December 19, 2008 Page B-18 GEOENGINEER~ I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I "' i ,I: : l'i ~ ~ I ;; Existing Conditions (, Com;~ptual Drawing of Restored Wetland imd reed canarygrass abatement project 1:.;·1--------------r-----------------1 ;; s "' GeoENGINEER~ brttl sa.:nce • Tccmmtou File No. /079/-005-00 December 19, 200R Concaptual Drawing Project 6 FIGURE.BG Page B-19 GEOENGINEERS ...0 The Santa Barbara Unit Hydrograph method was utilized to account for storm runoff changes due to the land use change. The runoff curve number was changed from 85 to 80 to account for the land use change. This curve number adjustment was made assuming a hydrologic type C soil and converting the land use from meadow/pasture to young second growth or brush forest land (King County 1992). It is anticipated that this land use change would reduce flood runoff from this 3.27-acre site by approximately 54 percent for a 2-year, 24-hour precipitation event of 2 inches. The peak runoff rate would be decreased from 0.34 cfs to 0.18 cfs. This would help attenuate downstream flood flows. The project would also provide over 140,000 square feet of combined created wetland and enhanced wetland buffer. Potential Challenges and Limitations The reported existing hydraulic control should not be disturbed. Work in this area will need to be coordinated with the land owners and managers. Landowners must grant permission for these projects to be implemented. The project would need to be designed to work in concert with an existing stormwater pond, located to the west of Green's Creek. Over l acre of area would be disturbed, requiring additional permitting and regulatory agency coordination steps. Additional regulatory constraints may also be imposed on the proposed project due to the fact that much of May Creek in the May Valley was historically forested wetland (Conditions Report, King County 1995) or contains other critical areas. A wetland delineation and critical areas assessment would need to be completed to determine the extent and function of wetland and other habitat features at the site. Any impacts to stream buffers, wetlands and wetland buffers would need to be mitigated if the project were permitted and implemented. Planning-Leve/ Cost Estimates Estimated Construction Costs: $59,800 (See Appendix C for details). Design, construction observation and permitting costs are not included as these costs can vary significantly. Permitting A portion of the work will be completed below the ordinary high water mark (OHWM), and will require placing fill in a critical area. As a result, the following permits and approvals likely will be required: o U.S. Army Corps of Engineers (ACOE) Section 404 o Washington State Department of Fish and Wildlife (WDFW) Hydraulic Project Approval o Washington State Department of Ecology (Ecology) 40 l Water Quality Certification o King County Clearing and Grading Permit o SEPA Checklist, with King County lead o King County Critical Areas Review • Compliance with the King County Shoreline Regulations o Tribal and WDFW area biologist consultation This project is expected to disturb over l acre of ground. As a result, additional permitting steps will be required, including ACOE Section 404 project-specific permitting and requirements under Ecology's National Pollutant Discharge Elimination System (NPDES), securing a Construction Stormwater General Permit. File No. /079/-005-00 December 19, 2008 Page B-20 GEOENGIN!!~ Gil ll!I I I I I I I • I I I I I I I I I I I I I I I I I I I PROJECT 7: 148TH AVENUE SE HIGH-FLOW CONVEYANCE PROJECT Project 7 was developed in an effort to alleviate flooding over 148'" Avenue SE and reduce backwater effects that may be worsening flooding upstream. This project proposes to improve conveyance under 148'h Avenue SE utilizing a high-flow channel and culvert on the right (north) bank of May Creek (Figure B-7). This project was identified as a Category A project during the prioritization process. Site Location The proposed project site is located between May Creek, RM 4.39 to 4.55 in the SEY. of Section 34 and the SWY. of Section 35, T. 24 N., R. 5 E., W.M., in King County, Washington. The site is at 148'h Avenue SE, and extends approximately 500 feet upstream and downstream of 148'h Avenue SE (Figure 14, Appendix A). Site Description The proposed project located at 148th Avenue SE and traverses degraded wetlands located on the right (north) bank of May Creek, both upstream and downstream of 148'h Avenue SE. The Conditions Report (King County {1995) indicates that landuse changes in the area resulted in degradation of a coniferous and deciduous-based forested wetland likely previously present at the site. The present-day wetland is predominantly composed of reed canarygrass and willow. This section of May Creek is an undersized channel with ongoing loss of channel capacity as the result of sediment deposition and encroachment of reed canarygrass (Figure 6, Appendix A). This area no longer functions as a forested wetland, but it does have some flood attenuation, nutrient assimilation, and habitat value as a degraded wetland. The area frequently floods (Figure B-7). Project Description This project would primarily address flooding by creating a high-flow channel and culvert through 148'h Avenue SE north of the existing May Creek bridge crossing (Figure B-7). The project would also provide habitat benefits creation of off-channel habitat for fish, and creation of riparian habitat adjacent to the created high-flow channel. The new high-flow channel project would not alter the existing bridge crossing or the existing May Creek channel alignment. This project would help reduce flooding, sediment deposition, and loss of channel capacity upstream from 148'" Avenue SE. Project Efficacy HEC-RAS multiple opening analysis was utilized to evaluate the effectiveness of the bypass channel proposed by this project. A IO-foot-wide by 4-foot-tall box culvert was added on the right (north) bank and was assumed to have a Manning "n" of 0.04 for the stream simulation culvert. The culvert invert elevation was set 306.5 feet at the upstream side of the crossing and incorporates a 0.2-foot drop across the crossing. The modeling results suggest that the bypass channel would increase upstream channel velocities from I. 73 ft/s to 2.4 ft/s for the 2-year, 150 cfs event. This should help to alleviate some of the sedimentation problems in this area. At the downstream end of the 148'h crossing this project would reduce in-channel velocities because of the flow split. For the 2-year event, the velocity is reduced from 5.49 ft/s to 3.84 ft/s. The upstream water surface elevations would be reduced locally. The magnitude and upstream extent of the flood stage reduction would increase with increasing discharge. For example, at 50 cfs, models predicted a water surface drop of 0.1 foot, extending approximately 300 feet upstream. At 150 cfs, the water surface was predicted to drop 0.5 feet and extend 600 feet upstream. At 300 cfs, approximately a 5-year event on this reach of May Creek, the hydraulic effects are stronger and flood stage is reduced approximately 0.5 feet and the flood reduction was projected to extend approximately 1,000 feet upstream. File No. /079/-005-00 December 19, 2008 Page B-21 GEOENGINEERS_.@ i l ., s ~ I ''.J"'"" .. · 4 .... ·.•·i··· .,, ~ ·' 14' ,/11, .. . ~.-... Existing Conditions i;; 151---------------------------------t B ~ "' File No. 10791-005-00 December 19, 2008 Page B-22 Conceptual Drawing Project 7 FIGURE 8.7 GeoENGINEER~ I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Potential Challenges and Limitations Work in this area would need to be well coordinated with traffic management to mm1m1ze traffic congestion on or close to 1481 h Avenue SE. This road is heavily used and long-term closure would not be well received by residents or others that frequent the area. King County may already be considering bridge or road improvements in the area. Therefore, any work completed as part of this project should be coordinated with any 1481 h Avenue SE bridge and road maintenance to be completed by King County. Coordination with county roads staff will be required to avoid duplication of effort, and to minimize any potential traffic-flow impacts. Additional regulatory constraints may also be imposed on the proposed project due to the fact that much of May Creek in the May Valley was historically forested wetland (Conditions Report, King County 1995) or contains other critical areas. A wetland delineation and critical areas assessment would need to be completed to determine the extent and function of wetland and other habitat features at the site. Any impacts to stream buffers, wetlands and wetland buffers would need to be mitigated if the project were permitted and implemented. Conceptual Designs and Planning-Level Cost Estimates Estimated Construction Costs: $243,500 (See Appendix C for details). Design, construction observation and permitting costs are not included as these costs can vary significantly. Permitting A portion of the work will be completed below the ordinary high water mark (OHWM), and will require placing fill in a critical area. As a result, the following permits and approvals likely will be required: • U.S. Army Corps of Engineers (ACOE) Section 404 • Washington State Department of Fish and Wildlife (WDFW) Hydraulic Project Approval • Washington State Department of Ecology (Ecology) 401 Water Quality Certification • King County Clearing and Grading Permit • SEPA Checklist, with King County lead • King County Critical Areas Review • Compliance with the King County Shoreline Regulations • Tribal and WDFW area biologist consultation This project also would be expected to disturb over I acre of ground. As a result, additional permitting steps will be required, including ACOE Section 404 project-specific permitting and requirements under Ecology's National Pollutant Discharge Elimination System (NPDES) for securing a Construction Stormwater General Penni!. File No. 1079/-005-00 Decemher 19, 2008 Page B-13 GEOENGINEERS.i PROJECT 8: WETLAND ENHANCEMENT/REED CANARYGRASS ABATEMENT PROJECT Project 8 proposes to help address flooding in the project vicinity by improving wetland and riparian habitat in this reed canarygrass choked reach of the May Valley above the 148'h Avenue SE bridge (Figure B-8). Project 8 may complement the projected effects of Projects 4 and 7 if also implemented. This project was identified as a Category N project during the prioritization process. Site Location The proposed site is located between RM 4.45 to 4.57 of May Creek, being within the SWY. of Section 35, T. 24 N., R. 5 E., W.M., in King County, Washington. The site is upstream of 148 1h Avenue SE on the right and left banks of May Creek (Figure 14, Appendix A). Site Description The site is currently a degraded wetland on both banks of May Creek. Based on the Current Conditions Report, landuse in the area eliminated the coniferous and deciduous-based forested wetland likely historically present at the site. The wetland presently is predominantly reed canarygrass and willow, with few other shrubs and forbes. This section of May Creek is an undersized channel with ongoing loss of channel capacity as the result of sediment deposition and encroachment of reed canarygrass and other riparian shrubs (Figure 7, Appendix A). This area no longer functions as a forested wetland, but does have some flood attenuation, nutrient assimilation, and habitat value as a degraded wetland. The area frequently floods. Project Description This project would primarily focus on removing reed canarygrass and planting native wetland species in an attempt to restore the forested wetland and buffer adjacent to May Creek (Figure B-8). Removal of the reed canarygrass would reduce flooding and sediment deposition by allowing for better conveyance of water; improve water quality; and improve riparian and wetland habitat at the site. By 1ninimizing vegetative encroachment on the stream channel, this project would also improve fish passage to other high fish use areas upstream in May Creek. The existing May Creek channel would not be modified. This project would be designed to better assimilate flood water and sediment approaching the l 48'h Avenue SE and to work in conjunction with Project 7 and IPR I. Project Efficacy The effectiveness of Project 8 was evaluated using approximate dimensions of the wetland depression as 370 feet in width and 260 feet along the longitudinal direction of the stream. This complex spans both sides of the stream and the resulting average flow path was estimated as approximately 200 feet. The total area of the wetland complex was estimated to be 1.6 acres. The flow area was considered to be ineffective flow until the overbank stage was exceeded. At this point there would be skimming flow above the wetland bottom. The Santa Barbara Unit Hydrograph method was utilized to account for storm runoff changes due to the land use change. The runoff curve number was changed from 85 to 80 to account for the land use change. This curve number adjustment was made assuming a hydrologic type C soil and converting the land use from meadow/pasture to young second growth or brush forest land (King County 1992). Results of hydraulic modeling analyses suggest that the anticipated land use change would reduce flood runoff from this 1.61-acre site by approximately 54 percent for a 2-year, 24-hour precipitation event of 2 inches. The peak runoff rate would be decreased from 0.167 cfs to 0.091 cfs. This would help attenuate downstream flood flows. File No. 10791-005-00 December 19, 2008 Page B-24 GEOENGINEERS_all I I I I I I I I I I I I I I I D I I I I I I I I I I I I I I I I I I I Conceptual Drawing.of Restored Wetland and reed canarygrass GeoENGINEER~ E.JJ'UI Scl!ntt + Ttcfflloo , Fife No. 1079/-005-00 December 19, 2008 abatement pro]ei;t · · .Conceptual Drawln~ Protect 8 FIGURE 8-8 Page B-25 GeoENGINEERS...@ This project was modeled by excavating a swale with a bottom depth that is one foot lower than the adjacent overbank elevation for nearby May Valley survey transects. The swale was assumed to have 20: I side slopes, a width of 50 feet on the left bank side and 185 feet on the right bank side. Modeling results indicated that this project would slightly increase flood stage elevations for the 2-year event locally on the order of 0.1 feet. Modeled velocities decreased upstream of the detention feature (2.1 ft/s (existing) vs. 2.0 ft/s (proposed)) and increased in the vicinity of the detention feature (1.5 ft/s for existing conditions vs. 1.99 ft/s for the proposed project conditions. The reach average velocity increases minimally from 1.9 ft/s to 1.96 ft/s. Based on modeling results, the proposed project would provide better velocity continuity within the reach. The project would also provide about 56,000 square feet of enhanced wetland, 6,300 square feet of created wetland and 64,000 square feet of enhanced wetland buffer. Potential Challenges and Limitations The landowner has not been contacted for permission to further develop this project. Landuse at the site is presently open-space wetland. The project proposes to restore forested wetland and buffer over the majority of the parcel, possibly precluding other uses. Alternative designs should be developed to accommodate landuse plans of the landowner/manager. Landowners must grant permission for these projects to be implemented. It is likely that over I acre of area would be disturbed, requiring additional permitting and regulatory agency coordination steps. Additional regulatory constraints may also be imposed on the proposed project due to the fact that much of May Creek in the May Valley was historically forested wetland (Conditions Report, King County 1995) or contains other critical areas. A wetland delineation and critical areas assessment would need to be completed to determine the extent and function of wetland and other habitat features at the site. Any impacts to stream buffers, wetlands and wetland buffers would need to be mitigated if the project were pennitted and implemented. Conceptual Designs and Planning-Level Cost Estimates Estimated Construction Costs: $148,300 (See Appendix C for details). Design, construction observation and permitting costs are not included as these costs can vary significantly. Permitting A portion of the work will be completed below the ordinary high water mark (OHWM), and will require placing fill or working in a critical area. As a result, the following permits and approvals likely will be required: • U.S. Army Corps of Engineers (ACOE) Section 404 • Washington State Department of Fish and Wildlife (WDFW) Hydraulic Project Approval o Washington State Department of Ecology (Ecology) 401 Water Quality Certification • King County Clearing and Grading Permit • SEPA Checklist, with King County lead • King County Critical Areas Review • Compliance with the King County Shoreline Regulations • Tribal and WDFW area biologist consultation This project is expected to disturb over I acre of ground. As a result, additional permitting steps may be required, including ACOE Section 404 project-specific permitting and requirements under Ecology's National Pollutant Discharge Elimination System (NPDES) to secure a Construction Stormwater General Pennit. File No. 1079 J .005~00 December 19, 2008 Page B-26 GEOENGINEER~ I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I PROJECT 9: LONGMARSH CREEK ENHANCEMENT PROJECT Project 9 proposes to help address flooding in the project vicinity by reducing sediment transport for Longmarsh Creek into May Creek. This would be accomplished by improving instream and riparian habitat conditions in lower Longmarsh Creek (Figure B-9). This project was identified as a Category K project during the prioritization process. Site Location The proposed Project 9 is located at the May Creek -Long Marsh Creek confluence area near RM 4.6 in the SWY. of Section 35, T. 24 N., R. 5 E., W.M. in King County, Washington (Figure 14, Appendix A). The site includes the lowermost 500 feet of Long Marsh Creek up to the SE May Valley Road culvert (Long Marsh Creek RM Oto 0.1 ). Site Description The site includes one of the few open, free-flowing, gravel-bottomed segments of May Creek in the May Valley subarea. The gravel source is Long Marsh Creek, flowing into May Creek from the north (right) bank at approximately RM 4.6. Riparian and instream habitat in May Creek and Long Marsh Creek have been degraded. There is very little riparian vegetation between RM O and 0.1 on Long Marsh Creek, below the culvert under the SE May Valley Road. Long Marsh Creek is eroding, often contributing large amounts of sediment to May Creek (Figure 7, Appendix A). Mature trees growing along May Creek provide shade and help maintain the free-flowing channel in this reach. Project Description This project would install a variety ofbioengineered structures, meanders and a pool in Longmarsh Creek to move toward a more stable geomorphic regime in this tributary stream, between RM O to RM 0.1. These added features would enhance instream and riparian habitat throughout Long Marsh Creek. Water quality should also improve as the habitat is restored, through the reduction of total suspended solids, including a reduction in animal waste. In addition to improving habitat in this tributary stream, the project would also help to maintain a free-flowing stream channel in May Creek. The free-flowing channel would result in a reduced sediment load to May Creek at the confluence and, as a result, reduce upstream flooding. Project Efficacy This project is very conceptual in nature. Site specific survey work and hydraulic modeling would need to be completed to estimate the potential project benefits. Qualitatively speaking, reducing sediment loading from this unstable tributary would be expected to help reduce local flooding issues and improve downstream habitat. Further investigation into this project would be worthwhile. The project would also create about 541 linear feet of new channel, I ,400 square feet of new pool habitat and 9,200 square feet of restored riparian habitat. Potential Challenges and Limitations This project would occur on lands owned by two private parties. The land is being actively used for residential and livestock purposes. Landowners must grant permission for these projects to be implemented. Some of the area used by livestock would need to be converted to strcambed and riparian area or at least fence to restrict livestock use for this project to succeed. It is unknown if enhancement of this tributary would be of interest to landowners. A number of private properties have been up for sale in this area. There are uncertainties about landowner contact information at the time this report was written. File No. /079/-005-00 Decemher /9, 2008 Page B-27 GEOENGINEER~ Existing Channel Conditions w J :g i Q.. .: 0 " ll ~ Ii I ;;; \. l . J ; ,, ... . ' .,., ~-.;, ",,. -. Conceptual Drawing of Restored Charmel and Riparian Area :;;1-----------------------------1 ,, C> ,, {a "' GeoENGINEER~ lart!I Stitn« + Ttth4cl!Qf, File No. /0791-005-00 December 19, 2008 Conceptuol Drowing Project 9 HGUKt H.S Page 8-18 GEOENGINHR!.@ I I I I I I I I I I I I I I I I I I m I I I I I I I I I I I I I I I I I I I Additional regulatory constraints may also be imposed on the proposed project due to the fact that much of May Creek in the May Valley was historically forested wetland (Conditions Report, King County 1995) or contains other critical areas. A wetland delineation and critical areas assessment would need to be completed to determine the extent and function of wetland and other habitat features at the site. Any impacts to stream buffers, wetlands and wetland buffers would need to be mitigated if the project were permitted and implemented. Planning-Level Cost Estimates Estimated Construction Costs: $69,900 (See Appendix C for details). Design, construction observation and permitting costs are not included as these costs can vary significantly. Permitting A portion of the work will be completed below the ordinary high water mark (OHWM), and will require placing fill to a critical area. As a result, the following permits and approvals likely will be required: • U.S. Army Corps of Engineers (ACOE) Section 404 o Washington State Department of Fish and Wildlife (WDFW) Hydraulic Project Approval • Washington State Department of Ecology (Ecology) 401 Water Quality Certification o King County Clearing and Grading Permit • SEPA Checklist, with King County lead • King County Critical Areas Review o Compliance with the King County Shoreline Regulations o Tribal and WDFW area biologist consultation File No. /079/~005-00 December 19, 2008 Page B-29 GeoENGINEERS_g PROJECT 10: TSEGAY WETLAND ENHANCEMENT/REED CANARYGRASS ABATEMENT Project 10 proposes to help address flooding in the project vicinity by improving wetland and riparian habitat in this reed canarygrass-choked reach of the May Valley (Figure B-10). Project IO may complement the projected effects of Project 11 and IFP I, if also implemented. This project was identified as a Category G project during the prioritization process. Site Location Proposed Project 10 is located on the left (south) bank of May Creek near RM 4.7, approximately 500 feet upstream from the confluence of May Creek and Long Marsh Creek. The project site is located in the west Y, of Section 2, T 23 N., R 5 E.,W.M. in King County, Washington (Figure 14, Appendix A). The property is currently owned by the Tsegay's. Site Description The site is a degraded wetland and is currently used as horse pasture. Based on the Conditions Report, landuse in the area eliminated the conifer and deciduous-based forested wetland likely historically present at the site. The remnant wetland (Figure 5, Appendix A) is predominantly reed canarygrass and willow, with several other shrubs and forbes. The section of May Creek adjacent this site is an undersized channel with ongoing loss of channel capacity as the result of sediment deposition and encroachment of reed canarygrass and other riparian vegetation. This area no longer functions as a forested wetland, but does have some flood attenuation, nutrient assimilation, and habitat value as a degraded wetland. The area frequently floods (Figure 7, Appendix A). Project Description This project would primarily focus on removing reed canarygrass and restoring native wetland and riparian species in an attempt to restore forested wetland and wetland buffer within an area of approximately l to 1.5 acres adjacent to the left (south) bank of May Creek. Removal of the reed canarygrass and other design features are intended to help the area better assimilate flood water and nutrients in both May Creek and from upland sources. The project also intends to help reduce flooding and sediment deposition, improve water quality; and improve riparian and wetland habitat at the site. The removal of canarygrass that has encroached on May Creek also would improve fish passage to other high fish use areas upstream in May Creek. A wetland detention area is proposed for the left overbank region with the following approximate dimensions: 150 feet in width and 320 feet long along the longitudinal direction of the stream The existing May Creek channel would not be modified. File No. 10791-005-00 December 19, 2008 Page 8-30 GEOfNGINEERS_a} I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I , )·. " \: . r·· ",,._._ ... ,.{ ,C ; ;t' . -,j I " . ' ' \ ', ' • I i .• l',[£! fifi'Ilm ' -i> '.£ ~ .I ~ , ... ' ' \ lllillWl ' ' ' 1111 ; ,. I d', ....... , ... ~ .. _ l"'·)~, • /, ":--·-,... ' ~ ~) ,, ,tw Existing Conditions ' ... Conceptual Drawing of Restored Wetland and reed canill'Ygrass · · · · abatement project · · · GeoENGINEER~ l.lltlt k.irnta' + lmfflQIOI]' File No. 10791+005-00 December 19, 2008 Page B-31 Cont:11ptual Drawing Project 10 FIGURE B,10 GEOENGINEE~ Project Efficacy The effectiveness of Project IO was modeled assuming that a 1.2-acre wetland complex would be created. Similar assumptions were utilized as for other wetland modeling scenarios described for earlier projects. This project was predicted to reduce the storm runoff from this area from 0.13 cfs to 0.056 cfs, a 56 percent reduction for the 2-year event. Results of the modeling indicate that this project, in combination with Project 11, would lower water surface elevation within the reach for the 2-year event of 150 cfs. The water surface would be lowered by approximately 0.1 foot. This project would also help to increase channel velocities along the reach. In-channel velocities were predicted to marginally increase as a result of the project. For example, in-channel velocities at one modeling point were predicted to increase from 1.48 ft/s to 1.61 ft/s, a nine percent relative increase. These increases in channel velocity may mitigate some of the sedimentation problems in the area. Based on modeling results, Project 10 in combination with Project 11 is projected to reduce flooding, increase channel velocities, and decrease sedimentation in this reach of May Creek. Project IO would also create about 8,000 square feet of wetland and enhance approximately 45,500 square feet of wetland buffer. Potential Challenges and Limitations This project would occur on lands owned by two private parties. The land is being actively used for residential and livestock purposes. Landowners must grant permission for these projects to be implemented. Some of the area used by livestock would need to be converted to enhanced wetland and riparian area or at least fenced to restrict livestock use for this project to succeed. It is unknown if these actions would be of interest to landowners. It is likely that over I acre of area would be disturbed, requiring additional permitting and regulatory agency coordination steps. Additional regulatory constraints may also be imposed on the proposed project due to the fact that much of May Creek in the May Valley was historically forested wetland (Conditions Report, King County 1995) or contains other critical areas. A wetland delineation and critical areas assessment would need to be completed to determine the extent and function of wetland and other habitat features at the site. Any impacts to stream buffers, wetlands and wetland buffers would need to be mitigated if the project were permitted and implemented. Planning-Level Cost Estimates Estimated Construction Costs: $104,500 (See Appendix C for details). Design, construction observation and permitting costs are not included as these costs can vary significantly. Permitting A portion of the work will be completed below the ordinary high water mark (OHWM), and will require placement of fill in a critical area, the following permits and approvals likely will be required: • U.S. Anny Corps of Engineers (ACOE) Section 404 • Washington State Department of Fish and Wildlife (WDFW) Hydraulic Project Approval • Washington State Department of Ecology (Ecology) 40 I Water Quality Certification o King County Clearing and Grading Permit o SEPA Checklist, with King County lead • King County Critical Areas Review o Compliance with the King County Shoreline Regulations o Tribal and WDFW area biologist consultation File No. /079/-005-00 December I 9, 2008 Page B-32 GeoENGINEER~ I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I This project is expected to disturb over I acre of ground. As a result, additional permitting steps will be required, including ACOE Section 404 project-specific pcnnitting and requirements under Ecology's National Pollutant Discharge Elimination System (NPDES) to secure a Construction Stormwater General Penni!. File No. /079/-005-00 Decemher I 9, 2008 Page 8-33 GEOENGINEEIIS_yi' PROJECT 11: COLASURDO WETLAND ENHANCEMENT/REED CANARYGRASS ABATEMENT Project 11 is primarily a reed canarygrass abatement and native plant restoration project, similar to several other projects being proposed in this CRP (Figure 8-11 ). Dense stands of reed canarygrass monocultures have developed throughout the valley, and are contributing to flood, silt, fish passage, fish habitat, riparian and wetland function and related problems. This project was identified as a Category E project during the prioritization process. This project was selected as a pilot project to be completed in 2007 in an attempt to begin mitigating flooding and address some of the negative effects of the highly invasive weed, reed canarygrass. This project was presented in a Pre-Design Report (GeoEngineers, 2007). It is one of four projects identified as potential early-implementation projects proposed for implementation in 2007 and 2008. As a result, a more detailed overview is provided for this project, as compared to the majority of the other projects in this Appendix. The detail is provided for this project, based on the additional work that the project team completed during the predesign process in early 2007. Please note that the project was in permitting, with available funding in the spring of 2007, and ready for implementation but construction has not begun because of site access challenges. Site Location The proposed project is located between May Creek RM 4.65 and 4.90, in the west Y, of Section 2, T. 23 N., R. 5 E., W.M. in King County, Washington (Figure 14, Appendix A). The site extends between approximately 500 feet and 2000 feet upstream from the confluence of May Creek and Long Marsh Creek to a point approximately 250 feet upstream from Indian Meadow Creek. Site Description The site is located in a degraded wetland on the left and right bank of May Creek, presently being used as horse pasture. Based on the Conditions Report (1995), landuse activities in the area eliminated the conifer and deciduous-based forested wetland likely historically present at the site. The Report also considers May Creek to be an "underfit" stream flowing through an agricultural and livestock-raising region. May Creek throughout the May Valley was channelized throughout the May Valley and re- aligned sometime between 19 l O and 1936 from its previous condition as a meandering, low-gradient stream (~ 0.2 percent slope) to its contemporary location which serves as a property boundary between valley landowners. This area of May Creek is characterized in the Action Plan (2001) and the conditions report as being subject to flooding, erosion, stream fish habitat, sediment deposition, wetland habitat and related problems (Figure 7, Appendix A). The existing wetland is predominantly pasture grass with some reed canarygrass and willow immediately adjacent the creek. May Creek adjacent to the site flows in a low-gradient, undersized straight channel that continues to lose channel capacity because of sediment deposition and encroachment of reed canarygrass and other riparian vegetation. This area no longer functions as a forested wetland, but does have some flood attenuation, nutrient assimilation, and habitat value as a degraded wetland. This area frequently floods. The channel has little habitat complexity, in-channel wood, or variability in substrate composition. The GIS database developed by the project team supports these findings. The most prevalent features in this stream reach, identified using the GIS database, included channel constriction caused by the encroachment of vegetation and the accumulation of silt. Reed canarygrass was observed to be the primary riparian vegetation, and headwaters erosion problems were observed during 2006 and 2007 site visits (Figure 7, Appendix A). File No. 10791-005-00 December 19, 2008 Page 8-34 GEOENGINEIR~ I I I I I I I I I I I I I I I I I It I I I I I I I I I I I I I I I I I I I I ;'i; l 15 ~ ~ 1 j 9 .. Existing Conditions Conceptual Dr11w1ng of ~lparian area enhancement and reed caharygniss abatement project · ~---------------------------------4 15 ,.. Iii "' GeoENGINEER~ hrtll Scitlltl • lttlma}ffl File No. 1079/-005-00 December 19. 2008 Conceptual Drawin!I Proieci 11 FIGURE 8-11 Page B-35 GeoENGIN!ERS g Project Description Project 11 would primarily attempt to restore riparian forested area along both banks of May Creek with a buffer width of at least 25 feet. The existing May Creek channel would not be modified. This project will reduce the levels of sediment deposition and vegetation constraining flow in this already undersized channel. The project will help to maintain a free-flowing stream channel by concentrating velocities within the channel margin rather that dissipating energy across the floodplain. The project would significantly improve riparian and wetland habitat and assist with fish passage through the area presently impaired by sediment and reed canarygrass. Improved passage through this reach would allow access upstream in May Creek where there are locally significant anadromous fish resource areas. This project would use a combination of mechanical treatment and hand-removal of reed canarygrass shoots and rhizomes coupled with the high-density planting of native shrubs and trees. Those portions of May Creek where both banks of the creek could be treated would be prioritized. At least 20 feet of buffer zone would be heavily replanted with native trees and shrubs. Browse protection will be an important part of this project, both to avoid the potential effects from pasture animals as well as from beavers known to inhabit the valley. The removal of reed canarygrass, restoration of native vegetation and the combined effect of creating a free-flowing stream channel are expected to have a variety of benefits to the project area. These anticipated benefits include: • Floodwaters are anticipated to move off the floodplain at a higher rate, thereby making it possible for pasture land to dry out at a faster rate, • Reduction in accumulation of silt, including in-channel and tributary confluence areas, from pasture areas and upstream sources, • Increasing fish migration and habitat use by introducing shading with native plants and by reducing the degree of channel impingement caused by the accumulation of grass on the creek bottom and channel margin • Improving riparian and wetland function, improving fish and wildlife habitat quality, and helping to control erosion. Project Efficacy Project 11 was modeled using horizontal variations in the channel roughness with the riparian buffer along the channel margins. This was modeled as a 20-foot wide swath on either side of the channel, with a Manning "n" coefficient of 0.12 (for very dense riparian roughness) and the channel "n" remaining 0.045. This was applied for the riparian buffer extents to concentrate the flows at and below bankfull stage in the channel. Results of the modeling indicated that this project would lower water surface elevation within the reach for the 2-year event of 150 cfs. The water surface was lowered by approximately 0.1 foot in the floodplain adjacent the project site. This project would also help to increase channel velocities along the reach. Predicted in-channel velocities increased as a result of the project. For example, the in-channel velocity at one modeling point increased from 1.48 ft/s to 1.61 ftls, a nine percent relative increase. Increases in channel velocity may mitigate some of the sedimentation problems in the area. Based on recent modeling of potential hydraulic effects, Project 11 was predicted to reduce flooding and increase velocities potentially reducing sedimentation problems in this reach. The project would also enhance 77,500 square feet of riparian habitat area. Results of the modeling indicate that this project in File No. 1079/-005-00 December I 9, 2008 Page B-36 GEOfNGIN!fRS_.@ I I I I I I I I I I I I I I a u I I I I I I I I I I I I I I I I I I I I combination with Project l O would lower water surface elevation within the reach for the 2-year event of l 50 cfs. The water surface was lowered by approximately O. l foot between stations 5993 and 6821. This project would also help to increase channel velocities along the reach. In-channel velocities marginally increase as a result of the project. For example, at one hydraulic model transect location, the in-channel velocity increases from l.48 ft/s to l.6 l ft/s, a nine percent relative increase. These increases in channel velocity may mitigate some of the sedimentation problems in the area. Potential Challenges and Limitations This project would occur on lands owned by at least three private parties. The land is currently used for residential and livestock purposes. Some of the area used by livestock would need to be converted to enhanced wetland and riparian area, or at least fenced from use, for this project to succeed. It is unknown if these actions would be of interest to landowners. Landowners must grant permission for these projects to be implemented. At the time this report was written, there were uncertainties regarding landownership changes and contact information. Additional regulatory constraints may also be imposed on the proposed project due to the fact that much of May Creek in the May Valley was historically forested wetland (Conditions Report, King County l 995) or contains other critical areas. A wetland delineation and critical areas assessment would need to be completed to determine the extent and function of wetland and other habitat features at the site. Any impacts to stream buffers, wetlands and wetland buffers would need to be mitigated if the project were permitted and implemented. Planning-Level Cost Estimates Estimated Construction Costs: $89,200 (See Appendix C for details). Design, construction observation and permitting costs are not included as these costs can vary significantly. Permitting Management of lands for ongoing livestock and other agricultural purposes is currently permissible under local, state and federal laws. Verbal approval to proceed with the project was obtained from King County and the U.S. Army Corps of Engineers in May of 2007. Project plans were developed during July and August of 2007. Site access challenges resulted in postponement of project implementation. Ongoing site access challenges continues to preclude any further permitting work, detailed project design, or construction activities for this project at this site. File No. 1079/-005-00 December 19, 2008 Page 8-37 GEOENGINEERS.i PROJECT 12: INDIAN MEADOW CONFLUENCE AREA PROJECT Project 12 would include the removal ofreed canarygrass, and the construction of a pond, stream channel, and riparian habitat on the right bank of May Creek (Figure 8-12). Additional details are available for this project as a result of predesign work completed for Projects 11 and 13. Project 12 was not selected as a priority project for predesign work because it was not anticipated to have the level of benefit or support as the other two projects. This project was identified as a Category K project during the prioritization process. Site Location Project 12 is located at May Creek RM 4.85 in the west Y, of Section 2, T. 23 N ., R. 5 E., W.M in King County, WA. This proposed project is located at the confluence on May Creek and Indian Meadow Creek on property currently owned and managed by a private landowner. The site is located near the lower end of May Valley, the westernmost property line being approximately 1500 feet upstream from the 148 1 h Avenue SE bridge (Figure 14, Appendix A). Site Description The site is contained within a degraded wetland, located on the right (north) bank of May Creek. The land is currently used as horse pasture. Based on the Conditions Report, landuse activities in the May Valley eliminated a conifer and deciduous-based forested wetland, likely historically present at the site. The Condition Report also characterizes this area to be very low gradient (.::c 0.2 percent slope) and as being an "underfit" stream flowing through an agricultural and livestock-raising region. May Creek was channelized and re-aligned throughout the May Valley sometime between 1910 and 1936. Its previous form as a meandering, low-gradient stream was transformed into a straight channel. May Creek remains a relatively straight channel with little habitat complexity, in-channel wood, or variability in substrate composition (Figure 12, Appendix A). The wetland is predominantly pasture with some reed canarygrass and willow immediately adjacent the creek. This confluence area does not have a readily identifiable channel. Rather, reed canarygrass and sediment have accumulated at the site, eliminating the tributary channel and adding vegetation and sediment to the already impaired channel. This area no longer functions as a forested wetland, but does have some flood attenuation, nutrient assimilation, and habitat value as a degraded wetland. This area frequently floods. The project site is located immediately upstream from the low gradient section described in Project 11. This section of May Creek was previously the subject of restoration actions supported by King County. This area was planted with riparian vegetation and fenced to preclude pasture animals from approaching riparian plantings. During site visits, some May Valley landowners raised concerns that the riparian vegetation project resulted in berming of the creek banks, exacerbating flooding. Residents suggests that constructed berms were not allowing flood waters to return to the creek once flood levels have subsided. File No. 1079/-005-00 December /9, 2008 Page B-38 GeoENGINEER~ II I I I I I I I I I I I I I I D I I I I I I I I I I I I I I I I I I I I "' 1 a:: « (6' ~ l "' u "' 5 ~ 6· I Existing Conditions -scale 1 :1 ooo conceptual drawing ofponci.and riparian area \. ·i'! ~1-----------------..-------------------1 g ~ er GeoENGINEER~ Eart:1 Scieoea .. Ttctmalor; File No. /0791-005-00 December 19, 2008 Concepiuol.Drowing·Project,12 i-ruURt 1(1~ Page B-39 GEOENGINEERS.i Project Description Project 12 includes the installation of a pond and reed canarygrass abatement immediately adjacent to the confluence of May Creek and Indian Meadow Creek to create a sediment trap and off-channel habitat area. The existing May Creek channel would not be modified. This project would be designed to help reduce sediment deposition, remove vegetation constraining flow and help to maintain a free-flowing stream channel. These design elements should improve riparian and off-channel fish habitat and allow fish passage through the area upstream to other significant anadromous fish resource areas. The project would include construction of an off-channel pond at the confluence of May Creek and Indian Meadow Creek and reed canarygrass abatement at the pond site. The perimeter of the pond would be planted with native wetland trees and shrubs. The pond would be constructed roughly in a oval shape of approximately 1,600 square feet in area, aligned perpendicular to May Creek. Pond banks would have a 4 to I slope around its perimeter in order to minimize erosion risk and to support riparian and wetland trees and shrubs. Material excavated to form the pond would be disposed in upland area of the subject property. Project Efficacy This project is very conceptual in nature. Site specific survey work and hydraulic modeling would need to be completed to estimate the potential project benefits. Qualitatively speaking, reducing sediment loading from this unstable tributary would be expected to help reduce local flooding issues and improve downstream habitat. Further investigation into this project would be worthwhile. Quantitatively speaking, the project would create about 1,600 square feet of pool habitat, 70 linear feet of channel for fish and enhance 2,400 square feet of riparian habitat. Potential Challenges and Limitations The project is located within an active farm that currently experiences heavy use by horses and farm equipment traveling through the area. Some of the area used by livestock would need to be converted to riparian and off-channel habitat, or at least fence off, for this project to succeed. It is unknown if these actions would be of interest to landowners. Landowners must grant permission for these projects to be implemented. In addition, the sediment load from Indian Meadow Creek may be so excessive that the sediment trap/off-channel habitat pond would need to be maintained on a regular basis, or it would quickly fill and lose all function. Additional regulatory constraints may also be imposed on the proposed project due to the fact that much of May Creek in the May Valley was historically forested wetland (Conditions Report, King County 1995) or contains other critical areas. A wetland delineation and critical areas assessment would need to be completed to determine the extent and function of wetland and other habitat features at the site. Any impacts to stream buffers, wetlands and wetland buffers would need to be mitigated if the project were permitted and implemented. Planning-Level Cost Estimates Estimated Construction Costs: $33,900 (See Appendix C for details). Design, construction observation and permitting costs are not included as these costs can vary significantly. File No. /079/-005-00 December 19. 2008 Page B-40 GeoENGtNEEIIS...@ I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Permitting We anticipate needing local, state, and federal authorization to proceed with this project. For instance, development of an off-channel pond will require a King County Clearing and Grading Permit. A related aspect of this activity is the potential to affect wetlands. We recommend pursuing approval from the U.S. Army Corps of Engineers under Nationwide Permit Number 27 (U.S. Army Corps of Engineers (ACOE) Section 404). Actions proposed for this project will also need to go through State Environmental Policy Act (SEPA) approval. We recommend the use ofa SEPA Checklist, and with concurrence from King County that this project should proceed this year, anticipate timely approval. The project will result in actions in Indian Meadow Creek. Therefore we may need authorization under the US Endangered Species Act (ESA), and may to need to complete a JARPA and secure Hydraulic Project Approval (HPA). It may be possible to expedite permitting through authorization from the US Anny Corps may under Nationwide 27 and use of streamline permitting under the Washington State Department of Fish and Wildlife (WDFW Hydraulic Project Approval (HPA), SEPA Checklist, and Specific Project Information Forms (SPIF). It may also be necessary to consult with local Tribes (e.g. Muckelshoot Tribe) as the work would be in-channel and is proposed to have habitat enhancement value. The following permits and approvals may also be required: • Washington State Department of Ecology (Ecology) 401 Water Quality Certification • King County Critical Areas Review • Compliance with the King County Shoreline Regulations • Tribal and WDFW area biologist consultation File No. /079/-005-00 December 19, 2008 Page B-41 GEOENGINURS...a, PROJECT 13: COLASURDO OFF-CHANNEL POND/WETLAND ENHANCEMENT Project 13 includes in installation of a new pond, reed canarygrass abatement and native plant restoration (Figure B-13). Project 13 would compliment Project IFP 2, were both project implemented together. Project 13 was identified as a Category N project during the prioritization process. This project was selected as a pilot project for inclusion in the Pre-Design Report (GeoEngineers 2007) in an attempt to begin mitigating some of the negative effects of flooding, erosion, and the highly invasive weed, reed canarygrass. Project details are also presented in the Pre-Design Report. It is one of four projects selected for pilot project implementation in 2007 and 2008. As a result, the following is a more detailed overview of this project, as compared to the majority of the other projects in this CRP. The detail is provided based on the additional work that the project team completed during the predesign process. Site Location The proposed project is located at May Creek RM 5.2 in south 1/2 of Section 2, T. 23 N., R. 5 E., W.M. in King County, Washington. This project is located in the southeast portion ofa private property located at 10736 1541 " Place. The site is located approximately 1500 feet above the confluence of May Creek and Indian Meadow Creek from the 148'" Avenue SE bridge (Figure 14, Appendix A). Site Description The site is an active horse pasture on left bank of May Creek. Based on the Conditions Report, landuse in the area virtually eliminated wetlands likely historically present at the site. The Conditions Report also describes the creek as very low gradient(::: 0.2 percent slope) and is described in the Conditions Report (1995) as being an "underfit" stream flowing through an agricultural and livestock-raising region. May Creek was channelized and re-aligned throughout the May Valley sometime between 1910 and 1936. Its previous form as a meandering, low-gradient stream was transformed into a straight channel which serves as a property boundary between some valley landowners. To date it remains a relatively straight channel with little habitat complexity, in-channel wood, or variability in substrate composition (Figure 12, Appendix A). The remaining wetland is predominantly pasture with some reed canarygrass and willow immediately adjacent the creek. The riparian area was enhanced in the mid 1990s, and has created some additional flood attenuation, nutrient assimilation, and habitat value. The enhanced riparian area has helped improve channel function and sediment transport processes. The section of May Creek upstream from Project 11 but downstream from Project 13, where riparian enhancements were previously made, is relatively free flowing and has reasonable fish passage and aquatic habitat for such a low-gradient stream. This area does, however, occasionally flood. The project site is located on the southwest side of May Creek immediately upstream from the low gradient section described in Project 11. This section of May Creek is functioning somewhat better than other sections of the creek. It has moderate stream velocities that, at the time of the last site visit in 2007, were capable of moving fine sediment downstream, thus maintaining a small to medium gravel substrate and limited channel complexity. Unlike many areas of May Creek, the floodplain is slightly perched above the creek, making it possible to store water, if the proposed pond is constructed. This section of May Creek was previously the subject of restoration actions supported by King County. This area was planted with riparian vegetation and fenced to preclude pasture animals from approaching riparian plantings. The May Valley Environmental Council (MVEC) has previously raised concerns that the riparian vegetation project resulted in berming of the creek banks. MVEC suggests that constructed berms were not allowing flood waters to return to the creek once flood levels have subsided. File No. 10791-005-00 December 19, 2008 Page B-42 GEOfNGINEERt@ I I I I I I I I I I I I I I I I I D I I I I I I I I I I I I I I I I I I I .. - 0 Existing Conditions -scale 1 :1000 ....• ·. ' '( . g . ·I,\.~:;;\ ~~1,,,···.' •--;.,,'·; . ' .... ' .. ·~ ,v ~ ''-.o~ '" Conceptual drawing of pond and riparian area GeoENGINEERS Q F.utb St:brnttt • T1ttwtr,o File No. 10791-005-00 December 19, 2008 Conceptual Drawing Project 13 FIGURE B-13 Page B-43 GEOENGINEERS.0 Project Description Project 13 includes the installation of a pond to create an off-channel habitat area on the left bank of May Creek. The existing May Creek channel would not be modified. The wetland pond would be approximately 0.25 acres in area in the south-east portion of a private property adjacent May Creek. The perimeter of the pond would be planted with native wetland and riparian trees and shrubs. The pond would be constructed roughly in an oval shape of approximately 175 feet in length by 60 feet in width, aligned parallel with May Creek. Pond banks would have a 20: I side slope around its perimeter in order to minimize erosion risk and to support riparian and wetland trees and shrubs. Material excavated from the pond would be disposed in upland area of the subject property. Construction of the pond is expected to provide both direct and indirect flood reduction benefits. Direct flood reduction benefits include providing of an area for floodwaters to drain from the southeast portion of the property. This would also help reduce the levels of sediment deposition and help maintain a free- flowing stream channel. If the pond were connected to the main channel, the project would improve riparian and off-channel fish habitat. This project could be implemented with at least two alternative designs. Design one (I) could consider connecting the off-channel pond through a channel located at the downstream (northwest) end of the pond. Design two (2) would consider connecting the pond to May Creek through points both upstream (southeast) and downstream (northwest) ends of the pond. Project Efficacy The effects of Project 13 and 14 were modeled together. Project 14 is a storm water detention basin described in more detail later in this document. The wetland feature was modeled assuming a I-foot deep swale section with 20: I side slope. Flows in the wetland were assumed ineffective (i.e. disconnected from May Creek) until the overbank elevation was exceeded, then skimming flow over the wetland would take place. Modeling results showed that this project will have minimal effect on local water surface elevations-0.02 foot decrease for the 150 cfs event. Reach average velocities in the project vicinity were projected to decrease from 1.32 ft/s to 1.28 ft/s for the 150 cfs flow rate. The storm water runoff was modeled for the wetland enhancement Project 13 using the typical methodology proposed on other similar projects in the scope. The drainage area for this wetland enhancement project is 0. 77 acres. The storm water runoff will be reduced from 0.1 cfs to 0.043 cfs from the site, a 56 percent reduction. Based on modeling results, Project 13 was projected to provide minimal help reduce flooding effects, and have little effect on velocities in May Creek adjacent to the site. In addition to flood-related effects, the project will create about 3,500 square feet of wetland and enhance approximately 30,000 square feet of riparian and wetland buffer area. Potential Challenges and Limitations The project is located within an active farm. The project area is presently heavily used by horses. Some of the area used by livestock would need to be converted to the riparian and off-channel habitat area, or at least fenced, for this project to succeed. It is unknown if these actions would be of interest to landowners. Landowners must grant permission for these projects to be implemented. The landowner may desire the area to be used as a stock-water pond. While this would reduce direct effects on livestock on May Creek, it would likely reduce the utility of the pond as an off-channel habitat. File No. 1079/-005-00 December I 9, 2008 Page B-44 GeoENGINHR~ I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Additional regulatory constraints may also be imposed on the proposed project due to the fact that much of May Creek in the May Valley was historically forested wetland (Conditions Report, King County 1995) or contains other critical areas. A wetland delineation and critical areas assessment would need to be completed to determine the extent and function of wetland and other habitat features at the site. Any impacts to stream buffers, wetlands and wetland buffers would need to be mitigated if the project were permitted and implemented. Planning-Level Cost Estimates Estimated Construction Costs: $15,400 (See Appendix C for details). Design, construction observation and permitting costs are not included as these costs can vary significantly. Permitting We anticipate needing local, state, and federal authorization to proceed with this project. Development of an off-channel pond on the Colasurdo family property will require a King County grade and fill permit. Grade and fill actions would likely affect wetlands. We recommend pursuing approval from the U.S. Army Corps of Engineers under Nationwide Permit Number 27. This project will also need to go through State Environmental Policy Act (SEPA) approval. We recommend the use of a SEPA checklist. The project would not initially result in-water construction nor in the placement of fill in the creek. Work along the streambank and within the ordinary high water mark of the creek would a JARPA in order to obtain hydraulic project approval, SEPA approval, and ESA concurrence. It may also be possible to expedite permitting through streamlined HPA, SEPA Checklist, and Specific Project Information Forms (SPIF). In-channel work may necessitate consultation with ESA authorities and the local Tribes (e.g. Muckelshoot Tribe) as the work is proposed to have habitat enhancement value. Since a portion of the work may be completed below the ordinary high water mark (OHWM) and would result in fill to a critical area, the following permits and approvals may also be required: • U.S. Army Corps of Engineers (ACOE) Section 404 • Washington State Department of Ecology (Ecology) 401 Water Quality Certification • King County Clearing and Grading Permit • King County Critical Areas Review • Compliance with the King County Shoreline Regulations • Tribal and WDFW area biologist consultation File No. 10791-005-00 December /9, 2008 Page B-45 GEOENGINEERS.i PROJECT 14: COLASURDO STORMWATER DETENTION POND Project 14 proposes to help address flooding in the project vicinity by reducing stormwater flows to the May Valley (Figure B-14). Project 14 may complement the projected effects of Project 13 if also implemented. This project was identified as a Category J project during the prioritization process. Site Location Project 14 is located at May Creek RM 5.25 in the south half of Section 2, T. 23 N., R. 5 E., W.M. in the King County, Washington (Figure 3). The site is located approximately 1800 feet above the confluence of May Creek and Indian Meadow Creek in the southeast portion of the private property located at 10736 t54'h Place (Figure 14, Appendix A). Site Description The site is an active horse pasture on the left (south) bank of May Creek. Based on information in the Conditions Report (King County 1995), landuse in the area virtually eliminated the forested wetlands likely historically present at the site. The report also states that the Creek is very low gradient t, 0.2 percent slope) and is described in the Conditions Report ( 1995) as being an "underfit" stream flowing through an agricultural and livestock-raising region. May Creek was channelized and re-aligned throughout the May Valley sometime between 1910 and 1936. Its previous form as a meandering, low- gradient stream was transformed into a straight channel which serves as a property boundary between some valley landowners. To date it remains a relatively straight channel with little habitat complexity, in- channel wood, or variability in substrate composition (Figure 7, Appendix A). The wetland is currently predominantly pasture with some reed canarygrass and willow immediately adjacent the creek. This section of May Creek is relatively free flowing and has reasonable fish passage. This area occasionally floods. An unnamed stormwater drainage enters the property from the southwest. The stonnwater accumulates in a depression located in the southern corner of the property. Excessive rainfall and stormwater flows exceed the capacity of the depression and flood the pasture. The proposed stormwater detention pond project is located on the southwest side of May Creek upstream from the low gradient section described in Project l l and upslope from the wetland project described in Project 13. Just downstream from Projects 13 and 14 is a section of May Creek that is functioning somewhat better than other sections of the creek. It has moderate stream velocities that, at the time of the last site visit in 2007 were capable of moving fine sediment downstream, thus maintaining a small to medium gravel substrate and some channel complexity. The section of May Creek immediately adjacent Project 13 has low velocities and reed canarygrass encroaching on the channel, like may areas. Unlike many areas of May Creek, the floodplain in this area of the valley is slightly perched above the creek, making it possible to store water, if the proposed stormwater pond was constructed. File No. 10791-005-00 December 19, 2008 Page B-46 GEOENGINE!RS_g I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Existing Conditions -scale 1 :1000 ' ' ' ··.~~., . . , .. . i: ' \ • Conceptualdrawing of po~d an~ riparian area GeoENGINEER~ Drtll ~r;lem;e + TrclmtlkrlJ Conceptual Drawing Project.14 J:IGUR,E B 14 File No. 10791-005-00 Decemher 19, 2008 Page B-47 GeoENGINEERS~ Project Description This project would expand the storage capacity of the shallow depression in the southern-most comer of the property that is acting as a stormwater detention area. The existing stonnwater flow originates in the Renton Plateau Subarea to the south of May Valley and is then detained in this shallow depression. The existing pond would be excavated to encompass an area of approximately 0.5 acres to 0.86 acres. Pond banks would have a 4: I slope around the perimeter in order to minimize erosion risk and to support riparian and wetland trees and shrubs. Material excavated to form the pond would be disposed in the upland area of the subject property. Riparian and wetland trees and shrubs would be planted around the pond, with the exception of stockwater access points. The existing May Creek channel would not be modified. No work would be done on this project within 250 feet of May Creek. This project would help reduce flooding and sediment deposition in May Creek by reducing the frequency of flooding caused when the capacity of the detention area is exceeded. The section of May Creek adjacent and downstream from the detention pond site is presently impaired by sediment deposition, encroaching reed canarygrass, and frequent flooding. This project would not provide significant direct habitat benefits. The project would, however, reduce the sediment load and flooding events and reduce further degradation of channel conditions and reduction of fish passage. This project would also serve as a stockwater pond, reducing the direct effects on livestock on May Creek and the riparian area. Project Efficacy As previously mentioned, the hydraulic effectiveness of projects 13 and 14 were modeled together. There is already a storm water depression in the area which seasonally fills with water. The estimated length is I 00 feet and width 200 feet from GIS mapping analysis for an existing pond footprint of 0.45 acres. The increase in detention size could possibly bring it up to 0.86 acres. If the existing pond were three feet deep and it was excavated to six feet in depth, the total capacity change would be 230,000 cubic feet and the pond could retain 304,000 cubic feet of water. Analysis of regional gaging data provided by King County at the May Creek/Coal Creek Parkway crossing, reveals that a typical rainfall event producing a flood peak of 77 cfs, produces on the order of 22 million cubic feet of water runoff. This pond could retain approximately one percent of that runoff. So, locally, it could certainly retain any flood water inflows in the area. This pond was not quantified in the HEC-RAS analysis. Based on modeling results, Project 14 would have some localized flood mitigation benefits. The project will also restore about 24,000 square feet of riparian habitat. Potential Challenges and Limitations The project is located within an active farm. The project area is presently heavily used by horses. Some of the area used by livestock would need to be converted to the riparian and off-channel habitat area, or at least fenced, for this project to succeed. It is unknown if these actions would be of interest to landowners. Landowners must grant permission for these projects to be implemented. The landowner may desire the area to be used as a stock-water pond. This would reduce direct effects on livestock on May Creek, but may reduce the capacity of the pond if horse traffic increases sediment loading to the pond. Planning-Level Cost Estimates Estimated Construction Costs: $169,700 (See Appendix C for details). Design, construction observation and permitting costs are not included as these costs can vary significantly. File No. I 0791-005-00 December I 9, 2008 Page B-48 GEOENGINEER~ I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Permitting Local, state, and federal permit or regulatory authorization will likely be needed prior to proceeding with · this project. This project will require a grade and fill permitting. We recommend pursuing approval from the U.S. Anny Corps of Engineers under Nationwide Permit Number 27. Actions proposed for this project will also need to go through State Environmental Policy Act (SEPA) approval. We recommend the use of a SEPA Checklist. The project will not result in actions in the creek nor in the placement of fill in the creek or within 250 feet of the creek. Therefore we do not anticipate needing authorization under the US Endangered Species Act (ESA), JARP A, the Hydraulic Code or related aquatic resource protection regulations. File No. /079/-005-00 December 19, 2008 Page 8-49 GeoENGtNEERS.i PROJECT 15: MAY CREEK SIDE-CHANNEL PROJECT Project 15 proposes to help address flooding and fish passage by creating a side-channel to May Creek near the confluence of May Creek and Tributary 291-A (Figure B-15). Fish passage improvements made as part of this project would complement fish passage improvements proposed as part of Project 16 or Project IFP 3, were these other projects implemented. Project 15 was identified as a Category D project during the prioritization process. Site Location Project 15 is located between Creek RM 5.53 and RM 5.65 on May Creek, approximately 1,000 feet downstream from the I 64'h Avenue bridge crossing near River Mile (Figure 15, Appendix A). The downstream-most point of the project is located at the confluence of May Creek and tributary 291-A, continuing upstream for approximately 650 feet. The project would be constructed entirely on private properties located on the right bank of May Creek. Site Description The site is a degraded wetland on both banks of May Creek, and is presently being used for residential and horse pasture purposes. Based on the Conditions Report (King County 1995), landuse changes in the area degraded the coniferous and deciduous-based forested wetland likely historically present at the site. This portion of May Creek is described in the Conditions Report (King County 1995) and the Action Plan (King County 200 I) as an "underfit" stream flowing through an agricultural and livestock-raising region. It is also reported as being subject to flooding, erosion, stream fish habitat, sediment deposition due to the low gradient and prevalence of fine sediment, wetland habitat and related problems (Figure 8, Appendix A). The existing wetland is predominantly reed canarygrass and willow. This area no longer functions as a forested wetland, but does have some flood attenuation, nutrient assimilation, and habitat value as a degraded wetland. This area frequently floods, has degraded aquatic habitat, and poses a partial barrier to locally significant fish use areas in 291-A and the County-Cabbage Creek drainages located upstream. This section of May Creek does not have a readily identifiable channel because reed canarygrass and sediment have accumulated, virtually eliminating the channel. The GIS database developed by the project team supports these findings. The most prevalent features identified on this segment using the GIS database included channel constriction caused by the encroachment of vegetation and the accumulation of silt (Figure 8, Appendix A). Project Description Project 15 would construct a new side-channel on the right bank of the existing May Creek channel. Reed canarygrass abatement and planting of native wetland vegetation would help restore riparian area and help maintain effective flows and sediment transport processes. The existing May Creek channel and riparian area would not be modified. This project would help reduce flooding and sediment deposition in May Creek by improving flow and sediment conveyance. This project would improve fish habitat a number of ways. It would create upstream passage where current conditions are, at best, a partial barrier to fish passage. This project would also help create aquatic and riparian habitat where presently reed canarygrass and saturated soils produce an ill-defined channel. This may also improve water temperatures by increasing conveyance and providing full channel shading. Both sediment and vegetation would need to be removed from the project site to create the new side-channel. File No. 1079/-005-00 December /9, 2008 Page B-50 GeoENGINEEAS.i I • I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ' ' Existing Channel Conditions {, £1 I f .[ ( • \\ " Conceptual Drawing of Restored Channel•and Riparian Area GeoENGINEER~ .Conceptual Drawln,i Proj8ct 15. E.lr1lt S.ltot,o + Tt<wlOIY File No. !0791-005-00 December 19, 2008 Page B-51 FIGURE 0:15 GeoENGINEERSg Project Efficacy Modeling of Project 15 was completed assuming that a high flow bypass channel would be created that would be approximately 650 feet in length, have a IO-foot bottom-width, and side slope with a 3:1 ratio with two foot depth. For modeling purposes a Manning's "n" of0.045 was used for the main channel and bypass channel and a Manning's "n" of 0.06 was used in the channel overbank areas for the proposed project. Model results predicted that this project would lower water surface elevations by 0.4 feet in the side channel area at a design flow of 150 cfs flow. The water level drawdown effects were predicted to propagate upstream and should alleviate some local flooding problems. Local velocities will decrease from 2.45 ft/s to 1.84 ft/s for the 2-year event, which could result in added sedimentation problems in the reach if both channels were to remain in use by the creek. The purpose of this project is to allow existing sedimentation to claim what remains of the existing channel while the constructed channel would provides the primary fish passage and flow conveyance corridor. Potential Challenges and Limitations The project is located within a number of active farm parcels. Landowners must grant permission for these projects to be implemented. Some of the area used by livestock would need to be converted to the riparian and side-channel habitat area for this project to succeed. It is unknown if these actions would be of interest to landowners. Saturated soils and heavy vegetation may make channel construction and riparian restoration efforts challenging, time consuming, and more expensive as compared with other habitat restoration projects. Planning-Level Cost Estimates Additional regulatory constraints may also be imposed on the proposed project due to the fact that much of May Creek in the May Valley was historically forested wetland (Conditions Report, King County 1995) or contains other critical areas. A wetland delineation and critical areas assessment would need to be completed to determine the extent and function of wetland and other habitat features at the site. Any impacts to stream buffers, wetlands and wetland buffers would need to be mitigated if the project were permitted and implemented. Planning-Level Cost Estimates Estimated Construction Costs: $85,100 (See Appendix C for details). Design, construction observation and permitting costs are not included as these costs can vary significantly. Permitting A portion, and perhaps all, of the project will be completed below the ordinary high water mark (OHWM) and require placing fill in a critical area. As a result, the following permits and approvals will likely be required: • U.S. Army Corps of Engineers (ACOE) Section 404 o Washington State Department of Fish and Wildlife (WDFW) Hydraulic Project Approval • Washington State Department of Ecology (Ecology) 401 Water Quality Certification • King County Clearing and Grading Permit o SEPA Checklist, with King County lead o King County Critical Areas Review o Compliance with the King County Shoreline Regulations • Tribal and WDFW area biologist consultation File No. I 0791-005-00 December 19, 2008 PageB-51 GeoENGtNEERS.i I I I I I I I I I I I I D I I I I I I I I I I I I I I I I I I I PROJECT 16: 291-A CONFLUENCE AREA PROJECT Project 16 is primarily a tributary channel restoration and fish passage project. As part of the project recd canarygrass abatement and native plant restoration would occur, similar to several other projects being proposed as part of this CRP (Figure B-16). Dense stands of reed canarygrass monocultures have developed at the confluence of Tributary 291-A and May Creek, contributing to flooding, excessive channel siltation, impairment of fish passage, degradation of fish habitat, and loss of riparian and wetland function. This project was identified as a Category H project during the prioritization process. This project was selected as a pilot project to be completed in 2007 or 2008 in an attempt to begin mitigating flooding and some of the effects of the highly invasive recd canarygrass. Additional project details can be found in the Pre-Design Report (GeoEngineers 2007). As a result of this project being included in the Pre-Design Report, the following is a more detailed overview of this project as compared to the majority of the other projects in this CRP. The detail is provided based on the additional work that the project team completed during the pre-design analysis phase early in 2007. Site Location Project 16 is located at the confluence of May Creek with 291-A, including the lower 400 feet of Tributary 291-A (RM O to RM 0.1 ). The project would occur entirely on private properties located approximately 1,000 feet downstream from the I 64'h Avenue bridge crossing near RM 5.5 on May Creek (Figure 15, Appendix A). Site Description The site is a degraded wetland on the left (south) bank of May Creek. The Conditions Report (King County 1995) indicates that landuse changes in the area eliminated the conifer and deciduous-based forested wetland likely historically present at the site. This portion of May Creek is described in the Conditions Report and the Action Plan (King County 200 I) as an "underfit" stream flowing through an agricultural and livestock-raising region. It is also characterized as being subject to flooding, erosion, stream fish habitat, sediment deposition due to the low gradient and prevalence of fine sediment, wetland habitat and related problems. 291-A is identified in the Action Plan (2001) as a locally significant area because of the high habitat use by coho salmon and cutthroat trout. The existing wetland is predominantly reed canarygrass, willow, and shrubs. Reed canarygrass and sediment have accumulated at the site, virtually eliminating the channel in the lower portion of Tributary 291-A and in May Creek. This area no longer functions as a forested wetland, but it does have some flood attenuation, nutrient assimilation, and habitat value as a degraded wetland. This area frequently floods, has degraded aquatic habitat, and poses a partial barrier to locally significant fish use in 291-A and access to upstream LSRA in the County-Cabbage Creek drainage (Figure 8, Appendix A). The GIS database developed by the project team supports these findings. The most prevalent features identified in this area using GIS were channel constrictions caused by the encroachment of vegetation and the accumulation of silt (Figure 8, Appendix A). File No. /0791-005-00 December /9, 2008 Page B-53 GEOENGINEERS_tv 0- ~ "' ~ 1 0 ;,i 0 f 0: u i ij ~·· I Existing Channel Conditions 0 i Conceptual Drawing of Restored Channel and Riparian Area· -~i----------------------------1 6 s "' GeoENGINEER~ E.tn!I Sci~+ Tttbl.o!ao File No. J 0791-005-00 December 19, 2008 Concoptua1Drowing Project 16 H6UKt U,1ti Page B-54 GEOENGINE!R~ Iii ii I i I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I '· .-, ·., ,' ',. ,., .. '?1 · '• F , . . , ' .,.. There is no clearly defined confluence area between Tributary 291-A and May Creek due to obstruction by recd canarygrass. Project Description Project 16 would create a new channel for Tributary 291-A to directly connect the tributary to an open channel section of May Creek. The riparian area would be restored along the tributary by removing reed canarygrass and planting native wetland and riparian plant species to help maintain effective flows and sediment transport processes. The existing May Creek channel and riparian area would not be modified as part of this project, but would be converted to an open channel through Project 15. Creating the new channel would help reduce flooding and sediment deposition in May Creek by improving flow and sediment conveyance. This project would improve fish habitat a number of ways. The new channel would remove the partial or complete barrier to fish passage caused by the obscured nature of the current channel. This project would also directly improve aquatic and riparian habitat by removing reed canarygrass and saturated soils and by creating a defined channel. This project may also improve water temperatures by increasing conveyance and providing full channel shading. File No. 1079/-005-00 December 19, 2008 Page B-55 GEoENGINEEIIS _9 Anticipated benefits of Project 16 include: o Enhanced passage of fish (coho and cutthroat) up Tributary 291-A (a Locally Significant Resource Area, LSRA), o Enhanced fish habitat in confluence area (rearing habitat in low-velocity mixing zone), o Better containment of flood waters in channel and pond, o Silt reduction including in-channel and tributary confluence area, and o Floodwaters are anticipated to move out of291-A and off the floodplain at a higher rate. Project Efficacy This project is very conceptual in nature. Site specific survey work and hydraulic modeling would need to be completed to estimate the potential project benefits. There was insufficient data to model potential hydraulic or hydrologic benefits at this time. Qualitatively speaking, reducing sediment loading from this unstable tributary would be expected to help reduce local flooding issues and improve downstream habitat. In addition, development of a clear passage corridor and confluence area between Tributary 291-A and May Creek would better enable coho salmon (Oncorhynchus kisutch) and cutthroat trout (0. clarki) access to a Locally Significant Resource Area (LSRA) as identified in the Action Plan (King County 200 I). Further investigation into this project would be worthwhile. Quantitatively speaking, the project would create about 200 linear feet of channel for fish and enhance 8000 square feet of riparian habitat. Potential Challenges and Limitations The project is located on two parcels. Both landowners must provide permission to construct this project. Access to view the area was granted by one landowner, but permissions have been more difficult to obtain from the neighbor. Some of the area would need to be converted from current uses to the riparian and side-channel habitat area for this project to succeed. It is unknown if these actions would be of interest to landowners. Saturated soils and heavy vegetation may make channel construction and riparian restoration efforts challenging, time consuming, and more expensive as compared with other habitat restoration projects. Additional regulatory constraints may also be imposed on the proposed project due to the fact that much of May Creek in the May Valley was historically forested wetland (Conditions Report, King County 1995) or contains other critical areas. A wetland delineation and critical areas assessment would need to be completed to determine the extent and function of wetland and other habitat features at the site. Any impacts to stream buffers, wetlands and wetland buffers would need to be mitigated if the project were permitted and implemented. Planning-Leve/ Cost Estimates Estimated Construction Costs: $63,200 (See Appendix C for details). Design, construction observation and permitting costs are not included as these costs can vary significantly. File No. 1079/-005-00 December 19, 2008 Page B-56 GEOENGINEER~ I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Permitting Work will be completed below the OHWM and will result in placing fill in a critical area. As a result, the following permits and approvals, therefore, will likely be required: • U.S. Anny Corps of Engineers (ACOE) Section 404 • Washington State Department of Fish and Wildlife (WDFW) Hydraulic Project Approval • Washington State Department of Ecology (Ecology) 40 I Water Quality Certification • King County Clearing and Grading Permit • SEPA Checklist, with King County lead o King County Critical Areas Review o Compliance with the King County Shoreline Regulations • Tribal and WDFW area biologist consultation File No. /079/-005-00 December 19, 2008 Page B-57 GEOENGINEERSg PROJECT 17: MAY CREEK BEAVER MANAGEMENT DEMONSTRATION PROJECT Project 17 is primarily a flood control and fish passage project, achieved through manipulation of an existing beaver dam located a short distance downstream from the 164'" Avenue SE bridge crossing (Figure 8-17). This project was identified as a Category A project during the prioritization process. Site Location Project 17 is located on May Creek near RM 5.8. The site is located approximately 500 feet downstream of 164'" Avenue SE (Figure 15, Appendix A). Site Description The site has an open, flowing channel with several beaver dams. Riparian enhancement work was been completed on the north (right) bank of May Creek at the project site. The beaver dams in this section of May Creek generally control the water surface elevation. During a February 2007 site visit, it appeared that a beaver dam backed up water and flooded lands at the site to a point above the 164'" Avenue SE bridge. This backwater effect is likely contributing to sediment deposition upstream from the dams and may be aggravating flood-flow problems at the 164 1 " Avenue SE bridge. May Creek has excellent fish habitat downstream from one beaver dam with quality flows, velocities, and substrate types and heavy shading from mature riparian vegetation. Beaver dams, however, may be acting as a partial barrier to upstream fish migration. The water surface elevation of May Creek below the 164'" Avenue SE bridge is controlled by the beaver dam located downstream from the bridge. File No. /0791-005-00 December I 9, 2008 Page B-58 GEOENGINE!~ I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ,_ :,;; I 15 g .... !;l i I .; ' ' ""' ' C" >Q ,,)'"') . Existing Channel Conditions Conceptual drawing ·of beaver management project P.1------------------------------1 " n " Ill "' GeoENGINEER~ Earth ~r;lcm:c! .. Tldlmllap File No. /079/-005-00 Deamher 19, 2008 Conceptual Drawing p',oject 17 ~IGURE B 17 Page 8-59 GEOENGINURS_.@ Project Description This project would address flooding and fish passage problems at the site by notching the beaver dam or by installing a "Beaver Deceiver". The notched beaver dam would be expected to increase conveyance and reduce the water surface elevation of May Creek behind the dam. This project would augment work that appears to have already been completed at the site. During an October 15, 2007 site visit, OT AK noted that the beaver dam at the site of proposed Project 17 was previously notched. This project proposes to increase the width of an existing 4-foot wide by 2-foot deep notch in the beaver dam to a width of eight feet. 'i' O; ,,l" ' ',.'.' "'· I , •,,;. • ., 11<-; Indication of previous notching of the beaver dam downstream from the 164'" Street SE bridge crossing of May Creek. The "Beaver Deceiver", or similar non-invasive beaver management device would be installed to manage the elevation of water behind the beaver dam and the flow of water through the structure, without notching or removing the dam or beavers see: http://dnr.metrokc.gov/wlr/Dss/beavers/construction- seguence.htm. The beaver management project would be designed to maintain a water level that would minimize flooding effects upstream, maintain quality downstream habitat and allow fish passage to the other high value fish resource areas in the Country-Cabbage Creek drainage located upstream. File No. 10791-005-00 December 19, 2008 Page B-60 GEOENGINEE~ I . . I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Project Efficacy Although both the "Beaver Deceiver" and notching project arc viable options for mitigating flow through the beaver dam, only the beaver dam notching was modeled at this time. The beaver dam notching project was simulated by raising the channel bed 2 feet in the HEC-RAS model to simulate the effect of the existing beaver dam. Model results suggested that there would be significant backwater effects propagating upstream. Notching was simulated in the HEC-RAS model by utilizing the notching geometry recorded in the field. This geometry was a 4-foot notch width and a 2-foot notch depth at the beaver dam crest. HEC-RAS analysis indicates that this notching would lower local water surface elevations 0.6 feet for the 2-year event. The model predicted that water surface elevations at the l 64'h Avenue SE bridge crossing would be lowered 0.2 feet. The model suggested that notching would increase local velocities from 5.74 ft/s to 6.91 ft/s for the 150 cfs 2-year flood event. The HEC-RAS model produces locally high velocities in the vicinity of the beaver dam upstream and downstream of the dam. The HEC-RAS model predicts velocities in the 2 to 3 ft/s range for the 150 cfs flow. Further notching is suggested for this dam through the construction of an 8-foot notch reduced to the existing grade. Model results suggest than an 8-foot notch would reduce the backwater by 0.5 feet at the 164th bridge crossing, greatly helping local flooding problems. With an 8 foot wide notch, modeling suggests that local velocities at the beaver dam would decrease from 5.74 ft/s to 4.76 ft/s. However reach average velocities were predicted to increase from 1.93 ft/s to 3.03 ft/s. Overall water level drawdown effects would propagate nearly 3,000 feet upstream in this scenario. Potential Challenges and Limitations Beavers were nearly extinct in North American due to trapping through the 1800's. Any actions taken in or around beavers and beaver habitat will require coordination with area biologists. Historical beaver management practices primarily relied on trapping and removal. Some landowners still prefer this method, and non-lethal trapping is still a permitting activity in some areas of the state. Landowners must grant permission for these projects to be implemented. This project would need to be completed on lands owner by multiple parties. It may be a challenge to get all parties to agree on a preferred method of beaver management at this site. The "beaver deceiver" and notching will have to be monitored regularly, to insure that the beavers have not prevented flow through these structures. Additional regulatory constraints may also be imposed on the proposed project due to the fact that much of May Creek in the May Valley was historically forested wetland (Conditions Report, King County 1995) or contains other critical areas. A wetland delineation and critical areas assessment would need to be completed to determine the extent and function of wetland and other habitat features at the site. Any impacts to stream buffers, wetlands and wetland buffers would need to be mitigated if the project were permitted and implemented. Planning-Level Cost Estimates Estimated Construction Costs: $15,200 (See Appendix C for details). Design, construction observation and permitting costs are not included as these costs can vary significantly. Fife No. /079/-005-00 Decemher 19, 2008 Page B-61 GEOENGINEERS_@ Permitting The work will be completed below the OHWM and will require placing fill in a critical area. As a result, the following permits and approvals likely will be required: • U.S. Army Corps of Engineers (ACOE) Section 404 • Washington State Department of Fish and Wildlife (WDFW) Hydraulic Project Approval • Washington State Department of Ecology (Ecology) 401 Water Quality Certification • King County Clearing and Grading Permit o SEPA Checklist, with King County lead • King County Critical Areas Review • Compliance with the King County Shoreline Regulations o Tribal and WDFW area biologist consultation File No. 10791-005-00 December /9, 2008 Page 8-6:Z GEOENGINEfRtai' I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I PROJECT 18: 164TH AVENUE SE CONVEYANCE PROJECT Project 18 was developed in an effort to alleviate flooding problems at the l 64'h Avenue SE bridge crossing site, and to reduce backwater effects that may be worsening flooding in the project area. This project proposes to improve conveyance under the I 64'h Avenue SE road utilizing a high-flow channel and culvert on the right (north) bank of May Creek (Figure B-18). This project was identified as a Category B project during the prioritization process. Site Location Project 18 is located at May Creek RM 5.9. The site is located at the intersection of 164'h Avenue SE and May Creek in King County, Washington (Figure 16, Appendix A). Site Description The site includes degraded wetlands on both the upstream and downstream sides of the I 64'h Avenue SE bridge and is effected by beaver dams on the downstream side of the bridge (Project 17). Based on the Conditions Report, landuse changes in the area eliminated the coniferous and deciduous-based forested wetlands likely historically presenting the valley, including at the site. The remnant wetland is predominantly reed canarygrass and willow. This section of May Creek is an undersized channel with ongoing loss of channel capacity as the result of sediment deposition and encroachment of reed canarygrass and other riparian shrubs. This area no longer functions as a forested wetland, but does have some flood attenuation, nutrient assimilation, and habitat value as a degraded wetland. The area frequently floods (Figure 9, Appendix A). Project Description Project 18 would construct a new high-flow channel under l 64'h Avenue SE, to the right of May Creek, to accommodate high flows without altering the existing bridge or channel alignment. The existing May Creek channel would not be modified. This project would be designed to help convey flood water and sediment past 1641h Avenue SE. This would reduce flooding, sediment deposition, and loss of channel capacity upstream from 164 1h Avenue SE. The project would help to maintain a free-flowing stream channel in May Creek. Project Efficacy This project was modeled as a high flow bypass culvert on the l 64'h crossing, consisting a IO-foot wide by 4-foot tall culvert. Analysis of the efficacy of the bypass culvert was modeled concurrent with the beaver mitigation project, due to the close spatial proximity. The upstream culvert invert was placed at an elevation of316 feet and the downstream invert was placed at 315.5 feet. The model predicted that the overall effect of this project was a reduction in local velocities and a reduction in water surface elevation at the bridge crossing. The local velocity at the upstream side of the bridge crossing is reduced from 2.55 ft/s to 2.12 ft/s for the 2-year 150 cfs flow rate. When coupled with the beaver mitigation project, this bypass channel could be expected to lower the water surface elevation 0.47 feet at the upstream side of the bridge for the 150 cfs flow. Independent from the beaver management project, the bridge culvert project was predicted to offer little change in water surface elevations at the bridge crossing. However, the reduction in water surface elevation when coupled with beaver management could help alleviate flooding upstream of the bridge as well as addressing any current freeboard issues at the bridge crossing. The flood reduction benefits were modeled to extend approximately 2,300 feet upstream from the bridge. File No. !079/-005-00 Deeemher 19, 2008 Page B-63 GEOENGINEERS _.1} co 1l 1-- ~ ;,;; I !J. 'el a ~- l 8. Existing Conditions .. ~:Jite_·" ... - .,~-- ,-;~:~,., Conceptual Orawing,of high-flow channel and culvert ~1--------------------------------1 I o:. GeoENGINEER~ Eart!I Sc:illbCt+ tect.nal:an File No. I 079 I -005-00 December /9, 2008 Conceptual Drawing Project.18 HuUKt ll,.1H Page B-64 GEOfNGINEER~ I I I I I I I I • I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Potential Challenges and Limitations Work in this area would need to be well coordinated to minimize the effects on traffic using I64'h Avenue SE. This road is heavily used and long-term closure would not be well received by residents or others that frequently use this road. King County may already be considering bridge or road improvements in the area. Coordination with county roads staff would be required to avoid duplication of effort or competing projects. The project would also include action on lands presently used ofresidential and animal pasture purposes. Landowners would need to grant permission for these projects to be implemented. Additional regulatory constraints may also be imposed on the proposed project due to the fact that much of May Creek in the May Valley was historically forested wetland (Conditions Report, King County 1995) or contains other critical areas. A wetland delineation and critical areas assessment would need to be completed to determine the extent and function of wetland and other habitat features at the site. Any impacts to stream buffers, wetlands and wetland buffers would need to be mitigated if the project were permitted and implemented. Planning-Level Cost Estimates Estimated Construction Costs: $160,200 (See Appendix C for details). Design, construction observation and permitting costs are not included as these costs can vary significantly. Permitting A portion of the work will be completed below the OHWM and will require in placing fill in a critical area. As a result, the following permits and approvals likely will be required: • U.S. Army Corps of Engineers (ACOE) Section 404 • Washington State Department of Fish and Wildlife (WDFW) Hydraulic Project Approval • Washington State Department of Ecology (Ecology) 401 Water Quality Certification • King County Clearing and Grading Permit • SEPA Checklist, with King County lead • King County Critical Areas Review • Compliance with the King County Shoreline Regulations • Tribal and WDFW area biologist consultation File No. /079/-005-00 Decemher 19, 200R Page B-65 GEOENGINEERS_@ PROJECT 19: TRIBUTARY 291-8 CONFLUENCE AREA PROJECT Project 19 would require the removal of reed canarygrass, and the construction of a wetland pond and buffer area and stream channel on the left (south) bank of May Creek at the present location of Tributary 291-B (Figure B-19). The purpose of the project would be to improve management of storrnwater runoff from Tributary 291-B, located just upstream from the 164'h Avenue SE bridge crossing. Benefits of Project 19 may be significantly improved with the concurrent implementation of Projects 17, 18, and lFP 3. Project 19 was identified as a Category L project during the prioritization process. Site Location Project 19 is located at May Creek RM 5.9 to RM 5.96. The site is located immediately upstream from the 164 1h Avenue SE crossing at the confluence of Tributary 291-8 and May Creek (Figure 16, Appendix A). Site Description Based on information in the Conditions Report, landuse changes in the area eliminated the forested wetland likely historically present at the site. The site is currently a degraded wetland on both banks of May Creek and is predominantly vegetated with reed canarygrass and willow. The site is used as a livestock pasture. The lower portions of Tributary 291-8 do not have a readily identifiable channel (Figure 9, Appendix A). May Creek, however currently has an open, flowing channel immediately upstream from the I 64'h Avenue SE bridge. Reed canarygrass and sediment have accumulated at the site eliminating the lower portion of291-B and a short distance upstream on May Creek. Project Description Implementation of Project 19 would result in the construction of a new channel connecting Tributary 291-8 to the left bank of the open channel section of May Creek. Tributary 291-8 would be routed through a constructed wetland and enhanced buffer area to help attenuate storrnwater flows and sediment contributions from Tributary 291-8. The wetland would also be enhanced to help assimilate high flows and sediment loads in May Creek. The existing riparian area would be improved to help maintain effective flows to reduce flooding and improve sediment transport processes to reduce sediment deposition. The existing May Creek channel would not be modified as part of this project. The improved riparian and wetland areas would also provide better fish habitat. The new channel would improve fish passage upstream. This project would also improve water temperatures by increasing conveyance and providing full channel shading. Project Efficacy This project is very conceptual in nature. Site specific survey work and hydraulic modeling would need to be completed to estimate the potential project benefits associated with changes to Tributary 291-B. There was insufficient data to model potential hydraulic or hydrologic benefits at this time. Qualitatively speaking, reducing sediment loading from this unstable tributary would be expected to help reduce local flooding issues and improve downstream habitat. Further investigation into this project would be worthwhile. Quantitatively speaking, the project would enhance approximately 5,000 square feet ofriparian habitat, 4,300 square feet of emergent wetland, and almost 21,000 square feet of wetland buffer area. The potential benefits of wetland buffers proposed as part of Projects 19 and 20 were modeled simultaneously. Project 19, an estimated 0.58 acre wetland and buffer area, was modeled as approximately 120 feet wide and 280 feet long oriented in a longitudinal direction along May Creek. The wetland buffers were modeled using the same methodology as was used for other wetland buffer projects described earlier in the CRP, generally using the HEC-RAS model. Fife No. /079/-005-00 Decemher 19, 2008 Page B-66 GeoENGINEER~ I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Existing Channel Conditions ~ :.i ! "' V i .... O· tel I o, ' 'I .. . ,• ·-. ' \' '; . ' . . , t ... < ~-----------------------------------t ,, n ,, @ "' GEOENGINEER~ EJErtlt ~c;trm;e + Trcrm'OlulJ File No. /0791-005-00 December /9, 2008 Conuptual Drawing Proj@ct.19 FIGURE B 19 Page 8-67 GEOENGINEERS g Hydraflow modeling results indicated that the 2-year storm runoff for the Project 19 site would be reduced 52 percent from 0.084 cfs to 0.04 cfs. Flood attenuation calculations indicate that this wetland complex (combined Project 19 and 20) would have the potential to attenuate approximately 2 percent of the total stormwater volume of a typical event with a peak flow of78 cfs. Model results suggest that water surface elevations upstream of the 164 1h Street crossing would not be affected by this project for the 2-year event, assuming that Projects 18 and 17 were not implemented. Channel velocities were predicted to slightly decrease from 0.34 ft/s to 0.27 ft/s. The predicted channel velocities were very low in this reach, even without implementation of this project. New survey data did not extend more than 50 feet upstream of the bridge crossing. Therefore, old FEMA cross section data was utilized in this reach. Field observations made during a February 2007 site visit confirmed, however, that backwater effects of the beaver dam extended upstream from Project 19. Potential Challenges and Limitations The project is located adjacent to 1641h Avenue SE. Construction work would benefit from ease of site access, but may congest the highly used intersection at 1641h Avenue SE and SR-900. Some of pasture land would be converted from current uses to the constructed channel, riparian habitat and wetland area. It is unknown if these actions would be of interest to the landowner. Landowners must grant permission for these projects to be implemented. Saturated soils at the project location may make construction of the channel, wetland and riparian areas challenging, time consuming, and more expensive as compared with other habitat restoration projects. Additional regulatory constraints may also be imposed on the proposed project due to the fact that much of May Creek in the May Valley was historically forested wetland (Conditions Report, King County 1995) or contains other critical areas. A wetland delineation and critical areas assessment would need to be completed to determine the extent and function of wetland and other habitat features at the site. Any impacts to stream buffers, wetlands and wetland buffers would need to be mitigated if the project were pennitted and implemented. Planning-Level Cost Estimates Estimated Construction Costs: $61,600 (See Appendix C for details). Design, construction observation and permitting costs are not included as these costs can vary significantly. Permitting A portion of the work will be completed below the OHWM and will require fill placement in a critical area. As a result, the following permits and approvals likely will be required: o U.S. Army Corps of Engineers (ACOE) Section 404 o Washington State Department of Fish and Wildlife (WDFW) Hydraulic Project Approval o Washington State Department of Ecology (Ecology) 40 I Water Quality Certification o King County Clearing and Grading Permit o SEP A Checklist, with King County lead o King County Critical Areas Review o Compliance with the King County Shoreline Regulations o Tribal and WDFW area biologist consultation File No. 10791-005-00 December 19, 2008 Page B-68 GEOENGIN!ER~ I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I PROJECT 20: STORMWATER/SEDIMENT RETENTION AREA Project 20 would require the removal of reed canarygrass, and the construction of a wetland pond, stream channel and buffer on the left (south) bank of May Creek at the present location of an unnamed stormwater drain (Figure B-20). The purpose of the project would be to improve management of stormwater runoff at this site located just upstream from the 164'" Avenue SE bridge crossing. Benefits of Project 20 may be significantly improved with the concurrent implementation of Projects 17, 18, 19, and IFP 3. This project was identified as a Category L project during the prioritization process. Site Location Proposed Project 20 is located at a point adjacent May Creek near RM 6.0 (Figure 16, Appendix A). The site is located approximately 500 feet upstream from the 164'" Avenue SE crossing over May Creek in King County, Washington. Site Description The proposed site is a stormwater drainage area that crosses the property through degraded wetland. Based on the Conditions Report, landuse changes in the area eliminated the forested wetland likely historically present at the site. The area is presently used as a livestock pasture. The stormwater flow does not flow to May Creek through a readily discemable channel because reed canarygrass and sediment have accumulated at the site. May Creek is a relatively open, flowing channel adjacent the project area. The area frequently floods (Figure 9, Appendix A). Project Description This project would create a new tributary stream channel, wetland and wetland buffer at the site, connecting the existing stonnwater drainage swale to the open channel of May Creek. The stormwater drainage system would be routed through a constructed wetland and enhanced buffer area to attenuate stormwater flows, sediment and nutrient runoff. The wetland would also be situated and improved to help assimilate high flows and sediment loads in May Creek. The existing riparian area would be improved to help maintain effective flows to reduce flooding and improve sediment transport processes to reduce sediment deposition. The existing May Creek channel would not be modified. The improved riparian and wetland areas would also help improve fish habitat. This project may also help improve water temperatures in May Creek by increasing conveyance and providing full channel shading. Project Efficacy This project is very conceptual in nature. Site specific survey work and hydraulic modeling would need to be completed to estimate the potential project benefits associated with changes to the stormwater drain. There was insufficient data to model potential hydraulic or hydrologic benefits at this time. Qualitatively speaking, reducing sediment loading from this unstable tributary would be expected to help reduce local flooding issues and improve downstream habitat. Further investigation into this project would be worthwhile. Quantitatively speaking, the project would enhance approximately 15,000 square feet of riparian area, 33,000 square feet of wetland buffer, and create approximately 7,500 square feet of emergent wetland habitat. Potential benefits of wetland buffers were modeled for Projects 19 and 20 simultaneously. Project 20, an estimated 0.93 acre wetland and buffer area, was estimated as approximately 120 feet wide and 300 feet long also oriented in a longitudinal direction along May Creek. The wetland buffers were modeled using the same methodology as was used for other wetland buffer projects described earlier in the CRP, generally using the HEC-RAS model. File No. /079/-005-00 December /9, 2008 Page 8-69 GEOENGINEERS _@ ~ u -~ ·Ir. -~ d, I!! t ~ !5 . "' li . l,; !<I IIJ .a iii -~ m Conceptual Drawing ofWetland and Riparian Restoration Area ~1---------------------------~ '6 " lil "' GeoENGINEER~ £anJ, S0i..t1 + TltluJolqy File No. /079/-005-00 December 19, 2008 Conceptual Drawing Project 20 FIGURE B-20 Page B-70 GeoENGIN!ER~ I i I I I i I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraflow modeling results indicated that the 2-year storm runoff for Project 20 would be reduced 54 percent from 0.125 cfs to 0.057 cfs. Flood attenuation calculations indicate that this wetland complex (both Project 19 and Project 20) would have the potential to attenuate approximately 2 percent of the total stormwatcr volume of a typical event a peak flow of 78 cfs. Model results suggest that water surface elevations upstream of the 1641h Street crossing would not be affected by this project for the 2-year event, assuming that Projects 18 and 17 were not implemented. Channel velocities were predicted to slightly decrease from 0.34 ft/s to 0.27 ft/s. The predicted channel velocities were very low in this reach, even without implementation of these projects. New survey data did not extend more than 50 feet upstream of the bridge crossing. Therefore, old FEMA cross section data was utilized in this reach. Field observations made during the February 2007 site visit suggest, however, that backwater effects of the beaver dam may extended upstream to Project 20 at certain flows. Potential Challenges and Limitations The project is located along SR 900. Construction may benefit from ease of site access but may congest the highly used SR-900. Much of the land would be converted to the constructed channel, riparian habitat and wetland area. Landowners would need to grant permission for this project to proceed. It is unknown if these actions would be of interest to the landowners. Saturated soils and heavy vegetation may make channel construction and riparian restoration efforts challenging, time consuming, and more expensive as compared with other habitat restoration projects. Additional regulatory constraints may also be imposed on the proposed project due to the fact that much of May Creek in the May Valley was historically forested wetland (Conditions Report, King County 1995) or contains other critical areas. A wetland delineation and critical areas assessment would need to be completed to detennine the extent and function of wetland and other habitat features at the site. Any impacts to stream buffers, wetlands and wetland buffers would need to be mitigated if the project were pennittcd and implemented. Conceptual Designs and Planning-Level Cost Estimates Estimated Construction Costs: $119,400 (See Appendix C for details). Design, construction observation and permitting costs are not included as these costs can vary significantly. Permitting A portion of the work will be completed below the OHWM and will require placement of fill in a critical area. As a result, the following pennits and approvals likely will be required: • U.S. Army Corps of Engineers (ACOE) Section 404 o Washington State Department of Fish and Wildlife (WDFW) Hydraulic Project Approval o Washington State Department of Ecology (Ecology) 401 Water Quality Certification • King County Clearing and Grading Permit • SEPA Checklist, with King County lead o King County Critical Areas Review • Compliance with the King County Shoreline Regulations • Tribal and WDFW area biologist consultation This project also is expected to disturb over I acre of ground. As a result, additional permitting steps will be required, including ACOE Section 404 project-specific permitting and requirements under Ecology's National Pollutant Discharge Elimination System (NPDES) to secure a Construction Stormwater General Permit. File No. In79/-005-00 December 19, 2008 Page B-71 GEOENGINEE~ PROJECT 21: HENDRIX CREEK CONFLUENCE AREA PROJECT Project 21 would require the removal of reed canarygrass, and the construction of a wetland pond and buffer area and stream channel on the left (south) bank of May Creek at the present location of Hendrix Creek (Figure B-21 ). The purpose of the project would be to improve management of stormwater runoff from Hendrix Creek as well as floodwater and sediment in May Creek. Benefits of Project 21 may be enhanced with the concurrent implementation of Project 22 and IFP 3. Project 21 was identified as a Category K project during the prioritization process. Site Location Project 21 is located between RM 6.2 and RM 6.45 on the left (south) bank of May Creek, where there should be a confluence area with Hendrix Creek (Figure 16, Appendix A). Site Description Based on the Conditions Report (King County 1995), landuse changes in the area has degraded the coniferous and deciduous-based forested wetland likely historically present at the site. The site is located on the left (south) bank of May Creek in a residential area open space that gets limited use. The existing wetland is primarily reed canarygrass and willow. May Creek is an open, flowing channel in the project area. In the lower portions of Hendrix Creek there is no readily identifiable channel (Figure 10, Appendix A). May Creek, however currently has an open, flowing channel in the area upstream from the J 64'h Avenue SE bridge. Reed canarygrass and sediment have accumulated at the site eliminating the lower portion of Hendrix Creek. Project Description Project 21 would create a wetland complex, buffer area, creek channel and enhanced riparian corridor adjacent to May Creek. The wetland would be designed to help assimilate high flows and sediment loads from both Hendrix Creek and May Creek. The riparian area would be enhanced to help maintain effective flows and sediment transport processes in the mainstem May Creek. The existing May Creek channel would not be modified. The intent of the project would be to help reduce flooding and sediment deposition in May Creek by improving flow and sediment conveyance. The improved riparian and wetland areas should also provide better fish habitat. This project may also improve water temperatures by increasing conveyance and providing full channel shading. Project Efficacy Projects 21 and 22 were modeled concurrently to determine project efficacy, due to their close spatial proximity to one another. Project 21 was modeled as an 8.3 acre wetland and wetland buffer complex located on the left (south) bank of May Creek, approximately 1,650 ft upstream of the J 64'h Street bridge crossing. This wetland was modeled to buffer both inflowing Hendrix Creek flows and to attenuate downstream flood waves in the riparian zone of May Creek. Project 21 extends 1,000 feet in the longitudinal direction of May Creek and was modeled with an approximate width of 250 feet in the perpendicular direction. Project 22 was modeled as a 5.9 acre wetland and wetland buffer on the right (north) bank of May Creek, extending 1,600 feet longitudinally and 250 feet, parallel to May Creek. Both projects were modeled with standard procedures used for similar projects described in this CRP. File No. /0791-005-00 December /9, 2008 Page B-72 GEOENGINEERS_B [i} I I I I I I I I I I I I I I I I • I I • I I I I I I I I I I I I I I I I I .... '-' " -"' t:; File No. 1079/-0()5-00 /Jecemher 19, 2008 . ' . . " ·i·: <I', Existing Conditions " .. <--·i,·:. = , . • (~f«i. '1 .. ~ ,, '!, . ,· i ; ' . I I ,! ' 0 Conceptual Drawing ofTributary;Wetland arid Riparian Restoration Area . Page B-73 GEOENGINEERS _a;' Hydraflow results indicated that land use change associated with Project 21 would reduce stormwater runoff from the site from 0.84 cfs to 0.39 cfs for the 2-year event a 54 percent reduction. The combined wetland complex associated with Projects 21 and 22 represent the largest proposed stormwater attenuation site on the project list. Attenuation volume calculations indicate that these two wetland complexes have the potential to attenuate up to 9.4 percent of the flood runoff volume for a typical storm hydrograph for the stream producing a peak flow of 78 cfs. This would be a significant attenuation of peak flood, indeed. Results suggested that Projects 21 and 22 would lower local velocities, based on a 150 cfs design flow, from 2.62 ft/s to 0.5ft/s in the downstream portion of the project and the water surfaces would increase very slightly (0.1 ft). In the upstream portion of the project velocities would not be lowered as severely. The velocity reductions predicted in the upper portion of the reach of May Creek, adjacent Projects 21 and 22 would be lowered from approximately 3.0 ft/s to 2.4 ft/s for the 150 cfs flow. In the upper reach model results indicate that local flood levels should be lowered by 0.4 feet on average with maximum water surface lowering of 0.8 feet. The implementation of this project should alleviate some local flooding problems in this area, but the significantly reduced velocities may result in sedimentation of the channel. Potential Challenges and Limitations A significant area of land would be converted to the riparian habitat and wetland complex area. It is unknown if these actions would be of interest to the landowners. Landowners would need to grant permission for these projects to proceed. Saturated soils may make stream channel, wetland, wetland buffer, and riparian area construction efforts challenging, time-consuming, and expensive as compared with other habitat restoration projects in this CRP. This project would disturb well over I acre of area, necessitating additional permitting and regulatory considerations. Additional regulatory constraints may also be imposed on the proposed project due to the fact that much of May Creek in the May Valley was historically forested wetland (Conditions Report, King County 1995) or contains other critical areas. A wetland delineation and critical areas assessment would need to be completed to determine the extent and function of wetland and other habitat features at the site. Any impacts to stream buffers, wetlands and wetland buffers would need to be mitigated if the project were permitted and implemented. Planning-Level Cost Estimates Estimated Construction Costs: $362,000 (See Appendix C for details). Design, construction observation and permitting costs are not included as these costs can vary significantly. File No. /0791-005-00 December 19, 2008 Page B-74 GEOENGINEER~ I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Permitting A portion of the work will be completed below the OHWM and will require placement of fill into to a critical area. As a result, the following permits and approvals likely will be required: o U.S. Army Corps of Engineers (ACOE) Section 404 o Washington State Department of Fish and Wildlife (WDFW) Hydraulic Project Approval o Washington State Department of Ecology (Ecology) 401 Water Quality Certification o King County Clearing and Grading Permit o SEPA Checklist, with King County lead o King County Critical Areas Review o Compliance with the King County Shoreline Regulations o Tribal and WDFW area biologist consultation The project would also disturb over 1 acre of ground. As a result, additional permitting will be required, including ACOE Section 404 project-specific permitting and requirements under Ecology's National Pollutant Discharge Elimination System (NPDES) to secure a Construction Stormwater General Permit. File No. /0791-005-00 December 19, 2008 Page B-75 GeoENGINEERSg PROJECT 22: NORTH HENDRIX WETLAND COMPLEX Project 22 would require the removal of reed canarygrass, and the construction of a wetland pond and buffer area on the right (north) bank of May Creek (Figure B-22). The purpose of the project would be to attenuate floodwater and sediment in May Creek. Benefits of Project 22 may be enhanced with the concurrent implementation of Project 21 and JFP 3. Project 22 was identified as a Category K project during the prioritization process. Site Location Project 22 is located adjacent May Creek between RM 6.18 and RM 6.42. The site is located on the right bank (north) of May Creek across from Hendrix Creek (Figure 16, Appendix A). Site Description Based on the Conditions Report (King County 1995), Janduse changes in the project area degraded the coniferous and deciduous-based forested wetland likely historically present at the site. The site presently functions as a degraded wetland on the north (right) bank of May Creek, in a residential area open space that gets limited use. The existing wetland is primarily reed canarygrass and willow. May Creek is an open, flowing channel in the project area, although the project site frequently floods (Figure 9, Appendix A). Project Description Project 22 would create a wetland complex, buffer area, and enhanced riparian corridor adjacent May Creek. The purpose of the wetland would be to help assimilate high flows and sediment loads in May Creek. The riparian area would be enhanced to help maintain effective flows and sediment transport processes. The existing May Creek channel would not be modified. In addition to addressing flooding and sedimentation problems, Project 22 would strive to improve riparian and wetland habitat areas, thereby potentially improving fish habitat. This project may also improve water temperatures by increasing conveyance and providing full channel shading. Project Efficacy Projects 21 and 22 modeled concurrently to evaluate efficacy, due to their close spatial proximity to one another. Project 22 was modeled as a 5.9 acre wetland and wetland buffer on the right (north) bank of May Creek, extending 1,600 feet longitudinally and 250 feet in the perpendicular direction., approximately 1,650 feet upstream of the 164'h Street bridge crossing. This wetland was modeled to buffer both inflowing Hendrix Creek stream flows and to attenuate downstream flood waves in the riparian zone of May Creek. Both projects were modeled with standard procedures used for similar projects described in this CRP. Hydraflow results indicate that land use change associated with Project 22 would result in a decrease in storrnwater runoff from 0.64 cfs to 0.29 cfs, a 54 percent decrease. The combined wetland complex associated with Proejcts 21 and 22 represent the largest proposed stormwater attenuation site on the project list. Attenuation volume calculations indicate that these two wetland complexes have the potential to attenuate up to 9.4 percent of the flood runoff volume for a typical stonn hydrograph for the stream producing a peak flow of78 cfs. This would be a significant attenuation of peak flood, indeed. Results indicate that Projects 21 and 22 would lower local velocities, based on a 150 cfs design flow, from 2.62 ft/s to 0.5ft/s in the downstream portion of the project and the water surfaces would increase very slightly (0.1 ft). In the upstream portion of the project velocities would not be lowered as severely. File No. /079/-005-00 December I 9, 2008 Page B-76 GEOENGINHRS_ai' I I I I I I I I I I I I I I I I I D I I I I I I I I I I I I I I I I I I I ... _, ·2 ~; ~ n .!( e, Q. ~ w ~ ~ tr V " li ~ ii D I I Existing Conditions ' . .. Conceptual Drawing of Wetland and Riparian Restoration Area ,. 'i .... ·' 0 l '· ~ ~~----------------------------------t " n ; "' GeoENGINEER~ Eirtrl .$tttllce + Ttamtltqy File No. /079/-005-00 Decemhe1· /9, 2008 conceptual Drawing Pfoject 22 J:IGURE 8'22 Page B-77 GEOENGINEER~ The velocity reductions predicted in the upper portion of the reach of May Creek, adjacent to Projects 21 and 22 would be lowered from approximately 3.0 ft/s to 2.4 ft/s for the 150 cfs flow. In the upper reach model results indicate that local flood levels should be lowered by 0.4 feet on average with maximum water surface lowering of 0.8 feet. The implementation of this project should alleviate some local flooding problems in this area, but the significantly reduced velocities may result in sedimentation of the channel. Potential Challenges and Limitations A significant area of land would be converted to the riparian habitat and wetland complex area. It is unknown if these actions would be of interest to the landowners. Landowners would need to grant permission for these projects to proceed. Saturated soils may make stream channel, wetland, wetland buffer, and riparian area construction efforts challenging, time-consuming, and expensive as compared with other habitat restoration projects in this CRP. This project would disturb well over I acre of area, necessitating additional permitting and regulatory considerations. Additional regulatory constraints may also be imposed on the proposed project due to the fact that much of May Creek in the May Valley was historically forested wetland (Conditions Report, King County 1995) or contains other critical areas. A wetland delineation and critical areas assessment would need to be completed to determine the extent and function of wetland and other habitat features at the site. Any impacts to stream buffers, wetlands and wetland buffers would need to be mitigated if the project were pennitted and implemented. Planning-Level Cost Estimates Estimated Construction Costs; $172,800 (See Appendix C for details). Design, construction observation and permitting costs are not included as these costs can vary significantly. Permitting A portion of the work will be completed below the OHWM and will require placement of fill into a critical area. As a result, the following permits and approvals likely will be required; o U.S. Army Corps of Engineers (ACOE) Section 404 o Washington State Department of Fish and Wildlife (WDFW) Hydraulic Project Approval o Washington State Department of Ecology (Ecology) 40 I Water Quality Certification o King County Clearing and Grading Permit o SEPA Checklist, with King County lead o King County Critical Areas Review o Compliance with the King County Shoreline Regulations o Tribal and WDFW area biologist consultation This project would likely disturb over I acre of ground. As a result additional permits will be required, including ACOE Section 404 project-specific permitting and requirements under Ecology's National Pollutant Discharge Elimination System (NPDES) to secure a Construction Stormwater General Permit. File No. 10791-005-00 December 19, 2008 Page B-78 GEOENGIN!ERS .i I I I I I I I NI II I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I PROJECT 23: COHO OFF-CHANNEL REARING HABITAT (OSBORN PROPERTY) Project 23 would convert an existing swale adjacent to May Creek into an off-channel habitat area (Figure B-23). This project was designed primarily as a habitat improvement project, given its close, downstream proximity to Country and Cabbage Creeks. This project may become important if coho salmon populations increase as a result of habitat improvements thorough implementation of Project 24 and IFP 3. This project was identified as a Category M project during the prioritization process. Site Location Project 23 is located adjacent May Creek near RM 6.45. The site is located approximately 300 feet downstream from the confluence of May Creek and Country Creek (Figure 17, Appendix A). Site Description The site is adjacent to one of the few free flowing, hard bottomed sections of May Creek. The site is currently maintained by residents with lawn and garden close to the bank of May Creek. Reed canarygrass and sediment have accumulated just downstream of the site. Reed canarygrass is prevalent at the site, but has not constricted the channel or impaired flows. As is true elsewhere in the valley, this section of May Creek was channelized and has a linear east-west orientation. In spite of having been channelized, this section of May Creek has clear, cool running water. The substrate is firm with a mix of sand and small gravel. Some medium and large gravel is present, as is large woody debris, cut banks, and rootwads. Overall the instream habitat appears healthy (Figure I 0, Appendix A). Project Description This project would create a small off-channel habitat area immediately adjacent to and just downstream from the confluence of May Creek and Country Creek. The existing May Creek channel would not be modified as it is functioning reasonably well. The proposed project would create an off-channel rearing area and improve habitat for coho salmon and other salmonids known to use the Country-Cabbage Creek drainage. The project is not expected to have significant flood attenuation, sediment reduction or erosion control benefits. Riparian vegetation planted at the site is expected to protect passage through this reach by helping to maintain the free flowing section of May Creek. The riparian vegetation will also help moderate water temperatures by shading May Creek. Project Efficacy This project is very conceptual in nature. Site specific survey work and hydraulic modeling would need to be completed to estimate the potential project benefits. There was insufficient data to model potential hydraulic or hydrologic benefits for this project at this time. Qualitatively speaking, there are few pool habitat areas in the May Valley segment of May Creek. Coho salmon (0. kisutch) prefer to rear in deep, coldwater habitat early in life. While it is unlikely that this project would provide significant hydraulic or hydrologic benefits, such a project could be coupled with other proposed projects, such as Project 24 to achieve a combined habitat improvement/flood reduction objective. Further investigation into this project seems warranted. Quantitatively speaking, the project would create about 200 linear fee of new side- channel habitat and 1,000 square feet of pool habitat, and approximately 1,500 square feet of enhanced riparian habitat. File No. 1079/-005-00 December 19, 2008 Page B-79 GEOENGINEERS .i i:: ! ~ ~ ~ " ,., B i I 8 ' ' \ ,:,i'.,· I . : • ..._ I \. J .· A ' .,,_ ' . ; . Existing-Conditions· '·('1"1,. J '"JI, Conceptual Drawing of off-channel coho rearing habitat area ~~-------------------------------1 6 ~ 0::. GeoENGINEER~ lllnHcleoce + Ttcwtm File No. 10791-005-00 December 19, 2008 Conceptual Drawing Project 23 FIGURE 8,23 Page B-80 GeoENGIN!!R~ (i I I i I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Potential Challenges and Limitations The landowner would need to grant permission for this project to proceed. The project area presently shows the effects of lawn and garden maintenance. Some of the area would be converted to riparian and off-channel habitat. It is unknown if these actions would be of interest to landowners. In addition, the current landowner may be in the process of selling the property. It is not known if and when a change in ownership might occur. This uncertainty makes it difficult to establish a timeline for implementation of such a project. Additional regulatory constraints may also be imposed on the proposed project due to the fact that much of May Creek in the May Valley was historically forested wetland (Conditions Report, King County l 995) or contains other critical areas. A wetland delineation and critical areas assessment would need to be completed to determine the extent and function of wetland and other habitat features at the site. Any impacts to stream buffers, wetlands and wetland buffers would need to be mitigated if the project were permitted and implemented. Project-Level Cost Estimates Estimated Construction Costs: $27,300 (See Appendix C for details). Design, construction observation and permitting costs are not included as these costs can vary significantly. Permitting A portion of the work will be completed below the OHWM and will require placing fill into a critical area. As a result, the following permits and approvals likely will be required: o U.S. Army Corps of Engineers (ACOE) Section 404 o Washington State Department of Fish and Wildlife (WDFW) Hydraulic Project Approval o Washington State Department of Ecology (Ecology) 401 Water Quality Certification o King County Clearing and Grading Permit o SEPA Checklist, with King County lead • King County Critical Areas Review o Compliance with the King County Shoreline Regulations o Tribal and WDFW area biologist consultation File No. 10791-005-00 December /9, 2008 Page B-81 GEOENGINU~ PROJECT 24: LOWER COUNTRY CREEK ENHANCEMENT PROJECT Project 24 is and aquatic habitat restoration project associated with three culvert replacement projects proposed in the Country-Cabbage Creek drainage (Figure B-24). These projects are proposed for two reasons. First, historic changes to the alignment of Country and Cabbage Creeks have created unstable channels that area subject to flooding, erosion and other problems. Second, the Action Plan (King County 200 I) has identified the Country-Cabbage Creek drainage as a Locally Significant Resource Area (LSRA) based on a high level of habitat utilization by coho Salmon (0. kisutch) and cutthroat trout (0. clarki). This project was identified as a Category l project during the prioritization process. Site Location Project 24 is within Country Creek, just upstream from its confluence with May Creek near RM 6.5 (Figure 17, Appendix A). The site is located within the lower 700 feet of Country Creek (RM Oto 0.15). Site Description The Country-Cabbage Creek drainage is one of the few free flowing, hard substrate tributaries to May Creek in the May Valley. The Country-Cabbage drainage has been identified by WDFW as a Locally Significant Resource Area due to high habitat use by coho Salmon (0. kisutch) and cutthroat trout (0. clarki). The site is presently used for lawn and garden by the residents and landscaping is maintained close to the bank of the creek, resulting is an overly narrow riparian corridor. As is true elsewhere in the valley, lower Country Creek was channelized. In spite of having been channelized, this section of creek has clear, cool running water. The substrate is firm with a mix of sand and small gravel. Some medium and large gravel is present, as is some woody debris. Overall the aquatic habitat appears relatively healthy, although simplified by channelization and clearing of riparian vegetation (Figure 10, Appendix A). Project Description Project 24 would restore a meandering creek orientation with a higher degree of habitat complexity and a corresponding riparian corridor to improve fish habitat. The project would use of combination of rock and wood bioengineered solutions to improve the coho salmon and cutthroat trout spawning and rearing habitat already present at the site. The project is also expected to have flood and erosion reduction benefits. With a linear orientation, high velocities are generated during high flows in the lower Country Creek periodically causing the creek to overflow its banks. Riparian vegetation planted at the site is expected to add further protection against erosion, flooding, and departures form the channel. Riparian vegetation would also help to moderate water temperatures by shading lower Country Creek. The existing May Creek channel in the confluence area would not be modified as it is functioning reasonably well. Project Efficacy This project is very conceptual in nature. Site specific survey work and hydraulic modeling would need to be completed to estimate the potential project benefits. There was insufficient data to model potential hydraulic or hydrologic benefits at this time. Qualitatively speaking, reducing sediment loading from this tributary would be expected to help reduce local flooding issues and improve downstream habitat. In addition, improving the passage corridor Country Creek and May Creek and increasing habitat complexity in lower Country Creek would better enable coho salmon (0. kisutch) and cutthroat trout (0. clarki) to make better use of this high fish use area (Figure 5, Appendix A). Further investigation into this project would be worthwhile. Quantitatively speaking, the project would create about 750 linear feet of instream habitat improvements and enhance approximately 8,000 square feet of riparian habitat. File No. /079/-005-00 December /9, 2008 Page B-82 GEOENGtNEERS,0 I I I I I I ll I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Existing Conditions Conceptual D'rawlng of.c,ffschannel coho rearing habitabuea GEOENGINEER~ bnh .$t:h!m:::ti ... Ttclamlqy FIGURE 82~ File No. /079/-005-00 Decemher 19. 2008 Page 8-83 GEOENGINEERS g Potential Challenges and Limitations Landowners would need to grant permission for this project to proceed. The project area presently shows the effects of lawn and garden maintenance. Some of the area would be converted to riparian and off- channel habitat. It is unknown if these actions would be of interest to landowners. It will be necessary to work with area biologists including representatives of local Tribes and WDFW to avoid impacts to existing, well-functioning habitat in the project area. Additional regulatory constraints may also be imposed on the proposed project due to the fact that much of May Creek in the May Valley was historically forested wetland (Conditions Report, King County 1995) or contains other critical areas. A wetland delineation and critical areas assessment would need to be completed to determine the extent and function of wetland and other habitat features at the site. Any impacts to stream buffers, wetlands and wetland buffers would need to be mitigated if the project were pennitted and implemented. Planning-Level Cost Estimates Estimated Construction Costs: $74,600 (See Appendix C for details). Design, construction observation and permitting costs are not included as these costs can vary significantly. Permitting A portion of the work will be completed below the OHWM, and will require placement of fill into a critical area. As a result, the following permits and approvals likely will be required: • U.S. Anny Corps of Engineers (ACOE) Section 404 • Washington State Department of Fish and Wildlife (WDFW) Hydraulic Project Approval o Washington State Department of Ecology (Ecology) 401 Water Quality Certification • King County Clearing and Grading Permit • SEPA Checklist, with King County lead • King County Critical Areas Review • Compliance with the King County Shoreline Regulations • Tribal and WDFW area biologist consultation File No. /0791-005-00 December /9, 2008 Page B-84 GEOENGINE!R~ ll i I I I I I I I I I I I I I I I ll I I I I I I I I I I I I I I I I I I I I PROJECT 25: CABBAGE CREEK CULVERT REPLACEMENT Project 25 is primarily a culvert replacement project, similar to several other projects being proposed in this CRP. This project was identified as a Category H project during the prioritization process. This project was selected as a pilot project to be implemented in 2007 or 2008 in an attempt to begin mitigating flooding and address some of the negative effects of erosion and downstream transport of sediment eroded from Cabbage Creek. This project was presented in a Pre-Design Report (GeoEngineers 2007). It is one of four projects identified as potential early-implementation projects proposed for implementation in 2007 and 2008. As a result, a more detailed overview is provided for this project, as compared to the majority of the other projects in this Appendix. The detail is provided for this project, based on the additional work that the project team completed during the predesign process in early 2007. Site Location Project 25 is located at the intersection of the SE May Valley Road and Cabbage Creek (Tributary 293). The culvert is located in the NWY., NEY. of Section 12, Township 23 N. Range 5 E., W.M., King County, Washington (Figure 17, Appendix A). Cabbage Creek joins Country Creek prior to flowing into May Creek at approximately RM 6.5 (Conditions Report, King County 1995). The culvert to be replaced under SE May Valley Road is located at approximately RM 0.2 along the Country/Cabbage Creek drainage. Site Description Country and Cabbage Creeks drain a portion of the uplands to the north of May Valley known as the Highlands (Conditions Report, King County 1995). Historic maps do not show Cabbage Creek as a tributary to either Country or May Creek. The Conditions Report, however, identifies Cabbage Creek as having been diverted into Country Creek. The current alignment of Country and Cabbage Creeks shows the direction of flow as south-southeasterly perpendicular to SE May Valley Road. After passing under SE May Valley Road, both creeks orient in an east-west direction, roughly parallel to SE May Valley Road before crossing the north side of May Valley to a point of confluence with May Creek. The Condition Report (King County 1995) describes the Country/Cabbage Creek drainage as having a fairly low gradient ( one to seven percent) through the shared, compound alluvial fan from its confluence with May Creek upstream to approximately RM 0.2. Between RM 0.2 and the road crossing, Cabbage Creek is contained in an artificial channel parallel to SE May Valley Road. Upstream from the culvert, the creeks flow through steep bedrock slope with a steep gradient (greater than 15 percent). Cabbage and Country Creeks both upstream and downstream from the SE May Valley Road have been altered. These alterations have resulted in flooding, erosion, habitat degradation and fish passage problems (Figure 10, Appendix A). The Country and Cabbage Creek stream channel, along the compound alluvial fan downstream from the road crossing, has alternating low (I) to high (12) width/depth ratio indicating incision or dredging into the compound alluvial fan. In spite of these alterations, the County/Cabbage Creek drainage is characterized as fairly stable, with relatively little watershed disturbance or risk of worsening conditions in the future (Conditions Report, King County 1995). File No. /0791-005-00 Decemher 19, 2008 Page B-85 GEOENGINEEIIS.i File No. I 0791 ·005·00 December I 9, 2008 The existing 60 inch round diameter corrugated metal culvert (intake) at Cabbage Creek in the May Valley, Washington. Page B-86 GEOENGINEERS.i I i I I I I I I I I I I I I I I I I I I ll I I I I I I I I I I I I I I I Project Description This project proposes to replace the dysfunctional culvert on Cabbage Creek to provide some immediate relief to flood, fish passage, and fish habitat problems identified in the Action Plan (King County 2001 ). The replacement will be designed in accordance with the stream simulation methodology specified in the WDFW manual titled "Design of Road Culverts for Fish Passage" (Bates 2003). The new structure will be designed to facilitate fish passage and access to an additional 0.22 miles of habitat available above the culvert, up to a natural barrier. The project is also expected to reduce erosion, bank failure and flooding by aligning the channel to orient the stream in the direction of the downstream channel rather than perpendicular. The proposed Cabbage Creek Culvert Replacement project includes the installation of a bottomless, concrete arch or similar structure to replace the existing culvert. The replacement culvert will be designed in accordance with the stream simulation methodology specified in the WDFW manual titled "Design of Road Culverts for Fish Passage" (Bates 2003). Stream simulation is a design process for creating natural stream processes within a culvert, with sediment transport, fish passage, flood and debris conveyance within the culvert intended to function as they would in a natural channel. The proposed structure will be located within the footprint of the existing SE May Valley Road prism. The roadway embankments in the vicinity of the wingwalls will require riprap to protect the embankments and wingwalls from scour. --""-F-~-...-- ' --, ''"""' """'"' ""'"""""' -CROSS SECTION Conceptual drawing of a pre-cast concrete arch bridge that could be used in place of the existing undersized culvert at Cabbage Creek in the May Valley, Washington. File No. 1079/-005-00 Decemher I 9, 2008 Page B-87 GeoENGINEERSg The alignment of the proposed culvert may be skewed relative to the existing road prism. Skewing the culvert would shift the outlet towards the orientation (west-flowing) of Cabbage Creek below the culvert, to help reduce flooding and erosion caused by the current orientation of the stream downstream from the existing culvert. This alignment will also reduce the potential for downstream scour. If left uncorrected, higher stream flows through the existing culvert and residual scour of the south bank of the creek downstream from the culvert may necessitate aggressive streambank treatments such as berms and bank armoring to reduce bank erosion. While such action may temporarily address scour and low recurrence flooding problems, such actions would only perpetuate erosion, flooding, fish passage, and fish habitat problems. A new streambed could be constructed inside the proposed culvert. A new channel could be lined with a gravel filter and substrate consisting of rounded gravel, cobbles, and boulders. In addition to protecting the structure and channel from scour and significant degradation, the larger elements of this substrate would create eddies to facilitate the upstream passage of fish. Footings for the proposed culvert would be set far enough below the proposed elevation of the stream channel to provide the necessary bearing capacity for the structure and adequate coverage for unanticipated scour and degradation. Footings would be protected from potential local scour with a layer ofriprap. If this project is implemented, construction crews should use a variety of Best Management Practices (BMPs) to control erosion and sediment transport throughout construction and continuing until the new vegetation has become established. Silt fences could be constructed around excavation areas and spoil stockpiles to reduce the introduction of fine sediments into adjacent waters. Straw blankets could be placed on exposed road prism slopes during construction to reduce erosion from direct precipitation. Disturbed road prism slopes could be hydroseeded and revegetated with native plants after final grading is completed. Trees that need to be removed during construction should be replaced at a 2: I mitigation ratio. The existing culvert is a corrugated metal pipe with a capacity of approximately 104 cfs and a capacity to convey flows up to the 25 year recurrence (Conditions Report 1995). These flow conveyance estimates made in 1995 may no longer represent the existing condition. Rather, the report predicted that future conditions would degrade to the point that flooding would occur at recurrence intervals closer to the 5-year event as a result of upslope development and sediment deposition in the culvert. The corrugated metal pipe has a diameter of approximately 60 inches with a pitch of approximately l percent. During site visits made in 2007, the culvert flow conveyance capacity was observed to have been diminished as a result of deposition of sand and gravel, concentrated in the downstream end of the pipe. Cabbage Creek, upstream from the culvert, was measured to have a wetted width of approximately 48 inches and a bankfull width of approximately 96 inches. Project Efficacy This project is very conceptual in nature. Site specific survey work and hydraulic modeling would need to be completed to estimate the potential project benefits. There was insufficient data to model potential hydraulic or hydrologic benefits at this time. Qualitatively speaking, reducing sediment loading from this tributary would be expected to help reduce local flooding issues and improve downstream habitat. In addition, improving the passage corridor through Cabbage Creek would permit access to fish habitat present but not regularly accessed above the dysfunctional culvert. Increasing habitat complexity in Cabbage Creek would better enable coho salmon (0. kisutch) and cutthroat trout (0. clarki) to make better use of this Locally Significant Resource Area (LSRA) as identified in the Action Plan (King County 2001). Further investigation into this project would be worthwhile. File No. /079/-005-00 December 19, 2008 Page B-88 GEOENGtNEERS_.@ I II I I fl I I I I I I I I I I I I I I • I I I I I I I I I I I I I I I I I Potential Challenges and Limitations This project is not anticipated to create any significant downstream impacts. The project is located above RM 6.5 on May Creek. Any changes to the movement of water or temporary displacement of substrate or sediment are expected to be dissipated in low-gradient reaches of May Creek in the May Valley. Localized challenges or considerations would include working with landowners to secure the necessary site access and easements, routing traffic during construction, timing construction to avoid or minimize impacts to priority habitat and species. Additional challenges would include securing the necessary funding and permits to complete the work. Additional regulatory constraints may also be imposed on the proposed project due to the fact that much of May Creek in the May Valley was historically forested wetland (Conditions Report, King County 1995) or contains other critical areas. A wetland delineation and critical areas assessment would need to be completed to determine the extent and function of wetland and other habitat features at the site. Any impacts to stream buffers, wetlands and wetland buffers would need to be mitigated if the project were pennitted and implemented. Planning-Level Cost Estimates The proposed project would include the design, permitting and construction of a pre-fabricated, concrete arch or similar structure. The structure would be designed to accommodate flow up to the estimated l 00-year recurrence interval, thereby significantly reducing the frequency of flooding and associated problems at the site. The structure would also be better aligned with the orientation of the existing downstream channel, reducing shear stress, erosion and the need for bank armoring presently required downstream from the existing culvert. The conceptual design illustrated above envisions use of a prefabricated, concrete arch with associated substrate and boulder habitat features proposed for this site. Estimated Construction Costs: $160,200 (See Appendix C for details). Design, construction observation and permitting costs are not included as these costs can vary significantly. Permitting If the culvert replacement project is deemed appropriate for implementation, culvert project design will be completed in accordance with the requirements outlines in the U.S. Army Corps of Engineers (COE) document titled "User's Guide to the Programmatic Consultation for the Removal of Fish Passage Barriers" dated July 29, 2002. This guide represents the first chapter of the COE's "Programmatic Biological Evaluation for Habitat Restoration/Rehabilitation Activities in the State of Washington for Species Listed or Proposed by the National Marine Fisheries Service and U.S. Fish and Wildlife Service under the Endangered Species Act," approved by NOAA Fisheries on May 19, 2002 and the U.S. Fish and Wildlife Service on May 29, 2002. Although no threatened, endangered, or candidate fish species are know to utilize the Cabbage/Country Creek tributary to May Creek, sensitive fish species do utilize the canyon and delta sections of May Creek downstream from May Valley. File No. 1079/-005-00 December 19, 2008 Page B-89 GeoENGINEEIIS .0 At least a portion of the proposed project will be completed below the ordinary high water mark. It is likely, therefore, that the following permits and regulatory compliance steps will be required: o U.S. Army Corps of Engineers (ACOE) Section 404 o Washington State Department of Fish and Wildlife (WDFW) Hydraulic Project Approval, potential consultation with USFWS o Washington State Department of Ecology (Ecology) 401 Water Quality Certification o King County Clearing and Grading Permit o SEPA Checklist, with King County lead o King County Critical Areas Review o Compliance with the King County Shoreline Regulations o WDFW Area biologist and Tribal Consultation Project proponents may qualify for and elect to seek a Section 404 permit from the COE (using programmatic Section 7 consultation procedures as described in the above-referenced documents) and a streamlined Hydraulic Project Approval (HPA) from the Washington Department of fish and Wildlife (WDFW). Under the streamlined HPA process, the culvert project would be exempt from the Washington State Environmental Policy Act (SEPA) and local government permits and fees. File No. I 0791-005-00 December 19, 2008 Page B-90 GEOENGINffRS_g I I I I I I I I I I I I I I I I I I I I I • I I I I I I I I I I I I I I I I PROJECT 26: COUNTRY CREEK CULVERT REPLACEMENT Project 26 is primarily a culvert replacement project, similar to several other projects being proposed in this CRP. There is a more detailed overview for this project, as compared to the majority of the other projects in this Appendix, because additional information was collected at the project site during the pre- design phase. The project is located in close proximity to Project 25, which was proposed for early implementation during the pre-design phase. The added detail is provided for this project, based on the additional work that the project team completed during the predesign process in early 2007. This project was identified as a Category H project during the prioritization process. Site Location Project 26 is located at the intersection of the SE May Valley Road and Country Creek (Tributary 292), approximately 0.2 RM upstream from the confluence of Country Creek with May Creek at RM 6.5. The culvert is located within the NWY.. NEY.. of Section 12, Township 23 N. Range 5 E.,W.M., King County, Washington (Figure 17, Appendix A). Site Description Country Creek drains a portion of the uplands to the north of May Valley known as the Highlands (Conditions Report, King County 1995). The Conditions Report identifies Country Creek as having been altered, to an alignment generally in a south-southeasterly perpendicular to SE May Valley Road. Prior to alteration, Country Creek likely followed a more direct path to its confluence with May Creek. Presently, Country Creek downstream from the culvert under the SE May Valley Road is oriented in an east-west direction, roughly parallel to SE May Valley Road. The Condition Report (King County 1995) describes the Country Creek drainage as having a fairly low gradient ( one to seven percent) across the compound alluvial fan from its confluence with May Creek upstream to approximately RM 0.2. Between RM 0.2 and the road crossing, Country Creek is contained in an artificial channel oriented parallel to SE May Valley Road. Upstream from the culvert, the creek flows through steep bedrock slope with a steep gradient (greater than 15 percent). Country Creek, upstream from the culvert, has been altered resulting in flooding, erosion, habitat degradation and fish passage problems throughout its length (Figure 10, Appendix A). The Country Creek stream channel along the compound alluvial fan downstream from the road crossing has alternating low (I) to high (12) width/depth ratio indicating incision or dredging into the compound alluvial fan. In spite of these alterations, the County/Cabbage Creek drainage is characterized as fairly stable, with relatively little watershed disturbance or risk of worsening conditions in the future (Conditions Report, King County 1995). Lower Country Creek is a relatively stable channel and is considered a Locally Significant Resource Area (LSRA) due to it use by Coho salmons and cutthroat trout for rearing purposes (Action Plan 2001, Conditions Report 1995). This section of creek, however, has been altered and has degraded habitat (see proposed Project 24 ). The existing fiberglass culvert under the SE May Valley Road has a diameter of approximately 40 inches, is approximately 40 feet long, comprised of 3 sections of pipe, with a pitch of approximately 5 percent. During a July 2007 site visit, all flow in Country Creek was passing under the fiberglass culvert and through the road prism rather than through the culvert. Country Creek, upstream from the culvert, was observed to have a confined channel with a stone and mortar armored streambank. Riparian vegetation was primarily horsetail, salmonberry, cultivated shrubs and grass lawn. The upstream channel wetted width was approximately 12 inches, with an estimated bankfull width of 48 inches and bankfull depth of 55 inches. File No. !079/-005-00 Decemher /9, 2008 Page B-91 GEOENGINEERS_B The downstream channel stream-banks were found to be heavily armored with riprap, and covered with vegetation including: hazelnut, maple, salmonberry, blackberry, and reed canarygrass. The Country Creek channel downstream from the culvert was estimated to have a wetted width of 84 inches, a bankfull width of 144 inches, and a bankfull depth of 60 inches. File No. 10791-005-00 December 19, 2008 The existing fiberglass culvert at Country Creek (intake) is heavily armored with rock and mortar with degraded riparian habitat. Page B-91 GEOENGINEER~ I I I I I I I I I i I I I I I I I I • • I I I I I I I I I I I I I I I I The existing 40 inch diameter fiberglass culvert ( outlet) at Country Creek located in the May Valley, Washington. During a June 29, 2007 site visit numerous fish were observed in the pool located downstream of the culvert. Fish were not, however, found upstream of the culvert, nor were they found in the project vicinity a subsequent site visit in July. Project Description Project 26 would replace the dysfunctional culvert on Country Creek to provide some immediate relief to flood, fish passage, and fish habitat problems identified in the Action Plan (King County 200 I). The replacement will be designed in accordance with the stream simulation methodology specified in the WDFW manual titled "Design of Road Culverts for Fish Passage" (Bates 2003). The new structure will be designed to facilitate fish passage and access to an additional 0.24 miles of habitat available above the culvert, up to a natural barrier. The project is also expected to reduce erosion, bank failure and flooding by aligning the channel to orient the stream in the direction of the downstream channel rather than perpendicular. The existing culvert is a fiberglass reinforced pipe with a capacity of approximately 145 cfs and the ability to convey flows up to the I 00-year recurrence (Conditions Report 1995). These flow conveyance estimates made in 1995 may no longer represent the existing condition. The proposed Country Creek File No. 10791-005-00 Decemher 19, 200H Page B-93 GEOENGINEERS.J:j} Culvert Replacement project would include the installation of a bottomless, concrete arch or similar structure to replace the existing culvert. ·i--...=--=·-- Note: W'.ngwe:lt not '1"'3'#11, •./' : .. :, . ,--, """"'""""""""' -CROSS SECTION Conceptual drawing of a pre-cast concrete arch bridge proposed for use at the SE May Valley Road crossing over Country Creek. The proposed project would include the design, permitting and construction of a pre-fabricated, concrete arch or similar structure. The structure would be designed to accommodate flow up to the estimated JOO-year recurrence interval, thereby significantly reducing the frequency of flooding and associated problems at the site. The structure would also be better aligned with the orientation of the existing downstream channel, reducing shear stress, erosion and the need for bank armoring presently required downstream from the existing culvert. Above is a conceptual drawing of a prefabricated, concrete arch with associated substrate and boulder habitat features proposed for this site. The proposed Country Creek Culvert Replacement project includes the installation of a bottomless, concrete arch or similar structure to replace the existing culvert. The replacement culvert will be designed in accordance with the stream simulation methodology specified in the WDFW manual titled "Design of Road Culverts for Fish Passage" (Bates 2003). Stream simulation is a design process for creating natural stream processes within a culvert, with sediment transport, fish passage, flood and debris conveyance within the culvert intended to function as they would in a natural channel. The proposed structure will be located within the footprint of the existing SE May Valley Road prism. The roadway embankments in the vicinity of the wingwalls will require riprap to protect the embankments and wingwalls from scour. The alignment of the proposed culvert may be skewed relative to the existing road prism. Skewing the culvert would shift the outlet towards the orientation (west-flowing) of Country Creek below the culvert, to help reduce flooding and erosion caused by the current orientation of the stream downstream from the File No. 1079/-005-00 December 19, 2008 Page B-94 GeoENGINEER~ I I I I I I I I I I I I I I I I I I I I I • I I I I I I I I I I I I I I existing culvert. This alignment will also reduce the potential for downstream scour. If left uncorrected, higher stream flows through the existing culvert and residual scour of the north bank of the Coxon/Patterson property may necessitate aggressive streambank treatments such as berms and bank armoring to reduce bank erosion. While such action may temporarily address scour and low recurrence flooding problems, such actions would only perpetuate erosion, flooding, fish passage, and fish habitat problems. A new streambed could be constructed inside the proposed culvert. A new channel could be lined with a gravel filter and substrate consisting of rounded gravel, cobbles, and boulders. In addition to protecting the structure and channel from scour and significant degradation, the larger elements of this substrate would create eddies to facilitate the upstream passage of fish. Footings for the proposed culvert would be set far enough below the proposed elevation of the stream channel to provide the necessary bearing capacity for the structure and adequate coverage for unanticipated scour and degradation. Footings would be protected from potential local scour with a layer of riprap. If this project is implemented construction crews should use a variety of Best Management Practices (BMPs) to control erosion and sediment transport throughout construction and continuing until the new vegetation has become established. Silt fences could be constructed around excavation areas and spoil stockpiles to reduce the introduction of fine sediments into adjacent waters. Straw blankets could be placed on exposed road prism slopes during construction to reduce erosion from direct precipitation. Disturbed road prism slopes could be hydroseeded and revegetated with native plants after final grading is completed. Trees that need to be removed during construction should be replaced at a 2: I mitigation ratio. Project Efficacy This project is very conceptual in nature. Site specific survey work and hydraulic modeling would need to be completed to estimate the potential project benefits. There was insufficient data to model potential hydraulic or hydrologic benefits at this time. Qualitatively speaking, reducing sediment loading from this tributary would be expected to help reduce local flooding issues and improve downstream habitat. In addition, improving the passage corridor through Cabbage Creek would permit access to fish habitat present but not regularly accessed above the dysfunctional culvert. Increasing habitat complexity in Cabbage Creek would better enable coho salmon (0. kisutch) and cutthroat trout (0. clarki) to make better use of this Locally Significant Resource Area (LSRA) as identified in the Action Plan (King County 200 I). Further investigation into this project would be worthwhile. Potential Challenges and Limitations This project is not anticipated to create any significant downstream impacts. The project is located above RM 6.5 on May Creek. Any changes to the movement of water or temporary displacement of substrate or sediment are expected to be dissipated in low-gradient reaches of May Creek in the May Valley. Localized challenges or considerations would include working with landowners to secure the necessary site access and easements, routing traffic during construction, timing construction to avoid or minimize impacts to priority habitat and species. Additional challenges would include securing the necessary funding and permits to complete the work. Additional regulatory constraints may also be imposed on the proposed project due to the fact that much of May Creek in the May Valley was historically forested wetland (Conditions Report, King County 1995) or contains other critical areas. A wetland delineation and critical areas assessment would need to be completed to determine the extent and function of wetland and other habitat features at the site. Any File No. /0791-005-00 December 19, 2008 Page B-95 GEOENGINEERS.i impacts to stream buffers, wetlands and wetland buffers would need to be mitigated if the project were permitted and implemented. Planning Level Cost Estimates Estimated Construction Costs: $160,200 (See Appendix C for details). Design, construction observation and permitting costs are not included as these costs can vary significantly. Permitting lfthe culvert replacement project is deemed appropriate for implementation, culvert project design will be completed in accordance with the requirements outlines in the U.S. Army Corps of Engineers (COE) document titled "User's Guide to the Programmatic Consultation for the Removal of Fish Passage Ban'iers" dated July 29, 2002. This guide represents the first chapter of the COE's "Programmatic Biological Evaluation for Habitat Restoration/Rehabilitation Activities in the State of Washington for Species Listed or Proposed by the National Marine Fisheries Service and U.S. Fish and Wildlife Service under the Endangered Species Act," approved by NOAA Fisheries on May 19, 2002 and the U.S. Fish and Wildlife Service on May 29, 2002. Although no threatened, endangered, or candidate fish species are know to utilize the Country Creek tributary to May Creek, sensitive fish species do utilize the canyon and delta sections of May Creek downstream from May Valley. A portion of the proposed project will be completed below the ordinary high water mark. It is likely, therefore, that the following permits and regulatory compliance steps will be required: • U.S. Army Corps of Engineers (ACOE) Section 404 • Washington State Department of Fish and Wildlife (WDFW) Hydraulic Project Approval, potential consultation with USFWS • Washington State Department of Ecology (Ecology) 40 l Water Quality Certification • King County Clearing and Grading Permit o SEPA Checklist, with King County lead • King County Critical Areas Review • Compliance with the King County Shoreline Regulations • WDFW Area biologist and Tribal Consultation Project proponents may qualify for and elect to seek a Section 404 permit from the COE (using programmatic Section 7 consultation procedures as described in the above-referenced documents) and a streamlined Hydraulic Project Approval (HPA) from the Washington Department of fish and Wildlife (WDFW). Under the streamlined HPA process, the culvert project would be exempt from the Washington State Environmental Policy Act (SEPA) and local government permits and fees. File No. /0791-005-00 Decemher 19, 2008 Page B-96 GEOENGINEERS _9 I I I I I i I fi I . I I I I I I I I I I I I I •• I I I I PROJECT 27: COUNTY-CABBAGE CREEK CULVERT REPLACEMENT Project 27 is primarily a culvert replacement project, similar to several other projects being proposed in this CRP. There is a more detailed overview for this project, as compared to the majority of the other projects in this Appendix, because additional information was collected at the project site during the pre- design phase. The project is located in close proximity to Project 25 and 26. Project 25 was proposed for early implementation during the pre-design phase. The added detail is provided for this project, based on the additional work that the project team completed during the predesign process in early 2007. This project was identified as a Category H project during the prioritization process. Site Location This project is located approximately 150 feet downstream from the confluence of County and Cabbage Creeks near the intersection of the SE May Valley Road and Country Creek (Tributary 292). The project is approximately 0.2 RM upstream from the confluence of Country Creek with May Creek at RM 6.5. The culvert is located within the NW'/.i NE'/.i of Section 12, T 23 N. R 5 E.,W.M. in King County, Washington (Figure 17, Appendix A). Site Description Country and Cabbage Creeks drain a portion of the uplands to the north of May Valley known as the Highlands (Conditions Report, King County 1995). The Condition Report describes the Country Creek drainage as having a fairly low gradient (one to seven percent) across the compound alluvial fan from its confluence with May Creek upstream to approximately RM 0.2. Between RM 0.2 and the road crossing, Country Creek is contained in an artificial channel oriented parallel to SE May Valley Road. The Country Creek stream channel along the compound alluvial fan downstream from the road crossing has alternating low (1) to high (12) width/depth ratio indicating incision or dredging into the compound alluvial fan. In spite of these alterations, the County/Cabbage Creek drainage is characterized as fairly stable, with relatively little watershed disturbance or risk of worsening conditions in the future (Figure IO, Appendix A). Lower Country Creek is a relatively stable channel and is considered a Locally Significant Resource Area (LSRA) due to it use by Coho salmons and cutthroat trout for rearing purposes (Action Plan 2001, Conditions Report 1995). This section of creek, however, has been altered and has degraded habitat (sec proposed Project 24). A private driveway over Country Creek provides landowners access to that portion of the May Valley located south of the SE May Valley Road, as well as County and Cabbage Creeks. There is an existing 50-inch diameter smooth concrete culvert that is approximately 20 feet long, with a 12 inch smooth concrete overflow culvert located on the south side of the 50 inch culvert. The upstream channel wetted width was approximately 60 inches, with an estimated bankfull width of 240 inches and bankfull depth of 72 inches . The downstream end of the 50 inch concrete culvert include a corrugated metal pipe culvert has been crushed by excessive force applied to a poorly designed road bed and prism around the culvert. The Country Creek channel downstream from the partially crushed corrugated metal pipe culvert was found to have a riparian streambank dominated by blackberry with an estimated wetted width of 120 inches, bankfull width of 360 inches, and bankfull depth of 96 inches. Together, these structures serve as the creek crossing. Country Creek upstream the concrete culvert intake was observed to be heavily armored and densely vegetated with hardtack, blackberry, and salmonberry. File No. 10791-005-00 December 19, 2008 Page B-97 GEOENGINEERS g File No. I 0791-005-00 December J 9, 2008 The existing 50 inch smooth concrete culvert (intake) at Country Creek located in the May Valley, Washington. The existing fiberglass culvert at Country Creek (outlet) is heavily armored with rock and mortar with degraded riparian habitat. Page B-98 GeoENGIN!ER~ I I I !i '11 I I I I I I I I I I I I I I I I I I I I I I I Project Description Project 27 would replace the dysfunctional culvert on Country Creek to provide some immediate relief to flood, fish passage, and fish habitat problems identified in the Action Plan (2001 ). The replacement will be designed in accordance with the stream simulation methodology specified in the WDFW manual titled "Design of Road Culverts for Fish Passage" (Bates 2003). The new structure will be designed to facilitate fish passage and access to an additional 0.24 miles of habitat available above the culvert, up to a natural barrier. The project is also expected to reduce erosion, bank failure and flooding by aligning the channel to orient the stream in the direction of the downstream channel rather than perpendicular. The proposed Country Creek Culvert Replacement project includes the installation of a bottomless, concrete arch or similar structure to replace the existing culvert. The replacement culvert will be designed in accordance with the stream simulation methodology specified in the WDFW manual titled "Design of Road Culverts for Fish Passage" (Bates 2003). Stream simulation is a design process for creating natural stream processes within a culvert, with sediment transport, fish passage, flood and debris conveyance within the culvert intended to function as they would in a natural channel. The proposed structure will be located within the footprint of the existing road prism providing access to private lands south of the SE May Valley Road and the County/Cabbage Creek drainages. The roadway embankments in the vicinity of the wingwalls will require riprap to protect the embankments and wingwalls from scour. -= \, ™ ™ .....-.. .. ~-- .•... '\ .. •,. •--. fllti:IM1'1'1,11! ''""'" """""_,, '"""" ~ CROSS SECTION Conceptual drawing of a pre-cast concrete arch bridge that could be used in place of the existing culvert passing Country Creek under a private drive. The culvert will be aligned to minimize the potential for downstream scour. If left uncorrected, higher stream flows through the existing culvert and residual scour of the north (right) bank may undermine the SE May Valley Road, and the south (left) bank would erode private property. Such erosion would necessitate aggressive streambank treatments such as berms and bank armoring to reduce bank erosion, particularly to avoid failure of the SE May Valley Road. While such streambank protection action may File No. !0791-005-00 Decemher 19, 2008 Page B-99 GeoENGINEERS_g temporarily address scour and low recurrence flooding problems, such actions would only perpetuate existing erosion, flooding, fish passage, and fish habitat problems in the area. A new streambed could be constructed inside the proposed culvert. A new channel could be lined with a gravel filter and substrate consisting of rounded gravel, cobbles, and boulders. In addition to protecting the structure and channel from scour and significant degradation, the larger clements of this substrate would create eddies to facilitate the upstream passage of fish. Footings for the proposed culvert would be set far enough below the proposed elevation of the stream channel to provide the necessary bearing capacity for the structure and adequate coverage for unanticipated scour and degradation. Footings would be protected from potential local scour with a layer ofriprap. If this project is implemented construction crews should use a variety of Best Management Practices (BMPs) to control erosion and sediment transport throughout construction and continuing until the new vegetation has become established. Silt fences could be constructed around excavation areas and spoil stockpiles to reduce the introduction of fine sediments into adjacent waters. Straw blankets could be placed on exposed road prism slopes during construction to reduce erosion from direct precipitation. Disturbed road prism slopes could be hydroseeded and revegetated with native plants after final grading is completed. Trees that would need to be removed on the south (left) bank of Country Creek construction should be replaced at a 2: I mitigation ratio. Project Efficacy This project is very conceptual in nature. Site specific survey work and hydraulic modeling would need to be completed to estimate the potential project benefits. There was insufficient data to model potential hydraulic or hydrologic benefits at this time. Qualitatively speaking, reducing sediment loading from this tributary would be expected to help reduce local flooding issues and improve downstream habitat. In addition, improving the passage corridor through Cabbage Creek would permit access to fish habitat present but not regularly accessed above the dysfunctional culvert. Increasing habitat complexity in Cabbage Creek would better enable coho salmon (0. kisutch) and cutthroat trout (0. clarki) to make better use of this Locally Significant Resource Area (LSRA) as identified in the Action Plan (King County 200 I). Further investigation into this project would be worthwhile. Potential Challenges and Limitations This project is not anticipated to create any significant downstream impacts. The project is located above RM 6.5 on May Creek. Any changes to the movement of water or temporary displacement of substrate or sediment are expected to be dissipated in low-gradient reaches of May Creek in the May Valley. Localized challenges or considerations would include working with landowners to secure the necessary site access and easements, routing traffic during construction, timing construction to avoid or minimize impacts to priority habitat and species. Additional challenges would include securing the necessary funding and permits to complete the work. Much of May Creek in the May Valley was historically forested wetland (Conditions Report, King County 1995) or contains other critical areas. A wetland delineation and critical areas assessment would need to be completed to determine the extent and function of wetland and other habitat features at the site. Any impacts to stream buffers, wetlands and wetland buffers would need to be mitigated if the project were permitted and implemented. File No. 1079/-005-00 December I 9, 2008 Page B-/00 GEOENGtNEER~ I I I I I I I I I I I I I I I I I I I I I I I I I Planning Level Cost Estimates Estimated Construction Costs: $160,200 (See Appendix C for details). Design, construction observation and permitting costs are not included as these costs can vary significantly. Permitting If the culvert replacement project is deemed appropriate for implementation, culvert project design will be completed in accordance with the requirements outlines in the U.S. Army Corps of Engineers (COE) document titled "User's Guide to the Programmatic Consultation for the Removal of Fish Passage Barriers" dated July 29, 2002. This guide represents the first chapter of the COE's "Programmatic Biological Evaluation for Habitat Restoration/Rehabilitation Activities in the State of Washington for Species Listed or Proposed by the National Marine Fisheries Service and U.S. Fish and Wildlife Service under the Endangered Species Act," approved by NOAA Fisheries on May 19, 2002 and the U.S. Fish and Wildlife Service on May 29, 2002. Although no threatened, endangered, or candidate fish species are know to utilize the Cabbage/Country Creek tributary to May Creek, sensitive fish species do utilize the canyon and delta sections of May Creek downstream from May Valley. At least a portion of the proposed project will be completed below the ordinary high water mark. It is likely, therefore, that the following permits and regulatory compliance steps will be required: • U.S. Army Corps of Engineers (ACOE) Section 404 o Washington State Department of Fish and Wildlife (WDFW) Hydraulic Project Approval, potential consultation with USFWS • Washington State Department of Ecology (Ecology) 401 Water Quality Certification • King County Clearing and Grading Permit • SEPA Checklist, with King County lead • King County Critical Areas Review • Compliance with the King County Shoreline Regulations • WDFW Arca biologist and Tribal Consultation Project proponents may qualify for and elect to seek a Section 404 permit from the COE (using programmatic Section 7 consultation procedures as described in the above-referenced documents) and a streamlined Hydraulic Project Approval (HPA) from the Washington Department of fish and Wildlife (WDFW). Under the streamlined HPA process, the culvert project would be exempt from the Washington State Environmental Policy Act (SEPA) and local government permits and fees. File No. 1079/-005-00 December 19, 200R Page B-/0/ GEOENGINHIISg PROJECT 28: WETLAND HABITAT ENHANCEMENT PROJECT {WSDQT SOUTH) Project 28 would require the removal of reed canarygrass and the construction of a wetland pond and buffer area on the right (north) bank of May Creek (Figure B-28). The purpose of the project would be to attenuate floodwater and sediment in May Creek. This project was identified as a Category G project during the prioritization process. Site Location Project 28 is located adjacent to May Creek between RM 6.75 and RM 6.95 (Figure 18, Appendix A). The site is located on the left (south) bank on a parcel owner by the Washington Department of Transportation (WSDOT). Site Description The proposed project is approximately 8.4 acres in area. Based on the Conditions Report (King County 1995), landuse changes in the area eliminated the forested wetland likely historically present at the site. The site is a degraded wetland on the south (left) bank of May Creek primarily vegetated with reed canarygrass and willow. The area is presently open space and residential area with limited use. May Creek is an open, flowing channel in the project area (Figure I 0, Appendix A). Project Description This project would create a forested wetland complex, buffer area, and enhanced riparian corridor adjacent May Creek. The wetland would be designed to help assimilate high flows and sediment loads in May Creek. The riparian area would be restored to help maintain effective flows and sediment transport processes. The existing May Creek channel would not be modified. These actions would help reduce flooding and sediment deposition in May Creek by improving flow and sediment conveyance. This project would help protect upstream fish passage. The improved riparian and wetland areas will also provide better fish habitat. The new corridor would improve fish passage upstream. This project would also improve water temperatures by increasing conveyance and providing full channel shading. Project Efficacy This Project would seek to re-create a forested wetland buffer area on the left bank side of May Creek immediately downstream of the Renton-Issaquah Highway (SR 900). The site is 2.97 acres and extends 950 feet lengthwise in the longitudinal direction and has 200 feet of width in the perpendicular direction to May Creek streamflow. It was modeled with standard wetland enhancement modeling procedures established in this analysis. The project begins approximately 350 feet downstream of culvert underneath SR 900. Model results indicate that the water surface elevation will drop approximately 0.2 feet for the 2-year flood event, possibly alleviating some flooding problems. Modeling results indicate channel velocities will decrease from 2.48 ft/s to 1.79 ft/s for the 150 cfs flow. Hydraflow modeling results indicate that site runoff from the 2-year precipitation event decrease from 0.32 cfs to 0.145 cfs a 55 percent decrease. In summary, proposed Project 28 would provide some level of flood relief. In addition, the project would enhance approximately 44,000 square feet of riparian buffer area, 33, I 00 square feet of wetland, and 96,200 square feet of enhanced wetland buffer area. File No. 1079/.005·00 December 19, 2008 Page B-102 GEOENGINEE~ I I I . I I II I I I I I I I ii '.I . I I I I I I I I ,_ " ,_ " \:! I >-- ~ ~ :. L, "' I N u l "' I ;;,; t I. "' C.) " m Is ,_ 0 I iii .ll E 0 u ~ 1: g 9 "' g '" ,_ 0 I "' 0 "' lil ll:'. I I C, I' ,, ' I . I t ', ' , . ' ~ ~., ...... Existing Conditions Conceptual Drawing of Wetland and Riparian Restoration Area GeoENGINEER~ Conceptual Drawing Project 28 FIGURE 8'25 Eartb Stiet1Ce + Ttc:Jmolop File No. }079/-005-00 December 19, 2008 Page 8-103 GeoENGINEERS _,t;' i i; I'! '1i ! l'ii w ~· f 5 ~ O· .... 0 !<I .8 J ~ g • Existing Conditions Conceptual drawing of detention basins In i';:t-----------------------------1 Conceptual Drawing P'roji!ct i~ ,,. n "' 0 w "' GeoENGINEER~ £.nUl-$clcm::a + TrctmllDIO File No. 1079/-005-00 December J 9, 2008 l=IGURE B26 Page B-106 GEOENGINHIIS.i @. liH ~ \ \ • I I I I I I I I I I I I I I I I I I I PROJECT 29: DETENTION PROJECT-NORTH FORK MAY CREEK (WSDOT EAST) Project 29 is primarily a stormwater detention project located on the right (north) bank of the North Fork of May Creek (Figure B-29). The purpose of the project would be to attenuate floodwater and sediment being transported to May Creek via the North Fork of May Creek. This project was identified as a Category L project during the prioritization process. Site Location Project 29 is located on the North Fork of May Creek, between RM 7.02 and RM 7.15 (Figure 18, Appendix A). The proposed project is located immediately upstream from the SR-900 bridge crossing May Creek. Site Description The project is approximately 4.75 acres in area. The area is presently open space with little apparent use (Figure 11, Appendix A). The North Fork of May Creek bisects the site and is an open, flowing channel with a reasonable mix of sediment particle types, habitat complexity and woody debris. Habitat in this section of channel appears to be functioning reasonably well. The North Fork of May Creek exhibits a moderate gradient, and the stream channel has a hard bottom of mixed sands and gravels. Project Description The existing ground in the vicinity of Project 29 acts as a natural detention feature. This project proposes expanding this natural detention feature, while creating some adjacent habitat in the area. This project would create two high-flow detention basins configured as bioswalcs or similar structures. The basins would be designed to help assimilate high flows and sediment loads for the North Fork May Creek. The riparian area would be improved to help maintain effective flows and sediment transport processes. The existing May Creek channel would not be modified. These actions would help reduce flooding and sediment deposition in May Creek by improving flow and sediment conveyance. This project would directly improve riparian habitat through the enhancement of these habitat features. This project would also improve water temperatures by providing dense riparian vegetation adjacent the channel. Project Efficacy Hydraflow was utilized to make some simple estimates of geometric changes to the land topography in this area and the anticipated changes in storage volume if the existing ground were excavated to some extent to create the detention features. The scenario was modeled by assuming the square footage of the existing detention evident on the aerial GIS photograph (Figure 18, Appendix A). The existing north detention feature was measured to be approximately 75 x 75 feet with a depth of three feet and 5: I side slopes, the new geometry of this feature was estimated from the design drawings to be 150 x JOO feet excavated to 6-feet of depth with 5: I side slopes. The existing south detention feature was measured to be approximately 60 x 60 feet with 5:1 side slopes and an assumed bottom depth of three feet, the new geometry of this feature was estimated from the conceptual design drawings to be 85 x 85 feet with 5: I side slopes and excavated to six feet of depth. These geometric changes would provide 181,000 cubic feet of additional storage, and 223,000 cubic feet of storage overall. This storage capacity is approximately I percent of the measured discharge on May Creek for a storm with a five day duration and a peak discharge of 77 cfs. Hydrologic routing was performed for this detention basin. Results of this analysis indicate that this detention basin will have minimal flood-wave attenuation impacts on frequent flooding events. This is due to the long-duration steady inflow of the upstream hydrographs and the relatively small size of the proposed storm water detention feature. File No. 10791-005-00 December 19, 2001'/ Page B-105 GEOENGINEERS _g ·•:la ;' .,,, ,,, i' , I -. Existing Conditions Conceptual .drawing of detention basins GeoENGINEER~ 1t1nn-1cl~~ce • Tlrd::IRIIUD l'IGURE 826 File No. J 079 J-005-00 December 19, 2008 Page B-106 GEOENGINEER~ I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 'I I I In summary, the project may provide some localized stormwater flood control but would not substantially mitigate downstream flooding issues. Potential Challenges and Limitations A significant area of land would be converted to the retention area. It is unknown if these actions would be of interest to the Washington Department of Transportation, on who's property the project would be located. In the Action Plan (200 I) this site may have been identified as remnant forested wetland. If the site is, indeed, remnant forested wetland it would not be appropriate to construct detention basins or other structures. A wetland delineation would be completed to detennine if this is a remnant forested wetland. This project would disturb well over I acre of area, necessitating additional permitting and regulatory considerations. Any impacts to stream buffers, wetlands and wetland buffers would need to be mitigated if the project were permitted and implemented. Planning-Level Cost Estimates Estimated Construction Costs: $345,900 (See Appendix C for details). Design, construction observation and pennitting costs are not included as these costs can vary significantly. Permitting A portion of the work will be completed below the OHWM and will require placing fill into a critical area, the following permits and approvals likely will be required: • U.S. Army Corps of Engineers {ACOE) Section 404 • Washington State Department of Fish and Wildlife (WDFW) Hydraulic Project Approval • Washington State Department of Ecology (Ecology) 40 l Water Quality Certification • King County Clearing and Grading Permit • SEPA Checklist, with King County lead • King County Critical Areas Review • Compliance with the King County Shoreline Regulations • Tribal and WDFW area biologist consultation This project would disturb over I acre of ground. As a result, additional permit would be required, including ACOE Section 404 project-specific permitting and requirements under Ecology's National Pollutant Discharge Elimination System (NPDES), securing a Construction Stormwater General Permit. File No. J079/-0n5-00 Decemher 19, 2008 Page B-107 GeoENGINEER~ PROJECT IFP1: INEFFECTIVE FLOW PROJECT 1 -2870 TO INDIAN MEADOW CREEK Project IFP I treats ineffective flow areas within the mainstem channel from 2870/E to Indian Meadow Creek using direct channel modifications of the stream cross-section and channel profile. The project uses mechanical methods to create a positive channel slope where the channel currently exhibits extremely flat and/or negative slopes (Figure IFP l, see Conceptual Channel Profile insert). The purpose of the project is to increase water and sediment conveyance through the channel, thereby reducing the duration of flooding and improving fish passage. This project was identified as a Category E project during the prioritization process. Site Location Project IFP l is located on the mainstem May Creek between RM 4.28 and RM 4.89 (Figure 14, Appendix A), between the 287D/E and Indian Meadow Creek confluence areas. The segment of creek to be treated begins approximately 0.1 RM downstream from the !48'h Avenue SE bridge and includes the mainstem May Creek throughout a reach extending upstream approximately 3,200 feet to a point just upstream from the confluence of May Creek and Indian Meadow Creek. This project intersects, or runs adjacent to, Projects 4, 5, 6, 7, 8, I 0, 11, and 12 (Figure 14, Appendix A). Site Description This project is located in the upper-most portion of Reach l and the lowermost portion of Reach 2. The upper portion of the site is currently used as horse pasture and the lower portion of the site is open space. It is reported in the Conditions Report (King County 1995) that landuse changes in the area included elimination of a conifer and deciduous-based forested wetland likely historically present at the site. A portion of the wetland is still present at the site (see Figure 5, Appendix A); however, the existing remnant wetland is dominated by reed canarygrass and willow with limited other wetland or riparian species. The section of May Creek flowing through the wetland has minimal flow and sediment conveyance capacity as the result of ongoing sediment deposition and encroachment of reed canarygrass in the channel. Although this area no longer functions as a forested wetland, it does still provide some value in terms of flood attenuation, nutrient assimilation, and habitat value in its degraded condition (see Figure 6 and 7, Appendix A). Recent preliminary hydraulic modeling completed by OTAK (2006) as part of this project revealed areas of ineffective flow in this reach of May Creek, suggesting that issues identified in the Action Plan can be expected to persist unless addressed. This ineffective flow area can be attributed to slow flow velocities (average 1.4 ft/sec) and the accumulation of sediment within the channel upstream of bridge constrictions and crossings. Project Description This project would address ineffective flow and fish passage barrier issues along an approximately 3,220 foot section of May Creek. Ineffective flows would be addressed through the mechanical manipulation of the channel cross-section area and longitudinal profile (Figure IFP I). Sediment and vegetation would be mechanically removed from the channel to create a more uniform longitudinal stream profile throughout the site, providing a relatively uniform channel bottom width, and reducing roughness in the channel by removing all encroaching vegetation. Based on measurements of reference reaches along May Creek where flows were found to be effective, the average channel bottom width was determined to be 15-feet with 1.5:1 (horizontal:vertical) side slopes. This project would recreate a channel bottom width and side slopes to match the reference reach File No. I 0791-005-00 December 19, 2008 Page B-108 GeoENGINEE~ I I 1. I I I •• I I I I I I I I I I I I I I I I I channel dimensions. As a result, implementation of IFPI would establish an overall positive channel slope of 0.0011. This would replace a channel longitudinal profile that currently exhibits extremely flat and negative slopes for the majority of the segment length . A typical proposed cross section is illustrated on Figure IFP I (see Conceptual Cross Section insert). Channel side slopes will be recreated at a 1.5:1 (horizontal:vertical), up to the point of intersection with the existing floodplain. By constructing the channel side slopes in this manner the area disturbance would be minimized, floodplain fill would be avoided, and the design would aid in vegetation retention. During the redefining of this channel most of the instrcam vegetation will be removed. It is also recommended that vegetation be removed approximately within 5 feet of both the left and right channel banks during construction of this project. Project Efficacy If IFP 1 were implemented, the channel profile would be more uniform to promote better downstream conveyance of both water and sediment. The removal of in-channel vegetation would also benefit the project by reducing choking and blocking of the channel, while also improving fish passage conditions. The proposed project would increase overall channel velocity and in-channel conveyance and would reduce frequent bank overtopping and broad, shallow flooding during high recurrence events. The project may also reduce water temperatures, improve sediment conveyance, and provide more suitable stream habitat for fish and wildlife. Geo Engineers used HEC-RAS hydraulic models developed by OT AK (OT AK 2006) to evaluate the efficacy of IFP l. The evaluation was based on a conceptual project design as described in the project description section above. Based on modeling results this project would be expected to help mitigate the ineffective flow area in this segment. As described in the main body of the Conceptual Restoration Plan, IFP I would improve the ineffective flow ranking from an overall ranking of 3.6 (moderate ineffective flow) down to a ranking of 2.4 (average ineffective flow). This project would also help alleviate the. flooding of May Creek in the direct vicinity of the project. During 2-year flows the in-channel conveyance would be expected to increase from 49 to 89 percent. This means that less water would overlap the channel banks. Another hydraulic benefit of this project is that. it would increase flow velocities from 1.4 ft/sec to 2.0 ft/sec which would help convey more sediment through the segment and reduce the ability of vegetation to re-grow within the channel. The project benefits just described are based on model results of conditions immediately following implementation of the project. As IFP I does not address upslope sediment loading and hydrologic issues, the benefits of IFP I would be expected to decrease over time, as the May Creek channel would be expected to infill with sediment and reed canarygrass over time. Several other projects are proposed for implementation in the area of!FP I that would complement IFP I. Projects 4, 5, 6, 7, 8, 10, 11, and 12 are all located in the vicinity of IFP I, and include elements of riparian and wetland enhancement that would better address long-term, river process issues in the reach. Therefore, the short-term benefits of IFP 1 reducing flood duration, sedimentation and habitat degradation would be prolonged through the concurrent implementation of other projects in the vicinity of!FP I. File No. /0791-005-00 Deccmhcr /9, 2008 Page B-109 GtoENGINEE~ I I I I I I I I I I I I I I g • I m ll g " ~ I § 0 0 ,; 0 0 ~ ' 0 I 6 " ~ • I ~ E ll I ~ Conceptual Channel Profile: IFP 1 Conceptual Cross Section: IFP 1 (RM 4.485) 310 310 - 309 ----------. --. -. -------------------------. . 308 ~-309 307 !:. 306 C: :!l 305 .. > _gi 304 w 303 :>,/~ ,,A. --------I • I f-'" 308 g il; 307 iii 306 305 302 304 301 25 35 45 300 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 5 --Existing Ground River Station (miles) --Proposed Ground -Existing Ground -Proposed Ground Reference: USGS EOC Ortho Urban aerial photos provided by the USGS Seamless data server. The May Creek stream layer and roads were provided by King County . Notes: 55 65 75 85 Feet •••. Existing 2yr Water Surface ••• , Proposed 2yr Water Surface 1. The locations of a11 features shown are approximate. 2. This drawing is for infomation purposes. tt is intended to assist in showing features discussed in an attached document. GeoEngineers, Inc. can not guarantee the accuracy and content of electronic files. The master file is stored by GeoEngineers, Inc. and will serve as the official record oth this communication. 95 /, 7 . • . "'!ft·-::::;;..,.,.~-m-~, a....__, ...... . '. ... -~~ v.,,...,_~. t. --., )i r ·. . . . ~J'.?',f"; ~-. . . p.' '· . '. ' .. ~>: .1Pl_ · 1·. ~-~!J_.' r· 0-"' . /. ·J \, ' ,,, .,, ..... : '.",., ... ~ . ,.,~ :n"" . _,. . ·' . \~). .. : "' • ""_ ~ r '-:'c.Q ., . 0 1-~"iv, ~ :.,.~~ [. ~·--.;....;. V ~--. " -~--;-·~1 A".~· ••• ~.,.. ,;'.'.; ~ ,~ ,, j • ~ .. , '>::-,~ " J • '-__:': <'; 1 J:" y~~. i......~.:Ji'! ' ~fl . :.~- o• ,.;., • .. < ..... "" Map Legend Project Length Roads May Cr. / River Mile (RM) :~ 200 0 Feet Conceptual Drawings Ineffective Flow Project 1 (IFP 1) 200 I May Creek, King County, Washington I I GeoENGII\IEER~ Figure IFP 1 I I I I I I I I I I I I I I I I I I I Potential Challenges and Limitations The single greatest challenge and limitation to IFP I is the ephemeral nature of the solution proposed. While IFP I would be expected to immediately address flood duration, conveyance, fish passage, and other issues, the benefits would be expected to be short-lived. Improvements made to channel performance through the mechanical manipulation of channel cross-section and profile would be expected to degrade over time as each runoff event conveys new sediment into the May Valley. As the May Valley is naturally a sediment deposition zone, and as sediment sources in the headwaters of the May Valley remain unmitigated, May Creek would be expected to fill back in. Therefore, the implementation of !FP I, absent any other action, would not be expected to serve a long-term solution to the flood duration, sedimentation, fish passage, or other issues in this section of May Creek. Unless this project is augmented by upstream and perhaps downstream solutions offered in Projects I through 29 and through implementation of stormwater and sediment control solutions in May Valley headwaters areas, the short- term flooding and fish passage benefits realized through implementation of IF Pl will be lost. Another potential challenge to implementation of this project is the need to work with a large number of private landowners and land managers to fully implement project IFP I. The project encompasses a reach of May Creek approximately 3,200 feet long. The project would need to be implemented throughout this length for expected benefits to be realized. Landowners must grant permission for these projects to be implemented. It is unknown if these actions would be of interest to the landowners. Another challenge to this project is the fact that a large amount of channel would be disturbed below the Ordinary High Water Mark (OHWM). The proposed removal of silty substrate and vegetation from within the channel would be expected to cause concern among regulatory agencies, including WDFW and the Tribes. Additional regulatory constraints may be imposed on the proposed project due to the fact that much of May Creek in the May Valley was historically a forested wetland (Conditions Report, King County 1995), and continues to maintain wetland and other critical habitat functions in its present, degraded condition. Wetland delineation would need to be completed to detennine the extent of wetland features at the site. Any impacts to stream buffers, wetlands and wetland buffers would need to be mitigated if the project were permitted and implemented. Planning-Leve/ Cost Estimates Estimated Construction Costs: $179,700 (See Appendix C for details). Design, construction observation and permitting costs are not included as these costs can vary significantly. Permitting The majority of the project would involve work below the OHWM and will require placing fill into a critical area, the following permits and approvals likely will be required: • U.S. Army Corps of Engineers (ACOE) Section 404 • Washington State Department of Fish and Wildlife (WDFW) Hydraulic Project Approval • Washington State Department of Ecology (Ecology) 401 Water Quality Certification • King County Clearing and Grading Permit • SEPA Checklist, with King County lead • King County Critical Areas Review o Compliance with the King County Shoreline Regulations • Tribal and WDFW area biologist consultation This project would disturb over I acre of land. As a result, additional permits would be required, including an ACOE Section 404 project-specific permit, a Construction Stormwater General Permit and permits required under Ecology's National Pollutant Discharge Elimination System (NPDES). File No. 1079/-005-00 December 19, 2008 Page B-111 GEOfNGINEERS _@ PROJECT IFP 2: INEFFECTIVE FLOW PROJECT 2 · UPPER COLASURDO PASTURE Project IFP 2 treats ineffective flow areas within the mainstem channel of May Creek by creating an overall positive channel slope where the channel currently exhibits extremely flat and negative slopes. The project uses mechanical methods to create a positive channel slope where the channel currently exhibits extremely flat and/or negative slopes (Figure IFP 2, see Conceptual Channel Profile insert). The purpose of the project is to increase water and sediment conveyance through the channel, thereby reducing the duration of flooding and improving fish passage. This project was identified as a Category E project during the prioritization process Site Location Project number IFP 2 is located on the mainstem May Creek between RM 5.05 and RM 5.3 (Figure 14, Appendix A). The proposed project reach is generally located between the upper-most private bridge located on the Colasurdo property and a point just upstream from the eastern-most Colasurdo fence line, a distance of approximately 1,320 feet. This ineffective flow project runs adjacent to Projects 13 and 14 (Figure 14, Appendix A). Site Description This project is located in the upstream-most portion of Reach 2 and a small portion of Reach 3. The site traverses a wetland (see Figure 5, Appendix A) and is currently used primarily as horse pasture. It is reported in the Conditions Report (King County 1995) that historic landuse in the area eliminated a previously existing conifer and deciduous-based forested wetland at the site. A portion of the wetland is still present at the site (see Figure 5, Appendix A); however, the existing remnant wetland is dominated by reed canarygrass and willow with limited other wetland or riparian species. The section of May Creek flowing through the wetland has minimal flow and sediment conveyance capacity as the result of ongoing sediment deposition and encroachment of reed canarygrass in the channel. Although this area no longer functions as a forested wetland, it does still provide some value in terms of flood attenuation, nutrient assimilation, and habitat value in its degraded condition (see Figure 7, Appendix A). Recent preliminary hydraulic modeling completed by OTAK (2006) as part of this project revealed areas of ineffective flow in this reach of May Creek, suggesting that issues identified in the Action Plan can be expected to persist unless addressed. This ineffective flow area can be attributed to slow flow velocities ( average 1.4 ft/sec) and the accumulation of sediment within the channel upstream of bridge constrictions and crossings. Project Description This project would address ineffective flow and passage barrier issues in an approximately 1,320 foot section of May Creek. Ineffective flows would be addressed through the mechanical manipulation of the channel cross-section area and longitudinal profile (Figure IFP 2). Sediment and vegetation would be mechanically removed from the channel to create a more uniform longitudinal stream profile throughout the site, providing a relatively uniform channel bottom width, and reducing roughness in the channel by removing all encroaching vegetation. Based on measurements of reference reaches along May Creek where flows were found to be effective, the average channel bottom width was determined to be 15-feet with 1.5: I (horizontal:vertical) side slopes. This project would recreate a channel bottom width and side slopes to match the reference reach channel dimensions. As a result, implementation of IFP 2 would establish an overall positive channel File No. 10791-005-00 December 19, 2008 Page B-112 GeoENGINEERS..@ I I I I I I I I I I I I I I I I I I I I I I I I I slope of 0.0005. This would replace a channel longitudinal profile that currently exhibits negative slopes for the majority of the segment length intermixed with short steep sections. A typical proposed cross section is illustrated on Figure IFP-2 (see Conceptual Cross Section insert). Channel side slopes will be.recreated at a 1.5: I (horizontal:vertical), up to the point of intersection with the existing floodplain. By constructing the channel side slopes in this manner the area of disturbance would be minimized, floodplain fill would be avoided, and the design would aid in vegetation retention. During the redefining of this channel most of the instream vegetation will be removed. It is also recommended that vegetation be removed approximately within 5 feei of both the left and right channel banks during construction of this project. Two other projects are proposed in the vicinity of project IFP 2. One project, Project 13, proposes to enhance riparian habitat and wetland buffer along the south (left) bank adjacent a portion of IFP 2. Such a project may well provide for the need to remove vegetation from the 5 feet adjacent the stream bank in this section of the project, if IFP 2 is implemented. Some form of vegetated buffer will be necessary to delay any necessary routine maintenance to control vegetation within the channel for the first few years. Project Efficacy If IFP .2 were implemented, the channel profile would be more unifonn to promote better downstream conveyance of both water and sediment. The removal of in-channel vegetation would also benefit the project by reducing choking and blocking of the channel, while also improving fish passage conditions. The proposed project would increase overall channel velocity and in-channel conveyance and would reduce frequent bank overtopping and broad shallow flooding during high recurrence events. The project may also reduce water temperatures, improve sediment conveyance, and provide more suitable stream habitat for fish and wildlife. GeoEngineers used HEC-RAS hydraulic models developed by OTAK (OTAK 2006) to evaluate the efficacy of IFP 2. The evaluation was based on a conceptual project design as described in the project description section, above. Based on modeling results this project would be expected to help mitigate the ineffective flow area in this segment. As described in the main body of the Conceptual Restoration Plan, IFP 2 would improve the ineffective flow ranking from an overall ranking of 3.2 (moderate ineffective flow, down to a ranking of2.4 (average ineffective flow). It should be noted, however, that the improved ranking was calculated based on the assumption that IFP I would be implemented at the same time. This project would also help alleviate the flooding of May Creek in the direct vicinity of the project. During the 2-year flows the in-channel conveyance would increase from 73 to 91 percent which means that less water would overlap channel banks. Another hydraulic benefit of this project is that it would slightly increase velocities from I. 7 ft/sec to 1.9 ft/sec which would help convey more fine sediment through the reach and help reduce the re-growth of vegetation within the channel. The project benefits just described arc based on model results of conditions immediately following implementation of the project. As IFP 2 does not address upslope sediment loading and hydrologic issues, the benefits of IFP 2 would be expected to decrease over time, as the May Creek channel would be expected to infill with sediment and reed canarygrass over time. Other projects proposed for implementation in the vicinity of this area would complement IFP 2, including elements of riparian and wetland enhancement, that would better address long-term, river process issues in the reach. Therefore, the short-term benefits of IFP 2 reducing flood duration and enhancing fish passage throughout the reach to high habitat-use areas located upstream from the project would be prolonged through the concurrent implementation of other projects. File No. 1079/-005-00 Decemher 19, 2008 Page 8-113 GEOENGINEEAS .i I I I I I I I I I I I I I I I I I I I ~ ~ .,; i ;; ~ > • oc ~ ~ "~, '. . C .·. ,, 0 ..... ~,--. ~~~~ ;71. ~-~-.~-_ _ -~~- •• '>...l.,' ~j ·,, ,1 -~~ ...... -'",;-o. ~'-) . ' 310 309 ' ' "'· C ~ <:, /: C , .. 1 -" ·1 ";, Conceptual Channel Profile: IFP 2 0 ,, . :.,',. ' ""' '-f'_ C ,·,..: .. ~~ "t ~- ' \". \"< ' ~,;," f·.·· ,._..,,..· -1··~- !'/··....:;._ __ ._:;:, .. ':-..... , :. ..... ~· q . ~ -. <« . ..i.., t 0 .,, a ' ·~ . ,, , C ..; ..... i._., ."v " . "a-:- ' ' '. ,."(• ,c,:r, Conceptual Cross Section: IFP 2 (RMS.167) 311.5 < -,:,,-.·~· . .,:,,0 ~ ~, • ,. ; ,/1'",Y', ·~ -,,-._, 1. • . ''/;/·,f··,, "I:) ,_~,. -: t1 wr1. .";~t'!. ~. ,1--J -:, ' }Li> "_O ,._. ···! _,,. ., ...,,._ ,. ·,:,,:,•·,_ ",1· '> ,/1;', '/ ,,; ' ' . " {{t,t:~{~;< '~ '•. '. ·:/.,'; ' ' . ~~--.: OU ,:~ , ' '·to '-.~ "·( "'-'t '·-r 1) ... ,'-. '~ ......... !" . ( :;..• -, ... ,, ' ' ='\; l,. ~-z.:!,·,:;,.. (-+(!-·· ... _.,:::.. f·r ,){'•;,a :~~-., , '>-'~ ', C .._ r;3<.. .' ~l ~ , \ .,. • ,. 'Lf''•/"•: u -·. T l ,-. ,• ,' ,·· C ,. • ~-. -·~.:, _,\. ,)". -• '-->-u ,, ,,.,),r .. _ ... \ +.:; .-.• · .. l' , ~-, '-· /:',,, •. ' -.,.. 1 .. ,} 1 Q/li~·~(' ,·o>'-1'{ .•. ;~ :tJ,r-,._;:,;_r-..,:.._'.fJ: · .. ,· 1' .,~,< 'V' ,.,, "'-, )"C't...-).f"""' "1_ ' J ,, •.,.,""\I) "··r'• ,\.:~', ,""'": ,:"""-"' ·.<-,;L,v 'I~ .i<,·ll'.<I(,..,.•,;-; ~ l \ "}_' ___ ll::'J_ i"f! __ rt:¢;,L-'!'.~~,: ' ' --,..(,·£• ·,. "') i;-. ~,<" Map Legend Project Length 311 310.5 310 308 307 ~ / ........ ~ y ""' / \ •••• -~·-·-·-· •-·---,---=·-·-·-·-··I Roads @: 309.5 > " 309 iii @: 306 C ,g 305 .. > -, ·--I ' I ·, I 308.5 308 307.5 · " g .S! 304 w 303 I ~ j I N g • ~ X ;; w ~ ~ 8 ~ ~ 0 6 ~ ~ 302 301 300 5 5.05 5.1 5.15 5.2 5.25 River Station (miles) -Existirg Grour-d 307 ·. 50 60 70 5.3 5.35 5.4 ---Existing Ground -Proposed Ground ---Proposed Ground ~, " ~ Reference: USGS EDC Ortho Urban aerial photos provided by the USGS Seamless data server. The May Creek stream layer and roads were provided by King County. Notes: • J 80 90 100 110 Feet • , Existing 2yr Water Surface , Proposed 2yr Water Surface " 1. The locations of all features shown are approximate. i 2. This drawing is for infomation purposes. It is intended to assist in showing features discussed in an attached document. GeoEngineers, Inc. can not guarantee the accuracy and content of electronic files. The master file is stored by GeoEnoineers, Inc. and will serve as the official record oth this communication. ~ ·----· ---~ ----·;:, 120 200 May Cr./ River Mile (RM) 0 ~~ 4-~ 200 ~ --< -' --·"' *' ~ ---Feet Conceptual Drawings Ineffective Flow Project 2 (IFP 2) May Creek, King County, Washington I GEOIENGINEER~ I Figure IFP 2 I I I I I I I I I I I I I I I I I I I Potential Challenges and Limitations The single greatest challenge and limitation to IFP 2 is the ephemeral nature of the solution proposed. While this project is expected to immediately address flood duration, conveyance, fish passage, and other issues, the benefits are expected to be short-lived. Improvements made to channel performance through the mechanical manipulation of channel cross-section and profile would be expected to degrade over time as each runoff event conveys new sediment into the May Valley. As the May Valley is naturally a sediment deposition zone, and as sediment sources in the headwaters of the May Valley remain unmitigated, May Creek would be expected to fill back in. Therefore, the implementation of IFP 2, absent any other action, would not be expected to serve a long-term solution to the flood duration, sedimentation, fish passage, or other issues in this section of May Creek. Unless this project is augmented by upstream and perhaps downstream solutions offered in Projects I through 29 and through implementation of stormwater and sediment control solutions in May Valley headwaters areas, the short- term flooding and fish passage benefits realized through implementation of lFP 2 will be lost. Another potential challenge to implementation of this project is the need to work with a large number of private landowners and land managers to fully implement project lFP 2. The project encompasses a reach of May Creek approximately 3,200 feet long. The project would need to be implemented throughout this length for expected benefits to be realized. Landowners must grant permission for these projects to be implemented. It is unknown if these actions would be of interest to the landowners. Another challenge to this project is the fact that a large amount of channel would be disturbed below the Ordinary High Water Mark (OHWM). The proposed removal of silty substrate and vegetation from within the channel would be expected to cause concern among regulatory agencies, including WDFW and the Tribes. Additional regulatory constraints may be imposed on the proposed project due to the fact that much of May Creek in the May Valley was historically a forested wetland (Conditions Report, King County 1995), and continues to maintain wetland and other critical habitat functions in its present, degraded condition. Wetland delineation would need to be completed to determine the extent of wetland features at the site. Any impacts to stream buffers, wetlands and wetland buffers would need to be mitigated if the project were permitted and implemented. Planning-Leve/ Cost Estimates Estimated Construction Costs: $58,220 (See Appendix C for details). Design, construction observation and permitting costs arc not included as these costs can vary significantly Permitting A substantial portion of the work would be completed below the OHWM and will require placing fill into a critical area, the following permits and approvals likely will be required: • U.S. Army Corps of Engineers (ACOE) Section 404 • Washington State Department of Fish and Wildlife (WDFW) Hydraulic Project Approval • Washington State Department of Ecology (Ecology) 401 Water Quality Certification • King County Clearing and Grading Permit o SEPA Checklist, with King County lead o King County Critical Areas Review • Compliance with the King County Shoreline Regulations • Tribal and WDFW area biologist consultation File No. /0791-005-00 December I 9. 2008 Page B-115 GeoENGINEEIIS.i This project would disturb we11 over l acre of area, necessitating additional permitting and regulatory considerations. Additional regulatory constraints may also be imposed on the proposed project due to the fact that much of May Creek in the May Va11ey was historica11y forested wetland (Conditions Report, King County 1995) or contains other critical areas. A wetland delineation and critical areas assessment would need to be completed to detennine the extent and function of wetland and other habitat features at the site. Any impacts to stream buffers, wetlands and wetland buffers would need to be mitigated if the project were pennitted and implemented. File No. 10791-005-00 December I 9, 2008 Page B-116 GEOENGINEER~ I I I I I I u I I I I I I I I I I I I I I I I I I I I I I I I PROJECT IFP-3: INEFFECTIVE FLOW PROJECT 3 • 291-A TO HENDRIX CREEK Project IFP 3 treats ineffective flow areas within the mainstem channel from 291A to Hendrix Creek using direct channel modifications of the stream cross-section and channel profile. The project uses mechanical methods to create a positive channel slope where the channel currently exhibits extremely flat and/or negative slopes (Figure IFP 3, see Conceptual Channel Profile insert). The purpose of the project is to increase water and sediment conveyance through the channel, thereby reducing the duration of flooding and improving fish passage. This project was identified as a Category E project during the prioritization process. Site Location Project number IFP 3 is located on the mainstem May Creek between RM 5.48 and RM 6.53 (Figure 15 and 16, Appendix A) between Tributary 291A and County/Cabbage Creek. The creek segment to be treated represents a distance of approximately 1.05 river miles (5,575 feet). This ineffective flow project runs adjacent to Projects 15, 16, 17, 18, 19, 20, 21, 22, 23 and 24 (Figure 15 and 16, Appendix A). Site Description This project area includes most of Reach 3, all of Reach 4, and the lowermost portion of Reach 5. The site traverses a wetland (see Figure 5, Appendix A) and is currently used as horse pasture and as wetland open space. It is reported in the Conditions Report (King County 1995) that historic land use in the area eliminated a previously existing conifer and deciduous-based forested wetland. A portion of the wetland is still present at the site (see Figure 5, Appendix A); however, the existing remnant wetland is dominated by reed canarygrass and willow with limited other wetland or riparian species. The section of May Creek flowing through the wetland has minimal flow and sediment conveyance capacity as the result of ongoing sediment deposition and encroachment of reed canary grass in the channel. Although this area no longer functions as a forested wetland, it does still provide some value in terms of flood attenuation, nutrient assimilation, and habitat value in its degraded condition (see Figure 8 and 9, Appendix A). In addition, the lower-most section of IFP 3, located adjacent projects 15 and 16 has previously been identified as a high fish habitat use area (Action Plan, King County 200 I). Recent preliminary hydraulic modeling completed by OTAK (2006) as part of this project revealed areas of ineffective flow in this reach of May Creek, suggesting that issues identified in the Action Plan can be expected to persist unless addressed. This ineffective flow area can be attributed to slow flow velocities ( average 1.4 ft/sec) and the accumulation of sediment within the channel upstream of bridge constrictions and crossings. Project Description This project would address ineffective flow and passage barrier issues in an approximately 5,575 foot section of May Creek. Ineffective flows would be addressed through the mechanical manipulation of the channel cross-section area and longitudinal profile (Figure IFP 3). Sediment and vegetation would be mechanically removed from the channel to create a more uniform longitudinal stream profile throughout the site, providing a relatively uniform channel bottom width, and reducing roughness in the channel by removing all encroaching vegetation. Based on measurements of reference reaches along May Creek where flows were found to be effective, the average channel bottom width was determined to be 15-feet with 1.5: I (horizontal:vertical) side slopes. This project would recreate a channel bottom width and side slopes to match the reference reach channel dimensions. As a result, implementation of IFP 3 would establish an overall positive channel File No. /0791-005-00 Decemher /9, 2008 Page 8-1/7 GeoENGINEERS..,@ slope of 0.0017. This would replace a channel longitudinal profile that currently exhibits flat and negative slopes for the majority of the segment length intermixed with short moderately steep sections. A typical proposed cross section is illustrated on Figure IFP-3 (see Conceptual Cross Section insert). Channel side slopes will be recreated at a 1.5: I (horizontal:vertical), up to the point of intersection with the existing floodplain. By constructing the channel side slopes in this manner the area of disturbance would be minimized, floodplain fill would be avoided, and the design would aid in vegetation retention. During the redefining of this channel most of the instream vegetation will be removed. It is also recommended that vegetation be removed approximately within 5 feet of both the left and right channel banks during construction of this project. Other projects proposed in the vicinity of project IFP 3 could support the need for riparian vegetation restoration. Projects 15, 19, 20, 21 and 22 include riparian enhancement along May Creek for most of the length of the IFP 3 site. Such projects may well provide for the need to remove vegetation from the 5 feet adjacent the stream bank in this section of the project, if IFP 3 is implemented. Some form of vegetated buffer will be necessary to delay any necessary routine maintenance to control vegetation within the channel for the first few years. Project Efficacy If IFP 3 were implemented, the channel profile would be more uniform to promote better downstream conveyance of both water and sediment. The removal of in-channel vegetation would also benefit the project by reducing choking and blocking of the channel, while also improving fish passage conditions. The proposed project would increase overall channel velocity, and in-channel conveyance and would reduce frequent bank overtopping and broad shallow flooding during high recurrence events. The project may also reduce water temperatures, improve sediment conveyance, and provide more suitable stream habitat for fish and wildlife. Recent preliminary hydraulic modeling completed by OTAK (2006) as part of this project revealed that this segment of May Creek contains some minor ineffective flow areas. The modeling indicated that ineffective flow in this reach of May Creek is also slightly increased due to proposed projects downstream (IFP I and IFP 2). Based on the distance between the three sites, the physical characteristics of the sites, and comparison of modeling results upstream and downstream, it is expected that the increase in ineffective flow in IFP 3 is negligible. The ineffective flow area associated with IFP 3 can be attributed to frequent shallow flooding and the accumulation of sediment within the channel upstream of a bridge constriction and crossing as well as at the mouths of tributaries. GeoEngineers used HEC-RAS hydraulic models developed by OTAK (OTAK 2006) to evaluate the efficacy of IFP 3. The evaluation was based on a conceptual project design as described in the project description section above. Based on modeling results this project would be expected to help mitigate the ineffective flow area in this segment. As described in the main body of the Conceptual Restoration Plan, IFP 3 would improve the ineffective flow ranking from an overall ranking of 2.8 (average ineffective flow) down to a ranking of 1.9 (minor ineffective flow), if done simultaneously with IFP I and IFP 2. It should be noted, however, that this improved ranking assumes that IFP I and IFP 2 are implemented at the same time. This mitigation project would also help alleviate the flooding of May Creek in the direct vicinity of the project. During the 2-year flows the in-channel conveyance would increase from 66 to 91 percent which means that less water would escape the channel. Another hydraulic benefit of this project is that it would maintain existing flow velocities in the range of 2.8 ft/sec to 2.6 ft/sec which would help more sediment through the reach and reduce the ability of vegetation to re-grow within the channel. File No, 1079 J-{}05-00 December I 9, 2008 Page B-118 GtOENGINEfRS_t;I I I I I I D I I I I I I I I I I I I I I I I I I I I I I I I I 0 g I '" • ll' ~ 6 X ~ I w § @ 0 0 ;; ' I 0 6 ~ s ~ I I Conceptual Channel Profile: IFP 3 319 317 ~~- 315 g 6 313 ., .. > .5! 311 UJ 309 307 305 5.3 5.4 5.5 5.6 5.7 5.8 5.9 6 6.1 6.2 6.3 6.4 6.5 6.6 6.7 River Station (miles) Conceptual Cross Section: IFP 3 (RM 5.862) 319 ,--------------- -::: j .... : ........... ---~ ..... -~ -1-1' .......... -~ ;!;. 1 ' ' -!1"-~ ~ ili 315 I _ • iii 314 i \- 3131 \ ~----.~-----------l -------'"----J------~--1 312 311 25 35 ~ Existing Ground I ---Proposed Ground 45 55 65 75 85 95 Feet ---. Existing 2yr Water Surface ---. Proposed 2yr Water Surface Map Legend Project Length Roads May Cr. / River Mile (RM) ~•~ ·s 200 0 200 f --- _,. __ _ Feet I Conceptual Drawings [ -Existing Ground -Proposed Ground 11 Ineffective Flow Project 3 (IFP 3) : ---------------------~ Reference: USGS EDC Ortho Urban aerial photos provided by the USGS Seamless data server. The May Creek stream layer and roads were provided by King County. Notes: 1. The locations of all features shown are approximate. 2. This drawing is for infomation purposes. It is intended to assist in showing features discussed in an attached document. GeoEngineers, Inc. can not guarantee the accuracy and content of electronic files. The master file is stored by GeoEngineers, Inc. and will serve as the official record oth this communication. May Creek, King County, Washington I GEoENGINEER~ I Figure IFP 3 I I I I I I I I I I I I • I I I I I Potential Challenges and Limitations The single greatest challenge and limitation to IFP 3 is the ephemeral nature of the solution proposed. While IFP 3 would be expected to immediately address flood duration, conveyance, fish passage, and other issues, the benefits would be expected to be short-lived. Improvements made to channel performance through the mechanical manipulation of channel cross-section and profile would be expected to degrade over time as each runoff event conveys new sediment into the May Valley. As the May Valley is naturally a sediment deposition zone, and as sediment sources in the headwaters of the May Valley remain unmitigated, May Creek would be expected to fill back in. Therefore, the implementation of IFP 3, absent any other action, would not be expected to serve a Iong-tenn solution to the flood duration, sedimentation, fish passage, or other issues in this section of May Creek. To have value, implementation of IFP-3 must be supplemented with other projects described in this Conceptual Restoration. Plan. The flood and habitat-related benefits of IFP 3 are expected to be short-lived and must, therefore, be augmented with longer-term solutions such as those described in Projects 1 through 29. Another potential challenge to implementation of this project is the need to work with a large number of private landowners and land managers to fully implement project IFP 3. The project encompasses a reach of May Creek approximately 5,575 feet long. The project would need to be implemented throughout this length.for expected benefits to be realized. Landowners must grant permission for these projects to be implemented. It is unknown if these actions would be of interest to the landowners. Another challenge to this project is the fact that a large amount of channel would be disturbed below the Ordinary High Water Mark (OHWM). The proposed removal of silty substrate and vegetation from within the channel would be expected to cause concern among regulatory agencies, including WDFW and the Tribes. Additional regulatory constraints may be imposed on the proposed project due to the fact that much of May Creek in the May Valley was historically a forested wetland (Conditions Report, King County 1995), and continues to maintain wetland and other critical habitat functions in its present, degraded condition. Wetland delineation would need to be completed to determine the extent of wetland features at the site. Any impacts to stream buffers, wetlands and wetland buffers would need to be mitigated if the project were permitted and implemented. Planning-Level Cost Estimates Estimated Construction Costs: $356,900 (See Appendix C for details). Design, construction observation and permitting costs are not included as these costs can vary significantly Permitting A substantial portion of the work would be completed below the OHWM and would be expected to result in fill being placed in a critical area. Therefore, the following permits and approvals would likely be required: • U.S. Army Corps of Engineers (ACOE) Section 404 o Washington State Department of Fish and Wildlife (WDFW) Hydraulic Project Approval o Washington State Department of Ecology (Ecology) 401 Water Quality Certification • King County Clearing and Grading Permit • SEP A Checklist, with King County lead • King County Critical Areas Review • Compliance with the King County Shoreline Regulations • Tribal and WDFW area biologist consultation Fife No. 1079/-005-00 December /9, 2008 PageB-IW I I I I I I I I I I • I I I I I I I This project would disturb over I acre of ground. As a result, additional pennit would be required, including ACOE Section 404 project-specific permitting and requirements under Ecology's National Pollutant Discharge Elimination System (NPDES), securing a Construction Stormwater General Permit. File No. 1079/-005-00 Decemher 19, 2008 Page B-111 GEOENGINEEIIS.i PROJECT IFP4: INEFFECTIVE FLOW PROJECT 4-NORTH FORK MAY CREEK Project IFP 4 treats ineffective flow areas within the North Fork May Creek using direct channel modifications of the stream cross-section and channel profile. The project uses mechanical methods to create a positive channel slope where the channel currently exhibits flat and/or negative slopes (Figure IFP 4, see Conceptual Channel Profile insert). The purpose of the project is to increase water and sediment conveyance through the channel, thereby reducing the duration of flooding and improving fish passage. This project was identified as a Category E project during the prioritization process. Site Location Project IFP 4 is located on the mainstem May Creek and the North Fork May Creek between RM 6.95 and RM 7.30 (Figure 18, Appendix A). The project area begins approximately 250 feet downstream of the Renton-Issaquah (SR 900) bridge crossing May Creek and extends upstream into the North Fork May Creek approximately I ,600 feet, for a total length of approximately 1,850 feet. This ineffective flow project runs adjacent to Project 29 (Figure 18, Appendix A). Site Description This project is located in the uppermost portion of Reach 5 and the lowermost portion of Reach 6 encompassing the North Fork May Creek. The site traverses a wetland (see Figure 5, Appendix A) and is currently maintained as open space, including a Washington State Department of Transportation environmental protection area. It is reported in the Conditions Report (King County 1995) that historic landuse in the area degraded a previously existing conifer and deciduous-based forested wetland. A portion of the wetland is still present at the site (see Figure 5, Appendix A); however, the existing remnant wetland is dominated by reed canarygrass and willow with limited other wetland or riparian species., with a small portion of forested wetland remaining on the north side of May Creek downstream from the SR-900 bridge crossing. The upper-most section of IFP 4, located upstream from Project 29 has previously been identified as a high fish habitat use area (Action Plan, King County 200 I). See Figure 5 (Appendix A) for the location of the high fish habitat use area. The section of May Creek flowing through the wetland has minimal flow and sediment conveyance capacity as the result of ongoing sediment deposition and encroachment of reed canarygrass in the channel. Although this area no longer functions as a forested wetland, it does still provide some value in terms of flood attenuation, nutrient assimilation, and habitat value in its degraded condition (Figure I I, Appendix A). Recent preliminary hydraulic modeling completed by OTAK (2006) as part of this project revealed areas of ineffective flow in this reach of May Creek, suggesting that issues identified in the Action Plan can be expected to persist unless addressed. This ineffective flow area can be attributed to slow flow velocities (average 1.4 ft/sec) and the accumulation of sediment within the channel upstream of bridge constrictions and crossings. Project Description This project would address ineffective flow and passage barrier issues in an approximately 1,850 foot section of May Creek. Ineffective flows would be addressed through the mechanical manipulation of the channel cross-section area and longitudinal profile (Figure IFP 4). Sediment and vegetation would be mechanically removed from the channel to create a more unifonn longitudinal stream profile throughout the site, providing a relatively uniform channel bottom width, and reducing roughness in the channel by removing all encroaching vegetation. File No. 10791-005-00 December I 9, 2008 Page B-122 GEOENGINEEIIS_B I I I I I I I I . I I I I I I I I I I I I I • I I I I I Based on measurements of reference reaches along May Creek where flows were found to be effective, the average channel bottom width was determined to be 15-feet with 1.5:1 (horizontal:vcrtical) side slopes. This project would recreate a channel bottom width and side slopes to match the reference reach channel dimensions. As a result, implementation of IFP 4 would establish an overall positive channel slope of 0.0047. This would replace a channel longitudinal profile that currently exhibits flat and negative slopes over the majority of the segment length intermixed with short steep sections. A typical proposed cross section is illustrated on Figure IFP-4 (see Conceptual Cross Section insert). Channel side slopes will be recreated at a 1.5: I (horizontal:vertical), up to the point of intersection with the existing floodplain. By constmcting the channel side slopes in this manner the area disturbance would be minimized, floodplain fill would be avoided, and the design would aid in vegetation retention. During the redefining of this channel most of the instream vegetation will be removed. It is also recommended that vegetation be removed approximately within 5 feet of both the left and right channel banks during constmction of this project. Project Efficacy If IFP 4 were implemented, the channel profile would be more uniform to promote better downstream conveyance of both water and sediment. The removal of in-channel vegetation would also benefit the project by reducing choking and blocking of the channel, while also improving fish passage conditions. The proposed project would increase overall channel velocity, in-channel conveyance and reduce frequent bank overtopping and broad shallow flooding during high recurrence events. The project may also reduce water temperatures, improve sediment conveyance, and provide more suitable stream habitat for fish and wildlife. GeoEngineers· used HEC-RAS hydraulic models developed by OTAK (OTAK 2006) to evaluate the efficacy of IFP 4. The evaluation was based on a conceptual project design as described in the project description section, above. Based on modeling results this project would be expected to help mitigate the ineffective flow area in this area of the May Valley. As described in the main body of the Conceptual Restoration Plan, IFP 4 would improve the ineffective flow ranking from an overall ranking of 3.1 (moderate ineffective flow) down to a ranking of0.8 (no ineffective flow). This mitigation project would also help alleviate the flooding of May Creek in the direct vicinity of the project. During the 2-year flows the in-channel conveyance would increase from 59 to 99 percent which means that less water would overtop the channel banks: With the increase in a more uniform channel slope and an actual defined channel flow velocities would increase from 2.7 ft/sec to 3.9 ft/sec which would help convey more sediment through the segment and could create some scour and deposition holes to increase habitat diversity. The increase in velocity would also help reduce the ability of vegetation to re-grow within the channel. Potential Challenges and Limitations The single greatest challenge and limitation to IFP 4 is the ephemeral nature of the solution proposed. While IFP 4 would be expected to immediately address flood duration, conveyance, fish passage, and other issues, the benefits would be expected to be shmt-lived. Improvements made to channel performance through the mechanical manipulation of channel cross-section and profile would be expected to degrade over time as each runoff event conveys new sediment into the May Valley. As the May Valley is naturally a sediment deposition zone, and as sediment sources in the headwaters of the May Valley remain unmitigated, May Creek would be expected to fill back in. Therefore, the implementation of IFP 4, absent any other action, would not be expected to serve as a long-term solution to the flood duration, sedimentation, fish passage, or other issues in this section of May Creek. To have value, implementation of IFP-4 must be supplemented with other projects described in this Conceptual Restoration Plan. The flood and habitat-related benefits of IFP 4 are expected to be short-lived and must, therefore, be augmented with longer-term solutions such as those described in Projects I through 29. File No. /079/-005-00 December 19, 2008 Page B-123 GEOENGINEEIIS_B I I I I I I I I I I I I I I I I I I I .~ -~ .-.~c,r, ' ,,. ,· ,. "\ . ' ' , ·" (~ ~ 0 0 N ""L----,- i ' ,! . ''{/~ j . ,, -:.,.~--~ I "' . -~ ... -~ ·;.;_;;: ;~. ,, 0::: ,:,. • .J!r.l') ~,,. ~ ~ (~ \. -~-- ., "'7 ·~· ~ ~..:...'. o \..\ , ..... ,. r .......... . ,.,,;.,-"'·-.Mr .. v;r.: ';'""" . ,....f «I .--~':J ...• -:-,-,,, , t:: -... ; "!;,.Ir ,. --,--i6. -:.,. ·-1,:· ~ .. , -~ ""I;.""'-~..-. ''l'·""fj-:--, , • ~ -< ··:W!ffl'f'"' -__ L.L__. . • 1-·-· · .. d · " '::1 --; '.'::)•I · f-J"' "' ---· ·< ·~ F ,e~ • ·, · • • C --'> '· · ,_ t 340 Conceptual Channel Profile: IFP 4 I Conceptual Cross Section: IFP 4 (RM 7.071) 336 ·---------------------------~ ~ g ~ 1l, ~ iS X ~ ~ I ~ 6 ~ ~ 338 336 334 !!:. 332 C: ,ll 330 .. > -9! 328 w 326 324 322 320 6.8 ---___.......... / ~ /~ f'7 -----V 6.85 6.9 6.95 7 7.05 7.1 7.15 7.2 7.25 7.3 River Station (miles) -Existing Ground -Proposed Ground 334 --332 g ii; 330 iii 328 · 326 324L....------~---~---~-----------~ 370 380 390 400 410 420 430 440 Feet 7.35 7.4 --Existing Ground . Existing 2yr Water Surface --Proposed Ground . Proposed 2yr Water Surface ----. ~ I Reference: USGS EDC Ortho Urban aerial photos provided by the USGS Seamless data server. The May Creek stream layer and roads were provided by King County. -. --~: ~ Map Legend Project Length Roads % ..... ,.~ ' Ir" n May Cr. / River Mile (RM) /y:d.. '(fS:I~ J' ~ ' L'. 200 0 200 -'~•~ ·-'" -~-~---.,. Feet Conceptual Drawings Ineffective Flow Project 4 (IFP 4) May Creek, King County, Washington Notes: I a I I 1. The locations of all features shown are approximate. G IC s_fj) · } ~· This drawing is fo~ infomation purpo~es. It is intende~ to assist in sho~ing featurr:s d!scussed in an attached document. GeoEngineers, lnc. can not guarantee the accuracy and content of electronic files. The master file EO I[: NGIN EE RS Figure IFP 4 lL:1S~s=t=o~red:::_:b~y~G=e=o=E=n2g~,n~e=•=r=s~,~ln~c~.=•=n=d~w=1~ll=s=e~rv=e~a=s::..:th:e~o=ff~1:c:ia~l~re:co::::::r:d~o=t=h~t~h1:s~c=o~m~m=u=n=1ca:::_:t':o=n~.--------------------------------------------------------~·====================·=======~·J I I I I I I I I I I I I I I I I I I Another potential challenge to implementation of this project is the need to work with a number of private landowners and land managers to fully implement project IFP 4. The project encompasses a reach of May Creek approximately 1,850 feet long. The project would need to be implemented throughout this length for expected benefits to be realized. Landowners must grant permission for these projects to be implemented. It is unknown if these actions would be of interest to the landowners. Another challenge to this project is the fact that a large amount of channel would be disturbed below the Ordinary High Water Mark (OHWM). The proposed removal of silty substrate and vegetation from within the channel would be expected to cause concern among regulatory agencies, including WDFW and the Tribes. Additional regulatory constraints may be imposed on the proposed project due to the fact that much of May Creek in the May Valley was historically a forested wetland (Conditions Report, King County 1995), and continues to maintain wetland and other critical habitat functions in its present, degraded condition. Wetland delineation would need to be completed to determine the extent of wetland features at the site. Any impacts to stream buffers, wetlands and wetland buffers would need to be mitigated if the project were permitted and implemented. Planning-Level Cost Estimates Estimated Construction Costs: $186,900 (See Appendix C for details). Design, construction observation and permitting costs are not included as these costs can vary significantly. Permitting A portion of the work will be completed below the OHWM and will require placing fill into a critical area, the following pennits and approvals likely will be required: • U.S. Army Corps of Engineers (ACOE) Section 404 • Washington State Department of Fish and Wildlife (WDFW) Hydraulic Project Approval • Washington State Department of Ecology (Ecology) 401 Water Quality Certification • King County Clearing and Grading Permit • SEPA Checklist, with King County lead • King County Critical Areas Review • Compliance with the King County Shoreline Regulations • Tribal and WDFW area biologist consultation This project would disturb over I acre of ground. As a result, additional permit would be required, including ACOE Section 404 project-specific pennitting and requirements under Ecology's National Pollutant Discharge Elimination System (NPDES), securing a Construction Stormwater General Permit. File No. 10791-005-00 December 19, 200R Page 8-125 GEOENGIN£ERS_g GEOENGINEER~ APPENDIXC PLANNING-LEVEL COST ESTIMATES '1 I I 'I I ' I I , :I I I I I I I I I I I I I I I I I I I I I I I I MAY CREEK PLANNING LEVEL -COST ESTIMATE LAST UPDATE: 06/04/2008 MATERIAL DESCRIPTION CLEARING+ GRUBBING+ AND ROADSIDE CLEANUP ClearinQ and Grubbinn REMOVAL OF STRUCTURES AND OBSTRUCTIONS Remove Pavement Sawcut Asnhalt Concrete GRADING AND EXCAVA T/ON Structure Excavation tExcavation Underneath Structures) Channel Excavation Fine Gradina MINERAL AGGREGATES Crushed Surface Base Course Boulders PAVEMENT t.sohalt Concrete Pavement Patchina DRAINAGE SYSTEMS Rein. Cone. Box Culvert 1 O' Soan x 4' Rise EROSION CONTROL Hvdro-Seedina Mattina, Jute MattinQ, Wood Excelsior Fence, Temoorarv Silt Containment Hiah Visibilitv Fence LANDSCAPING Wet Pond Seedina MISC ITEMS Plantino Preoaration Reveaetation (Cadillac Scenario One\ Revenetation (Cheanest Scenario Three) Reveaetation (Tree and Shrub Suoclementation in Rinarian Corridor) Bioenc ineerina Bank Stabilization Beaver Deceiver Bioswale Construction /Includes Excavation Gradina and Seedina) OTHER ITEMS Temnorarv B"nass Erosion and Sedimentation Contro1··15%\ Traffic Control on Minor Roads (7%, raffic Control on Maior Roads (10% \ Land Acauisition Larae Woodv Debris (QntionaP SUBTOTAL CONSTRUCTION COST Sa/es Tax (8.9% TOTAL CONSTRUCT/ON COST UNIT AC SY LF CY CY CY TN TN TN LF SF SF SF LF LF SF AC AC AC AC LF EA SF LS LS LS LS $ EA P:\ 1O\10791005\00\Finals\December 2008 Final Draft\Appendix C\Appendix C.xls $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ TOTAL UNIT PRICE QUANTITY 8,000.00 14.05 22.00 420 3.50 300 30.00 1678 18.00 28668 25.00 2940 28.00 3980 60.00 305 106.00 150 1,200.00 180 1.00 146900 1.50 1000 1.00 20000 6.00 14275 2.00 14275 3.00 5100 5,000.00 17.28 35,000.00 14.73 10,000.00 6.05 3,500.00 21.42 110.00 1894 2,500.00 1 10.00 34025 75,000.00 6 5% 33 7% 6 10% 8 1.00 415000 1,000.00 45 PROJECT 6 QUANTITY 0.7 $ $ $ $ 525 $ $ $ $ $ $ $ $ $ $ $ $ 0.7 $ 0.7 $ $ 2.6 $ $ $ $ $ 1 $ $ $ $ $ ~ $ $ $ AMOUNT 5,600.00 - - - 9,450.00 - - - - - - - - - - - 3,500.00 24,500.00 - 9,100.00 - - - - 2,745.00 - - - - 54,900.00 4,900.00 59,800.00 PROJECT 7 QUANTITY AMOUNT 1.2 $ 9,600.00 70 $ 1,540.00 50 $ 175.00 100 $ 3,000.00 1300 $ 23,400.00 $ - 30 $ 840.00 $ - 25 $ 2,650.00 30 $ 36,000.00 22000 $ 22,000.00 $ - 5000 $ 5,000.00 2200 $ 13,200.00 2200 $ 4,400.00 $ - $ - $ - $ - $ - $ - $ - $ - 1 $ 75,000.00 1 $ 11,180.00 1 $ 15,652.00 $ - $ - $ - $ 223,600.00 $ ~900.00 $ 243,500.00 PROJECT 8 QUANTITY AMOUNT 0.25 $ 2,000.00 $ - $ - $ - 120 $ 2,160.00 $ - $ - $ - $ - $ - $ - $ - $ - $ - $ - $ - 1.5 $ 7,500.00 1.5 $ 52,500.00 $ - 1.5 $ 5,250.00 $ - $ - $ - $ - 1 $ 6,810.00 $ - $ - 60000 $ 60,000.00 $ - $ 136,200.00 $ 12,100.00 $ 148,300.00 PROJECTS QUANTITY 0.6 $ $ $ $ $ 560 $ $ $ $ $ 11000 $ $ 2000 $ 1000 $ 1000 $ 1400 $ 0.3 $ 0.1 $ 0.2 $ $ $ $ $ $ 1 $ 10000 $ $ $ $ $ $ $ AMOUNT 4,800.00 - - - - 14,000.00 - - - - 11,000.00 - 2,000.00 6,000.00 2,000.00 4,200.00 1,500.00 3,500.00 2,000.00 - - - - - 3,210.00 - - 10,000.00 - 64,200.00 5,700.00 69,900.00 PROJECT10 QUANTITY AMOUNT 0.25 $ 2,000.00 $ - $ - $ - 150 $ 2,700.00 $ - $ - $ - $ - . $" - $ - $ - $ - $ - $ - $ - 0.2 $ 1,000.00 0.2 $ 7,000.00 $ - 1 $ 3,500.00 $ - $ - $ - $ - 1 $ 4,800.00 $ - $ - 75000 $ 75,000.00 $ - $ 96,000.00 $ 8,500.00 $ 104,500.00 I I I I I I I I I I I I I I I I I I I MAY CREEK PLANNING LEVEL -COST ESTIMATE LAST UPDATE: 06/04/2008 MATERIAL DESCRIPTION CLEARING+ GRUBBING+ AND ROADSIDE CLEANUP Clearina and Grubbina REMOVAL OF STRUCTURES AND OBSTRUCTIONS Remove Pavement Sawcut Asohalt Concrete GRADING AND EXCAVATION Structure Excavation (Excavation Underneath Structures) Channel Excavation Fine Gradinq MINERAL AGGREGATES Crushed Surface Base Course Boulders PAVEMENT Asphalt Concrete Pavement Patchinn DRAINAGE SYSTEMS Rein. Cone. Box Culvert 10' Snan x 4' Rise EROSION CONTROL Hvdro-Seedina Mattinq, Jute Mattina, Wood Excelsior Fence, Temoorarv Silt Containment Hiah Visibilitv Fence LANDSCAPING Wet Pond Seedina MISC ITEMS Plantina Preoaration Reveqetation (Cadillac Scenario One' Reveaetation lCheaoest Scenario Three) Reveaetation (Tree and Shrub Suoolementation in Rioarian Corridor' Bioenaineerina Bank Stabilization Beaver Deceiver Bioswate Construction (Includes Excavation Gradina and Seedin-\ OTHER ITEMS emoorarv B"nass Erosion and Sedimentation Control (5%) I lraffic Control on Minor Roads (7%' Traffic Control on Maior Roads (10%) Land Ar-nuisition Lan::ie Woodv Debris (Ontional\ SUBTOTAL CONSTRUCTION COST Sales Tax (8.9%) TOTAL CONSTRUCT/ON COST UNIT AC SY LF CY CY CY TN TN TN LF SF SF SF LF LF SF AC AC AC AC LF EA SF LS LS LS LS $ EA P:\ 1O\10791005\00\Finals\December 2008 Final Draft\Appendix C\Appendix C.xls TOTAL UNIT PRICE QUANTITY $ 8,000.00 14.05 $ 22.00 420 $ 3.50 300 $ 30.00 1678 $ 18.00 28668 $ 25.00 2940 $ 28.00 3980 $ 60.00 305 $ 106.00 150 $ 1,200.00 180 $ 1.00 146900 $ 1.50 1000 $ 1.00 20000 $ 6.00 14275 $ 2.00 14275 $ 3.00 5100 $ 5,000.00 17.28 $ 35,000.00 14.73 $ 10,000.00 6.05 $ 3,500.00 21.42 $ 110.00 1894 $ 2,500.00 1 $ 10.00 34025 $ 75,000.00 6 5% 33 7% 6 10% 8 $ 1.00 415000 $ 1,000.00 45 PROJECT 1 QUANTITY AMOUNT 0.5 $ 4,000.00 $ . $ . $ . 360 $ 6,480.00 $ . $ . 185 $ 11,100.00 $ . $ . 6000 $ 6,000.00 1000 $ 1,500.00 $ . 600 $ 3,600.00 600 $ 1,200.00 $ . $ . $ . $ . $ . 1200 $ 132,000.00 $ . $ . $ . 1 $ 8,730.00 $ . $ . $ . $ . $ 174,600.00 $ 15,500.00 $ 190,100.00 PROJECT2 QUANTITY AMOUNT 0.1 $ 800.00 70 $ 1,540.00 50 $ 175.00 100 $ 3,000.00 $ . $ . 30 $ 840.00 $ . 25 $ 2,650.00 30 $ 36,000.00 $ . $ . $ . $ . $ . $ . $ . $ . $ . $ . $ . $ . $ . 1 $ 75,000.00 1 $ 6,820.00 1 $ 9,548.00 $ . $ . $ . $ 136,400.00 $ --11., 100.00 $ 148,500.00 PROJECT 3 QUANTITY AMOUNT 0.5 $ 4,000.00 $ . $ . $ . 410 $ 7,380.00 $ . $ . 50 $ 3,000.00 $ . $ . 7000 $ 7,000.00 $ . 1000 $ 1,000.00 700 $ 4,200.00 700 $ 1,400.00 $ . 0.4 $ 2,000.00 $ . 0.4 $ 4,000.00 $ . 483 $ 53,130.00 $ . $ . $ . 1 $ 6,690.00 $ . $ . 40000 $ 40,000.00 $ . $ 133,800.00 $ __!!,_900.00 $ 145,700.00 PROJECT4 QUANTITY 0.5 $ $ $ $ 570 $ $ $ $ $ $ 9600 $ $ 1500 $ 1000 $ 1000 $ $ 0.3 $ $ 0.3 $ $ $ $ $ $ 1 $ $ $ $ $ . $ $ $ AMOUNT 4,000.00 . . . 10,260.00 . . . . . 9,600.00 . 1,500.00 6,000.00 2,000.00 . 1,500.00 . 3,000.00 . . . . . 1,995.00 . . . . 39,900.00 3,600.00 43,500.00 PROJECT 5 QUANTITY 0.6 $ $ $ $ 470 $ $ $ $ $ $ $ $ $ $ $ $ 1 $ 1 $ $ 2 $ $ $ $ $ 1 $ $ $ $ $ . $ $_ $ AMOUNT 4,800.00 . . . 8,460.00 . . . . . . . . . . . 5,000.00 35,000.00 . 7,000.00 . . . . 3,170.00 . . . . 63,400.00 5,600.00 69,000.00 I I I I I I I I I I I I I I I I I I I MAY CREEK PLANNING LEVEL -COST ESTIMATE LAST UPDATE: 06/04/2008 MATERIAL DESCRIPTION CLEARING+ GRUBBING+ AND ROADSIDE CLEANUP Clearinq and Grubbinn REMOVAL OF STRUCTURES ANO OBSTRUCTIONS Remove Pavement Sawcut Asnhalt Concrete GRADING AND EXCAVATION Structure Excavation {Excavation Underneath Structures) Channel Excavation Fine Gradino MINERAL AGGREGATES Crushed Surface Base Course Boulders PAVEMENT a.c:.nhalt Concrete Pavement Patchina DRAINAGE SYSTEMS Rein. Cone. Box Culvert 10' Soan x 4' Rise EROSION CONTROL Hvdro-Seedina Mattina, Jute MattinQ, Wood Excelsior Fence, Temoorarv Silt Containment Hiah Visibilitv Fence LANDSCAPING roet Pond Seedina MISC ITEMS Plantina Preoaration Reveaetation (Cadillac Scenario One\ Revenetation (Cheanest Scenario Three) Reveaetation <Tree and Shrub Suoclementation in Rinarian Corridor) Bioenc ineerina Bank Stabilization Beaver Deceiver Bioswale Construction /Includes Excavation Gradina and Seedino) OTHER ITEMS emnnrarv 9 .. nass Erosion and Sedimentation Control T5%' Traffic Control on Minor Roads f7% \ Traffic Control on Maier Roads (10%\ Land Arnuisition Larae Woodv Debris (Ootional\ SUBTOTAL CONSTRUCTION COST Sales Tax /8. 9% TOTAL CONSTRUCT/ON COST UNIT AC SY LF CY CY CY TN TN TN LF SF SF SF LF LF SF AC AC AC AC LF EA SF LS LS LS LS $ EA P:\10\10791005\00\Finals\December 2008 Final Draft\Appendix C\Appendix C.xls $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ TOTAL UNIT PRICE QUANTITY 8,000.00 14.05 22.00 420 3.50 300 30.00 1678 18.00 28668 25.00 2940 28.00 3980 60.00 305 106.00 150 1,200.00 180 1.00 146900 1.50 1000 1.00 20000 6.00 14275 2.00 14275 3.00 5100 5,000.00 17.28 35,000.00 14.73 10,000.00 6.05 3,500.00 21.42 110.00 1894 2,500.00 1 10.00 34025 75,000.00 6 5% 33 7% 6 10% 8 1.00 415000 1,000.00 45 PROJECT 11 QUANTITY 0.1 $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ 1.8 $ 1,8 $ $ $ $ $ $ $ 1 $ 5000 $ $ $ $ $ $ $ AMOUNT 800.00 . - . . . - - . . - . - - . . 9,000.00 63,000.00 - . . . . . 4,095.00 - - 5,000.00 . 81,900.00 7,300.00 89,200.00 PROJECT 12 QUANTITY 0.1 $ $ $ $ $ 225 $ $ $ $ $ 1400 $ $ 200 $ 150 $ 150 $ 1600 $ 0.2 $ 0.1 $ 0.1 $ $ $ $ $ $ 1 $ 10000 $ $ $ $ $ i $ AMOUNT 800.00 . . - - 5,625.00 . . . . 1,400.00 - 200.00 900.00 300.00 4,800.00 1,000.00 3,500.00 1,000.00 . . . . - 1,555.00 - . 10,000.00 . 31,100.00 2,800.00 33,900.00 PROJECT 13 QUANTITY 0.1 $ $ $ $ 65 $ $ $ $ $ $ $ $ $ $ $ $ 0.1 $ 0.1 $ $ 0.7 $ $ $ $ $ 1 $ 5000 $ $ $ $ -$ $ $ AMOUNT 800.00 . . . 1,170.00 - - - . . . . - - . - 500.00 3,500.00 - 2,450.00 . . - - 705.00 - - 5,000.00 - 14,100.00 1,300.00 15,400.00 PROJECT14 QUANTITY AMOUNT 0.2 $ 1,600.00 $ . $ . $ . 800 $ 14,400.00 $ . $ . $ . $ . $ . $ . $ . $ . $ . $ . $ . 0.6 $ 3,000.00 $ . 0.6 $ 6,000.00 $ . $ . $ . 11800 $ 118,000.00 $ . 1 $ 7,790.00 $ . $ . 5000 $ 5,000.00 $ . $ 155,800.00 $ 13,900.00 $ 169,700.00 PROJECT 15 QUANTITY 1 $ $ $ $ 485 $ $ $ $ $ $ 13000 $ $ 2000 $ 1400 $ 1400 $ $ 0.75 $ $ 0.75 $ $ $ $ $ $ 1 $ 20000 $ $ $ $ $ $ $ AMOUNT 8,000.00 . . . 8,730.00 . . . - . 13,000.00 . 2,000.00 8,400.00 2,800.00 . 3,750.00 - 7,500.00 . . . . . 3,905.00 - . 20,000.00 . 78,100.00 7,000.00 85,100.00 I I I I I I I I I I I I I I I I I I I MAY CREEK PLANNING LEVEL • COST ESTIMATE LAST UPDATE: 06/04/2008 MATERIAL DESCRIPTION CLEARING+ GRUBBING+ AND ROADSIDE CLEANUP Clearina and Grubbina REMOVAL OF STRUCTURES AND OBSTRUCTIONS Remove Pavement Sawcut Asphalt Concrete GRADING AND EXCAVATION Structure Excavation (Excavation Underneath Structures\ Channel Excavation Fine Gradina MINERAL AGGREGATES Crushed Surface Base Course Boulders PAVEMENT sohalt Concrete Pavement Patchina DRAINAGE SYSTEMS Rein. Cone. Box Culvert 1 O' Soan x 4' Rise EROSION CONTROL Hvdro-Seedino Mattina, Jute Mattina, Wood Excelsior Fence, Temnorarv Silt Containment Hiah Visibilitv Fence LANDSCAPING I/Vet Pond Seedina MISC ITEMS Plantina Preoaration Reveaetation Cadillac Scenario One) Reveaetation Cheanest Scenario Three\ Reveaetation Tree and Shrub Su .... lementation in Rioarian Corridor\ Bioenaineerina Bank Stabilization Beaver Deceiver Bioswate Construction (Includes Excavation Gradina and Seedin,.., OTHER ITEMS T emaorarv B"nass Erosion and Sedimentation Control (5%) raffic Control on Minor Roads (7%' Traffic Control on Maior Roads (10%) Land Al"nuisition Larae Woodv Debris (Ootionan SUBTOTAL CONSTRUCTION COST Sales Tax (8.9%) TOTAL CONSTRUCT/ON COST UNIT AC SY LF CY CY CY TN TN TN LF SF SF SF LF LF SF AC AC AC AC LF EA SF LS LS LS LS $ EA P:\10\10791005\00\Finats\December 2008 Final Draft\Appendix C\Appendix C.xls TOTAL UNIT PRICE QUANTITY $ 8,000.00 14.05 $ 22.00 420 $ 3.50 300 $ 30.00 1678 $ 18.00 28668 $ 25.00 2940 $ 28.00 3980 $ 60.00 305 $ 106.00 150 $ 1,200.00 180 $ 1.00 146900 $ 1.50 1000 $ 1.00 20000 $ 6.00 14275 $ 2.00 14275 $ 3.00 5100 $ 5,000.00 17.28 $ 35,000.00 14.73 $ 10,000.00 6.05 $ 3,500.00 21.42 $ 110.00 1894 $ 2,500.00 1 $ 10.00 34025 $ 75,000.00 6 5% 33 7% 6 10% 8 $ 1.00 415000 $ 1,000.00 45 PROJECT16 QUANTITY 0.25 $ $ $ $ 160 $ $ $ $ $ $ 4200 $ $ 800 $ 500 $ 500 $ $ 0.2 $ $ 0.2 $ $ 211 $ $ $ $ 1 $ $ $ 15000 $ $ $ $ $ AMOUNT 2,000.00 - - - 2,880.00 - - - - - 4,200.00 - 800.00 3,000.00 1,000.00 - 1,000.00 - 2,000.00 - 23,210.00 - - - 2,900.00 - - 15,000.00 - 58,000.00 5,200.00 63,200.00 PROJECT 17 QUANTITY 0.1 $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ 1 $ $ $ 1 $ $ $ 10000 $ $ -$ $ $ AMOUNT 800.00 - - - - - - - - - - - - - - - - - - - - 2,500.00 - - 700.00 - - 10,000.00 - 14,000.00 1,200.00 15,200.00 PROJECT18 QUANTITY AMOUNT 0.1 $ 800.00 70 $ 1,540.00 50 $ 175.00 100 $ 3,000.00 280 $ 5,040.00 $ - 30 $ 840.00 $ - 25 $ 2,650.00 30 $ 36,000.00 $ - $ - $ - $ - $ - $ - $ - $ - $ - $ - $ - $ - $ - 1 $ 75,000.00 1 $ 7,355.00 $ - 1 $ 14,710.00 $ - $ - $ 147,100.00 $ 13,100.00 $ 160,200.00 PROJECT 19 QUANTITY 0.5 $ $ $ $ 300 $ $ $ $ $ $ 6200 $ $ 1000 $ 600 $ 600 $ $ 0.25 $ 0.25 $ $ 0.5 $ $ $ $ $ 1 $ $ 1 $ 15000 $ $ $ $ $ AMOUNT 4,000.00 - - - 5,400.00 - - - - - 6,200.00 - 1,000.00 3,600.00 1,200.00 - 1,250.00 8,750.00 - 1,750.00 - - - - 2,830.00 - 5,660.00 15,000.00 - 56,600.00 5,000.00 61,600.00 PROJECT20 QUANTITY AMOUNT 0.5 $ 4,000.00 $ - $ - $ - 420 $ 7,560.00 $ - $ - $ - $ - $ - 7500 $ 7,500.00 $ - 1500 $ 1,500.00 750 $ 4,500.00 750 $ 1,500.00 $ - 0.6 $ 3,000.00 0.6 $ 21,000.00 $ - 0.75 $ 2,625.00 $ - $ - $ - $ - 1 $ 5,480.00 $ - 1 $ 10,960.00 40000 $ 40,000.00 $ - $ 109,600.00 $ 9,800.00 $ 119,400.00 I I I I I I I I I I I I I I I I I I I MAY CREEK PLANNING LEVEL · COST ESTIMATE LAST UPDATE: 06/04/2008 MATERIAL DESCRIPTION CLEARING+ GRUBBING+ AND ROADSIDE CLEANUP Clearinn and Grubbinn REMOVAL OF STRUCTURES AND OBSTRUCTIONS Remove Pavement Sawcut Asnhalt Concrete GRADING AND EXCAVATION Structure Excavation (Excavation Underneath Structures) Channel Excavation Fine Gradina MINERAL AGGREGATES Crushed Surface Base Course Boulders PAVEMENT Asohalt Concrete Pavement Patchina DRAINAGE SYSTEMS Rein. Cone. Box Culvert 10' Soan x 4' Rise EROSION CONTROL Hvdro-Seedina Mattina, Jute Mattina, Wood Excelsior Fence, Temoorarv Silt Containment Hiah Visibilitv Fence LANDSCAPING Wet Pond Seedina MISC ITEMS Plantina Preoaration Reveqetation (Cadillac Scenario One\ Reveaetation (Cheanest Scenario Three\ Reveaetation c I ree and Shrub Sunnlementation in Rioarian Corridor' Bioenaineerina Bank Stabilization Beaver Deceiver Bioswale Construction (lndudes Excavation Gradina and Seedina) OTHER ITEMS Temoorarv Bunass Erosion and Sedimentation Control (5%) raffle Control on Minor Roads t7% \ Traffic Control on Maier Roads (10%) land Arnuisition Larae Woodv Debris (Optional' SUBTOTAL CONSTRUCTION COST Sa/es Tax (8.9%) TOTAL CONSTRUCTION COST UNIT AC SY LF CY CY CY TN TN TN LF SF SF SF LF LF SF AC AC AC AC LF EA SF LS LS LS LS $ EA P:\10\10791005\00\Finals\December 2008 Final Draft\Appendix C\Appendix C.xls TOTAL UNIT PRICE QUANTITY $ 8,000.00 14.05 $ 22.00 420 $ 3.50 300 $ 30.00 1678 $ 18.00 28668 $ 25.00 2940 $ 28.00 3980 $ 60.00 305 $ 106.00 150 $ 1,200.00 180 $ 1.00 146900 $ 1.50 1000 $ 1.00 20000 $ 6.00 14275 $ 2.00 14275 $ 3.00 5100 $ 5,000.00 17.28 $ 35,000.00 14.73 $ 10,000.00 6.05 $ 3,500.00 21.42 $ 110.00 1894 $ 2,500.00 1 $ 10.00 34025 $ 75,000.00 6 5% 33 7% 6 10% 8 $ 1.00 415000 $ 1,000.00 45 PROJECT21 QUANTITY AMOUNT 1 $ 8,000.00 $ - $ - $ - 3440 $ 61,920.00 $ - $ - $ - $ - $ - 18000 $ 18,000.00 $ - 3000 $ 3,000.00 1800 $ 10,800.00 1800 $ 3,600.00 $ - 4.2 $ 21,000.00 4.2 $ 147,000.00 $ - 5 $ 17,500.00 $ - $ - $ - $ - 1 $ 16,620.00 $ - $ - 25000 $ 25,000.00 $ - $ 332,400.00 L___1!l,600.00 $ 362,000.00 PROJECT22 QUANTITY AMOUNT 1.3 $ 10,400.00 $ - $ - $ - 1040 $ 18,720.00 $ - $ - $ - $ - $ - $ - $ - $ - $ - $ - $ - 2 $ 10,000.00 2 $ 70,000.00 $ - 4.75 $ 16,625.00 $ - $ - $ - $ - 1 $ 7,935.00 $ - $ - 25000 $ 25,000.00 $ - $ 158,700.00 $ 14,100.00 $ 172,800.00 PROJECT 23 QUANTITY 0.1 $ $ $ $ $ 310 $ $ $ $ $ $ $ $ $ $ 2100 $ 0.1 $ 0.1 $ $ $ $ $ $ $ 1 $ 5000 $ $ $ $ $ l $ AMOUNT 800.00 - - - - 7,750.00 - - - - - - - - - 6,300.00 500.00 3,500.00 - - - - - - 1,255.00 - - 5,000.00 - 25,100.00 2,200.00 27,300.00 PROJECT24 QUANTITY 1 $ $ $ $ 560 $ $ $ $ $ $ 15000 $ $ 2000 $ 1500 $ 1500 $ $ 0.2 $ 0.2 $ $ $ $ $ $ $ 1 $ 10000 $ $ $ $ $ l $ AMOUNT 8,000.00 - - - 10,080.00 - - - - - 15,000.00 - 2,000.00 9,000.00 3,000.00 - 1,000.00 7,000.00 - - - - - - 3,425.00 - - 10,000.00 - 68,500.00 6,100.00 74,600.00 PROJECT25 QUANTITY AMOUNT 0.1 $ 800.00 70 $ 1,540.00 50 $ 175.00 100 $ 3,000.00 $ - $ - 30 $ 840.00 $ - 25 $ 2,650.00 30 $ 36,000.00 $ - $ - $ - $ - $ - $ - $ - $ - $ - $ - $ - $ - $ - 1 $ 75,000.00 1 $ 7,355.00 $ - 1 $ 14,710.00 5000 $ 5,000.00 $ - $ 147,100.00 $ 13,100.00 $ 160,200.00 I I I I I I I I I I I I I I I I I I I MAY CREEK PLANNING LEVEL -COST EST/MA TE LAST UPDATE: 06/04/2008 MATERIAL DESCRIPTION CLEARING+ GRUBBING+ AND ROADSIDE CLEANUP Clearirn:1 and Grubbinn REMOVAL OF STRUCTURES AND OBSTRUCTIONS Remove Pavement Sawcut Asnhalt Concrete GRADING AND EXCAVATION Structure Excavation (Excavation Underneath Structures\ Channel Excavation Fine Gradina MINERAL AGGREGATES Crushed Surface Base Course Boulders PAVEMENT sohalt Concrete Pavement Patchina DRAINAGE SYSTEMS Rein. Cone. Box Culvert 10' Scan x 4' Rise EROSION CONTROL Hvdro-Seedinn Mattina, Jute Mattinq, Wood Excelsior Fence, Temoorarv Silt Containment Hioh Visibilitv Fence LANDSCAPING Wet Pond Seedina MISC ITEMS Plantina Preoaration Reveaetation (Cadillac Scenario One\ Revenetation (Cheanest Scenario Three\ Reveaetation flree and Shrub Suoolementation in Rioarian Corridor) Bioencineerino Bank Stabilization Beaver Deceiver Bioswale Construction (Includes Excavation Gradina and Seedincif OTHER ITEMS T emnorarv B""'ass Erosion and Sedimentation Control (5%) Traffic Control on Minor Roads 17% \ Traffic Control on Maier Roads (10%\ Land Arnuisition Larae Woodv Debris (Ootional\ SUBTOTAL CONSTRUCT/ON COST Sales Tax (8.9%) TOTAL CONSTRUCT/ON COST P:\10\10791005\00\Finals\December 2008 Final D~ft\Appendix C\Appendix C.xls UNIT AC SY LF CY CY CY TN TN TN LF SF SF SF LF LF SF AC AC AC AC LF EA SF LS LS LS LS $ EA TOTAL UNIT PRICE QUANTITY $ 8,000.00 14.05 $ 22.00 420 $ 3.50 300 $ 30.00 1678 $ 18.00 28668 $ 25.00 2940 $ 28.00 3980 $ 60.00 305 $ 106.00 150 $ 1,200.00 180 $ 1.00 146900 $ 1.50 1000 $ 1.00 20000 $ 6.00 14275 $ 2.00 14275 $ 3.00 5100 $ 5,000.00 17.28 $ 35,000.00 14.73 $ 10,000.00 6.05 $ 3,500.00 21.42 $ 110.00 1894 $ 2,500.00 1 $ 10.00 34025 $ 75,000.00 6 5% 33 7% 6 10% 8 $ 1.00 415000 $ 1,000.00 45 PROJECT 26 QUANTITY AMOUNT 0.1 $ 800.00 70 $ 1,540.00 50 $ 175.00 100 $ 3,000.00 $ - $ - 30 $ 840.00 $ - 25 $ 2,650.00 30 $ 36,000.00 $ - $ - $ . $ . $ - $ . $ . $ . $ . $ . $ . $ . $ . 1 $ 75,000.00 1 $ 7,355.00 $ - 1 $ 14,710.00 5000 $ 5,000.00 $ - $ 147,100.00 _$ _13,100.00 $ 160,200.00 PROJECT27 QUANTITY AMOUNT 0.1 $ 800.00 70 $ 1,540.00 50 $ 175.00 100 $ 3,000.00 $ . $ . 30 $ 840.00 $ . 25 $ 2,650.00 30 $ 36,000.00 $ - $ . $ . $ - $ . $ . $ . $ . $ - $ - $ . $ - $ - 1 $ 75,000.00 1 $ 7,355.00 $ . 1 $ 14,710.00 5000 $ 5,000.00 $ - $ 147,100.00 l_J..1.100.00 $ 160,200.00 PROJECT 28 QUANTITY 0.75 $ $ $ $ 615 $ $ $ $ $ $ $ $ $ $ $ $ 0.75 $ 0.75 $ $ 2.2 $ $ $ $ $ 1 $ 1 $ 15000 $ $ $ -$ $ $ AMOUNT 6,000.00 . . . 11,070.00 . . . . - . . . . . . 3,750.00 26,250.00 . 7,700.00 . - - - 3,965.00 5,551.00 - 15,000.00 . 79,300.00 7,100.00 86,400.00 PROJECT 29 QUANTITY AMOUNT 0.25 $ 2,000.00 $ - $ . $ . $ . $ - $ - $ - $ . $ . $ . $ . $ . $ . $ - $ . 1.13 $ 5,650.00 1.13 $ 39,550.00 $ - $ - $ . $ . 22225 $ 222,250.00 $ - 1 $ 15,880.00 1 $ 22,232.00 10000 $ - $ 10,000.00 $ - $ 317,600.00 $ _ 28~300.00 $ 345,900.00 I I I I I I I I I I I I I I I I I I I MAY CREEK PLANNING LEVEL • COST ESnMATE LAST UPDATE: 06/04/2008 MATERIAL DESCRIPTION CLEARING+ GRUBBING+ AND ROADSIDE CLEANUP Clearina and Grubbinn REMOVAL OF STRUCTURES AND OBSTRUCTIONS Remove Pavement Sawcut Asnhalt Concrete GRADING AND EXCAVA TIDN Structure Excavation tExcavation Underneath Structures\ Channel Excavation Fine Gradina MINERAL AGGREGATES Crushed Surface Base Course Boulders PAVEMENT Asohalt Concrete Pavement Patchina DRAINAGE SYSTEMS Rein. Cone. Box Culvert 1 O' Scan x 4' Rise EROSION CONTROL Hvdro~Seedina Mattina, Jute Mattinn, Wood Excelsior Fence, Temnorarv Silt Containment Hiah Visibilitv Fence LANDSCAPING \/Vet Pond Seedina MISC ITEMS Plantina Preoaration Reveaetation (Cadillac Scenario One\ Revenetation fCheanest Scenario Three\ Reveaetation lTree and Shrub Sunnlementation in Rioarian Corridor) Bioenaineerina Bank Stabilization Beaver Deceiver Bioswale Construction <Includes Excavation Gradina and Seedinci\ OTHER ITEMS emoorarv 9unass Erosion and Sedimentation Control (5%) !Traffic Control on Minor Roads (7%\ raffic Control on Maior Roads (10% \ Land Ar-nuisition Larae Woodv Debris (Ootional) SUBTOTAL CONSTRUCT/ON COST Sales Tax (8.9%) TOTAL CONSTRUCT/ON COST P:\10\10791005\00\Finals\December 2008 Final Draft\Appendix C\Appendix C.xls UNIT AC SY LF CY CY CY TN TN TN LF SF SF SF LF LF SF AC AC AC AC LF EA SF LS LS LS LS $ EA TOTAL UNIT PRICE QUANTITY $ 8,000.00 14.05 $ 22.00 420 $ 3.50 300 $ 30.00 1678 $ 18.00 28668 $ 25.00 2940 $ 28.00 3980 $ 60.00 305 $ 106.00 150 $ 1,200.00 180 $ 1.00 146900 $ 1.50 1000 $ 1.00 20000 $ 6.00 14275 $ 2.00 14275 $ 3.00 5100 $ 5,000.00 17.28 $ 35,000.00 14.73 $ 10,000.00 6.05 $ 3,500.00 21.42 $ 110.00 1894 $ 2,500.00 1 $ 10.00 34025 $ 75,000.00 6 5% 33 7% 6 10% 8 $ 1.00 415000 $ 1,000.00 45 INEFF. FLOW PROJECT 1 QUANTITY AMOUNT 0.3 $ 2,400.00 $ - $ - 237 $ 7,110.00 3334 $ 60,012.00 371 $ 9,275.00 1000 $ 28,000.00 20 $ 1,200.00 $ - $ - 6000 $ 6,000.00 $ - $ - 550 $ 3,300.00 550 $ 1,100.00 $ - $ - $ - 0.95 $ 9,500.00 0. 11 $ 385.00 $ - $ - $ - $ - 1 $ 8,250.00 $ - 1 $ 16,500.00 12 $ - $ 12,000.00 $ 165,000.00 _$~_14/00.00 $ 179,700.00 INEFF. FLOW PROJECT 2 QUANTITY 0.2 $ $ $ 201 $ 601 $ 67 $ 450 $ 10 $ $ $ 2500 $ $ $ 250 $ 250 $ $ $ $ 0.4 $ 0.05 $ $ $ $ $ 1 $ 1 $ $ $ 5 $ -$ i $ AMOUNT 1,600.00 - - 6,030.00 10,818.00 1,675.00 12,600.00 600.00 - - 2,500.00 - - 1,500.00 500.00 - - - 4,000.00 175.00 - - - - 2,670.00 3,738.00 - - 5,000.00 53,400.00 4,800.00 58,200.00 INEFF. FLOW PROJECT 3 QUANTITY AMOUNT 0.5 $ 4,000.00 $ - $ - 140 $ 4,200.00 8306 $ 149,508.00 923 $ 23,075.00 1750 $ 49,000.00 30 $ 1,800.00 $ - $ - 12500 $ 12,500.00 $ - $ - 950 $ 5,700.00 950 $ 1,900.00 $ - $ - $ - 1.6 $ 16,000.00 0.2 $ 700.00 $ - $ - $ - $ - 1 $ 16,385.00 1 $ 22,939.00 20 $ - $ - $ 20,000.00 $ 327,700.00 $ 2!1,200.00 $ 356,900.00 INEFF. FLOW PROJECT 4 QUANTITY AMOUNT 0.2 $ 1,600.00 $ - $ - 500 $ 15,000.00 4357 $ 78,426.00 484 $ 12,100.00 600 $ 16,800.00 10 $ 600.00 $ - $ - 5000 $ 5,000.00 $ - $ - 325 $ 1,950.00 325 $ 650.00 $ - $ - $ - 0.55 $ 5,500.00 0.06 $ 210.00 $ - $ - $ - $ - 1 $ 8,580.00 $ - 1 $ 17,160.00 $ - 8 $ 8,000.00 $ 171,600.00 $ 15,300.00 $ 186,900.00 I I I I I I I I I I I I I I I I I I I GEoENGINEER~ APPEND/XO REPORT LIMITATIONS AND GUIDELINES FOR USE ,, ' ~-. -~ ,; ' ;,,. '' ~" ~' \.. • ,, \ ' ' I I .1 I I I I I I I I I I I I I I I I APPENDIX D REPORT LIMITATIONS AND GUIDELINES FOR USE 1 This appendix provides infonnation to help you manage your risks with respect to the use of this report. GEOTECHNICAL SERVICES ARE PERFORMED FOR SPECIFIC PURPOSES, PERSONS AND PROJECTS This report has been prepared for exclusive use by King County, and their authorized agents. This report may be made available to members of the project team. This report is not intended for use by others, and the information contained herein is not applicable to other sites. GeoEngineers structures our services to meet the specific needs of our clients. For example, a geotechnical or geologic study conducted for a civil engineer or architect may not fulfill the needs of a construction contractor or even another civil engineer or architect that are involved in the same project. Because each geotechnical or geologic study is unique, each geotechnical engineering or geologic report is unique, prepared solely for the specific client and project site. Our report is prepared for the exclusive use of our Client. No other party may rely on the product of our services unless we agree in advance to such reliance in writing. This is to provide our firm with reasonable protection against open-ended liability claims by third parties with whom there would otherwise be no contractual limits to their actions. Within the limitations of scope, schedule and budget, our services have been executed in accordance with our Agreement with the Client and generally accepted geotechnical practices in this area at the time this report was prepared. This report should not be applied for any purpose or project except the one originally contemplated. A GEOTECHNICAL ENGINEERING OR GEOLOGIC REPORT IS BASED ON A UNIQUE SET OF PROJECT•SPECIFIC FACTORS This Drainage and Restoration Plan for May Creek has been prepared for the King County. GeoEnginecrs considered a number of unique, project-specific factors when establishing the scope of services for this project and report. Unless GeoEngincers specifically indicates otherwise, do not rely on this report if it was: • not prepared for you, • not prepared for your project, o not prepared for the specific site explored, or • completed before important project changes were made. For example, changes that can affect the applicability of this report include those that affect: • the function of the proposed structure; o elevation, configuration, location, orientation or weight of the proposed structure; • composition of the design team; or • project ownership. If important changes are made after the date of this report, Geo Engineers should be given the opportunity to review our interpretations and recommendations and provide written modifications or confirmation, as appropriate. 1 Developed based on material provided by ASFE, Professional Finns Practicing in the Geoscienccs; www.asfe.org. File No. 1()791-005-00 December 19, 2008 D-1 GEOENGIN&&RS _ai SUBSURFACE CONDITIONS CAN CHANGE This geotechnical or geologic report is based on conditions that existed at the time the study was performed. The findings and conclusions of this report may be affected by the passage of time, by manmade events such as construction on or adjacent to the site, or by natural events such as floods, earthquakes, slope instability or groundwater fluctuations. Always contact GeoEngineers before applying a report to determine if it remains applicable. MOST GEOTECHNICAL AND GEOLOGIC FINDINGS ARE PROFESSIONAL OPINIONS Our interpretations of subsurface conditions are based on field observations from widely spaced sampling locations at the site. Site exploration identifies subsurface conditions only at those points where subsurface tests are conducted or samples are taken. GeoEngineers reviewed field and laboratory data and then applied our professional judgment to render an opinion about subsurface conditions throughout the site. Actual subsurface conditions may differ, sometimes significantly, from those indicated in this report. Our report, conclusions and interpretations should not be construed as a warranty of the subsurface conditions. GEOTECHNICAL ENGINEERING REPORT RECOMMENDATIONS ARE NOT FINAL Do not over-rely on the preliminary construction recommendations included in this report. These recommendations are not final, because they were developed principally from GeoEngineers' professional judgment and opinion. GeoEngineers' recommendations can be finalized only by observing actual subsurface conditions revealed during construction. GeoEngineers cannot assume responsibility or liability for this report's recommendations ifwe do not perform construction observation. Sufficient monitoring, testing and consultation by GeoEngineers should be provided during construction to confirm that the conditions encountered are consistent with those indicated by the explorations, to provide recommendations for design changes should the conditions revealed during the work differ from those anticipated, and to evaluate whether or not earthwork activities are completed in accordance with our recommendations. Retaining GeoEngineers for construction observation for this project is the most effective method of managing the risks associated with unanticipated conditions. A GEOTECHNICAL ENGINEERING OR GEOLOGIC REPORT COULD BE SUBJECT TO MISINTERPRETATION Misinterpretation of this report by other design team members can result in costly problems. You could lower that risk by having GeoEngineers confer with appropriate members of the design team after submitting the report. Also retain Geo Engineers to review pertinent elements of the design team's plans and specifications. Contractors can also misinterpret a geotechnical engineering or geologic report. Reduce that risk by having GeoEngineers participate in pre-bid and preconstruction conferences, and by providing construction observation. GIVE CONTRACTORS A COMPLETE REPORT AND GUIDANCE Some owners and design professionals believe they can make contractors liable for unanticipated subsurface conditions by limiting what they provide for bid preparation. To help prevent costly problems, give contractors the complete geotechnical engineering or geologic report, but preface it with a clearly written letter of transmittal. In that letter, advise contractors that the report was not prepared for purposes of bid development and that the report's accuracy is limited; encourage them to confer with GcoEngineers and/or to conduct additional study to obtain the specific types of information they need or prefer. A pre- bid conference can also be valuable. Be sure contractors have sufficient time to perform additional study. File No. 1079/.005·00 December /9, 2008 D-2 GEOENGINEU~ I I I I I I I I I I I I I I I , -1 I I I I I I I I I I I I I I I I I I Only then might an owner be in a pos11Ion to give contractors the best information available, while requiring them to at least share the financial responsibilities stemming from unanticipated conditions. Further, a contingency for unanticipated conditions should be included in your project budget and schedule. CONTRACTORS ARE RESPONSIBLE FOR SITE SAFETY ON THEIR OWN CONSTRUCTION PROJECTS Our geotechnical recommendations are not intended to direct the contractor's procedures, methods, schedule or management of the work site. The contractor is solely responsible for job site safety and for managing construction operations to minimize risks to on-site personnel and to adjacent properties. READ THESE PROVISIONS CLOSELY Some clients, design professionals and contractors may not recognize that the geoscience practices (geotechnical engineering or geology) are far less exact than other engineering and natural science disciplines. This lack of understanding can create unrealistic expectations that could lead to disappointments, claims and disputes. GeoEngineers includes these explanatory "limitations" provisions in our reports to help reduce such risks. Please confer with Geo Engineers if you are unclear how these "Report Limitations and Guidelines for Use" apply to your project or site. GEOTECHNICAL, GEOLOGIC AND ENVIRONMENTAL REPORTS SHOULD NOT BE INTERCHANGED The equipment, techniques and personnel used to perform an environmental study differ significantly from those used to perform a geotechnical or geologic study and vice versa. For that reason, a geotechnical engineering or geologic report does not usually relate any environmental findings, conclusions or recommendations; e.g., about the likelihood of encountering underground storage tanks or regulated contaminants. Similarly, environmental reports are not used to address geotechnical or geologic concerns regarding a specific project. BIOLOGICAL POLLUTANTS GeoEngineers' Scope of Work specifically excludes the investigation, detection, prevention or assessment of the presence of Biological Pollutants. Accordingly, this report docs not include any interpretations, recommendations, findings, or conclusions regarding the detecting, assessing, preventing or abating of Biological Pollutants and no conclusions or inferences should be drawn regarding Biological Pollutants, as they may relate to this project. The term "Biological Pollutants" includes, but is not limited to, molds, fungi, spores, bacteria, and viruses, and/or any of their byproducts. If Client desires these specialized services, they should be obtained from a consultant who offers services in this specialized field. File No. 1079/-005-00 December 19, 200R D-3 GEOENGIN&EAS_y} I I I I I I I I I I I I I I I I I I I ta King County Department of Transportation Road Services Division Engineering Services Section King Street Center 201 South Jackson Street Seattle, WA 98104-3856 August 4, 2011 C/6.. . •Jr 01 ~ent Planning Oivfs/o~r, FE8 1 2 2013 TO: Don Althauser, Managing Engineer, Water and Land Resources Division, Stormwater Services Section FM: Bill Kerschke, Environmental Scientist, Road Services Division, Engineering Services Section .~ Julia Turney, Environmental Engineer, Road Services Division, Enginee~ · O Services Section RE: May Creek Drainage Improvement Project (9A1205) Post-Construction Erosion Monitoring Plan -Downstream of 148th Avenue SE Introduction This memo was prepared to address comments from the Washington Department of Ecology and the public on the May Creek Drainage Improvement Project. This memo describes the post-construction erosion monitoring plan for the reach of May Creek downstream of 148th Avenue SE. Project components, including in-stream sediment and vegetation removal between mile 4.3 and 4.9 of May Creek, have raised public concern that properties downstream of 148th Avenue SE may be impacted by post-project changes in stream bed and/or bank erosion. Studies already completed by King County Water and Land Resources indicate that the project will not effect downstream erosion (WRLD); however, King County is committed to confirming this assertion post-project. The intent of this memo is to describe an approach for a post-construction monitoring that will evaluate project-related changes in erosion in May Creek between I 48th Avenue SE and the Coal Creek Parkway SE. This reach is often referred to as the "canyon reach" of May Creek. Background Studies Studies were completed to evaluate downstream impacts for the proposed May Creek project. A sediment transport study (Anchor 2009) was implemented to analyze the erosion threshold in May Creek between 148th Avenue SE and Coal Creek Parkway SE. This study included selection of a study reach, data collection, analysis, preparation of a HEC-RAS model of the reach, and evaluation of the discharge at which the bed sediment begins to move. According to the sediment mobility evaluation, the threshold of motion occurs between approximately 70 to 350 cubic feet per second (cfs). Don Althauser August 4, 2011 Page 2 A hydraulic and hydrologic modeling analysis (King County 20 I 0) was completed for the project that noted, post-construction, a minimal increase in surface water elevations and water velocities are predicted in the downstream canyon reach. This minimal increase is due primarily to existing hydrologic control points just downstream of the project area (at approximately River Mile 4.2 to 4.3). The hydraulic and hydrologic study concluded that effectively no significant change between existing and proposed conditions at the modeled flood frequency would occur. In addition, at higher flow rates, even less differences between pre-and post conditions would occur. Furthermore, the proposed May Creek Drainage Improvement Project features, including the installation of native plant buffers, removal of in-stream vegetation and sediment, construction of sediment management features in Long Marsh Creek, and excavation of alcoves downstream of 148th A venue SE, are estimated to result in a net reduction in fine sediment and organic material reaching Marsh Creek within the project area. Fine sediment, which currently accumulates in the channel and moves downstream during high-flow events, is anticipated to move downstream at a more constant rate post-construction. Post-Construction Monitoring Plan King County WLRD proposes to implement a five-year monitoring plan post- construction between 148th A venue SE and Coal Creek Parkway SE to address the concerns of increased post-project erosion in the canyon reach of May Creek. The monitoring effort will build upon prior and ongoing monitoring efforts implemented during the Sediment Transport Study (Anchor 2009) and proposed monitoring in the May Creek Canyon Reach Draft Monitoring Plan (Anchor 2010). Current Downstream Erosion Monitoring Efforts Anchor Engineering was retained by King County to develop the May Creek Canyon Reach Draft Monitoring Plan (Anchor 2010) for the reach downstream of 148th Avenue SE. In 20 IO and 2011, King County WRLD implemented the May Creek Canyon Reach Draft Monitoring Plan to collect baseline data (King County 2011). The intent of the May Creek Canyon Reach Draft Monitoring Plan is to gather supplemental data to be used to identify and document potential impacts from the upstream project implementation, building upon information gained from the Sediment Transport Study (Anchor 2009). The proposed monitoring from this plan includes installation of a water level sensor, bed pins and bed hooks, and channel profile surveys to document existing conditions that allow for identification of changes to the channel bed. The hydrologic elevations and physical conditions of a stream channel enable the identification of changes in the character of the stream to be monitored. Surveyed physical characteristics of the May Creek channel enabled evaluation of changes in channel cross-sectional geometry and provided information on sediment movement through the reach. The sediment mobility evaluation in the Sediment Transport Study (Anchor 2009) identified a threshold of motion to occur between approximately 70 and 350 cubic feet per second (cfs). Therefore, it was determined that monitoring should occur at events I I I I D I I I I I I I I I • I I I I I I I I I I I I I I I I I I I I I I I Don Althauser August 4, 2011 Page 3 greater than approximately 70 cfs. Detailed data collection and monitoring protocols and descriptions of monitoring sites can be found in the attached May Creek Canyon Reach Draft Monitoring Plan (Anchor 20 I 0) and are summarized below. The monitoring sites and potential monitoring elements at each site are identified in Table I below, which has been included for reference from the attached May Creek Canyon Reach Draft Monitoring Plan (Anchor 2010). The monitoring site locations are shown in Figure I in the attached May Creek Canyon Reach Draft Monitoring Plan (Anchor 2010); however, please note that Figure I in the attached report contains an error, showing Tract A and D transposed. In Figure I of the attached, the right and left bank are referenced looking downstream. Also, please note that since preparation of the May Creek Canyon Reach Draft Monitoring Plan (Anchor 2010), King County's access to Tract A (Broussard property) was revoked by the property owner. In addition, monitoring at Station 1 in the Sediment Transport Study (Anchor 2009) was discontinued due to braided channel flow conditions and recurring vandalism at the site. Therefore, continued monitoring efforts will occur on only six sites. T bl 1 M a e omtorma s· 1tes an d Eff orts Monitoring Site Monitorin!I Elements Bank Location PT BH BP Riaht Left Parhaniemi/Gambini' X X X X X Tract A (Broussard)" X X X Duffus Right Bank X X Duffus Left Bank X Tract D X X X Cole X X X Stonegate Tract X X X * Referred to as Site 2 in the Sediment Transport Study (Anchor 2009) ** Proposed monitoring at this site was subsequently cancelled due to access issues. PT= Pressure transducer, BH= Bed hooks, BP= bank pins. Set of Hook/Pins 1 1 3 1 2 2 2 A cross-section survey is to be completed at every site for each transect (bank pins and/or bed hooks). In addition, Gage 378 (Figure I in attached May Creek Canyon Reach Draft Monitoring Plan) is to be reconciled due to inconsistencies in the stage flow relationship. Reconciliation of the gage will allow for the development of a long-term, site specific data record that can be used to improve the accuracy of the sediment mobility evaluation and predictions about future channel erosion. The monitoring described in the May Creek Canyon Reach Draft Monitoring Plan (Anchor 2010) will continue until the project is constructed and for five years post- construction. Don Althauser August 4, 2011 Page4 Additional Proposed Erosion Monitoring Downstream In addition to the above referenced monitoring from the May Creek Canyon Reach Draft Monitoring Plan (Anchor 2010), King County proposes to install scour and fill chains (Harrelson et al. 1994) at each of the six sites (property owner permission dependant) in Table I to monitor sediment movement. These sites provide some baseline cross section and erosion data from past monitoring. Scour chains are steel chains implanted in streambeds to measure erosion and deposition of sediment over a period of time. The scour chains will allow for the evaluation of movement of bed material at threshold storm events (70 cfs) and sediment deposition as waters subside. This information cannot be obtained from cross-section surveys or the other conventional methods already proposed. Recording the amount of scour and fill at the sample locations provides information describing how sediment is moving through the lower system. To measure erosion and deposition, scour chains (Figure I) and metal chains anchored onto metal plates and buried vertically in the channel bed, would be installed in the streambeds at each of the monitoring sites. When sediment is eroded from the streambed during a flood event, the exposed chain falls flat, forming a bend. Sediment deposition that would occur as waters receded, would rebury the chains. The amount of bed erosion is determined by comparing the original length of chain buried to the length left below the bend. The amount of deposition is identified by measuring the depth of sediment above the bend. Two to seven scour chains will be installed at each of the six monitoring sites and their locations documented for future relocation (survey and photograph). Scour chains will be installed in areas where the greatest amount of erosion is anticipated from previous monitoring, thalweg location, and bed erosion. Cross section data will be used to identify the elevation of bed material at each site and the length of each buried chain will be recorded, allowing calculation of changes in bed elevation when the scour chains are monitored over time. After each measured flow event, chains will be excavated to measure erosion and deposition and then straightened and reburied. Procedure/or Inserting Scour Chains (from Reclamation 2008) 1. Implant chains with colored cork floats. 2. Slip duck bill anchor around the bottom of the inserter. 3. Hold chain as taut as possible. 4. Hold inserter vertical at bed surface. 5. Pound the top of the inserter into the bed/bank with a sledge hammer until the inserter handle is at the water surface, or the chain is sufficiently buried (The anchor should be buried at least 25 cm, or it won't set properly.) 6. Set the anchor by pulling back and forth on the inserter and twisting. 7. Once anchor is set, pull out the inserter using a pipe wrench. I I I I D 0 D I I I D I I I I u u I I I I I I I I I I I I I I I I I I 'I Don Althauser August 4, 2011 Page 5 Pull up on the chain remove any slack. 8. After chain is set, replace any gravel that may have created a hole around the chain; then attach hog ring to the first link that is exposed at the bed surface. 9. Measure the chain length from the hog ring to the end of the chain, and record. I 0. Survey the bed surface at the position of the chain using total station. Maximum Erosion and Deposition (scour and fill) Calculation ........... --- Scour: I) Difference in elevation from the·hog ring to the kink, calculated from the number of links ( each link was 35 millimeters [mm] long). 2) Difference in elevation calculated from the surveys: elevation at the time of installation minus elevation of kink during measurement. Fill: Elevation of the surface at final measurement minus elevation of the kink. ....... ·~- """"'- 9 \.Uat1~ Figure 1: Schematic of Scour Chain (Lyle, 1991) and Installation Process (USEPA) Don Althauser August 4, 2011 Page 6 References King County. 2011. May Creek Baseline Monitoring (Preliminary Draft) -Implementing May Creek Canyon Reach Draft Monitoring Plan (Anchor 2010). King County. 2010. Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project. Prepared by Jeff Burkey, King County Department of Natural Resources and Parks, Science Section. Prepared for Stormwater Services Section, Capital Services Unit. December 2010. Available at: http://www.kingcounty.gov/environment/watersheds/cedar-river-lake-wa/may- creek/hydraulic-hydrologic-analyses.aspx Anchor. 2010. May Creek Canyon Reach Draft Monitoring Plan. Prepared by Anchor QEA, LLC for King County Department of Natural Resources and Parks. December 2010. Anchor. 2009. May Creek Sediment Transport Study. Prepared by Anchor QEA, LLC for King County Department ofNatural Resources and Parks. June 2009. Available at: http://www.kingcounty.gov/environment/watersheds/cedar-river-lake- wa/may-creek/sediment-transport-study.aspx Reclamation. 2008. Klamath River Salmon Redd Scour Study, 2007 -2008, Technical Memorandum No. 86-68290-08-02, Technical Service Center, Denver, CO. USDA. 1994. Harrelson, C.C., C.L. Rawlins, and J.P. Potyondy. Stream channel reference sites: An illustrated guide to field technique. General Technical Report RM-245. Nawa, R., & Frissell, C. 1993. Measuring Scour and Fill of Gravel Streambeds with Scour Chains and Sliding-Bead Monitors. North American Journal of Fisheries Management, 13, 634-639. Lisle, Thomas E.; Eads, Rand E. 1991. Methods to measure sedimentation of spawning gravels. Res. Note PSW-411. Berkeley, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture; 7 p. US EPA, Watershed Assessment of River Stability & Sediment Supply (WARSSS), Field Methods and Procedures, downloaded from http://water.epa.gov/scitech/datait/tools/warsss/method.cfrn August 4, 2011. Attachments May Creek Canyon Reach Draft Monitoring Plan (Anchor 2010) D I D I I I I I I I I I I I I I I I I I I I I I I I I I 11 I I I I MAY CREEK CANYON REACH DRAFT MONITORING PLAN MAY CREEK SEDIMENT TRANSPORT STUDY PHASE 4 Prepared for King County Department of Natural Resources and Parks 201 S. Jackson Street, Suite 600 Seattle, Washington 98104-3856 Prepared by Anchor QEA, LLC 1605 Cornwall Avenue Bellingham, Washington 98225 December 2010 I I I I I I I I I I I I I I I I I I I TABLE OF CONTENTS 1 INTRODUCTION .................................................................................................................. 1 2 DATA COLLECTION METHODS AND PROTOCOLS ....................................................... 2 2.1 Monitoring Events ........................................................................................................... 2 2.2 Equipment ........................................................................................................................ 2 2.3 Monitoring Elements ....................................................................................................... 3 2.3.1 Pressure Transducers .................................................................................................. 3 2.3.2 Cross-Section Survey .................................................................................................. 3 2.3.3 Bed Hooks and Bank Pins ......................................................................................... .4 3 MONITORING SITES ............................................................................................................ 6 3.1 Previously-Established Sites ............................................................................................ 6 3.1.1 May Creek Park (Station 1) ........................................................................................ 6 3.1.2 Gage 37B-Coal Creek Parkway ............................................................................... 7 3.1.3 Parhaniemi Property (Station 2) ................................................................................ 7 3.1.4 Tract A (Station 3) ...................................................................................................... 7 3.2 New Monitoring Sites ...................................................................................................... 8 3.2.1 Duffus Property-Left Bank ...................................................................................... 8 3.2.2 Duffus Property-Right Bank ................................................................................... 8 3.2.3 Tract D ........................................................................................................................ 8 3.2.4 Cole Property .............................................................................................................. 8 3.2.5 Stonegate Tract ........................................................................................................... 9 4 SUMMARY .......................................................................................................................... 10 List of Tables Table 1 Summary of Monitoring Elements ....................................................................... 6 List of Figures Figure 1 Proposed Monitoring Locations May Creek Canyon Reach Monitoring Plan May Creek Sediment Transport Study Phase 4 j December 2010 090159-01 I I I I I I I I I I I I I I I I I I I 1 INTRODUCTION Anchor QEA, LLC (Anchor QEA) and KPFF Consulting Engineers were retained by King County (County} to assist in developing a monitoring plan for the Canyon Reach (Reach) of May Creek downstream of 148th Avenue SE. The monitoring effort will gather supplemental data to be used to identify and document potential impacts from upstream project implementation, building upon the prior monitoring effort implemented during Phase I of the project. The following sections of this plan will define elements of the Phase I monitoring effort to be re-implemented, refined, or discontinued. New procedures and elements of the plan will also be described, and new monitoring locations will be identified to build on the data collected in the previous study. The monitoring plan will be implemented by County staff. May Creek Canyon Reach Monitoring Plan May Creek Sediment Transport Study Phase 4 1 December 2010 090159-01 2 DATA COLLECTION METHODS AND PROTOCOLS A data collection and monitoring program was previously developed for the May Creek Sediment Transport Study during Phase I to document baseline conditions and provide data for the sediment mobility analysis. The current scope builds on and refines the methodology performed during Phase I to collect supplemental data. King County personnel will perform monitoring tasks, including completion of monitoring forms and survey. The specific monitoring to be performed at each site is described in Section 3. 2.1 Monitoring Events According to the sediment mobility evaluation during Phase 2, the threshold of motion occurs between approximately 70 and 350 cubic feet per second (cfs). Therefore, each location should be monitored following precipitation events greater than approximately 70 cfs. Because the range of critical discharge is relatively large, one purpose of the site visits is to narrow the range of observed discharges where erosion is observed and no apparent erosion is observed. These data will help to improve the precision of the sediment mobility evaluation. 2.2 Equipment Following is a list of the necessary items for each field visit following initial establishment of monitoring sites: 1. 30 bed hooks (eye bolts) 2. Three 2-foot r,~bar stakes, or more following a large flow event 3. Tape measure (30-foot minimum) 4. Sledge hammer 5. Colored flagging 6. Monitoring forms (spreadsheet printouts) 7. Spray paint 8. Waders or boots 9. Gloves May Creek Canyon Reach Monitonng Plan May Creek Sediment Transpon Study Phase 4 2 December 2010 090159-01 I I I I I I D I I I • I I I I I I I I I I I I I I I I I I I I I I I I I I Monitoring Sites 2.3 Monitoring Elements The following sections describe the various forms of data collection methods that may be implemented throughout the site including installation and monitoring. 2.3.1 Pressure Transducers Pressure transducers (piezometers) with internal data loggers are to be installed in the creek channel at the locations specified to collect hourly and daily water surface elevation data. Transducer data shall be collected periodically by County personnel. 2.3.2 Cross-Section Survey Each transect at a monitoring station shall include a left and right bank re bar with cap, placed such that a line between the re bar is perpendicular to the flow of the creek. The rebar caps represent benchmark points along the specific transect; surveyed points will be relative to the left bank re bar cap. The re bar shall be placed outside of the possible extent of erosion or flooding such that there is no risk of its position being compromised. Upon initial installation of the monitoring elements, a cross-section survey shall be completed of each monitoring site. A laser-level and survey rod may be used for the survey to produce a cross-section relative to the left bank re bar cap. This control point should be tied into a known vertical coordinate system, such as North American Vertical Datum (NA VD) 88. All measured distances during the cross-section survey shall be measured from the left bank rebar benchmark to produce a cross-section survey looking downstream. Survey shall be collected across the channel between the left bank to the right bank rebar; if a level and rod is used, a string or tape may be placed between the rebar to ensure a straight, consistent section. Survey points shall be collected at no greater than 1-foot changes in ground elevation, except at near-vertical banks where major grade breaks may be surveyed. Collecting survey at this resolution will allow for detection of minor changes in the channel cross-section. The position of each bed hook shall also be included in the survey and noted in the description. In addition to the channel cross-section, the survey crew shall collect a point in the lowest part of the channel bed at approximately 50 and 100 feet upstream and downstream of the May Creek Canyon Reach Monitoring Plan May Creek Sediment Transport Study Phase 4 3 December 2010 090159-01 Monitoring Sites rebar. These points will be used to represent the local gradient at the monitoring site, and provide preliminary indication of bedform modification within the reach. The cross-section and gradient survey shall be repeated per the process above when one or more of the following conditions apply: o When significant erosion or deposition at the monitoring location is evident from dislodgement or covering of bank pins or bed hooks o Following a flood event of 2-year or greater recurrence interval, approximately 200 cfs o At the end of the monitoring period 2.3.3 Bed Hoo.l<s and Bank Pins Each monitoring location shall include either bed hooks, bank pins, or both to monitor erosion or deposition of the bed and erosion of the banks. The location and condition of bed hooks and bank pins will be documented during each site visit. Bed hooks consist of eye bolts driven into the streambed at 2-foot intervals along a transect across the channel. Colored flagging shall be attached to each eye bolt to improve visibility during monitoring. Bed hooks are recommended in locations suitable to monitoring bed movement. Bank pins shall be distributed within the study area in locations where bank erosion is likely to occur prior to bed movement and shall consist of 2-foot lengths of re bar driven flush into the bank along a transect. At least four lengths of re bar should be installed for each location specified for bank pins. Bank pins should be installed in locations where the greatest amount of erosion can be expected; therefore, it is important that the locations are refined in the field by personnel familiar with site conditions. After each critical flow event, monitoring locations shall be investigated for the presence or absence of each of the bed hooks (eye bolts) or exposure of the bank pins (rebar). Any change to these features shall be measured and documented using the monitoring forms. The protocol for each monitoring event is provided below. Note: Bed hooks are included at one site only, see Sect.ion 3.1.3. 1. Assess the site for obvious storm effects or potential vandalism and note in the site conditions sections of the monitoring form. May Creek Canyon Reach Moniton'ng Plan May Creek Sediment Transport Study Phase 4 4 December 2010 090159-01 I I I I I I I g I I I I I I I I I I I I I I I I I I I I I I GEOENGINEER~ APPEND/XO REPORT LIMITATIONS AND GUIDELINES FOR USE I I I I I I I I I I I I I I I I I I I APPENDIX D REPORT LIMITATIONS AND GUIDELINES FOR USE 1 This appendix provides information to help you manage your risks with respect to the use of this report. GEOTECHNICAL SERVICES ARE PERFORMED FOR SPECIFIC PURPOSES, PERSONS AND PROJECTS This report has been prepared for exclusive use by King County, and their authorized agents. This report may be made available to members of the project team. This report is not intended for use by others, and the information contained herein is not applicable to other sites. GeoEngineers structures our services to meet the specific needs of our clients. For example, a geotechnical or geologic study conducted for a civil engineer or architect may not fulfill the needs of a construction contractor or even another civil engineer or architect that are involved in the same project. Because each geotechnical or geologic study is unique, each geotechnical engineering or geologic report is unique, prepared solely for the specific client and project site. Our report is prepared for the exclusive use of our Client. No other party may rely on the product of our services unless we agree in advance to such reliance in writing. This is to provide our finn with reasonable protection against open-ended liability claims by third parties with whom there would otherwise be no contractual limits to their actions. Within the limitations of scope, schedule and budget, our services have been executed in accordance with our Agreement with the Client and generally accepted geotechnical practices in this area at the time this report was prepared. This report should not be applied for any purpose or project except the one originally contemplated. A GEOTECHNICAL ENGINEERING OR GEOLOGIC REPORT IS BASED ON A UNIQUE SET OF PROJECT-SPECIFIC FACTORS This Drainage and Restoration Plan for May Creek has been prepared for the King County. GeoEngineers considered a number of unique, project-specific factors when establishing the scope of services for this project and report. Unless GeoEngincers specifically indicates otherwise, do not rely on this report if it was: • not prepared for you, • not prepared for your project, • not prepared for the specific site explored, or • completed before important project changes were made. For example, changes that can affect the applicability of this report include those that affect: • the function of the proposed structure; • elevation, configuration, location, orientation or weight of the proposed structure; • composition of the design team; or o project ownership. lfimportant changes are made after the date of this report, GeoEngineers should be given the opportunity to review our interpretations and recommendations and provide written modifications or confirmation, as appropriate. 1 Developed based on material provided by ASFE, Professional Firms Practicing in the Geosciences; www.asfe.org. File No. /079/-0()5-00 Deccmher /9, 200R D-1 GEOENGINEERSY SUBSURFACE CONDITIONS CAN CHANGE This geotechnical or geologic report is based on conditions that existed at the time the study was performed. The findings and conclusions of this report may be affected by the passage of time, by manmade events such as construction on or adjacent to the site, or by natural events such as floods, earthquakes, slope instability or groundwater fluctuations. Always contact GeoEngineers before applying a report to detennine if it remains applicable. MOST GEOTECHNICAL AND GEOLOGIC FINDINGS ARE PROFESSIONAL OPINIONS Our interpretations of subsurface conditions are based on field observations from widely spaced sampling locations at the site. Site exploration identifies subsurface conditions only at those points where subsurface tests are conducted or samples are taken. GeoEngineers reviewed field and laboratory data and then applied our professional judgment to render an opinion about subsurface conditions throughout the site. Actual subsurface conditions may differ, sometimes significantly, from those indicated in this report. Our report, conclusions and interpretations should not be construed as a warranty of the subsurface conditions. GEOTECHNICAL ENGINEERING REPORT RECOMMENDATIONS ARE NOT FINAL Do not over-rely on the preliminary construction recommendations included in this report. These recommendations an: not final, because they were developed principally from GeoEngineers' professional judgment and opinion. GeoEngineers' recommendations can be finalized only by observing actual subsurface conditions revealed during construction. GeoEngineers cannot assume responsibility or liability for this report's recommendations if we do not perform construction observation. Sufficient monitoring, testing and consultation by GeoEngineers should be provided during construction to confirm that the conditions encountered are consistent with those indicated by the explorations, to provide recommendations for design changes should the conditions revealed during the work differ from those anticipated, and to evaluate whether or not earthwork activities are completed in accordance with our recommendations. Retaining GeoEngineers for construction observation for this project is the most effective method of managing the risks associated with unanticipated conditions. A GEOTECHNICAL l:NGINEERING OR GEOLOGIC REPORT COULD BE SUBJECT TO MISINTERPRETATION Misinterpretation of this report by other design team members can result in costly problems. You could lower that risk by having GeoEngineers confer with appropriate members of the design team after submitting the report. Also retain Geo Engineers to review pertinent elements of the design team's plans and specifications. Contractors can also misinterpret a geotechnical engineering or geologic report. Reduce that risk by having GeoEngineers participate in pre-bid and preconstruction conferences, and by providing construction observation. GIVE CONTRACTORS A COMPLETE REPORT AND GUIDANCE Some owners and design professionals believe they can make contractors liable for unanticipated subsurface conditions by limiting what they provide for bid preparation. To help prevent costly problems, give contractors the complete geotechnical engineering or geologic report, but preface it with a clearly written letter of transmittal. In that letter, advise contractors that the report was not prepared for purposes of bid development and that the report's accuracy is limited; encourage them to confer with GeoEngineers and/or to conduct additional study to obtain the specific types of information they need or prefer. A pre- bid conference can also be valuable. Be sure contractors have sufficient time to perform additional study. File No. 1079/-005-00 December 19, 2008 D-2 GEOENGINEliR~ I I I I I I I I I I I r -I I I I I I I I I I I I I I I I I I I Only then might an owner be in a position to give contractors the best information available, while requiring them to at least share the financial responsibilities stemming from unanticipated conditions. Further, a contingency for unanticipated conditions should be included in your project budget and schedule. CONTRACTORS ARE RESPONSIBLE FOR SITE SAFETY ON THEIR OWN CONSTRUCTION PROJECTS Our geotechnical recommendations are not intended to direct the contractor's procedures, methods, schedule or management of the work site. The contractor is solely responsible for job site safety and for managing construction operations to minimize risks to on-site personnel and to adjacent properties. READ THESE PROVISIONS CLOSELY Some clients, design professionals and contractors may not recognize that the geoscience practices (geotechnical engineering or geology) are far less exact than other engineering and natural science disciplines. This lack of understanding can create unrealistic expectations that could lead to disappointments, claims and disputes. GeoEngineers includes these explanatory "limitations" provisions in our reports to help reduce such risks. Please confer with Geo Engineers if you are unclear how these "Report Limitations and Guidelines for Use" apply to your project or site. GEOTECHNICAL, GEOLOGIC AND ENVIRONMENTAL REPORTS SHOULD NOT BE INTERCHANGED The equipment, techniques and personnel used to perform an environmental study differ significantly from those used to perform a geotechnical or geologic study and vice versa. For that reason, a geotechnical engineering or geologic report does not usually relate any environmental findings, conclusions or recommendations; e.g., about the likelihood of encountering underground storage tanks or regulated contaminants. Similarly, environmental reports are not used to address geotechnical or geologic concerns regarding a specific project. BIOLOGICAL POLLUTANTS GeoEngineers' Scope of Work specifically excludes the investigation, detection, prevention or assessment of the presence of Biological Pollutants. Accordingly, this report does not include any interpretations, recommendations, findings, or conclusions regarding the detecting, assessing, preventing or abating of Biological Pollutants and no conclusions or inferences should be drawn regarding Biological Pollutants, as they may relate to this project. The term "Biological Pollutants" includes, but is not limited to, molds, fungi, spores, bacteria, and viruses, and/or any of their byproducts. If Client desires these specialized services, they should be obtained from a consultant who offers services in this specialized field. File No. 1079/-005-00 December 19, 2008 D-3 GEOENGINEERS _a; I I I I I I I I I I I I I I I I I I I King County Department of Transportation Road Services Division Engineering Services Section King Street Center 201 South Jackson Street Seattle, WA 98104-3856 August 4, 2011 C/9>.. •r 01 Rento Planning o· / 11 IVS/on FEB 1 2 2013 TO: Don Althauser, Managing Engineer, Water and Land Resources Division, Stormwater Services Section FM: Bill Kerschke, Environmental Scientist, Road Services Division, Engineering Services Section ~ Julia Turney, Environmental Engineer, Road Services Division, Enginee~ -O Services Section RE: May Creek Drainage Improvement Project (9A 1205) Post-Construction Erosion Monitoring Plan -Downstream of 148th Avenue SE Introduction This memo was prepared to address comments from the Washington Department of Ecology and the public on the May Creek Drainage Improvement Project. This memo describes the post-construction erosion monitoring plan for the reach of May Creek downstream of 148th Avenue SE. Project components, including in-stream sediment and vegetation removal between mile 4.3 and 4.9 of May Creek, have raised public concern that properties downstream of 148th Avenue SE may be impacted by post-project changes in stream bed and/or bank erosion. Studies already completed by King County Water and Land Resources indicate that the project will not effect downstream erosion (WRLD); however, King County is committed to confirming this assertion post-project. The intent of this memo is to describe an approach for a post-construction monitoring that will evaluate project-related changes in erosion in May Creek between 148th Avenue SE and the Coal Creek Parkway SE. This reach is often referred to as the "canyon reach" of May Creek. Background Studies Studies were completed to evaluate downstream impacts for the proposed May Creek project. A sediment transport study (Anchor 2009) was implemented to analyze the erosion threshold in May Creek between 148th Avenue SE and Coal Creek Parkway SE. This study included selection of a study reach, data collection, analysis, preparation of a HEC-RAS model of the reach, and evaluation of the discharge at which the bed sediment begins to move. According to the sediment mobility evaluation, the threshold of motion occurs between approximately 70 to 350 cubic feet per second (cfs). Don Althauser August 4, 2011 Page 2 A hydraulic and hydrologic modeling analysis (King County 2010) was completed for the project that noted, post-construction, a minimal increase in surface water elevations and water velocities are predicted in the downstream canyon reach. This minimal increase is due primarily to existing hydrologic control points just downstream of the project area (at approximately River Mile 4.2 to 4.3). The hydraulic and hydrologic study concluded that effectively no significant change between existing and proposed conditions at the modeled flood frequency would occur. In addition, at higher flow rates, even less differences between pre-and post conditions would occur. Furthermore, the proposed May Creek Drainage Improvement Project features, including the installation of native plant buffers, removal of in-stream vegetation and sediment, construction of sediment management foatures in Long Marsh Creek, and excavation of alcoves downstream of 148th Avenue SE, are estimated to result in a net reduction in fine sediment and organic material reaching Marsh Creek within the project area. Fine sediment, which currently accumulates in the channel and moves downstream during high-flow events, is anticipated to move downstream at a more constant rate post-construction. Post-Constrll!ction Monitoring Plan King County WLRD proposes to implement a five-year monitoring plan post- construction between 148th A venue SE and Coal Creek Parkway SE to address the concerns of increased post-project erosion in the canyon reach of May Creek. The monitoring effon: will build upon prior and ongoing monitoring efforts implemented during the Sediment Transport Study (Anchor 2009) and proposed monitoring in the May Creek Canyon Reach Draft Monitoring Plan (Anchor 2010). Current Downstream Erosion Monitoring Efforts Anchor Engineering was retained by King County to develop the May Creek Canyon Reach Draft Monitoring Plan (Anchor 2010) for the reach downstream of 148th Avenue SE. In 2010 and 2011, King County WRLD implemented the May Creek Canyon Reach Draft Monitoring Plan to collect baseline data (King County 2011 ). The intent of the May Creek Canyon Reach Draft Monitoring Plan is to gather supplemental data 10 be used to identify and document potential impacts from the upstream project implementation, building upon information gained from the Sediment Transport Study (Anchor 2009). The proposed monitoring from this plan includes installation of a water level sensor, bed pins and bed hooks, and channel profile surveys to document existing conditions that allow for identification of changes to the channel bed. The hydro logic elevations and physical conditions of a stream channel enable the identification of changes in the character of the stream to be monitored. Surveyed physical characteristics of the May Creek channel enabled evaluation of changes in channel cross-sectional geometry and provided information on sediment movement through the reach. The sediment mobility evaluation in the Sediment Transport Study (Anchor 2009) identified a threshold of motion to occur between approximately 70 and 350 cubic feet per second (cfs). Therefore, it was determined that monitoring should occur at events I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Don Althauser August 4, 2011 Page 3 greater than approximately 70 cfs. Detailed data collection and monitoring protocols and descriptions of monitoring sites can be found in the attached May Creek Canyon Reach Draft Monitoring Plan (Anchor 2010) and are summarized below. The monitoring sites and potential monitoring elements at each site are identified in Table l below, which has been included for reference from the attached May Creek Canyon Reach Draft Monitoring Plan (Anchor 20 l 0). The monitoring site locations are shown in Figure I in the attached May Creek Canyon Reach Draft Monitoring Plan (Anchor 2010); however, please note that Figure l in the attached report contains an error, showing Tract A and D transposed. In Figure I of the attached, the right and left bank are referenced looking downstream. Also, please note that since preparation of the May Creek Canyon Reach Draft Monitoring Plan (Anchor 2010), King County's access to Tract A (Broussard property) was revoked by the property owner. In addition, monitoring at Station I in the Sediment Transport Study (Anchor 2009) was discontinued due to braided channel flow conditions and recurring vandalism at the site. Therefore, continued monitoring efforts will occur on only six sites. T bl 1 M ·t a e om onna s· 1tes an d Eff rt 0 s Monitoring Site Monitorin!I Elements Bank Location PT BH BP Riaht Left Parhaniemi/Gambini* X X X X X Tract A (Broussard)** X X X Duffus Right Bank X X Duffus Left Bank X Tract D X X X Cole X X X Stonegate Tract X X X * Referred to as Site 2 m the Sedcment Transport Study (Anchor 2009) ** Proposed monitoring at this site was subsequently cancelled due to access issues. PT = Pressure transducer, BH= Bed hooks, BP = bank pins. Set of Hook/Pins 1 1 3 1 2 2 2 A cross-section survey is to be completed at every site for each transect (bank pins and/or bed hooks). In addition, Gage 37B (Figure 1 in attached May Creek Canyon Reach Draft Monitoring Plan) is to be reconciled due to inconsistencies in the stage flow relationship. Reconciliation of the gage will allow for the development of a long-term, site specific data record that can be used to improve the accuracy of the sediment mobility evaluation and predictions about future channel erosion. The monitoring described in the May Creek Canyon Reach Draft Monitoring Plan (Anchor 2010) will continue until the project is constructed and for five years post- construction. Don Althauser August 4, 2011 Page 4 Additional Proposed Erosion Monitoring Downstream In addition to the above referenced monitoring from the May Creek Canyon Reach Draft Monitoring Plan (Anchor 2010), King County proposes to install scour and fill chains (Harrelson et al. 1994) at each of the six sites (property owner permission dependant) in Table I to monitor sediment movement. These sites provide some baseline cross section and erosion data from past monitoring. Scour chains are steel chains implanted in streambeds to measure erosion and deposition of sediment over a period of time. The scour chains will allow for the evaluation of movement of bed material at threshold storm events (70 cfs) and sediment deposition as waters subside. This information cannot be obtained from cross-section surveys or the other conventional methods already proposed. Recording the amount of scour and fill at the sample locations provides information describing how sediment is moving through the lower system. To measure erosion and deposition, scour chains (Figure I) and metal chains anchored onto metal plates and buried vertically in the channel bed, would be installed in the streambeds at each of the monitoring sites. When sediment is eroded from the streambed during a flood event, the exposed chain falls flat, forming a bend. Sediment deposition that would occur as waters receded, would rebury the chains. The amount of bed erosion is determined by comparing the original length of chain buried to the length left below the bend. The amount of deposition is identified by measuring the depth of sediment above the bend. Two to seven scour chains will be installed at each of the six monitoring sites and their locations documented for future relocation (survey and photograph). Scour chains will be installed in areas where the greatest amount of erosion is anticipated from previous monitoring, thalweg location, and bed erosion. Cross section data will be used to identify the elevation of bed material at each site and the length of each buried chain will be recorded, allowing calculation of changes in bed elevation when the scour chains are monitored over time. After each measured flow event, chains will be excavated to measure erosion and deposition and then straightened and reburied. Procedure for Inserting Scour Chains (from Reclamation 2008) I. Implant chains with colored cork floats. 2. Slip duck bill anchor around the bottom of the inserter. 3. Hold chain as taut as possible. 4. Hold inserter vertical at bed surface. 5. Pound the top of the inserter into the bed/bank with a sledge hammer until the inserter handle is at the water surface, or the chain is sufficiently buried (The anchor should be buried at least 25 cm, or it won't set properly.) 6. Set the anchor by pulling back and forth on the inserter and twisting. 7. Once anchor is set, pull out the inserter using a pipe wrench. I I I I fl I I I I I I I I I I I I I I I I I I I I I I I I I Don Althauser August 4, 2011 Page 5 Pull up on the chain remove any slack. 8. After chain is set, replace any gravel that may have created a hole around the chain; then attach hog ring to the first link that is exposed at the bed surface. 9. Measure the chain length from the hog ring to the end of the chain, and record. 10. Survey the bed surface at the position of the chain using total station. Maximum Erosion and Deposition (sco ur and fill) Calculation Scour: 1) Difference in elevation from the hog ring to the kink, calculated from the number of links (each link was 35 millimeters [mm] long). 2) Difference in elevation calculated from the surveys: elevation at the time of installation minus elevation of kink during measurement. Fill: Elevation of the surface at final measurement minus elevation of the kink. 9 Figure 1 : Schematic of Scour Chain (Lyl e, 1991) and Installation Process (USEPA) Don Althauser August 4, 201 l Page 6 References King County. 2011. May Creek Baseline Monitoring (Preliminary Draft) -Implementing May Creek Canyon Reach Draft Monitoring Plan (Anchor 20 I 0). King County. 2010. Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project. Prepared by Jeff Burkey, King County Department of Natural Resources and Parks, Science Section. Prepared for Stormwater Services Section, Capital Services Unit. December 2010. Available at: http://www.kingcounty.gov/environment/watersheds/ce dar-river-lake-wa/may- creek/hydraulic -hydrologic-analyses.as px Anchor. 2010. May Creek Canyon Reach Draft Monitoring Plan. Prepared by Anchor QEA, LLC for King County Department of Natural Resources and Parks. December 2010. Anchor. 2009. May Creek Sediment Transport Study. Prepared by Anchor QEA, LLC for King County Department of Natural Resources and Parks. June 2009 . Available at: h!!n://www .kingcounty.gov/environment/watersheds/cedar-river-lake- wa/may-creek/sediment-transport-study.aspx Reclamation. 2008. Klamath River Salmon Redd Scour Study, 2007 -2008, Technical Memorandum No. 86-68290-08-02, Technical Service Center, Denver, CO. USDA. 1994. Harrelson, C.C., C.L. Rawlins , and J.P. Potyondy. Stream channel reference sites: An illustrated guide to field technique. General Technical Report RM-245 . Nawa, R., & Frissell, C. 1993 . Measuring Scour and Fill of Gravel Stream beds with Scour Chains and Sliding-Bead Monitors. North American Journal of Fisheries Management, 13 , 634-639. Lisle, Thomas E.; Eads, Rand E. 1991 . Methods to measure sedimentation of spawning gravels. R es. Note PSW-411. Berkeley, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture; 7 p. US EPA, Watershed Assessment of River Stability & Sediment Supply (WARSSS), Field Methods and Procedures, downloaded from http://water.epa.gov/scitech/datait/tools/warsss/method.cfin August 4, 2011. Attac hm ents May Creek Canyon Reach Draft Monitoring Plan (Anchor 2010) I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I MAY CREEK CANYON REACH DRAFT MONITORING PLAN MAY CREEK SEDIMENT TRANSPORT STUDY PHASE 4 Prepared for King County Department of Natural Resources and Parks 201 S. Jackson Street, Suite 600 Seattle, Washington 98104-3856 Prepared by Anchor QEA, LLC 1605 Cornwall Avenue Bellingham, Washington 98225 December 2010 I I I I I I I I I I I I I I I I I I I TABLE OF CONTENTS 1 INTRODUCTION .................................................................................................................. 1 2 DATA COLLECTION METHODS AND PROTOCOLS ....................................................... 2 2.1 Monitoring Events ........................................................................................................... 2 2.2 Equipment ........................................................................................................................ 2 2.3 Monitoring Elements ....................................................................................................... 3 2.3.1 Pressure Transducers .................................................................................................. 3 2.3.2 Cross-Section Survey .................................................................................................. 3 2.3.3 Bed Hooks and Bank Pins .......................................................................................... 4 3 MONITORING SITES ............................................................................................................ 6 3.1 Previously-Established Sites ............................................................................................ 6 3.1.1 May Creek Park (Station 1) ........................................................................................ 6 3.1.2 Gage 37B-Coal Creek Parkway ............................................................................... 7 3.1.3 Parhaniemi Property (Station 2) ................................................................................ 7 3.1.4 Tract A (Station 3) ...................................................................................................... 7 3.2 New Monitoring Sites ...................................................................................................... 8 3.2.1 Duffus Property -Left Bank ...................................................................................... 8 3.2.2 Duffus Property -Right Bank ................................................................................... 8 3.2.3 Tract D ........................................................................................................................ 8 3.2.4 Cole Property .............................................................................................................. 8 3.2.5 Stonegate Tract ........................................................................................................... 9 4 SUMMARY .......................................................................................................................... 10 List of Tables Table 1 Summary of Monitoring Elements ....................................................................... 6 List of Figures Figure 1 Proposed Monitoring Locations May Creek Canyon Reach Monitoring Plan May Creek Sediment Transport Study Phase 4 i December 2010 090159-01 I I I I I I I I I I I I I I I I • I I 1 INTRODUCTION Anchor QEA, LLC (Anchor QEA) and KPFF Consulting Engineers were retained by King County (County) to assist in developing a monitoring plan for the Canyon Reach (Reach) of May Creek downstream of 148th A venue SE. The monitoring effort will gather supplemental data to be used to identify and document potential impacts from upstream project implementation, building upon the prior monitoring effort implemented during Phase I of the project. The following sections of this plan will define elements of the Phase I monitoring effort to be re-implemented, refined, or discontinued. New procedures and elements of the plan will also be described, and new monitoring locations will be identified to build on the data collected in the previous study. The monitoring plan will be implemented by County staff. May Creek Canyon Reach Monitoring Plan May Creek Sediment Transport Study Phase 4 1 December 2010 090159-01 2 DATA COLLECTION METHODS AND PROTOCOLS A data collection and monitoring program was previously developed for the May Creek Sediment Transport Study during Phase I to document baseline conditions and provide data for the sediment mobility analysis. The current scope builds on and refines the methodology performed during Phase I to collect supplemental data. King County personnel will perform monitoring tasks, including completion of monitoring forms and survey. The specific monitoring to be performed at each site is described in Section 3. 2.1 Monitoring E,,ents According to the sediment mobility evaluation during Phase 2, the threshold of motion occurs between approximately 70 and 350 cubic feet per second (cfs). Therefore, each location should be monitored following precipitation events greater than approximately 70 cfs. Because the range of critical discharge is relatively large, one purpose of the site visits is to narrow the range of observed discharges where erosion is observed and no apparent erosion is observed. These data will help to improve the precision of the sediment mobility evaluation. 2.2 Equipment Following is a list of the necessary items for each field visit following initial establishment of monitoring sites: 1. 30 bed hooks ( eye bolts) 2. Three 2-foot re bar stakes, or more following a large flow event 3. Tape measure (30-foot minimum) 4. Sledge hammer 5. Colored flagging 6. Monitoring forms (spreadsheet printouts) 7. Spray paint 8. Waders or boots 9. Gloves May Creek Canyon Reach Monitoring Plan May Creek Sediment Transport Study Phase 4 2 December 2010 090159-01 I I I I I I I I I I I I i I I I I I I I I I I I I I I I I I I I I I I Monitoring Sites 2.3 Monitoring Elements The following sections describe the various forms of data collection methods that may be implemented throughout the site including installation and monitoring. 2.3.1 Pressure Transducers Pressure transducers (piezometers) with internal data loggers are to be installed in the creek channel at the locations specified to collect hourly and daily water surface elevation data. Transducer data shall be collected periodically by County personnel. 2.3.2 Cross-Section Survey Each transect at a monitoring station shall include a left and right bank re bar with cap, placed such that a line between the re bar is perpendicular to the flow of the creek. The rebar caps represent benchmark points along the specific transect; surveyed points will be relative to the left bank re bar cap. The re bar shall be placed outside of the possible extent of erosion or flooding such that there is no risk of its position being compromised. Upon initial installation of the monitoring elements, a cross-section survey shall be completed of each monitoring site. A laser-level and survey rod may be used for the survey to produce a cross-section relative to the left bank re bar cap. This control point should be tied into a known vertical coordinate system, such as North American Vertical Datum (NA VD) 88. All measured distances during the cross-section survey shall be measured from the left bank rebar benchmark to produce a cross-section survey looking downstream. Survey shall be collected across the channel between the left bank to the right bank rebar; if a level and rod is used, a string or tape may be placed between the rebar to ensure a straight, consistent section. Survey points shall be collected at no greater than 1-foot changes in ground elevation, except at near-vertical banks where major grade breaks may be surveyed. Collecting survey at this resolution will allow for detection of minor changes in the channel cross-section. The position of each bed hook shall also be included in the survey and noted in the description. In addition to the channel cross-section, the survey crew shall collect a point in the lowest part ofthe channel bed at approximately 50 and 100 feet upstream and downstream of the May Creek Canyon Reach Monitoring Plan May Creek Sediment Transport Study Phase 4 3 December 2010 090159-01 Monitoring Sites rebar. These points will be used to represent the local gradient at the monitoring site, and provide preliminary indication of bedform modification within the reach. The cross-section and gradient survey shall be repeated per the process above when one or more of the following conditions apply: o When significant erosion or deposition at the monitoring location is evident from dislodgement o:r covering of bank pins or bed hooks o Following a flood event of 2-year or greater recurrence interval, approximately 200 cfs o At the end of the monitoring period 2.3.3 Bed Hooks and Bank Pins Each monitoring location shall include either bed hooks, bank pins, or both to monitor erosion or deposition of the bed and erosion of the banks. The location and condition of bed hooks and bank pins will be documented during each site visit. Bed hooks consist of eye bolts driven into the streambed at 2-foot intervals along a transect across the channel. Colored flagging shall be attached to each eye bolt to improve visibility during monitoring. Bed hooks are recommended in locations suitable to monitoring bed movement. Bank pins shall be distributed within the study area in locations where bank erosion is likely to occur prior to bed movement and shall consist of 2-foot lengths of re bar driven flush into the bank along a transect. At least four lengths of re bar should be installed for each location specified for bank pins. Bank pins should be installed in locations where the greatest amount of erosion can be expected; therefore, it is important that the locations are refined in the field by personnel familiar with site conditions. After each critical flow event, monitoring locations shall be investigated for the presence or absence of each of the bed hooks (eye bolts) or exposure of the bank pins (rebar). Any change to these features shall be measured and documented using the monitoring forms. The protocol for each monitoring event is provided below. Note: Bed hooks are included at one site only, see Section 3. 1.3. 1. Assess the site for obvious storm effects or potential vandalism and note in the site conditions sections of the monitoring form. May Creek Canyon Reach .N.Ionitonflg Plan May Creek Sediment Transport Study Phase 4 4 December 2010 090159-01 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Monitoring Sites 2. Attach the measuring tape to the left bank benchmark (rebar with cap), confirm the presence or absence of all bed hooks, and document the findings in the monitoring forms. a. If bed hooks are present, mark "P" under the correct column in the form. If any bed hooks are partially exposed, measure the distance of exposure and record on the monitoring form. Use a sledge hammer to drive the bed hook flush with the channel bottom. b. If bed hooks are absent, mark "A" under the correct column in the form. Note if it appears that the bed hook has been eroded away or buried by deposition. c. Replace any bed hooks that were missing and attach flagging to each. 1. Using the attached measuring tape, measure out the required replacement distance necessary to replace the missing bed hooks. 11. Bed hooks should be flush with the channel bottom and securely placed using a sledge hammer, as necessary. d. If any bed hooks were absent, a repeat survey of the transect should be performed per Section 2.3.2. 3. Evaluate bank pins, measure the length of exposure, and document in the monitoring forms. a. If bank pins are flush to the bank, record "O" in the length of exposure column in the monitoring form. b. If bank pins are exposed, measure the length of exposure and record in the corresponding column in the monitoring form. c. Re-mark each bank pin using spray paint for easy location during the next monitoring visit. d. If re bar is missing, replace by measuring down from re bar cap to correct elevation (given on the monitoring form), reinstall into bank, and re-mark. e. If any bank pins were absent or the re bar exposed such that the original position of the pin is offset, a repeat survey of the transect should be performed per Section 2.3.2. 4. Repeat steps 1 through 3 for each monitoring site. May Creek Canyon Reach Monitoring Plan May Creek Sediment Transport Study Phase 4 5 December 2010 090159-01 Monitoring Sites 3 MONITORING SITES Two previously-established and five new locations are proposed for the current Canyon Reach monitoring effort. In addition, we recommend that Gage 37B be reconciled. Table 1 includes a summary of which monitoring elements should be included at each site, excluding Gage 37B. A cross-section survey should be completed at every site for each transect (bank pins and/or bed hooks). The details at each site are discussed in the following sections. Monitoring Sit1, Location Parhaniemi Tract A Duffus Right Bank Duffus Left Bank Tract D Cole Stonegate Tract Notes: PT= pressure transducer BH = bed hooks BP= bank pins Table 1 Summary of Monitoring Elements Monitoring Elements Bank Sets of PT BH BP Right Left Hooks/Pins • • • • • 1 • • • 1 • • 3 • 1 • • • 2 • • • 2 • • • 2 The approximate location of each site is shown in the accompanying Figure 1. However, the final position of each monitoring transect should be determined in the field by personnel familiar with site condi1:ions in order to collect the most reliable data. 3.1 Previously-Established Sites 3.1.1 May Creek Park (Station 1) Station 1 is located downstream of the Coal Creek Parkway crossing within May Creek Park. Monitoring at Station 1 will not be continued for the purposes of the current effort. May Creek Canyon Reach Monitoring Plan May Creek Sediment Transport Study Phase 4 6 December 2010 090159-01 I I I I I I I I I I I I i I I I I I I I I I I I I I I I I I Monitoring Sites 3.1.2 Gage 378 -Coal Creek Parkway Gage 37B is located at Coal Creek Parkway crossing between Stations 1 and 2. The purpose of this gage was to establish a long-term flow record that could be used collectively with the data from the Phase 1 monitoring effort to perform the sediment mobility study. However, during the data collection period, perturbations observed in the flow record indicated that the stage flow relationship for the gage was not a constant and the gage records for 37B could not be used reliably for the study. Therefore, it is recommended that flow monitoring at Gage 37B be continued and the gage reconciled such that the data may be used reliably in the future. This may involve re-installation of the gage outside of the influence of channel obstructions, or other means. These data will allow for the development of a long term, site specific data record that can be used to improve the accuracy of the sediment mobility evaluation and predictions about future channel bank erosion. 3.1.3 Parhaniemi Property (Station 2} Monitoring at Station 2 will be continued per the recommendations of the Phase 1 monitoring plan, including continued data logging using a pressure transducer and re- establishment of bed hooks and bank pins. Bed hooks and bank pins should be installed as a transect across the channel along the same cross-section as previously used during Phase 1 monitoring. This site is well suited for evaluating bed movement in the creek and will continue to be useful in monitoring changes to the bed elevation through the canyon reach. Continued monitoring will allow for refinement of the threshold of erosion-discharge relationship developed for the Phase 2 sediment transport study. 3.1.4 Tract A (Station 3} This location was formerly referred to as Station 3 during the previous phases of the Project. Pressure transducer and bed hooks data are no longer recommended for collection at this site. Because of the dynamic nature of the location (documented channel migration in previous phase of work) this site is well suited for monitoring bank erosion. Bank pins will be installed along the right bank in the same cross-section as used during Phase 1 monitoring. The left and right bank re bar benchmarks should be placed well into the floodplain to avoid compromising the position of the benchmark due to bank erosion. May Creek Canyon Reach Moniton'ng Plan May Creek Sediment Transport Study Phase 4 7 December 2010 090159-01 Monitoring Sites 3.2 New Monitoring Sites 3.2.1 Duffus Pro 1perty -Left Bank One section of bank pins shall be implemented at this site along the left bank, upstream of the resistant clay bank near Station 25+00. At least four bank pins should be installed at an even spacing between the top and bottom of the bank. Active erosion has not been observed at this site; however, the landowner has expressed concerns about lateral migration to the east. Therefore, the left and right bank rebar benchmarks should be placed well into the floodplain to avoid compromising the position of the benchmarks due to erosion or floodwaters. 3.2.2 Duffus Pro1,erty -Right Bank Three sections of bank pins shall be implemented at this site along the right bank at the actively eroding cut bank, downstream of the existing retaining wall. At least four bank pins should be installed at an even spacing between the top and bottom of the bank. This site has a large potential for future erosion based on field observations. The right bank rebar benchmark should be placed well outside of the expected extent of erosion to avoid compromising the position of the benchmark. 3.2.3 TractD Bank pins will be installed at this site to monitor potential bank erosion. Bank pins shall be installed along the left and right banks within the Tract A properties, just downstream of the Tabacek parcel where the stream is confined by stone walls. Bank pins should be installed in the locations where the greatest amount of erosion is expected in two locations (one on each bank); the locations do not necessarily have to be along the same transect. Bank pins should not be installed where stone armoring is present. 3.2.4 Cole Property Bank pins will be installed at this site to monitor potential bank erosion. Bank pins shall be installed along the left and right banks within the Cole property downstream of the Lyons Avenue bridge crossing. Bank pins should be installed in the locations where the greatest amount of erosion is expected in two locations (one on each bank); the locations do not May Creek Canyon Reach Monitoring Plan May Creek Sediment Transport Study Phase 4 8 December 2010 090159-01 I I I I I I I I I I I I I I I I I I I I I I I Monitoring Sites necessarily have to be along the same transect. Bank pins should not be installed where bridge reinforcements or abutments are present. 3.2.5 Stonegate Tract Bank pins will be installed at this site to monitor potential bank erosion. Bank pins shall be installed along the left and right banks within the Stonegate Property, just upstream of the Bonwell property. Bank pins should be installed in the locations where the greatest amount of erosion is expected in two locations (one on each bank); the locations do not necessarily have to be along the same transect. May Creek Canyon Reach Monitoring Plan May Creek Sediment Transport Study Phase 4 9 December 2010 090159-01 4 SUMMARY The recommended monitoring plan will accomplish three purposes: 1. Reconcile Gage 37B to provide a long-term hydrologic record for the site. 2. Collect additional data to refine the sediment mobility evaluation. 3. Collect information specific to monitoring bank erosion in the upper canyon reach. May Creek Canyon Reach Monitoring Plan May Creek Sediment Transport Study Phase 4 JO December 2010 090159-01 I I I I I --.. ------- r' ,, '' - ~f-, ..... ,;-.,. ~-. ~ .. ' '"",l-,,./ ·-~· -·~· -- 0 z w l:l w _, ., '' Cl C C 0 "" ~ en 0 .E ' 0 0 ~ + ",;,., .. 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V, "' :, <1) u .!!! ~ "' 'tJ V, ~ C 0 0 u.. ·;:; "' V, u <1) 2 -0 <( z -- I I I I I I I I I I I I I I I I I I I BASELINE STREAM CONDITIONS MA YI CREEK DRAINAGE IMPROVEMENT CIP#9A1205 Revised December 2, 2010 ti King County Prepared by: Erick Thompson Environmental Scientist I II and Kerry Bauman Environmental Scientist III Department of Transportation Roads Services Division Environmental Unit 201 South Jackson Street, Suite 200 Seattle, Washington 98104 City of Renton Planning Division FEB 1 2 Wl3 I I I I I I I I I I I I I I I I I Table of Contents I Summary .................................................................................................................. 1-3 2 Introduction .............................................................................................................. 2-5 3 Methods .................................................................................................................... 3-7 3.1 Literature Review ............................................................................................. 3-7 3.2 Field Methods .................................................................................................. 3-7 4 Existing Conditions .................................................................................................. 4-9 4.1 General Site Survey ......................................................................................... 4-9 4.2 Stream Habitat ............................................................................................... 4-13 4.3 Substrate ......................................................................................................... 4-23 4.4 Large Woody Debris and Pool Quality .......................................................... 4-24 4.5 Riparian and In-Stream Vegetation ............................................................... 4-25 4.6 Bank Condition .............................................................................................. 4-27 4. 7 Fish Habitat and Use ...................................................................................... 4-28 5 Discussion .............................................................................................................. 5-29 6 References .............................................................................................................. 6-30 List of Figures Figure 1. Vicinity Map .................................................................................................... 2-6 Figure 2. May Creek Drainage Basin .......................................................................... .4-l 0 Figure 3. Stream Features ............................................................................................. 4-12 Figure 4. Habitat in Sequence in the study area ........................................................... .4-l 5 Figure 5. Habitat Unit Proportions, as surface area ...................................................... 4-17 Figure 6. Reach One Habitat.. ....................................................................................... 4-18 Figure 7. Reach Two Habitat ........................................................................................ 4-20 Figure 8. Reach Three Habitat ...................................................................................... 4-21 Figure 9. Reach Four Habitat. ....................................................................................... 4-22 Figure 10. Stream Substrate .......................................................................................... 4-24 Figure 11. Overhanging Plants ..................................................................................... 4-25 Figure 12. In-Stream Plants .......................................................................................... 4-26 Figure 13. Proportion of bank types ............................................................................. 4-27 List of Tables Table I. Habitat Survey Summary ................................................................................ 4-16 Table 2. Pool Characteristics ........................................................................................ 4-17 Table 3. Substrate .......................................................................................................... 4-23 Table 4. Detailed streambed substrate .......................................................................... 4-24 Appendix A: Photos Appendix B: Stream Survey Data May Creek Drainage Improvement Baseline Stream Conditions Page 1-2 1 Summary King County Department of Natural Resources and Parks proposes to remove sediment and in-channel plants that obstruct water flow from portions of May Creek in May Valley to increase channel capacity and reduce flood duration in adjacent pastures. The stream in this area is nearly flat and flows through large wetlands, many of which are currently used as pastures for horses. Historically, May Valley provided floodwater storage for tributaries draining the upper May Creek basin. Limited capacity to transport sediment through the flat valley allowed sediment to accumulate. Land owners periodically cleared the stream of sediment and in-channel plants until about the 1940's (King County 1995). Since then, development in the upper watershed to the north and south of May Valley has increased stormwater run-off, leading to an increase in the frequency and duration, but not magnitude, of flooding in May Valley (King County 1995). Some infilling of the May Creek channel by fine sediment mobilized during flooding has probably contributed to increased flooding in the valley. Chronic winter flooding of some properties in May Valley limits the use of these properties for pasture and grazing livestock, mostly horses. We evaluated stream baseline conditions on about 2,800 feet of May Creek, beginning about 328 feet downstream of 1481h Ave SE, near river mile (RM) 4.35, and ending near RM 4.87. In the proposed project area, May Creek flows through a flat, formerly ditched channel in an oversized valley formed by glacial meltwater (King County 1995). The valley is bordered on the north by Cougar and Squak mountains, which are bedrock, and on the south by the East Renton Plateau, which is formed by glacial deposits. The flat May Valley reach of May Creek stores stormwater and sediment, slowly releasing both to a higher gradient ravine downstream of the study reach. Slow water and abundant cover from overhanging vegetation in the study reach provide rearing and refuge habitat for coho salmon, cutthroat trout, and rainbow/steelhead trout. These fishes also use the mainstem creek as a migration corridor to spawning and rearing habitat in tributaries such as the North Fork, Cabbage Creek, Country Creek, and Tributary 0291A. Stormwater and sediment storage in the valley also help maintain spawning and rearing habitat for salmon in reaches of May Creek located downstream of May Valley, primarily from RM 0.2 to RM 3.9, which is identified as a "Locally Significant Resource Area" in the May Creek Current and Future Conditions Report (King County 1995). Five species of salmon are found in May Creek downstream of May Valley: chinook, sockeye, and coho salmon, and cutthroat and rainbow/steelhead trout (King County 1995). Puget Sound Chinook salmon and steelhead are listed as threatened under the Federal Endangered Species Act. If the proposed project requires a federal permit or has federal funding, then endangered species act consultation for Chinook salmon and steelhead will be necessary. May Creek Drainage Improvement Baseline Stream Conditions Page 1-3 I I I I I I I I I I I I I I I I I I I I I Key Points: I. May Valley was historically an area of floodwater and sediment storage as the nearly flat stream braided through extensive wetlands. The channel was ditched between 1910 and 1936 for agriculture (King County 1995). The ditched channel filled with sediment and was dredged in the I 940's to reduce flooding, and refilled with sediment again by the 1960's (King County 1995). Heavy truck farming was taking place in the valley during this time, and agricultural fields were plowed right up to the top of the stream banks (King County 1995). 2. Current sediment sources to May Creek in May Valley have not been clearly identified. The May Creek Erosion Stabilization Draft Report (Anchor QEA, LLC 2010) only addresses erosion downstream of May Valley. It is unclear if flows in the flat valley reach have enough power to transport sediment the nearly two miles from upstream sources to the project area, and large sediment plumes from tributaries were not observed during site visits. Gravel transported to May Creek from Long Marsh Creek creates one of the few potential spawning areas within the project area. Erosion is present in May Canyon, a ravine located about 0.7 mile downstream of the project area (King County 1995, Anchor QEA 2010). The May Creek Hydraulic Analysis (King County 2010) evaluated whether sediment removal in the valley would worsen erosion in the ravine. The analysis showed that there is no substantial difference between the rate of erosion that occurs in the ravine under existing conditions and the erosion that would occur under any of the sediment removal alternatives. 3. Areas of the valley that are designated as open space, where flooding does not threaten homes or pastures, and where an intact woody riparian corridor exists, provide pockets of refuge for rearing and migrating fish. If left intact, these areas may provide refuge for fish affected by sediment removal elsewhere in the valley. 4. The proposed project ("Ineffective Flow Project #1 ") is one of four conceptual ineffective flow projects described in the May Creek Drainage and Restoration Plan (Geoengineers 2008). The combined length of the four conceptual projects is about 2.26 miles of May Creek in May Valley, which is 75% of the valley length and 32% of May Creek's entire length. A total of33 projects are identified in the drainage and restoration plan (Geoengineers 2008). These projects include the four ineffective flow projects (direct channel modifications) described above, as well as 29 indirect channel modifications such as culvert and bridge replacements, and wetland and steam enhancements (Geoengineers 2008). May Creek Drainage Improvement Baseline Stream Conditions Page 1-4 King County Department of Natural Resources and Parks, Water and Land Resources Division (KC DNRP) proposes to remove sediment and in-channel plants from portions of May Creek within May Valley to increase channel conveyance capacity and reduce flood duration in adjacent pastures. A total of four "ineffective flow" channel clearing projects are described in the May Creek Drainage and Restoration Plan (GeoEngineers 2008). The four projects together total about 2.26 miles, which is about 75% of the total length of May Creek in May Valley, and about 32% of the total seven- mile length of May Creek. Thirty-three projects are identified in the drainage and restoration plan (Geoengineers 2008). These projects include the four ineffective flow projects (direct channel modifications) described above, as well as 29 indirect channel modifications such as culvert and bridge replacements, and wetland and steam enhancements. We studied existing conditions on about 2,800 feet of May Creek, beginning about 328 feet downstream of 148 1 h Ave SE, near river mile (RM) 4.35, and ending near RM 4.87, and roughly corresponding to the area of May Creek identified in "Ineffective Flow Project #I" (GeoEngineers 2008, Figure I). Our study evaluates the suitability of the stream as fish habitat, and physical processes affecting the stream, stream channel, and stream inhabitants. Included in the study is a review of existing literature and information about May Creek, a qualitative general site survey which evaluates the physical and biological characteristics of the channel and the surrounding areas, and quantitative measurements of in-stream fish habitat, riparian and in-stream plants, and bank conditions. May Creek Drainage Improvement Baseline Stream Conditions Page 2-5 i I ll I I I I I I I I I I l\tlay Creek Channel Restoration Project Project V icinity e StudyA rea o Mile Mar kers Stream Incorporated Areas Cougar Mounta in Wildland Park N + March 2010 tQ King County o 95 190 760 IIIIIIIIC====lllllllllllll[====::J Fee 380 570 Th•i'*rrnllioft ~ed onlNI fNph• b_.. compltd ti,- ~ Ceun~sutfffom i1wnetyotsowo. uMI W sub)M:tto "'---~ CGUn• ""*• no ,.-tMfltllors orw,naitiM:, upreu o, ~.•to ..cqlqtf. oor,."*-'-s. t:lmelnen. o, ,W. 1Dht.St4'tuchWenndon. 1h11 OOo.,rNntis not lntendedilf .... • ,UUl'W"f' p,ocluol. t0"8 Coun.Sftal not N bb•1cw •"l's»ent1•L•peoul. lldltct. atd.,.._ o, .,.-.,.MW daf"O• lnd_,..I, but noC ltmlld t, IGl't f.-.rlUlf Of kst Pfotls , .... ng *cimh weormlswt dl'l•l•rrnmon OOMJined one-ii: map Nf/solloofW.maporlNOttnaioft onthlJ l'l'llp isp,ohl:llttd -plbf-po"'*tlon <I 1<11,g Counly. Figure 1 <*-1:1>5-D_~~~ .,'Cq_ I I I I I I I I I I I I I I I I I I 3 Methods 3. 1 Literature Review We reviewed the following information to identify natural drainage system features and provide background information prior to field visits: 0 May Creek Current and Future Conditions Report, March 1995. King County Surface Water Management Division; 0 May Creek Basin Action Plan, April 2001. King County Department of Natural Resources, Water and Land Resources Division; 0 May Creek Drainage and Restoration Plan, December 2008. GeoEngineers; 0 May Creek Erosion Stabilization Draft Report, May Creek Sediment Transport Study Phase 3, January 2010. Anchor QEA, LLC; 0 May Creek Hydraulic and Hydrologic Analysis. 2010. King County Department of Natural Resources, Water and Land Resources Division; 0 Particle Size Evaluation of May Creek Water Channel Soils, Job Number IB 1205, Task MTR. 2010. King County Department of Transportation, Materials Lab, Renton, WA. 0 Washington Department of Fisheries. 1975. A Catalogue of Streams and Salmon Utilization. Volume I. Olympia, Washington; 0 Snyder et al. 1973. Soil Survey of King County Area, Washington. Soil Conservation Service; ~ King County Sensitive Areas Map Folio. 1990. Maps 4 (Duwamish) and 9 (Issaquah). 3.2 Field Methods We visited the study area on three occasions in 20 I 0: twice in the winter when flows were high, and once during summer low flow. We conducted reconnaissance-level evaluations during the winter visits, and a detailed in-stream, bank, and riparian study during the summer visit. On February I, 20 IO King County Roads Environmental Unit Senior Ecologists Erick Thompson and Kerry Bauman walked about 2,800 feet of May Creek, beginning about 328 feet downstream of 148 1 h Ave SE, near RM 4.35, and proceeding upstream to the May Creek Drainage Improvement Baseline Stream Conditions Page 3-7 "red barn" at about RM 4.87(Figure I). We walked May Creek to visually characterize channel morphology, bank condition, substrate, in-stream aquatic habitat, large wood, and riparian plant communities and land-uses. We measured wetted channel width and depth in representative locations, but high water prevented identification ofbankful channel width and depth. We used field observations to characterize the present condition of the stream channel, including its suitability as fish habitat and its apparent conveyance capacity for water and sediment. We also noted any fish, other aquatic organisms, and wildlife or wildlife signs we noticed during the survey, and took photographs to provide a visual record (Appendix A). On August 16 and 17, 2010 we assessed in-stream habitat using several combined methods including Timber-Fish-Wildlife (Pleus et. al. 1999) and Fish Habitat Relations (FHR), as modified by King County from the USDA Forest Service Stream Habitat Classification and Inventory Procedures for Northern California (McCain et al. 1990). We identified and measured habitat units, collected information on residual pool depth (maximum pool depth minus tail-out depth), pool-forming factors, pool quality (Platts et al. 1987) and large woody debris (LWD). We used the Timber-Fish-Wildlife definition ofLWD (wood that lies or protrudes within the vertical axis ofbankful width, Pleus et al. 1999). We recorded LWD diameter and length, variety (coniferous or deciduous), stability (pinned, buried, attached rootwad, free to go), and whether the LWD was forming a pool or trapping sediment. For each habitat unit we also identified bank type (armored, sloped, vertical, and undercut) and estimated the percent and type of overhanging, instream rooted, and "floating mats" of vegetation. We used a handheld GPS unit to survey broad-scale riparian plant communities (forest, shrub, or grassland) and bank vegetation types (tree, shrub, or grass dominated). May Creek Drainage Improvement Baseline Stream Conditions Page 3-8 I I I I I I I I I I I I I bit l!!I I I I I I I I I I I I I • I I I I I I 4 !Existing Conditions 4.1 General Site Survey The general site survey is qualitative, based on information obtained through review of existing background information and observations made during site visits. Results of the general site survey should not be viewed as a systematic, quantitative evaluation of the features described. 4.1.1 Existing Drainage System May Creek is about seven miles long, with about 19 miles of tributary streams, draining about l 4 square miles in eastern King County (Figure 2, King County l 995). Three headwater creeks join at the top of May Valley to form the main channel, which flows through the valley and a narrow, erosive ravine before flowing into Lake Washington (Figure 2). The bedrock foothills of Cougar Mountain, Squak Mountain, and Newcastle Hills form the uplands north of May Valley, and a gently rolling plateau of glacial deposits (East Renton Plateau) forms the uplands south of May Valley (King County 1995). The valley itself was carved by glacial meltwater, and is underlain by 200 to 500 feet of unconsolidated glacial sediments (King County 1995). Tributaries descending through the glacial deposits of the plateau to the south and across the steep bluffs of the ravine are highly erosive and contribute large amounts of sediment to May Creek, whereas tributaries descending from the bedrock-underlain foothills to the north of May Valley are less erosive (King County 1995). May Valley was historically an area of sediment deposition and flood storage, and the stream channel braided through extensive wetlands. The stream was put in a ditched single-strand channel so the surrounding floodplain could be used for agriculture. Storm and surface water storage in May Valley is important for controlling erosion in the ravine, which is experiencing erosion in both the mainstem and tributaries (King County 2001, Anchor QEA 2010). May Creek Drainage Improvement Baseline Stream Conditions Page 4-9 May Creek Channel Restoration Project Stream Features • Study Area o River Mile /"'/ Streets /"'/ Streams Incorporated Areas Cougar Mountain Wildland Park N -(- March 2010 tQ King County 0 480 ---~====----1r::==::::::i Feet 60 120 240 360 The information in duded on this map has been compled by King County staff from a variety of sources and is subjed to change wlhout notice . King Co unty makes no representations or warranties, express or impled, as to accuracy, completeness, timeiness, or rigtrts to the use of such inform ation. This document is not intended for use as a survey produd. King County shall not be liable fo r any general, specia l, indirect, inadental, or consequential damages induding, but not imited to, lost revenues or lost profit s resulting from the use or misuse of the information contained on this map. hly sale of this map or informati on on this map is prohibited except by written permission of King County. Figure 3 PD V,t04'UIC'0'9'6110t•• ttllllqtcl:'dill\1:1>.S-DNPP ~ C••• P',utlall,t lJl•tJGUa,GC I I I I I I I I I I I I I I I I I I I 4.1.2 Riparian Land Use and Vegetation Small berry and horse farms, and open space are the primary remaining land-uses in May Valley. Wetlands that have been converted to horse pastures border both sides of the stream in the project reach, except for the area downstream of l 48'h Ave SE, which is open- space associated with the Stonegate development (Figure 3). Reed canarygrass (Phalaris arundinaceae) is pervasive. Stands of willow (Salix spp.) and red alder (A/nus rubra) in the downstream portion of the project reach greatly improve the stream channel from a habitat and natural channel morphology perspective. These woody plants stabilize stream banks, provide shade, food, and hiding cover, and affect in-stream habitat by providing hard points that create a mixture of slow-water and fast water areas. The channel in the upstream portion of the project reach, which lacks woody plants and is almost exclusively vegetated with reed canarygrass, is more uniform and has filled in with up to 18 inches of sediment, making the surrounding area prone to flooding. Sources of this sediment are unclear. It may be deposited by tributaries and stored in the valley, or it may be eroded from surrounding horse pastures, deposited in the stream channel, and stored in the valley. Horse pastures in the vicinity of the filled-in channel sections slope toward the stream and are muddy throughout much of the year (Appendix A, Photos 42, 44, 56, 59, 64, 67). 4.1.3 Adjacent Wetlands Wetlands are present along May Creek through most of the project area. Many wetlands have been converted to horse pastures and will be described in more detail under separate cover. Dominant vegetation is reed canarygrass. We saw both resident and migratory waterfowl using the open water wetland on the south side of May Creek, including mallards (Anas p/atyrhynchos), American widgeon (A. Americana), and wood ducks (Aix sponsa). 4.1.4 Animal Habitat and Use May Creek and associated wetlands provide habitat for a wide variety of animals. Although we did not see terrestrial wildlife during site visits, we can assume that the following species use habitats within the study area: deer, bobcat, coyote, raccoon, moles, voles, and mice, as well as waterfowl and songbirds. We saw two buck rubs on willows adjacent to the stream; one rub was downstream of the 148 1h Ave SE Bridge, near RM 4.4, and one rub was upstream of the bridge, near RM 4.5. We saw both resident and migratory waterfowl in the open water wetland on the south side of May Creek near RM 4.75, including mallards, American widgeon, and wood ducks. Although we did not see them, salamanders, frogs, and crayfish are probably present in aquatic habitats within the proposed project area. May Creek Drainage Improvement Baseline Stream Conditions Page 4-11 I I I I I I I I I I I I I I I I I I 4.1.5 Riparian Soils, Bank Stability, and Channel Morphology From our vantage on the streambanks in February, it looked as though the project reach of May Creek has two primary channel forms, which are influenced by the riparian plant community. In areas where willows are present and in contact with stream flow, the channel form appears to be mostly forced pool riffle, with pools being forced by scour against channel-spanning willow branches or willow stems within the active channel. In areas where riparian vegetation consists of reed canarygrass or trees high on the banks, the channel form appears to be plane-bed. Both channel forms derive from past excavations and ditching for agriculture and sediment deposition. The channel gradient is flat throughout. We confirmed the two general channel forms described above when we made more detailed observations in August. However, water flow patterns appear to simplify when water elevations drop below the level needed to contact willow branches spanning the channel. The mix of slow water and fast water we observed during higher flows in February was thus simplified to uniform slow-water glides, or shallow pools too small to identify individually, during the habitat survey conducted in August. In February the water was too high for us to see the banks in most locations. Where banks were visible, stability looked good. A more detailed assessment of bank conditions performed in August confirmed that most banks are stable. Results of the more detailed survey are presented in Section 4.6. The King County Area Soils Survey maps soils in May Valley as mostly Alderwood and Bellingham soils. Alderwood soils formed in glacial deposits, and Bellingham soils formed in alluvium found mostly in depressions in glacial deposits (Snyder et al. 1973). We did not sample soil during site visits, but soils observed in soil pits during the wetland delineation will be described under separate cover. 4.2 Stream Habitat We could not wade most of the stream reach during the February I, 20 l O survey because the water was too deep. Most observations and limited measurements were made while standing on the banks. The August 16 and 17, 2010 in-stream habitat survey was conducted during low flow so we could quantify habitat and bank conditions. Given the highly variable nature of stream flows, the low flow stage is considered the most repeatable and thus the standard for comparisons over time. We divided the surveyed portion of May Creek into four reaches based mostly on the nature of the riparian corridor (Figure 3). In-stream habitat in the surveyed reach of May Creek is influenced by riparian plant communities. Aquatic habitat is more complex in places where the riparian corridor has woody plants, such as willows, actively engaged with the stream channel and May Creek Drainage Improvement Baseline Stream Conditions Page 4-13 connected floodplain. Overhanging or rooted willow branches or stems provide cover and hard points necessary for bedform complexity, producing both turbulent and non- turbulent flow areas, backwaters and riffles, and shade and nutrients during the summer (Appendix A, photos 9, 12, 14, 23, 25). Areas with no woody riparian plants are more uniform and tend to have accumulations of fine sediments in the channel (Appendix A, Photos4,5, 10, JI, 13,47,50to58,60,61). Habitat units as we encountered them in sequence along the study area during the August 16 and 17, 2010 survey are presented in Figure 4 and Appendix B. May Creek within the project limits was dominated by slow water glides (Table I, Figure 5). Pools made up about one quarter of the surface area in Reaches One and Two, about ten percent of the area in Reach 3, and about 13 percent of the area over the entire surveyed reach; no pools were present in Reach Four (Figure 5). All of the pools were lateral scour pools except one mid-channel pool in Reach One (Table 2). Fast water was limited to a single low-gradient riffle at the 148'h Ave SE bridge, and a couple of pool tail-outs in Reach One (Figure 4). Many of the areas inventoried as glide during the low-flow stream survey had both turbulent and non-turbulent flow during the February stream reconnaissance. This is most apparent in Reach Two, which has a relatively wide, mature, willow-dominated riparian corridor. Dense willow branches cross the stream channel throughout this reach, functioning like a debris complex and creating numerous backwater areas during higher flows. This reach is well-connected with its floodplain, and some floodplain terracing is present, which also increases habitat complexity during higher flows. The wider forested riparian area has shaded out reed canarygrass. In areas where reed canarygrass dominates, such as Reach Four, the channel tends to be deeper and has thicker accumulations of fine sediment (Appendix B). May Creek Drainage Improvement Baseline Stream Conditions Page 4-14 I I I I I I I I I I I I -----11111 ---!Bl ------- 5001 f Slow Water Fast Water 4001 I 111 Reach 1 Reach 2 Reach 3 Reach 4 r N E ';;;' 300 I!! < " " ~ ::, U) f Flow 200 100 QllllJ[J ,11 Li WI I I I I l I I I I I I Q ~J ol~IJn[U.~.~.~ Q Q ~ q q q O Q Q Q Q Q Q O Q ~ q Q q ~ Q Q Q O Q Q O ~ Q Q g q O q O O Q Q Q Q O Q Q Q Q Q && ~~~&&&&&&&&& ~&~$&&&&&&&~&&~~&~&&&&&&&&&&&& Habitat Units in Sequence - Figure 4. Habitat in Sequence in the study area. Dotted area is fast water, solid area is slow water. GLD= glide, T= tail-out, LSP= lateral scour pool, MCP= mid-channel pool, LGR=low gradient riffle. May Creek Channel Restoration, CIP #9Al205. liiiil I Table I. Habitat Survey Summary. Summary of habitat, bank condition, and riparian and instream plants measured during the August 2010 habitat survey. LB=left bank, RB= right bank, water flows from Reach 4 to Reach I. May Creek Channel Restoration, CIP #9Al205. Reach 1 Reach 2 Reach 3 HABITAT Average Wetted Width (m) 3.9 3.5 3.5 Average Wetted Depth (m) 0.3 0.3 0.4 Bankful Width ( m )" 5.2 3 14 NA Bankful Depth ( m )" 1.5' 0.7 0.8 Percent Glide 74 68 90 Percent Pool 25 23 JO Percent Riffle 2 9 0 Ave Residual Pool Depth (m) 0.6 0.5 0.3 Average Pool Ouality4 4.2 3.7 3.0 Number of Pools 5 3 1 NumberofLWD 0 0 2 PLANTS LB RB LB RB LB RB Percent Grass 59 64 25 26 39 71 Percent Willow/Grass 6 7 42 45 0 0 Percent Willow 7 4 14 22 0 0 Percent Rooted Grass/Reeds 0 0 7 Percent Floating Mats 7 4 2 Area Floating Mats (m') 30.8 14.4 12.0 BANKS LB RB LB RB LB RB Percent Sloped Bank 9 18 53 45 71 75 Percent Undercut Bank 12 12 21 15 3 14 Percent Vertical Bank 69 65 26 39 19 10 Percent Armored Bank 10 6 0 0 7 0 ' Averaged over the enttre proJect area, not an average of reach averages 2Measured in representative locations, not in every habitat unit. 3grass-dominated area Reach 4 Entire' 3.9 3.7 0.5 0.34 NA NA 1.3 NA 100 85 0 13 0 2 NA NA 3.9 0 9 0 2 LB RB LB RB 100 96 67 72 0 0 8 9 0 0 22 16 56 21 8 6 51 85.4 LB RB LB RB 51 49 46 47 0 0 8 9 49 49 43 43 0 0 4 1 4 Platts et al. (1987). The Pool Quality Index is a scale ofone to five, with five been the best pool quality. May Creek Drainage Improvement Baseline Stream Conditions Page 4-16 I I I I I I I I I I I I I I I I I I I I I I I I 'I I I I I I 100 DG\ide cu DPool ~ < Q) 80 D Riffle u ~ 74 68 :I 60 Cl) 90 85 iij 10( -0 I-40 ... 0 --C: -Q) u 20 23 .. Q) 25 c.. -13 ~ m:9m 10 0 ' ' Reach 1 Reach 2 Reach 3 Reach4 Entire Figure 5. Habitat Unit Proportions, as surface area (m2). Dotted area is fast water, solid area is slow water. Water flows from Reach 4 to Reach I. May Creek Channel Restoration, CIP #9A1205. Table 2. Pool Characteristics. PQI is a pool quality rating system developed by Platts et al. (1987) where pools are given a score of I to 5 (highest quality), LWD=large woody debris. May Creek Channel Restoration, CIP #9A1205. Pool Characteristics Total Pools 9 Pool Types Number Percent Mid-channel Pool 1 11 Lateral Scour Pool 8 88 Average residual pool depth (m) 0.5 Average PQI rating 3.9 Average pool length (m) 14 Average pool area (m 2) 52.3 Average pool volume (m 3) 20.2 Percent slow water pools 100 Percent fast water pools 0 Percent pools associated with L WO 22 The four surveyed reaches are described in greater detail below. Reach One: Stonegate property line (about RM 4.33) to 14s'h Ave SE bridge (RM 4.46). Reach one consisted of74 percent glide, 25 percent pool, and two percent riffle (Figure 5). Habitat units in sequence are presented in Figure 6. The effect of riparian plant communities is pronounced in Reach One. Most of the reach has a mature willow- May Creek Drainage Improvement Baseline Stream Conditions Page 4-l 7 dominated riparian corridor, with reed canarygrass dominating the understory. Wetted channel width is 32 to 49 feet. Substrate consists mostly of fine-grained sand and silt, but some small gravels ( one to two-inch size) are exposed in fast water areas. As described above, overhanging and rooted willow branches and stems provide cover and hard points to create complex in-stream aquatic habitat. Water is clear and cold. The mixture of slow water and fast water habitats and abundant cover provide good rearing habitat for coho salmon (Oncorhynchus kisutch) and trout (0. clarki and 0. mykiss). We also saw a buck rub on a willow in this reach (Appendix A, Photo 8). The channel is well connected with its floodplain, and the reach provides flood storage. 180 - 160 140 Reach 1 120 Flow i .. 100 2! < .. u 80 '2 - :, U) -60 - 40 20 0 --- n I n ' oll GLD GLD T LSP LSP LSP GLD GLD GLD GLD GLD GLD GLD GLD GLD T MCP GLD LSP Habitat Units In Sequence Figure 6. Reach One Habitat. Habitat as it occurs in sequence in Reach One. Dotted area is fast water, solid area is slow water. GLD=glide, T= tail-out, LSP= lateral scour pool, MCP= mid-channel pool. May Creek Channel Restoration, CIP #9A1205. Interspersed among the willow-dominated areas are a few stretches of stream with no woody riparian plants (Figure 3). The riparian corridor in these areas is dominated by reed canarygrass. Flow is uniformly slow and deep, with deep accumulations of fine sediment. Wetted width is about 13 feet, wetted depth is about 4.9 feet, and fine sediment accumulation is about 1.6 feet. These stretches of stream are less structurally complex than the willow-dominated areas, and reed canarygrass is the primary influence on in-stream fish habitat. Although reed canarygrass-dominated slow water, uniform, channels provide limited habitat for most species of salmonids, these areas do provide rearing habitat for coho salmon fry because the grass slows the water current and provides hiding cover and shade. May Creek Drainage Improvement Baseline Stream Conditions Page 4-18 I I I I I I I I I I I 0 I I I I I I I I I I I I I I I I I I The channel becomes wider and shallower, and accumulations of fine sediment disappear near the entrance to the forested riparian corridor (Figure 3). Wetted channel width is about 19 feet; wetted depth is about 1.6 feet, and one to three-inch clean, loose gravels dominate the substrate, with some cobbles present along the channel edges. Red alder, willows, Indian plum (Oemleria cerasiformis), sword fem (Polystichum munitum), and reed canarygrass are dominant riparian vegetation. The forested reach may provide spawning habitat for coho salmon and trout, as well as rearing habitat. We observed Greenes Creek during a site visit on March I, 2010, when the May Creek stream level was substantially lower than on February I, 2010 (Appendix A, Photo 6). Greenes Creek flows from the East Renton Plateau toward the left (south) bank of May Creek at about RM 4.4 (Figure 3). The creek did not enter May Creek at the time of the site visit, but instead dissipated and infiltrated in the adjacent wetland (Appendix A, photo 7). We saw no sediment deposition from Greenes Creek in either the wetland or in May Creek. Reach Two: 148 1h Ave SE Bridge (about RM 4.46) upstream to fence line (about RM 4.55). Reach Two consisted of 68 percent glide, 23 percent pool, and nine percent riffle (Figure 5). Habitat units in sequence are presented in Figure 7. Reach Two has a relatively wide, mature willow-dominated riparian corridor. In-stream habitat is mixed riffle and glides or pools. Substrate is dominated by accumulations of fine sediments. This reach is well-connected with its floodplain. We observed evidence of recent overbank flooding and flood storage in the riparian corridor. We saw a second buck rub on a willow in this reach (Appendix A, Photo 26). May Creek Drainage Improvement Baseline Stream Conditions Page 4-19 180 160 Slow Water Reach 2 140 Fast Water 120 Flow Ng .. 100 e <( .. " 80 ~ ~ U) 60 40 20 0 ~ LGR GLD GLD GLD GLD GLD GLD GLD LSP GLD GLD LSP LSP Habitat Units In Sequence Figure 7. Reach Two Habitat. Habitat as it occurs in sequence in Reach Two. Dotted area is fast water, solid area is slow water. LGR=low gradient riffle, GLD=glide, LSP=lateral scour pool. May Creek Channel Restoration, CIP #9Al205. Reach Three: Fenceline (about RM 4.55) upstream to end of woody riparian corridor (about RM 4.7). Reach Three consisted of90 percent glide and 10 percent pool (Figure 5). Habitat units in sequence are presented in Figure 8. Willows are absent and the mature red alder-dominated riparian corridor is much narrower, about IO feet wide, in Reach Three. Reed canarygrass dominates the understory, and horse pastures are present on both sides of the stream. The wetted channel width is about 21 feet and the wetted depth is about 3.0 feet, substrate is mostly fine sediment. The horse pasture on the right bank is about three to four feet above the February 20 lO water surface, suggesting that the channel in this reach is currently large enough to transport higher flows than those present during our survey (Appendix A, Photo 44). The increased channel capacity in this area is likely a result of sediment that was removed by King County in 2002 as part of a channel obstruction removal pilot project. Long Marsh Creek enters May Creek on the right bank at about RM 4.62 (Figure 3). This tributary is a source of gravels to May Creek and there are about 65 feet of stream with spawning-sized gravels around the stream confluence (Appendix A, Photos 30, 32, 37, 38). May Creek Drainage Improvement Baseline Stream Conditions Page 4-20 I I I I I I I I 0 I I I I I I I I I I I I I I I I I I 280 - 240 Reach 3 ' S!ow Water Fast Water 200 Flow "E ';; 160 I!! <( .. " ~ 120 . :, -U) - 80 ~ --40 - 0 GLD LSP GLD GLD GLD GLD GLD Habitat Units in Sequence Figure 8. Reach Three Habitat. Habitat as it occurs in sequence in Reach Three. Solid area is slow water. GLD= glide, LSP=lateral scour pool. May Creek Channel Restoration, CIP #9Al205. Reach Four. End of woody riparian corridor (about RM 4.7) to red barn (about RM 4.9). Reach Four consisted of LOO percent glide (Figure 5). Habitat units in sequence are presented in Figure 9. The riparian corridor in Reach Four consists almost entirely of reed canarygrass. The channel is straight, narrow, and deep, and has less capacity to contain water than the other reaches. Wetted channel width is about 13 feet, wetted depth is about 4.3 feet, and fine sediment deposited on the channel bottom is one to 1.6 feet deep. May Creek Drainage Improvement Baseline Stream Conditions Page 4-21 550 500 450 - 400 Ng 350 .. 300 I!! < G) 250 u ~ :, "' 200 150 100 50 0 GLD GLD l-_....J Slow Water Fast Water GLD GLD Reach4 GLD Habitat Units In Sequence Flow GLD GLD Figure 9. Reach Four Habitat .. Habitat as it occurs in sequence in Reach Four. Solid area is slow water. GLD= glide. May Creek Channel Restoration, CIP #9AI205. During the February I, 20 IO site visit, pastures on both banks of the stream were flooded. It was not clear whether the flooding was entirely a result of overbank flow from May Creek, or a combination of overbank flow and high groundwater level. Water from the flooded pasture on the left bank was flowing into May Creek at the time of our survey, and overbank flow from May Creek seemed to be flooding the pasture on the right bank (Appendix A, Photo 48). It was difficult for us to find the May Creek channel in some of the flooded areas, and we could not find the confluence oflndian Meadows Creek, so we were unable to evaluate sediment inputs from this tributary. It also looked as though erosion from muddy horse pastures upslope of May Creek may contribute sediment to the stream. During a follow-up site visit on March I, 20 IO we were able to find the Indian Meadows Creek confluence with May Creek (Appendix A, Photos 63 to 68). This stream drains Grand Ridge on the north side of May Valley and is piped and channelized along a private driveway before entering the right bank of May Creek at about RM 4.88 (Figure 3). Substrate in the flat, unpiped portions of this stream consisted of spawning-sized gravels that are routinely removed from the channel prior to reaching May Creek (Appendix A, Photos 64, 65, 67). A small deposit of fine sediment from Indian Meadows Creek is present in May Creek at the confluence, but the sediment does not appear to have much effect on the channel's capacity to contain flow. May Creek Drainage Improvement Baseline Stream Conditions Page 4-22 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 4.3 Substrate Stream substrate consists almost entirely of mineral sediments, most of which are fine-grained silts and sands (Table 3, Figure IO). We observed small pockets of small to large gravels at the downstream end of the surveyed area, in Reach One, and at the Long Marsh Creek alluvial fan in Reach Two. Sediment was deep within much of the stream, especially in Reach Four, which lacks woody plants and is almost exclusively vegetated with reed canarygrass. The channel cross-section is also more uniform in Reach Four, and on average 1.5 feet of sediment had accumulated in the channel there (Appendix B). Table 3. Substrate. Dominant and subdominant substrate size classes observed on the stream bed (surface area estimates). May Creek Channel Restoration, CIP# 9AI205. Size Class Dominant (%) Subdominant (%) 1: Sand, silt, clay, muck 94 91 (<0.25" or <0.8 cm) 2: Small gravel (0.25"-1" 2 1 or 0.9-2.5cm) 3: Large gravel (> 1 "-3" or 4 7 2.6-7.5cm) 4: (>3"-6" or 7.6-15cm) 0 1 5: (>6"-12" or 15.1-30cm) 0 0 6: (>12"-40" or 30.1 cm-0 0 1ml 7: (>40" or >1m) 0 0 8: (Bedrock) 0 0 May Creek bottom sediments were sampled by the King County Department of Transportation Materials Laboratory (King County, May 20 IO and October 2010). In the area of 1461h Avenue SE, the channel bottom is composed of sands and gravels to well- graded gravel. Larger gravel, cobbles and occasional boulders are also present. In the relatively flat and low gradient portions of May Valley in the area of l48'h Avenue SE the hard channel is composed of silty-sand and sandy-silt. At the confluence with Long Marsh Creek the hard channel bottom is composed of well graded gravel. A variable layer of soft muck is present within the stream channel behind constrictions in the channel. The muck was sampled 25 feet upstream of a private bridge at RM 4.6. A modified Loss on Ignition analysis (LOI) was performed and the sediment organic content was about 28 percent. The exact source of this high organic content is unknown; however, the tributary stream channels within the project area do not contain the same muck material and the most likely source are pastures, agricultural fields, and grass and tree litter within and above the project limits. Sediment sample results are presented in Table 4. May Creek Drainage Improvement Baseline Stream Conditions Page 4-23 Large Gravel 4% Small Gravel 2% "--'-T-- Sand, silt, clay, muck 94% Figure I 0. Stream Substrate. Proportion of dominant stream substrate sampled during the habitat survey. May Creek Channel Restoration, CIP #9Al205. Table 4. Detailed streambed substrate, analyzed by King County Materials Lab in May and October 2010. May Creek Channel Restoration, CIP #9A1205 Denth Location 0 to 3 inches 3 to 6 inches Orirnnics Reach 1: -75 ft downstream of silty sand 148 1h brid2:e Reach 2: -100 ft upstream of 148'" sandy silt bridge Reach 3: Long Marsh Creek well graded confluence gravel Reach 4:-25 ft uostream of RM 4.6 sandy silt siltv sand 28% 4.4 Large Woody Debris and Pool Quality Nine pools were inventoried in the habitat survey (Table 2). Six of the pools were formed from scour against willows. Of the remaining three pools, one was formed by scour against the 148 1h Ave SE abutment, one was bed-formed, and one appeared to be the result of prior sediment removal. Pool quality varied little within the surveyed reach, ranging from a score of three to a score of five on the PQI rating system (Table 2, Platts et al. 1987). May Creek Drainage Improvement Baseline Stream Conditions Page 4-24 [i I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I We found no debris jams and few individual large pieces of wood within the banks of the surveyed reach of May Creek (Table 1). We inventoried only two pieces of L WO within the surveyed stream. However, in many places willow branches extend over the active channel and are the principal cause in the formation of six of the nine pools we surveyed. 4.5 Riparian and In-Stream Vegetation Woody and herbaceous plants rooted in the banks had branches and fronds hanging over the active stream channel along much of the surveyed reach (Figure 11 ). Over 80 percent of both streambanks had either reed canarygrass or willows hanging over the channel. Both willows and reed canarygrass were present in Reaches One and Two, but only reed canarygrass was present in Reaches Three and Four (Figure 11 ). 100 -~ D Grass D Grass/Willow DWillow ~ .s:. 80 -~ 1f ... en I 14 >--"- C: 7 -~ 17 11 Cl) 7 ~ .J 6 -· 22 --- tel 60 ~-... 0 -0 I-96 .... 42 0 40 ... ~ 71 C: 64 64 Cl) 59 45 62 I:! -Cl) 20 39 a. 25 0 ll° LB I RB LB I LB I RB LB I RB LB I RB RB Reach 1 Reach2 Reach3 Reach4 Entire Figure 11. Overhanging Plants. Proportion of stream length with plants overhanging the channel. If bar does not total 100%>, then remainder is percent with no overhanging plants. For example, 72% of the length of the left bank in Reach I has overhanging plants (59% reed canarygrass, 6% both grass and willow, and 7% willow only, so 28% of the bank has no overhanging vegetation). LB= left bank, RB= right bank, grass= reed canarygrass, water flow is from Reach 4 to Reach I. May Creek Channel Restoration, CIP #9Al205. Overhanging plants provide cover for fish rearing and seeking refuge along the streambanks. Streams with good riparian cover have high inputs of terrestrial insects because the insects live on the plants and fall into the stream, providing food for fish. Leaves falling into the stream provide a source of nutrients, especially nitrogen, needed for properly functioning aquatic foodwebs. Roots of overhanging plants stabilize soil and May Creek Drainage Improvement Baseline Stream Conditions Page 4-25 prevent bank erosion. Riparian plants also shade the water and help prevent temperatures from rising on sunny days. The water temperature on August 16, 20 IO was 59 Fahrenheit, while the ambient air temperature was 80 to 85 Fahrenheit, illustrating the cooling effect of riparian plants. We defined instream vegetation as rooted plants within the active channel, and mats of plants floating on the water surface; willow branches overhanging the channel were not quantified, and plants rooted on the bank and overhanging the channel are presented in Figure 11. Nearly three-quarters of the surveyed reach consisted of open channel (Figure 12). Open channel did not have plants rooted in the channel, nor mats of plants floating in the channel, but plants rooted on the bank and hanging over the channel were present along both banks for much of this area. About twenty-one percent of the remaining channel had reed canarygrass rooted in the wetted channel. Most of this rooted reed canarygrass was in Reach Four, where 56 percent of the channel had rooted grass; no grass was rooted in the channel in Reaches One and Two (Figure 12). All of the study reaches had a small proportion (less than I 0%) of their surface area covered with floating mats of plants (Figure 12, Table 2). Rooted and floating mats of reed canrygrass and bur-reed (Sparganium angustifolium) provide cover for juvenile salmonids rearing in the stream. 100 -o Rooted in Channel ,, 80 QI - -Cl o Floating Mats 0 C 0 :i:i 0:: ca 56 -o 60 .s::. --u.. Cl- C ca QI I!! 40 ...J < ni ~ -0 21 0 ... I-0 20 [1 ::,!:! 7 7 8 0 4 n!, 0 CJ I --, Reach 1 Reach2 Reach 3 Reach4 Entire Figure 12. In-Stream Plants. Proportions of rooted plants and floating plant mats. If bar for rooted plants does not total I 00%, then remainder is percent with no rooted plants. For example, 7% of the length of Reach 3 has rooted plants in the stream channel, so 93% of the stream channel has no rooted plants, and 2% of the stream has plant mats floating in the channel so 98% of the channel has no floating plant mats. Water flows from Reach 4 to Reach I. Plants rooted in the bank and hanging over the channel may also have been present along both banks for most of this area. May Creek Channel Restoration, CIP #9Al205. May Creek Drainage Improvement Baseline Stream Conditions Page 4-26 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I We measured a total of about 129 square yards (yd2) of floating mats of reed canarygrass and bur-reed in the about 4,096 yd2 of surveyed stream channel (Table 2). Over half of these floating mats (61 rd2) were in Reach Four; Reach One had 37 yd2 of floating mats, Reach Two had 17 yd , and Reach Three had 14 yd 2• 4.6 Bank Condition Most of the banks in the surveyed portion of May Creek were vertical or sloped (Figure 13). Some banks were undercut in Reaches One, Two, and Three, and some bank armoring was present in Reaches One and Three (Figure 13). Left and Right banks were similar throughout the surveyed reach. All banks appeared to be stable. The erosion of streambanks, whether natural of from human causes, can deliver sediment to a stream, impairing water quality and fish habitat. Streams in forested or undeveloped land often have more stable flows and less sediment than streams in cultivated or developed watersheds (Lines et al. 1979). Artificially straightened channels may be prone to bank erosion (Harvey et al. 1985). Alonso and Combs ( 1990) have shown that a straightened and deepened channel had higher banks and increased bank failure. Dense stands of reed canarygrass on the banks of May Creek in May Valley may help control erosion rates because the dense masses of roots hold soil. Undercut banks typically provide better rearing habitat for fish and other aquatic species than vertical or sloped banks. However, the large amount of overhanging vegetation throughout the study area compensates for the less desirable bank types, so they do not limit rearing or cover opportunities for fish. 100 .t: -g1 80 a, ..J .fl 60 0 I--o 40 -C: a, ~ 20 a, 0.. 10 9 69 18 65 53 26 21 45 39 15 71 19 75 10 1 51 49 9 9 RB 12 12 o+--~L~B--r-'-RB0 ~~L~B-i-RBTLB-i-RBTLB Reach 1 Reach 2 Reach 3 Reach 4 46 3 8 LB oAnnored oSloped 4 7 a Vertical o Undercut 3 9 RB Entire Figure 13. Proportion of bank types. LB=left bank, RB=right bank, water flows from Reach 4 to Reach I. May Creek Channel Restoration, CIP #9A1205. May Creek Drainage Improvement Baseline Stream Conditions Page 4-27 4. 7 Fish Habitat and Use May Creek historically was an important salmon stream in the Lake Washington Basin (WDF 1975). The stream supported five species of salmonids: Chinook ( Oncorhyncus Tschawytscha ), sockeye ( 0. nerka ), and coho ( 0. kisutch) salmon, and rainbow/steelhead ( 0. mykiss) and cutthroat ( 0. clarki) trout (King County 1995). Salmon still use the stream and its tributaries even though their numbers have decreased (King County 1995). Chinook and sockeye salmon are found in the lower reaches of May Creek but they most likely do not travel upstream as far as May Valley (King County 1995). Coho salmon and rainbow/steelhead and cutthroat trout rear in May Valley and use it as a travel corridor to upstream spawning habitat in the North Fork, Cabbage and Country Creeks, and Tributary 0291A (King County 1995). Although we did not conduct a formal census of fish in the surveyed reach of May Creek, we observed many schools of salmonids during the August habitat survey (Appendix B). Most schools were about 10-30 individual juvenile fish, and appeared to have both coho salmon and trout. Stormwater stored in May Valley helps maintain spawning and rearing habitat downstream. Floodwaters stored in the valley are released slowly and are thus less likely to scour redds in spawning beds located downstream. Slow release of stormwater from the valley also probably decreases the potential erosion of ravine walls from storm flows. May Creek is located in Watershed Resource Inventory Area (WRIA) 8: Lake Washington Basin. It is a King County Critical Areas Ordinance Type F (fish present) stream, with 165-feet regulatory buffers. Under City of Renton Critical Area Code, May Creek is considered a Class 2 stream (salmonid bearing) requiring a JOO-foot buffer. Puget Sound Chinook salmon and steelhead are listed as threatened under the Federal Endangered Species Act. May Creek Drainage Improvement Baseline Stream Conditions Page 4-28 I I I I I I I 11 I I I I I I I n I I I I I I I I I I I I I I I I I I 5 Discussion May Valley historically was an area of floodwater and sediment storage. The nearly flat stream braided through extensive wetlands. The channel was ditched between 1910 and 1936 for agriculture (King County 1995). The ditched channel filled with sediment and was dredged in the I 940's to reduce flooding, and refilled with sediment again by the I 960's (King County 1995). Heavy truck farming was taking place in the valley during this time, and agricultural fields were plowed right up to the top of the stream banks (King County 1995). Sediment sources to May Creek in May Valley have not been clearly identified. The May Creek Erosion Stabilization Draft Report (Anchor QEA, LLC 2010) only addresses erosion downstream of May Valley. The flat valley reach may not have enough power to transport sediment nearly two miles from upstream sources to the project area, and large sediment plumes from tributaries were not observed during site visits. Gravel transported to May Creek from Long Marsh Creek creates one of the few potential spawning areas within the project area. Gravels in Indian Meadows Creek that are removed from the channel before they reach May Creek could provide additional spawning habitat. While erosion in the ravine is an ongoing problem, the May Creek Hydraulic and Hydrologic Study (King County 2010a), which evaluated several alternatives for sediment removal in the valley, shows that there is no substantial difference in the erosion that occurs in the ravine under existing conditions and erosion that would occur under any of the proposed sediment removal alternatives. If sediment removal is proposed in areas of the valley that are designated as open space, where flooding does not threaten homes or pastures, and where an intact woody riparian corridor provides better fish habitat, mitigation would likely be required to offset the negative affects that the sediment removal would have on fish habitat. These areas may provide pockets of refuge for rearing and migrating fish, and may provide such refuge for fish affected by sediment removal in the valley. The proposed project ("Ineffective Flow Project #I") is one of four conceptual ineffective flow projects described in the May Creek Drainage and Restoration plan (Geoengineers 2008). The combined length of the four conceptual projects is about 2.26 miles of May Creek in May Valley, which is 75% of the valley length and 32% of May Creek's entire length. A total of33 projects are identified in the drainage and restoration plan (Geoengineers 2008). These projects include the four ineffective flow projects (direct channel modifications) described above, as well as 29 indirect channel modifications such as culvert and bridge replacements, and wetland and steam enhancements. May Creek Drainage Improvement Baseline Stream Conditions Page 5-29 6 IRefeireD11ces Alonso, C. V. and S. T. Combs. 1990. Streambank Erosion Due to Bed Degradation. A Model Concept, Trans. ASAE, 33: 1239-1248. Anchor QEA, LLC. 2110. May Creek Erosion Stabilization Draft Report May Creek Sediment Transport Study Phase 3. Prepared for King County Department of Natural Resources. GeoEngineers. 2008. May Creek Drainage and Restoration Plan, King County Washington. For King County Water and land Resources Division and Mid- Sound Fisheries Enhancement Group. Harvey, M. D., C. C. Watson, and S. A. Schumm. 1985. Gully Erosion. U.S. Bureau of Land Reclamation Technical Note 366. King County 1990. Sensitive Areas Map Folio. King County. 1995. May Creek Current and Future Conditions Report. King County. 2001. Final Adopted May Creek Basin Action Plan. King County. 20 !Oa. May Creek Hydraulic and Hydro logic Study (Draft). King County. 20 I Ob. Particle Size Evaluation of May Creek Water Channel Soils, Job Number 181205, Task MTR. King County Department of Transportation, Materials Lab, Renton, WA. Lines, I.L. Jr., Carlson, and R.A. Corthell. 1979. Repairing Flood-Damaged Streams in the Pacific Northwest. Pp. 195-200 in: Johnson and McCormick ( 1979). Washington, D.C. Snyder, D.E., P.S. Gale, and R.F. Pringle. United States Department of Agriculture, Soil Conservation Service. 1973. Soil Survey, King County Area, Washington, Sheet Number 5. Washington Department of Fisheries. 1975. A Catalogue of Streams and Salmon Utilization. Volume I. Olympia, Washington. May Creek Drainage Improvement Baseline Stream Conditions Page 6-30 I I I I [I I I I I I I I I I I I I I I I I I I I I I I I I I .1 I I Appendix A. May Creek Channel Restoration photograph log. Photo perspective is looking upstream unless otherwise noted. Left bank is on the le ft side when facing downstream. Photo 1. Entrance to forest at downstream end of survey; perspective is looking downstream. Photo 2. Cobbles in forested area. Photo 3. Perspective is looking downstream. Photo 4. No woody riparian plants. Photo 5. Photo 6. Greenes Creek. Photo 7. Greenes Creek. No surface flow to May Creek but greener grass probably marks subsurface route. Photo 8. Buck rub on willow. Photo 9. Photo 10. Perspective is looking downstream. Photo 11. Photo 12. Willows provide cover and in-stream structure . I I I I I I I I I I I I I I I I I I I I I I I I I Photo 13 . Photo 16. Newly planted spruce on left bank open space property. I I I I I Photo 14 . Photo 17. I I I I I Photo 15 . Photo 18. Ponded water downstrea m of I 148 th Ave SE bridge. I I Photo 19. 148th Ave SE bridge. Photo 20. 148 1h Ave SE. Photo 21. Looking downstream under 1481h Ave SE bridge. Photo 22. Upstream of 148 th Ave SE bridge. Photo 23. Photo 24. I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Photo 25. Photo 26. Another buck rub on willows . Photo 27. Photo 28. Photo 29 . Photo 30. Confluence of Long Marsh Creek. Photo 31. Footbridge over May Creek near Long Marsh Creek. Photo 32 . Looking upstream at Long Marsh Creek confluence. Gravels at confluence. Photo 33. Photo 34. Photo 35 . Photo 36 . I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Photo 3 7. Long Marsh Creek, looking up the channel from May Creek. Photo 38. Looking down May Creek from Long Marsh Creek. Photo 39 . Narrow alder riparian corridor upstream of Long Marsh Creek confluence . Photo 40. Right bank armor. Photo 41 . Photo 42 . Pasture on left bank. Photo 43 . View of right bank. Photo 44. Horse in right bank pasture. Photo 45. Flooded left bank pasture. Photo 46. End of woody riparian corridor. Photo 47. Photo 48. Flooded left bank pasture flowing into May Creek. I I I I I I I I I I ' I I ! I I I I I I I I I I I I I I I I I I I I I I I I I I Photo 49 . Flooding adjacent to May Creek. Photo 50 . Looking upstream toward Red Barn. Photo 51. Looking downstream. Photo 52. Flooding along both banks of May Creek. Photo 53. Photo 54. Flooded pasture near Red Barn. Photo 55. Photo 56. May Creek channel near Red Barn. Photo 57 . Photo 58. Looking downstream from near Red Barn. Photo 59. Muddy pasture on left bank. Photo 60. I I I I I I 'I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Photo 61. Photo 62. Red Barn driveway bridge across May Creek, looking south. 2/1/10. Photo 63. Looking toward May Creek on 3/1/10. Indian Meadows Creek is in ditch . Photo 64. Indian Meadows Creek culvert outlet. Excavated gravels are piled on banks. Photo 65. Indian Meadows Creek culvert outlet. Photo 66. Indian Meadows Creek looking toward May Creek. All gravels are deposited in this reach. Photo 67 . Indian Meadows Creek, looking upstream from May Creek. All gravels are deposited in short reach indicated by arrow. Stream substrate is fines below lower culvert. Photo 68 . Confluence of Indian Meadows Creek with May Creek, 3/1/10. Minimal sediment deposition at confluence: May Creek is more than a meter (3 ft) deep. I I I I I I I I I I I I I I I I I I I I I I Appendix B: May Creek Habitat Survey Summary Su,vey Date: August 16 & 17, 2010 Staff: Thompson/Bauman/Clark I AU measurements are metric Reference Habitat Unit Mean Average Maximum Residual Unit Unit LWD Distance Type length width Depth Depth Pool Depth area (m 1) Volume(m") PQI • I Reach 1 Begin/Downstream end 1 0 GLD 9 4.5 0.18 40.50 7.29 2 9 GLD 11 3.5 0.35 38.50 13.48 3 20 T 2 3 0.1 6.00 0.60 Scour against overhanging wfllows formed pool 4 22 LSP 5 3 0.3 0.53 0.43 15.00 4.50 4 •• Scour against overhanging w/1/ows formed pool 5 27 LSP 8.5 4.2 0.3 0.55 0.45 35.70 10.71 4 Scour against overhanging wlllows formed pool 6 35.5 LSP 5.5 4.5 0.35 0.6 0.45 24.75 8.66 4 7 41 GLG 7 3.5 0.2 24.50 4.90 I 8 48 GLD 1.8 3.3 0.18 5.94 1.07 9 49.8 GLD 57 3 1 171.00 171.00 10 106.8 GLD 10 3.5 0.4 35.00 14.00 11 116.8 GLD 18 2.6 0.45 46.80 21.06 I 12 134.8 GLD 9 4.3 0.2 38.70 7.74 13 143.8 GLD 8 3.5 0.38 28.00 10.64 14 151.8 GLD 17 3.9 0.5 66.30 33.15 15 168.8 GLD 18 4.3 0.3 77.40 23.22 I 16 186.8 T 2.6 3.4 0.19 8.84 1.68 Possibly Historic Dredged Pool 17 189.4 MCP 13 6.5 0.5 1.06 0.87 84.50 42.25 5 18 202.4 GLD 5.5 3.5 0.16 19.25 3.08 148th AVE S.E. Bridge I Scour along I abutment formed pool 19 207.9 LSP 7 5.5 0.45 0.75 0.59 38.50 17.33 4 Reach 2 20 214.9 LGR 14 4.5 0.2 63.00 12.60 21 228.9 GLD 10 2 0.3 20.00 6.00 22 238.9 GLD 24 3.6 0.3 86.40 25.92 I 23 262.9 GLD 28.5 3 0.2 85.50 17.10 24 291.4 GLD 6.5 2.2 0.55 14.30 7.87 25 297.9 GLD 5.6 2.5 0.2 14.00 2.80 26 303.5 GLD 3.5 3.2 0.55 11.20 6.16 I 27 307 GLD 46 3.7 0.2 170.20 34.04 Scour against overhanging w/1/ows formed pool 28 353 LSP 17.5 4 0.45 0.72 0.62 70.00 31.50 4 29 370.5 GLD 6.2 3.5 0.3 21.70 6.51 30 376.7 GLD 14 5 0.16 70.00 11.20 I Bank formed pool 31 390.7 LSP 10 3.5 0.25 0.54 0.36 35.00 8.75 3 Scour around wf/low 32 400.7 LSP 15 4.2 0.4 0.75 0.63 63.00 25.20 4 Reach 3 33 415.7 GLD 26 4.2 0.35 109.20 38.22 I Scour against bank and roots creat pool 34 441.7 LSP 19 3.5 0.25 0.5 0.3 66.50 16.63 3 Longmarsh Creek Alluvial Fan 35 460.7 GLD 12 3.2 0.28 38.40 10.75 36 472.7 GLD 61 4.5 0.5 274.50 137.25 37 533.7 GLD 17 2.8 0.55 47.60 26.18 I 38 550.7 GLD 16 3.3 0.3 52.80 15.84 39 566.7 GLD 30 3.3 0.5 99.00 49.50 Reach 4 40 596.7 GLD 160 3.3 0.6 528.00 316.80 41 756.7 GLD 36 7 0.3 252.00 75.60 I 42 792.7 GLD 23 3.5 0.45 80.50 36.23 43 815.7 GLD 17 3.8 0.4 64.60 25.84 44 832.7 GLD 18 3.2 0.55 57.60 31.68 45 850.7 GLD 22 3 0.4 66.00 26.40 46 872.7 GLD 48 3.3 0.6 158.40 95.04 I End I Upstream End at Red Barn Bridge I Indian Meadow Creek Alluvial Fan 920.7 I Page B-1 I Appendix B: May Creek Habitat Survey Summary Survey Date: August 16 & 17, 2010 Staff: Thompson/Bauman/Clark All measurements are metric ......... ........ LB Ovemanging V~ RB Owftlanolng V~ LB Bani! TJPI' RBBankT~ -·-Dillt.,rw;:,e ,,.. u.,....,.. ,,,,_ L""!llh (ml ....... l.9ngth (m) ,,.. (ml ,,,. (ml %R-Floatlng (m2) Ruch 1 s.g/nlDownslnYm end 1 0 GLD 9 100%RCG 9.0 100% RCG 9.0 Sloped 9 Sloped 9 2 9 GLD 11 100% RCG 11.0 100% RCG 11.0 Vertical 11 Vertical 11 3 20 T 2 100% RCG 2.0 Scour llpl/1$1 ~llfl ..mows fonned 100% RCG 2.0 Vertical 2 Vertical 2 -4 22 LSP 5 100% RCG 5.0 Scour 1r,11/mf ovemllnglng wmows fwmed 100%RCG 5.0 Vertical 5 Vertical 5 2.3 pool 5 27 LSP 8.5 100% RCG and Willow 8.5 Scour against OVWN11(11no wiJJows formed 100% RCG and Willow 8.5 Undercut (.Sm) 8.5 Undercut (.3m) 8.5 -6 35.5 LSP 5.5 No~ 0.0 Nooe 0.0 S~ped 5.5 Vertical 5.5 7 41 GLG 7 None 0.0 None 0.0 Vertical 7 Sloped 7 8 48 GLD 1.8 90% RCG and Willow 1.6 90% RCG and Willow 1.6 Sloped 1.8 Vertical 1.8 4 9 49.8 GLD 57 100%RCG 57.0 100% RCG 57.0 Vertical 57 Vertical 57 18 10 106.8 GLD 10 S0%W~low 5.0 50% RCG 5.0 Vertical 10 Vertical 10 11 116.8 GLD 18 20% RCG and Willow 3.6 75% RCG 13.5 Vertical 18 Vertical 18 12 134.8 GLD 9 100% RCG 9.0 20% RCG and Willow 1.8 Vertical 9 Sloped 9 13 143.8 GLD 8 50% RCG 4.0 50% RCG 4.0 Vertical 8 Vertical 8 14 151.8 GLD 17 100%RCG 17.0 100% RCG 17.0 Undercut (.Sm) 17 Undertcut (.5 m) 17 2 15 168.B GLD 18 50% Willow 9.0 S0%Wdlow 9.0 Vertical 18 Vertical 18 16 186.8 T 2.6 30% WiDow 0.8 100% RCG and Willow 2.6 Vertical 2.6 Vertical 2.6 Po$slbly Historic DredgtHI Pool 17 189.4 MCP 13 100% RCG 13.0 100% RCG 13.0 Sloped 13 Sloped 13 4.5 18 202.4 GLD 5.5 Bridge 5.5 Bridge 5.5 Arrno,ed 5.5 Annorad 5.5 14th AVE S.E. Bnd(/e I Scour along abutm9n1 lurTNd poo1 19 207.9 LSP 7 Bridge 7.0 Bridge 7.0 Annornd 7 Arrno,ed 7 Reach 2 20 214.9 LGR 14 50% Willow 7.0 70% Willow and RCG 9.8 Sloped 14 Sloped 14 21 228.9 GLD 10 100% Willow and RCG 10.0 100% Willow and RCG 10.0 Vertical 10 Vertical 10 6 22 238.9 GLD 24 100% RCG and Wdlow 24.0 100% RCG and Willow 24.0 Vertical 24 Vertical 24 23 262.9 GLD 28.5 100%RCG 28.5 80% RCG and Willow 22.8 Sloped 28.5 Sloped 28.5 24 291.4 GLD 6.5 100%RCG 6.5 100%RCG 6.5 Vertical 6.5 Vertical 6.5 25 297.9 GLD 5.6 100% RCG 5.6 100%RCG 5.6 Vertical 5.6 Vertical 5.6 8.4 26 303.5 GLD 3.5 100% RCG and Willow 3.5 100% RCG and Willow 3.5 Undercut (.5M) 3.5 Vertical 3.5 27 307 GLD 46 80% Willow and RCG 36.8 60% WiDow 27.6 S~ped 46 S~ped 46 Scour llf1Ml'SI ~ willows fonned -,28 353 LSP 17.5 60% Wdlow and RCG 10.5 60% Willow and RCG 10.5 Sloped 17.5 Vertical 17.5 29 370.5 GLD 6.2 45% Willow 2.8 45% Willow 2.8 Vertical 6.2 Undercut (.3m) 6.2 30 376.7 GLD 14 100% Willow 14.0 100%Willow 14.0 Undercut (.3m) 14 Undercut (.3m) 14 &inJr lurTNd poo1 31 390.7 LSP 10 40% Willow 4.0 50% RCG and Willow 5.0 Undercut (.4m) 10 Undercut (.3m) 10 80% Vertical, 15% Scour around willow 32 400.7 LSP 15 70% RCG 10.5 30% Willow and RCG Sloped, 5% 4.5 Undercut (.2 -.Sm) 15 undercut (.2m) 12 60% vertical, 20% Reach 3 33 415.7 GLD 26 60% Willow and RCG 15.6 70% RCG sloped, 20% 18.2 undercut (.2m) 15.6 Undercut (.2-.4m) 26 Scour 1r,1/nsl bank. 1nd roots creat pool 34 441.7 LSP 19 80% RCG and Willow 15.2 80% RCG 15.2 Vertical 19 Vertical 19 Lonr,marah CrNlr AlJuvlaJ F1t1 35 460.7 GLD 12 30% RCG 3.6 10%RCG 1.2 Armored I Vertical 12 Sloped 12 36 472.7 GLD 61 60%RCG 36.6 60% RCG 36.6 S~ped 61 Sloped 61 100% RCG and Red 70%RCG 37 533.7 GLD 17 Alder 17.0 100% RCG 17.0 Sloped 17 Sloped 17 and bur -reed 38 550.7 GLD 16 40% RCG and roots 6.4 70% RCG 11.2 $_loped 16 S~ped 16 39 566.7 GLD 30 100%RCG 30.0 100%RCG 30.0 Sloped 30 Sloped 30 12 Reach 4 40 596.7 GLD 160 100% RCG 160.0 100%RCG 160.0 50% RCG Vertical 160 Vertical 160 and bur-reed 24 41 756.7 GLD 38 100% RCG 36.0 60% RCG 21.6 Sloped 36 Sloped 36 27 15%RCG 42 792.7 GLD 23 100%RCG 23.0 100% RCG 23.0 Sloped 23 Sloped 23 and bur-reed 100% RCG 43 815.7 GLD 17 100% RCG 17.0 100% RCG 17.0 Sloped 17 Sloped 17 and bur-reed 44 832.7 GLD 18 100%RCG 18.0 100% RCG 18.0 S~ped 18 Sloped 18 60% bur-reed 45 850.7 GLD 22 100% RCG 22.0 100% RCG 22.0 Sloped 22 Sloped 22 100%RCG 46 872.7 GLD 48 100% RCG 48.0 100% RCG 100%RCG 48.0 Sloped 48 Sloped 48 and bur-reed End I Upsnarn End al Red 8am Bddr,. I lndlan 11eM1ow C1"k ADINQI Fin 920.7 Page 8-2 15cl h#al l=ci l:!'!!tl\'I l=] . f:,w•.j ,~,, eeJ ~ ~ ~ t@:l ~ ~ ~ IB'l ~ ~ IMl Mtaiy Ciree~ Chtailiilliil®~ Re~t©irtait~©liil !Pir©]ecct King County Water and Land Resources Division C~ty ©~ Reliilt©liil Wet~tailiiltd Rtaitnliilgi Addendum to Wetland Delineation Report Dated ii/larch 10, 2010 Prepared for: King County Department of Parks and Natural Resources Water and Land Resources Division 201 South Jackson Street Seattle, WA 98104 Prepared by: Cindy Clark, Environmental Engineer King County Road Services Division Environmental Unit NovemfoeD' 17, 201 O City of Renton Planning Division . FEB 1 2, cUll C][TY OJF JRJENTON WETJLAND JRAT][NG This document is an addendum to the May Creek Channel Restoration Project Wetland Delineation Report prepared by King County Road Services Division, Environmental Unit, dated March I 0, 2010. The wetland delineation report described a large riverine wetland (total size approximately 140 acres) along a section of May Creek in southeastern King County near the cities of Renton and Newcastle. The project study area is located between River Mile (RM) 4.3 and 4.8 of May Creek, and included approximately 25 acres of the wetland complex (referred to as May Creek #5 in the King County Wetland Inventory (1990) ). The purpose of the wetland delineation was to identify the wetland boundary on the properties adjacent to May Creek where potential project impacts may occur. To determine the required buffer width, the wetland was also rated, using criteria referenced in the King County Critical Area Code (KCC 21A.318). King County adopts the Washington State's Department of Ecology: Washington State WetlandRating System for Western Washington (Hruby 2004). May Creek #5 was determined to be a Category fl riverine wetland with a 110 foot buffer, located in the natural JOO-year floodplain of May Creek. However, the portion of the study area/wetland that lies west of 148th Ave SE lies within the City of Renton jurisdiction, and therefore must also be classified using those criteria. The wetland, when rated using the City of Renton classification system, is a Category 3 wetland with a 25-foot buffer. The wetland is not a Category I wetland because it does not meet any of the following criteria: a. The presence of species listed by the Federal or State government as endangered or threatened, or the presence of essential habitat for those species; and/or b. Wetlands having forty percent (40%) to sixty percent (60%) permanent open water (in dispersed patches or otherwise) with two (2) or more vegetation classes; and/or c. Wetlands equal to or greater than ten (JO) acres in size and having three (3)·or more vegetation classes, one of which is open water; and/or d. The presence of plant associations of infrequent occurrence; or at the geographic limit of their occurrence The wetland is not a Category 2 wetland because it does not meet any of the following criteria: a. Wetlands that are not Category 1 or 3 wetland; and/or b. Wetlands that have heron rookeries or osprey nests, but are not Category 1 wetlands; and/or c. Wetlands of any size located at the headwaters of a watercourse, i.e., a wetland with a perennial or seasonal outflow channel, but with no defined influent channel, but are not Category I wetlands; and/or d. Wetlands having minimum existing evidence of human-related physical alteration such as diking, ditching or channelization 2 The wetland is a Category 3 _wetland because it meets criteria in (a): a. Wetlands that are severely disturbed. Severely disturbed wetlands are wetlands which meet the following criteria: I. Are characterized by hydrologic isolation, human-related hydrologic alterations such as diking, ditching, channelization and/or outlet modification; and 2. Have soils alterations such as the presence of fill, soil removal and/or compaction of soils; and 3. May have altered vegetation Criteria (b) and (c) under the Category 3 classification include newly emerging wetlands and all other wetlands not classified as a Category I or 2. These are not applicable since criteria defined in (a) are met. The hydrology within the wetland is partly controlled by May Creek, which has been channelized in the past. On the north side of the wetland, the wetland boundary closely follows a line of fill that appears to have been placed in wetland areas over the years to facilitate farm use. On the south side of the wetland, the wetland boundary more closely follows the natural valley topography. The wetland has also been degraded over the years by adjacent farming and agricultural uses. Many areas of the wetland are actively mowed and used for grazing horses and other livestock. The wetland received a higher rating based on the King County and Washington State classification system, and has a larger buffer under that system (I IO feet versus 25 feet with the City of Renton rating). The more conservative King County rating and buffer will be used when calculating project impacts and mitigation. 3 I I I I I I I I I I I I I I I I 1 I I I May Creek Channel Restoration Project King County Water and Land Resources Division Wetland Delineation Report Prepared for: King County Department of Parks and Natural Resources Water and Land Resources Division 201 South Jackson Street Seattle, WA 98104 Prepared by: Lindsey Miller, Environmental Engineer Cindy Clark, Environmental Engineer Todd Martin, Environmental Engineer King County Road Services Division Environmental Unit March 10, 2010 . ol Renton Cit'/ . oi11is1on piann1119 ft.\l \ '1 °LUI~ I I I I I I I I I I I I I I I I I I I Table of Contents Executive Summary ............................................................................................................ 3 I Introduction ................................................................................................................. 4 1.1 Study Objectives ................................................................................................. 4 1.2 Study Area .......................................................................................................... 4 2 Methods ....................................................................................................................... 6 2.1 Existing Literature Review ................................................................................. 6 2.2 Wetland Classification ........................................................................................ 6 2.3 Wetland Rating ................................................................................................... 7 2.4 Wetland Buffers .................................................................................................. 7 2.5 Delineation Methods ........................................................................................... 7 3 Wetland Description ................................................................................................. 11 3. I Landscape Setting ............................................................................................. 11 3.2 Hydrology ......................................................................................................... 12 3.3 Soils ................................................................................................................... 13 3.4 Vegetation ......................................................................................................... 14 3.5 Wetland Rating ................................................................................................. 16 3.6 Wetland Buffer .................................................................................................. 17 3. 7 Wetland Mitigation Ratios ................................................................................ 17 References ......................................................................................................................... 24 Appendix A -Wetland Rating Form ................................................................................ 26 Appendix B -Wetland Delineation Data Forms .............................................................. 27 Appendix C -Wetland Photos .......................................................................................... 28 List of Figures Figure 1-1: May Valley Vicinity Map ............................................................................... 5 Figure 3-1: May Valley Wetland Delineation in East Study Area ................................... 19 Figure 3-2: May Valley Wetland Delineation in West Study Area .................................. 20 Figure 3-3: NRCS Soil Survey Map of May Valley ......................................................... 21 Figure 3-4: National Wetland Inventory (NW!) Map of May Valley .............................. 22 Figure 3-5: USGS Topographic Map of May Valley ....................................................... 23 List of Tables Table 3-1: Wetland Vegetation Identified in May Creek #5 ........................................... 15 Table 3-2: Mitigation Ratios for Category II Wetlands in King County (KCC 21 A.24.340) ...................................................................................................................... 18 May Creek Channel Restoration Wetland Delineation 2 March 2010 I I I I I I I I I I I I I I I I I I I Executive Summary King County Department of Parks and Natural Resources (DNRP) is proposing to improve flow conditions and fish passage along approximately 1,500 feet of May Creek between River Mile (RM) 4.3 and 4.8 in the May Valley located in southeastern King County near the cities of Renton and Newcastle. One large riverine wetland, referred to as May Creek #5 in the King County Wetland Inventory (1990), is located in the project study area. This wetland is approximately 140 acres in total size, and approximately 25 acres of it is contained in the project study area and was delineated for this report. The purpose of this wetland delineation was to identify the wetland boundary on the properties adjacent to May Creek where potential project impacts may occur. Wetland area was delineated on multiple site visits using the definitions, methods, and standards established in Interim Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region (U.S. Army Corps of Engineer 2008) and the Washington State Wetlands Identification and Delineation Manual (WDOE 1997). May Creek #5 is a Category II riverine wetland with a 110 foot buffer, located in the natural 100-year floodplain of May Creek. While the wetland still received a high rating, it has been degraded over the years by adjacent farming and agricultural uses. Many areas of the wetland are actively mowed and used for grazing horses and other livestock. On the north side of the wetland, the wetland boundary closely follows a line of fill that appears to have been placed in wetland areas over the years to facilitate farm use. On the south side of the wetland, the wetland boundary more closely follows the natural valley topography. The hydrology source to the wetland is a combination of overbank flooding from May Creek and a high groundwater table. Numerous groundwater seeps were identified on the valley walls. The wetland is primarily palustrine emergent with some scrub- shrub/forested components that are concentrated near May Creek. The vegetation in this wetland has been degraded by the adjacent farming and agricultural uses. Many areas of the wetland are actively mowed and used for grazing, and therefore contain pasture grasses that could not be accurately identified given the season (late January) and regular mowing. In a majority of the wetland areas not regularly mowed, the dominant vegetation was reed canarygrass (Phalaris arundinacea), which grew in thick blankets with almost 100 percent coverage. The only unmowed areas without reed canarygrass were in the scrub-shrub/forested components of the wetland where the reed canarygrass was shaded out. This wetland, while fairly degraded due to adjacent land use practices, still received a Category II rating due to its high flood storage potential and opportunity, high opportunity to improve water quality, and its moderate potential to provide habitat to a variety of species. Any impacts to this wetland (permanent or temporary) resulting from this project will require mitigation as defined in the King County Critical Area Code (21 A.24.340). Those impacts will be quantified later in the project design process in a separate report. May Creek Channel Restoration Wetland Delineation 3 March 2010 King County Department of Parks and Natural Resources (DNRP) is proposing to improve flow conditions and fish passage along approximately 1,500 feet of May Creek between River Mile (RM) 4.3 and 4.9 in the May Valley (Sections 2 and 3, Township 23N, Range 5E) located in southeastern King County near the cities of Renton and Newcastle (Figure 1-1 ). Active horse pastures and farmland adjacent to May Creek are seasonally flooded and unusable due partially to ineffective flow capacity in this reach of May Creek. The reach of stream being investigated for potential improvement begins on the south side of SE May Valley Road approximately 0.1 mile downstream of 148th Avenue SE in Renton and includes the main stem of May Creek extending approximately 3,200 feet to a point just upstream from the confluence of May Creek with Indian Meadow Creek. Any project activities proposed in the stream will be completed in coordination with the adjacent property owners. One large riverine wetland, May Creek #5, is located in the study area, and is described in this report. 1. 1 Study Objectives The purpose of this wetland delineation was to identify the wetland boundary on the properties adjacent to May Creek where potential project impacts may occur. Wetland area was identified and flagged during multiple sites visits using the definitions, methods, and standards established in Interim Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region (U.S. Army Corps of Engineer 2008) and the Washington State Wetlands Identification and Delineation Manual (WDOE 1997). This study was undertaken to meet permitting requirements for the U.S. Army Corps of Engineers (Corps), Washington State Department of Ecology (Ecology), and King County Department of Development and Environmental Services (ODES). 1.2 Study Area The study area is located in the Cedar River -Lake Washington Watershed, Water Resource Inventory Area (WRIA) 8. The study area includes the properties on the north and south sides of May Creek starting approximately 0.1 mile downstream of 148th Avenue SE (RM 4.3) and continuing upstream to approximately RM 4.9 (Figure 1-1). The wetland described in this report continues to the east and west outside of the project study area and is identified as May Creek #5 in the King County Wetland Inventory (King County 1990). According to the King County Wetland Inventory, the entire wetland is approximately 140 acres. The full 140 acre wetland boundary was not delineated as part of this study. The boundary was delineated only in the area where potential impacts may occur from the proposed project activities. May Creek Channel Restoration Wetland Delineation 4 March 2010 I I I I I I I I I I I I I I -"tigrrre.,.-1!'Tvi~ ~erttfflnrffll ffflsmfatffl'n "'°o~t ,rciPffly• Legend e Study Area Limits City Boundaries o River Miles March 08 , 2010 450225 0 450 900 1,350 1,800 Feet ------ The Information included on this map has -compiled by King Counly Slaff from a variety of soon::es and Is S<Jl)jeCI to cnange wilhout nclice. King County makes no representations or warranties, express or Implied, as to aa:oracy. oompleleness, timeliness, or righlS to the use of such Information. This document is not intended for use as a SUMI)' prodUd. King Counly shall oot be liable for any general, special, Indirect. incidental, or consequential damages including, but not Umited to, tost revenues or lost p,otils resutjng from lhe use or misuse of lhe information contained on tNs map. N'f sale ol this map 0t N'lformation on l hls map Is prohiblled except by wrkten permission of King Counly. t'1 King County - I I I I I I I I I I I I I I I I I I I 2 Methods The methods used to delineate and characterize the May Creek #5 wetland are described in this chapter. 2.1 Existing Literature Review Prior to visiting the wetland site, ecologists carried out a review of relevant literature, surveys, studies and other works encompassing the cultural and ecological characteristics of the project vicinity and the wetland. Findings from historical topographic maps, aerial photographs, and other documents were incorporated into this report. The following existing documentation was reviewed as part of this study: o May Creek Basin Action Plan (King County 2001) o May Creek Drainage and Restoration Plan (GeoEngineers Inc. 2008) o May Creek Erosion Stabilization Draft Report -May Creek Sediment Transport Study Phase 3 (Anchor QEA LLC 2010) o King County Wetland Inventory (1990) o Washington State Department of Natural Resources Natural Heritage Program (2009) o U.S. Geologic Service (USGS) Topographic maps (1921) • U.S. Department of Agriculture (USDA) National Resources Conservation Service (NRCS) Web Soil Survey for King County (2009) o U.S. Fish and Wildlife Service National Wetland Inventory (USFWS 2010a) 2.2 Wetland Classification Wetlands were classified using both the U.S. Fish and Wildlife Service (USFWS) Cowardin habitats (Cowardin et al. 1979), and Washington State's hydrogeomorphic systems (Brinson 1993 and Hruby et al. 1999). 2.2.1 USFWS Cowardin Classification The USFWS Cowardin classification system (Cowardin et al. 1979) was developed as part of the National Wetlands Inventory (NW!) and used aerial photographs to identify and map wetlands to the greatest extent possible. This classification system identifies, gathers, and summarizes information on hydrologic, geomorphic, chemical and biological wetland characteristics. Specifically, water flow, water chemistry, substrate types, vegetation types, and dominant plant species are identified and characterized. Wetlands and their habitats are then classified based on the system (palustrine or estuarine, etc.), class ( dominant life form of vegetation or physiography and composition of the substrate) and by the dominant vegetation stratum and physiographic modifiers present (Cowardin et al. 1979). 2.2.2 Hydrogeomorphic (HGM) Classification The hydrogeomorphic (HGM) classification system (Brinson 1993 and Hruby et al. 1999) identifies and stratifies wetlands into hierarchical classes according to their differences or similarities in wetland functions (Brinson 1993). The HGM classification system complements the USFWS Cowardian system by identifying and categorizing wetlands based on their geomorphic setting (e.g., position of the wetland in the landscape), the source of water for the wetland (e.g., river, lake), and on the flow and fluctuation of the water in the wetland (e.g., hydrodynamics). 2.3 Wetland Rating The wetland within the project area was first characterized by its HGM class and then rated by the degree of hydro logic service, water quality enhancement, and habitat functions it provides using the wetland rating criteria referenced in the King County Critical Area Code (KCC 21A.3 l 8). King County adopts the Washington State's Department of Ecology: Washington State Wetland Rating System for Western Washington (Hruby 2004 ). In King County, wetlands are classified into Category I through IV based on the combination of each wetland's HGM class, rarity and sensitivity, and the cumulative point scores of specific, actual and/or potential, physiobiological functions they may provide based on the wetland characteristics and its surrounding landscape context. Category I wetlands provide the highest wetland function and are difficult to replace, while Category IV wetlands are degraded and disturbed wetlands providing limited function. The completed wetland rating form for May Creek #5 can be found in Appendix A. 2.4 Wetland Buffers A fixed buffer width was subsequently assigned to the wetland based on the wetland's score in the rating system as defined in the King County Critical Area Code (KCC 21A.24.325). These buffer widths are further modified based on the wetland's location with respect to the Urban Growth Boundary, habitat functions performed, and the intensity of disturbance from adjacent land use (KCC 21 A.24.325). Buffer widths are measured horizontally from the edge of the wetland boundary. Although King County Code stipulates specific fixed buffer widths, the code also allows incremental variations, buffer averaging and other variances from fixed standards based on site-specific features or the type of action anticipated. King County ODES is responsible for officially implementing the required buffer protection and/or approving variances from fixed widths. 2.5 Delineation Methods King County ecologists visited the project site on five separate days (January 21, 26, and 28, 2010, February 24, 2010 and March I, 2010) to delineate the wetland described in this report. They used the guidance provided in the Interim Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region (U.S. Army Corps of Engineer 2008) and the Washington State Wetlands Identification and Delineation Manual (WDOE 1997) to delineate and characterize the wetland. Potential wetlands were first identified on the dominance of hydrophytic vegetation and both surface and subsurface hydrology. Then, a more detailed analysis of hydrology, soil, and vegetation were performed to confirm the presence of the wetland and its boundary. This analysis is described in more detail later in this section. May Creek Channel Restoration Wetland Delineation 7 March 2010 I I I I I I I I I I I I I D I I I I I I I I I I I I I I I I I I I I I I I The information collected during these investigations was recorded on the Wetland Determination Data Form from the Interim Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region (U.S. Army Corps of Engineer 2008). Completed data forms are attached in Appendix B. Based on information from the three wetland field indicators (hydrology, soils, and vegetation), the boundaries of the wetland were flagged in the field (when possible) and the flag locations were recorded with a GPS unit (Trimble GeoXT Explorer). It was not possible to hang flags along the entire wetland boundary because some wetland areas extended into pastures with active horse use. When it was possible to enter a horse pasture, the GPS unit was used to note the wetland boundary points but no flags were hung. 2.5.1 Hydrology Permanent or periodic inundation (where soil is saturated within the rooting zone at least seasonally) is the hydrologic force behind wetland formation. The presence of water for 12.5 percent or more of the growing season typically creates an anaerobic condition in the soil, which affects the types of plants that grow and the types of soils that develop (WDOE 1997). Hydrological characteristics of the area were assessed to determine the hydrologic control (i.e., the determinants of inflow and outflow of water to and from the area) and the capability of the area to pond surface water. The presence of surface water, depth to groundwater, and depth to saturation was recorded at each soil pit location and can be found in the data forms in Appendix B. Other indicators of wetland hydrology included signs of lengthy inundation, unique drainage patterns, drift lines, watermarks on vegetation and other structures, sediment deposits, water-stained leaves, and hydrophytic vegetation (i.e., plants with morphological adaptations [e.g., adventitious roots] for survival in saturated soils). 2.5.2 Soil Hydric soils are defined as soils that are flooded, ponded, or saturated long enough during the growing season to develop anaerobic conditions in the upper part of the soil profile (WDOE 1997). Anaerobic conditions are created when flooding, ponding, or saturation is of sufficient duration to result in the absence of oxygen. These soils usually support hydrophytic vegetation. A common indicator ofhydric soil in this part of Washington is a "Depleted [Gray] Matrix" (U.S. Army Corps of Engineer, 2008). Hydric soil meeting this criteria must have a layer at least 6 inches thick starting within l O inches of the mineral soil surface, and that has a depleted matrix with at least 60 percent of that layer having a chroma less than or equal to 2. Soil pits were dug in representative locations throughout the wetland to characterize the soil and to determine the presence of hydric soil which helped identify the wetland boundary. The soil pits were dug to at least 18 inches in depth and the characteristics May Creek Channel Restoration Wetland Delineation 8 March 2010 were recorded on the data forms found in Appendix B. Soil auger holes, typically dug to at least 16 inches, were used in between soil pits to help establish the presence or absence of hydric soil indicators and to help identify or confirm wetland boundaries. Soil auger holes were also used in the pasture areas with active horse use, where large soil pits were not permitted. The soil profile was described using the standard USDA NRCS Soil Conservation Service (1981) system. Soil texture and color was described using Munsell Soil Color charts assessed for hydric condition (Munsell 2009). 2.5.3 Vegetation Hydrophytic vegetation is defined as plant life growing in water or soil, or on a substrate that is at least periodically deficient in oxygen as a result of excessive water content (WDOE 1997). Vascular plants can be classified in five groups according to the plant's affinity for wetland areas (Reed 1988). These groups are described as follows: o Obligate Wetland (OBL): Occur almost always (estimated probability> 99 percent) under natural conditions in wetlands. o Facultative Wetland (FACW): Usually occur in wetlands (estimated probability 67 to 99 percent), but occasionally found in nonwetlands. o Facultative (FAC): Equally likely to occur in wetlands and non wetlands ( estimated probability 34 to 66 percent). o Facultative Upland (FACU): Usually occur in nonwetlands (estimated probability 67 to 99 percent), but occasionally found in wetlands ( estimated probability I to 33 percent). o Obligate Upland (UPL): Occur in wetlands in another region, but occur almost always ( estimated probability< 99 percent) under natural conditions in non wetlands in the region speci tied. An area has hydrophytic vegetation when more than 50 percent of the dominant species from all strata are OBL, FACW, and/or FAC species, which are on lists of plant species that occur in wetlands. When either all considered species are F AC or the number of species wetter than F AC equals the number of species drier than F AC, the wetland determination is based on soil and hydrology parameters. Other indicators of hydrophytic vegetation can also be considered in difficult situations. These include observed morphological adaptations of plants to an inundated or flooded environment or review of technical literature. The dominance and locations of hydrophytic vegetation assisted in delineating the wetland boundaries. Vegetation plots were created and analyzed at the soil test pit locations and the vegetation at these locations was recorded on the data forms in Appendix B. The common and scientific plant names and indicator status (OBL, F ACW, May Creek Channel Restoration Wetland Delineation 9 March 2010 I I I I I I I I D I I I I I I I 3 WeUa1111dl Descll'iptio1111 This section describes the existing conditions of the wetland located in May Valley, referred to as May Creek #5 in the King County Wetland Inventory (1990). The King County Wetland Inventory indicates that this wetland is approximately 140 acres. Approximately 25 acres of this wetland are contained within the project study area. 3. 1 landscape Setting May Creek #5 is a riverine wetland located in the mapped l 00-year floodplain of May Creek (WRIA Stream #08.0282). May Creek is a 7-mile stream in the Lake Washington Watershed (WRIA 8). The stream originates in the steep forested slopes of Cougar and Squak Mountains, and flows northwesterly eventually draining into the southern portion of Lake Washington. In the project study area May Creek flows through May Valley, a natural floodplain that has historically been prone to flooding. The May Creek #5 wetland covers the majority of the May Valley. According to the May Creek Current and Future Conditions Report (King County l 995) May Creek has been channelized and dredged throughout the May Valley since at least l 936. King County continued to dredge May Valley in the l940's and deposited the material onto the surrounding properties. This dredging reduced the duration and extent of flooding in the May Valley and allowed property owners to use the land for agriculture and grazing livestock. Regular dredging appears to have ceased sometime after the l 940's due to increasing protection of sensitive areas. Today, the majority of the properties in the May Valley are rural residential with active agriculture and grazing; however, the lack of dredging activities over the last 50 years means that May Valley is once again experiencing prolonged periods of flooding during the wet season. This flooding limits the amount of area that residents can use for agriculture and grazing. During the wet season, horses and other livestock are either moved to areas located on the higher valley slopes or to areas that appear to have been raised out of the floodplain (over many years) with fill. While the current extent of the flooding limits horse pasture use, it is likely that it is closer to natural historical conditions pre-development. In the northeast quadrant of the study area, where farm use is the most pronounced, the wetland boundary closely follows the fence line associated with the horse pastures. Over the years, fill appears to have been placed in the wetland to increase usable farm area. The wetland boundary in the southeast quadrant of the study area is also located in horse pastures, but more closely follows the natural valley topography (Figure 3-1 ). In the undeveloped area in the northwest quadrant of the study area, the wetland boundary extends into the scrub-shrub/forested areas located at the toe of the valley wall, with one exception; In the most northwestern quadrant of the study area it appears that fill was placed in the wetland many years ago to accommodate a home that no longer exists (Figure 3-2). Remnants of the old buildings can be seen in this area. The wetland boundary in the undeveloped areas in the southwestern quadrant of the study area, closely follows the topography and is easily visible by a change in vegetation (reed May Creek Channel Restoration Wetland Delineation 11 March 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I canarygrass (Phalaris arundinacea) to Himalayan blackberry (Rubus procerus). In a small area directly west side of 148th A venue NE it appears that fill was placed in the wetland. The boundary in this area is irregular (it does not follow the natural topography) and is demarcated by large patches of scotch broom ( Cytisus scoparius) and an unknown pasture grass (Figure 3-2). 3.2 Hydrology The primary source of hydrology to the May Creek #5 wetland is a combination of overbank flooding and a high groundwater table. Multiple groundwater seeps were visible on the valley walls at higher elevations. Two tributaries flow south off the northern hillside and one tributary flows north from the southern side of the project area, providing additional sources of hydrology. Many areas of this wetland are frequently flooded (at least once every 2 years) by May Creek, and therefore May Creek #5 would be classified as a riverine wetland using HGM system (Hruby 2004). It should be noted that riverine wetlands also commonly receive significant amounts of water from other sources such as groundwater and slope discharges (Hruby 2004) as is the case in the May Valley. A wetland hydroperiod is the period of time during which the wetland is covered by water. Hydroperiods in this wetland include areas that are seasonally flooded and areas that appear to be only occasionally flooded at higher elevations. At even higher elevations along the valley walls, soil is saturated and hydrology is driven by primarily groundwater seeps. Overbank flooding in these higher areas is limited. Wetland Soil Pit #I (Figure 3-2) was located on the south side of May Creek on the east side of 148th Avenue SE approximately 35 feet from the stream. Indicators of hydrology at this location included visible observation of surface water (within IO feet of the soil pit) high water table (present at 8 inches below the surface), soil saturated to the surface, water marks, and water stained leaves. Based on the strong hydrology indicators at this location, it was assumed that hydrology would be present at this location and in locations at a similar elevation throughout the growing season. Wetland Soil Pit #3 (Figure 3-1) was located on the south side of May Creek on the eastern side of the study area at a higher elevation than the first pit. This area does not appear to receive regular overbank flooding due to its elevation; however other indicators of hydrology included a high water table (present 5.5 inches below the ground surface), and soil saturated to the surface. Groundwater seeps were also identified nearby at similar elevations. Wetland Soil Pit #4 (Figure 3-2) was located on the north side of May Creek on the east side of 148th Avenue SE. Indicators of hydrology in this area included a high water table (present 4.5 inches below the ground surface), soil saturation to the surface, water marks, algal mat, water-stained leaves, a hydrogen sulfide odor, and oxidized rhizospheres along living roots. May Creek Channel Restoration Wetland Delineation 12 March 2010 Wetland Soil Pit #6 (Figure 3-2) was located.on the north side of May Creek and on the west side of 148th Avenue SE. This area is probably too far from the stream to receive regular overbank flooding, but indicators of hydrology in this location include a high water table (present 9 inches below the ground surface) and soil saturated to the surface. Wetland Soil Pit #7 (Figure 3-2) was located on the south side of May Creek and on the west side of 148th Avenue SE. This area probably receives overbank flooding from May Creek during annual storm events. Indicators of hydrology on the field day included a high water table (present 12 inches below the surface) and saturated soil to the surface. A soil pit was not dug in the northeastern quadrant of the study area because the wetland area extended into active horse pastures (Figure 3-1 ). In these areas hydrology indicators included visual observation of surface water (seeps), water marks, water stained leaves, and a high water table that was observable using a soil auger. Upland Soil Pits #2 and #5 (Figure 3-2), near Wetland Soil Pits #1 and #5 respectively, did not contain any hydrology indicators. The water table was not present at 18 inches below the surface, and the soil was not saturated. 3.3 Soils The NRCS Web Soil Survey (2009) indicates that Bellingham silty loam (Bh) is found at the lower elevations in the May Valley (Figure 3-3). The Ragnar-Indianola association (RdC) is found on the higher elevations on the south side of the May Valley, and Alderwood gravelly sandy loam (AgC and AgD) is found on the north side of May Valley, Alderwood gravelly sand loam (AgC) and Bellingham silty loam (Bh) are both on the NRCS hydric soil list for Washington State. Field visits confirmed the presence of these hydric soils in the May Valley. In addition, the field visits found a thick layer of clay in the western half of the study area. Wetland Soil Pit #I contained one uniform soil horizon from Oto 18 inches below the surface. The soil was a black clay (IOYR 2/1) with redoximorphic (redox) features (soil mottling) that were too small to color. Redox features are soil properties, associated with wetness, which results from the reduction and oxidation of iron and manganese compounds in the soil after water saturation and desaturation, respectively. Soil mottles are commonly identified redox features. The redox features were concentrations covering about I percent of the matrix. This soil meets the criteria F3 for hydric soil ( depleted matrix with a layer at least 6 inches thick starting within IO inches of the mineral soil surface). Wetland Soil Pit #3 contained three soil horizons. The first horizon (from Oto 6.5 inches) was a black loamy sand (5YR 2.5/l) without redox features. This soil meets the criteria F3 for hydric soil ( depleted matrix with a layer at least 6 inches thick starting with 10 inches of the mineral soil surface). The second horizon (from 6.5 to 11.5 inches) was a yellowish brown silty loam (IOYR 5/4) with redox features in approximately 10 percent of the matrix. The third horizon ( 11.5 inches to 18 inches) was a dark yellowish brown silty loam (lOYR 4/6) without any redox features. The second two horizons did not meet May Creek Channel Restoration Wetland Delineation 13 March 2010 I I I I I I I I I I i I I I I I I I I I I I I I I I I fi I I I I I the criteria for hydric soil; however, since the first horizon met the criteria for hydric soil, this sampled area was determined to be inside the wetland. Wetland Soil Pit #4 also contained three soil horizons. The first horizon (0 to 8.5 inches) was a black clay (IO YR 2/1) without any redox features. The second horizon (8.5 to 13.5 inches) was also a black clay (2.5 YR 2.5/l) with 50 percent coverage ofredox features. The third horizon (13.5 to 18 inches) was again a black clay (IOYR 2/l) without any redox features. This soil meets the criteria F3 for hydric soil ( depleted matrix with a layer at least 6 inches thick starting with IO inches of the mineral soil surface). Wetland Soil Pit #6 contained two soil horizons. The first horizon (0 to 5 inches) was the same black clay (IO YR 2/1) without redox features that was observed in Soil Pit #4. The second horizon (5 tol8 inches) was the same black clay but it contained faint redox feature in about 20 percent of the matrix. This soil meets the criteria F3 for hydric soil ( depleted matrix with a layer at least 6 inches thick starting with IO inches of the mineral soil surface). Wetland Soil Pit #7 had a two inch duff layer that was followed by one uniform horizon (2 to 18 inches). This horizon was a very dark grayish brown (IOYR 3/2) clay layer with yellowish red redox features (5 YR 5/8) in 20 percent of the matrix. This soil meets the criteria F3 for hydric soil ( depleted matrix with a layer at least 6 inches thick starting with IO inches of the mineral soil surface). Soil pits were not dug in the northeastern quadrant of the study area because the wetland area extended into active horse pastures. In these areas, the soil was sampled using a soil auger and examined for hydric indicators. The soil in this area had similar characteristics as what was recorded for Soil Pit #3. Upland Soil Pits #2 and #5, near Wetland Soil Pits #1 and #5 respectively, did not contain any indicators ofhydric soil. The soil chroma (3 and 4) was too high to meet the criteria for a depleted matrix, and the soil did not exhibit any other hydric indictors. 3.4 Vegetation According to the NW!, May Creek #5 is a palustrine wetland with primarily emergent vegetation. This is consistent with what was found in the field; however, in addition, many portions of the wetland immediately adjacent to May Creek also contain a scrub- shrub vegetation component. A smaller portion of the wetland could be considered forested (Figure 3-4). The vegetation in this wetland has been degraded by adjacent farming and agricultural uses. Many areas of the wetland are actively mowed and used for grazing, and therefore contain pasture grasses that could not be accurately identified given the season (late January) and regular mowing. In a majority of the wetland areas not regularly mowed, the dominant vegetation was reed canarygrass which grew thick blankets with almost I 00 percent coverage. On the western side of the wetland, hardhack (Spirea douglasii) out- May Creek Channel Restoration Wetland Delineation 14 March 2010 ------------------------------------------ competed the reed canarygrass is some areas. The only unmowed areas without reed canarygrass were in the scrub-shrub/forested components of the wetland where the reed canarygrass was shaded out. The dominant vegetation in the scrub-shrub/forested portions of the wetland were willow species (Salix spp.), red alder (A/nus rubra), and Oregon ash (Fraxinus latifolia). A portion of the scrub-shrub vegetation along May Creek was planted in the past IO years by King County DNRP to improve riparian coverage and shade out the reed canarygrass. A complete list of the vegetation identified in the wetland is shown in Table 3-1 with its Latin name, common name, wetland indicator status, and whether or not it was a dominate species in any of the areas surveyed. A species was considered dominant if it had at least 20 percent absolute coverage within its stratum. T b a le 3-1: Wetland V eaetation Identified in Mav Creek #5 Latin Name Common Name Dominant Herb Stratum Carex obmwta slough sedge No Eauisetum telmateia giant horsetail No Juncus effusus soft rush Yes Lvsichitum americananum skunk cabbage No Phalaris arundinacea reed canarvi,rass Yes Polvstichum munitum sword fem No Ranuncu/us renens creeping buttercup No unknown moss Yes unknown various pasture grasses Yes ShrubNine Stratum Amelanchier a/nifolia Saskatoon serviceberrv Yes Cornus sericea red-osier dogwood No Oemleria cerasiformis Indian olum Yes Phvsocarous cavitatus Pacific ninebark No Rosa nisocama peafruit rose Yes Rubus vrocerus Himalavan blackberrv Yes Rubus svectabilis Salmon berry Yes Salix hookeriana Hooker's willow Yes Salix /asiandra Pacific willow Yes Salix scouleriana Scouler's willow Yes Salix sitchensis sitka willow Yes Svirea dou,dasii hardhack Yes Svmnhoricarnos a/bus snowberrv No Tree Stratum A/nus rubra red alder Yes Fraxinus latifolia Oregon ash Yes Picea sitchensis Sitka spruce No Prunus snn. Cherrv Yes Pseudotsuf!a menziesii Douglas fir Yes Thuia vliclata Western red cedar Yes unknown ornamental fruit trees No *Identifies a tentative assignment based on conflicting reviews May Creek Channel Restoration Wetland Delineation 15 Indicator Status OBL FACW FACW OBL FACW FACU FACW unknown unknown FACU FACW FACU FACW FAC FACU FAC FACW FACW FAC FACW FACW FACU FAC FACW FAC FACU FACU* FAC unknown March 2010 I I I I I I I I I I I I fl I I I I I I I I I I I I I I I I I I I I Upland vegetation in the wetland buffer included ornamental maple (Acer sp.), Indian plum (Oemleria cerasiformis), beaked hazelnut (Cory/us cornuta), unknown fruit trees, Himalayan blackberry, sword fem (Polystichum munitum ), bracken fem (Pteridium aquilinum), tall fescue (Festuca arundinacea), orchard grass (Datcty/is glomerata), bentgrass (Agrostis sp. ), scotch broom, and unknown thistle species. 3.5 Wetland Rating The wetland in the study area was rated as one unit using the Washington State Wetland Rating System for Western Washington (Hruby 2004). According to the guidance in the rating system, when a stream that is less than 50 feet wide bisects a contiguous vegetated wetland, wetland area on both sides of the stream should be treated as a single unit (Hruby 2004). Additionally, even though the wetland is divided by 148th Avenue SE, the wetland was not divided into separate units for the purposes of the rating system because there is a level surface-water connection (May Creek) between the two parts of the wetland (Hruby 2004 ). Under the Washington State Wetland Rating System for Western Washington, May Creek #5 is a Category II riverine wetland scoring 61 out of 100 points (Appendix A). The wetland provides moderate water quality function (scoring 14 points). The wetland has high opportunity to improve water quality due to the close proximity of grazing, roadways, and residential development; however, its potential to improve water quality is only moderate due to a lack of ungrazed herbaceous vegetation and trees/shrubs in the wetland. The wetland provides high hydrologic function (scoring 26 points). The wetland has the opportunity to reduce flooding and erosion due to the roads and bridges downstream, as well as potential salmon habitat. In addition, due to the large amount of available flood storage it also has a high potential to reduce flooding and erosion. The wetland provides moderate habitat function (scoring 21 points). The wetland has high potential to provide habitat for many species because it is large enough ( over 140 acres) to contain multiple vegetation classes, hydroperiods, and a richness of plant species. On the other hand, the opportunity that this wetland has to provide habitat is limited due to disturbed buffers and active grazing adjacent to much of the wetland, as well as disturbed connections to other vegetated corridors or wetlands. Wildlife observations in the study area during the wetland survey included over 25 species of birds, including great blue heron (Ardea herodias) and red-tailed hawk (Buteo jamaicensis), as well as Columbia black-tailed deer (Odocoi/eus hemionus columbianus), raccoon (Procyon /otor) and coyote (Canis la/rans). This wetland rating is preliminary and should not be considered final until King County ODES has reviewed and approved this report. May Creek Channel Restoration Wetland Delineation 16 March 2010 3.6 Wetland Buffer The buffer for this wetland would be 110 feet according King County Code 21 A.24.325. The wetland buffer is determined by using the wetland rating (Category II), in conjunction with the wetland habitat score (2 l points), and the adjacent land use (moderate impact). Moderate adjacent impact land use is assumed due to agricultural use on some of the adjacent properties without an approved farm management plan. Two of the farms adjacent to the wetland have farm management plans, but the other farms and properties do not. In addition, the majority of the wetland buffer contains paved areas, buildings, and pastures. These areas provide limited wetland buffer function. This wetland buffer is preliminary should not be considered final until King County DDES has reviewed and approved this report. 3. 7 Wetland Mitigation Ratios King County Code 21 A.24.340 defines mitigation replacement ratios to compensate for adverse effects to a wetland or its buffer. The mitigation replacement ratio is based on the wetland category of the impacted wetland and the type of mitigation proposed to compensate for the impact. King County Code also adjusts mitigation replacement ratios based on the type of impact (permanent or temporary). A permanent impact would be placing permanent fill in the wetland or permanently dewatering a portion of wetland. A temporary impact would be conversion of a scrub-shrub/forested wetland to an emergent wetland, or temporary vegetation removal associated with construction activities. Alterations to a wetland buffer require compensation at a simple I: I ratio (i.e., I acre of mitigation for every I acre of impact). Table 3-2 summarizes the mitigation replacement ratios for Category II wetlands according to King County Code 2 !A.24.340. The impacts resulting from the project activities, as well as any required mitigation will be analyzed in a separate report. May Creek Channel Restoration Wetland Delineation 17 March 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Table 3-2: Mitigation Ratios for Category II Wetlands in King Countv IKCC 21A.24.3401 Impact Type Wetland reestablishment or creation Permanent fill or 3:1 dewatering Conversion of forested/scrub-1.5:1 shrub to emergent Temporary construction 0.75:1 impacts May Creek Channel Restoration Wetland Delineation Mitigation Type 1 :1 Wetland Wetland reestablishment or Wetland rehabilitation wetland creation (R/C) enhancement and wetland only enhancement (E) 8:1 1 :1 RIC and 4:1 E 12:1 2:1 N/A 3:1 1:1 N/A 1.5:1 18 March 2010 --~rr'J-~M~ vfflle~dfl'dnffl:>Effltielnorffn ~st'!tu~ Affla • Legend + Tribs or Seeps Streets o Soil Pit Wetland Buffer 11 O' Wetland • Wetland GPS Points March 08 , 2010 130 65 0 130 260 390 520 Feet ------ The infonnatlon Included on lhis map has been compiled by King County sta" from a variety of sources and Is subject to d\ange without notice. King County makes no repn,980tatlons or warranties, express or ..-.,lied. as ID aocuracy, a,mpletaness, timeliness, or rights to the use of such Information. This document Is not Intended klr use as a SLVVey product. King County shall not be liable for any general, opedal, ildlred, Incidental, or coosequenllal damages Including , but not limited 10. lost revenues or lost profits resulling from the use or misuse ol lhe Information contained on lhls map. /V'i sale ol lhls map or Information on this map Is prohibited except by written pe<mission of King County. lQ King County - -• F~r~-~~Vffl'Pe~eftn~effl'temforffll ~s~t~ Affia• Legend + Tribs or Seeps Streets o Soil Pit Wetland Buffer 11 O' Wetland • Wetland GPS Points March 0 8, 2010 100 50 0 100 200 300 400 Feet ------ The information Included on this map has bMn compiled by King Coonty staff from a variety of soun:es and Is subject to ct,angewtthoot nolice. Kiog Coonty makes no representations or watrantles, exprass or ln'9ied, as to accuracy, oompleteness, 11m81iness, or rights 1e the use or such ntonnation. This document Is not Intended for use as a su,,,ey product. Kiog Coonty shall not be liable for any genen,1, special, iidirec:t. Incidental, or consequential damages including, but oot llrrlted to, lost revenues or lost profits rasuling from the use or misuse of the lnlormation contained on this map. ,.,,, sale of this map or inlonnallon on this map Is prohlbl1ed except by wrllen perrri$sioo of King Coonty. UI King County - ---~ig'l!fe ~: ~~ sefl 38, v~ ~ fflvl~ Vfflef" -- 310155 0 310 620 930 1,240 Feet ------ March 08, 20 10 N Legend NRCS Soil Survey Soil Types + 1111 AgC (Alderwood Gravelly Sandy Loam) -AgD (Alderwood Gravelly Sandy Loam) 1111 BeD (Beausite Sandy Loam) 1111 Bh (Bellingham Silt Loam) 1111 EvB (Everett Gravelly Sandy Loam) 1111 EvC (Everett Gravelly Sandy Loam) --OvC (Ovall Gravelly Loam) 1111 OvD (Ovall Gravelly Loam) 1111 RdC (Ragnar-Indianola association) The Information Included on this map has been ~ by King County staff from a variety ol sources and is sulljecl ID change without notice. King County makes no representatons Of warrandes, expn,ss o, Implied, as to aoc:uracy, completeness, timeliness. °' rights lo the use of such Information. This document Is not intended for use as a SLWVeY product. King County shal not be liable for any general , special , 1nc1,ec1, ioadental, °' consequenbal -_. inducing, bot not limited to, lost revenues Of lost proli1s resullng from the I use or misuse of the Information conll>ined on lhls map. My sale ol lhls map°' Information on this map is prohibited except by written permission ol King County. ti King County - -a,=i~e"'-4~amnmv~rfflll nfflntffl\, ~~ o"'1a'r\l fty• 480240 0 480 960 1,440 1,920 Feet ------ March 08, 2010 Legend USFWS NWI Wetlands Classes N + PEMAd (Palustrine Emergent Temporarily Flooded Partially Drained) 11111 PEMC (Palustrine Emergent Seasonally Flooded) PEMCd (Palustrine Emergent Seasonally Flooded Partially Drained} 11111 PEMF (Palustrine Emergent Semipermanently Flooded) 11111 PFOC (Palustrine Forested Seasonally Flooded) ::::::J PFOCd (Palustrine Forested Seasonally Flooded Partially Drained) 1111 PSSC (Palustrine Scrub-Shrub Seasonally Flooded} 11111 PSSCd (Palustrine Scrub-Shrub Seasonally Flooded Partially Drained) The Information lnduclad on this map haS been complied by King County staff from a variety of sources and Is subjed to cnango wtthout notica. King County makes no repn,sentatioos o, warranties, express o, implied, as to accuracy. a,mpleleness, limellness, o, rigllts 10 the use of such r,fonnation. This documenl Is not Intended for use as a survey product. King County shall not be liable fo, any _..i, spedal, ''" lndir8ct, lnc:identat, o, consequential damages lndudlng, bu1 no4 limited to. lost revenues or loot p<olits resuling from the use Of misuse of the information contained on this map. Any sale of this map o, information on this map is p,ohiblted •"""l'I by wrtten pern,lssion of King County. UJ King County - ---,igffl'e ~: "'3~ ~o~a~c ~p'ffl ~ ~11~(1~11'9 - The lnfonnation Included on ll1is map has been compiled by Klng County staff from a va,iety of sources and Is subject to ~ ~' '~! J' r~ttwtlr ~ ~~~~m-ta~narranties,exprass ~--··%~-~-:-:.,-~4·~ JZ=s===·~-~·~~~~~~!~;:::·::::::ls 480240 0 480 960 1,440 1,920 Feet ------ Klng Coonly shall not be Hable 10< any gene,al. special, Indirect. lnadentat Of consequential damages Including, but not -to, lost mvenues or lost profits resoling from the use« misuse ol the information contained on this map. ~ ~..._ ~ lvry salt cl this map Of information on t Ns map Is prohibited except by wrlton pennlssion of King County. March 08, 2010 UI King County - I I I I I I I I I I I I I I I I I I I References Anchor QEA LLC., 2010. May Creek Erosion Stabilization Draft Report -May Creek Sediment Transport Study Phase 3. January 2010. Prepared for King County Department of Parks and Natural Resources. Seattle, Washington. Available online at: http://www.kingcounty.gov/environment/watersheds/cedar-river-lake- wa/may-creek/erosion-stabilization-report.aspx (Accessed February 2010) Brinson, M. M. 1993. A hydrogeomorphic classification for wetlands. U.S. Army Corps of Engineers, Waterways Experiment Station, Vicksburg, MS. Tech. Rep. WRP- DE-4. Brinson, M. M, Hauer, FR., Lee, L. C., Nutter, W. L., Smith, R.D., Whigham, D. 1994. Guidebook for Application of Hydrogeomorphic Assessments to Riverine Wetlands. 203pp. Cooke, S.S. ed. 1997. A Field Guide to the Common Wetland Plants of Western Washington and Northwestern Oregon. Seattle Audubon Society Washington Native Plant Society.417 pp. Cowardin, L. M., V. Carter, F.C. Golet and E.T. LaRoe. (1979). Classification of wetlands and deepwater habitat of the United States. Washington D.C., USA, U. S. Fish and Wildlife Service: 103pp. GeoEngineers Inc., 2008. Final Draft May Creek Drainage and Restoration Plan. December l 9, 2008. Prepared for King County Water and Land Resources Division. Seattle, Washington. Hruby, T, T. Granger, K. Brunner, S. Cooke, K. Dublanica, R. Gersib, L. Reinelt, K. Richter, D. Sheldon, E. Teachout, A. Wald, and F. Weinmann. July 1999. Methods for Assessing Wetland Functions Volume I: Riverine and Depressional Wetlands in the Lowlands of Western Washington. WA State Department Ecology Publication #99-115. Hruby, T. 2004. Washington State wetland rating system for western Washington - Revised. Washington State Department of Ecology Publication# 04-06-025. King County Environmental Division. 1990. King County Wetland Inventory. Department of Parks, Planning, and Resources, King County, Washington. King County and City of Renton. l 995. May Creek Current and Future Conditions Report. King County Surface Water Management Division and Renton Department of Public Works, August 1995. Seattle, Washington. May Creek Channel Restoration Wetland Delineation 24 March 2010 King County and City of Renton. 200 I. Final Adopted May Creek Basin Action Plan. King County Surface Water Management Division and Renton Department of Public Works, April 2001. Seattle,Washington. Available online at: http://www.kingcounty.gov/environment/watersheds/cedar-river-lake-wa/may- creek/may-creek-basin-plan.aspx (accessed February 2010) Munsell Soil Color Charts (2009). (http://www.munsellstore.com/index.cfm/MenuitemID/468/MenuGroup/Home.ht m) Date Accessed 4/20/09 Reed, P.B., Jr. 1988. National list of plant species that occur in wetlands: Northwest (Region 9). U.S. Dept. of the Interior, Fish and Wildlife Service. Biological Report 88 (26.9). 89 pp. USFWS (U.S. Fish and Wildlife Service). 2010a. National Wetland Inventory from Wetlands Online mapper located at http://www.fws.gov/wetlands/Data/mapper.html (accessed January 2010) USFWS (U.S. Fish and Wildlife Service). 2010b. Wetlands and Deepwater Habitats Classification -National Wetlands Inventory Mapping Code Description. Available online: http://www.fws.gov/wetlands/Data/webatx/atx.html (accessed September 2009) USDA Natural Resources Conservation Service. 2009. Soil Survey of King County, Washington. Version 6, September 22, 2009. Online mapper located at http://websoilsurvey.nrcs.usda.gov/app/HomePage.htm (accessed January 20 I 0) USGS (U.S. Coast and Geodetic Survey) (1900). Washington: Tacoma Quadrangle. March 1900 edition (Surveyed in 1894-1895). Tacoma, WA, USO! -U.S. Geological Survey: Topographic Map. WDOE (Washington Department of Ecology) (1997). Washington State Wetlands Identification and Delineation Manual. Olympia, WA, Department of Ecology: 88 plus Appendices. DNR (Washington Department of Natural Resources). 2009. Natural Heritage Program Wetland Information. July 21, 2009. Olympia, Washington. Available online at: http://www1.dnr.wa.gov/nhp/refdesk/datasearch/index.html (Accessed February 2010) May Creek Channel Restoration Wetland Delineation 25 March 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Wetland name or number WETLAND RA TING FORM -WESTERN WASHINGTON Version 2 -Updated July 2006 to increase accuracy and reproducibility among users Updated Oct 2008 with the new WDFW definitions for priority habitats t/:J/ /Z-b/0 0 J/2.o/::J.O/l> Name of wetland (if known): ~fvl~~"-+-0'--'-'U"'-"-=k~-=tf-"5 ______ Date of site visit: 1/2-g/.::u, 10, :,./;,1'-1/::u,10 Rated by l-fv1 , c_e, , TM Trained by Ecology? Yes_No_ Date of training __ _ SEC:2 13 TWNSHP:;JN RNGE: _;if_ ls S/T/R in Appendix D? Yes_ No X Map of wetland unit: Figure _I _ Estimated size / '-/0 a c r t2 S SUMMARY OF RA TING Category based on FUNCTIONS provided by wetland I_ II_l_ Ill_ IV Score for Water Quality Functions / 'f ate ,ory II = Score 51-69 Category I = core 30-50 Category IV = Score < 30 Score for Hydrologic Functions ;:; t, Score for Habitat Functions ;;.. I IP====;\ TOT AL score fo1· Functions (o I I=====!! Category based on SPECIAL CHARACTERISTICS of wetland I_ II_ Does not Apply X Final c atcgory (,h,o,eth, "l,ighHI" ~"''" from ,h,,.) 1 , r 1 Summarv of basic information about the wetland unit Estuarine Natural Herita!!e Wetland Bo!! Mature Forest Old Growth Forest Coastal La!!oon Interdunal None of the above Wetland Rating Form -westem Washington version 2 To be used with Ecology Publication 04-06-025 Denressional Riverine 'X Lake-frin!!e Slone Flats Freshwater Tidal Check if unit has multiple D HGM classes oresent August 2004 Wetland name or number Does the wetland unit being rated meet any of the criteria below? Jfyou answer YES to any of the questions below you will need to protect the wetland according to the regulations regarding the special characteristics found in the wetland. For the purposes of this rating system, "documented" means the wetland is on the a ro riate state or federal database. SP2. Has the wetland unit been documented as habitat for any State listed Threatened or Endangered animal species? For the purposes of this rating system, "documented" means the wetland is on the appropriate state database. Note: Wetlands with State listed plant species are cate orized as Cate or I Natural Herita e Wetlands see . 19 of data f01m . SP3. Does the wetland unit contain individuals of Priority species listed by the WDFW for the state? SP4. Does the wetland unit have a local significance in addition to its functions? For example, the wetland has been identified in the Shoreline Master Program, the Critical Areas Ordinance, or in a local management plan as having special significance. To complete the next part of the data sheet you will need to determine the Hvdrogeomorphic Class of the wetland being rated. X: The hydrogeomorphic classification groups wetlands into those that function in similar ways. This simplifies the questions needed to answer how well the wetland functions. The Hydrogeomorphic Class of a wetland can be determined using the key below. Seep. 24 for more detailed instructions on classifying wetlands. Wetland Rating Forni -western Washington 2 version 2 Updated with new WOFW definitions Oct. 2008 August 2004 I I I I I fi II I I I I I I I I I I I I I I I I I I I I I I I I I Wetland name or number Classification of Wetland Units in Western Washington 1. Are the water levels in the entire unit usually controlled by tides (i.e. except during floods)? & go to 2 YES -the wetland class is Tidal Fl'inge If yes, is the salinity of the water during periods of annual low flow below 0.5 ppt (parts per thousand)? YES -Freshwater Tidal Fringe NO -Saltwater Tidal Fringe (Estuarine) {( your wetland can be classified as a Freshwater Tidal Fringe use the forms for Rivedne wetlands. !fit is Saltwater Tidal Fringe it is rated as an Estuarine wetland. Wetlands that were called estuarine in the first and second editions of the rating system are called Salt Water Tidal Fringe in the Hydrogeomorphic Classification. Estuarine wetlands were categorized separately in the earlier editions, and this separation is being kept in this revision. To maintain consistency between editions, the term "Estuarine" wetland is kept. Please note, however, that the characteristics that define Category I and II estuarine wetlands have changed (seep. ). 2. The entire wetland unit is flat and precipitation is the only source (>90%) of water to it. Groundwater and surface water runoff are NOT sources of water to the unit. ~ go to 3 YES -The wetland class is Flats If your wetland can be classified as a "Flats" wetland, use the form for Depressional wetlands. 3. Does the entire wetland unit meet both of the following criteria? _The vegetated part of the wetland is on the shores ofa body ofpennanent open water (without any vegetation on the surface) at least 20 acres (8 ha) in size; __ At least 30% of the open water area is deeper than 6.6 ft (2 m)? §-goto 4 YES -The wetland class is Lake-fringe (Lacustrine Fringe) 4. Does the entire wetland unit meet all of the following criteria? __ The wetland is on a slope (slope can be very gradual), __ The water flows through the wetland in one direction (unidirectional) and usually comes from seeps. It may flow subsurface, as sheettlow, or in a swale without distinct banks. __ The water leaves the wetland without being impounded? NOTE: Sw:face water does not pond in these type of wetlands except occasionally in very small and shallow depressions or behind hummocks ( depressions are usually <3/i diameter and less than 1 foot deep). @-go to 5 YES -The wetland class is Slope Wetland Rating Form -western Washington 3 version 2 Updated with new WDFW definitions Oct. 2008 August 2004 Welland name or number 5. Does the entire wetland unit meet all of the following criteria? -2{_ The unit is in a valley, or stream channel, where it gets inundated by overbank flooding from that stream or river ~ The overbank flooding occurs at least once every two years. NOTE: The riverine unit can contain depressions that are filled with water when the river is not flooding. . NO -go to 6 @-The wetland class is Riverine 6. Is the entire wetland unit in a topographic depression in which water ponds, or is saturated to the surface, at some time during the year. This means that any outlet, if present. is higher than the interior of the wetland. NO -go to 7 YES -The wetland class is Depressional 7. Is the entire wetland unit located in a very flat area with no obvious depression and no overbank flooding. The unit does not pond surface water more than a few inches. The unit seems to be maintained by high groundwater in the area. The wetland may be ditched, but has no obvious natural outlet. NO -go to 8 YES -The wetland class is Depression al 8. Your wetland unit seems to be difficult to classify and probably contains several different HOM clases. For example, seeps at the base of a slope may grade into a riverine floodplain, or a small stream within a depressional wetland has a zone of flooding along its sides. GO BACK AND IDENTIFY WHICH OF THE HYDROLOGIC REGIMES DESCRIBED IN QUESTIONS 1-7 APPLY TO DIFFERENT AREAS IN THE UNIT (make a rough sketch to help you decide). Use the following table to identify the appropriate class to use for the rating system if you have several HOM classes present within your wetland. NOTE: Use this table only if the class that is recommended in the second column represents I 0% or more of the total area of the wetland unit being rated. If the area of the class listed in column 2 is less than I 0% of the unit; classify the wetland using the class that represents more than 90% of the total area. IfIJ1JvJtr;1a~$."¢Wi/wltiiWtlfif'iJQtUfl',WiJJHmu~tr1'ki1itlt1:tirtifflt{f~'X:~ rWlH«Mt1tt1s:1m1/ils1rm,JRqZ/'iftJ Slooe + Riverine Riverine Slope+ Deoressional Depressional Slope+ Lake-fringe Lake-fringe Depressional + Riverine along stream within boundary Depressional Depressional + Lake-fringe Deoressional Salt Water Tidal Fringe and any other class of freshwater Treat as ESTUARINE under wetland wetlands with special characteristics If you are unable still to determine which of the above criteria apply to your wetland, or if you have more than 2 HGM classes within a wetland boundary, classify the wetland as Depressional for the rating. Wetland Rating Fom1 -western Washington 4 version 2 Updated with new WDFW definitions Oct. 2008 August2004 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Wetland name or number D D D D D D D 1. Does the wetland unit have the potential to improve water quality? (see p.38) D 1.1 Characteristics of surface water flows out of the wetland: Figure_ Unit is a depression with no surface water leaving it (no outlet) points= 3 Unit has an intermittently flowing, OR highly constricted permanently tlowing outlet points= 2 Unit has an unconstricted, or slightly constricted, surface outlet (permanently flowing) points= I Unit is a "flat" depression (Q. 7 on key), or in the Flats class, with permanent surface outflow and no obvious natnrnl outlet and/or outlet is a man-made ditch points= I (If ditch is not permanently flowing treat unit as "intern,iflem/y flowing'') Provide photo or drawina S 1.2 The soil 2 inches below the surface (or duff layer) is clay or organic (use NRCS definitions) YES NO points= 4 ooints = 0 D 1.3 Characteristics of persistent vegetation (emergent, shrub, and/or forest Cowardin class) Figure_ Wetland has persistent, ungrazed, vegetation>= 95% of area points= 5 Wetland has persistent, ungrazed, vegetation>= 1/2 of area points= 3 Wetland has persistent, ungrazed vegetation > = I /l O of area points = I Wetland has persistent, ungrazed vegetation <1/10 of area points= 0 Mao of Cowardin veqetation classes D 1.4 Characteristics of seasonal ponding or inundation. 111is is the area of the wetland unit that is ponded for at least 2 months, but dries out sometime during the year. Do not count the area that is permanently ponded. Estimate area as the average condition 5 our of JO yrs. Area seasonally ponded is > Y, total area of wetland Area seasonally ponded is > ,4 total area of wetland Area seasonally ponded is < ,4 total area of wetland poims = 4 points= 2 points= 0 Figure_ Mao of Hvdrooeriods r------------------------~=~-~~~~~-------- Total fo1· D 1 Add the points in the boxes above I I ~-+------------------------------------~-----D D D 2. Docs the wetland unit have the opportunity to improve water quality? Answer YES if you know or believe there are pollutants in groundwater or surface water coming into the wetland that would otherwise reduce water quality in streams, lakes or groundwater downgradient from the wetland. Note which of the following conditions provide the sources of pollutants. A unit may have pollutants coming.from several sources, but any single source would qualify as opportunity. Grazing in the wetland or within I 50 fl Untreated stormwater discharges to wetland Tilled fields or orchards within 150 ft of wetland A stream or culvert discharges into wetland that drains developed areas, residential areas, farmed fields, roads, or clear-cut logging Residential, urban areas, golf courses are within 150 It of wetland Wetland is fed by groundwater high in phosphorus or nitrogen Other ________________ _ YES multiplier is 2 NO multiplier is 1 TOTAL-Wate.-Quality Functions Multiply the score from DI by 02 Add score to table on p, 1 (seep. 44) multiplier D Wetland Rating Form -western Washington 5 version 2 Updated with new WDFW definitions Oct. 2008 August 2004 Wetland name or number :~·· ,;:·t;Ci:Ji~;ie'.f&!Jt§JKiI111n~ltliili ' · , ' • "OGIGIEUNG:PI@N . ~.-Xl.i•.~::.'.>1·,;~r,_f~1,}0;;:ii.>i;J',,U.1j,fo;¥:,.,,~~,;, ·n,t~j,',/.oJ,t•ft,lJ~;t:;, .xe uce1flq~din~/i11i'cl(&tf~ijifk . "'iidiitici'i) D D D D 3. Does the wetland unit have the potential to reduce flooding and erosion? D 3.1 Characteristics of surface water flows out of the wetland unit Unit is a depression with no surface water leaving it (no outlet) points= 4 Unit has an intermittently flowing, OR highly constricted permanently flowing outlet poin~, = 2 Unit is a "flat" depression (Q. 7 on key), or in the Flats class, with permanent surface outflow and no obvious natural outlet and/or outlet is a man-made ditch points= I (ff ditch is not permanent{v flowing treat unit a.ff "lntermittent~v jlowh1g ") Unit has an unconstricted, or slight! constricted, surface outlet ermanent/ , owin ) oints = 0 D 3.2 Depth of storage during wet periods Estimate the height of ponding above the bottom of the outlet. For units with no outlet measure from the swface of permanent water or deepest part (if d1y). Marks of ponding are 3 ft or more above the surface or bottom of outlet points = 7 The wetland is a "headwater" wetland" points = 5 Marks of ponding between 2 ft to < 3 ft from surface or bottom of outlet points = 5 Marks are at least 0.5 ft to< 2 ft from surface or bottom of outlet points= 3 Unit is flat (yes to Q. 2 or Q. 7 on key) but has small depressions on the surface that trap water points = I Marks of ondin less than 0.5 ft oints = 0 D 3 .3 Contribution of wetland unit to storage in the watershed Estimate the ratio of the area of upstream basin contributing surface water to the wetland to the area of the wetland unit itse/f The area of the basin is less than 10 times the area of unit The area of the basin is IO to I 00 times the area of the unit The area of the basin is more than 100 times the area of the unit points= 5 points= 3 points= 0 (see p.46) Entire unit is in the FLA TS class oints = 5 ~==~=======~=----------------~==~~~-----Total for D 3 Add the points in the boxes above D ~-~----------------------------------'1-----D D 4. Docs the wetland unit have the opportunity to reduce flooding and erosion? D Answer YES if the unit is in a location in the watershed where the flood storage, or reduction in water velocity, it provides helps protect downstream property and aquatic resources from flooding or excessive and/or erosive flows. Answer NO if the water coming into the wetland is controlled by a stmcture such as flood gate, tide gate, flap valve, reservoir etc. OR you estimate that more than 90% of the water in the wetland is from groundwater in areas where damaging groundwater flooding does not occur. Note which of the following indicators of opportunity apply. Wetland is in a headwater of a river or stream that has flooding problems Wetland drains to a river or stream that has flooding problems Wetland has no outlet and impounds surface mnoff water that might othe,wise flow into a river or stream that has flooding problems -Other _______________ _ YES multi lier is 2 NO multi lier is I TOT AL -Hydrologic Functions Multiply the score from D 3 by D 4 Add score to table on p. 1 Wetland Rating Form -western Washington 6 version 2 Updated with new WDFW definitions Oct 2008 August 2004 (seep. 49) multiplier D I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Wetland name or number R R R R 1. Does the wetland unit have the potential to improve water quality? R 1.1 Area of surface depressions within the riverine wetland that can trap sediments during a flooding event: 1,<Ja+ pt' S-/1,( e ,:;;(12/l< .s Depressions cover >3/4 area of wetland a.fl. ti.lrrws+ Q..IJ2.. points= 8 Depressions cover> 1/2 area of wetland ~rtS:Sctf'() S ~ If depressions > 'h of area of unit draw polygons on aerial photo or map Depressions present but cover < l /2 area of wetland points = 2 No deoressions oresent points = 0 R 1.2 Characteristics of the vegetation in the unit (urcus with >90% cover at person height): Trees or shrubs > 2/3 the area of the unit points = 8 Trees or shrubs> 1/3 area of the unit points= 6 Ungrazed, herbaceous plants > 2/3 area of unit !)Dints = 6 (see p.52) Figurej_ 4 Flgure.eL Ungrazed herbaceous plants> 1/3 area ofunit ~ints = 2) Trees, shrubs, and ungrazed herbaceous < 1/3 area of unit points -0 3 Aerial photo or mao showinq noi""Ons of different veoetation tvoes ~-~~~~=~~~~~~~~=~~~~~~~~~E~-------~-----R Add the points in the boxes above 7 ~-~-----------------------------------4-----(see p.53) R R R 2. Docs the wetland unit have the opportunity to improve water quality? Answer YES if you know or believe there are pollutants in groundwater or surface water coming into the wetland that would otherwise reduce water quality in streams, lakes or groundwater downgradient from the wetland? Note which ofthefo/lowing conditions provide the sources of pollutants. A unit may have pollutants coming.from several sources, but any single source would qiwl/fj, as opportunity. X-Grazing in the wetland or within 150ft X Untreated stonnwater discharges to wetland Tilled fields or orchards within 150 feet of wetland X A stream or culvert discharges into wetland that drains developed areas, residential areas, fanned fields, roads, or clear-cul logging ~ Residential, urban areas, golf courses are within 1 SO fl of wetland ~ The river or stream linked to the wetland has a contributing basin where human activities have raised levels of sediment, toxic compounds or nutrients in the river water above standards for water quality ~ (.( M. 'L on .30 a{,r) I 1S+ Other -h>r futd w/ 1 /:.rt>" @ multiplier is 2 NO multiplier is 1 TOTAL -Water Quality l•unctions Multiply the score from R 1 by R 2 Ad,I score to table on D, 1 Comments Wetland Rating Form -western Washington 7 version 2 Updated with new WDFW definitions Oct. 2008 August 2004 multiplier ;i. / 'f Wetland name or number R R R 3.1 Characteristics of the overbank storage the unit provides: Estimate the average width of the wetland unit perpendicular to the direction of the flow and the width of the stream or river channel (distance between banks). Calculaie the ratio: ( average width qf unit)/( average width o.fstream between b~a::,n:,,k,,.s"---.... If the ratio is more than 20 S-1-rt l'Yl _ l2.J'+ oints = 9 If the ratio is between IO -20 a; • "-s = 6 If the ratio is 5 -<IO kJa.+l"-nol =-"-,3oof.,_ If the ratio is I -<5 If the ratio is < I R 3.2 Characteristics of vegetation that slow down water velocities during floods: Treat large woody debris as "forest or shrub". Choose the points appropriate.for the best description. (polygons need to have >90% cover at person height NOT Cowardin classes): Forest or shrub for> I /3 area OR herbaceous plants > 2/3 area points = 7 Forest or shrub for> 1/10 area OR herbaceous plants> 1/3 area (points=}:) Vegetation does not meet above criteria pomts -O (see p.54) Figure Figure_ Aerial hoto or ma ol ons of different ve elation t es ~-~---------====~~==================-1-----R Add the points in the boxes above / 3 r-----------------------------------------R R R 4. Does the wetland unit have the opportunity to reduce flooding and erosion? Answer YES if the unit is in a location in the watershed where the flood storage, or reduction in water velocity, it provides helps protect downstream property and aquatic resources from flooding or excessive and/or erosive flows. Note which qfthe.following conditions apply. -2' There are human stmctures and activities downstream (roads, buildings, bridges, 'l( fanns) that can be damaged by flooding. There are natural resources downstream ( e.g. salmon redds) that can be damaged by flooding Cl,.1rioo ll-Sf'IWl~ l'\R.M Ul Wc;sh, Other ________________ _ (Answer NO if the major source q( water to the wetland is controlled by a resen,oir or the d is tidal fringe along the sides q( a dike) ES multiplier is 2 NO multiplier is 1 Comments TOT AL -Hydrologic Functions Multiply the score from R 3 by R 4 Add score to table 011 p. I Wetland Rating Fonn -western Washington 8 version 2 Updated with new WOFW definitions Oct. 2008 August2004 (see p.57) multiplier [I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Wetland name or number L L I. Does the wetland unit have the potential to improve water quality? (see p.59) L L L L 1.1 Average width of vegetation along the lakeshore (use polygons 1if'Cowardin c/asse;): Figure_ Vegetation is more than 33ft (!Om) wide points= 6 Vegetation is more than 16 (Sm) wide and <33ft points= 3 Vegetation is more than 6ft (2m) wide and < 16 ft points = I Vegetation is less than 6 ft wide points = 0 Mao of Cowardin classes with widths marked L 1.2 Characteristics of the vegetation in the wetland: choose the 11ppropriate description Figure_ that results in the highest points, and do not include 1my open water in your estimate of coverage. The herbaceous plants can be either the dominant form or as an understory in a shrub or.forest community. 111ese are not Cowardin classes. Area of Cover is total cover in the unit, but it can be in patches. NOTE· Herbaceous does not include aquatic bed. Cover of herbaceous plants is >90% of the vegetated area points = 6 Cover of herbaceous plants is > 2/3 of the vegetated area points = 4 Cover of herbaceous plants is> 1/3 of the vegetated area points= 3 Other vegetation that is not aquatic bed or herbaceous covers > 2/3 unit points= 3 Other vegetation that is not aquatic bed in> 1/3 vegetated area points= 1 Aquatic bed vegetation and open water cover > 2/3 of the unit points = 0 Mao with oolvnons of different veaetation tvnes ~--------------~=================-~-----Add the points in the boxes above ~-~-------------------------------------f-----L 2. Does the wetland have the opp01·tu11ity to improve water quality? (see p.61) L L Answer YES if you know or believe there are pollutants in the lake water, or polluted surface water flowing through the unit to the lake. Note which of the following conditions provide the sources ofpollutants. A unit may ltave pollutants coming from several sources, but any single source would qualify (IS opportunity. Wetland is along the shores of a lake or reservoir that does not meet water quality standards -Grazing in the wetland or within 150ft Polluted water discharges to wetland along upland edge Tilled fields or orchards within 150 feet of wetland Residential or urban areas are within 150 ft of wetland Parks with grassy areas that are maintained, ballfields, golf courses (all within 150 ft. of lake shore) Power boats with gasoline or diesel engines use the lake -Other ----------------- YES multiplier is 2 NO multiplier is 1 TOTAL-Water Quality Functions Multiply the score from L1 by L2 Atl<I score to table 011 o. 1 Comments Wetland Rating Form -western Washington 9 version 2 Updated with new WDFW definitions Oct. 2008 Augllst 2004 multiplier D Wetland name or number L 3. Does the wetland unit have the potential to reduce shoreline erosion? L 3 Distance along shore and average width ofCowardin classes along the lakeshore (do Figure_ not include aquatic bed): (choose the highest scoring description that matches conditions in the wetland) > 'X of distance is shrubs or forest at least 33 ft (I Om) wide points; 6 > 'X of distance is shrubs or forest at least 6 ft. (2 111) wide points ; 4 > !4 distance is shrubs or forest at least 33 ft (1 Om) wide points; 4 Vegetation is at least 6 ft (2m) wide (any type except aquatic bed) points; 2 Vegetation is less than 6 ft (2111) wide (any type except aquatic bed) points; 0 Aerial hoto or ma with Cowardin ve elation classes ~-----------~===~~======~=====~------- L Record the points from the box above ~---------------------------------------L L 4. Docs the wetland unit have the opportunity to reduce erosion? (see p.63) Are there features along the shore that will be impacted if the shoreline erodes? Note which of the following conditions apply. There are human structures and activities along the upland edge of the wetland (buildings, fields) that can be damaged by erosion. There are undisturbed natural resources along the upland edge of the wetland (e.g. mature forests other wetlands) than can be damaged by shoreline erosion Other multiplier YES multiplier is 2 NO multiplier is 1 L TOTAL -Hydrologic Functions Multiply the score from L 3 by L 4 Add score to table 011 p. 1 Comments Wetland Rating Fom1-westcm Washington 10 August 2004 version 2 Updated with new WDFW definitions Oct. 2008 D I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Wetland name or number s s s s s S 1. Docs the wetland unit have the potential to improve water quality? S I .1 Characteristics of average slope of unit: Slope isl% or less (a 1% slope has a I foot vertical drop in elevation for eve1y JOO Ji horizontal distance) points= 3 Slope is I% -2% points = 2 Slope is 2% -5% points = l Slope is greater than 5% points= 0 S 1.2 The soil 2 inches below the surface (or duff layer) is clay or organic (use NRCS definitions) YES = 3 points NO = 0 points S 1.3 Characteristics of the vegetation in the wetland that trap sediments and pollutants: Choose the points appropriate.for the description that best.fits the vegetation in the wetland. Dense vegetation means you have trouble seeing the soil s111face (> 7 5% cove,), and uncut means not grazed or mowed and plants are higher than 6 inches. Dense, uncut, herbaceous vegetation> 90% of the wetland area points= 6 Dense, uncut, herbaceous vegetation > 1 /2 of area points = 3 Dense, woody, vegetation> Y, of area points= 2 Dense, uncut, herbaceous vegetation > I /4 of area points = I Does not meet any of the criteria above for vegetation points = 0 Aerial ohoto or mac with veaetation oolvnons Total for S l Add the points in the boxes above (see p.64) Figure_ .-----. ~--------------------------------------,-----5 s S 2, Does the wetland unit have the opportunity to improve water quality? Answer YES if you know or believe there are pollutants in groundwater or surface water coming into the wetland that would otherwise reduce water quality in streams, lakes or groundwater downgradient from the wetland. Note which of the fa/lowing conditions provide the sources ofpollutants. A unit may have pollutants coming.from several sources, but any single source would qualify as opportunity. Grazing in the wetland or within 150ft Untreated stonnwater discharges to wetland Tilled fields, logging, or orchards within 150 feet of wetland Residential, urban areas, or golf courses are within 150 ft upslope of wetland Other ----------------- YES multiplier is 2 NO multiplier is l TOTAL -Water Quality Functions Multiply the score from S 1 by S2 Atld score to table on p, 1 Comments Wetland Raling Form -western Washington 11 version 2 Updated with new WDFW definitions Oct. 2008 August 2004 (see p.67) multiplier Wetland name or number s s S 3. Does the wetland unit have the potential to reduce flooding and stream erosion? S 3.1 Characteristics of vegetation that reduce the velocity of surface flows during stonns. Choose the points appropriate for the description that best.fit conditions in the wetland. (stems o_f plants should be thick enough (usually > I /8in), or dense enough, to remain erect during su~face flows) Dense, uncut, rigid vegetation covers > 90% of the area of the wetland. Dense, uncut, rigid vegetation > 1/2 area of wetland Dense, uncut, rigid vegetation > 1/4 area More than 1/4 of area is grazed, mowed, tilled or vegetation is points= 6 points= 3 points= I not ri id oints = 0 S 3 .2 Characteristics of slope wetland that holds back small amounts of flood flows: The slope wetland has small surface depressions that can retain water over at least I 0% of its area. YES points = 2 (see p.68) l'J() oints =O ~----------------------~~-~=~~-----1-----S Add the points in the boxes above ~-+----------------------------------"'1-----s S 4. Does the wetland have the opportunity to reduce flooding and erosion? s Is the wetland in a landscape position where the reduction in water velocity it provides helps protect downstream property and aquatic resources from flooding or excessive and/or erosive flows? Note which of the following conditions apply. Wetland has surface runoff that drains to a river or stream that has flooding problems ()ther ________________ _ (Answer NO /(the major source of water is controlled by a resen1oir (e.g. wetland is a seep that is on the downstream side of a dam) YES multi lier is 2 NO multi lier is 1 Comments TOT AL -Hydrologic Functions Multiply the score from S 3 by S 4 Add scol'e to table on p. I Wetland Rating Form-western Washington 12 August 2004 version 2 Updated with new WDFW definitions Oct. 2008 (seep. 70) multiplier D I [I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Wetland name or number H I. Does the wetland unit have the potential to provide habitat for many species? H 1.1 Vegetation structure (seep. 72) Check the types of vegetation classes present (as defined by Cowardin)-Size threshold for each class is '4 acre or more than 10% ofthe area /(unit is smaller than 2.5 acres. __ Aquatic bed -'L..Emergent plants v Scrub/shrub (areas where slu·ubs have >30% cover) .7 Forested (areas where trees have >30% cover) If the unit has ".forested class check if __ The forested class has 3 out of 5 strata (canopy, sub-canopy, slu-ubs, herbaceous, moss/ground-cover) that each cover 20% within the forested polygon Add the 1111111ber of vegetation structures that qualify. {/you have: Map of Cowardtn vegetation classes H 1.2. Hydroperiods (seep. 73) 4 shuctures or more 3 structures 2 structures l structure points= 4 (!§"ints = V points= I points= 0 Check the lypes of water regimes (hydroperiods) present within the wetland. The waler regime has to cover more than I 0% of the wetland or '4 acre to count. (see text for descriptions of hydroperiods) ~ __ Permanently flooded or inundated 4 or more types present _x_Seasonally flooded or inundated 3 types present pomts = 2 --2S.__ Occasionally flooded or inundated 2 types present point= I points= 0 --1'.:_Saturated only I type present ~ Permanently flowing stream or river in, or adjacent to, the wetland __ Seasonally flowing stream in, or adjacent to, the wetland __ L"ke-ft'i11ge wet/1111d = 2 points __ Fres/,,v(lter tit/(1/ wetl1111d = 2 points Map of hydroperiods I-! 1.3. Richness of Plant Species (seep. 75) Count the number of plant species in the wetland that cover at least IO ft2. (different patches of the same species can be combined to meet the size threshold) Yo11 do not have to name the JJJecies. Do not include Eurasian Mi/foil, reed cana1ygrass, purple /oosestr/(e, If you counted: ~ List species below if'you want to: ~s Ch''':! Trt.t s l'U o.J-c./J/.. < 5 species .5c.o..w,is wl /low h,,..,. 8/t1c1C.fJ4 rr1 ;:1,1at1+ 11.orst!:iz:,,; I SI+-"'-"'-W i /l O W f"4> S S jo-/+ ('l,18 1-) u-u..p 1 "~ ~""#' w-f' pet5-IW l ~ ,.-,, s5 • s S /m,a VI S ed 9 e... do~s spw.Lu. ora~ri asn ~o(() Pw.+.-(A.1..i-n,3<,1.. ,ed. 0 ,sa.rd.oetvood r :i:.f\tU.tU'\ ~ll.AJY\ S~tt spruc..Q. ~s -nr PtA.C.-t+i, w1 /lo0 fac.t-hc. runtoC11Lk( Canadian Thistle points= 2 points= I points= 0 Figure..,;;,_ Figurej_ Welland Raling Form-western Washington 13 Total for page _7_:.__ August 2004 version 2 Updated with new WDFW definitions Oct. 2008 Wetland name or number H 1.4. Interspersion of habitats (.veep. 76) Decide from the diagrams below whether interspersion between Cowardin vegetation classes ( described in H 1.1 ), or the classes and unvegetated areas ( can include open water or mudflats) is high, medium, low, or none. C) ·~· None = 0 points Low= l point Moderate= 2 points ~ ,, High = 3 points [riparian braided channels) NOTE: If you have four or more classes or three vegetation classes and open water the ratin is alwa s "hi h". Use map of Coward in vegetation classes H 1.5. Special Habitat Features: (seep. 77) Check the habitat features that are present in the wetland. The number of checks is the number of points you put into the next column. _i_Large, downed, woody debris within the wetland (>4in. diameter and 6 ft long). _{_Standing snags (diameter at the bottom> 4 inches) in the wetland _L Undercut banks are present for at least 6.6 ft (2m) and/or overhanging vegetation extends al least 3.3 ft (Im) over a stream (or ditch) in, or contiguous with the unit, for at least 33 ft (!Om) __ Stable steep banks of fine material that might be used by beaver or muskrat for denning (>30degree slope) OR signs of recent beaver activity are present (cut shrubs or trees that have not yet turned grey/brown) __ At least Y.. acre of thin-stemmed persistent vegetation or woody branches are present in areas that are pennanently or seasonally inundated.(structures for egg-laying by amphibians) __ Invasive plants cover less than 25% of the wetland area in each stratum of plants NOTE: The 20% stated in early printings of the manual on page 78 is an erro1·. igure 3 r------------------------------------,.---- H 1. TOTAL Score -potential for providing habitat I ' 12.. I I Add the scores rom HJ.I, Hl.2, Hl.3, HJ.4, 111.5 ~---------------~~~--=~-~~~~~-=-~=~~------ Comments Wetland Rating Fonn -western Washington 14 August2004 version 2 Updated with new WDFW definitions Oct. 2008 I I II I I I I I I I I I [I I I I I I I I I I I I I I I I I I I I I Wetland name or number H 2. Does the wetland unit have the opportunity to provide habitat for many species? H 2.1 Buffers (seep. 80) Choose the description that best represents condition ofb11[ler of wetland unit. ltie highest scoring criterion that applies to the wetland is to be used in the rating. See text.for definition of "undisturbed. " -I 00 m (330ft) of relatively undisturbed vegetated areas, rocky areas, or open water >95% of circumference. No structures are within the undisturbed pa11 of buffer. (relatively undisturbed also means no-grazing, no landscaping, no daily human use) Points= 5 -I 00 m (330 ft) of relatively undisturbed vegetated areas, rocky areas, or open water > 50% circumference. Points = 4 -50 m (170ft) of relatively undisturbed vegetated areas, rocky areas, or open water >95% circumference. Points = 4 -l 00 m (330ft) of relatively undisturbed vegetated areas, rocky areas, or open water> 25% circumference, . Points = 3 -50 m (170ft) of relatively undisturbed vegetated areas, rocky areas, or open water for> 50% circumference. Points = 3 If buffer docs not meet any of the criteria above -No paved areas (except paved trails) or buildings within 25 111 (80ft) of wetland> 95% circumference. Light to moderate grazing, or lawns are OK. Points = 2 2( No paved areas or buildings within 50m of wetland for >50% circumference. Light to moderate grazing, or lawns are OK. Points = 2 -Heavy grazing in buffer. Points= I -Vegetated buffers are <2m wide (6.6ft) for more than 95% of the circumference (e.g. tilled fields, paving, basalt bedrock extend to edge of wetland Points= 0. -Buffer does not meet any of the criteria above. Points= I Aerial photo showinq buffers I-I 2.2 Corridors and Connections (seep. 81) H 2.2. l ls the wetland pa1t of a relatively undisturbed and unbroken vegetated corridor ( either riparian or upland) that is at least 150 ft wide, has at least 30% cover of shrubs, forest or native undisturbed prairie, that connects to estuaries, other wetlands or undisturbed uplands that are at least 250 acres in size? (dams in riparian corridors, heavily used gravel roads, paved roads, are considered breaks in the corridor)--, YES= 4 points (go to fl 2.3) (2::.9)= go to H 2.2.2 H 2.2.2 Is the wetland pa11 of a relatively undisturbed and unbroken vegetated corridor (either riparian or upland) that is at least 50ft wide, has at least 30% cover of shrubs or forest, and connects to estuaries, other wetlands or undisturbed uplands that are at least 25 acres in size? OR a Lake-fringe wetland, if it does not have an undisturbed corridor as in the question above? YES= 2 points (go to fl 2.3) @= H 2.2.3 H 2.2.3 Is the wetland: within 5 mi (8km) of a brackish or salt water estuary OR within 3 mi of a large field or pasture (>40 acres) OR):t withi~i of a lake greater than 20 acres? (YES r l point NO = 0 noints Figure _J_ Total for page 3 Wetland Rating Form -western Washington 15 August 2004 version 2 Updated with new WDFW definitions Oct. 2008 Wetland name or number H 2.3 Near or adjacent to other prioritv habitats listed bv WDFW (see 11ew a11d complete descriptions o.fWDFW priority lrabitats, and tfte counties i11 wlric/r t/tey ca11 be.fo1111d, i11 tfte PHS report /tttp:llwd(w. wa.gov//,ah/pftslist.f1t111) Which of the following priority habitats arc within 330ft {IOOm) of the wetland unit? NOTE: the connections do not have to be relatively undisturbed. __ Aspen Stands: Pure or mixed stands of aspen greater than 0.4 ha (I acre). __ Biodiversity Areas and Corridors: Areas of habitat that are relatively important to various species of native fish and wildlife (full descriptions in WDFW PHS report p. 152). _Herbaceous Balds: Variable size patches of 1,,i·ass and forbs on shallow soils over bedrock. __ Old-growth/Mature forests: (Old-growth west of Cascade crest) Stands of at least 2 tree species, fotming a multi-layered canopy with occasional small openings; with at least 20 trees/ha (8 trees/acre)> 81 cm (32 in) dbh or> 200 years of age. (Mature forests) Stands with average diameters exceeding 53 cm (21 in) dbh; crown cover may be less that I 00%; crown cover may be less that I 00%; decay, decadence, numbers of snags, and quantity of large downed material is generally less than that found in old-growth; 80 -200 years old west of the Cascade crest. __ Oregon white Oak: Woodlands Stands of pure oak or oak/conifer associations where canopy coverage of the oak component is important ((ufl descriptions in WDFW PHS report p. 158). LRiparian: The area adjacent to aquatic systems with flowing water that contains elements of both aquatic and terrestrial ecosystems which mutually influence each other. __ Westside Prairies: Herbaceous, non-forested plant communities that can either take the form of a dry prairie or a wet prairie (full descriptions in WDFW PHS report p. 161). _i_1nstream: The combination of physical, biological, and chemical processes and conditions that interact to provide functional life history requirements for instream fish and wildlife resources. __ Nearshorc: Relatively undisturbed nearshore habitats. These include Coastal Nearshore, Open Coast Nearshore, and Puget Sound Nearshore. (ji11/ descriptions of habitats and the definition of relatively undisturbed are in WDFW report: pp. 167-169 and glossa,y in Appendix A). __ Caves: A naturally occurring cavity, recess, void, or system of interconnected passages under the earth in soils, rock, ice, or other geological fonnations and is large enough to contain a human. _Cliffs: Greater than 7.6 m (25 ft) high and occurring below 5000 ft. __ Talus: Homogenous areas of rock rubble ranging in average size 0.15 -2.0 m (0.5 -6.5 ft), composed of basalt, andesite, and/or sedimentary rock, including riprap slides and mine tailings. May be associated with cliffs. __ Snags and Logs: Trees are considered snags if they are dead or dying and exhibit sufficient decay characteristics to enable cavity excavation/use by wildlife. Priority snags have a diameter at breast height of> 51 cm (20 in) in westem Washington and are> 2 m (6.5 ft) in height. Priority logs are> 30 cm (12 in) in diameter at the largest end, and> 6 m (20 ft) long. If wetland has 3 or more priority habitats = 4 points If wetland has 2 priority habitats~ If wetland has 1 priority habitat = )imiiif" No habitats = 0 points Note: All vegetated wetlands are by d~finition a priority habitat but are not included in this list. Nearbv wetlands are addressed in question H 2.4) Wetland Rating Fonn -western Washington 16 August 2004 version 2 Updated with new WDFW definitions Oct. 2008 I [I I I I I I I I I I I I I I 3 I I I I I I I I I I I I I I I I I I I I I I I Welland name or number H 2.4 Wetland Landscape (choose the 011e description of the landscape around the wetland that best.fits) (seep. 84) There are at least 3 other wetlands within Y, mile, and the connections between them are relatively undisturbed (light grazing between wetlands OK, as is lake shore with some boating, but connections should NOT be bisected by paved roads, fill, fields, or other development. points= 5 The wetland is Lake-fringe on a lake with little disturbance and there are 3 other lake-fringe wetlands within Y, mile points= 5 There are at least 3 other wetlands within Y, mile, BUT the connections between t~:~ disturbed points = The wetland is Lake-fringe on a lake with disturbance and there are 3 other lake-frmge wetland within Y, mile points= 3 There is at least 1 wetland within Y, mile. points= 2 There are no wetlands within Y, mile. points= 0 H 2. TOT AL Score -opportunity for providing habitat Add the scores.from H2.1,H2.2, H2.3, H2.4 TOT AL for H I from page 14 Total Score for Habitat Functions -add the points for H 1, H 2 and record the result on o. 1 Wetland Rating Form -western Washington 17 August 2004 version 2 Updated with new WDFW definitions Oct. 2008 3 -----0 ry I I I ----- I 1-. ----- al I Wetland name or number CATEGORIZATION BASED ON SPECIAL CHARACTERISTICS Please determine if the wetland meets the attributes described below and circle the appropriate answers and Category. Wetland Type · Category Check off any criteria that apply to the wetland. Circle the Category when the avvropriate criteria are met. SC 1.0 Estuarine wetlands (seep. 86) Does the wetland unit meet the following criteria for Estuarine wetlands? -The dominant water regime is tidal, -Vegetated, and -With a salinity greater than 0.5 ppt. NO){_ YES = Go to SC I. I SC 1.1 Is the wetland unit within a National Wildlife Refuge, National Park, National Estuary Reserve, Natural Area Preserve, State Park or Educational, Cat. I Environmental, or Scientific Reserve designated under WAC 332-30-151? YES = Category I /NO)go to SC 1.2 SC 1.2 Is the wetland unit at least I acre in size and meets at least two of the following three conditions? YES = Category I NO = Category JI Cat. I -The wetland is relatively undisturbed (has no diking, ditching, filling, Cat. II cultivation, grazing, and has less than I 0% cover of non-native plant species. If the non-native Spartina spp. are the only species that cover more than 10% of the wetland, then the wetland should be given a dual Dual rating (J/11). The area of Spartina would be rated a Category II while the rating relatively undisturbed upper marsh with native species would be a I/II Category I. Do not, however, exclude the area of Spartina in detennining the size threshold of I acre. -At least ~ of the landward edge of the wetland has a 100 ft buffer of shrub, forest, or un-grazed or un-mowed grassland. -The wetland has at least 2 of the following features: tidal channels, depressions with open water, or contiguous freshwater wetlands. Wetland Rating Fonn -western Washington 18 August2004 version 2 Updated with new WDFW definitions Oct. 2008 fl I I I I I I I Ii m I i I I I I I I I I I I I I I I I I I I I I I I I Wetland name or number SC 2.0 Natural Heritage Wetlands (~·ee p. 87) Natural Heritage wetlands have been identified by the Washington Natural Heritage Program/DNR as either high quality undisturbed wetlands or wetlands that support state Threatened, Endangered, or Sensitive plant species. SC 2. I Is the wetland unit being rated in a Sectionffownship/Range that contains a Natural Heritage wetland? (this question is used to screen out most sites before you need to contact WNHPIDNR) Sff/R information from Appendix D _ or accessed from WNHP/DNR web site 2/2 /'2.0I 0 Closes-+ 1 ~ ,i. ?,N R.S !: 545 YES __ -contact WNHP/DNR (seep. 79) and go to SC 2.2 NO X SC 2.2 Has DNR identified the wetland as a high quality undisturbed wetland or as or as a site with state threatened or endangered plant species? YES= Category I NO )( not a Heritage Wetland SC 3.0 Bogs (seep. 87) Does the wetland unit ( or any part of the unit) meet both the criteria for soils and vegetation in bogs? Use the key below to identify ifthe wetland is a bog. lfyo11 answer yes you will still need to rate the wetland base,/ 011 itsji111ctio11~~ I. Does the unit have organic soil horizons (i.e. layers of organic soil), either peats or mucks, that compose 16 inches or more of the first 32 inches of the soil profile? (See Appendix B for a field key to identify organic soils)? Yes - go to Q. 3 No -go to Q. 2 2. Does the unit have organic soils, either peats or mucks that are less than 16 inches deep over bedrock, or an impermeable hardpan such as clay or volcanic ash, or that are floating on a lake or pond? Yes -go to Q. 3 No -ls not a bog for purpose of rating 3. Does the unit have more than 70% cover of mosses at ground level, AND other plants, if present, consist of the "bog" species listed in Table 3 as a significant component of the vegetation (more than 30% of the total shrub and herbaceous cover consists of species in Table 3)? Yes -Is a bog for purpose of rating No -go to Q. 4 NOTE: If you are uncertain about the extent of mosses in the understory you may substitute that criterion by measuring the pH of the water that seeps into a hole dug at least 16" deep. If the pH is less than 5.0 and the "bog" plant species in Table 3 are present, the wetland is a bog. /. Is the unit forested(> 30% cover) with sitka spruce, subalpine fir, western red cedar, western hemlock, lodgepole pine, quaking aspen, Englemann's spruce, or western white pine, WITH any of the species (or combination of species) on the bog species plant list in Table 3 as a significant component of the ground cover(> 30% coverage of the total shrub/herbaceous cover)? 2. YES= Category l No_0 Is not a bog for purpose of rating Wetland Rating Form -western Washington 19 August 2004 version 2 Updated with new WDFW definitions Oct. 2008 Cat. I Cat. I Wetland name or number SC 4.0 Forested Wetlands (seep. 90) Does the wetland unit have at least I acre of forest that meet one of these criteria for the Department of Fish and Wildlife's forests as priority habitats? {(you answer yes you will still need to rate the wetland based on its.functions. -Old-growth forests: (west of Cascade crest) Stands of at least two tree species, fonning a multi-layered canopy with occasional small openings; with at least 8 trees/acre (20 trees/hectare) that are at least 200 years of age OR have a diameter at breast height (dbh) of 32 inches (8 I cm) or more. NOTE: The criterion for dbh is based on measurements for upland forests. Two-hundred year old trees in wetlands will often have a smaller dbh because their growth rates are often slower. The DFW criterion is and "OR" so old-growth forests do not necessarily have to have trees of this diameter. -Mature forests: (west of the Cascade Crest) Stands where the largest trees arc 80-200 years old OR have average diameters (dbh) exceeding 21 inches (53cm); crown cover may be less that I 00%; decay, decadence, numbers of snags, and quantity of large downed material is generally less than that found in old-growth. YES = Category I NO X not a forested wetland with special characteristics SC 5.0 Wetlands in Coastal Lagoons (seep. 91) Does the wetland meet all of the following criteria ofa wetland in a coastal lagoon? -The wetland lies in a depression adjacent to mminc waters that is wholly or partially separated from marine waters by sandbanks, gravel banks, shingle, or, less frequently, rocks -The lagoon in which the wetland is located contains surface water that is saline or brackish(> 0.5 ppt) during most of the year in at least a portion of the lagoon (needs to be measured near the bottom) YES = Go to SC 5. I NO ...X. not a wetland in a coastal lagoon SC 5. I Does the wetland meets all of the following three conditions? -The wetland is relatively undisturbed (has no diking, ditching, filling, cultivation, grazing), and has less than 20% cover of invasive plant species (see list of invasive species on p. 74). -At least 1,, of the landward edge of the wetland has a I 00 ft buffer of shrub, forest, or un-grazed or un-mowcd grassland. -The wetland is larger than 1/10 acre (4350 square feet) YES = Category I NO = Category II Wetland Rating Form -western Washington 20 August 2004 version 2 Updated with new WDFW definitions Oct. 2008 Cat. I Cat. I Cat. II I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Wetland name or number SC 6.0 Intcrdunal Wetlands (seep. 93) ls the wetland unit west of the 1889 line (also called the Western Boundary of Upland Ownership or WBUO)? YES -go to SC 6.1 NO X not an intcrdunal wetland for rating lfyo11 answer yes you will still 11ee,I to mte the wetland based on its ji111ctio11s. In practical terms that means the following geographic areas: o Long Beach Peninsula-lands west of SR I 03 o Grayland-Westport-lands west of SR 105 o Ocean Shores-Copalis-lands west of SR 115 and SR I 09 SC 6.1 Is the wetland one acre or larger, or is it in a mosaic of wetlands that is once acre or larger? YES = Category II NO -go to SC 6.2 Cat. II SC 6.2 Is the unit between 0.1 and 1 acre, or is it in a mosaic of wetlands that is between 0.1 and I acre? YES = Category III Cat. I II Wetland Rating Form -western Washington 21 version 2 Updated with new WDFW definitions Oct. 2008 August 2004 ---~a;treeK\/~ey~tl~ncr'2cffl9"Ae?r'al-~(~ • • W*' s Legend B l"-cK ot..ct-11"' e. De..pri sst~l'l .s Feet 0 480 960 1,920 U S Fish and Wildlife Service: Conus national wetlands inventory -polygons I~ ;;§ 0 :::, "' ~ 0) '< () .., CD CD ""' < ru -- ru - I I I I I I I I I I I I I I I I I I I WETLAND DETERMINATION DATA FORM -Western Mountains, Valleys, and Coast Region Project Site: Applicant/Owner: lnvestigator(s): May Creek Valley -ONRP King County DNRP Miller, Martin, Clark Landform (hillslope, terrace, etc.): Valley Lat: Subregion (LRR): Soil Map Unit Name: RdC,Bh 47.51495 Are climatic / hydrologic conditions on the site typical for this time of year? City/County: King State: WA Sampling Date: Sampling Point: Section, Township, Range: S2, T23N, R5E 1-21-2010 Soil Pit #1 Local relief (concave, convex, none): flat Slope(%): 0.5 Long: -122.14239 Datum: NWI classification: PEM/PSS Yes No D (If no, explain in Remarks.) Are Vegetation Are Vegetation D, Soil 0. Soil D, Or Hydrology D, significantly disturbed? 0, Or Hydrology 0. naturally problematic? Are "Normal Circumstances" present? Yes 181 No D (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS -Attach site map showing sampling point locations, transects, important features, etc. Hydrophytic Vegetation Present? Yes 181 No D Hydric Soil Present? Yes 181 No D Is the Sampllng Area within a Wetland? Yes 181 No D Wetland Hydrology Present? Yes 181 No D Remarks: SP #1 south of creek just west of barbed wire fence (probably 1"1 property east of 1481 h) -about 30-35 feet south of creek. VEGETATION-Use scientific names o · olants Tree Stratum (Plot Size: 10m) Absolute Dominant Indicator Dominance Test Worksheet: % Cover Species? Status 1. Prunus spp. 30 y FACU Number of Dominant Species That Are 3 (A) 2. OBL, FACW, or FAG: 3. Total Number of Dominant Species Across 4 (B) 4. All Strata: 30 = Total Cover Percent of Dominant Species That Are 75 (NB) Sapling/Shrub Stratum (Plot Size: 10m) OBL, FACW, or FAC: 5. Oemleria cerasifonnis 5 N FACU Prevalence Index worksheet: 6. Salix sitchensis 30 y FACW Total °to Cover of: Multipll bl: 7. Salix scou/eriana 30 y FAG OBL species x1 = 8. FAGW species x2 = 9. FAG species x3 = 65 = Total Cover FAGU species x4 = Herb Stratum (Plot Size: Sm) UPL species x5 = 10. Phalarls arundinacea 30 y FACW Column Totals: (A) (B) 11. Unknown grass 5 N ? Prevalence Index = BIA = 12. Unknown grass Trace N ? Hydrophytic Vegetation Indicators: 13. X Dominance Test is >50% 14. Prevalence Index is ~3.01 15. Morphological Adaptations1 (Provide supporting data in 16. Remarks or on a separate sheet) 17. Wetland Non-Vascular Plants1 18. Problematic Hydrophytic Vegetation1 (Explain) 19. 20. 11ndicators of hydric soil and wetland hydrology must be present, 35 = Total Cover unless disturbed or problematic. Woodl Vine Stratum {Plot Size: ) 1. Rubus procerus Trace N FACU 2. 130 = Total Cover Hydrophytic Vegetation % Bare Ground in Herb Stratum 65 Present? Yes 181 No D Remarks: Starting to see buds. This is a forested/scrub-shrub portion of the wetland along tha stream. US Army Corps of Engineers Western Mountains, Valley, and Coast-Interim Version Project Site: May Creek Valley-DNRP SOIL Samolina Point: #1 Profile Description: (Describe to the depth needed to document the Indicator or confirm the absence of Indicators.) I Depth Matrix Redox Features i (inches) Color (moist) % Color (Moist) % Type 1 Loc2 Texture Remarks ---------0-18" 10YR 2/1 100 Too small color 1 C M clay I I 1Type: C= Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains. 2Location: I Pl=Pore lining, M=Matrix Hydric Soll Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydrlc Solls3: D Histosol (A 1) D Sandy Redox (S5) D 2 cm Muck (A10) D Histic Eplpedon (A2) D Stripped Matrix (S6) D Red Parent Material (TF2) I D Black Histic (A3) D loamy Mucky Mineral (F1) (except MLRA 1) D Other (Explain in Remarks) D Hydrogen Sulfide (A4) D Loamy Greyed Matrix (F2) D Depleted Below Dark Surface (A 11) 181 Depleted Matrix (F3) I D Thick Dark Surface (A 12) D Redox Dark Surface (F6) D Sandy Mucky Mineral (S1) D Depleted Dark Surface (F7) 31ndlcators of hydrophytic vegetation and wetland D Sandy Gleyed Matrix (S4) D Redox Depressions (F8) hydrology must be present, unless disturbed or oroblematic. I Restrictive Layer (If present): Type: Depth (Inches): Hydric Soils Present? Yes 181 No D Remarks: Very uniform matrix, all one horizon within 18 inches. Contains live roots. I I HYDROLOGY I Wetland Hydrology Indicators: Primary Indicators (minimum of one required; check all that apply) Secondary Indicators (2 or more required) 181 Surface Water (A 1) D Water-Stained Leaves (89) D Water-Stained Leaves (89) 181 High Water Table (A2) (except MLRA 1, 2, 4A, and 48) (MLRA 1, 2, 4A, and 4B) I 181 Saturation (A3) D Salt Crust (811) D Drainage Patterns (B 10) 181 Water Marks (B 1) D Aquatic Invertebrates (813) D Dry-Season Water Table (C2) D Sediment Deposits (B2) D Hydrogen Sulfide Odor (C1) D Saturation Visible on Aerial Imagery (C9) D Drift Deposits (83) D Oxidized Rhizospheres along Living Roots (C3) D Geomorphic Position (02) D Algal Mat or Crust (B4) D Presence of Reduced Iron (C4) D Shallow Aquitard (03) D Iron Deposits (85) D Recent Iron Reduction in Tilled Soils (C6) D FAC-Neutral Test (05) D Surface Soil Cracks {86) D Stunted or Stresses Plants (01) {LRR A) D Raised Ant Mounds (06) (LRR A) I D Inundation Visible on Aerial Imagery (87) D Other (Explain in Remarks) D Frost-Heave Hummocks (07) D Sparsely Vegetated Concave Surface (88) Field Observations: Surface Water Present? Yes D No 181 Depth (inches): Water Table Present? Yes 181 No D Depth (inches): 8inches Saturation Present? Yes 181 No D Depth (inches): O inches Wetland Hydrology Present? Yes llll No D (includes capillary fringe) I Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: Remarks: About 35 feet from stream in an area with less reed canarygrass. Some standing water present within about 10 feet. Assuming hydrology would also be present later in the growing season. 0 u US Army Corps of Engineers Western Mountains, Valley, and Coast-Interim Version I I I I I I I I I I I I I I I I I I I WETLAND DETERMINATION DATA FORM -Western Mountains, Valleys, and Coast Region Project Site: ApplicanVOwner: lnvestigator(s): May Creek Valley • ONRP King County DNRP Miller, Martin, Clark City/County: King State: WA Sampling Date: Sampling Point: Section, Township, Range: S2, T23N, RSE 1-21-2010 Soil Pit #2 Landform {hillslope, terrace, etc.): Valley Lat: local relief (concave, convex, none): flat Slope(%): 0.5 Subregion (LRR): 47.51495 Long: -122.14239 Datum: Soil Map Unit Name: RdC,Bh NWI classification: PEM/PSS Are climatic I hydrologic conditions on the site typical for this time of year? Yes No D (If no, explain in Remarks.) Are Vegetation Are Vegetation 0, Soil D, Soil 0, Or Hydrology D. significantly disturbed? D, Or Hydrology D, naturally problematic? Are ·Normal Circumstances" present? Yes 181 No D (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS -Attach site map showing sampling point locations transects important features etc . ' ' Hydrophytic Vegetation Present? Yes D No !il Hydric Soil Present? Yes D No !il Is the Sampling Area within a Wetland? Yes D No !il Wetland Hydrology Present? Yes D No !il Remarks: Too many grasses were present that we could not identify given the time of year for us to feel confident about the vegetation analysis; however, we are comfortable in saying this sample area is not within a wetland because the hydrlc sol/ and hydrology are not present. VEGETATION -Use scientific names of olants Tree Stratum (Plot Size: 10m) Absolute Dominant Indicator Dominance Test Worksheet: % Cover Species? Status 1. None Number of Dominant Species That Are 1 (A) 2. OBL, FACW, or FAC: 3. Total Number of Dominant Species Across 2 (8) 4. All Strata: 0 = Total Cover Percent of Dominant Species That Are 50 (A/8) Sapling/Shrub Stralum (Plot Size: 10m) OBL, FACW, or FAC: 5. Cytisus scoparius (scotch broom) Trace N ? Prevalence Index worksheet: 6. Total % Cover of: Multiply by: 7. OBL species 0 x1 = 0 8. FACW species 15 x2 = 30 9. FAC species 42 x3 = 126 0 = Total Cover FACU species 42 x4 = 168 Herb Stratum (Plot Size: 5 m) UPL species 0 x5 = 0 10. Thistle species Trace N ? Column Totals: 99 (A) 324 (8) 11. Festuca arundinacea 42 y FAG Prevalence Index= BIA= 3.2 12. Datctylis glomerata 42 y FACU Hydrophytlc Vegetation Indicators: 13. Phalaris arundinacea 15 N FACW No Dominance Test is >50% 14. Unknown grasses No Prevalence Index is .::_3.0 1 15. Morphological Adaptations 1 {Provide supporting data in 16. Remarks or on a separate sheet) 17. Wetland Non-Vascular Planls1 18. Problematic Hydrophytic Vegetation1 (Explain) 19. 20. 1 Indicators of hydric soil and wetland hydrology must be present, 99 = Total Cover unless disturbed or problematic. Woody Vine Stratum (Plot Size: 10m) 1. Rubus procerus Trace N FACU 2. 99 = Total Cover Hydrophytic Vegetation % Bare Ground in Herb Stratum 0% Present? Yes D No !il Remarks: US Army Corps of Engineers Western Mountains, Valley, and Coast -Interim Version Project Site: May Creek Valley -DNRP SOIL s p . #2 I amp mo omt: Profile Description: (Describe to the depth needed to document the Indicator or confirm the absence of indicators.) I Depth Matrix Redox Features (inches) Color (moist) % Color (Moist) % Type1 Loc2 Texture Remarks ---------o-8· 7.5YR 2.5/3 100 2.SYR 518 1 C M Sandy loam 8-18" 10YR% 100 Loamy sand Contains large gravels I I 1Type: C= Concentration, D=Deplelion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains. 2Location: PL=Pore Lining, M=Matrix Hydrlc Soll Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric SollsJ: D Histosor (A1) D Sandy Redox (S5) D 2 cm Muck (A10) D Histic Epipedon (A2) D Stripped Matrix (S6) D Red Parent Material (TF2) I D Black Hlstic (A3) D Loamy Mucky Mineral (F1) (except MLRA 1) D Other (Explain in Remarks) D Hydrogen Sulfide (A4) D Loamy Gleyed Matrix (F2) D Depleted Below Dark Surface (A 11) D Depleted Matrix (F3) I D Thick Dark Surface (A12) D Redox Dark Surface (F6) D Sandy Mucky Mineral (S1) D Depleted Dark Surface (F7) 3lndicators of hydrophytic vegetation and wetland D Sandy GI eyed Matrix (S4) D Redox Depressions (F8) hydrology must be present, unless disturbed or oroblematic. I Restrictive Layer (If present): Type: Depth (Inches): Hydric Soils Present? Yes D No 181 Remarks: This soil is dry as a bone and very bright. I About 10 feet north of this soil pit (towards the wetland), another hole has a grayish transition (Gtey1 5/10Y) at 10-11 inches at approximate boundary between reed canarygrass and blackberry. About 5 feet north of this soil pit the color is 2.5Y 5/2 in bottom of the pit. I HYDROLOGY I Wetland Hydrology Indicators: Primary Indicators (minimum of one required; check all that apply) Secondary Indicators (2 or more required) D Surface Water (A 1) D Water-Stained Leaves (89) D Water-Stained Leaves (89) D High Water Table (A2) (except MLRA 1, 2, 4A, and 4B) (MLRA 1, 2, 4A, and 40) D Saturation (A3) D Salt Crust (B 11) D Drainage Patterns (810) D Water Marks (81) D Aquatic Invertebrates (813) D Ory-Season Water Table (C2) D Sediment Deposits (82) D Hydrogen Sulfide Odor (C1) D Saturation Visible on Aerial Imagery (C9) I D Drift Deposits (93) D Oxidized Rhizospheres along Living Roots (C3) D Geomorphic Position (02) D Algal Mat or Crust (84) D Presence of Reduced Iron (C4) D Shallow Aquitard (03) D Iron Deposits (85) D Recent Iron Reduction in TIiied Soils (C6) D FAG-Neutral Test (05) D Surface Soil Cracks (B6) D Stunted or Stresses Plants (01) (LRR A) D Raised Ant Mounds (06) (LRR A) I D Inundation Visible on Aerial Imagery (B7) D Other (Explain in Remarks) D Frost-Heave Hummocks (07) D Sparsely Vegetated Concave Surface (B8) Field Observations: Surface Water Present? Yes D No 181 Depth (inches): Water Table Present? Yes D No 181 Depth (inches): Saturation Present? Yes D No 181 Depth (Inches): Wetland Hydrology Present? Yes D No 181 (includes capillary fringe) I Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: Remarks: No groundwater within 18 inches of surface. I I US Army Corps of Engineers Western Mountains, Valley. and Coast -Interim Version I I I I I I I I I I I I I I I I I I I I WETLAND DETERMINATION DATA FORM -Western Mountains, Valleys, and Coast Region Project Site: ApplicanUOwner: lnvesligator(s): May Creek Valley· DNRP King County DNRP Martin, Clark landform (hillslope, terrace, etc.): Valley Lat: Subregion (LRR): Soil Map Unit Name: RdC,Bh 47.51495 City/County: King State: WA Sampling Date: Sampling Point: Section, Township, Range: S2, T23N, RSE 1-26-2010 Soil Pit #3 Local relief {concave, convex, none): flat Slope(%): 0.5 Long: No -122.14239 Datum: NWI classification: 0 (If no, explain in Remarks.) PEM/PSS Are climatic/ hydrologic conditions on the site typical for this time of year? Yes Are Vegetation 181. Soil D. Or Hydrology 0. significantly disturbed? Are "Normal Circumstances" present? Yes ~ No D Are Vegetation D. Soil D. Or Hydrology D. naturally problematic? (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS -Attach site map showing sampling point locations, transects, important features, etc. Hydrophytic Vegetation Present? Yes 181 No D Hydric Soil Present? Yes 181 No D Is the Sampling Area within a Wetland? Yes 181 No D Wetland Hydrology Present? Yes 181 No D Remarks: Soll Pit #3 Is located on Colasurdo property, just east of the tributary along the access road. Chose this location because there are horses south of the fence. The vegetation In this area Is mowed and grazed. VEGETATION -Use scientific names of olants Tree Stratum {Plot Size: 10m ) 1. None 2. 3. 4. Sapling/Shrub Stratum (Plot Size: 10m) 5. None 6. 7. 8. 9. Herb Stratum (Plot Size: Sm ) 10. Juncus effusus 11. Unknown pasture grasses 12. Ranuncu/us repens 13. Moss species 14. 15. 16. 17. 18. 19. 20. Woody Vine Stratum (Plot Size: ) 1. Rubus procerus 2. % Bare Ground in Herb Stratum Absolute % Cover 0 0 51 42 Trace 5 98 Trace 98 Dominant Species? = Total Cover = Total Cover y y N N = Total Cover N = Total Cover Indicator Status FACW ? FACW ? FACU Dominance Test Worksheet: Number of Dominant Species That Are OBL, FACW, or FAC: Total Number of Dominant Species Across AU Strata: Percent of Dominant Species Thal Are OBL, FACW, or FAC: Prevalence Index worksheet: Total % Cover of: OBL species FACW species ? FAC species FACU species UPL species ? 2 ? Multiply by: x1 = x2 = ? x3 = x4 = x5 = (A) (B) (A/B) Column Totals: (A) (B) Prevalence Index= B/A? Hydrophytic Vegetation Indicators: ? ? Dominance Test is >50% Prevalence 1ndex is ~3.0 1 Morphological Adaptations 1 (Provide supporting data in Remarks or on a separate sheet) Welland Non-Vascular Plants1 Problematic Hydrophytic Vegetation1 (Explain) 11ndicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic. Hydrophytic Vegetation Present? Yes No D Remarks: Vegetation may be marginal, but It Is difficult to detennine because the area is highly disturbed with previous horse use. Some of the dominant grass types cannot be determined due to the season and mowing. Based on the large amount of Juncus effusus, and the obvious Indicators of hydrology and hydric soil we are assuming that the vegetation would be hydric if given an opportunity to naturally grow. US Army Corps of Engineers Western Mountains, Valley, and Coast -Interim Version Project Site: May Creek Valley -DNRP SOIL s am~ linQ Point: #3 Profile Description: (Describe to the depth needed to document the Indicator or confirm the absence of Indicators.) I Depth Matrix Redox Features (inches) Color (moist) % Color (Moist) % Type 1 Loc2 Texture Remarks ---------0-6.5" 5YR 2.5/1 100 Loamy sand Saturated to the surface 6.5-11.5" 10YR 5/4 90 10YR 4/6 10 C M Silty loam I 11.5-16~ 10YR 4/6 100 Silty loam 1Type: C= Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains. 2Location: PL=Pore Lining, M=Matrix I Hydrlc Soil Indicators: (Appllcable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydrlc Solls3: D Histosol (A 1) D Sandy Redox (S5) D 2 cm Muck (A10) D Histic Epipedon (A2) D Stripped Matrix (S6) D Red Parent Material (TF2) I D Black Histic (A3) D loamy Mucky Mineral (F1) (except MLRA 1) D Other (Explain in Remarks) D Hydrogen Sulfide (A4) D Loamy Gleyed Matrix (F2) D Depleted Below Dark Surface (A11) llll Depleted Matrix (F3) I D Thick Dark Surface (A12) D Redox Dark Surface (F6) D Sandy Mucky Mineral (S 1) D Depleted Dark Surface (F7) 31ndicators of hydrophytic vegetation and wetland D Sandy Gleyed Matrix (S4) D Redox Depressions (F8) hydrology must be present, unless disturbed or oroblemalic. I Restrictive Layer (If present): Type: Depth (Inches): Hydric Soils Present? Yes llll No D Remarks: At line between A/B horizons, conlained charcoal-like organic material. <1 cm band of mottles between A/8 horizons. I I HYDROLOGY Wetland Hydrology Indicators: Primary Indicators (minimum of one required; check au that apply) Secondary Indicators (2 or more required) D Surface Water (A 1) D Water-Stained Leaves {89) D Water-Stained Leaves (89) llll High Water Table (A2) (except MLRA 1, 2, 4A. and 48) (MLRA 1, 2, 4A, and 48) I llll Saturation (A3) D Salt Crust (811) D Drainage Patterns (910) D Water Marks (81) D Aquatic Invertebrates (813) D Dry-Season Water Table (C2) D Sediment Deposits (B2) D Hydrogen Sulfide Odor (C 1) D Saturation Visible on Aerial Imagery (C9) I D Drift Deposits (83) D Oxidized Rhizospheres along Living Roots {C3) D Geomorphic Position (02) D Algal Mat or Crust (84) D Presence of Reduced Iron (C4) D Shallow Aquitard (D3) D Iron Deposits (85) D Recent Iron Reduction in Tilled Soils (C6) D FAC-Neutral Test (05) D Surface Soil Cracks (86) D Stunted or Stresses Plants (01) (LRR A) D Raised Ant Mounds (06) (LRR A) I D Inundation Visible on Aerial Imagery (B7) D Other (Explain in Remarks) D Frost-Heave Hummocks (07) D Sparsely Vegetated Concave Surface (88) Field Observations: I Surface Water Present? Yes D No llll Depth (inches): Water Table Present? Yes llll No D Depth (inches): 5.5" Saturation Present? Yes llll No D Depth (inches): surface Wetland Hydrology Present? Yes llll No D (includes capillary fringe) I Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: Remarks: US Anny Corps of Engineers Western Mountains, Valley, and Coast-Interim Version I I I I I I I I I I I I I I I I I I I I WETLAND DETERMINATION DATA FORM -Western Mountains, Valleys, and Coast Region Project Site: Applicant/Owner: lnvesllgator(s): May Creek Valley· DNRP King County DNRP Martin, Clark landform {hillslope, terrace, etc.): Valley lat: Subregion (LRR): Soil Map Unit Name: RdC,Bh 47.51495 City/County: King State: WA Sampling Date: Sampling Point: Section, Township, Range: S2, T23N, RSE 1-26-2010 Soil Pit #4 Local relief (concave, convex, none): nat Slope(%): 0.5 Long: -122.14239 Datum: NWI classification: PEM/PSS 181 No D (If no, explain in Remarks.) Are climatic/ hydrologic conditions on the site typical for this time of year? Yes Are Vegetation D. Soil D, Or Hydrology D, significantly disturbed? Are Vegetation D. Soil D. Or Hydrology 0, naturally problematic? Are "Normal Circumstances" present? Yes 181 No D (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS -Attach site map showing sampling point locations, transects, important features, etc. Hydrophytic Vegetation Present? Yes 181 No D Hydric Soil Present? Yes 181 No D Is the Sampling Area within a Wetland? Yes 181 No D Wetland Hydrology Present? Yes 181 No D Remarks: Soil Pit #4 Is located Just southeast of SE May Valley Rd/148th Avenue SE Intersection. Pit dug at the northern extent of the Spirea near 148th. VEGETATION U -·11 se sc ent1 f I cnameso pans Tree Stratum (Plot Size: 10m I Absolute Dominant Indicator Dominance Test Worksheet: % Cover Species? Status 1. Fraxinus lafifolia 60 y FACW Number of Dominant Species That Are 3 (A) 2. Fruit tree 5 N ? DBL, FACW, or FAC: 3. Total Number of Dominant Species Across 3 (B) 4. All Strata: 65 = Total Cover Percent of Dominant Species That Are 100% (AIB) Sapling/Shrug Stratum (Plot Size: 10 m) DBL, FACW, or FAG: 5. Spirea douglasil 15 N FACW Prevalence Index worksheet: 6. Rosa plsocarpa 20 y FAC Total% Cover of: Multiply by: 7. OBL species x1 = 8. FACW species x2 = 9. FAG species x3 = 35 = Total Cover FACU species x4 = Herb Stratum (Plot Size: Sm ) UPL species xS = 10. Phalarls arundinacea 100 y FACW Column Totals: (A) (8) 11. Prevalence Index= BIA= 12. Hydrophytic Vegetation Indicators: 13. Yes Dominance Test is >50% 14. Prevalence Index is .::_3.0 1 15. Morphological Adaptations1 (Provide supporting data in 16. Remarks or on a separate sheet) 17. Wetland Non-Vascular Plants1 18. Problematic Hydrophytic Vegetation1 (Explain) 19. 20. 1 Indicators of hydric soil and wetland hydrology must be present, 100 = T ala/ Cover unless disturbed or problematic. Woody Vine Stratum (Plot Size: ) 1. 2. 200 = Total Cover Hydrophytic Vegetation % Bare Ground in Herb Stratum 0 Present? Yes 181 No D Remarks: US Anny Corps of Engineers Western Mountains, Valley, and Coast -Interim Version Project Site: May Creek Valley -DNRP SOIL s p. I #4 I amp 1na 01n: Profile Description: (Describe to the depth needed to document the Indicator or confirm the absence of Indicators.) I Depth Matrix Redox Features (inches) Color (moist) % Color (Moist) % Type 1 loc2 Texture Remarks ---------0 -8.5" 10YR 2/1 100 Clay Oxidized roots 8.5-13.5" 2.5Y 2.5/1 50 10YR 5/6 50 Clay Bottom 1/3 of layer has mottles I 13.5-18 10YR 2/1 Clay Organic pieces, oxidized roots I 1Type: C= Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains. 2Location: I PL=Pore lining, M=Matrix Hydrlc Soll Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydrlc Solls3: D Histosol (A 1) D Sandy Redox (S5) D 2 cm Muck (A10) D Histic Epipedon (A2) D Stripped Matrix (S6) D Red Parent Material (TF2) I D Black Histic (A3) D Loamy Mucky Mineral (F1) (except MLRA 1) D Other (Explain in Remarks) D Hydrogen Sulfide (A4) D Loamy Gteyed Matrix (F2) D Depleted Below Dark Surface (A 11) 181 Depleted Matrix (F3) I D Thick Dark Surface (A 12) D Redox Dark Surface (F6) D Sandy Mucky Mineral (S1) D Depleted Dark Surface (F7) 31ndicators of hydrophytic vegetation and wetland D Sandy Gleyed Matrix (S4) D Redox Depressions (F8) hydrology must be present, unless disturbed or nroblematic. I Restrictive Layer (If present): Type: Depth (Inches): Hydrtc Soils Present? Yes D No D Remarks: The soil in the third layer is actually dark.er than the color noted, but there was not a good match in the Munsell. I I HYDROLOGY Wetland Hydrology Indicators: Primary Indicators (minimum of one required; check all that apply) Secondary Indicators (2 or more required) D Surface Water (A 1) 181 Water-Stained Leaves (89) D Water-Stained leaves (89) 181 High Water Table (A2) (except MLRA 1, 2, 4A, and 48) (MLRA 1, 2, 4A, and 48) I 181 Saturation (A3) D SaltCrust(811) D Drainage Patterns (810) 181 Water Marks (81) D Aquatic Invertebrates (813) D Dry-Season Water Table (C2) D Sediment Deposits (82) 181 Hydrogen Sulfide Odor (C1) D Saturation Visible on Aerial Imagery (C9) I D Drift Deposits (83) 181 Oxidized Rhizospheres along living Roots (C3) D Geomorphic Position (02) 181 Algal Mat or Crust (84) D Presence of Reduced Iron (C4) D Shallow Aquitard (D3) D Iron Deposits (85) D Recent Iron Reduction in Tilled Soils (C6) D FAC-Neutra1 Test (D5) D Suriace Soil Cracks (86) D Stunted or Stresses Plants (01) (LRR A) D Raised Ant Mounds (06) (LRR A) I D Inundation Visible on Aerial Imagery (87) D Other (Explain in Remarks) D Frost-Heave Hummocks (07) D Sparsely Vegetated Concave Suriace (88) Field Observations: I Surface Water Present? Yes D No 181 Depth (inches): Water Table Present? Yes 181 No D Depth (inches): 4S Saturation Present? Yes 181 No D Depth (inches): suriace Wetland Hydrology Present? Yes 181 No D (Includes capillary fringe) I Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: Remarks; I I US Army Corps of Engineers Western Mountains, Valley, and Coast -Interim Version I I I I I I I I I I' I I I I I I I I I I WETLAND DETERMINATION DATA FORM -Western Mountains, Valleys, and Coast Region Project Site: Applicant/Owner: lnvestigator(s): May Creek Valley -DNRP King County DNRP Miller, Clark landform {hillslope, terrace, etc.): Valley Lat: Subregion (LRR): Soil Map Unit Name: RdC,Bh 47.51495 Are climatic I hydrologic conditions on the site typical for this time of year? City/County: King State: WA Sampling Date: Sampling Point: Section, Township, Range: S2, T23N, RSE 1-28-2010 Soil Pit#5 Local relief (concave, convex, none): flat Slope(%): 0.5 Long: -122.14239 Datum: NWI classification: PEM/PSS Yes 181 No D (If no, explain in Remarks.) Are Vegetation Are Vegetation D, Soil D. Soil 0. Or Hydrology D. significantly disturbed? 0, Or Hydrology D, naturally problematic? Are "Normal Circumstances" present? Yes 181 No D {If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS -Attach site map showing sampling point locations, transects, important features, etc. Hydrophytic Vegetation Present? Yes D No 181 Hydric Soil Present? Yes D No 181 Is the Sampling Area within a Wetland? Yes D No 181 Wetland Hydrology Present? Yes D No 181 Remarks: Soll Pit #5 /s located slightly east and just upslope of Soil Pit #4 (SE of May Valley Rd/14811> Ave SE intersection). Selected spot within the change from reed canarygrass to blackberry. VEGETATION -Use scientific names of olants Tree Stratum (Plot Size: 10m) 1. Acer sp.* 2. Prunus sp. * 3. 4. Sapling/Shrub Stratum (Plot Size: 10m) 5. Oemlarla ceraslformls 6. Cory/us cornuta* 7. 8. 9. Herb Stratum (Plot Size: Sm) 10. Polystlchum munitum 11. Pteridlum aqullinum 12. Phalarls arundinacea 13. 14. 15. 16. 17. 18. 19. 20. Woody Vine Stratum (Plot Size: ) 1. Rubus procerus 2. % Bare Ground in Herb Stratum Absolute % Cover 25 15 40 20 33 53 20 20 20 60 45 198 Dominant Species? y y = Total Cover y y = Total Cover y y y = Total Cover y = Total Cover Indicator Status FACU FACU FACU FACU FACU FACU FACW FACU Dominance Test Worksheet: Number of Dominant Species That Are OBL, FACW, or FAC: 1 (A) Total Number of Dominant Species Across All Strata: 9 (B) Percent of Dominant Species That Are OBL, FACW, or FAC: 10 (A/B) Prevalence Index worksheet: Total % Cover of: Multi12ly by: OBL species 0 x1 = 0 FACW species 20 x2 = 40 FAC species 0 x3 = 0 FACU species 178 x4 = 712 UPL species 0 x5 = 0 Column Totals: 198 (A) 752 (B) Prevalence Index =BIA= 3.8 Hydrophytic Vegetation Indicators: No No Dominance Test is >50% Prevalence Index is ~3.01 No Morphological Adaptations1 {Provide supporting data In Remarks or on a separate sheet) Welland Non-Vascular Plants1 No No Problematic Hydrophytic Vegetation1 (Explain) 1/ndicators of hydric soll and wetland hydrology must be present, unless disturbed or problematic. Hydrophytic Vegetation Present? Yes D No 181 Remarks: *Vegetation was hard to Identify. The cherry tree appears to be ornamental -it is next to an ornamental cedar and the maple appears to be a sugar maple and not a native maple, but it Is hard to tell this time of year. US Army Corps of Engineers Western Mountains, Valley, and Coast-Interim Version Project Site: May Creek Valley -ONRP SOIL Samnlinn Point #5 Profile Description: (Describe to the depth needed to document the Indicator or confirm the absence of Indicators.) I Depth Matrix Redox Features I (inches) Color (moist) % Color (Moist) % Type 1 Loc2 Texture Remarks ---------0-18" 7.5YR 3/3 100 5YR 5/8 5 Clay Small mottles throughout [i I 1Type: C= Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains. 2Location: PL=Pore Lining, M=Matrix I Hydrlc Soil Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric Solls3: D Histosol (A1) D Sandy Redox (S5) D 2 cm Muck (A10) D Histic Epipedon (A2) D Stripped Matrix (S6) D Red Parent Material (TF2) I D Black Histic (A3) D Loamy Mucky Mineral (F1) (except MLRA 1) D Other (Explain in Remarks) D Hydrogen Sulfide (A4) D Loamy Gleyed Matrix (F2) D Depleted Below Dark Surface (A 11) D Depleted Matrix (F3) I D Thick Dark Surface (A 12) D Redox Dark Surface (F6) D Sandy Mucky Mineral (S1) D Depleted Dark Surface (F7) 31ndicators of hydrophytic vegetation and wetland D Sandy GI eyed Matrix ($4) D Redox Depressions (F8) hydrology must be present, unless disturbed or oroblematic. I Restrictive Layer (if present): Type: Depth (Inches): Hydrlc Soils Present? Yes D No 181 Remarks: I HYDROLOGY Wetland Hydrology Indicators: Primary Indicators (minimum of one required; check all that apply) Secondary Indicators (2 or more required) D Surface Water (A 1) D Water-Stained Leaves (89) D Water-Stained Leaves (89) D High Water Table (A2) (except MLRA 1, 2, 4A, and 4B) (MLRA 1, 2, 4A, and 48) I D Saturation (A3) D Salt Crust (811) D Drainage Patterns (810) D Water Marks (81) D Aquatic Invertebrates (813) D Dry-Season Water Table (C2) D Sediment Deposits (82) D Hydrogen Sulfide Odor (C1) D Saturation Visible on Aerial Imagery (C9) I D Drift Deposits (83) D Oxidized Rhizospheres along Living Roots (C3) D Geomorphic Position (D2) D Algal Mat or Crust (84) D Presence of Reduced Iron (C4) D Shallow Aquitard (03) D Iron Deposits (85) D Recent Iron Reduction in Tilled Soils (C6) D FAG-Neutral Test (05) I D Surface Soil Cracks (86) D Stunted or Stresses Plants (D1) (LRR A) D Raised Ant Mounds (06) (LRR A) D Inundation Visible on Aerial Imagery (87) D Other (Explain in Remarks) D Frost-Heave Hummocks (D7) D Sparsely Vegetated Concave Surface (BB) Field Observations: I Surface Water Present? Yes D No 181 Depth (inches): Water Table Present? Yes D No 181 Depth (inches): Saturation Present? Yes D No 181 Depth (inches): Wetland Hydrology Present? Yes D No 181 {includes capillary fringe) I Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), If available: Remarks: No indicators of hydrology are present here. US Army Corps of Engineers Westem Mountains, Valley, and Coast-Interim Version I I I I I I I I 1· I I I I I I I I I I WETLAND DETERMINATION DATA FORM -Western Mountains, Valleys, and Coast Region Project Site; ApplicanVOwner: lnvestigator(s): May Creek Valley -ONRP King County DNRP Miller, Clark Landform {hillslope, terrace, etc.): Valley Lat: Subregion (LRR): Soil Map Unit Name: RdC,Bh 47.51495 City/County: King State: WA Sampling Date: Sampling Point: Section, Township, Range: S2, T23N, RSE 2-24-2010 Soil Pit #6 Local relief (concave, convex. none): flat Slope(%): 0.5 Long: -122.14239 Datum: NWI classification: PEM/PSS No D (If no, explain in Remarks.) Are climatic/ hydrologic conditions on the site typical for this time of year? Yes Are Vegetation D, Soil D. Or Hydrology D, significantly disturbed? Are Vegetation D, Soil D, Or Hydrology D. naturally problematic? Are "Normal Circumstances" present? Yes 181 No D (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS -Attach site map showing sampling point locations, transects, Important features, etc. Hydrophytic Vegetation Present? Hydric Soil Present? Wetland Hydrology Present? Remarks: VEGETATION-Use scientific names of olants Tree Stratum (Plot Size: 10m) 1. Thuja p/lcata 2. Pseudotsuga menzlesll 3. Afnus rubra 4. Fraxinus latifolia 5. Prunus spp. Sapling/Shrub Stratum (Plot Size: 10m) 5. Oemlerla ceraslformls 6. Rubus spectabllis 7. Symphoricarpos a/bus 8. Amelanchler alnifolia 9. Herb Stratum (Plot Size: 5m) 10. Polystlchum munltum 11. moss species"" 12. 13. 14. 15. 16. 17. 18. 19. 20. Woody Vine Stratum (Plot Size: 1. Rubus procerus 2. % Bare Ground in Herb Stratum Yes Yes Yes Absolute % Cover 20 30 35 5 5 95 5 30 5 20 60 2 60 2 10 167 181 181 181 No D No D Is the Sampling Area within a Wetland? Yes 181 No D No D Dominant Species? y y y N N = Total Cover N y N y = Total Cover N y = Total Cover N = Total Cover Indicator Status FAC FACU' FAC FACW FACU FACU FAC FACU FACU FACU ? FACU Dominance Test Worksheet: Number of Dominant Species That Are OBL, FACW, or FAG: Total Number of Dominant Species Across All Strata: Percent of Dominant Species Thal Are OBL, FACW, or FAG: Prevalence Index worksheet: Total% Cover of: OBL species F ACW species FAG species FACU species UPL species 3 5 60 Multiply by: x1 = x2 = x3 = x4 = xS = (A) (B) (A/B) Column Totals: (A) Prevalence Index = 8/A = 3.4 (B) Hydrophytlc Vegetation Indicators: Yes Dominance Test is >50% Prevalence Index is ,::;3.0 1 Morphological Adaptations 1 (Provide supporting data in Remarks or on a separate sheet) Wetland Non-Vascular Plants1 Problematic Hydrophytic Vegetation1 (Explain) 1 Indicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic. Hydrophytlc Vegetation Present? Yes No D Remarks: *The indicator status of douglas fir Is still being studied. One of the fir trees in this plot was growing in standing water. **We did not include the moss in the dominance calculations. We also saw a trace of the native blackberry but did not Include that because the amount was <1%. This area passes based on the dominance test, so based on this finding hydrophytic vegetation is determined to be present. US Army Corps of Engineers Westem Mountains, Valley, and Coast-Interim Version Project Site: May Creek Valley -DNRP SOIL Samnlinn Point: #6 Profile Description: (Describe to the depth needed to document the Indicator or confirm the absence of Indicators.) I Depth Matrix Redox Features (inches) Color (moist) % Color (Moist) % Type 1 loc2 Texture Remarks ---------0-5" 10YR 2/1 100 Clay Almost to black to match the Munsell 5-18" 10YR 2/1 100 Too small, faint 20 C M Clay Texture is even more sticky than top layer i 1Type: C= Concentration, D=Deptetion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains. 2location: Pl=Pore lining, M=Matrix I Hydrlc Soll Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydrlc Solls3: D Histosol (A 1) D Sandy Redox (S5) D 2 cm Muck (A10) D Hislic Epipedon (A2) D Stripped Matrix (S6) D Red Parent Material (TF2) D Black Histic (A3) D loamy Mucky Mineral (F1) (except MLRA 1) D Other (Explain in Remarks) D Hydrogen Sulfide (A4) D loamy Gleyed Matrix (F2) D Depleted Below Dark Surface (A 11) 181 Depleted Matrix (F3) I D Thick Dark Surface (A 12) D Redox Dark Surface (F6) D Sandy Mucky Mineral (S1) D Depleted Dark Surface (F7) 3Jndicators of hydrophytic vegetation and wetland D Sandy GI eyed Matrix (S4) D Redox Depressions (F8) hydrology must be present, unless disturbed or nrob1ematic. I Restrictive Layer (If present): Type: Depth (Inches): Hydrlc Soils Present? Yes 181 No D Remarks: Both layers are clay, but the top layer is more crumbly and contains small gravels. HYDROLOGY Wetland Hydrology Indicators: Primary Indicators (minimum of one required; check all that apply) Secondary Indicators (2 or more required) D Surface Water (A1) D Water-Stained leaves (89) D Water-Stained leaves (89) 181 High Water Table (A2) (except MLRA 1, 2, 4A, and 48) (MLRA 1, 2, 4A, and 48) I 181 Saturation (A3) D Salt Crust (811) D Drainage Pattems (810) D Water Marks (81) D Aquatic Invertebrates (813) D Dry-Season Water Table (C2) D Sediment Deposits (82) D Hydrogen Sulfide Odor (C1) D Saturation Visible on Aerial Imagery (C9) I D Drift Deposits (83) D Oxidized Rhizospheres along living Roots (C3) D Geomorphic Position (D2) D Algal Mat or Crust (84) D Presence of Reduced Iron (C4) D Shallow Aquitam (D3) D Iron Deposits (85) D Recent Iron Reduction in Tilled Soils (C6) D FAC·Neutral Test (D5) D Surface Soil Cracks (86) D Stunted or Stresses Plants (01) (LRR A) D Raised Ant Mounds (D6) (LRR A) I D Inundation Visible on Aerial Imagery (87) D Other (Explain in Remarks) D Frost-Heave Hummocks (D7) D Sparsely Vegetated Concave Surface (BB) Field Observations: I Surface Water Present? Yes D No 181 Depth (inches): Water Table Present? Yes 181 No D Depth (inches): 9· Saturation Present? Yes 181 No D Depth (inches): surface Wetland Hydrology Present? Yes 181 No D (includes capillary fringe) I Describe Recomed Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: I Remarks: I US Army Corps of Engineers Western Mountains, Valley, and Coast -Interim Version I I I ,I I I I I I I I I I I I I I I I I WETLAND DETERMINATION DATA FORM -Western Mountains, Valleys, and Coast Region Project Site: Applicant/Owner: May Creek Valley -DNRP King County DNRP lnvestigator(s): Milter, Martin, Clark Landform (hillslope, terrace, etc.): Valley Subregion {LRR): Lat: Soil Map Unit Name: RdC,Bh 47.51495 City/County: King State: WA Sampling Date: Sampling Point: Section, Township, Range: S2, T23N, RSE 2-24-2010 Soil Pit #7 Local relief {concave, convex, none): flat Slope(%): 0.5 Long: -122.14239 Datum: NWI classification: PEM/PSS 181 No D {If no, explain in Remarks.) Are climatic/ hydrologic conditions on the site typical for this time of year? Yes AreVegetation D. Soil 0, OrHydrology D, significanllydisturbed? Are "Nonnal Circumstances" present? Yes 181 No D Are Vegetation D. Soil D, Or Hydrology D, naturally problematic? (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS -Attach site map showing sampling point locations, transects, Important features, etc. Hydrophytic Vegetation Present? Yes 181 No D Hydric Soil Present? Yes 181 No D Is the Sampllng Area within a Wetland? Yes 181 No D Wetland Hydrology Present? Yes 181 No D Remarks: This pit is located on the southwest side of May Creek near fence posts. The hole was pre-existing -it appears it may be leftover from when the fence was installed. VEGETATION -Use scientific names of olants Tree Stratum (Plot Size: 10m) 1. None 2. 3. 4. Sapling/Shrub Stratum (Plot Size: 10m) 5_ Spirea douglasli 6. 7. 8. 9. Herb Stratum (Plot Size: 5m ) 10. Phalarls arundinacea 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. Woody Vine Stratum (Plot Size: 10m ) 1. None 2. % Bare Ground in Herb Stratum 0 Absolute 0 25 25 75 75 100 Dominant Species? = Total Cover y = Total Cover y = Total Cover = Total Cover Indicator Status FACW FACW Dominance Test Worksheet: Number of Dominant Species That Are OBL, FACW, or FAC: Total Number of Dominant Species Across All Strata: Percent of Dominant Species That Are OBL, FACW, or FAC: Prevalence Index worksheet: Total% Cover of: OBL species FACW species FAC species FACU species UPL species 2 2 100 Multiply by: x1 = x2 = x3 = x4 = xS = (A) (8) (A/8) Column Totals: (A) (8) Prevalence Index= BIA= Hydrophytlc Vegetation Indicators: Yes Dominance Test is >50% Prevalence Index is ~3.01 Morphological Adaptations 1 (Provide supporting data in Remarks or on a separate sheet) Welland Non-Vascular Plants1 Problematic Hydrophytic Vegetation1 (Explain) 11ndicators of hydric soil and wetland hydrology must be present. unless disturbed or problematic. Hydrophytic Vegetation Present? Yes 181 No D Remarks: Some riparian plantlngs at edge of plot were recently installed, and are too small to provide any coverage. We excluded those plantings from this plot. US Army Corps of Engineers Western Mountains, Valley, and Coast -Interim Version Project Site: May Creek Valley -DNRP SOIL Samolina Point: #7 Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.) I Depth Matrix Redox Features (inches) Color (moist) % Color (Moist) % Type 1 Loc2 Texture Remarks ---------0-2" Duff layer Mostly reed canarygrass roots 2-18" 10 YR 3/2 80 5YR 5/8 20% C PL, M clay I I 'Type: C= Concentration, O=Depletlon, RM=Reduced Matrix, CS=Covered or Coated Sand Grains. 2Location: PL=Pore Lining, M=Malrix I Hydrlc Soil Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric Soils': D Histosot (A 1) D Sandy Redox (S5) D 2 cm Muck (A10) D Histic Epipedon (A2) D Stripped Matrix (S6) D Red Parent Material (TF2) I D Black Histic (A3) D Loamy Mucky Mineral (F1) (except MLRA 1) D Other (Explain ln Remarks) D Hydrogen Sulfide (A4) D Loamy Gleyed Matrix (F2) D Depleted Below Dark Surface (A 11) 181 Depleted Matrix (F3) I D Thick Dark Surface (A 12) D Redox Dark Surface (F6) D Sandy Mucky Mineral (S1) D Depleted Dark Surface (F7) 31ndicators of hydrophytic vegetation and wetland D Sandy GI eyed Matrix (S4) D Redox Depressions (F8) hydrology must be present, unless disturbed or nroblematic. I Restrictive Layer (If present): Type: Depth (Inches): Hydrlc Soils Present? Yes 181 No D Remarks: HYDROLOGY I Wetland Hydrology Indicators: Primary Indicators (minimum of one required; check all !hat apply) Secondary Indicators (2 or more required) D Surface Water (A 1) D Water-Stained Leaves (89) D Water-Stained Leaves (89) 181 High Water Table (A2) (except MLRA 1, 2, 4A, and 48) (MLRA 1, 2, 4A. and 48) I 181 Saturation (A3) D Salt Crust (811) D Drainage Patterns (B10) D Water Marks (81) D Aquatic Invertebrates (813) D Dry-Season Water Table (C2) D Sediment Deposits (B2) D Hydrogen Sulfide Odor (C1) D Saturation Visible on Aerial Imagery (C9) I D Drift Deposits (B3) D Oxidized Rhizospheres along living Roots (C3) D Geomorphic Position (D2) D Algal Mat or Crust (84) D Presence of Reduced Iron (C4) D Shallow Aquitard (03) D Iron Deposits (85) D Recent Iron Reduction in Tilled Soils (C6) D FAG-Neutral Test (05) D Surface Soil Cracks (B6) D Stunted or Stresses Plants (01) (LRR A) D Raised Ant Mounds (06) (LRR A) I D Inundation Visible on Aerial Imagery (87) D Other (Explain in Remarks) D Frost-Heave Hummocks (07) D Sparsely Vegetated Concave Surface (88) Field Observations: I Surface Water Present? Yes D No 181 Depth (inches): Water Table Present? Yes 181 No D Depth (inches): 12" Saturation Present? Yes 181 No D Depth (inches); (includes capillary fringe) surface Wetland Hydrology Present? Yes 181 No D Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), lf available: Remarks: US Army Corps of Engineers Western Mountains, Valley, and Coast -Interim Version ---------~--------- Photo 1: Typical May Valley flooding looking south from SE May Valley Road in central portion of study area (January 26, 2010) Photo 3: Scrub-shrub portion of the wetland near Soil Pit #1 in southwestern quadrant of the study area (January 21 , 2010) May Creek Channel Restoration Wetland Delineation 29 Photo 2: Looking south at an undeveloped portion of the wetland just east of 1481 h Avenue SE (January 21 , 2010) ~ Photo 4: Hydric soil at Soil Pit #4 in the northwestern quadrant of the study area (January 26, 2010) March 2010 Photo 5: Southern extent of the wetland near Soil Pit #3 in the southeastern quadrant of the study area (January 26, 2010) Photo 7: May Creek in the eastern portion of the study area where prolonged overbank flooding occurs (January 26, 2010) May Creek Channel Restoration W etland Delineation 30 Photo 6: May Creek in the central portion of study area where less overbank flooding occurs due to floodplain fill (January 21 , 2010) Photo 8: Flooded pasture areas within the wetland in the central portion of the study area (January 21 , 2010) March 2010 ------------------- ------------------- Photo 9: Hydric soil in Soil Pit #6 in the northwestern quadrant of the study area (February 24, 2010) Photo 11 : Wetland area on the south side of May Creek on the west side of 148th Avenue SE (March 1, 2010) May Creek Channel Rest oration Wetla nd Delineation 31 Photo 10: Fill area at the northwestern s i de of the study area outside the wetland boundary (February 24, 2010) Photo 12: Wetland boundary on the south side of May Creek on the west side of 148th Avenue SE where the blackberry begins to grow into the reed canarygrass (March 1, 2010) March 2010 I I I I I I I I I I I I I I I ,I I I I Q"fjl ~ King County Department of Transportation Road Services Division Engineering Services Section Environmental Unit King Street Center 201 South Jackson Street Seattle, WA 98104-3856 (206) 296-6520 Fax (206) 296-0567 TTY Relay: 711 www.metrokc.gov February 9, 2011 City of Renton Planning Division FEB I 2 iul.S TO: Doug Chin, Senior Engineer, Water and Land Resources Division, Department of Natural Resources and Parks FM: Julia Tumey, L.G., Environmental Engineer, Environmental Unit, Road Services Division, Department of Transportation and Jeff Burkey, Hydrologist, Water and Land Resources Division, Department of Natural Resources and Parks RE: May Creek Drainage Improvement Project: SE May Valley Road and 148th A venue SE -Sediment Assessment Introduction This memo,provides information on sediment conditions in May Creek from approximately 1481h Avenue SE upstream to I 64'h Avenue SE. This evaluation addresses geomorphologic controls, sediment sources, sediment behavior in the drainage and how the project actions are likely to influence future sedimentation in May Valley. The purpose of the following background evaluation is to provide information to assist King County Department of Natural Resources and Parks, Water and Land Resources Division in the design process for a drainage improvement project in May Valley. The proposed project location is shown in Figure I. Two questions have been raised regarding sediment associated with the May Valley drainage improvement project: Question 1: Will the project change sediment delivery downstream to May Creek? Question 2: After the proposed drainage improvement project and mitigation on May Creek in May Valley, will sediment refill the May Valley project area? l\1ay Creek Channel Restoration Project Project Vicinity e StudyArea o Mile Markers Stream Incorporated Areas Cougar Mounta i n Wildland Park N + l\larch 2010 tQ King County 0 95 190 760 .... 1111:====:Jlllll .... ====:::J Fee 380 570 1ht lr1onNtion inoWed Oft this rn.ap "· bNn oompled '¥ ~ Coun\t :IUl'ffrom a .. Mly of sow-CM aM Is si..il,.olto <t,---tone C0&.ri\' "'*• no,.,tM,...tic>rs o,-.,r.._, .,.,,.s o, ....,, ato '°°"'1C¥-'*"'lilt..s. ~ ... or riGHs ID the we ffst.lCft WOf'IN'loA. lhS docun:nt S Mt ~d *" t.a:t • • Ar,t-, p,oo.d. ~ C~\t dul not be aa• t:w •nt•'*•L sptOi,11 , ... d. alddefli.ll or CIONtq,.N:ntia ~-lndudh .. but nd:ltrittdto. lort,..,.,.-.. 01 wt pro• ruulng tomtht wtot misw• dflt l*rmltion oott.ine:d on 1\11 map. ,,,,.,,, .. eoftNs tNlporlr'*>mwition ontNI map S p,ohblwl _.,.i,,-...,.. ...... .,~coony. Figure 1 c ... 1tt1~mo1 i••~•roc I I I I I I I I I I I I I I I I I I I Doug Chin February 9, 2011 Page 3· There are a number of factors that were not available for the assessment: • The actual suspended sediment loads in May Creek in the project area, the suspended and bedloads from the tributaries and the relative contribution of sediment from different sources are not known. • The change in sediment loading over time due to changes in land use in the basin; logging, development, agriculture and channel dredging is not known. • All of the tributaries provide some amount of sediment to May Creek within the valley but the actual volume is not known. Long Marsh Creek delivers gravel to silt sized sediment to May Creek. A depositional area of gravel and sand is visible in May Creek. Estimates of the delivery rate for Long Marsh are made from surveyed elevation changes between a sediment-removal project in 2002 and 20 I 0. • Beaver dams above the project area trap sediment and release sediment periodically due to flooding or breaching. An assessment of the sediment behavior presented here is based on published basin information, aerial photo interpretation, survey data from 1965, 1979, 1993, 2002 and 2010, a soil-loss analysis by Jeff Burkey, sediment samples from the May Creek channel, and May Creek survey records and studies conducted for the project. This assessment provides a working hypothesis about sediment movement in the valley and the basis for future investigations. Background Geology and Stream History The wide and relatively flat May Valley (RM 3.9 to RM 7.0) was created by glacial ice melt runoff and is part of the "Kennydale Channel". The valley is underlain by recent alluvium over recessional outwash deposits and compacted glacial till. These deposits overlie Eocene Tukwila Formation. The formation is composed of volcanic tuff, fine- grained volcanic sandstone and volcanic tuff-breccia. The formation is reported to outcrop west of 1461h and forms a physical boundary between the downstream ravine and May Valley upstream. The geologic map is shown on Figure 2. The creek gradient within May Valley is 0.2 percent and the valley is predominately a depositional environment. Aerial photography and Lidar image of the valley show evidence of pre- dredging channel meanders. Historic survey mapping from 1872 shows May Creek as a meandering stream and Tributary 0291 a extending north to join May Creek just south of Indian Meadows rather than the current confluence approximately 1,440 feet west of 164 1h Avenue SE. The alluvial fans from Indian Meadows and Long Marsh Creeks appear on the 1872 map and the mapped location of May Creek is routed to the southwest around the higher elevations of the Long Marsh/Indian Meadows alluvial fans. The historic channel map for 0291 a is consistent with Lidar images showing meander scars in the valley. (Aerial photos and historic map information is located in Appendix A). May Creek was dredged to form a linear channel between 1910 and 1936 (Foster Wheeler, 1995). A description of May Creek by Bretz (1913) describes May Valley as a "swampy, wide bottomed old channel". A project plan dated 1935 (King County Map Vault) shows creek modifications extending from Lake Washington to 1641h Avenue SE. ·I I I I I I I I I I I I I I I I I I I May Creek, May Valley • Legend Qw-Wetland Deposits Organic Rich Sediment Qvr-Recessional Outwash Deposits Sand and Gravel Qvt-Vashon Till Compacted Mix of Silt Sand and Gravel Tpt-Tukwila Formation-Mix of Volcanic and Sedimentary Material 10 5 0 10 20 30 40 Miles ------ Figure 2 ~ King County I I I I I I I I I I I I I I I I I I I Doug Chin February 9, 2011 Page 5 Aerial photos from 1936 show the May Creek channel cut as approximately 25 to 30 feet wide as measured from the aerial photos. The photos clearly show the channel excavation boundaries. The channel is uniform with limited shrubs or trees. Periodic dredging is reported during the 1940s through 1960s (Foster Wheeler, 1995). Property owners may have removed sediment periodically. Sediment Sources to May Creek Agriculture and Pastures In the immediate area of the proposed project there are roughly 8.4 hectares of active animal pasture that abut the stream on both sides with a few animal access points to the stream water (assumed watering holes). Under existing conditions, these animal pasture areas are flooded at stream flows below mean annual flow rate (8.6cfs)-over-bank flooding begins approximately at 6 cfs at the low point in the bank. Thus, its likely sediments that may not have washed off during a rain event with overland flow will be washed off when the stream-system capacity is exceeded and floods overbank. After a flood event, there does not appear to be any visual deposition of sediments resulting from the stream itself and upstream conditions but erosion rills are present in the pastures. Thus, it is assumed that sediments suspended in the water column that flush into the pasture retreat back into the stream system. Given this condition with the added animal activity, sediments from soil disturbance would be additive to upstream sediment loads, thus increasing sediment loads downstream. The proposed project goal is to reduce frequency of pasture flooding, thus sediment loads, from a frequency of any appreciable storm to a near one-year storm frequency. To assess potential sediment loads from pastures in the project area, similar studies in the Green River watershed were evaluated (King County, 2007). The Green River studies have estimated sediment loads (via total suspended solids) ranging from 50 to 170 kg/ha/yr; residential= 158 kg/ha/yr, commercial= 172 kg/ha/yr, forest= 110 kg/ha/yr, and agriculture = 50 kg/ha/yr. Literature values (Burton and Pitt, 2002) are significantly different with 10, 420, 3, and 343 kg/ha/yr for residential, commercial, forest, and agriculture, respectively. Monitoring stations used for agriculture land use in the Green River watershed study were downstream of pasture lands in ditches that had significant amounts of choking vegetation in them just upstream of the sampling station. Given the relative position of the sampling location and the proximity of vegetation upstream, one may expect the Green River sediment loads to be lower than expected because of the vegetation trapping wash-offloads. Consequently, estimated loads from the May Valley pasture areas are then estimated in the range of 50 -340 kg/ha/yr (assumed 200 kg/ha/yr average). Simplistically if we estimate loads from the pasture lands to be 200 kg/ha/yr, and post-project loads are reduced in half, then for a ten-year period and 8.4 ha, there is a reduction of 8.4 metric tons of sediment contribution to May Creek. An estimated range would be a reduction of 2.1 to 8.4 metric tons of sediment contributed to May Creek. Doug Chin February 9, 2011 Page 6 Hydraulic model results estimate that the channel capacity to carry bedload and suspended sediment through the project area will be increased after the proposed project by increasing the channel efficiency. Velocities associated with lower flow rates are increased with the removal of vegetation choke points in the channel along with channel- bottom high points that otherwise create backwater conditions conducive to deposition, while depths are increased with a lower channel bottom in conjunction with more water kept in-channel rather than over bank because of improved flow-rate capacity. Reduced overbank flooding into reed canarygrass may allow the annual volume of fine sediment and muck moving downstream to increase on a yearly basis. Higher flow or flood events would continue to carry stored in-channel and off-channel fine sediment downstream in a larger pulse, rather then metering sediment at lower flows. The cumulative total volume of sediment over a longer time frame, ten years for example, would not be expected to change. May Creek bottom sediments were sampled by the King County Department of Transportation Materials Laboratory (King County, May 2010 and October 2010, Appendix B). In the area of 1461h Avenue SE the channel bottom is composed on sands and gravels, to well-graded gravel. Larger gravel, cobbles and occasional boulders are also present. In the relatively flat and low-gradient portions of May Valley in the area of 148 1 h Avenue SE the hard channel is composed of silty-sand and sandy-silt. At the confluence with Long Marsh Creek the hard-channel bottom is composed of well-graded gravel. A variable layer of semi-liquid, organic rich mud (herein referred to as muck) is present within the stream channel behind constrictions in the channel (Figure 3). The muck was sampled 25 feet upstream of a private bridge at RM 4.6. A modified Loss on Ignition analysis (LOI) was performed on the sample and the organic content was approximately 28 percent. This is a very high percent organic material compared to King County streams (Burkey, personal communication). The exact source of this high organic content is unknown; however, the tributary stream channels within the project area do not contain the same muck material and the most likely sources are pastures, agricultural fields and grass/tree litter within and above the project limits. Sources of Stream Sediment Most of the major tributaries to May Valley enter May Creek upstream of 1641h or downstream of 146'\ outside of the project area. From just below ! 48'h and 1641h four tributaries: an unnamed tributary (0291 a), Indian Meadows (0291 ), Long Marsh Creek (0289) and Greenes Creek (0288) enter May Creek. Small alluvial fans occurring at the base of Trib. 029 la and Indian Meadows identify where sediment is deposited at the valley floor. o A ditch carries Indian Meadows Creek to May Creek. The ditch carrying Indian Meadows has piles of sediment adjacent to the ditch. These appear to be hand dug sediment piles removed from Indian Meadows Creek (Bauman, personal I I I I I I I I i I I i I I I I I I I I I I I I I I I I I I I I I I Doug Chin February 9, 2011 Page 7 communication). Finer sand and silt reached May Creek and the confluence with May Creek is clogged with silt and reed canarygrass (GeoEngineers, 2008). o Tributary 0291 a is shown on the 1872 map and before development of the valley flowing northwest parallel to May Creek, joining May Creek near the confluence with Indian Meadows. The stream now joins May Creek downstream of 1641h and is hydraulically controlled by a culvert under SR-900. Sediment is primarily deposited upstream from the culvert (Foster Wheeler). The creek lacks a defined channel above the confluence with May Creek. o Greenes Creek enters May Creek west of 148 1h Street and currently does not contribute significant sediment to the project area because Greenes Creek discharges to a wetland and the confluence with May Creek is choked with reed canarygrass. Table I: Two year flow for May Creek Tributaries in the Project Area (Foster Wheeler, 1995). Drainage Unnamed Trib. Indian Long Marsh Greenes 0291a Meadows 2 year flow in 23.8* 17 42 26 cfs *USGS StreamStats Esttmate Within the project area, Long Marsh is one of the largest flow (Table I) and sediment inputs. The Long Marsh sediment deposits constrict flow and muck movement in May Creek. Long Marsh Creek joins May Creek south of May Valley Road near 150th Place NE. Aerial photography from 1936 shows the creek in a relatively straight channel. The current channel is on the order of two (2) feet wide and several inches in depth at winter low flow. The stream banks are approximately one foot in height, and the surrounding floodplain/fan surface is primarily planted in pasture grass with some recent native plantings. Evidence was found of gravel deposition throughout this reach. Discussions with earlier property tenants indicate that sediment deposition extended into the adjacent pastures following a January 2009 storm event. Long Marsh Creek deposits form an alluvial fan composed of cobble-to silt-sized particles and discharge silt, sand and gravel into May Creek. May Creek channel bottom elevations are higher near the confluence and this channel fill is a choke point for flow within the channel. During high-flow events, Long Marsh carries large gravel-sized sediment to May Creek. Before Long Marsh was straightened, the stream would have migrated across the alluvial fan as sediment was deposited in the stream channel. As noted in the previous section, the Long Marsh and Indian Meadows alluvial fans built out into May Valley and forced May Creek around the fan. Doug Chin February 9, 2011 Page 8 May Creek Channel Changes with Time Horizontal Boundaries Aerial photos from 1936 show the May Creek channel cut as approximately 25 to 30 feet wide as measured from the aerial photos. The photos clearly show the channel excavation boundaries. The channel is uniform with limited vegetation. Foster Wheeler measured the mean May Valley Creek channel width in 1995 as 20 to 25 feet, with wider sections up to 60 feet at RM 5.6 (Foster Wheeler, 1995). In March of2002 a stream survey was conducted between 1641h Avenue SE and 148 1h Avenue SE (O'Rollins, 2002) and measured the average channel width at ten to 14 feet. A stream survey was conducted in 20 IO (Thompson and Bauman), and the average wetted width of habitat units was approximately 12.1 feet and the widest wetted width was 23 feet (surveyed reach RM 4.35 to RM 4.87). While no change in average width occurred from 2002 to 20 I 0, there is a possible pattern of channel narrowing between the 1936 and 1995 and comparison between the 2002 and 20 IO stream surveys. This is reflected in the available measurements; especially in areas dominated by reed canarygrass. The channel is still a relatively straight excavated ditch but grass, shrubs and trees have encroached into the channel. Survey data from 2002 and 2010 surveys are also available. Cross sections of May Creek are shown in Figure 4 ( cross section locations are shown in Figure 5). Five cross sections were chosen to compare the stream channel at relatively fixed locations in the stream. Upstream of the road bridge at 1481h Avenue SE the channel is narrower and slightly shallower (Section B-B). Downstream of the bridge the channel is wider and more uniform in shape (Section A-A). The cross section at Long Marsh (Section D-D) shows the 2002 bank deposits (right bank) associated with excavating sediment from May Creek (private property owner activity) and the filled-in 2002 channel profile from Long Marsh Creek deposits. During the 2002 pilot excavation project in May Creek at the Long Marsh confluence, sediment was removed to approximately elevation 309. The left bank (looking upstream) has now filled in to 2002 elevations at the confluence but the rectangular channel shape is still present on the right bank. Upstream of Long Marsh Creek, the channel is approximately the same width but shallower. This may be due to where the survey staff was placed and the CAD program interpolating between points. Downstream of Long Marsh Creek the channel has narrowed. Survey locations varied slightly between center line, right bank or left bank and cross section elevations are approximate. I I Ii I I I I I i I I I ;: • s· " ~ • , , ._ " ,. • , n • 3 Elevatioo (fl) w w w w w !'\JO O _.. _.. f'\J ~141~~·"-41~ T'\ /" t ~ I Ir r-' ' I _4.265343 Do'Mlslream of Rock Weir. _ I ' -......._ r I 4.278770 Do'Mlstream of 146th Briel... I ----_ ~ '< _4.310823 KC Swv. ey ,.;,, "".~.... I : ~~ ~ j _4.323418c.. t ~·j ---+·----~·-.;...--- ~ 1_4.3~836 KC Su~ey y~r :!)10_ -..,. \Ir : : . ----------~ g 14.300391 KC Survey year w19 " \.._ 4.387575 KC Survey year 3:110 . Q ID ID ~ m N ~ 0 0 0 4.411003 j : ! 4.426539 KC Survey year 3:110. 4.445406, ,I , :: .. I ..... I I .4.455 Brid:Je #3 148.h_~ __ -· -. ~ 4.472884 KC Survey year 3:110 (similar to OTA .. 4.482002 KC Survey year 3:110 1 ::::: . -~ --~ --1 -· -- -4.551~8 _ --,- 4.575359 KC Survey year :rno ~ ~:::.i" _4.6~73. I >-1 __ 4.62'2613 -·-"r --. 4.640315 I --'. ,. / /; I ' I / // N 4.700732 KC Survey year 3:110 (similar to OTAK X.. ' / I " I (" J .J./_ g: 0 0 4.749514 KC Survey year 3:110 (similar to OTAK XS .. • .. I : . \ 4.788456 KC Survey year 3:110 (similar to otak xs_. I / .4.828$0 K.c Survey y~r .a:i1p (similar to ~tak x .. 4.861266 ,---T- 4.887389 ~ 1 4.912045 KC SurveJ year 2J10 (similar to otak xs .. g 4 937175 ' ' ' ! r I 0 . ' ' ' ' ' 4.949111 KC Survey year 2010 (similar to otak xs .. 4.968724-' ·1 ' --_t_:_ 4.988154 " I \\ ' I ' ' // , ~ ',-, , \ ' ' ?', ,, 5.038008 otak xs 7!>15 5.04 foctb-i?Je upstrea"'! of Ct'!lasurdo pror>3rty ~ I 5.097SJ3 otak xs 'ug5 oj . 0 0 5.1:l1~4,o~ak xs .. 8005 5.185707 otak xs 8315 -,- \ \, \ I \ \ \' ,\ ~-~ ~ a IQ 0 0 a ,c g- 0 z ~ ex, ex, ;: :Q • ~ l', ~ • • ~ ~ ;: -. " [1 0 . ,,, 3 0 z I - It> N 0, " 0 0 ~ " 0 I ,,, 0 z I " "' " 0, ;:, 0 0 ~1,,1 rl!/1,g -. 01 0 -. ff> CC CC I CC I gi a ~ I I !1 '(BQ!Ol 'AJUTIO:) fiUl)I UIOJ:J) O!Ol Ul ssau1014.1 1uaw1pas1ony.J puu uo1JBAOI3 wonos puuP.lJ:) llmM01JS O{!JOJd 1aaJ:) AUy.J £ am\!13 6 ailud OJ OZ '8 Jaqwaoaa llllj:) \lnoa I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Doug Chin February 9, 2011 Page 10 Channel Bottom Elevation Channel elevation surveys were conducted in 1965, 1979, 1993, 2002 and 2010 (Data is located in Appendix C). A profile of May Creek channel from just below 148'h Avenue SE to approximately 1,300 feet upstream of the confluence with Long Marsh Creek as shown in Figure 5. The figure compares the 2002 and 20 l O survey profiles and gives spot elevations at the 14s'h A venue road bridge and at the horse-crossing bridge on parcel 0223059091, 15019 SE May Valley Road from 1965, 1979, and 1993. Upstream of Long Marsh, between 2002 and 2010 the hard channel bottom is a foot lower in some areas and a foot to two feet higher in others. At the horse bridge the elevation has varied from 307 feet to 311 feet associated with sediment deposition from Long Marsh Creek. From station 1 l+OO to 8+00 at 148 1h Avenue, the channel profile has flattened and the channel bottom has shallowed approximately three feet. This area coincides with thick areas of reed canarygrass. Between 1965 and 2010, the 148 1h Avenue road bridge channel profile has stayed relatively consistent at 307 to 308 feet. It appears from the elevation differences that where the muck and vegetation builds up, the channel bottom has also been aggrading. Changes in the bottom elevation should be considered approximate, perhaps within a foot of elevation change. Survey elevations have not been taken at the exact same locations and stationing is different between projects. Stream profiles in 2002 and 20 IO (Figures 4 and 5) show thicker areas of muck build up behind higher elevations in the channel. Up to four feet of muck was measured above the Long Marsh Creek confluence in 2002 and three feet in 20 I 0. Stream and elevation survey data indicates that soft muck present in the channel varies in thickness by location and with time. The muck thickness is variable and transitory, building up in the channel until higher flows in May Creek are able to move the sediment downstream. Muck and fine sediment is moved downstream by May Creek within the valley as bedload and suspended sediment. However, the valley and May Creek above May Valley is not the main source of sediment to Lake Washington. The May Creek Current and Future Conditions report (1995) identified the major source of sediment to the May Creek delta in Lake Washington as the May Creek canyon and eroding channels of tributaries that enter the mainstem downstream of May Valley. ,_. 320 320 3101· 300[ -100 3201 310[--- '-2010 CHANNEL :2002 :CHANNEL -----~\ 1/C --------·-------------------[310 Jo b 5\, c\300 1 0 SECTION A-A STA. 7+00 DOWNSTREAM OF 148TH ST (T\ NTS ............ '20,0 I -2002 1320 CHANNE _.- ;CHANNEL f' -------•----------"'! I ;---'310 ":~1oo ~ko 6 510 , i\~00 SECTION 8-B STA. 8+00 UPSTREAM OF 148TH ST NTS ffi '-"' MAY CREEK CHANNEL RESTORATION FIG. @] CROSS SECTIONS 320 320 3101· 300[ -100 ~ko 2010 CHANNEL 2002 CHANNE.k,.,... ~~ b 5\, SECTION C-C STA. 15+00 DOWNSTREAM OF LONG MARSH CREEK NTS -1310 poo 1 0 {D ............ 320~ 1 200~320 -r2010 ~CHANNEL ---.cc_ • CHANN L : ~ 3101 't' I ........................ ····················310 ":~1oo Jo 6 5\, 1 i\~00 SECTION D-0 STA. 16+00 LONG MARSH___C_R_EEK NTS ffi ............ 320)~---~------.---------~ I 320 2002 2010 I CHANNEL CHANNEL ------- 3101· 310 300[ -100 Jo b ~o c\300 1 0 SECTION E-E STA. 17+00 UPSTREAM OF LONG MARSH CREEK r5'\ NTS ............ NOTE: ALL CROSS SECTIONS ARE CREATED LEFT TO RIGHT LOOKING UPSTREAM. I I MAY CREEK CHANNEL RESTORATION FIG.~ PROFILES I 'o~~~~~~~~~~---,--~---,-----,-----,--~---,-----,-----,--~---,--~---,--~,-----,--,--,--~~,--~---,----:----:----:----:----:----:----:----:----:----:----:---:-;---:---;;::;;;::-c:::c:::C:::C:::-:::--:::---:----:----:----:----:----:----:----:----:----:----:----:----:----:----:----:----:----:----:----:----:----:--~--:----:----:----:-----------------------------------.----------~~------------------------~390 385 ·380 375 ·370 365 ·360 355 -350 345 ·340 335 -330 325 ·320 315 -310 305 ilOO 295 290 285 280 275 270 I I I I I I I I I I 335 I 330 I ::: I 315 I 310 I 305 I 300 Ill 295 I n 290 I I I 'AflP.ROX. ELE.VATION 1it(MLiCK AT''i't.i'.>W~Nt· ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~--,335 330 325 320 ~ ........... %:~P~~~KEW~~:UNE • _r~~~NEL ;r~~'NEL ~· ?7. • 1::: · 7 zzzzz222222zz.z7/-/// .. --4-? / : : : . . -. . . 305 300 295 ----9+00 10+00 11 +00 290 tl+UU I OOJ Pit ~I I 40 0 ·~ I 10 •• 120 SCALE IN FEET DETAIL 1 SCALE: 1·=40' iu z __ __ __ __ ------------------00 1, Ill]. --D SCALE IN FEET 335 335 330 325 320 315 310~-~~~~ 305 300 295 16+00 : r.APPROX. ELEVATION: : .. r.2010 · • --OF MUCK AT FLOWUNE · .L ---C~NEL . /. -----.- 17+00 18+00 19+00 20+00 DETAIL 2 SCALE: 1 • = 40' 330 325 320 315 310 305 300 295 21+00 22+00 23+00 I 1:1 l!I ei .; 41 11 /.I ,J] ., 80 SCALE IN FEET I I I I I I I I I I I I I I I I I Doug Chin February 9, 2011 Page 13 Findings: Project Features and Estimated Results Pre-project May Creek Sediment Sources and Channel Behavior above the May Creek Ravine: Based on field reviews of the project area, stream report (King County, 20 I 0), a literature review of past reports on the May Creek basin, and a review of aerial photographs a qualitative estimate of sediment sources has been developed. Sediment entering the project area comes from: • Upstream May Creek (east of 164 1 \ Most of the major tributaries enter May Creek above the project and therefore will be a contributor to suspended sediment in the Creek. Six beaver dams are present or have been active in the past above the project area; two below 1641h and four upstream of the project. • Long Marsh Creek is a contributor to channel fill by sand, gravel and small cobbles. The larger materials are able to reach May Creek during high flows due to the straight channel, slope and past channel maintenance by property owners. • Indian Meadows Creek is a minor drainage that is partially ditched through a pasture that reaches May Creek and contributes sediment to May Creek. • Tributaries (029 IA, 0291) contribute minor but unknown amounts of fine sediment. • Stormwater runoff and pasture flooding contributes an estimated .2 to .8 metric tons of organic material and sediment to the stream. The May Creek channel is essentially a ditch, excavated in a historic wetland system prior to l 930. The gradient in May Valley is very low and the creek is only able to transport clay to sand sized sediment. • The May Creek channel stores organic muck/sediment from pastures behind relatively high spots in the channel bottom and releases it downstream to the ravine during higher flows. Muck then builds up again as flows recede and during rain events. Some of the muck contributes to aggrading the channel bottom as it is trapped and entrained by vegetation. The May Creek project proposes a number of features to reduce sedimentation to May Creek and channel filling. The 70% design plans include: • removal and control of reed canarygrass (Phalaris arundinacea); • native plant buffers along the banks; • reducing overbank flooding; • selected removal of vegetation from the channel downstream of 1481h Avenue SE; • excavated alcoves adjacent to the channel downstream of! 48'h A venue SE, • a sediment management design for Long Marsh Creek, the primary source of sediment and channel constriction in the project area. These features are expected to produce the following results: • Removal and control of reed canarygrass will slow channel narrowing and infilling due to growth during spring and summer during low flows. Doug Chin February 9, 2011 Page 14 0 Adding plant buffers on either side of May Creek will shade the banks where reed canarygrass is present and help control grass growth and encroachment. 0 Reducing over-bank flooding of pastures will reduce the amount of sediment and organic material being carried to the creek by an estimated .2 to 0.8 metric tons per year. 0 Improved channel hydraulic efficiency will improve and move fine sediment and organic material that reaches the creek downstream, reducing the amount of sediment trapped in reed canarygrass above l 48'h A venue SE. 0 The proposed alcove excavation and planting areas west of 148 1h Avenue SE will allow the creek to overflow into the alcoves during higher flows; this will slow the current velocities and minor amounts of sediment will drop out of suspension, but the amount of deposition is unknown. 0 The May Creek channel is likely to be both a depositional area and a source of suspended sediment during higher flows. Soft muck in the stream bottom above the confluence with Long Marsh Creek is a combination of organic material from pasture runoff with mineral sediment. The muck builds up in the channel after rain storms and floods and is moved downstream during higher flows. Reducing flooding within the project area will help reduce the build up of muck in the channel. 0 A mitigation project in Long Marsh Creek will intercept gravel and large sand-size sediment reaching May Creek. 0 Bank stabilization with jute netting and seeding will reduce erosion and sediment input to May Creek after excavation. Estimated Changes in Sediment Transport and Channel Dimensions after Drainage Improvement Project: The proposed project elements and existing conditions were evaluated for how sediment would enter and move within the project area. If no change in behavior was expected, the conditions were assumed to remain the same and are listed below as "constant". If the project element was expected to modify sediment behavior by qualitatively reducing the amount of sediment reaching May Creek, a reduction is noted in the bulleted list below. During construction, temporary increases in sediment are possible and this is noted. ~ Constant Upstream May Creek (east of 164'\ Most of the major tributaries enter May Creek above the project and therefore will continue to be a contributor to fine sediment in the Creek. Beaver dams will hold back sediment and periodically release it when breached. ~ Constant Tributaries (0291A, 0291 and Indian Meadows Creek) contribute unknown amounts of fine sediment. These are expected to be minor. 0 Reduction Small proposed mitigation alcoves downstream from l 48'h will allow sediment to deposit at higher flows. 0 Reduction Long Marsh Creek mitigation project will minimize course sediment reaching May Creek and channel infilling. 0 Reduction Reduced pasture flooding will reduce the organic material and sediment discharged to the stream, estimated at .2 to .8 metric tons. I I I I I !j II I I I I I I I I I I I I I I I I I I I I I I I I Doug Chin February 9, 2011 Page 15 " " " Reduction Reduce channel narrowing by controlling reed canarygrass along the banks by establishing a buffer of plants on either side of the channel and shading the banks. Temporary Increase Channel excavation will temporarily expose "raw" bank and channel sediments to the channel. Jute matting and bank planting will control erosion but minor erosion within the channel may occur as the channel stabilizes. Change in fine sediment movement Fine mineral and organic sediments that reach May Creek and are now stored in the stream channel or trapped by grass during low flows will move downstream during lower flows. Fine sediment and organic material currently stored in the channel and moved downstream during high-flow events, will move downstream at a constant rate rather than episodic rate. The overall estimate is a net reduction in fine sediment and organic material reaching May Creek within the project area. Long Marsh Creek mitigation, the mitigation alcoves, reduced flooding, and reed canarygrass control are project features that decrease sediment contributions to May Creek in the project area. Controlling willow and reed canarygrass will control channel narrowing. Responses to Questions on Project Performance Question 1: Will the project change sediment delivery downstream to May Creek? Response: The May Creek Current and Future Conditions report (Foster Wheeler, 1995) identified the major sources of sediment to May Creek as coming from the ravine and tributaries below May Valley. The hydraulic analysis (King County, 2010a) shows that changes in flow velocity below 143rd Avenue SE are negligible. Sediment movement is controlled by flow. Therefore, the same size sediments would be moved within the May Creek system. Muck sediments are currently stored behind topographic highs in the stream channel and are moved downstream in pulses during high flow events. In general fine sediment that does enter the creek as bedload or suspended sediment will move downstream due to improved channel efficiency rather than being stored in the creek channel above 148th, incorporated into the banks and moving though during large flow events. However, some fine sediment or muck that does enter the creek will continue to be stored behind topographic highs in the channel or in topographic lows above and below 148 1 h Avenue. We estimate the project-related reductions in sediment delivered to the creek primarily from reduced overbank flooding, will reduce the total fine sediment and organic muck in the stream. Question 2: After the proposed drainage improvement project and mitigation on May Creek in May Valley, will sediment refill the May Valley project area? Response: We estimate that there will be an overall reduction in sediment contributions to May Creek within the project area. The stream channel bottom elevation is relatively stable, except where Long Marsh Creek discharges to May Creek and where reed cannarygrass and muck aggrades the channel. Reducing sediment and organic matter input to the channel from Long Marsh Creek and the pastures and removing reed Doug Chin February 9, 2011 Page 16 canarygrass will slow narrowing of the channel. Active monitoring and buffer-planting management along the creek banks will take place for ten years to allow establishment of native vegetation buffers. The larger channel can be expected to last beyond ten years. This assessment is based on qualitative analysis with available information. Quantitative sediment estimates are not available. I I I I i I I I I I I I I I I I I I I I I I I I I I I I I I I I Doug Chin February 9, 2011 Page 17 References Anchor QEA, LLC. 2110. May Creek Erosion Stabilization Draft Report May Creek Sediment Transport Study Phase 3. Prepared for King County Department of Natural Resources. Booth, D.B., Haugerud, R.A., and Sacket, J. Geologic map of King County, Washington: scale I: I 00,000. Bretz, J. Harlen, 1913, Glaciation of Puget Sound Region, Bulletin 8, Washington Geological Survey, 244p. Burton, G. Allen, and Robert Pitt. 2002. Stormwater Effects Handbook: A Toolbox for Watershed Managers, Scientists, and Engineers. Lewis Publishers, Boca Raton, Florida. http://www.epa.gov/ednnrmrl/publications/books/handbook/toc.pdf Foster Wheeler, l 995. See King County, 1995 below. GeoEngineers. 2008. May Creek Drainage and Restoration Plan, King County Washington. For King County Water and land Resources Division and Mid- Sound Fisheries Enhancement Group. Hart Crowser, 2009, Final Site Investigation Report, Loon Lake, Washington, prepared for the Washington Department of Natural Resources, 117 p. Access online September 20 IO at: http://www.dnr.wa.gov/Publications/agr loon lake final invest report.pdf Horner, Richard R., Joseph J. Skupien, Eric H. Livingston, and H. Earl Shaver. 1994. Fundamentals of Urban Runoff Management: Technical and Institutional Issues. Prepared by the Terrene Institute, Washington, DC, in cooperation with the U.S. Environmental Protection Agency. King County. 1995. May Creek Current and Future Conditions Report. Prepared by Foster Wheeler for King County Department of Natural Resources and Parks. Prepared for Stormwater Services Section, Capital Services Unit. King County. April 200 I, May Creek Basin Action Plan. King County Department of Natural Resources, Water and Land Resources Division. King County 2007. Water Quality Statistical and Pollutant Loadings Analysis -Green- Duwamish Watershed Water Quality Assessment. Prepared by Herrera Doug Chin February 9, 2011 Page 18 Environmental Consultants, Inc. http://green.kingcounty.gov/WLR/Waterres/StreamsData/reports/green- duwamish-loading-report.aspx King County. 2010a. DRAFT Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project. Prepared by Jeff Burkey, King County Department ofNatural Resources and Parks. Prepared for Stormwater Services Section, Capital Services Unit. King County. 2010b. King County GIS Center LIDAR, Topography, Geology, and Stream Location Layers, viewed with ARCGIS http://www5.kingcounty.gov/gisdataportal/ King County. 2010c. Particle Size Evaluation of May Creek Water Channel Soils, Job Number IB1205, Task MTR. King County Department of Transportation, Materials Lab, Renton, WA. King County. 2010d. Sediment Muck Analysis of May Creek Water Channel Sample, email communication, King County Department of Transportation, Materials Lab, Renton, WA. King County. 20\0e. May Creek Drainage Improvement Project 70% Design Progress Plans dated 10-22-10. King County. 201 Of. Baseline Stream Conditions May Creek Drainage Improvements, CIP#9A 1205. NCRS 1993. Soil Survey Division Staff. Soil survey manual. Soil Conservation Service. US. Department of Agriculture Handbook 18. h tip:// soi ls. usda. gov/technical/manual/ Yount, J.C. and Glower, H.D., 1991 Bedrock Geologic Map of the Seattle 30' by 60' Quadrangle, Washington: U.S. Geological Survey, Open-File Report OF-91-147, scale I: 1000000. II I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Doug Chin February 9, 2011 Page 20 May Creek Drainage Project, May Valley Lidar Image 79,ID:SCXD 79.000\58,00C237,00016,000 Feet ' + M'.! King County I I I I I I I I I I I I I I I I I I I "' ~. . . . • 1'\ .. (r, • ·. i \' jl, May Creek Drainage Project, May Valley 1936 Aerial Photo • ,: t ' . ~· . ' ft,,""~ ' .. , ,.,,,, ,, * 79,CB!Q500J 79.000158,00C237,00016,000 Feet ' ~ King County ., I I I I I I I I I I I I I I I I I I I I ~ ~~ Road Services Division Materials Laboratory Department of Transportation RSD-TR-0100 155 Monroe Avenue Northeast, Building D Renton, WA 98056-4199 www.metrokc.gov/roads May 11, 2010 TO: VIA: FM: RE: Jeff Burkey, Hydrologist, King County Department of Natural Resources and Parks, Water and Land Resources Division Ala~ Materials Engineer, King County Department of Trans~ort tion, Road Services Division, Materials Laboratory Tim~t-/2 Hyden, Engineer IU, King County Department of Transportation, Road ices Division, Materials Laboratory Particle Size Eyaluatlon of May creek water Channel Soils Job Number 1e12os. Task MIB The King County Materials Laboratory (KCML) obtained soil samples and performed field evaluations to determine the distribution of soil and rock particle sizes in the water channel along a section of May Creek. Areas from which samples were obtained or evaluations performed are summarized as follows: Area 1: Colasurdo Property (Red Barn) Sample KC-10-429: The sample was obtained using chest waders and a shovel from the north side of the water channel approximately 75 feet downstream from the bridge. The water was approximately 4 feet deep, flowing relatively slowly and the surface of the water channel consisted of very soft soils. This sample represents materials from approximately o· to 3" below the bottom of the channel. At the sample location, the bottom of the channel appeared to be exposed and was not covered with grasses. Particle size distribution tests were performed, including portions of the sample finer than a No. 200 sieve using a hydrometer, and the USCS classification for this material is sandy silt (ML). Sample KC-10-430: The sample was obtained from the same location and using the same methods as KC-10-429, except at a depth of approximately 3" to 6" below the bottom of the channel. At approximately 3" there was a transition in the soil and it was visually classified as a mixture of the silt from KC-10-429 with gray, fine silty sand. Particle size distribution tests were performed, including portions of the sample finer than a No. 200 sieve using a hydrometer, and the uses classification for this material is silty sand (SM). Report of May Creek Sampling & Testing Particle Size Evaluation of May Creek Water Channel Soils Job Number 191205, Task MTR Area 2: McFarland Property (Yellow House and Out Buildings) Page 2 of 4 5/11/2010 Sample KC-10-426: The sample was obtained at the confluence of a small unnamed stream and May Creek, approximately 30 feet upstream from the bridge. The water depth was approximately 12 inches with moderate flow and the surface of the water channel consisted of clean sand and gravels. This sample represents materials from approximately O" to 6" below the bottom of the channel. No significant vegetation was noted at the sampling location. A gradation test using conventional screening methods was performed and the uses classification for this material is well graded gravel (GW). Sample KC-10-431: The sample was obtained using chest waders and a shovel from the south side of the water channel, approximately 100 foot upstream from the bridge. The water depth was approximately 4 feet deep, flowing relatively slowly and the surface of the water channel consisted of very soft soils. This sample represents materials from approximately O" to 6" below the bottom of the channel. At the sample location, the bottom of the channel did not appear to be covered with grasses. Particle size distribution tests were performed, including portions of the sample finer than a No. 200 sieve using a hydrometer, and the uses classification for this material is sandy silt (ML). Area 3: 1481h Avenue SE Sample KC-10-432: The sample was obtained using chest waders and a shovel from the north side of the water channel approximately 75 feet downstream from the bridge. The water was approximately 4 feet deep, flowing relatively slowly and the surface of the water channel consisted of very soft soils. This sample represents materials from approximately O" to 6" below the bottom of the channel. At the sample location, the bottom of the channel appeared to be exposed and was not covered with grasses. Particle size distribution tests were performed, including portions of the sample finer than a No. 200 sieve using a hydrometer, and the uses classification for this material is silty sand (SM). Area 4: 1461h Avenue SE Sample KC-10-427: The sample was obtained using hip waders and a shovel from the thalweg area of the creek channel, immediately adjacent to the upstream side of the bridge. The water was approximately 2 feet deep, flowing moderately fast and the surface of the water channel consisted of sands and gravels. Some of the fine sands were washed off the shovel while sampling due to the moderately fast water flows. It is roughly estimated that 75% percent of the bottom of the water channel surface area consists of sand and small gravel. Larger gravel and cobbles with a maximum particle size of about 4 inches make up the remaining approximate 25% of the channel bottom surface area. A gradation test using conventional screening methods was performed and the uses classification for this material is well graded gravel with sand (GW). The mid-stream bridge pier appears to have 12" to 18" rip rap placed as armoring on the upstream nose of the footing/pile cap. Report of May Creek Sampling & Testing I I I I I I I I I I I I • i I I I I I Particle Size Evaluation of May Creek Water Channel Soils Job Number 101205, Task MTR Page 3 of4 5/11/2010 Sample KC-10-428: The sample was obtained using hip waders and a shovel from the thalweg area of the creek channel, immediately adjacent to the downstream side of the bridge. The water was approximately 2 feet deep, flowing moderately fast and the surface of the water channel consisted of sands and gravels. Some of the fine sands were washed off the shovel while sampling due to the moderately fast water flows. It is roughly estimated that 60% percent of the bottom of the water channel surface area consists of sand and small gravel. A gradation test using conventional screening methods was performed on material finer than a 3" sieve and the USCS classification for this material is well graded gravel (GW). Larger gravel, cobbles and occasional boulders with a maximum particle size of about 12 inches make up the remaining approximate 40% of the channel bottom surface area. The sides of the channel directly adjacent to the abutment are armored with broken pieces of concrete. A few pieces of broken concrete were observed in the thalweg of the creek channel. Directly downstream from the concrete armoring the sides of the water channel are undercut. An estimate of the overall creek bottom material gradation was obtained in the vicinity of the thalweg. The evaluation of material gradation was determined by reaching into the water and randomly touching a location on the creek bed. Material encountered at the bottom of the creek bed larger than 1 inch was removed from the water and measured. Materials finer than 1 inch were visually assessed as being similar to materials from sample KC-10-428 that were also finer than 1 inch. The particular sizes of material found on the creek bed were recorded and are shown in Table 1. The dimensions shown in Table 1 are approximately equal to a square mesh sieve that the materials would pass. TABLE 1 Sieve Size *Count Sieve Size Count -1" Fines 5 5" 2 1 Y." 5 6" 1 2" 5 7" 1 3" 5 12" 1 4" 0 * Indicates number of times the referenced size of material was encountered. Area 5: 143rd Avenue SE Samples of fine materials for laboratory gradation testing were not obtained from the bottom of the creek channel. The water was approximately 18 inches deep and flowing fast. There was very little fine (sand size and smaller) material present on the creek bed surface and representative samples could not be obtained with a shovel or similar tool due to the fast flowing water. An estimate of the overall creek bottom material gradation was obtained in the vicinity of the thalweg. The estimate was performed directly adjacent to, and on the upstream and downstream sides of the bridge. The evaluation of material sizes was Report of May Creek Sampling & Testing Particle Size Evaluation of May Creek Water Channel Soils Job Number 161205, Task MTR Page 4 of 4 5/11/2010 determined as previously described for Area 4: 146u, Avenue SE, Sample KC-10- 428. Most all materials larger than about 3 inches had sharp edges and a few pieces of broken brick were encountered. Material size counts for the upstream and downstream sides of the bridge are shown below as Table 2 and Table 3, respectively. TABLE2 Sieve Size Count Sieve Size Count -1 1 /2" Fines 2 8" 2 2" 2 9" 0 3" 3 10" 0 4" 6 10" -12" 0 5" 5 12" -15" 2 6" 3 15" -18" 0 -7" 1 TABLE 3 Sieve Size Count Sieve Size Count -1 1 /2" Fines 1 8" 3 - 2" 0 9" 0 3" 1 10" 0 4" 2 10" --12" 1 5" 4 12" -15" 1 6" 8 15" -18" 2 7" 4 We appreciate the opportunity to have been of service and trust this report addresses your current needs. Please call me at 206-391-0552 or Alan Corwin at 206-296-7711, should you have questions or we can be of further assistance. Attachments: Figure 1 -Laboratory Test Results KC-10-426 through KC-10-428 Figure 2-Laboratory Test Results KC-10-429 through KC-10-431 Figure 3 -Laboratory Test Results KC-10--432 Report of May Creek Sampling & T estlng ---~~-------------- er LU z u:: 'a: LU u er LU Cl. C 0 6: 0 0 6 Particle Size Distribution Report U.S. SIEVE OPENING IN INCHES U.S. STANDARD SIEXE N~_MBER_~ HYDROMETER 1 Y, in. % in.. 3/8 in, #140 '::lf f :'11 l_' ~J_' ~[' -~~-_::_ ''lHJ' I_' -'i J' ffi' +--1tf w +t~-- BOl-r. -,----·······-· 1 ·,------r---/--· -,·----: --· --·-r--·-· I. --1-·-·11-1-,-··l-- 10111-·· ,-I ·-··-T ----,---· i--l ---,----]--lJ -·-·---,--!-.. --···-·---·--j · ·--------r 1+---·-1~-·· ____ } 6 in. 2 In: 1 In. Yz In. #4 #10 #2Q #30 #40 #60 #100 #200 ~,-+ 1--t11 --=H-'~-----~----1 1 1 1~-----:-~~1+-1-~---I-J ____ _ 301 - 1 --1--,-· 1t-t·· --·---· ---, '.' Tri _[ -r 1-1--·-i-I ----, i i"--i-r·, 1 1, I 201 ·---,---:-,·--1 J------. --:-.-1 ___ J·T'" --,---tt i 11.-····--JT1·1-1-·t"·f--1----,: 1 1 · -, ·--1 ,-r1 -~----i ,-J-r,-i -I -f ~-. : -r-+-n-h-, 1 · -Tr1·r·r· --r ·--- ·100 10 1 0.1 0.01 0.001 ~BAl!II SIZE -mm. %+3" ----c~arse %.§f'!! ... Fine---·-lc~~-..se I Mediu~Sandj_ Fine I Silt ·% Fines --·---- l 1.4 33.o I 43.6 I 5.2 I Clay_ 4.6 1.9 0.3 0.0 50.6 I 31.3 I 6.7 6.7 4.2 0.5 0.0 57.0 28.7 6.3 6.7 1.0 0.3 Source Sample # I Depth/Elev. Date Sam_e_led uses Material Descri_e_tion NM%1 LL I PL KC-10-426 4127DO QW Well,graded gravel NV I NP KC.-10-427 4/27/10 QW Well-graded gravel with sand NV I NP KC-10-428 4/27/10 GW Well-graded grayel NV I NP Client Kine Countv KING COUNTY O McFarland residence, upstreain from bridge D 146th Ave SE, upstream side of bridge Project May Creek Stream Bottom Evaluation 6 146th Ave SE, downstream side of bridge Project No. 1Bl205 _L..f;gure MATERIALS LABORATORY Tested By: .,v-"w'---------- -----------------~~ 11 O'. w z u: ... z w 0 O'. w a. Particle Size Distribution Report U,S .. S1EVE OPENING IN INCHES U.S. STANDARD SIEVE NUMBERS HYDROMETER 100 #140 : · . ' I I -·· .,oo 1#20011 • I ·, I -. #40 = I ' I ' ·1 . #20 #30 , ' I , ! _,_ ··-. 10 • • . 'I ! ' , • • ! "" , "c,,~~,,,,,_ .:'.• 11'1 I , I I J '1 L ' ' ·1 1 I -f L · .. J ... · 6ln. , 3 ;" 21 " I ',' I' ----iii 111_ i_i~-Ls+,I : I I tu_ ---i 1111 I - , r I IJ;J_. : 11 ... ,-_ 1 ._ ----·"1Tr·-[i __ i__l _ _l_ . __ J._. _ -_ , :_ i_,_: : 1 1 --~ 1,_1J,, -1.-1 1 _ 1---·1·,;_· 1 --·r·-~ -_ -. ---~~ . __ 901 ! .. ' L ______ -·il ·t 11 l' ---L I_ . ~ -, . I!! i i __ 1 __ 1------, . .... I . I ----,-. ' .!.. -I I . ' ! ' ---·-, , -~1-~ j ' Ju -... , 1.11 . , ' . ' . -' ' I .. \ -, " --,, . --1--J---1· '1 1, -------. ·---.• II. ; ' J..,!_1_~ .. ' --!--'" I . ---I I . -,-I ----I ' ,_i J ____ r ___ --,· I I J __ L ______ ·111 J. -j· ~-1~ 1 ~· 4 1 ' I 11 J 1 _1_ .. , 5 o/-, : I ... -. I I _L ' --. ·-1 I I : I ~ ---. I ~, ·1--, I ' .. • . ' ---'I c.. . ., ' . . . '"1-1 I r--I 1 .. 1 ... , ·-··-· --l[LJ ... , --r-,~~11 J ~- 14 -1 i i-- 401-·1· ·1 .,,. ---rr.n1-, ! I _L_ ---·11'-r -----, J --f,,-1-F,~~f1~~DN' _I I • , . -,--.-- 1 , I , ,_1.r.. 1 1 111 11 1 . I \ I I . ' .. i ' . . +.--'-. . . -, ! I I . -· '"' I : I . Jjl L LI ' J Ti I l 1 ! I I I I . 1:1 : · 1 : 11 I I I I I ', ' 3v 100 10 1 ·0.1 0.01 0.001 GRAIN 1SIZE -mm. %·Gravel %Sand % Fines . ----o/o +3" ! _______ j__ -Coarse Fine Coarse Medium Fine 0 0.0 0;0 2:0 2.4 10.5 33;6 0 o,o ·o,o I 0.5 4.2 i 21.5 45.9 " 0.0 7.7 I 0,8 0.5 I 6.6 19.5 I Source Sample# I Depth/Elev. I Date Safllpled I uses I 01 KC-10-4291 O" .. ,, -, I 4/27/10 I ML I 0 KC-10-430 I 3" -6" I 4/27/10 I SM I t>I IKC-10-431 I O" -6'' I 4/27/10 I ML I Client King Countv KING COUNTY Project May Creek Stream Bottom Evaluation Project No. 1Bl205 Figure 2 MATERIALS LABO RA TORY Tested By: vw ___________ _ I Silt Cla)'_ 38.1 ' 13.4 27.9 46.9 1 18.0 II I NM% LL I PL ' Material Description Sandv.silt I NV i NP Siltv sand I NV I NP Sandy silt I NV l ~1> H O Colossurdo 75 1 downstream from bridge, center of channel D Colosmdo 75' downstream from bridge, N third of channel tJ. McFarland 100' upstream from bridge, N third of channel ~t ----------------., !!II!!!! l!!!!!!!!I Particle Size Distribution Report U.S. SIEVE OPENING IN INCHES U.S. STANDARD SIEVE NUMBERS HYDROMETER 1 Y, in. o/.. in, 3/8 in. #140 6 in 3 in. 2 in. 1 in. 'h in. 1'tl #10 #20 #30 #40 #60 #100 #200 100 • ! 1 ! i 1 !! iJ I r l I J 1 ; r1: J 11~ 11--1 -~LI 11 ·, i • I ·1J jlj 1 , i 1 , · 11, · 11 , 9oJ-f--+ -·--1,] -1--1-----·--·---J-:· -1----r--r·---W, _L __ J ___ LLLJ ___ J __ \ j , 11 BOJ-1 I ... , . ·-·H·H--i-1--1--: • -, 'H·l-j TH··· ,------H~-'-r ITT --. -w 1-'--+·--r--~r TT-i-·•-1--·-. 701-+---J--t--H-H+j-··' ' : -----' ,_J ' I f·" '-· ~ -t+-'-I_J___ ~ so-I .---------[ -_-·--i---1----·---1-1-r·--\11 1 ,-, -r---,-r----:r---· ~ 40--I-,----,-·-·.·---·--------~' . ·1,--1··0 ··---·--1-T---·l~ -t~:J· 1-·---· ~-1--· ·---,·--- ~H-1 -, __ -'" ---• ---r, r~ l -j n·-' ~ --· 1rrtriJ--~~ 1, ,L--,-. -- 201-t--+---r---j-/·HH·· r J--·,------;-1-1-1--•--· ··--r--· ----r-H--1- J I I i I . 1::-r-·,---1 ·-T1rrrr-r1 --,--·-T1rr,---~,---r-i---,-·1-t-,-t1tt--r-1-rm··1-r1-i--r- 100 10 1 0.1 O.Q1 0.001 GRAIN SIZI= -rnrn, 0.0 % Gravel ---------1---------Coarse Fine 0.0 j 0.5 1---_·,-----%Sand ____ ------ 1 C_o~§~ _ _] Medium j Fine % Fines % +3" Silt Clay '0 1.1 I 14.5 i 50.5 33.4 I I I Source I Sam_ple # · j Depth/Elev. j Date Sampled l uses Material Oescri_e_tion 1 NM'%1 LL I Pl o] KC-10-432 I O" -6" I 4127/10 I SM Silty sand NV I NP I Client Kin.o; Countv KING COUNTY O 148th, 75' downstream from bridge, N third of channel Proj_ect May Creek Stream Bottom Evaluation PrQject No. 1B1205 I Figure 3 MATERIALS LABORATORY I I I I I I I I I I I I I I I I I I KingCounty Department of Transportation Road Services Division Engineering Services Section Environmental Unit King Street Center 201 South Jackson Street Seattle, WA 98104-3856 (206) 296-6520 Fax (206) 296-0567 TTY Relay: 711 www.metrokc.gov DATE: February 8, 2011 TO: File FROM: Julia Turney, LG 2493 King County Road Services Division Environm ental Unit RE: May Creek Organic Sediment Sample Results Sample Date: October 8, 20 I 0. MEMO Sample Location: The sample was obtained from the May Creek Channel approximately 25 feet upstream from the foot bridge crossing the May Creek Channel (Gambini and Tse~ay properties 15019 SE May Valley Road Parcel number 0223059091 and 10008 148 1 Ave SE Parcel 0223059075.) Sample Methodology: The sample was taken using a small three cup plastic container. The sample was scooped from the soft sediment layer on the bottom of the channel. Several passes were made in the sediment to obtain a full container and representative sample. Free water was decanted from the top of the container and the soft muck sample was poured into a wide mouth one quart plastic jar with a screw top. The jar was labeled and taken back to the KCRSD office at 20 I S Jackson Street, Seattle WA. The sample was stored in the sample refrigerator in a locked storage room from Oct. 9-11. The sample was transported to the King County Materials Laboratory (KCML) on October 12'h. Sample Analysis: The King County Materials Laboratory (KCML) performed testing to determine the percent of organic material. The sample was designated as "May Creek Sediment Muck-Gambini Prop., 25' Upstream from Bridge". The sample was initially placed in an oven and dried at a temperature of 140° Fahrenheit to a constant weight to determine moisture content. The dried material was weighed and placed in an oven at 440° Fahrenheit until reaching a constant weight to determine the organic material content based upon loss on ignition. Organic matter that had not ignited at a temperature of 440° Fahrenheit was observed in the sample. The remaining sample was weighed and placed in an oven at I 000° until reaching a constant weight to ignite additional organic material. May Creek Organic Sediment Sample Results Page 2 Sample Results: o Initial Moisture Content of Material Dried at 140° Fahrenheit: 498% (140° Fahrenheit Oven) o Total Loss on Ignition (Organic Content) of Material Initially Dried at 140° Fahrenheit: 15.3% (440° Fahrenheit Oven) o Total Loss on Ignition (Organic Content) of Material Initially Dried at 140° Fahrenheit: 28.2% (I 000° Fahrenheit Oven) o The moisture content percent is weight of water lost compared to the dry weight of the sediment sample. o The total percent organic material in the sample is 28.2%. o The organic material content percent is weight loss during the test compared to the dry weight of the sediment sample. o The 1000 degree test temperature may cause water loss in the clay mineral structure and this would contribute to a high reading for organics. The test was run until the sample weight was consistent. o 28.2% represents an approximate organic content but may be a slightly high result due to test conditions. References King County 2010a. Particle Size Evaluation of May Creek Water Channel Soils, Job Number IB1205, Task MTR. King County Department of Transportation, Materials Lab, Renton, WA. King County 2010b. Sediment Muck Analysis of May Creek Water Channel Sample, email communication, King County Department of Transportation, Materials Lab, Renton, WA. NCRS 1993. Soil Survey Division Staff. Soil Survey Manual. Soil Conservation Service. U.S. Department of Agriculture Handbook 18. http:// soils. usda. gov/technical/manual/ Oliver, H. et.al.200 l. Loss on Ignition as a Method For Estimating Organic and Carbonate Content in Sediments: Reproducibility and Comparability of Results, Journal of Paleolimnology 25: 101-110, 2001 I I I I I I I .1 I I I I ----l1!l!llfl l!!!l!!!I ----------~ ~ - May Creek Profiles Comparison 1993 Stream Profile Cross-sections Surveyed 4/1993 for HEC-2 Model for May Creek Basin Plan River Min Ch El Length Cum Chnl Station (ft) Chnl !ftJ Length (ft) 2756 298.3 10 10 3061 302.5 305 315 3571 ----+-303.3 510 825 3591 303.2 20 845 3596.5 146th Ave Bridge 3602 303.2 0.1 845 3622 304.4 20 865 4047 304.3 425 1290 4397 303.2 350 1640 4507 304.3 110 1750 4518.5 148th Ave Bridge 4530 304.3 0.1 1750 4580 304.4 50 1800 4630 305.3 50 1850 4825 305.3 195 2045 5310.5 Red Barn Pvt. Bridge 5316 306.9 0.1 2045 5366 306.4 50 2095 6041 305.8 695 2790 6646 306.8 605 3395 6652 Colasurdo East Pvt. Bridge 6658 307.2 0.1 6708 306.8 50 7123 306 455 7618 308.4 495 7628 308.1 10 7634 Private Bridge 7640 308.1 0.1 7650 308.4 10 StreamProfile_comp.xls tdp 11/20/2001 61y8.s- 3395 3445 3900 4395 4405 4406 4416 1965 Harstad Study Drainage Comprehensive Plan Referenced by 1981 May Creek Basin Plan Techlncal Appendix Seg Chnl Chnl Length # Elevation (ftl 930 300.4 20 929 304 895 928 304.1 930 927 304.1 1835 926 304.5 1860 924 305.9 4010 f-- -- 1979 Stream Profile FEMA Data for May Creek May Creek Basin Plan Technical Flood Profie/ for May Creek ·-~·-F Appendix, Figure C-1 -:_. __ Sta Chnl Chnl Length River Chnl Chnl Length ID Elevation (ft) Station Elevation (ft} 1 299.3 30 ~·--!"-------··- f-----·----- -------- ------- 2 304.9 842 AG 303.1 850 2A 304.2 1060 .3 303.5 1755 Al 304.3 1748 304 2055 AK 306.9 2540 305.4 3425 AM 307 3913 3A 306.8 3690 308 4455 AO 308 4969 1 of 2 May Creek Pron/es Comparison 1993 Stream Profile 1965 Harstad Study Cross-sections Surveyed 4/1993 for Drainage Comprehensive Plan HEC-2 Model for May Creek Basin Plan · Referenced by 1981 May Creek River Min Ch El Length Cum Chnl Station (ftl Chnl !ftl Lenath !ftJ 8835 307.1 1185 5601 9985 310.4 1150 6751 10935 310.1 950 7701 11435 313.3 500 8201 11735 313.5 300 8501 11835 313.5 100 8601 11849 164th Ave Bridge 11863 313.5 0.1 8601 11963 314.2 50 8651 12323 313.3 410 9061 13143 315 820 9881 13893 316.4 750 10631 · 14608 316.5 715 11346 15488 318.5 880 12226 16148 318.7 660 12886 16953 319.8 805 13691 17563 321.6 610 14301 17573 322 10 14311 17602 Renton-lssaq. Road Bridge 17631 322 0.1 14311 17641 321.5 10 14321 17741 321.5 100 14421 . 18026 326.1 285 14706 18216 327.7 190 14896 18316 327.8 100 14996 18323 SE Mav Vallev Road Bridge 18329 327.81 StreamProfile_comp.xls tdp 11/20/2001 0.1 14996 Basin Plan Techincal Annend/x Sta Chnl Chnl Length ID Elevation (ft) 921 313.5 9200 918 320.3 14955 915 327.8 15735 1979 Stream Profile FEMA Datil for May Creek May Creek Basin Plan Technical Flood Profiel for May Creek Annendix, Figure C-1 Sta Chnl Chnl Length River Chnl Chnl Length ID Elevation (ft) Station Elevation 1ft1 4A 306.1 5900 5 310.7 7030 6 314 8670 AS 314.5 8290 7 317 11340 8 317.1 12680 BA 319.9 13060 9 321.5 14380 BA 322 14045 10 328 15030 BC 328 14784 2 of 2 ~~=l(MI~~~--~~~~~~~~~- I I qq '., I CAD Values for drawing profile I Min Ch El Length Chnl (ft) (ft) 298.IP 10 I 302.5 305 303.3. 530 304.3 445 Elv Distance Cum Length Chnl Elv. Difference Div. By 10 Div. By 100 (ftl _.a.~ 0.10 10 -4.2 3.05 315 -0.8 Al.OS ·5.30 845 -1 .o0.1 4.45 1290 I 303.2 350 304.3 160 -305.3 245 1.1 e::tn) 3.50 1640 -1.1 ,0.11 1.60 1800;- -1 <0.1 2.45 2045 306.4 50 -1.1 <I0.11 0.50 2095 I 305.8 695 306.8 655 0.6 ,4=~()]> 6.95 2790 -1 40.1 6.55 3445 306 455 0.8 .· ;..-:·o:oa ~·-·-~··· 4.55 3900 I 308.4 515 307.1 1185 310.4 2100 -2.4 A>.24 5.15 4415 1.3 C::::2:~!:-11.85 5600 -3.3 ~0.33 21.00 7700 I 313.3 900 314.2 50 313.3 410 -2.9 .A().29 9.00 8600 -0.9 AJ.09 a.so 8650 0.9 _:,.-. 0.0.9 ..:, 4.10 9060 I 315 820 316.4 1465 318.5 1540 -1.7 ,0.17 8.20 9880 -1.4 ,0.14 14.65 11345 -2.1 /0.21 15.40 12885 319.8 805 -1.3 -{().13 8.05 13690 I 321.6 610 322 10 -1.8 .0.18 6.10 14300 -0.4 I0.04 0.10 14310 321.5 110 0.5 <::'O.Q.5, 1.10 14420 I 326.1 285 327.7 290 328.5 100 -4.6 ,.0.46 2.85 14705 -1.6 .. 0.16 2.90 14995 -0.8 Ml.OS 1.00 15095 I 329.2 305 -0.7 ..0.07 3.05 15400 I I I I I I I Min Ch El Length Chnl Cum Length Chnl (ft) (ft) (ft) 298.3 10 302.5 305 10 315 s-, 0 825 384.4 ~ 42 /Lhr' 88e.1 304.3 ~-n:, 1290.1 3Q3.2,,._ 350 1640.1 304,3 . 110 1750.1 CAD Values for drawing profile Elv Distance Elv. Difference Div. By 10 Div. By 100 0.10 -4.2 ~ 0.1 0.01 8.45 -1.2 -0.12 8.65 0.1 0.01 12.90 1.1 0.11 16.40 -1.1 -0.11 17.50 ,7q f ·~}it...Bridge •l\iW·~ ,1 _ ae4.a 9._1 .. ~ · ;, , I __., ~ 50 1800.2 -0.1 -0.01 18.00 385.3 ,Ae=\ 9.2 305.3 ~ Uf \ 2045.2 Bridge -38816.-!.9----89'.4-1 ----..;1;!Q41;,3- 306.4 50 2095.3 305.8 695 2790.3 306.8 605 3395.3 Bridge ' 387.2 306.8 306 308.4 398.1 Bridge aes.1 308.4 307.1 310.4 310.1 313.3 313.5 Bridge 314.2 313.3 315 319.8 321.6 9.1 50 455 d;} S-o\ 3385 4 3445.4 3900.4 4395.4 1496.4 4405 5 4415.5 5600.5 6750.5 7700.5 8200.5 8500.5 9060.6 9880.6 10630.6 322 10 14310.6 Bridge I_ @£i~-' " 'efef ~· ' ~ta; . - -0.9 -0.09 18.50 0 0 20.45 0.5 0.05 20.95 0.6 0.06 27.90 -1 -0.1 33.95 0.4 0.04 34.45 0.8 0.08 39.00 -2.4 -0.24 43.95 0.3 0.03 44.05 -0.3 -0.03 44.16 1.3 0.13 56.01 -3.3 -0.33 67.51 0.3 0.03 77.01 -3.2 -0.32 82.01 -0.2 -0.02 85.01 0 0 86.01 0 0 86.51 0.9 0.09 90.61 -1.7 -0.17 98.81 -1.4 -0.14 106.31 -0.1 -0.01 113.46 -2 -0.2 122.26 -0.2 -0.02 128.86 -1.1 -0.11 136.91 -1.8 -0.18 143.01 -0.4 -0.04 143.11 fPafllf I I I Ii I I I I I I I I I 11Cf ,,-Jk ~:.!2"62-------IM--~(.fllfil:,,:,-· "!II' IJil I I I I I I I I I I I I I I I ~ 10 14320.7 ) 321.5 100 14420.7 0.5 0 -0.7 -0.7 0.05 143.21 0 144.21 -0.46 147.06 -0.16 148.96 -0.01 149.96 -0.07 150.96 -0.07 154.01 1993 Stream Profile I I I HEC-RAS Plan River Sia Min Ch El (ft) Length Chnl (ft) Cum Length Chnl (ft) I i 2756 3061 298.3 302.5 10 305 10 315 X-sec 1 starts about here + about another 96 ft dis 3571 303.3 3591 303.2 510 2_0 825 845 K~". 3596.5 Bridge -u/1 .(:.;'-<.)., 845.1 -bTI' "i"OO ~ Al .-"-3602 303_.2 3622 304.4 4047 304.3 4397 303.2 4507 304.3 0.1 20 425 350 110 4518.5 Bridge 148th Ave Bridge 4530 ~ 0.1 4580 ~ 50 4630 305.3 50 4825 305.3 195 5310.5 Bridge 5316 306.9 5366 306.4 6041 305.8 6646 306.8 6652 Bridge 6658 307.2 6708 306.8 7123 306 7618 . 308.4 7628 308.1 7634 Bridge 0.1 50 695 605 0.1 50 k· 455 495 10 ~- 7640 308.1 0.1 7650 308.4 1'0 8835 307.1 1185 9985 310.4 1150 10935 310.1 950 11435 313.3 500 11735 313.5 300~ 11835 313.5 100J 11849 Bridge 164th Ave Bridge 865.1 / [I 1290.1 5 "" 1640.1 #~~ 1 !J I ~vcro 114 t)1~ 6,,.. 1750.2- 1.800.2 1850.2 2045.2 2045.3 2095.3 2790.3 3395.3 3395.4 3445.4 3900.4 4395.4 4405.4 4405.5 4415.5 5600.5 6750.5 7700.5 8200.5 8500.5 8600.5 ~ J),...._._ A4.--I # ~,-J 1l11~ t~te. I I I I I Ii ~~~'--.'li9' .. ,(I.,.<, ~--"669@),& -.J1.. --"711963 314. 50 ~ 8650.6· _/7 '. I {;,/ej ,J:11~ -·· 12323 313.3 410 9060.6 13143 315 820 9880.6 13893 316.4 750 10630.6 14608 316.5 715 11345.6 15488 318.5 880 12225.6 16148 318.7 660 12885.6 16953 319.8 805 13690.6 17563 321.6 610 14300.6 u 1 Ii I 11 I I I I I I I I I I I I I I I I I I I I 17573 322 10 14310.6 <:.e.ClCD 17602 Bridge Renton-lssaq. Road 01idge C\Jh,wt 17631 322 0.1 14310.7 17641 \Eii.) 1B 14328.7 y> ;:Jf q, f 17741 321.5 100 14420.7 18026 326.1 285 14705.7 18216 327.7 190 14895.7 . 18316 327.8 100 14995.7 S.E 1"\o.l\/.RJ.18322.5 Bridg~-section 10 is about here ...I. 18329 !mil 9.1 14995.B ';:;>' .ff ( 0 U ~l'i1~\~,icjJ 1AJ ........... ,,., •. "1:-,•, ••• ,;., ••. , ". ·-.-.·.'(:.-·.,¥ .. 0 t2: "' {;)" ~ I ..... ~ ~ ~ r<\ __, .... '"" \ 'D J ..... ..._ ''"'' k 0 ~ (l ~ \)" ~ ( cJ I' "' -~ ,' M.I:'\ r • 3o . I /,1 1-1-- 0 Jo ! i I I I I I I I i = i~ ~-----,,,11,~1-t---------------j,--------t----:1-------------- { t _\"P ------------· I:.; l.'~~~IMl.r> ---------------- --- ..... ! t ' , "'' v 4-... '·,) ' " '64:5 "" ~ •-____... ~ II' r:"J I" - , "'· 0 -7 (7o'J --...;::,' I I I I I I I I I I I I I I I I I I I 1)/) f t v I) 1979 May Creek Basin Plan's Stream Profile Sta. ID Elv Chnl Len9th Cum Length 1 299.8 0 0 cf 1.1 299.3 ~ 30 14 CP 304.9 842 2A 304.2 225 1067 3 304.7 ~ 1747 /'f/i~ dJ5 303.5·--=s 1787 .· ... ·,, 3A 306.8 2173 · --3960 ... 2°':.:3058_,! 4-308.2 4805 4A 306.1 . (~ 6173 5 310.7 -~ 7302 /bLf~@ 313.8 (17 9038 314 ~ 9078 7 317 11708 8 317.1 3 . 13056 BA 319.9 384 13440 9 320.8 ~ 14862 <;P.'loO(W 321.5 (.:) 14922 <;f Ws'I~ 328.2 15512 v.o! l«-,-11 328 @ 15870 \.l'l~D-~~:;r.v[·a h A550CI r.TE~ •·.w cRrn: nn.t.rnr,r:[ STt'f"I" ll!';\l.'\I;~' ~ 1977 i..·~ne jj I .. C "' 0 Rotton Se!lt'lent Inlet Outlet R,rnk Slooe ''ax . ... ..c -C C ... \.Jidth LenQth Elev. Elev. Vert./Horiz. FlO\·.' 0: ~ ., C u or (ft.) ( ms 1) (1'1Sl) Depth jRouq~ness I Re!Tlil rks .r:; -u .... .._ Pioe (ft.) .... C -"' 0: ... Di ii. Left !Rinht u E C ..c C: (1) (ft.) :, (1) "O tr. V, -I I I REEK M INSTEM (Downsjre~m_()rder) MAY 901 I CHl4 1290 1451.3!.51426.0±.5 1 /1 1 /1 3 jGra;sy roadside I Inflow at Segment 003 at upstream end. ditch 902 cu 1.5 80 426.o±.5 422.4!.5 --1.5 Concrete Two driveways. 903 CH 5 100 4.22 .4±. 5 416.4-t.5 2/1 2/1 3 Ro11dsi de ditch Bank erosion. 904 cu 1.5 30 416.4±.5 415.0±.5 --1.5 Concrete Driveway. 905 CH 3 400 415.o±.s 395.2*.5 l /1 1 /1 2 Roadisde ditch Rank erosion. 906 cu 1.5 30 395.2±.5 394.8±.5 --1.5 Concrete Driveway. 907 CH 2 110 394.8±.5 385.9±.7 1 /1 1/1 3 Roadside ditch Bank erosion, small inflow from Sub- catchment 3. 908 cu 1. 5 30 385.9±.7 384.5±.5 --1.5 Concrete Driveway. ~, 1909 CH 3 1,800 384.5±.s 357.o±.s 1/2 1/2 2 Natural channel flank erosion. 910 CH 5 40 357 .o±.5 356.0±.5 1/4 1/4 1 Brushy After inflow of Segment 044. 911 cu 3.0 30 356.0!.5 355.9±.5 --3.0 Corrugated steel Driveway to camparound in Subcatch- ment 5. 912 CH 4 1,850 355.9±.5 339.8±.4 3/5 3/5 3 Soil bnk, mud bot/Begin Harstad profile (-1965). 913 BR 3.0 20 339.8±.4 339.7±.4 --3.0 !Private drive; SE 109th Street. 914 CH 5 2,840 339.7±.4 327.9±.4 1 /1 1 /1 3 Bottom sand, ;> .. ~) -';:._-:;:;· .. ':.., .~· ~· ~~.: --gravel, mud Under Q_!;•,.,_~~j1Jt!$i$1 MP -".t,c • .; , ert. Vert. 5 326.6±.5 2/1 1. 5/1 3 ,,.,..,,;(r;,fl,-, 916 CH 5 917 CH 6 321.0±1 l /1 l /1 1.5 Below inflow of Seament 116. 11U --6 .1 Corruqated steel ~~12:8 x 8 foot culvert . ei r on upstream end t and 2.4 foot on downstream end. 919 CH 7.5 1/1 3 Mud bottom, grassy banks 920 CH 9.5 6±.3 1 • 5/1 1 /1 3.0 Below inflow of Segment 195. "\ Vert. Vert. 4.5 f'tffl.?\11::w#-,@Mfhiiui inflow of \i C egment 259. 922 CH €.5 2,090 313.5±.3 3rJ9.8±.4 1.5/1 1/1 4 Heavy brush in channel 9231 CH,8.5 13, 100 1309.8±.4 ~=~·lil/1 J;/1 ~3.5JGravel bottom ~ow inflow of Segment 319. 924 CH 6.5 1,320 30~~ 1 .4 305.9-tA .5/1 _ .5/1 3.5 . 11ud b?"~to~ ow inflow of Segment 333. -liiiilil -liii!!I --.-i -·- Y)~[)."i,•Ur.V!:·:T " A~-~r,c1 !'T(~ ....... ~· r:Rr.[K nrir..p;~r:r ~T~!~\ ,.ir,•::_1/':~\' ~ l q77 Paoe 14 .. C C, 0 Rotton Sement Inlet nutl et Rank <;looe ·~ax. +' .<:. -C C ... !•Ii dth Lenqth Elev. Elev. Vert./Horiz. Flow a: ~ "' C u or (ft.) (ms 1) (1'1Sl) Depth Rouo'1ness Remarl:s .s= -u .., ... Pipe (ft.) .., C -"' "' .., Di a. Left Rinht u E C .<:. C "' (ft.) ::, "' .,, VI VI - 925 CH 11.0 830 305.9±.4 30'4.5±.5 1.5/1 l/1 3.5 Mud bottom Below inflow of Sewnent 345. ·~·~:<.1 1,;--~· "i. ._'br.Si~:r>-~~£ y;.~~~'::-,.-:--J >·~·-y ,,--·'.',i ,'..,l--~-·-~/ ,_, Vert. Vert. 5.6 Mud bottom S;;r·~~ .... :;n~~£f@A/4#b-lta inflow of Seqment 369. (1%"<) · 927 CH 9.0 905 303.5±.4 304 .1-c.4 1 /1 1 /1 4.0 Thick mud bottom 928 BR 17 15 304.1±.4 304.0:!:.4 Vert. Vert .. 8 Five 1.5 foot Sma 11 bridge. 895...1- supports CH 14 304.0t.5 .5/1 . 5/1 2.5 Gravel bottom RR fi.8 arc 20 300.7!.4 -6.8 Concrete Small arch bridqe. CH 16 3,370 300.4!.4 .5/1 • 5/1 4.5 Gravel bottom End Harstad profile; 136th Ave. bridoe·does not affect flow. 932 CH 17 3,030 243!1 186±2 1 /1 1/1 4 Below Senment 472. G) I ~ 933 CH 15.5 3,220 186i:2 147.1±.5 1/1 1 /1 3.5 Below Seoment 535. 934 CH 16 1,390 147 .1±.5 l2l .3i:.5 1/1 1/l 4.5 Below Seqment 994. (Honeydel'I Creek). 935 CH 17 1,050 121.J±.s 107 .2t.5 l/1 1/l 3 Below Seqment 763. 936 CH 14 200 107.2±.5 100.2±.5 1/1 1/1 3.5 Below Seqment 787. 937 BR 7 .25 30 100.2-c .5 100.1±.5 --7.25 Bridge over NE 31st. 938 CH 15 280 100.1±.5 100.0±.5 1/1 1/l 3 Riorapped banks. 939 CH 15 490 100.0:!:.5 89. 3:!:. 5 1/1 1/l 3 Below Segment 784. 940 ,BR . 31 30 89. 3±. 5 90 .4:!:. 5 Vert. Vert. 6 Bridge over NE 31st; elevations ,,y l double checked. 941 CH 20 1,050 90.4t.5 · 77.4:!:.S 1/1 1/2 2.5 Gravel bottom 942 CH 20 3,980 11 .4t.5 34 .0±1 l/l 1/1 3 Below inflow of Segment 816. 943 BR 18 250 34.0tl 32.0±l 1/l l /l 50 1-405 freeway bridge as built in 1956 944 CH 20 930 32.0il 21 • 2± .1 1 /1 1/1 3 Gravel bottom 945 BR 40 30 21 • 2±. l 21.2±.1 l /1 1/1 12 Lake Hashin11ton Blvd. 946 WEI 36 3 21.5:!:.5 21.Si:.S Vert. Vert. 6 Concrete USGS GaginQ Station; V-shaped weir ~ 947 CH 40 so 20. 5±1 20. 6:!:. l 1/2 1/2 5 JI.S }f, 948 BR 40.5 15 20.6±.l 20.5±.l Vert. Vert. 12 Railroad bridge. 949 CH 25 530 .,, 20.5:!:.1 16.2±.2 2/1 2/1 5 950 BP. 32 25 16.2:!:.2 15.5±.2 Vert. Vert. 6 Concrete 951 CH 30 480 15.5±.2 12.9±.2 2/1 2/1 4 <,ravel Man~made chRnnel; enter Lake Hash. 43,800 Total ~4 JA JORDAN/ AVENT a, ASSOCIATES ' ''.},Q>i9\. May Creek Study Page 4 Segment Parameters After the subcatchment was divided into segments, each was described-by seven parameters as required by the SWMM rodel: 1) Channel bottom width OR pipe diameter 2) Segment length 3) Inlet elevation· 4) Outlet elevation 5) Bank slopes 6) Roughness 7) Maximum flow depth Existing information was reviewed to minimize field work. Major sources included: 1) 2) Topographic maps with 5, 10, and 20 foot contour intervals. These maps were crucial to check surveyed elevations, to supply spot elevations at many points, and to estimate some reriote inlet and outlet elevations. 3) USGS topographic map of 25 foot contour interval. In spite of the large scale, these maps provided the most accurate positions of stream channels. The upstream elevations of most natural channels in the uplan1s were taken from these maps. 4) Engineerinq plat maps for urbanized areas. These were used to locate storm sewers. As requested, all storm sewers greater than twelve inches are shown on the base map overlay, As can be clearly seen, most residential areas do not have storm sewers. 5) Road crossing plans for I-405, State Highway 900, 148th Avenue and 164th Avenue. In addition to describing channel segments, they provided references and checks for our survey. Values from the RIBCO study were mt used. A brief discussion about the accuracy, sources, measuring techniques and other pertinent information for each parameter may help in using the data most effectively. G-4 ~-+~,$,,: --~·-·,,· 11 ' ,\ t ~ ~ '. l \ ..... . ii.'/ , Ll J"\,_ ~ .'.' t ' fu Channel Bottom Width: May Creek Study Page 5 For Segments 912 -931, bottom width was measured by averaqin_g four to eight Harstad cross sections within each segment. In a majority of cases, bottom width was measured in the field. Please note that for tributaries flowing from the hills, channel dimensions were measured only on the down- stream end. If additional descriptions are needed, these segments can be· further investigated. Normal channel irregularities limited accuracy to within one foot. For Segments 919 -927, the completeness of the Harstad study enabled us to stretch this to within\ foot. Pipe Diameter: Culvert diameters were nearly all measured in the field to within ~.1 foot. Bridges were measured as accurately as possible, from !,05 to !.5 foot. In the table in Appendix 2, care should be taken to notice that crossinqs may have rectangular, oval or circular cross sections. Segment Length: Smaller values (less than 100 feet) were usually determined in the field by pacing. These are !2 feet. Longer distances were measured and carefully compared on the.base map and on at least one other map. Values from the most accurate map were chosen. Therefore, base map distances may not be the same as distances on the table. The table values should be regarded as the most accurate. Table values are at least ~20 feet. Inlet and Outlet Elevations: Determination of e 1 evation represented the majority of tir1e expended. Because of the absence or destruction of almost all benchmarks in the basin, most surveys were run from points of known elevations. These included spot elevations on road and topographic maps, engineering plat maps and bridge plans. The precision of these starting elevations has been taken into account in G-5 JA. JORCAN / AVENT 8o ASSOCIATES May Creek Study Page 6 assessing accuracy. Elevationssurv~e·d from benchmarks and these spot elevations are usually listed as !.5 foot. The elevations of some remote segments were taken ·from maps of 5 foot contour interval. They are evaluated as !2 feet. Elevations from the USGS map of 25 foot contour interval are assessed as I !5 feet. Elevations taken from the Harstad profile are given as !.4 foot. Llank Slopes: In Segments 912--931, bank slopes were measured on the Harstad cross sections. For most segments, bank slopes were estimated in the field. Natural channels are usually not trapezoidal as required by the SWMM model; and, therefore, precision in these values should not be expected. t1aximum Flow Depth: Aqain the natural changes and irre9ularities of stream channels prevented great accuracy in measuring the bank full depths. Values should be considered to be within one foot. Measurements for culverts represent the actual depth available for flow as of January, 1977. If the culvert has been filled, this wi 11 be evident because the maximum fl ow depth wi 11 be 1 ess than the pipe diameter. The accuracy of maximum flow depth in pipes is ±.1 foot. Maximum flow depth may :hange during flood conditions due to scouring or.filling. Roughness: Roughness was described briefly to aid in selection of a Manning's n. Culverts were noted as · either concrete or aorrugated steel, and the genera 1 conditions of channels were stated. For the mainstream of May Creek, roughness due to mid channel vegetation can be most adequately described by examining the available air photos. G-6 I I I I I I I I I I I I I I I I I I I -=30.___.....,~.9. 330 360 370 730 so 810 -5 e__ 'i.o O ~~--2.!.\4.----J,l!Y>!il.ll--~-=--··------ 2200 3010 3530 6540 25 6565 2090 8655 3100 11755 13075 13905 1393 14835 -;jf.~-~~:~~:~~H----~~;;t_ .•.... htli ,f'l ~ 104 , I !: {.f: 15765' 20 I q '1 r «~S'U-1) 4TV0'{ = :~;;;;:~;;:f ,'.i,"<;,:'fi:;':"1:;{' '-:i;i"-',,.,,,.,,,.,'. !<~., ,.; •..• ,, •._,,; •.. ,•,,, __ ,., ,-. __ _ TABLE 1 -SUMMARY OF DISCHARGES (Cont'd) "' ID r-7 = = Flooding source and Location North Fork Issaquah Creek At mouth At mouth (including overtopping from Issaquah Creek) East Fork Issaquah Creek At mouth West Fork Issaquah Creek Above Issaquah Creek confluence 2,900 feet upstream of 229th Drive S.E. Above tributary confluence near 208th Avenue S.E. Holder Creek Above confluence with Carey Creek Tibbetts Creek At mouth May Creek At USGS gage 12-119600 At Coal Creek Parkway -: __ ;,!; _ 14 !;th Avenue _:,. E. At 148th Avenue S.E. At 164th Avenue S.E.,, _________________ _ At s.E. Renton-Issaquah Road At S.E. May Valley Road At S.E. 109th Place May Creek Tributary Above confluence with May Creek Vasa Creek At mouth At cross section R t§) la'il iiiiJ -fiiil - Drainage Area rsa. miles> - 4.8 4.8 9.5 4.9 4.7 1.5 7.5 3.9 12.7 8.9 7. 7_ 6.9 4.8· 2 :ii : 1.2 0.9 1.5 1.37 0.53 -a;) 10-xear iiiiii:J 176 176 440 290 270 100 420 220 480 350 310 280 __ ?_00 130 59 46 72 55 24 - Peak Discharges (cfs) so-xear 100-xear soo-xear - 269 489 725 460 .440 160 660 355 315 835 850 550 530 200 800 425 445 1,995 1,100 790 770 280 1,150" 600 800 870 1,020 580 640 750 520 56Q 660 470 ----510 600 340 370 440 -220 -------240 ---280 100 110 130 78 87 100 120 81 38 iiiiiil iiiiiJ 140 93 44 iliiiJ 160 123 60 --- I I I I I I I I I I I I I I I I I I I 1 •• 1 ~~':fa~~ 0&W1er ~ ~ Management ~ Everyone lives downstream Engineering & Environmental Services I b411f: _ __cyJ...!.Al..JY _ _>,,c"---(2---"'[R=··-------Project----1 J!L13 vc 1q7'( "7f2£lM fl2,op lfS Comp tM Chk ___ Rev __ _ Date 11 / 1 -, / d. Date Date ( 6f<1Jd Page of Pages \•,y/(...0 I --,, ' ~,ies) l-------+----------+------1------·----·-·-··-···-···-·· ·-·- / ""'~ ( ~ ""7{( -0 L/__:.?f_2.c-)-/""""--/_ ~~ _S -/· __ J / L{-i DLf-)/ SWM-EnaWorkSheet 4/22/93 ,.\ T A a L E FLOODING 50.URCE CRO!iS S[CTION Hay Creek A B C D ll F G H I J K L M N 0 p Q R s T u V w X y z lMiles ·Above Mouth DISTANCE I 0.14 0.16 0.24 0.25 0.31 0.39 0.46 0.52 0.57 0.63 0.78 0.94 1.09 1.25 1.36 1.39 1.41 1.42 1.46 1.54. 1.56 1.61 1. 74 1.83 1.96 2.02 WIDTH (FEET) 34 60 · 42 42 31 40 28 23 45 31 33 79 33 39 32 40 33 33 30 22 8 43 27 38 52 42 FEDERAL EMERGENCY IV)ANAGEMENT AGENCY KUNG COUNTY, WA ANO INCORPORATED AREAS 1!:¥ ¥ IT·· FLOODWAY SECTION .... (5QUARf ffU) 158 239 99 110 121 150 87 123 165 89 133 143 113 128 89 172 90 111 95 91 68 283 81 170 101 130 MEAN VELOCITY (FEfT PU SECOND) 5.5 3.6 8.8 7.9 7.2 5.8 10.0 7.1 5.3 9.7 6.5 6.1 7. 7 6.6 9.6 4.9 9.5 7.7 8.9 9.3 12.5 2.9 9.9 4.8 8.0 6.3 IUGIJLATOftY 21.0 21.8 23.3 25.7 29.0 32.5 35.8 40.0 41.8 45.3 55,2 64.7 76.4 85.4 93.1 95.6 95.8 96.4 99.8 106.8 112.2 114.2 120.9 125.0 135.8 140.4 BASE FLOOD WATER SURFACE ELEVATION WITHOUT fLOOOWAY I WllH fLOOOWAY (FEET NGVD) 21.0 21.8 23.3 25.7 29.0 32.5 35.8 40.0 41.8 45.3 55.2 64.7 76.4 85.4 93.1 95.6 95.8 96.4 99.8 106.8 112.2 114.2 120.9 125.0 135.8 140.4 21.5 22.2 23.3 25.7 29.2 33.0 35.8 40.6 42.5 45.3 55.2 64.7 76.6 85.4 93.2 96.0 95.8 96.4 99.9 106.9 112.2 115.1 120.9 125.7 135.8 140.5 IFlOODW /AV DA 1r A . MAY CREEK INCREA~ 0.5 0.4 o.o· o.o 0.2 0.5 o.o 0.6 0.7 o.o o.o o.o 0.2 o.o 0.1 0.4 o.o o.o 0.1 0.1 o.o 0.9 o.o 0.7 o.o 0.1 ~ ,--] r 1 r ·1 L-l ,-1 L...:,l r.:;;;;;i ~ !.:..=. "l ~l r --~ '--• ~ ~-:-n ,----t ·-~ -· • ,._ ..: .... -. ·---~~ .. .-::::-· -· ; . --••-•A'•-·• --·--·-. ·-·------··· ·-· ... fflt;•JIIII FLOODING SOURCE FLOODWAY BASE FLOOD WATER SURFACE ELEVATION SECTION MEAN IU.GULATORY WITHOUT I WllH INCREASE FLOOOWAY flOOOWA.Y Cl'I.OSS SECTION 01nANCEt WIDTH ARIA VELOClt'f (FEET) (SQUARE (HU PER FEEi) UCONO) (FHT NGVD) Hay Creek (Cont'd) I AA 3.23 37 124 5.1 266.4 266.4 267.3 0.9 AB 3.34 33 78 8.2 278.3 278.3 278.3 o.o AC 3.49 41 135 4.7 289.6 289.6 290.2 0.6 AD 3.68 40 134 4.8 300,3 300.3 300.3 o.o ~_., __.:, Al! ~.74 15 78 8.2 304.3 304.3 304.5 0.2 c-~ AF 9't< j 3.80 21 80 8.0 306.5 306.5 306.9 0.4 I( 140 .... e,;2.)AG 3,20 . 18 105 5.3 309.2 309.2 310.0 0.8 I AH ( 0, 11 ,.;.') 3.99 53 257 2.2 310.0 310,0 310.7 0.7 :q, -~-,'1£.,.. "'a.) AI ',/q&' & n7 19 92 5.5 3 :o. 2 310.2 311. l 0.9 AJ' G1. 4.13 92 371 1.4 311.5 311.5 312.1 0.6 AK 1 "-li ~ 2 Z 15 303 1. 7 311.5 311.5 312.3 0.8 AL (1 ·+ ,....;) ~j 4.37 J 231 983 0.5 311,8 311.8 312.8 1.0 .' AH \'? . 4.48 96 387 1.3 311.9 311.9 312.9 1,0 AN 1 '12-' 14'8:\ 137 540 0.9 312.1 312 .1 313.l 1.0 I AO 4.68 19 78 6.5 312.5 312.5 313.l 0.6 6 Zfo AP -i;;go 133 559 0,9 313,4 313.4 314.4 1.0 AQ ,5 .12 115 325 1.6 313.8 313.8 314.8 1.0 I I ill-AR 4/1( 5.30 44 120 4.2 315.5 315.5 316,0 0.5 .'L-1(1/-f;Z.) '~ ~. t. 7 12 57 6.5 319.2 319.2 319.2 o.o ' AT 5.56 73 413 0.9 320.3 320.3 321. l 0.8 AU 5. 72 85 444 0,8 320,3 320.3. 321.2 0.9 AV (I-di'"'-') 5.86 184 743 0,5 320.4 320.4 321.4 1.0 AW 6.00 216 491 0.8 320.4 320.4 321.4 1.0 AX s-,s-~ 6.16 50 70 5.3 321.9 321,9 322,2 0.3 khl...,'"1 AY 6.29 100 271 1.4 323.2 323.2 324.2 1.0 -_r AZ 6.44 170 324 1.1 324.0 324.0 324.8 0.8 l,c4\ i 1Hiles Abo, e Mouth/ ! ' c; ~G ('-;:.:'.]='> 'Ok'' ' 1/ ' T FEDERAL EMERGENCY MANAGEMENT AGENCY IFLOOIDWA Y DATA A B KING CO!lJNTY, WA L E AND INCORPORATED AREAS MAY CREEK 4 ' HI Ml 8 .,,. ~ 1$'' J. .ilal g >13311:J AVW S311JOHd OOOH g ;a t, :;..:..j._ ',-,..,.+ ~-;-4-.- ---~.L.l- ...! • . ' =·~· JJ!'fA:; i', , '.+-i..;.'r~ I~ S'l3!1'1 031'1110dll03NI ON'I 'IM 'AlNOOO 9Nrn A:>N3DY 1N3W3D't'N\l'W A:>N3!>1::13W3 1'0'1::13a:u ~ g --r'--H---,J .• ' . . ' ' ~-. i· , . < ti~::iit~ :r w.,..,~,"" ' ' ., t-hi+~ ~ '+t+ .,. 0 N C C C § § 8 .... J "' 'a: ~ ::l ::l ::I > ': > § 8 ' ~ I! I I I I I I I l? C § C !!l .. w §;: "' m .. ~ iig w > w ~ OJ ~ 5 :I : -0 I I I ,., ,:f\1!} :i IOADN l.:13:0 t,:OllYA:113 I_ I • '! N " ~ FLOODING SOURCE FLOODWAY BASE FLOOD WATER SURFACE ELEVATION SECTION MfAN REGULAlORY WITHOUT'" I WITH'" C"OSS\ECflON I OISTAN(t 1 I WIDTH I .... VELOCITY' flOOOWAY FLOODWA'f (ffCI) (SQUARE (FEET PER Ff.El) SECOND) (fEET NGVD) I I I • May Creek I I I I I I I Tributary A 700 61 127 1. 1 329.5 328.0 329.0 B 1,100 78 198 0.7 329.5 328.1 329.1 C 1,600 69 151 0.3 329.5 328.2 329.2 D 1,950 45 92 o.s 329.5 328.2 329.2 E 2,420 51 96 0. 5 329.5 328.3 329.3 F 2,760 13 22 2.1 329.5 328.5 329.4 lFeet Above Mouth 2Elevations Computed Without Consideration of Backwater from May Creek ' FEDERAL EMERGENCY MANAGEMENT AGENCY KING COILJJNTY, WA AND INCORPOl:tATED AREAS FLOODWAY DATA MAY CREEK TRIBUTARY )I t > I INCREASE I I ! 1.0 1.0 1.0 1.0 1.0 0,9 ~ ++ ~ " ~ ~ i.'.~-U:: ~ ~ oli I I I ~ I I ;. 0 I I I I I n 0 " ~ ~! m .. ~ :! m m 0~ m zi 0 ~ .. 0 FEDERAL EMERGENCY MANAGEMENT AGENCY KING COUNTY, WA ANO INCORPORATED AREAS ELEVATIO:-J (FEET NOVO) ~\- " .;. _j +.-4-1 _ ,C-t-H-f I FLOOD PROFILES MAY CREEK 8 i I I I i I I I I I I I I I I .:-. -,,,, ,t, \i- . -2·' : l!!!!!!!I . 150 140 130 g ~ 110 ~ w 'i:,rr-.,!n ·1e -... ii: " 1.4 -- ,_ r:-:-tITT" I t I_· -. ;? :.ij +~,, r , .. 1.6 J.7 1.6 STREAM DISTANCE IN FEET ABOVE MOUTH -liiiil a; -1!!1111 ;+·' C T:9 2.0 ------ LEGEND 500. YEAR FLOOD 100 • YEAR FLOOD 50 • YEAR FLOOD -10 -YEAR FLOOD ~ STREAMBED 6 CROSS SECTION LOCATION ---- "' ... -' ~ I 0. c., ~ i c:, -' .._ > ~ ll < "' ..... z ... ~ c:r:: 0:: w 3:< o C < >"" ~ ._ I-~ z:< > :::, a: u oO z c., .._ ~ c:, 0:: cc z8 w -z: ! ::.C:- ~ C < z: "' <[ ~ ~ 11nP - ,. t ~ • .. • -,.. --.... ojj " !I 0 " ~Ii " ffl ~ a" ~ > :l ffl m " o!l ffl • z5 0 ~ g z 0 N 0 11 I I I i g ~ . 8 < < ffl > m " > • " ~ • !i < ffl > " • g ~ ~ 0 g 8 0 0 N N ~ ~ 0 0 FEDERAL EMERGENCY MANAGEMENT AGENCY KING COUNTY, WA ANO INCORPORATED AREAS ELEVATION (FIEET NGVOI " 0 0 ~: I I I I I I I .. ·i _ -·". ·, .1:•0m1 ~e-rji~~~l -··"'!-·:~-· :::·~:.::/·; .. : i .. :.:.., :., .. :-•-T ... ;' I I -······ ·--· .. ' .............. -.... -···-· ,-. --· .• , .... _ '··!'-~· ·":'" ..... ,.: ... I I I I .rt. :4· ., I -! I I -~ 0 FLOOD PROFILES I MAY CREEK I I ELEVATION !FEET NGVO) w ~ ~ w w 0 N N m 0 m 0 m • " I • :,. I ~ i .. , .. ·,oo • .. ,. I ~ •• ), • i m I • " I • :··;:;~ 0 " " ··i---~ ~ m ·t)-:; • • I 0 .,__;_:·:t:: ;; " • ;@ • z m n m -~-~· l)~.t. 2 I • ;= m 0 • • " m 0 < I m • 0 C " ~ m I m ;., I m I .. s·ri ·r~ oj I I I I m I I .. I I r ffl " m ---n w ~ IS § 8 z 'A I ~ " 0 ' gi ~ .,t .. m m < < -< < .. l: m m •• > > ffl m ~m m ~ ~ > • ~ ~ i~ m ~ ~ ~ ~ .;.....!,.µ~ 0 r r 0 0 8 r r ~--I z 0 0 0 0 0 0 0 0 0 r -·-·-.:;.:t-l--·+1.__. . m . (-.-,.ffi"r'+. -, .. w ~ ~ w w 0 N N • 0 m 0 m I FEDERAL EMERGENCY MANAGEMENT AGENCY FLOOD PROFILES --KING COUNTY, WA "' ,, AND INCORPORATED AREAS MAY CREEK I = ......... -~lll!iillW&ll--""""", ------------· ~-:·, t,~?t .,,.·11*1e r:me:ntttaaHtie@Mf1tt· ... ,.,.,,. ELEVATION (FEET NGVD) -,. ., .. ..+ -· ,, .. ojj I I I I I !:; I I ·- " 0 0 g -8 ~1 iii . 8 .. < < ' .. a0 i m £: < ~ • ~m,. " " I: • i!l m ~ ~ " " ,-,.. "II "II 0 " 8 8 8 § 2 c, O O 0 .. io -FEDERAL EMERGENCY MANAGEMENT AGENCY FLOOD PROFILES -:., "a KING COUNTY, WA ANO /NCORPORA TEO AREAS MAY CREEK I I tit . -H-t. I + -I I I ! I I I I I I I I I I I I I I I I I I I I 7 f-i-' . H-· . ;H-4 + dJ :·:· .. ol " 0 " ;I 60 .. "II ~ >w :!'" = 0~ .. 0 z.; z 0 < .. " " ~ ... 8 0 w w 0 -T -1 .+,:tt ! . I I I I I I I ... m 0 m ~ g § z 0 < < ~ .. " .. m " " " ~ " " ... ~ ~ 0 ... 6 0 8 0 0 0 0 ELEVATION (FEET NGVDl w w ~ " !-' + ·~ .c T, . -~ ::r:~ . -'· ,. I f . ,-· w • 0 ti,;, + i:tl ·_+r+ ·H +· • r +--! '· L -( .;:ti l .T -, H· '-~-1-·-' ·.i.-41.-1- -J:t. •. ' w • ~ -1.·11~:, .. :, >,-, .-\-t-7· ·-.-t-4--+· FEDERAL EMERGENCY MANAGEMENT AGENCY FLOOD PROFILES KING COUNTY, WA AND INCORPORATED AREAS MAY CREEK + . • t-. .. -:;:-.~'" .. ·,-._~,.-. ' -\-. . ---···,··->':.'i.~f.:r-"' .. -,·,-. -·-·· .. .. ········---' .•.. ····-- ;' J I . r I I I e I . . .. -.. . . ., .. ......... ' . . . •, . : .. ,.,i;:-'!_· : §,c. s,cl ··~ ,, :, ... 1 ~-® I \ . ~ )I 3 l ~ ~ l J r-T I 1 l h ~ I g 1 l I I " u~I l ~ I I -_Q . ~ ~la .. " I .l ,_ C i~H l "! l;e ~ ~ -~ &nu ~RI • .. I ~ I 1 ~ I . . l, .... n I .: ~-J I -= - :-cl:lll li I I --., -.. JI!~ JU ' 1117 ~ ii I a ... f .. I I I ... .f ~ ~ ~ -• .;. ';p i •. j J j n ~ -. n -~-• I I ·1_-11:t ~- . -.-.. i . ~ ~ .. . , ' I ,! I .· I. I I . \'!l .. I D ··1 .,ii ~ D a! ~~Bj I• -.. 111 ~,_ i l : 1: I I I I i I '' I I • I I I I I I I 1. I I, I I . .,,_, ·. •::· .,.,.,i,-·• . · . .a .; ... '· ·-r-·\:.•.:·,;~ ·'•; . - !!!Ill ~:t ~~I) ii_ .. , ··: ' .. ' /. '•· : ' ,,...,~ .. . ' .. I :~;· . ., ', 1 \ l \ ii l l' t ,; ' ,1 ' 11;1\ . 1 ~-i -:l.! \ "41 p·t ~1.. --,. -------.. l!: -1--;.. -.... f- ' -=· ~ - ' • f -. ~ : ' • ,e L ' >:C,/;<'' , ... - - - ' . ' !>< b>< I ... ~ ® I ~ I •111 1,11 ~u l;li ~,, 'at· I 1' B I JJ J A I ~ ~' I ' II f jj 11 J j j Id I • I • I I: g • I I 11 Ii I D i 18 u D ! a ' ' .ij·. ,, ., \ ,., I I I I ' ii JA JORDAN/ AVENT a. ASSOCIATES Remarks: May Creek Study Page 7 Remarks included any supplemental information which might help to describe the seqment or subcatchment. Land use for each subcatchment was entered in this column. Other comments included: Street names to aid in locating culverts, clarification of inflow of one segment into another, or the existence of storm sewers or curbs. Please note that streets in this area have changed their names and numbers severa 1 times. Names or numbers 1 isted under remarks are \ those taken from street s1 qns. PROBLEM AREAS The second objective of this study was to photograph and briefly comment on areas subject to serious flooding, erosion or sedimentation. Forty-eiqht color slides and their descriptions are included in Appendix 1. Flooding The problem of flooding along May Creek has been a subject of local concern for several y~ars. Harstad and Associates were contracted in 1965 to plan flood control correctives. Their solution was channelization. This plan was never carried out, mainly for financial reasons. Flooding and high water tables are problems in a 170,000 foot reach of middle and uppper May Creek. More specifically, this area begins about 2,500 feet above the Highway 900 bridge over May Creek; High water problems also exist in the valley which extends southeast toward Issaquah. In this valley ponding is a frequent problem from May Creek almost to the basin divide, a distance of about 3,400 feet. The cause of flooding in this section of the valley is simple: low channel gradient, Flooding problems end where the channel slope again increases, i.e., about 800 feet below the 143th Avenue bridge. Seasonal high water presents a G-7 I I I I I I I I i i i I I I I I I I I I I I I I I I I I I I I I I I I I I I City of R P!ann· enton Ing Divis/on FEB 1 2 lul.l !Rrfrt; May Creek Drainage Improvement Project (9ff 'f@ King County Water and Land Resources Division Stream and Wetland Impact Analysis and Mitigation Plan Prepared by: King County Road Services Division Lindsey Miller, Environmental Engineer Erick Thompson, Senior Environmental Engineer King County Water and Land Resources Division Doug Chin, Supervising Engineer Prepared for: King County Department of Natural Resources and Parks Water and Land Resources Division 20 I South Jackson Street Seattle, WA 98104 Revised September 2011 I I I I I I I I I I I I I I I I I I I Table of Contents Executive Summary .......................................................................................................... iii 1. Introduction ................................................................................................................ I 2. Project Description ..................................................................................................... 2 3. Existing Conditions .................................................................................................... 6 3. I. Geology .......................................................................................................................... 6 3.2. Stream Habitat Conditions .......................................................................................... 6 3.3. Wetlands Conditions .................................................................................................... 9 3.4. Hydraulic Conditions ................................................................................................... 9 4. ImpactAnalysis ........................................................................................................ 13 4. 1. Stream Impacts ........................................................................................................... 13 4.2. Wetland Impacts ......................................................................................................... 16 5. Mitigation Approach ................................................................................................ 19 5. I. Impact Avoidance and Minimization ....................................................................... 19 5.2. Compensatory Mitigation .......................................................................................... 20 5.3. Compensatory Mitigation Goals ............................................................................... 24 5.4. Compensatory Mitigation Objectives ....................................................................... 24 5.5. Compensatory Mitigation Description/ Design ....................................................... 25 6. Performance Standards, Monitoring, Maintenance, and Contingencies ............ 27 6.1. Performance Standards ............................................................................................. 27 6.2. Monitoring .................................................................................................................. 27 6.3. Maintenance ................................................................................................................ 28 6.4. Protection .................................................................................................................... 28 6.5. Contingencies .............................................................................................................. 28 7. References ................................................................................................................ 29 Impact Analysis and Mitigation Plan May Creek Drainage Improvement Plan September 2011 List of Tables Table I: Type and Location of Vegetation Removal.. ...................................................... 14 Table 2: Summary of Stream and Wetland Impacts ......................................................... 17 Table 3: Mitigation Ratios and Proposed Mitigation Areas ............................................. 22 List of Figures Figure I: Project Vicinity Map ........................................................................................... 5 Figure 2: Habitat Unit Proportions ..................................................................................... 8 Figure 3: Existing Riparian and In-Stream Vegetation .................................................... 11 Figure 4: Existing In-stream and Wetland Habitat ........................................................... 12 Appendices Appendix A -May Creek Drainage Improvement Design Plans Appendix B -Long Marsh Creek Restoration Design Plans Impact Analysis and Mitigation Plan ii May Creek Drainage hnprovement Project September 2011 I I I I I hi ll I I I I I I I I I I I I I I I I I I I I I I I I I I I I Executive Summary King County Water and Land Resources Division (WLRD) is proposing to improve flow conditions along May Creek between River Mile (RM) 4.3 and 4.9 in the May Valley located in southeastern King County near the cities of Renton and Newcastle. One large riverine wetland, referred to as May Creek #5 in the King County Wetland Inventory (1990) and three tributaries to May Creek are within the proposed project area. May Creek in this area is nearly flat and flows through large wetlands, many of which are currently used as pastures for horses. Historically, May Valley provided floodwater storage for tributaries draining the upper May Creek basin. May Creek was then ditched into a uniform channel in order to use the floodplain for agricultural purpose. Limited capacity to transport sediment through the flat valley allowed sediment to accumulate. Landowners periodically cleared the stream of sediment and in-channel plants until about the 1940s (King County 1995). Since then, development in the upper watershed to the north and south of May Valley has increased stormwater run-off, leading to an increase in the frequency and duration, but not magnitude, of flooding in May Valley (King County 1995). In addition, invasive non- native vegetation has choked the channel exacerbating the duration of flooding. The flat May Valley reach of May Creek stores stormwater and sediment, releasing both to a higher gradient ravine downstream of the study reach. Slow water and cover from overhanging vegetation in the study reach provide rearing and refuge habitat for fish. To improve flow conditions in May Creek, King County WLRD is proposing to remove accumulated sediment and channel-blocking vegetation in May Creek, as well as reconstruct a portion of Long Marsh Creek to provide sediment storage. As a result of the proposed vegetation and sediment removal, aquatic and wildlife species may be temporarily or permanently degraded in May Creek. Vegetation removal in these areas would degrade riparian habitat by reducing canopy cover, organic inputs, prey sources, bank stability, and future large wood recruitment. May Creek would experience localized hydraulic changes within the project area when the willow, reed canarygrass and sediment removal occurs. Riparian and in-stream habitat associated with Long Marsh Creek would also be temporarily degraded as a result of the channel reconstruction. King County has designed the project to avoid and minimize impacts to wetlands, streams, and buffers to the greatest extent possible. Impacts that cannot be avoided and minimized must be compensated for by constructing mitigation. The mitigation goal for this project is to achieve no overall net loss in habitat functions in the May Creek sub- basin. This would be accomplished with out-of-kind mitigation by enhancing approximately five acres of riparian buffer and riverine wetland. The enhancements would include planting native riparian/wetland vegetation, reed canary grass suppression, Impact Analysis and Mitigation Plan iii September 2011 May Creek Drainage Improvement Project construction of two off-channel alcoves, placement of large woody debris (76 pieces), and installation of snags in the wetland. The mitigation is considered out-of-kind, because the majority of the impacts are to in-stream habitat, while the proposed mitigation enhances riparian and wetland habitat. Impact Analysis and Mitigation Plan iv September 2011 May Creek Drainage Improvement Project I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 11 1. Introduction King County Water and Land Resources Division (WLRD) proposes to improve in- stream flow of May Creek in May Valley between about RM 4.3 and 4.9 in southeastern King County, near the cities of Renton and Newcastle (Figure l) Sections 2 and 3, Township 23N, Range 5E. Sediment accumulation and in-stream vegetation (e.g., reed canarygrass and willows) throughout the valley reach of May Creek have been gradually decreasing channel flow capacity, causing a backwater effect. This is increasing the duration of flooding in actively used horse pastures on adjacent rural residential properties, with standing water and wet pastures now persisting into the summer months. The goal of this project is to reduce the duration of flooding on these properties at both the start and end of the wet season by removing in-stream channel obstructions. This effort should help alleviate the duration of localized flooding on adjacent properties during low to moderate storm events and should allow the pastures to drain more effectively when flooding does occur. The reach proposed for improvement begins on the south side of SE May Valley Road about 0.1 mile downstream of 148th Avenue SE in Renton and includes the main stem of May Creek extending upstream about 2,900 feet to a point just downstream from the confluence of May Creek with Indian Meadow Creek. One large riverine wetland, May Creek #5, May Creek, and three tributaries to May Creek are within the proposed project area. The project area is located in the Watershed Resource Inventory Area (WRIA) 8 Lake Washington Basin. The existing conditions of streams and wetlands are described in more detail in Section 3. The King County current zoning classification in the majority of the project area is RA-5 and RA-I 0, rural residential with future development limited to rural uses with maximum densities of one house per five acres and ten acres, respectively. There is also a designated open space tract on the west side of 148th Avenue SE within the City of Renton where the majority of the compensatory mitigation would be constructed. Currently, small horse farms and open space are the primary land uses in the project area. A large portion of the riverine wetland in May Valley was converted to agriculture in the early 1900s, and May Creek was regularly dredged to support agriculture. About 50 years ago, regular dredging ceased in May Creek, and agricultural production has ceased as a result of increased flooding. The small farms in the project area are flooded during most months of the year. Many of these pastures are located within the delineated wetland boundary. Impact Analysis and Mitigation Plan May Creek Drainage Improvement Plan September 2011 The purpose of this report is to analyze the potential stream and wetland impacts associated with the project, and to describe how the mitigation has been designed to avoid, minimize, and compensate for these impacts. 2. Project Description The project proposal consists of four components: vegetation removal, sediment removal, sediment management, and stream/wetland mitigation. The vegetation/sediment removal and the sediment management would negatively impact existing in-stream fish habitat and riparian buffer functions, so mitigation has been proposed to offset these impacts. The project components are described below. Vegetation Removal: The first component of the project includes removal of flow obstructing in-stream vegetation and debris that have been identified as choking the channel and creating a backwater effect, causing flooding on adjacent properties during small storm events. Invasive reed canarygrass is the dominant vegetation that would be removed from the channel and banks. In addition, willows, located in multiple locations throughout the project area, currently have branches crossing over the stream channel at selected locations within the winter flow elevation, further contributing to the backwater effect. A portion of the willows that are identified as obstructing flow would also be removed. The willows on the west side of 148th Avenue SE would be primarily removed by hand, but some small, hand-held, mechanized machinery may be used to assist. Willows and reed canarygrass on the east side of 148th Avenue SE would be removed in conjunction with the sediment removal using machinery, most likely a low impact spyder hoe, operated from the stream bank. Prior to removal of in-stream vegetation using machinery, the stream would be diverted around the construction site and erosion and sediment control best management-practices would be used during construction to minimize temporary downstream water-quality impacts (King County July 2011 ). The impacts associated with the vegetation removal are described in Section 4. Sediment Removal: Sediment would be removed from the stream channel using machinery, most likely a low impact spyder hoe, operated from the stream bank. The stream would be diverted around the construction site and erosion and sediment control best management practices would be used during construction to minimize temporary downstream water-quality impacts (King County July 2011 ). Construction techniques, such as, using existing access roads and requiring all machinery to be tracked or rubber tired, would be used to minimize temporary impacts to adjacent wetlands. Sediment would be first placed in on-site soil drying areas and then would be disposed of on-site in a stable, non-erosive manner outside flood prone and sensitive areas. The impacts associated with the sediment removal are described in Section 4. Sediment Management: To increase the longevity of the project, 300 feet of the Long Marsh Creek channel and its confluence with May Creek would be reconstructed to allow Impact Analysis and Mitigation Plan 2 September 2011 May Creek Drainage Improvement Project I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I sediment to drop out more naturally prior to reaching the mainstem of May Creek. This reconstruction would include an approximately I 00 foot long side channel adjacent to May Creek. Based on the sediment yield rate in Long Marsh Creek over the past eight years (2002 to 2010), the channel reconstruction would provide approximately 70 years of sediment storage capacity. Stream/Wetland Mitigation: The final component of the project includes providing mitigation to avoid, minimize, and compensate for in-stream and wetland habitat impacts. The following mitigation would be implemented and is further described in Section 5: o During construction, the stream flow would be diverted around the work area, and in- water work would only be conducted during summer low flow when fish are less likely to be present. King County staff would be onsite during construction to monitor water quality. Water quality monitoring and protection procedures are described in the project's Construction Water Quality Protection and Monitoring Plan (King County July 2011 ). o Construction techniques, such as using existing access roads and requiring all machinery to be tracked or rubber tired would minimize disturbance to existing vegetation. In addition, direct access to the stream channel by equipment would be in specific areas where vegetation disturbance can be minimized and removal of mature trees can be avoided. Excavation would likely be performed by spyder hoe, which is excavator designed for rough terrain and low impact operation in sensitive areas. Stream access points would be limited to avoid removal of mature trees. o Prior to sediment removal, approximately 60 linear feet of streambed gravels located in May Creek (Station 15+60 to 16+ 30) near the confluence of Long Marsh Creek, would be removed and saved so that they can be placed back in the same reach of stream channel after the sediment removal is complete. o A buffer of native vegetation (primarily wetland vegetation) would be restored for approximately 15 feet on each side of May Creek east and west of 148th Avenue SE for a total of approximately two acres. This buffer is intended to minimize reed canarygrass infestation and to compensate for the cover that would be lost by removing flow-obstructing willows and reed canarygrass. Native vegetation would be planted in areas where, under existing conditions, only reed canarygrass exists. In most of the project area, the regulatory stream buffer is contained within the delineated wetland boundary, which means that stream buffer enhancement could also be considered wetland enhancement. Fencing would be installed around the planting areas to eliminate livestock access to the newly planted areas and to the stream. Impact Analysis and Mitigation Plan 3 September 2011 May Creek Drainage Improvement Project o In addition to the two acres of riparian buffer planting, an additional three acres of wetland enhancement would be constructed on the west side of 148th Avenue SE to compensate for impacts associated with the sediment removal. This enhancement would include construction of approximately 0.24 acres of off-channel wetland alcoves along May Creek, reed canarygrass suppression, placement oflarge woody debris (LWD) (76 pieces), two snags, and planting native vegetation. This would provide out-of-kind mitigation for impacts to in-stream habitat functions by enhancing wetland habitat functions. o King County would protect the mitigation areas in perpetuity by recording a conservation easement, or similar document, on the title of each property. Impact Analysis and Mitigation Plan 4 September 2011 May Creek Drainage Improvement Project I I ll [j I I I I I I I I May Creek Drainage Improvement Project Project Vicinity e StudyArea o Mile Markers Stream Incorporated Areas Cougar Mounta in Wi ldland Park March 2010 tQ King County 0 95 190 760 .... 111:::::::::::::::1111 .. 1111::::::::::::::::i Fee 380 570 The iRQnnab'I ~ on U.. map MS been~ by tang Cowlty .., from• vanety rJ ec:uoes and «s sw,ec:t lo ---l'Ong Cowuy mak• no represen&auona or wwranties, axp,a1 or mplied, .. to 10:wecy, ccmpleten.a, lwneliness.. or rights IO ttw use rJ tud'I ~fonnation. This docum&nl it nol lnlanded fo, UM N I ll.UWY product. ""1gCowlly-notbo-lcrMy-l,opodal, __ "' ____ .... rQ lnited ID, Qt ,....,..s or mt ptQltl, 1"Uling iom fte use or~ d fte ir*wmation contained a, HI rntp. My.-of u. mep ot Information on lt'i1 map is s,rot.bUd °'"'pl by w'"1M --d l<lng Cour<y Figure 1 ,1~~Mayo.kAeaorllllcn( ..... l I I I I I I I I I I I I I I I I I I I 3. Existing Conditions This section describes the existing geology, stream, wetland and hydrologic conditions in the project area. 3.1. Geology The wide and relatively flat May Valley (RM 3.9 to RM 7.0) was created by glacial ice- melt runoff and is part of the "Kennydale Channel". The recessional phase of the Vashon Glaciation created a series of drainage channels. As the Vashon Glacier receded, the outlet drainage continued to shift to the northwest through the Cedar Grove, Kennydale, and Eastgate Channels (now occupied by I-90). The valley is underlain by recent alluvium and wetland deposits over recessional outwash deposits and compacted glacial ti l l. These recent deposits overlie Eocene Tukwila Formation. The Tukwila Formation is composed of volcanic tuff, fine-grained volcanic sandstone and volcanic tuff-breccia. The formation is reported to outcrop east of 146th A venue Southeast and forms a physical boundary between the downstream ravine and May Vall ey upstream. The compacted glacial materials and bedrock are resistant to erosion by May Creek in the valley. Surface water infiltration into the glacial till and bedrock is limited du e to low permeabi lity. 3.2 . Stream Habitat Conditions May Creek is about 11.3 kilometers (seven miles) long, with about 30.6 km (19 miles) of tributary streams, draining about 38 .3 square kilometers (14 square miles). It is classified as a Type F Water (fish present) under the King County Critical Area Code, requiring a 50.3 m (165-ft) regulatory buffer. Under City of Renton Critical Area Code, May Creek is considered a Class 2 stream (salmonid bearing) requiring a 100-foot buffer. Three tributary creeks (Indian Meadow Creek, Long Marsh Creek, and Greenes Creek) join the mainstem of May Creek in the project area , which flows through the valley and into a narrow, erosive canyon before flowing into Lake Washington. May Valley was historically an area of sediment deposition and flood storage, and the stream channel braided through extensive wetlands. The stream was put in a ditched single-strand channel so the surrounding floodplain could be used for agriculture and was regul arly dredged until about 50 years ago. The May Valley provides stormwater storage, which helps control erosion downstream of the project area (King County 200 l , Anchor QEA 2010). Riparian areas adjacent to May Creek are mostly wetland that has been converted to agriculture (wetlands are described in Section 3.3). These riparian areas are primarily dominated by reed canarygrass; however, the stream in the western reach of the project is beginning to revert to more natural conditions due to the presence of an undisturbed buffer of willows (Salix spp.) and red alder (A/nus rubra) about 50 to 75 feet wide. These woody plants stabilize stream banks, provide shade, food, and hiding cover, and increase in-stream Imp act An aly sis and Miti gati on Pl an 6 Se pt emb er 2011 May Creek Draina ge Impro ve ment Proj ec t habitat complexity by providing hard points that create a mixture of slow-water and fast- water areas. The channel in the upstream portion of the project reach lacks woody plants and is almost exclusively vegetated with reed canarygrass. The channel in this reach is more uniform and has filled in with sediment so it is more prone to flooding . Figure 3 shows the vegetation units in the project area. In-stream habitat in the surveyed reach of May Creek is influenced by riparian plant communities. Aquatic habitat is more complex in places where the riparian corridor has woody plants, such as willows, engaged with the stream channel and connected floodplain. Overhanging or rooted willow branches or stems provide cover and hard points necessary for bedform complexity, producing both turbulent and non-turbulent flow areas, and creating six of the nine pools identified in the project area (King County 2010b). Terrestrial insects falling from the willow canopy provide food for fish living in the stream, and fallen leaves provide nutrients. Areas with no woody riparian plants are much more uniform and tend to have accumulations of fine sediments in the channel. May Creek within the surveyed stream reach was dominated by slow-water glides (Figure 2). Pools made up approximately 25 percent of the surface area in Reaches One and Two, approximately ten percent of the area in Reach Three, and approximately 13 percent of the area over the entire surveyed reach; no pools were present in Reach Four. All of the pools were lateral scour pools except one mid-channel pool in Reach One. Fast water was limited to a single low-gradient riffle at the 1481h Avenue SE Bridge, and a couple of pool tail-outs in Reach One. Impa ct An a lysis and Miti gation Plan 7 Se ptembe r 2011 May Cree k Draina ge Improvement Proj ec t I I I I I ,, I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I s 0 I- ~ 0 -C: a., ~ a., Q. 100 80 60 40 74 68 90 85 10 Reach 1 Reach 2 Reach 3 Reach 4 Entire OGlide •Pool m Riffle Figure 2: Habitat Unit Proportions , as surface area (m2). Dotted area is fast water; solid area is slow water. Water flow s from Reach 4 to Reach 1. Many of the areas in ventoried as g lide during the low-flow s tream survey in August 2010 had both turbulent and non-turbulent flow during the February 2010 stream reconnaissance. This is most appa rent in Reach Two, which h as a relatively wide, m ature, willow-dominated riparian corridor. Dense willow branches cross the stream channe l throughout this reach, functioning like a debris complex and creating numerous backwater areas during higher flow s. This r each i s well-connected with its flo odplain, and some floodplain terracing is present, which a lso increases habitat complexity during hi g he r flow s . The wider forested riparian area has shad ed out reed can arygrass. In areas where reed canarygrass dominat es, s u ch as Reach Four , the channel tends to b e deeper and has muc h thicker accumul at ion s of fine sedime nt. May Creek historically was an imp ortant salmon stream in the Lake Washington Basin (WDF 1975). The stream supported five species of salmonids: Chinook (Oncorhyncus Ts c hawytscha), sockeye (0. nerka), and coho (0. kisutch) salmon, and rainbow/steelhead (0. mykiss) and cutthroat (0. clarki) trout (King County 1995). Salmon still use the stream and its tributaries even though their numbers have decreased (King County 1995). C hinook and sockeye salmon are found in the lower reaches of May Creek and in May Canyon ; they most likely do not travel upstream as far as May Valley (King County 1995). Co ho salmon and rainbow/stee lhead and cutthroat trout rear in May VaJley and u se it as a travel corri dor to upstream spawning habitat in the North Fork, Cabbage and Country Creeks, and Tributary 0291A (upstream of proposed project) (King County 1995). Imp ac t Analys is and Miti ga tion Pl an 8 September 2011 May Cree k Drain age Improve ment Proj ec t Although we did not conduct a formal census offish in the surveyed reach of May Creek, we observed many schools of salmonids during the August 2010 habitat survey (Appendix B). Most schools were about 10 to 30 individual juvenile fish, and appeared to have both coho salmon and trout. 3.3. W etlands Conditio ns One large riverine wetland, referred to as May Creek #5 in the King County Wetland Inventory (1990), is located in the project study area. This wetland is about 140 acres in total size; about 25 acres are contained in the project study area. The portion of the wetland located in the project area was delineated by King County wetland biologists in early 2010, and the entire wetland was also rated at that time (King County 2010a). May Creek #5 is a Category II riverine wetland with a 110-foot buffer under the King County Critical Area Code. The majority of the wetland is located in unincorporated King County; however, the portion west of 148th Avenue SE is located in the City of Renton. Under the City of Renton Critical Area Code this is a Category 3 wetland with a regulatory buffer width of 25 feet. The wetland is located in the 100-year floodplain of May Creek. Primary sources of hydrology to the May Creek #5 wetland are a combination of overbank flooding and a high groundwater table. While the wetland still received a high rating, it has been degraded over the years by adjacent farming and agriculture. Many areas of the wetland are actively mowed and used for grazing horses and other livestock. In the farm areas on the north si de of the wetland, the wetland boundary closely follows a line of fill that appears to have been placed in the wetland over the years to allow pasturing. On the south side of the wetland, the wetland boundary more closely follows valley topography, and multiple groundwater seeps were visible on the valley walls at higher elevations. In the majority of the wetland not regularly mowed and maintained as pasture, the dominant vegetation was reed canarygrass, which grew as thick blankets with almost 100-percent coverage. The only unmowed areas without reed canarygrass were in the scrub- shrub/forested components of the wetland near May Creek where the reed canarygrass was shaded out. The width of the scrub-shrub/forested buffer along the stream was about 50 to 75 feet in areas where the reed canarygrass was shaded out (i.e., 25 to 37 feet wide on each side of the stream). 3.4. Hydraulic Conditions May Creek valley experiences out of bank flooding that last several days to weeks at a time on a routine basis every wet season. The stream course is essentially in a bowl for approximately 2100 feet (river mile 4.6 to 5.0) between a footbridge upstream of Parcel #0223059005 property down to Long Marsh Creek confluence where a sediment delta has built up, just upstream of another footbridge. Long Marsh Creek is primarily a forested basin with steep gradients. This characteristic gives the tributary the ability to Impa ct Analysi s and Mitigation Plan 9 September 20 11 May Creek Drainage Improvement Project I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I deposit gravels large enough such that May Creek is not capable to redistribute gravels downstream. Thus stream bed elevations at this location rise as more gravel is deposited. This accumulation causes May Creek to backwater upstream causing more deposition of fines and decaying vegetation subsequently reducing conveyance capacity and increasing frequency of valley flooding. Two types of models were used to perform hydraulic and hydrologic analyses for current conditions and proposed drainage improvement scenarios, HEC-RAS for hydraulics and HSPF (Bicknell 2005) for hydrology. Both models used were adapted from existing models and updated to reflect current conditions. HEC-RAS (USACE 2008) was used to evaluate channel conveyance capacities and flooding inundations, while HSPF was used to provide statistical measures of durations and magnitudes of events used for defining boundary conditions in the HEC-RAS model. The analysis shows that during mean annual flows (8.6 cfs through the study area), control points include vegetation choking points in the wetland downstream of 148th Avenue SE bridge and mildly so upstream of 148th Avenue SE and gravel deposition where Long Marsh Creek enters into May Creek at approximately river mile 4.64, just upstream of a footbridge. This high point of gravels controls the water surface elevation upstream approximately for 2000 feet to a footbridge located approximately at river mile 5.04. Similarly for flows above the one year event, Long Marsh Creek again controls water surfaces upstream for the same reach length. Downstream of 148th A venue SE, hydraulic model runs show the natural constriction change from open wetland on valley floor to well defined channel entering into the ravine controls storm events flows of one year return interval and greater. Removal of vegetation choke points in the wetland produce a few tenths of a foot change in water surface, within the range of model accuracy and very small amount of lost storage, this natural land form constriction downstream of the proposed restoration channel activities is the control for erosion in the ravine . Flows below the one year flood event would have a slightly longer duration but not higher velocity. The flows at these lower events are below levels that cause channel erosion below May Valley (AnchorQEA, 2010). Impac t Ana lysis a nd Miti gation Pla n 10 Septe m ber 2011 M ay Creek Dra in age Imp roveme nt Project I I I I I I I I I I I •• I I I I I I I 3. Existing Conditions This section describes the existing geology, stream, wetland and hydrologic conditions in the project area. 3.1. Geology The wide and relatively flat May Valley (RM 3.9 to RM 7.0) was created by glacial ice- melt runoff and is part of the "Kennydale Channel". The recessional phase of the Vashon Glaciation created a series of drainage channels. As the Vashon Glacier receded, the outlet drainage continued to shift to the northwest through the Cedar Grove, Kennydale, and Eastgate Channels (now occupied by 1-90). The valley is underlain by recent alluvium and wetland deposits over recessional outwash deposits and compacted glacial till. These recent deposits overlie Eocene Tukwila Formation. The Tukwila Formation is composed of volcanic tuff, fine-grained volcanic sandstone and volcanic tuff-breccia. The formation is reported to outcrop east of 1461h Avenue Southeast and forms a physical boundary between the downstream ravine and May Valley upstream. The compacted glacial materials and bedrock are resistant to erosion by May Creek in the valley. Surface water infiltration into the glacial till and bedrock is limited due to low permeability. 3.2. Stream Habitat Conditions May Creek is about 11.3 kilometers (seven miles) long, with about 30.6 km (19 miles) of tributary streams, draining about 38.3 square kilometers (14 square miles). It is classified as a Type F Water (fish present) under the King County Critical Area Code, requiring a 50.3 m (165-ft) regulatory buffer. Under City of Renton Critical Area Code, May Creek is considered a Class 2 stream (salmonid bearing) requiring a I 00-foot buffer. Three tributary creeks (Indian Meadow Creek, Long Marsh Creek, and Greenes Creek) join the mainstem of May Creek in the project area, which flows through the valley and into a narrow, erosive canyon before flowing into Lake Washington. May Valley was historically an area of sediment deposition and flood storage, and the stream channel braided through extensive wetlands. The stream was put in a ditched single-strand channel so the surrounding floodplain could be used for agriculture and was regularly dredged until about 50 years ago. The May Valley provides stormwater storage, which helps control erosion downstream of the project area (King County 200 I, Anchor QEA 20 I 0). Riparian areas adjacent to May Creek are mostly wetland that has been converted to agriculture (wetlands are described in Section 3.3). These riparian areas are primarily dominated by reed canary grass; however, the stream in the western reach of the project is beginning to revert to more natural conditions due to the presence of an undisturbed buffer of willows (Salix spp.) and red alder (A/nus mbra) about 50 to 75 feet wide. These woody plants stabilize stream banks, provide shade, food, and hiding cover, and increase in-stream Impact Analysis and Mitigation Plan 6 September 2011 May Creek Drainage Improvement Project habitat complexity by providing hard points that create a mixture of slow-water and fast- water areas. The channel in the upstream portion of the project reach lacks woody plants and is almost exclusively vegetated with reed canarygrass. The channel in this reach is more uniform and has filled in with sediment so it is more prone to flooding. Figure 3 shows the vegetation units in the project area. In-stream habitat in the surveyed reach of May Creek is influenced by riparian plant communities. Aquatic habitat is more complex in places where the riparian corridor has woody plants, such as willows, engaged with the stream channel and connected floodplain. Overhanging or rooted willow branches or stems provide cover and hard points necessary for bedform complexity, producing both turbulent and non-turbulent flow areas, and creating six of the nine pools identified in the project area (King County 20 !Ob). Terrestrial insects falling from the willow canopy provide food for fish living in the stream, and fallen leaves provide nutrients. Areas with no woody riparian plants are much more uniform and tend to have accumulations of fine sediments in the channel. May Creek within the surveyed stream reach was dominated by slow-water glides (Figure 2). Pools made up approximately 25 percent of the surface area in Reaches One and Two, approximately ten percent of the area in Reach Three, and approximately 13 percent of the area over the entire surveyed reach; no pools were present in Reach Four. All of the pools were lateral scour pools except one mid-channel pool in Reach One. Fast water was limited to a single low-gradient riffle at the 148 1h Avenue SE Bridge, and a couple of pool tail-outs in Reach One. Impact Analysis and Mitigation Plan 7 September 2011 May Creek Drainage Improvement Project I I I I I bl a I II I I I I I I I I I I I I I I I I I I I I I I I I I I I I Cll I!! < Cl) CJ ~ ::I (/) JS 0 1--0 -C: Cl) ~ Cl) CL 100 80 60 40 20 74 68 90 10 23 25 Reach 1 Reach 2 Reach 3 Reach 4 85 Entire oGlide oPool D Riffle Figure 2: Habitat Unit Proportions, as surface area (m2). Dotted area is fast water; solid area is slow water. Water flows from Reach 4 to Reach I. Many of the areas inventoried as glide during the low-flow stream survey in August 2010 had both turbulent and non-turbulent flow during the February 2010 stream reconnaissance. This is most apparent in Reach Two, which has a relatively wide, mature, willow-dominated riparian corridor. Dense willow branches cross the stream channel throughout this reach, functioning like a debris complex and creating numerous backwater areas during higher flows. This reach is well-connected with its floodplain, and some floodplain terracing is present, which also increases habitat complexity during higher flows. The wider forested riparian area has shaded out reed canarygrass. In areas where reed canarygrass dominates, such as Reach Four, the channel tends to be deeper and has much thicker accumulations of fine sediment. May Creek historically was an important salmon stream in the Lake Washington Basin (WDF 1975). The stream supported five species of salmonids: Chinook ( Oncorhyncus Tschawytscha), sockeye (0. nerka), and coho (0. kisutch) salmon, and rainbow/steelhead (0. mykiss) and cutthroat (0. c/arki) trout (King County 1995). Salmon still use the stream and its tributaries even though their numbers have decreased (King County 1995). Chinook and sockeye salmon are found in the lower reaches of May Creek and in May Canyon; they most likely do not travel upstream as far as May Valley (King County 1995). Coho salmon and rainbow/steelhead and cutthroat trout rear in May Valley and use it as a travel corridor to upstream spawning habitat in the North Fork, Cabbage and Country Creeks, and Tributary 029 lA (upstream of proposed project) (King County 1995). Impact Analysis and Mitigation Plan 8 September 2011 May Creek Drainage Improvement Project Although we did not conduct a fonnal census of fish in the surveyed reach of May Creek, we observed many schools of salmonids during the August 20 l O habitat survey (Appendix B). Most schools were about lO to 30 individual juvenile fish, and appeared to have both coho salmon and trout. 3.3. Wetlands Conditions One large riverine wetland, referred to as May Creek #5 in the King County Wetland Inventory (1990), is located in the project study area. This wetland is about 140 acres in total size; about 25 acres are contained in the project study area. The portion of the wetland located in the project area was delineated by King County wetland biologists in early 2010, and the entire wetland was also rated at that time (King County 20 lOa). May Creek #5 is a Category II riverine wetland with a 110-foot buffer under the King County Critical Area Code. The majority of the wetland is located in unincorporated King County; however, the portion west of 148th Avenue SE is located in the City of Renton. Under the City of Renton Critical Area Code this is a Category 3 wetland with a regulatory buffer width of 25 feet. The wetland is located in the 100-year floodplain of May Creek. Primary sources of hydrology to the May Creek #5 wetland are a combination of overbank flooding and a high groundwater table. While the wetland still received a high rating, it has been degraded over the years by adjacent fanning and agriculture. Many areas of the wetland are actively mowed and used for grazing horses and other livestock. In the fann areas on the north side of the wetland, the wetland boundary closely follows a line of fill that appears to have been placed in the wetland over the years to allow pasturing. On the south side of the wetland, the wetland boundary more closely follows valley topography, and multiple groundwater seeps were visible on the valley walls at higher elevations. In the majority of the wetland not regularly mowed and maintained as pasture, the dominant vegetation was reed canarygrass, which grew as thick blankets with almost 100-percent coverage. The only unmowed areas without reed canarygrass were in the scrub- shrub/forested components of the wetland near May Creek where the reed canarygrass was shaded out. The width of the scrub-shrub/forested buffer along the stream was about 50 to 75 feet in areas where the reed canarygrass was shaded out (i.e., 25 to 37 feet wide on each side of the stream). 3.4. Hydraulic Conditions May Creek valley experiences out of bank flooding that last several days to weeks at a time on a routine basis every wet season. The stream course is essentially in a bowl for approximately 2100 feet (river mile 4.6 to 5.0) between a footbridge upstream of Parcel #0223059005 property down to Long Marsh Creek confluence where a sediment delta has built up, just upstream of another footbridge. Long Marsh Creek is primarily a forested basin with steep gradients. This characteristic gives the tributary the ability to Impact Analysis and Mitigation Plan 9 September 2011 May Creek Drainage Improvement Project I I I I I I ll I I I I I I I I I I I I I I I I I I I I I I II I I deposit gravels large enough such that May Creek is not capable to redistribute gravels downstream. Thus stream bed elevations at this location rise as more gravel is deposited. This accumulation causes May Creek to backwater upstream causing more deposition of fines and decaying vegetation subsequently reducing conveyance capacity and increasing frequency of valley flooding. Two types of models were used to perform hydraulic and hydro logic analyses for current conditions and proposed drainage improvement scenarios, HEC-RAS for hydraulics and HSPF (Bicknell 2005) for hydrology. Both models used were adapted from existing models and updated to reflect current conditions. HEC-RAS (USACE 2008) was used to evaluate channel conveyance capacities and flooding inundations, while HSPF was used to provide statistical measures of durations and magnitudes of events used for defining boundary conditions in the HEC-RAS model. The analysis shows that during mean annual flows (8.6 cfs through the study area), control points include vegetation choking points in the wetland downstream of 148th Avenue SE bridge and mildly so upstream of 148th Avenue SE and gravel deposition where Long Marsh Creek enters into May Creek at approximately river mile 4.64, just upstream of a footbridge. This high point of gravels controls the water surface elevation upstream approximately for 2000 feet to a footbridge located approximately at river mile 5.04. Similarly for flows above the one year event, Long Marsh Creek again controls water surfaces upstream for the same reach length. Downstream of 148th Avenue SE, hydraulic model runs show the natural constriction change from open wetland on valley floor to well defined channel entering into the ravine controls storm events flows of one year return interval and greater. Removal of vegetation choke points in the wetland produce a few tenths of a foot change in water surface, within the range of model accuracy and very small amount of lost storage, this natural land form constriction downstream of the proposed restoration channel activities is the control for erosion in the ravine. Flows below the one year flood event would have a slightly longer duration but not higher velocity. The flows at these lower events are below levels that cause channel erosion below May Valley (AnchorQEA, 2010). Impact Analysis and Mitigation Plan 10 September 2011 May Creek Drainage Improvement Project May Creek Drainage Improvement Project Legend /'v' Willow (893') /'v' Willow/RCG Mi x (580') /'v' Reed Canarygrass (RCG ) (1360') 0 N + December 2010 tQ King County 75 150 300 450 The information included on this map has been compiled by King County staff from a variety of sources and is subject to change wilhout notice. 600 Feet King County makes no representrtions Of warranties, express or implied. as to accuracy, completeness. timeHness, or rights to the use of such info,ma1ion. T his document Is not intended for use as a survey product King County shal not be liable for any general. special ndirect. inadental, Of consequential damages including, but not imited to, lost revenues Of lost profits resulting from the use Of misuse of the information contained on this map. Any sale of this map or information on this map ,s prohibited except by 'Mitten permission of King County. Figure 3 Existing Reparian and In-Stream Vegetation POIR--!205·~ .... °"""·--IS --------------~--~~ May Creek Drainage Improvement Project Legend • Study Area o River Mile Habitat Units /\/GLD /\/LGR /\/LSP /\/MCP /\/T /"-/ Streets /"-/ Streams Wetlands • Cougar Mountain Wildland Park N + December 2010 tQ King County 0 90 180 360 540 720 ........ a:::=:=:=::::i ........ 11::::=:=:=::::i Feet The information included on this map has been compiled by King County stat! from a variety of sources and is subject to change wtilout notice. King County makes no representations or warranties, express or imptied, a s to accuracy, completeness. timeliness. or rights to the use of such information This document is not intended for use as a survey product King County shall not be liable for any general. special indirect inadental, or consequential damages including, but not imited to, lost revenues or lost profits resulting from the use or misuse of the information contained on this map. Any sale of this map or onformation on this map is prohibited except by written permission of King County. Figure 4 PO tR.o-o,,~~t'Af.l205~DMRP~Owlc~MllOl'IIOn(M,ttr~'GtS I I I I I I I I I I I I I I I I I I I 4. Impact Analysis The unavoidable stream and wetland impacts associated with the project are described in this section. 4.1. Stream Impacts As a result of vegetation and sediment removal, the aquatic and terrestrial habitat features within May Creek and its buffer may be temporarily or permanently degraded. Vegetation removal in these areas would degrade riparian habitat by reducing canopy cover, organic inputs, prey sources, bank stability, and future large wood recruitment. The stream would experience localized hydraulic changes within the project area when the willow and reed canarygrass removal and sediment removal occurs. These changes have the potential to modify fish habitat in May Creek, such as the locations and depths of pools, quantity and quality of coho and trout rearing and refuge habitat, and quantity of local spawning gravel. Impacts to Long Marsh Creek as a result of the sediment management activities include temporarily disturbed in-stream habitat and riparian buffer. These impacts are described in more detail below and are summarized in Table 2 at the end of this section. 4.1.1. Impacts from Sediment Removal Sediment removal would occur in May Creek from Station 5+40 to 26+ 26 (2,086 linear feet) and would have both short-and long-term effects on the stream. As part of the sediment removal, the stream channel would be excavated to a uniform elevation of 308 feet. The following list summarizes the potential impacts that could occur as part of the sediment removal operations: o removal of stream bank and aquatic vegetation o removal, release, or rearrangement of silts and sediments o reduction of water quality 1. remobilization of contaminants (if any were to exist in project area) 2. increased turbidity 3. increased erosion and sedimentation o alteration of fish habitat 1. elimination of habitat type (channel complexity) 2. alteration of fish-spawning habitat 3. alteration ofbenthic habitat 4. disruption or removal of benthic communities Several factors influencing the magnitude of the effects of dredging-type activities such as this include: size of the dredging operation, frequency of dredging, stream channel size and depth, size of material, background levels of water and sediment quality, Impact Analysis and Mitigation Plan 13 September 2011 May Creek Drainage Improvement Project suspended sediment, turbidity, stream velocity, design of final contours, and stability of channel up-and down-stream from the dredging operation. The list of impacts above may occur at May Creek. Sediment removal would occur along 72 percent of the proposed project area and would impact in-stream habitat, spawning habitat, water quality, and alter the timing and magnitude of silt and sediment migration. Sediment removal would have its biggest impact on Reach Two because this reach is well-connected with its floodplain, has some floodplain terracing, and is well vegetated. Sediment removal would reduce the stream's floodplain connection during smaller flow events and would remove functioning riparian vegetation. Sediment removal in Reach Three, which includes the alluvial fan of Long Marsh Creek, would temporarily disturb spawning gravels in May Creek. 4.1.2. Impacts from Vegetation Removal In combination with sediment removal impacts, the stream would also be negatively impacted by removal of in-stream and bankside willows and reed canarygrass throughout the entire project area. Table 1 describes the type and location of vegetation removal associated with this project. Table 1: Type and Location of Vegetation Removal Type of Vegetation Removal Station Station From To Mav Creek In-stream Willow Prunin!! (hand removal) 0+00 0+30 In-stream Reed Canarv Grass Removal (mechanized) 0+30 0+70 In-stream Willow Prunin!! (hand removal) 0+70 1+50 In-stream Reed Canary Grass Removal ( mechanized) 1+50 3+00 In-stream Willow Prunin!! (hand removal) 3+00 4+50 In-stream Reed Canarv Grass Removal (mechanized) 4+50 4+90 In-stream Willow Pruning (hand removal) 4+90 5+40 In-stream Ve!!etation and Sediment Removal ( mechanized) 5+40 26+26 In-stream Reed Canarv Grass Removal ( mechanized) 26+26 29+00 Lon!! Marsh Creek Rioarian Buffer Clearin!! for Channel Reconstruction 0+00 2+75 As mentioned in the May Creek Drainage Improvement Baseline Stream Conditions Report (King County 20 !Ob), in-stream habitat in the surveyed reach of May Creek is greatly influenced by riparian plant communities. Aquatic habitat is much more complex in places where the riparian corridor has woody plants, such as willows, actively engaged with the stream channel and connected floodplain. Areas with no woody riparian plants are much more uniform and tend to have accumulations of fine sediments in the channel. This is most evident when comparing reaches with just reed canarygrass versus reaches with native riparian vegetation, such as willows. In areas where reed canarygrass Impact Analysis and Mitigation Plan 14 September 2011 May Creek Drainage Improvement Project I i • I I I I I I I I I I I I I I I I I I I I I I I I I I I dominates, such as Reach Four, the channel tends to be deeper and is 100 percent glide habitat. In Reaches One and Two, where some native willows grow along the stream banks and interact with the stream channel, some pools are also present. The proposed removal of willows (Table I) includes willows obstructing flow within the channel. This removal of willows actively engaged with the stream channel would reduce the number of pools within the surveyed reach of May Creek; it would also reduce or eliminate channel complexity within Reach Two. Six out of nine surveyed pools were formed by scour against willows. These six pools would be eliminated by the proposed project. Furthermore, dense willow branches crossing the stream in Reach Two function like a debris complex, creating numerous backwater areas during higher flows. As with pools, this habitat would be eliminated with willow removal. Willow removal would reduce pool formation and channel complexity. Eliminating these complexities would reduce available fish habitat. In addition to the removal of in-stream habitat components, willow removal would eliminate some streamside vegetation that shades the stream to maintain cool temperatures, and contributes organic debris and leaf litter, which support many stream food webs. This likewise would reduce fish (and other aquatic organism) habitat quality. Overhanging plants provide cover for fish rearing and seeking refuge along the streambanks. Over 80 percent of both streambanks have either reed canarygrass or willows, identified as obstructing flow hanging over the channel (2010b King County). Reed canarygrass, while undesirable from a native plant and diversity ecological perspective, does provide abundant cover for fish and it also shades the water to reduce water temperature. The entire project length would have its flow obstructing overhanging and in-stream vegetation removed. Fish and other aquatic organisms would lose the habitat provided by overhanging or in-stream vegetation until newly planted riparian areas can again begin to provide these needed functions after a few growing seasons. Typically these types of vegetation removal impacts would be considered temporary because the riparian area cleared would be replanted and would begin to provide the lost functions within a few growing seasons. However, in Table 2, these impacts were also considered permanent due to the lost functions that may not be restored within a few growing seasons. These permanent impacts include lost fish habitat from removal of reed canarygrass and willow. Willow branch complexes have taken 15 to 20 years to establish themselves in this manner and would not replicate pool-forming functions within a few growing seasons. Furthermore, the intent of the proposed riparian buffer plantings is to shade out reed canarygrass, thus the habitat function provided by reed canarygrass would be permanently lost and replaced by different types of vegetation (native plant species) that would likely provide different types of habitat. Impact Analysis and Mitigation Plan 15 September 2011 May Creek Drainage Improvement Project In addition, adjacent to Long Marsh Creek, sixteen trees over 6-inch dbh (primarily red alder) would be removed to reconstruct the channel for sediment management. This riparian buffer area would be replanted with native vegetation, but the temporal functional loss associated with removal of mature trees would take years to replace so this is being considered a permanent impact. 4.2. Wetland Impacts The proposed project would not permanently impact the wetland; however, there would be areas of temporary impacts within the wetland and wetland buffer. These consist of reed canarygrass and willow removal and construction of access roads. The primary wetland functions impacted include loss of grass and shrub habitat that may currently be used by birds, small mammals, amphibians, reptiles, and resident fish during certain times of the year. This project is not expected to change the amount of wet pasture or wetland in the project vicinity. Because of the high groundwater table in May Valley and no measureable difference in the geographical extent of overbank flooding (just the duration of flooding at the start and end of the rainy season) the wetland should not be affected. To confirm this, King County WLRD has installed five groundwater monitoring wells in various locations throughout the wetland to monitor pre-and post-project groundwater levels. Impact Analysis and Mitigation Plan 16 September 2011 May Creek Drainage Improvement Project I I I I I I I fl I I I I fl I I ___ 11!!11 ___ _ ---ia ----.. -- Table 2: Summary of Stream and Wetland Impacts Resource Resource Impact Area Type May Creek Type F 45,300 square feet** Channel May Creek Type F 14,500 square feet*** Vegetation May Creek Type F 14,500 square feet*** Vegetation May Creek Type F May Creek Floodplain May Creek Type F May Creek Sediment Transport Impact Analysis and Mitigation Plan May Creek Drainage Improvement Plan 17 Impact Type Functional Impact Permanent Impact Alteration of stream channel resulting in the loss of Excavation of sediment and reshaping in-stream habitat and complexity. of the Mav Creek channel. Permanent Impact Loss of in-stream habitat including fish rearing Removal of in-stream and overhanging habitat and six pools formed by willow branches. willow and reed canarvgrass Temporary Impact Loss of hiding cover, loss of thermal cover, loss of Removal of in-stream and overhanging bank stability, loss of surface water runoff filtration willow and reed canarvurass until buffer olantin11: is established. Permanent Impact The reduced connection of May Creek to its Reduced connection between May floodplain in May Valley will result in loss of off- Creek and the floodplain. channel rearing and refuge habitat for coho salmon and trout durin<> smaller flow events. Temporary Impact During construction and during the first storm event Increased sediment transport lifter the construction is complete, the following downstream to May Canyon and Lake mpacts may occur: Washington. I. Increased turbidity. 2. Spawning gravels or salmon redds covered with sand or silt (fines). 3. Increased deposition in the alluvial fan in Lake Washin"ton /fines). September 2011 Table 2 Continued Resource Resource Tvne Impact Area Impact Type Functional Impact May Creek Category 5,922 square feet Temporary Impact Disturbance to existing wildlife habitat (mostly reed Wetland #5 II Fill for construction access roads. canarygrass ), soil compaction. Buffer* Wetland 8,992 square feet Temporary Impact Disturbance to existing wildlife habitat (mostly reed Stream Fill for construction access roads. canarygrass and pasture grasses), soil compaction. May Creek/ TypeF 60 linear feet Temporary Impact Disturbance to existing in-stream habitat, including Long Marsh Excavation of gravels and change in an existing pool at the confluence. Creek channel geometry at the confluence. Confluence Long Marsh TypeF 16,520 square feet Temporary Impact Disturbance of existing stream habitat: Buffer Stream channel excavation, removal of I. Loss of shade 16 trees over 6" dbh (primarily red 2. Loss of habitat alders) as well as ground cover. 3. Creation of new off-channel habitat. * Wetland and stream buffers overlap throughout the project area so for simplicity wetland buffer and stream buffer impacts have been combined. ** This area calculation is based .on the width from top of bank to top of bank for the entire length of proposed sediment removal. *** The area was calculated by using 5,800 linear feet (2,900 linear feet on each bank) and assuming 2.5 feet of disturbance on each bank as part of the invasive vegetation removal. Willow removal is also included in this overall impact area. Impact Analysis and Mitigation Plan 18 September 2011 May Creek Drainage Improvement Project li\iiil lilii' liiiil1u1 i'iiiJ iiiiiil ---• • -~ iii) -6iiil~---1 I I I I I I I I I I I I I I I I I I I 5. Mitigation Approach 5.1. Impact Avoidance and Minimization King County has designed the project to avoid and minimize impacts to wetlands, streams, and buffers to the greatest extent possible. Total avoidance through design was not possible because the purpose of the project is to reduce the duration of flooding on local property owners by removing in-stream channel obstructions. To avoid and minimize impacts during construction, appropriate Best Management Practices (BMPs) would be used. Proposed construction limitations and BMPs include the following: I. Construction would comply with the King County (2009) Surface Water Design Manual for erosion and sediment-control features. Erosion-and sediment-control features include the use of ground covers such as plastic, fabrics (jute, excelsior, woven straw, or synthetic fiber), hydroseeding, sediment traps, silt fences, check dams, inlet protection and other proven techniques for minimizing erosion and sedimentation. The temporary sediment and erosion control (TESC) plan prepared for the project would include standard BMPs as well as site-specific measures to prevent and control erosion within the project area. 2. A Spill Prevention Control and Countermeasures (SPCC) Plan would be prepared prior to start of construction to address specific potential sources of spills, spill prevention and containment methods, spill response procedures and on-site materials and equipment, reporting, site security measures, and inspection procedures. 3. When practicable, all equipment fueling and maintenance would occur outside the wetland, stream, and buffer. All vehicles operated within sensitive areas would be inspected daily for fluid leaks before leaving the vehicle staging area. Any leaks detected would be repaired before the vehicle resumes operation. When not in use, vehicles would be stored in the vehicle staging areas outside the buffers. 4. The contractor would install temporary high-visibility fencing and silt fencing to demarcate and protect critical areas in the approved TESC plan. Any work that is required in critical areas would only be done at the engineer's direction and per the design plans. When the fencing is no longer needed, or at the engineer's direction, the contractor would completely remove and dispose of temporary high-visibility fencing and silt fencing. 5. Whenever possible, construction equipment would use existing farm access roads to cross the wetland and access the stream. 6. When wetland or stream access is needed outside of existing farm roads tracked or rubber tired machinery would be used to minimize ground disturbance and to Impact Analysis and Mitigation Plan May Creek Drainage Improvement Plan 19 September 2011 avoid the need to construct additional access roads. Direct access to the stream channel by equipment would only be allowed in specific areas where disturbance to vegetation can be minimized and removal of mature trees can be avoided. 7. In-water work would be done during low-flow stream conditions, in accordance with the regulatory in-stream work window. 8. During the sediment removal, the stream would be temporarily diverted around the work area as part of the temporary erosion-and sediment-control plan. This diversion may involve using one or more gas-powered pumps to remove water from the channel just upstream of the work area. The water would then be discharged downstream of the work area, in a safe, non-erosive manner. 9. May Creek would be protected during construction of the off-channel alcoves by leaving an earth plug between the existing stream channel and the excavation area for the alcove. Prior to removing the earth plug and connecting the alcove to the existing channel, a turbidity curtain would be installed to protect the stream from sediment and turbidity during the connection. A more detailed description of construction BMPs can be found in the project's Construction Water Quality Protection and Monitoring Plan (King County July 2011 ). 5.2. Compensatory Mitigation Impacts that cannot be avoided and minimized must be compensated for by constructing compensatory mitigation. The majority of the impacts to May Creek, Long Marsh Creek and the associated wetlands would occur in unincorporated King County, while the compensatory mitigation would be constructed in both King County and the City of Renton. 5.2.1. Mitigation Ratios The wetland impacts associated with this project are all temporary, and all the impacted wetland areas would be restored to equivalent or better function after construction. For this reason, mitigation ratios for wetlands were not applied to this project. King County and City of Renton mitigation requirements for streams are approximately equivalent (King County Code 21A.24.380 and City of Renton Municipal Code 4-3-050- Ll), with King County Code being slightly more stringent. For this reason, and because the majority of the stream impacts are located in King County, King County mitigation ratios are referenced in this report. The King County Critical Area Code specifies that any mitigation for impacts to streams must achieve equivalent or greater functions. Typically a 1: I mitigation ratio is applied for in-kind stream mitigation performed onsite; however, the project cannot offer onsite in-kind stream mitigation because adding Impact Analysis and Mitigation Plan 20 September 2011 May Creek Drainage Improvement Project i 11 I I I I I I I I ll I I I I I [I I I I I I I I I I I I I I I I I I I I mitigation in the May Creek channel conflicts with project goal of flood reduction. For this reason, onsite out-of-kind mitigation in the form of riparian buffer and wetland enhancement is being proposed to compensate for in-stream impacts. King County and City of Renton code does not provide specific mitigation ratios for out-of-kind mitigation, but because out-of-kind mitigation replaces different functions from those that are impacted, the replacement ratios typically must be higher in order for mitigation to achieve equivalent or greater functions. For this project, the proposed replacement ratio is approximately three acres of wetland enhancement for one acre of in-stream impact to the May Creek channel (3:1 ratio). The proposed replacement ratio for impacts to in-stream and riparian vegetation is approximately two acres of riparian buffer planting for 1/3 acre impact to May Creek vegetation (6:1 ratio). The proposed replacement ratio for impacts to trees along Long Marsh Creek is approximately 2 trees replanted for each tree removed (2: 1 ). 5.2.2. Mitigation Functions The proposed compensatory mitigation (Table 3) is focused on enhancing wetland and riparian habitat functions in May Valley. The wetland enhancement includes off-channel alcoves that would increase fish habitat complexity in the wetland during high flows and would partially replace some in-stream habitat functions lost due to the in-stream sediment and vegetation removal. The wetland enhancement also includes suppression of reed canarygrass and replanting of native vegetation, which would improve general wildlife habitat complexity in May Valley. The riparian buffer planting would improve buffer function in the long-term by minimizing reed canarygrass infestation and providing native vegetation that would shade the stream, provide bank stability, capture sediment from pasture runoff, and provide wildlife habitat. The riparian buffer plantings would be installed in many areas where only reed canarygrass or pasture grass currently exists. While the proposed mitigation does not provide the same functions as those being impacted (impacted functions are primarily in-stream habitat while mitigation is focused on wetland/riparian habitat function), it does provide an improvement over existing conditions over a large area (approximately 5 acres total). A more detailed discussion of the functions provided by the mitigation is provided in Section 5.5. The mitigation proposed for this project is summarized in Table 3. Impact Analysis and Mitigation Plan 21 September 2011 May Creek Drainage Improvement Project liiil Table 3: Mitigation Ratios and Proposed Mitigation Areas Impacted Impact Resource Area May Creek 45,300 square feet Channel May Creek 14,500 square feet Vegetation May Creek May Creek Floodplain May Creek Sediment May Creek Transport May Creek 5,922 square feet Wetland #5 Impact Analysis and Mitigation Plan May Creek Drainage Improvement Plan ---liiiiJ - Impact Type Permanent Excavation of sediment and reshaping of the May Creek channel. Permanent and Temporary Removal of in-stream and overhanging willow and reed canary grass. Permanent Reduced connection between May Creek and the floodplain Temporary Increased sediment transport downstream to May Canyon and Lake Washington. Temporary Fill for construction access roads. 22 --~ - Proposed Mitigation 3 acres of out-of-kind wetland enhancement west of 148th A venue SE including off-channel alcoves, reed canarygrass suppression, replanting with native vegetation, and L WD placement. 2 acres of riparian/wetland buffer planting for 15 feet on both sides of May Creek, protected by fencing (to restrict livestock access) and permanent conservation easements. Compensation is included in the 3.0 acres of proposed wetland enhancement west of 148th Avenue SE by constructing off-channel alcoves to provide fish habitat during higher flows. Off-channel alcoves in the wetland enhancement area would provide sediment storage for the temporary pulse. Construction access areas would be restored to previous condition using native plants or appropriate seed mixes. September 2011 EB Ml =. -~ -5-1 Proposed Replacement Ratio 3:1 6: 1 Included in the 3: I ratio above. Included in the 3: 1 ratio above. Area would be restored. -~ liiijJ -!!!11!!!!1 -------------------Table 3 Continued Impacted Impact Impact Proposed Proposed Resource Area Type Mitigation Replacement Ratio Temporary Construction access areas would be restored to Area would be Buffer* 8,992 square feet previous condition using native plants or appropriate Fill for construction access roads. restored. seed mixes. May Creek/ Temporary Channel and confluence would be reconstructed and Long Marsh 16,520 square feet Excavation of gravels in May restored to include a wider channel with streambed Area would be Creek and change in channel restored. Confluence geometry at confluence. gravels, and LWD. Permanent 16,520 square feet Stream channel excavation, Area would be Long Marsh Buffer replanting with 32 trees, 150 willow stakes, and restored. ( 16 trees greater than removal of 16 trees over 6" dbh Buffer 6-inch dbh removed). (primarily red alders) and 156 shrubs, and 282 emergents I groundcover. Trees Replaced groundcover. at a 2: I Ratio *Wetland and stream buffers overlap throughout the project area so for simplicity wetland buffer and stream buffer impacts have been combined. Impact Analysis and Mitigation Plan 23 September 2011 May Creek Drainage Improvement Project 5.3. Compensatory Mitigation Goals The mitigation goal for this project is to achieve no overall net loss in habitat functions in the May Creek subbasin. 5.4. Compensatory Mitigation Objectives The objectives listed in this section were selected after analyzing multiple potential mitigation alternatives. Some of the mitigation alternatives considered but not selected included: o In-stream L WD: Enhancement to in-stream habitat by placing L WO in the stream channel was considered, but this option was eliminated because placing L WD in the channel is counterproductive to the primary project goal of removing flow obstructions. As a compromise, L WD would be placed in off-channel alcoves adjacent to the stream where it would not obstruct flow, but would provide habitat during higher flows (see Objective I below) and would also be placed throughout the wetland enhancement area. o Side Channels/Floodplain Terraces: Creation of side channels and/or floodplain terraces in the open space area west of 148th A venue SE was considered, but this option was eliminated due to the lack of elevation change and potential for sediment accumulation on this property. The lack of elevation change and sediment accumulation posed a potential risk of fish stranding in side channels and terraces during the summer low-flow. The final mitigation objectives for the project include: I. Objective 1 -Wetland Habitat: Enhance approximately three acres of riverine wetland on the west side of 148th Avenue SE to increase fish habitat complexity during high flows and general wildlife habitat complexity year-round. Enhancement would include: a. Construction of approximately 0.24 acres of off-channel alcoves along May Creek with emergent wetland vegetation, LWD (16 pieces), two snags, and streambed gravels. b. Suppression of approximately three acres of reed canary grass using weed fabric, planting of native wetland vegetation, and placement ofLWD (60 pieces). 2. Objective 2 -Riparian Habitat: Enhance approximately two acres of riverine wetland/riparian buffer by suppressing invasive species and planting a 15-foot wide fenced buffer of native vegetation along both banks of May Creek Impact Analysis and Mitigation Plan May Creek Drainage Improvement Plan 24 September 2011 I I I I I I I I I I I I I I ·I I I I I I I I I I I I I I I I I I throughout the project limits (approximately 2,900 linear feet) east and west of 148th Avenue SE. 5.5. Compensatory Mitigation Description/ Design Compensatory mitigation for temporary wetland impacts and permanent stream impacts along May Creek would focus on restoring wetland and riparian habitat in May Valley. Please note that in the majority of the project area, the stream buffer for May Creek is contained within the delineated wetland boundary. For this reason the riparian enhancement could also be considered wetland enhancement, but they are discussed separately below. 5.5.1. Riparian Enhancement Area The riparian enhancement area encompasses a 15-foot wide planting area along each side of May Creek for the entire project length (approximately 2,900 linear feet) for a total of approximately two acres. In planting areas where reed canarygrass is the dominant vegetation, the grass would first be mowed if necessary, and covered with a weed barrier fabric intended to shade out the grass in the short-term. The new plants (primarily trees and willow stakes) (Appendix A· Sheet 18) would be planted through the temporary weed barrier fabric. This would improve long-term function of the riparian area as a whole by establishing populations of tree and shrub species that would, in time, serve as perches, nesting habitat, snags and provide a native seed bank. Establishing vegetation would also create a dynamic stability to the stream bank and would help filter out sediment that is suspended in runoff from the adjacent farms and pastures. 5.5.2. Wetland Enhancement Area The wetland enhancement area is located on the west side of 148th Avenue SE (Appendix A-Sheet 14) in a designated open-space tract in the City of Renton owned by the Stonegate Homeowners Association. In addition to the riparian buffer planting described in the previous section, approximately three more acres of enhancements would be constructed on the west side of 148th Avenue SE and include: I. In-stream Enhancements: Approximately 0.24 acre of off-channel alcoves would be constructed along May Creek in the wetland on the west side of 148th Avenue SE. The existing banks would be replaced with a terrace (wide bench) and gradual slopes. Within this terrace, an alcove would be created that incorporates woody debris (Appendix A -Sheet 14) and streambed gravels would be placed for the first 15 feet adjacent to May Creek. Jute matting would be placed in the alcoves beyond 15 feet to minimize erosion, and the alcoves would be densely planted with emergent and scrub-shrub wetland plants. This would increase the amount of available instream habitat and would decrease flow velocities, thus improving the Impact Analysis and Mitigation Plan 25 September 2011 May Creek Drainage [mprovement Project quality of off-channel overwintering habitat. During a flood, water would inundate the terrace and interact with the woody debris and vegetation. Sediment deposition would occur outside of the main channel in the alcoves. The woody debris and vegetation would trap and hold sediment and then allow a more gradual pulsing of sediment back into the channel over time. This mitigation would improve winter rearing habitat for salmonid and other fish species in areas adjacent to the mainstem of May Creek. The mitigation would increase biological functions for riparian species within May Creek through introduction of woody debris; woody debris would also provide substrate for invertebrates, hiding habitat for juvenile fish, perching habitat for riparian birds, and desirable niches for river otters, other mammals, and crustaceans. The proposed mitigation is also designed to enhance refuge and rearing habitat through the establishment of habitat features along May Creek. Such enhancements would make these habitat features available to salmonids and other wildlife species at a wider range of flow rates on May Creek. In addition, willows and other native shrubs would be planted along streambanks and confluence margins to increase cover of overhanging branches above the waterways. Lastly, the removal of reed canarygrass and root system from the floodplain would create additional area for sediment deposition, thereby allowing some decrease in fines downstream. 2. Wetland Habitat Enhancements: In addition, to the 0.24 acres of off-channel alcoves, approximately 2.75 acres of wetland habitat enhancement would occur on the west side of 148th A venue SE. In this area, reed canarygrass would be suppressed using a weed barrier fabric and native vegetation ( cottonwood, willow, and dogwood) would be planted through the fabric. L WD (76 pieces) would also be placed throughout the wetland. These activities would improve the wildlife habitat complexity in the wetland, providing habitat for mammals and riparian birds. It would also increase the native seed bank in May Valley and provide a future source for L WD. Impact Analysis and Mitigation Plan 26 September 2011 May Creek Drainage Improvement Project i I I I: I I I I I I I I I I I I I I I I I I I I I I I 6. Performance Standards, Monitoring, Maintenance, and Contingencies King County WLRD would provide monitoring services during and after construction of the proposed project. 6.1. Performance Standards I. Regulated Noxious Weeds: If noxious weeds are discovered during monitoring, they would be treated according to currently established standards. 2. Invasive Weeds: The percentage of buffer and wetland planting areas covered by non-regulated invasive weeds would not exceed ten percent through the monitoring period, except for reed canarygrass. Due to the existing JOO-percent coverage ofreed canarygrass in the project area, it would not be possible to achieve less than ten percent coverage of this species during the monitoring period. Over the long-term, reed canarygrass would be reduced in density by meeting the Vegetation Coverage performance standard below. 3. Vegetation Coverage: Within the wetland and buffer planting areas, woody native vegetative cover shall be 80% by the end of the monitoring period. 4. Vegetation Survival: Within the wetland and buffer planting areas, inspections for plant mortality would be conducted annually by an ecologist during the monitoring period. During monitoring years one and two, 100 percent of dead plants would be replaced. During subsequent monitoring years, dead plants would be replaced as needed to ensure that coverage performance standards are met. 6.2. Monitoring Construction Monitoring Construction-phase monitoring would focus on protection of water quality and important vegetation that is to be preserved. King County WLRD prepared a Construction Water Quality Protection and Monitoring Plan (King County July 2011) which describes the construction monitoring techniques and best management practices that would be utilized to monitor and protect water quality. Post-construction Monitoring During the first year after construction an As-Built report will be prepared and submitted to the agencies. Vegetation would be monitored throughout the ten-year monitoring period. Post- construction monitoring would be conducted to establish whether performance standards Impact Analysis and Mitigation Plan 27 September 20 I l May Creek Drainage Improvement Project for the mitigation have been met. Monitoring reports would be submitted at the end of years one, two, three, five, seven, and ten. These reports would describe and, to the extent possible, quantify the level of success of the mitigation. Data collected on physical and biological parameters would be compared to the established performance standards defined in Section 6.1. 6.3. Maintenance All planted areas would be watered through the first year of installation as needed. Other maintenance activities would be performed for ten years as needed, including weeding, watering and fabric maintenance. After vegetation has matured enough to reduce the reed canarygrass density (about two to three growing seasons) the weed fabric would be removed by hand. 6.4. Protection The mitigation areas would be fully fenced to restrict livestock access and would be demarcated with wetland protection signage. King County would also protect the mitigation areas in perpetuity by recording a conservation easement, or similar document, on the title of each property. 6.5. Contingencies Based on the data collected during annual monitoring of the completed mitigation site, it may be necessary to implement contingency measures to ensure that the established mitigation performance standards are met. These include mitigation objectives for plant survival, vegetation cover, and amount of invasive species, all of which help to define viable riparian functions. Several factors, both artificial and natural, could have detrimental effects on the success of the mitigation sites. These factors include changes in hydrology from drought or flooding, water pollution from excessive nutrients or toxicants, erosion of soil during flood events, plant mortality, and competition from invasive plants. King County would commit to the maintenance, monitoring, reporting, and the replacement of dead plants as required to meet the established performance standards for plant cover and survival and for measures to control invasive species. Impact Analysis and Mitigation Plan 28 September 2011 May Creek Drainage Improvement Project I I· I Ii II I I I I I I I I I I I I I I I I I I I I I 7. References Anchor QEA, LLC. 2110. May Creek Erosion Stabilization Draft Report May Creek Sediment Transport Study Phase 3. Prepared for King County Department of Natural Resources. Bicknell, Brian, et al., July 2005. HSPF Version 12.2 User's Manual. Prepared for U.S. EPA-NERL. Prepared by Aqua Terra Consultants. King County. 2011. Construction Water Quality Protection and Monitoring Plan. July 2011. Prepared by King County Department of Natural Resources and Parks. Seattle, Washington. King County. 2010a. May Creek Channel Restoration Project Wetland Delineation Report. March I 0, 20 I 0. Prepared by King County Road Services Division Environmental Unit for King County Department of Parks and Natural Resources. Seattle, Washington. King County. 20 I Ob. Baseline Stream Conditions May Creek Drainage Improvements CIP# 9Al205 Revised December 2, 2010. Prepared by King County Road Services Division Environmental Unit for King County Department of Parks and Natural Resources. Seattle, Washington. King County. 200 I. Final Adopted May Creek Basin Action Plan. King County. 1995. May Creek Current and Future Conditions Report. August 1995. Prepared by Foster Wheeler Environmental Corp, King County Surface Water Management Division, and City of Renton Surface Water Utility. USACE, March 2008. HEC-RAS, River Analysis System-Hydraulic Reference Manual (Version 4.0). Washington Dept. of Fisheries (WDF). 1975. A Catalog of Washington Streams and Salmon Utilization, Volume I Puget Sound. Washington Department of Ecology (Ecology). 2004. Washington State Rating System for Western Washington. Publication No. 04-06-025. Olympia, Washington. Impact Analysis and Mitigation Plan 29 September 2011 May Creek Drainage Improvement Project Appendix A -May Creek ][))rainage Improvement Design Plans Impact Analysis and Mitigation Plan 30 September 20 I I May Creek Drainage Improvement Project - .. "" m 1:,,1 ,~ -;!i i8.'1 I:._,. ·7':l ' 1 flnD 8001(: """""' ~ 09056 01-20101 KINC COUNTY 01-2010 SURV[Y BAS[ ~NC COUNTY 02-2010 TREVOR CRAY, PLS 02-2010 CHECl<E!>: DALE ~ 02-2010 NUM. \ VIONITY MAP COALFIELD .PROJECT 0 LOCATION --...:::: .. I I In r--t----- ,, . '<t 0 INDEX SHEET DESCRIPTION 1. VICINITY MAP AND INDEX 2. LEGENDS AND ABBREVIATIONS J. SUMMARY AND QUANTITIES (draft version) 4. EXISTING CONDITIONS, SHEET KEY, LEGEND, CONSTRUCTION NOTES 5. TEMPORARY EROSION AND SEDIMENT CONTROL PLAN AND LEGEND 6. TEMPORARY EROSION AND SEDIMENT CONTROL PLAN 7. TESC SEDIMENT DISPOSAL AND PUMPING LOCATIONS (draft version) 6. TEMPORARY EROSION AND SEDIMENT CONTROL NOTES AND DETAILS 9. TEMPORARY EROSION AND SEDIMENT DETAILS 10. PLAN AND PROFILE STA. 0+00 TO STA 8+00 11. PLAN AND PROFILE, STA. 6+00 TO STA. 16+20 12. PLAN AND PROFILE, STA. 16+20 TO STA. 24+00 1 J. PLAN AND PROFILE, STA. 24+00 TO STA 29+00 END OF PROJECT 14. WETLAND AND RIPARIAN MITIGATION PLAN 15. CROSS SECTIONS AND HABITAT MITIGATION DETAILS 16. CROSS SECTIONS AND HABITAT MITIGATION DETAILS 17. FISH HABITAT ENHANCEMENT INSTALLATION DETAILS AND NOTES 1 B. PLANTING TABLES 19. PLANTING PLAN APPR<MD: DON ALTHAUSER. P.[. 912011 '"""'"' DOUG CHIN 9 12011 "''"""' "'"""'' DAlE NELSON 9 12011 -\\ I I I ~ OESlf.N ENlERED: M. RADEUA 9 12011 IB'1'1DA.tt 1 • KCFCZO No. PROJECT No. SURVEY No. MAINTENANCE OMSION No. 9A1205 4 ~ . . , Kirrngi <Coll.ll~Y Department of Natural Resources and Parks Water and Land Resources Division Stonnwater Services Section Capital Services UnH Christie True, Director Department or Natural Resources end Perks ~J l ~ MAY CREEK DRA~NAGE ~MPROVEMENT SE M~y v~~!ey !Rd.+ 143th Ave SE ~ King County Department at NidlnJ R8IICU'Cell and Plllb Water and Land Rasoun:es DMslon -----""" """"' -- MAY CREB< DRAINAG'E IMPROVEMENT 'llal!1TY MAP /II(!) OOlEX SHEET 1 OF 19 SHEETS 2006-16 'f;II IJ,'!il ffl ~ iC.3' ,t:~ f.·"I -~ ··~ :;,,,;,i SYMEIQL DESCBIEI!Ql!I EXISTING SYMflQL QESCBIEI!Ql!I 0 MONUMENT IN CASE (MIC) • HUB AND TACK ---------EXISTING DRIVEWAY, EDGE Of ASPHALT --PROPERTY LINE ol!: REBAR AND CN' KING COUNTY • BERNTSEN NAIL HW--O.H.W.M. UNE --,;--~--,.-~x--x-FENCE-WIRE. BARSED WIRE. SPLIT RAIL • F'DRIIER FENCE POSIS, GATE POSr.i GUARDRAIL -EXISTING LOGS -• , -• • -• , -· • -• • -TOE Of CHANNEL -MAY, LCNG 6 UTIUTY POLE WITH OR WITHOUT I-· · -· · -• · -'· -' · -MARSH; AND INDIAN MEADOW CREEKS UNDEROROUND CONNECTIONS T GUY WIRE ROCK RETAINING W&L AT TSEGAY ENTRANCI ~ ~-==--== a SIGN ~ TElD'l«lNE RISER -"'--"'--"'--EXISTING WETIAND BOUNDARY X WATER VALVE 41) LARGE ROCK/BOULDER 4q~•~uQ-•~guaa~~a• EXISTING WETIAND BUFFER 0 = oa=,o ··= = EXISTING SIREAM BUFFER TREE DECIDUOUS ------100 YR. FLOODPLAIN UNE r) SNAG (DEAD TliEE) ;;,::, ,,· TREE BUSH/SHRUB ~vi _.,c:; L~ lREE EVERGREEN C //'\ TEMPOBABY EROSIO~ SEDIME~IAIION .m!lllll. IJFSCRleil!Jti CONIBOI, .sxr.mm. orscRleDOtl ~ CONSTRUC110N ACCESS ROAD \' ........ m . · .. ·.····.·· STAGING AREA SPOILS AREA ••••••• • • + • + + ·.·. ·.·.·· .. •••••••••• C&G ctEARING AND GRADING UM1TS WEIGHTED SILT CURTAIN H H M IE It SILT FENCE . APPROVED: DON Al.llWJSER. P.E. 9/2011 FIEUJ """"' 09056 01-2010 KCfCZO No. 01 2010 • • ~ DOUG CHIN 9/2011 SURYMI> KING COUNTY -~ ; • PROJECT No. S\IIMY BASE ~NQ COUNTY 02 2010 OE5IOHED:: DALE NEl.SON 9/2011 SURVEY No. TREVOR CAAY. P1.S 02 2010 .. CH!DCEI> ..... ,-~-02-2010 -· 9/2011 MAINTENANCE ' DESGN DOER£D; M. RADEL.LA OMSION No. NUii. """""' "' .... llESliitl I EGE!lll ~/ll/h'·/A SEDIMENT REMOVAL AR£A AQilltttdrldtri IN-STREAM WIU.OW PRUNING AREA --·---·-PLANTING MmGATION LINE J15' BUFJ'IR) and PROPOSED CONSERV!i ON E'ASEMENT --x ---X --· CONSERVATION EASEMENT/PLANTING MmGATION FENCING ....... W.S.LOJt.Z. NAO 83/91 ABBREVIATIONS ABBREVIATION DEFINITION SEC SECTION .TWN TOWNSHIP NAW 88 R. E RANGE EAST W.M. WILLAMETTE MERIDIAN STA. STATION R-0-W RIGHT Of WAY NOTES: 1. PARCEL LINES SHOWN ARE KING COUNTY GIS PARCEL LINES AND ARE SHOWN FOR VISUAL PURPOSES ONLY. THESE PARCEL LINES ARE NOT ACCURATE ENOUGH TO BE USED FOR PURPOSES Of SURVEYING, DEED TliKES, OR 1iNY OTHER LANO TRANSACTIONS OR DELINEATIONS. 2. IIASlS Of BEARING FOR THIS PROJECT IS N2"01'12"E. THE INVERSE BETWEEN KING COUNTY CONTROL POINTS 3871 (N188995.987, E1318885.925) ANO 3705 (N191108.582, E13167B0.44,MINAD 63/91 COORDINATE VALUESl' 3. BENCH MARK IS KING COUNTY CO OL POINT NUMBER 3871, WITH NAVD68 ELEVATION Of 405.42, ~ King County SHEET MAY CA.EK OAAWAQf: IMPROVEMENT 2 9A1205 DepartmantofNalural ~ and P8lb OF water and Land Resources Division ---'19 --Unll L.BISl(l)8 AKI) AB!l'J:ViA'l10l'!II SHEETS Chddtl Tn,e, ~ • 2006-16 =· -~ m a - "' ~ !l~ :,,,-1; hi ~'~ PROJECT LIMITS: • ITEM I TOTAL NO. QUANTnY STD. UNIT I ITEM NO. LENGTH: x PROJECT NUMBERS ITEM X SUMMARY OF OUANT~T~ES AS-BUILT ITEM I TOTAL NO. QUANTllY ~ STD. UNIT I ITEM NO. ~ PROJECT NUMBERS AS-BUILT ITEM <d~ ./"' > " ?~ 7 --5.-;; -· ... -··· ---1-1 I I= 1 11 ~ ~ ~ 7 '~li:i~ i,,-1 I ·~ - I I I I . I .. 2 ~n;al~ 17 ' ' ...-" I \ \ ' ' I ' ~ I 1-,~1-r~ __ J~!?\ ~ ~ ~ ' ' 1 1 . 1 u lz _ -==1=====-=-----=l===l==1===1=== .-I U§IS == .caa,r_COIIClll!l1!~~VB1911' I I l~~I · '-' ' if~ SPEfl#:1 PRQ\DSIONS F1EID IIOOIO 09056 01-2010 ..... ~ APPfKMD; DON ALTHAUS-P,E. 9 12011 ~ King County S>JR'IEYEI>. KtNG COUHTY 01-2010 ~ ~ -KCFCZD No. • ~ • -DOUC CHIN 912011 SIJR'IEY BASE ..,lfil"l CCUNTY 02-2010 PROJECT No. 9A1205 DeparlmantofNd.md Retcunm ft Parb TREVOR CRAY, PlS 02-2010 a.LE NELSON 912011 Water and Land Resourt::es Division -SURVEY No. --- a,,acm, -··~ -~--...... _.,g . ' ~-.. Ce,ttal Bomceo Unit DESGN EMTDE>: M. RADWA 9 1 2011 MAIKTENANCE • CMdt T,w,, Dt8c:mt" -Rl'IISION BY DATE DMSION No. SH!p" 3 OF s SHEETS MAY CR K DAAINA~ IMPROVB\llENT ~ OP CUANllllEIB 2008-18 ·~ •. , "' n F'l n11 '' ,a ;;'"Jl \ (> /r I C:::::::::.: I ,.:1. -"'~ -GA.Th -------------------SEC. 2, lWN.23, R. 5 E, W.M. ·---'""'---- 11 j I I l"I t'!!:\l!f'JI I I 11D O 11D 2DD ;m ~IN FEET DESIGN I fCEND EXISJINC LECENP f?#l#/@ffA\ SEDIMENT REMOVAL AREA IIZlm IN-STREAM WIUDW PRUNING AREA -• • -• • -• • -11)E (BOTTDM) OF STRfAM -------Dlflif!#AY UNE WEil.AND BUFFER (110') PER KING COUNTY CAO REGULATION (FOR PURPOSES OF 1HIS PROJECT ONLY) --- F£NCE • SUR'IEY COfflROL --PROPERIY UNES HAROlD GAMBINI, JR 15019 S.E. MAY VALLEY RO SIREAM BUFFER (165') -o-w UHES PER KING COUNTY CNJ REGULATION _\V IV--D<UNWB> wtn.AND -1 HOLD -PRECONSTRUCTION MEETING. \ \ ¢,0',/!> :ii;, ESTABLISH REQUIRED SIGNAGE ANO TRAFFlC PLAN REQUIREMENTS AS APPROVED BY KING COUNTY ENGINEER. STAKE OR FLAG 1HE LIMITS OF CONSTRUCTION. SEE NOTES 1J, 16, AND 17 FOR _ CONSTRUCTION LIMITS. ~ , lDCAlE AND MARK UTIUTIES CO ' INSTALL lEMPORARY EROSION CONTROL MEASURES SHOWN ON SHEETS 5 TO 9. ~ • INSTALL CONSTRUCTlON ACCESS RAMP ANO CONSTRUCTION ENTRANCE PAD AS NEEDED .__e~NOER s+ RASPHAL BUnAR AND APPROVED IN 1HE FIELD BY ENGINEER. \ ~ '9848 148™ AIIE SE INSTALL STAGING AND TURN AROUND /IRFAS AS APPROVED IN 1HE FIELD BY 1HE \ Pi / 'vl@p ENGINEER. !fl! r-, <§1> (FOR PURPOSES OF 1HIS PROJECT ONLY) PlANTING MmGATION LINE {15' BUFFER) AND PROPOSED CONSERVATION EASEMENT BOUNDARY WHITNEY & .uFR£Y WALK£R 15125 S.E. MAY VIJJ.I.Y RO @) I 1/~---1 ~i \"- ' I MARY LOUISE CEUGOY~a M NORTON · 15329 S.E. MAY RO ' ,· ~ "- ~"- TO MINIMIZE DISTURBANCE TO EXISTING NATIVE VEGETATION, MACHINERY ACCESS ALONG \ j,, -~'-,'- 1HE STREAM WILL ONLY BE ALLOWED APPROXIMAlELY EVERY 50 FEET AS SHOWN ON • ~ SHEETS 5 AND 11. \ • , REMOVE A.OW OBSTRUCTING WILLOWS AS DESCRIBED IN NOlES 1J TO 15. '-.._ 0. REMOVE SEDIMENT AND REED CANARY GRASS AS DESCRIBED IN NOlES 16 TO 21, I ~---::-=__ - 1, REMOVE ANY lEMPORARY CONSTRUCTION ENTRANCES AND ACCESS ROADS 1HAT ARE NOT _ ' ' -· = = --· ------=== NEEDED FOR MmGATION CONSTRUCTION > ~ 2, CONSTRUCT MmGATION AND REVEGETAlE AS SHOWN ON SHEETS 14 TO 18. ' r fl_""'~ y "-KIDANE (10008 I 'f'E-S; • J. WILLOW REMOVAL WILL OCCUR IN SELECTED LOCATIONS FROM STA o+oo TO STA 5+40: LJ ) //~ SEE TABLE ON SHEET 10 AND DETAIL SHEET 15. ------ 4. WIUDW BRANCHES AND ROOTS 1HAT ARE LIMmNG 1HE S1REAM FLOW WILL BE REMOVED \ ~-"- BY HAND AND/OR HANDHELD SMALL MACHINERY TO MINIMIZE DISTURBANCE. WILLOW I BRANCHES 1HAT ARE NOT LIMmNG STREAM FLOW WILL NOT BE REMOVED. EXACT WIUDWS TO BE REMOVED WILL BE DIRECTED IN THE FIELD BY 1HE ENGINEER OR ECOLOGIST. 5. WOODY NATIVE VEGETATION THAT IS REMOVED WILL BE MULCHED ANO SPREAG OVER REED CANARY GRASS TO SHADE OUT GRASS AS DIRECTED IN 1HE FIELD BY 1HE ENGINEER OR ECOLDGIST. 6. SEDIMENT REMOVAL IN 1HE CHANNEL WILL OCCUR FROM STA 5+40 TO STA 26+26 7. REED CANARY GRASS REMOVAL IN THE CHANNEL WILL OCCUR IN SELECT LOCATIONS FROM STA o+oo TO STA 29+00. SEE TABLE ON SHEET 10. 8. MACHINERY FOR REMOVING SEDIMENT ANO REED CANARY GRASS SHALL BE OPERAlEO FROM 1HE BANK. 9. SEDIMENT ANO REED CANARY GRASS REMOVAL SHALL BE DONE IN 1HE DRY. A STREAM BYPASS PLAN SHALL BE SUBMITTED TO 1HE ENGINEER IN ADVANCE OF INSTALLATION FOR FINAL APPROVAL. PRIOR TO INSTAUATION OF THE BYPASS THE KING COUNTY ECOLOGIST WILL REMOVE FISH FROM 1HE CHANNEL. 00 NOT INSTALL THE BYPASS UNTIL YOU HAVE BEEN GIVEN PERMISSION BY 1HE KING COUNTY INSPECTOR TO 00 SO. :o. ElCCAVAlE SEDIMENT AND/OR REED CANARY GRASS FROM NOW ORY CHANNEL.. 1. RETURN Fl.OW TO CHANNEL UNDER DIRECTION OF ENGINEER/ECOLOGIST. SEE NOlES ON SHEET 8. D90S8 01-201 _ .. -·" APPRCMD: DON ALlHAIJ FIE1D B0010 ' . """""" KING COUNTY 01-2010 • PROoEC1' • .. • .. -DOUG CHIN SUIMY am; ~NG COUNTY 02-2010 TREVOR CRAY, PLS 02 2010 ......... DAU: NELSON "'"""" ... -·-.... ---_ .. ., _, DESICN OfflRED: M. RADEUA ........ -"' DA]< I•\ ls~ ( ( 1.~ \~ I 1 LI P.E. 9 2011 9 2011 9 2011 9 2011 t<CFCZO No. PROJECT No. SURVEY No. "-\ I NOTES: 1. PARCEL LINES SHOWN ARE KING COUNTY GIS PARCEL LINES AND ARE SHOWN FOR VISUAL PURPOSES ONLY. 1HESE PARCEL LINES ARE NOT ACCURAlE ENOUGH TO BE USED FOR PURPOSES OF SURVEYING, DEED TAKES, OR ANY 01HER LAND TRANSACTIONS OR DELINEATIONS. 2, BASIS OF BEARING FOR 1HIS PROJECT IS N2'01'12'E. 1HE INVERSE BETWEEN KING COUNTY CONTROL POIKT'S JB71 (N1BB995.9B7, E1J16B85.925) AND J705 (N19110B.SB2. E1J1B760.4"'1)(NAO BJ/91 COORDINAlE VALUES). ). BENCH MARK IS KING COUKTY CON!Rol POINT NUMBER JB11, W11H A NAVDBB ELEVATION OF 405.42. ~ King County 9A1205 Department ol Hahnd R8llouroeo and Patb Walat and Land ResoLlft81 Division ------MAINlENANCE 4 Cllrlde T,ue, 0/l-=r DMSION No. ll/lAY CHES<. OAAINAQE lMPROVW ElCISIOOll ~ St!EET KEY, LBISIID, ~ r,ecm;s ....... W.5.Lll.N.Z. NAD 83/91 """" .. SHEET 4 OF s SHEETS 2006-16. -· ""'i 111 I [¥111 I . .o --~ ~ 120 SCALE IN Fm TESC L£GEND ... + + + + + + + + + .__. ©<><xx:& / .,....., AREA -- ~ JO:tsS Rew> ~1111,l :i:i:i:,:,;,;1 I i I I CONSl1WCl10N """"'" g + ... -· -·--·-we;1~ ............ . el = = '2? STR£AII ACCESS. APPROXlMATE..Y EVERr t50 Fm' CONCR£l'E BMRl£RS wmt Pt.ASTie UHER SANDMO MRRIER OR EQUIYAL.£HT --' --' -PI.ANTING/Ml11G4l10N BWPASS HOSE AND PUMP BUFFER JI. It It a JI SILT FtHCE c::::::i ' I = I ' l c:::= SIRFAM BUFFER WEIGHTED SILT f!NCE/alRTAIN c:i a c CJ e1 m CJ CJ ci a er WETUND BUFFER ---C&C---ClEARIHG AND GRADIHC LIMITS --100 'l'R ru>ooPLAIN .,,.--___ :-- 8.e.1W1y VAU.ey RoJU> '- ,, \\ ! \,· ,1 I ~·-·~·---. ' :t;/~l ~-"-~·:~ ' ,so\'.'"so; .:a::~~c~ ~ 0 ~~. ,-~, '"srnEAM BUFFER~ ,\ DUNVEGAN \\ TRU T ~ ~ '\ 0 0 .j' ;!: N 'f. :: ...... -~ . '=--Ci,ta;:; -' -'d:,tU . 'i\ ~ \, '" TEMPORARY EESS LANE 15' WID!:, \' · SP~ APPRO SQ'...APAIU (lYPICALJ." ~ ( EXISTING VEGEl'A 0N BEIWEEN !ANES \I NOTr: ~ ~ WIIJ..,ij9T BE OISIURBm ~ LANE,.I \ • · \ WILL Q(T[N01'FIIOM ~.JP EOOE"'<fF .. t\ WILLOWS:-ACCESS POl!jTS"w1LL BE • . .,. DIR IN FIEtD" SY . 7 . -~Cot.OGIST TO AVOID REMOVE CONSIRUCTION ENTRANCE /'110 ACCESS PAD UPON COMPLD10N OF CONSTRUCTION. PINIT AU. AA£>S WITH NATIVE VEGETATION PER ECOLOGIST. \ ;a,-~/ ~~ EQ3fpJO MAJ:ii~ OFF \ ~<'l 7 -MINIMIZE-AeT-TO INCLUDE ~ 'TRACK CAVATOR, OR EQilJVAI.EtlT, . ..., .. W.S.L.C.N.Z. NAO 83/11 .. ,,, .. A!1D KEO DUMP UCK OR • .,,.,,... EQUIVALENT. -EXls,TING FAAM FENCES TO BE TEMllORARILY RELOCATED ANO RESTORED \ \ \ \ CALL 2 WOffl<INQ DAYS \ BEFOllE YOU DIG 1-800-424-5556 \ (UNDERGROUND UTILITY LOCATIONS AR£ N'PflOX.) .,.- AFTER CONSIRUCTION SILT FENCE [D • - CONSTRUCTION CE. AVOID EXISTINO UTILITIES ffi - -. -~ I I \-.. ~ --STREAM BYPASS SUMP, PUMP, HOSES AND ECOI.OGY -BLOCK/STEEL PLATE DAM TO BE ,...-... RELOCATED AS CONSTRUCTION PROCEEDS ·LILI ALONG CREEK. · ....!., T G 10 • I STREAM ')-j 'BUFFER (165 ' WHITNEY f JEFFREY WALKER 151 5 S., MAY VALLEY RD ,_ ·- ~r~ciiDE OF SOIL ORYINO AREA. ffi +~----~ 090SB 01-2010 ., ... APPRCMD: DON N...-... ---P.E. 9 12011 ~ King County MAY OW<. DRAINAQf: IMPROVEMENT SHEET FED BOOIO """""" KING COUNTY 01-2010 ~ • . SUIM.Y EMS£ ~ COUNTY 02-2010 iREVDR CRAY, PlS 02 2010 -DALE NnsoN I ,,2-2010 •• -.. ' NUll.j Rlml 8'( OIJE PROJECT KCF'CZD No. .......... DOUG C1t1N 912011 PROJECT No. ·-OALE NELSON 912011 SURVEY No. DESGN EN1ERm: M. RADllLA 9 1 2011 MAINTENANCE DMSION No. 9A1205 • Depertment of Natural~ and Pmta Water and Land Resources Division -----... ---Tii\!J'O!IAlli' B!iJ&.ON 18(!) SBX!!B'fl'A'IICH oo:\l1R01. Pl.AN, l.Ell2lM) 5 OF 10 SHEETS 200a-1a -------~----------- - h -~···~ \_ \) ~. ·-... -; ) ~ ( C ~ '~ . . ~~ .'~' '.).:.... ..... ~.... -err; - Y_f'·s;,-. __ , " -·- \ \ / FlEU) """' ,/ ,/ ,/ 67lC '°" 10X 5X BX 2ll 20ll 30X JOX 10ll 10ll 09D58 SUM'l'ED: KINC COUNTY SURYEY BAS£ W,fi!:INQ COUNTY CHECl<EI> WETLAND AREA Dwarf Tall Feacue Seaside Colonlol Bentgraas Meadow F oxtaU Wntem Mannogran Red Fescue Clover UPLAND AREA Dwarf Tall Foscue Dwarf PereMlal Ryegrasa "Barday• 01-20101 01-2010 02-2010 ..... Red Fescue White Clover Coklnlal Bentgraas _,, -I I TUR61D WATER DISPERSION AREA: TO PROMOTE INALTRATIDN. USE A PERFDRA'Tm PIPE MANIFDUD OR EQUIVALENT TO DISPERSE DISCHARGE FLDW OVER THE ARcA THE SEDIMENT DISPOSAi. AR£AS WILL BE STABILIZED USING lHE UPlAND AREA EROSION CONTROL SEED MIX SPECIFIED ON THIS SHffi, TO MINIMIZE lHE REMOBILIZATION OF lHIS MATERIAL PRIOR TO SEED GERMINATION, A S1LT FENCE WILL BE INSTALLED AROUND lHE SEDIMENT DISPOSAL AREA AND WILL BE REMOVED ONCE lHE GRASS HAS REACHED 80ll c~ APPROY£D: DON AL.THAU--P.E. 912011 PRO.EC1 DOUG CHIN 912011 KCFCZO No. -PROJECT No, """""" DALE NILSON 912011 SURVEY No. I DESIGN DrnRED= M. RADEUA 9.12011 MAINTENANCE I En' I ~ I DMSION No._ ;\ 9.A.1205 • ~---19. ... 210 SCALE IN ' ~ ') '• t ,, ., \ ·\, •, "'·, "'· ~ King County Depm1menl of Natural ROIIIDUl'llal and Parka Water and Land Re:souroes DMsion -----Unit Chtt6 T,w.. Dhcmr '~~. " ,/ <,, >,., fr- !; I; ' SHEET 7 MAY QE8( CRAJNAO'! IMPROVEMB\rr OF 'le lEBC SBXYS\IT IXill'OIIAL. SHEETS N<D llJl!il) 1:JATBI b.Jl iJ\iLCm LOCAno;,e 2001S-11S1 - ~ TEMPORARY EROSION ANQ SEDIMENT CONTROL NOTES; 1. !HE IMPL£MENTATION OF lHESE ESC PL\NS ANO !HE CONSTRUCTION, MAINTENANCE, REPLACEMENT, ANO UPGRADING OF lHESE ESC FACILITIES IS lHE RESPONSIBIUTY OF 1HE CERTIFIED EROSION SEOIMENT COIITROL LEAD (CESa..) UNTIL ALL CONSlRUCTION IS APPROVED. 2. 1HE BOUNDARIES OF lHE Cl.£ARING LIMITS SHOWN ON THIS PIAN SHALL BE Cl.£ARLY Fl.AGGEO BY SURVEY TAPE OR FENCING, WliERE DEIERMINEO NECESSARY BY ECOLOGIST, PRIOR TO CONSTRUCTION (2009 SWDM APPENDIX D). DURING lHE CONSlRUCTION PERIOD, NO DISTURBANCE BEYOND lHE Cl.£ARING LIMITS SHALL BE PERMITTED. lHE Cl.£ARING LIMITS SHAU. BE MAINTAINEO BY 1HE CERTIAEO EROSION SEDIMENT CONTROL L£A0 FOR THE DURATION OF CONSlRUCTION. J. lHE ESC FACILITIES SHOWN ON THIS PIAN MUST BE CONSlRUCTEO PRIOR TO OR IN CONJUNCTION WITll ALL CLEARING ANO GRADING TO ENSURE lHAT THE TIRANSPORT OF SEDIMENT TO SURFACE WATERS, DRAINAGE ~ ANO ADJACENT PROPERllES IS MINIMIZED. 4. lHE ESC FACIUTIES SHOWN ON THIS PIAN ARE lHE MINIMUM REQUIREMENTS FOR ANTICIPATED SITE CONDmONS. DURING lHE CONSTRUCTION PERIOD, lHESE ESC FACILITIES SHAU. BE UPGRADEO AS NEEOEO FOR UNEXPECTEO STORM EVENTS ANO MODIFIED TO ACCOUNT FOR CHANGING SITE CONDmON (e.g. AOOmoNAL COVER M£ASURES. ADDITIONAL SUMP PUMPS, RELOCATION OF DITCHES ANO SILT FENCES, PERIMEIER PROTECTION, ETC.) AS OIRECTEO BY lHE PROJECT ENGINEER/ECOLOGIST. 5. lHE ESC FACILITIES SHAU. BE INSPECTED DAILY BY 1HE CERTIAED EROSION SEDIMENT CONTROL LEAD ANO MAINTAINEO TO ENSURE CONTINUEO PROPER FUNCTIONING. WRITTEN RECORDS SHAU. BE KEPT OF DAILY RE'IIEWS OF lHE ESC FACILITIES. 6. WHERE APPROPRIATE, AREAS OF EXPOSED SOILS, INCWOING EQUIPMENT ROUTES, lHAT WD.J. NOT BE OISTURBEO FOR TWO CONSECUTIVE DAYS DURING lHE WET SEASON OR SEVEN MYS DURING 1HE ORY SEASON SHAU. BE IMMEDIATELY STABILIZED WITll lHE APPROVED ESC ME1H0DS (e.g., SEEOING, MULCHING, PLASTIC COVERING, ETC.) 7. TEMPORARY PAlHS USED FOR EQUIPMENT ACCESS WILL BE RESTOREO TO ORIGINAL CONDmONS ONCE CONSTRUCTION IS COMPLErnl USING lHE APPROPRIATE UPLAND OR WEllANO SEED MIX (SHEET 7). ONLY TRACK VEHICLES OR APPROVED EQUIPMENT ARE ALLOWED BEYOND ACCESS, LANDINGS ANO STAGING AREAS. B. ISOIATE MAY CREEK FROM CONSTRUCTION AREA BY USING COFFER DAM, AS DETERMINED FROM SITE CONDITIONS DURING CHANNEL EXCAVATION. INSTALL A CLEAN SUMP UPSTREAM OF COFFER DAM ANO PUMP FROM SUMP TO SUITABLE LOCATION AS DETERMINED BY ENGINEER OR ECOLOGIST. 9. SEC0Ntl6.RY PUMP WILL BE USED IF EXCESSIVE GROUNDWATER IS ENCOUNTERED DURING CONSlRUCTION. SECONMRY PUMP WD.J. BE ON SITE AT ALL TIMES. 10. PUMP SYSl[M/5E:IUP TO BE AELD ADJUSTED AS NEEOED AND DIRECTED BY PROJECT ENGINEER/ECOLOGIST. 11, REINTRODUCE STREAM FLOW TO lHE EXCAVATED CHANNEL SLOWLY. DO NOT REINTRODUCE FLOW INTO THE EXISllNG SlREAM UNTIL lHE FLOW MEETS STATE WATER QUAUTY STANMROS. PUMP TURBID WATER TO lHE DESIGNATED VEGETATED UPLAND AREA OR A BAKER TANI<. 12. MOVE PUMP SYSTEM/SETUP DOWNSTREAM AS CONSlRUCTION PROCEEDS ANO AS DIRECTED BY PROJECT ENGINEER/ECOLOGIST. 13. MONITOR MAY CREEK UPSTREAM AND DOWNSTREAM OF 1HE CONSTRUCTION AREA TO MAKE SURE lHAT STATE WATER QUAlJTY STANDARDS ARE MET AT ALL TIMES DURING CONSTRUCTION ACTIVITY. IF WATER QUAlJTY lHRESHOLOS ARE EXCEEDED STOP CONSTRUCTION ACTIVITY ANO MODIFY BMP'S TO BECOME COMPLIANT AS OIRECTEO BY PROJECT ENGINEER/ECOLOGIST. 14. PRESERVE EXISTING NATIIVE VEGETATION IN CLEARING AREA UNDER DIRECTION OF ECOLOGIST. WELL VEGETATED UPLAND AREA PUMP -SUMP (AS NEEDED) PERF' PIPE ECOLOGY BLOCKS· ~;I§ff:;~(o~~Gph;. TO STABLE CHANNEL_,~--t (DOWNSTREAM) -' -. .._.. . .•. . . ._ ....• GRADE SUMP AS DIRECTED BY lHE ENGINEER OR CESCL AS NEEDED. CESCL SHAU. INSPECT SUMP DAILY TO DEIERMINE IF SOIL IS SATURATED. IF SOIL IS SATURATED PUMP EXCESS WATER TO TURBID WATER DISPOSAL AREA. PUMP WILL BE ON SITE AT ALL TIMES. IF TURBID WATER DISPOSAL AREA BECOMES SATURATED PUMP TURBID WATER TO BAKER TANK. SOIL DRYING SUMe DETAIL NlS WASHED GRAVEL~ 1"-1j" ROUND PERFORATED 24" • PIPE/RISER ALL MATERIAI.S SHALL BE REMOVED WHEN MOIIING TEMPORARY CHANNEL BYPASS PROFILE 24"• RISER DOWNSTREAM COFFER DAM AND PUMP. SEE NOTE 11 lHIS SHEET. / UPSTREAM COFFER DAM :l, 02°110SECONDARV PUMP (4" PUMP ON STANDBY""°'\.~ FOR WET CONDmONS) "· DISCHARGE TO STABLE CHANNEL. BEYOND ACTIIVE WORK AREA (DOWNSTREAM) eJ.AH -·· "> =---.. ,~ _FLO,r_ . ... ,,,,.'i,,.,;1,_, ...... 11 .. ~.1 .. ,,.~-. -·~~~ 4" PRIMARY PUMP (6" PUMP ON STANDBY FOR WET CONOmONS) PLAN AND PROFILE VIEWS TEMPORARY CHANNEL BYPASS PUMP, DAM AND PIPE DETAIL (TYP.) ffi .... """"' OBOSB J 01-201 StaMYED: KING COUNTY I 01 2010 SWMY BASE l,WIP_NG COUNTY 02-2010 °""""' --IIY I ..,. APPROWD: DON M._,., __ P.E. 9 12011 -DOUG CHIN 9 1 2011 KCFCZD No. ........,. PROJECT No. _ ·-DALE NELSON ".,_,·11 SURVEY No. I DESGN DfTERElt M. RADQ.J.A 9"2011 MAINTENANCE OMSION No.- 9A1205 • NOT 10 SCALE 5,6 ...__.. ~ King County Depe:rtmenl of Natural Raoun:.a Ind Pmb wa1t1r and Land Rasoun:es DMslOll -----.... Cllrldt T11111, Dtn,cto, IC DAAINAaE ll\lPROVEl\laIT TEl\!1'0lWW EFt0!!0:11 AND ~ATIOlll l«JIEB Na, D21'AIUI SHEIET 0 OF 10 SHEETS 200S-1S ~·'" -"\'tlG \\Op!) .;i-\'='" ~ INSTALL DRIVEWAY CULVERT IF THERE IS A ROADSIDE DITCH PRESENT, PER KING COUNTY ROAD STANDARDS PER KING COUNTY ROAD STANDARDS, DRIVEWAYS SHALL BE PAVED TO THE EDGE OF R-0-W PRIOR TO INSTAUATION OF THE CONSTRUCTION ENTRANCE TO AWID DAMAGING THE ROADWAY. IT IS RECOMMENDED THAT THE ENTRANCE BE CROWNED SO THAT RUNOFF DRAINS OFF THE PAD. 4"-8" QUARRY SPALLS-J~v GEOTEXTILE ~ u: h\ UNIVERSAL CONNECTORS ,. In I FLOTATION I, TENSION CABLE BELOW FLOTATION GROMMETs LACED TOGETHER WITH MANILA ROPE CLEAR Pl.ASllC COVER ' UNDER SPALLS L 15 MIN. ...........__ PROVIDE FULL WIDTH OF 12" MIN. THICKNESS /' INGRESS/EGRESS AREA ~ ~ 24" SAND BAGS O BOTH ENDS TO ANCHOR PLAS11C ~UAIU TC'u,..1n~1~ ...._. .. STRESS CONSTRUCTION ENTRANCE ffi BALLAST CHAIN PLATES, VIA HOOK AND RING CONNECTION NOT TO SCALE 5,6 '-" Slll_CURTAIN (TYPICAL) IC_ 5 NOT TO SCAL£ '-" ·-··-· .. -· JOINTS IN FILTER FABRIC SHALL BE SPLICED AT POSTS. USE STAPLES, WIRE RINGS, OR l EQUIVALENT TO ATTACH FABRIC TO POSTS --- 11 11 11 ---+--X X )C X xi X X -t--- ---1---X X X X ,4 X X -+--- T X X X X 1 X X .,, / / ., / , ... • ;' • ,. ' ' ? / '. ; ;' / • >-,-'/ /' '/ / • •,'~ ·, -, './/y /"\ /--:</ ,'! /.'v//'-.(,. '., ,'/ .. -·/' / / .. / ,, , < •' / "/ ,,., ...,,__,.,,,~ '\ ·'' ;,' .. ,, . ... . •, '-;,'"/'-'"'''j'" .,,, ·,, ·./ / ' .. / ,. ,,, / ', . . './'' . . .' .' ' ~ .. -'-' , / ' /' .. "'/ /-.!/ '. ,J. ,'/ ·0<//-;','.:-<<'//\J/'." '/-, /;, / // '/"· // ,· /~ ', __ -~ ,,<)"',,>.,,~;;;::;...'>-'~';\.."'-j-..':--.)r,',>: ,', :"', ',J. ,,, :;.-,"'~ /. '·>\.''<"/'.~-~/: ,-~;' -· -/ .'/ // "%:<,;:(/j:CsARBEo • WIRE FENCE ---/, /dn<: ( ~~:::: 11 11 JI 2"X2" BY 14 Ga. WIRE OR EQUIVALENT, IF STANDARD STRENGTH FABRIC USED FILTER FABRIC· NOT TO SCALE 1 4 r: :i "' '-" BARBED WIRE FENCE INSTAUATION NOTES: 1. INSTAUL ON PERIMEIER OF WETlAND MmGATION AREA PER SHEET 14. 2. INSTAil. ON PERIMEIER OF CONSERVATION EASEMENT, BOTH BANKS, FROM STATION 7+50 TO STATION 2B+DO, 3. USE EXISllNG PROPERTY FENCING WHERE AVAILABLE. NOTE: FILTER "°'""'"'~'~?'----"""""""BS:"-~~ FABRIC FENCES :l'hM·Y./#'/A,V/,-~7&/AV/;:-/'/;;J'/),,>f')>Y'A SHALL BE INSTALLED I I I I ALONG CONTOUR WHENEVER POSSIBLE 2•x~• WOOD POSTS, z :i 'l. POST SPACING MAY BE INCREASED STEEL FENCE POSTS, TO 8' IF WIRE BACKING IS USED REBAR. OR EQUIVALENT _SI_LT F_ENCE NOT TO SCALE f1ElD BOOK, 0905B I 01-201 SUIM'lm KIHG _COUNlY_J -~_J1,-20l0 SWM.Y IMSE ~G COUNTY I 02-2010 02-2010 ""°"""' - ffi 5,6 '-" APPRCM:D: DON ALTHAUSER, P.E. ~ DOUG CHIN om:NED; l:W.E NELSON _il2011 ~KCFCZD No. ~ PROJECT' No. """" """""' M. J!AOO.LA I •120 I 9/2011j SURVEY No. MAINTENANCE 111 DMSION No. NUIL -sr_ I cm 9A1205 4 \ \ \ MAY CREEK \ .. -··-··-··-··-··-··-··-··-··-··-· H L 2·-0· J'-0" i'=-g_· e·-o· w 'J.'-f)· 2·-0· METAL LIFT RING SECTION TEMPORARY EROSION PLUG AT CHANNEL ALCOVE GRADING. NTS / VISQUEEN OVERLAP AT JOINTS A MINIMUM OF 1 FOOT. 3 , / ,r.///• : •' ; .·-. . /~ / ,,,. /' ,,,. · • .-;·. • ' ~ ,: .r ,,. •• MIN. DRAIN ROCK ~ 5 '-" m,---r,...,~ / , / / / T :.. ·:-.· · .. ;~ •;.:•.-: .. t,·,·.,;..: .. · "'· · • \~ ., / .,,. .,.. ,,. _,,.,. .,, BACKFILL AROUND s· ' ~·--, •• · -• . • . : ·, -' -·:-.-.· : ·, •·• : / / DRYING SOIL' /, / PERFORATED PIPE WITH ·, . . •. : .... : •.. .;. ... • • ~ I . / .,.. FILTER FABRIC WRAPPED J_H ·.:':;:: ; < :; ': '_;:· .. :, .\/: 4'j_HIGH .• , :_-, ,; 1 , / / / ,,-,,. ,,. / ,,-_, AUL SIDES. DRAJN TO SUMP 1'>'} : + " ~· · ---2':t ,: .~ , , '~'.;~~c~;;; CONCRETE TONGUE AND GROOVE BLOCK »>0~0'>:-;,',/));.;':/J_y'-))~:) 7,~~ / );;/,~? SOIL QRJ'ING CONJAINMEtiT ____ -rr NOT TO SCALE ~ King County Department of Natural Recaun:a and Pab water and Land Resourrm Division ---Capllaf 8oMcao Unit a,,,.-- 5,6 '-" K DRAINAGE li\tlPROVEMall' m!l'CllARI' m AMD ~CXMRCl. DST'A!UI SHEET 9 OF i9 SHEETS 2008-18 ;..;;;.: - / (- \ -\ f~~ ) ,,§-= ~·~ ' .,.. ------' ~ = '"-------.__ ; : i ' ---/,_____ $_--~ ~ I ~~" REMOVE VEGETATIO.N 06STRUCTING CHANNEL Fl.OW ANO REED/CANARY GRASS AT lHE DIRECTION OF ECOLOGIST OR ENGINEER PER VEGETATION R MOVA!. CROSS SEC110N DETAIL ON SHEET 15 AND TABLE 2 ON lHIS SHEET. = = = = = g NOTES: 1. SEDIMENT REMOVAL FROM STA. 5+40 TO STA. 26+26 2. STAGING AREA SHOWN ON SHEET ~GA'(:;;:::1 PROPER1Y) = = = = ~411::Ji;::::I ...... == == " ...... PRUNE IN STREAM VEGETATION AT STATIONS LISTED IN TABLE 1 BELOW AND PER VEGETAllDN REMOVAL CROSS SEcnON DETAIL SHEET 15 I::;:;, q =:ii c:I a;I c::o c::;:I ' , C:2 c= c:=sa:::ll ~i:::11ii:::=1c:::a TABLE 1 TABLE2 Stationing of the In-Stream WIiiow Pruning for May Creek Stationing of the In Stream Reed canary Grass Removal Station From SlatlOrl To Station From Station To t 0+30 0+70 1+50 3+00 4+50 4+90 26+26 29+00 315.0 ,. ~ 11111- 310.0 \ TA8LE3 -~-? ,""-1l .~ Stationing of Sediment and Vegetation = Removal Station From Station To 5+40 26+26 ,___ __ ,v ~ 'PROXIMATt STREAM IBED ~ = = R£M0VE SEDIMENT STA. 5+40 TO 26+,26 SE£ TYPICAi. SEcnON SHEET 15 j ,::::::> • " II . C::::::, .!I! ' JD_ SCALE Ill FEET ffl~' ,~ me !!jZ ,.m .. tn ;;! I __ J/\ .~ I 148TH I BRIDGE A/ID FOO_TBRIOGE ~ 315.0 310.0 --...-:-: -,.,.__ :;-----·-· --,_ -·-----·· ----~ :::j ~-: l !J!~VA])o_N cioF1t£ i r_e: ~1-. i=-....-~ I ].- ------305.0 --·-305.0 DO !NOT GRADt IN C: 300.0 I t I I t I I t t t t I I I I I I I I I I I I I I I I I I I 300.0 -0+90 -0+60 -0+30 0+00 0+30 0+60 o+90 1+20 1+50 1+80 2+10 2+40 2+70 3+00 3+30 3+60 3+90 4+20 4+50 4+80 5+10 5+40 5+70 6+00 6+30 6+60 6+90 7+20 7+50 7+80 09058 01-2010 ~•• -·- FED"°"" . ' , KING COUNTY 01 2010 T SUIMYEI> • • • SUlM.Y ~ ~G COUKTY 02 2010 - lREVOR CRAY• PLS 02 2010 CHECICE>. ,.. .. ,r-NnrnN ""-""1 ~ .. ·-·· , , ... 1 ......... "' L-.Di\![_ APPROYED; DON AL1KWS£R P.E. 9"2011 PROJECT KCFCZO No. -DOUG a-DN 912011 PROJECT No. 9A1205 """""" llALE NB.SON 912011 SURVEY No. DESIGN ENtERED: M. RADEi.LA e .... 0,1 MAINTENANCE DIVISION No. 4 ~ King County Deparlmmtt af Natural R89CIUlte$ and Parb water and Land Resouttes Division -----Unit --- CALL 2 WOl'll<INQ DAYS BEFORE YOU 0:0 1-800-424 5556 (IJNtlERCROUND UTIUTY l.OC4TIDNS ARE APPROX.) MAY QiLll CRAJNAQE IMPROVEMENT SHEET 10 Pi.AN /ll(IJ Pi!Dl'!I.E STA otCIO 10 STA IHOO OF 10 SHEf:TS 2006-18 w ·.-, \\ ------\~ \ r\ '-.,\ ) \~ = = \ \ '==~~'~=~= \ C-~ -~ ~•U 9Uff[R ' ,,, \ \ \ -/\ ~,,..,.. '-·· \ (,1 \. \ /&_ Nam ., , \ '---'I' g • IMPACTS TO MATIJRE VEGETATION WILL BE MINIMIZED \ ----'i' + OR AVOIDED TO THE MAXIMUM EXTENT POSS/Bl£ ----u. CIII UNDER THE DIRECTION OF ECOLOGIST IN lliE FJELD. \ r ----- !I( NO MATIJRE lREES SHALL BE REMO'YEO. -'i' 1-INSTALL 3-STRANO BARBED --, 0c, • METHOD TO AVOID IMPACT: APPROXIMATaY E.VERY WIRE FENCE Willi T-POSTS; \ IU .. 50 FEET, AT ONE SIDE. EXCAVATOR WILL ACCESS CONNECT TO ~STING FENCE ':E\ ;J: I-CREEK AT lliE DIRECTION OF ENGINEER OR l>S NEEDED TO DELINEATE 0VE SEDIMENT \ :JIU, ECOLOGIST. SEE BELOW. BOUNDARY OF C0.NSERVATION STA. 5+40 TO STA. 26+26 :Z: ! El>SEMENT SEE lYPICAI. SECTION, SHEET 15 0 II = I ~11111 = \ = ~ ~ ~ I I I I" : ,,. I 11 o ~ 10 ID \\ SCAlL IN FEtT = = = = ~ e"' i --1' 5t/JJ g g I :! ·x-.:l!Er,, g + , _,__ + L--'V .,, ~ = :'Q,-=-= ="" ~ j ---g + C'-1 ---~ ~ c::i ,r;::::11 ,,"4--.c;J' ---'V: .,.--;;:_ + -~ = = = = = ·· ;:-;, 5EE SHEETS 18,19 :y . c:::t:. -~ X o x 1( X 1:=::1 ~ ~ c:::11 pL.ANTlNG MffiGATION -.. -... ~· ---'~ ~ , c:==:t .i:z=::a .;; X X X c::::i c:ll s=::a ~ m ~ c:::a ci::=a c:=. c:r c::i •· 1, ; r-- C3 c=t ~::t ==-c:::a PL.ANTING MmGATION BUFFER ---- ; -• -••c=:t c::a ~ c:=i c:::i = ,. c:::ac= !='i,:;:s J::::I~ i::::,c;;:1 ~c::s C:':I=\-=::::, ~ \' ~ ~ ~ ' . __..,. i ~~ C lAN!lNG MmGATION -SEE SHfE!S 18,19 "" ':;!.. =~ ~· '11 ___ ,v_ \jl ~----->g ""-....11- ,:;:s c=a c::a c:::a X c::, i:::=:11 i::::::i>C cO.. c::::::a~ X c;;:1 ~ !;;! X c:=a ='\ ~ ---.......... 1r,,.;:r_;:=:_ X ~:=.....:_:::-x . \v---'il-. IN CONJUNCTION Willi SEDIMENT, ALSO TEMPORARY ACCESS LANE 15' WIDE. 4// REMOVE VEGETATION OBS1RUCTING CHANNa \ SPACED APPROX. 50' APN{f (TYPICAL). . / -FlOW ANO REED CANN« GRASS AT lliE \ \ EXISTING VEGETATION BETWEEN LANES -11 / DIRECTION OF ECOLOGIST OR ENGINEER PER \ WILL NOT BE DISTURBED. ACCESS LANE .. CROSS SECTION DETAIL SHEET 15 Al.ONG \ WILL EXTEND FROM CREEK TO EDGE OF ~ "---'V 'V _____.,,..... STATIONS 5+40 THROUGH STA 29+00. WILLOWS. ACCESS POINTS Will BE / DIRECTED IN FIELD BY INSTALL 3-SIRANO BARBED REMOVE AND FROM CHANN~:N GRAVEL PRIOR TO SEDIM QITOM ' ~{IEMOVAL EN1> AND REPLAC°?~~fAVATE CHi\NNEL TO -VELS IN ENGINEER/ECOLOGIST TO AVOID WIRE FENCE Willi · T-POSTS; A , OISl\JRBANCE TO MATIJRE lREES. OFF CONNECT TO · EXISTING FENCE o UV JO a "----ROAD EQUIPMENT REQUIRED TO l>S NEEDED TO DELINEATE _.,, ~ GRAPE. APP REACH ANAL • /' '~"' m .~~-~"' = ~ 0 Jllloif'.1 3 no-...-:·/"-----------~ = ---"~ -"""'-_, •.. , .......• ···-"'""" ""' . MINIMIZE SITE IMPACT TO INCLUDE BOUNDARY OF CONSEft\lATION = •= = = = =' '$• .,=-,= = ·----•. , ~o·o••"'' = ----·~ \ TRAa<ED EXCAVATOR, OR EQUIVALENT, El>SEMENT -. ... ----___ -·· = -·~- \ ANO TRACKED DUMP lRUCK OR , EQUIVALENT. . I -EXISTING FARM FENCES TO BE TEMPORARILY RELOCATED ANO RESTORED EXISTING GU'IWIRE -f-t---\:.~ p15.o f+BTH RBliGE plO.O _-. OOTBRIDGr AND =::, = \ AFTER CONSTRUCTION __ ::, ~I = ,ec:, ~::, _,. ""~ I ./ ·-= ., ~,, - ........ ,.............. ..-~ --___ .., -c= =>·'<" --?>·"' '°""" •• • --•• ' CALL 2 WORKINQ DAYS BEFORE YOU DIG 1-80CH24--5565 {UNOERCROUND. llf1UIY LOC'Al!ONS ARE. N'PROX.) NOTES: 1. SEDIMf REM)~ FROM . STA. +40 TO A. 26+2, 2. STAG1 G AREA S OWN ON JsHEET 5 (SEGAY nvr '1" I T J l?:'f H9R 315.0 1·-\1!R - ~--.. f fTING SEqMENT -+---r----+ Wf~tEAMB$ I-. -< --~~-7" i-:. :-: ... t =t-=t=· t---::::i=-1--310.0 ··--... ---· 1--.-lY15."'=v .. ,_.-- EXCAVATI4>N PROF! ··t-,,-.1.-·· .-· ~ 308' r--.. - 7+50 7+80 8+10 8+40 8+70 9+00 9+30 9+60 9+90 0+20 0+50 1o+80 1+10 1+40 1+70 12+00 · 2+30 2+60 2+90 13+20 3+50 3+80 4+10 14+40 4+70 5+00 5+30 15+60 5+90 6+20 ~ -~ FIELD BOOK, 09058 01-2010 .-.. -• 5lllM.'IE> KINC COUNTY 01-2010 • ~ • • .. SUIMY BASE ~G COUNTY 02-2010 TREVOR CRAY, P1S 02-2010 CHECKED: -I ~ NELSOM I--_ .... , -~. ···-.. _, ~ -"' - APPR<MD: DON Al.11WISER P.E. s---11 ........ ......... OOUO CHIN 9--11 KCFCZD No . PROJECT No._ 8A1205 """"'°' DAU: NELSON a •2011 SURVEY No. OESGN DI~ M. RADRLA 9 -011 MAINTENANCE DMS10N No. • ~ King County Department of Natural ROIOLIICleD and Pmb Waler and Land Resources Division ___ ....., __ Clldde T,w,. DflrK:to, MAY Ciifll{ DAAINAO'E IMPROVB\E\IT l'I.AIII #{J) PitOl'!l.E STA &Kiil 10 STA 1a+aO SHEET 11 OF 10 SHEETS 2008-18 I I I I I I I ·1 I t I I I I I ~ I :B I iC I . :r I ~ I : I: I 0 -- :,.-01' ~~DooooaotrrniQoo 0 ~~- 0 00'0 """ tl~.3,.°' •o ' " " " ,i/ A( I .,-1· -~\l / NOTE: <::::::, = ___, '1-= = <::::::::, <::::::, <::::::::, <::::::::, <::::::::, t::::::::::, 1-.i o-o-°' ~,I'> 0 WEltANo BUFFER I • IMPACTS TO MATURE VEGETATION WILL BE MINIMIZED OR AVOIDED TO THE MAXIMUM EXTENT POSSIBLE UNDER THE DIRECTION OF ECOLOGIST IN THE FIELD. NO MATURE TREES SHALL BE REMOVED. 1~1111! L, ... t,~ JI "' 317 5" 0 .,-4 ... er di#' t? f r--;:.; ~,:: • METHOD TO AVOID IMPACT: APPROXIMATELY EVERY 50 FEET, AT ONE SIDE. EXCAVATOR Will. ACCESS CREEK AT THE DIRECTION OF ENGINEER OR EC0l0G1ST. SEE SHEET 11. SCALE IN FEET '!>''I- SIRAND BARBED ._,_, .... M_m""a,u ~.,:._,~ . "'--.--.-.. --m-= ' / ~•-m~ ) 0 LBOUNDARY OF ~ _; 0 8 0 0 ---------t---• . ll .. , ~. """ "" ...... --. • '" -.,_ ,,_ -----·~,. ----·-----'-~,..,_ 0 --' -,_ '~ . -----,,__·~ . -~ ---,, ,_ " .. _ ---.. -.... . --~._ 0 -·--.. -• -. --- --,ye .. ' ' , .• , -·· -.. .. _ . ~ ---.. ::..:c· "·· ' . "'l"' ~ ..... ' ' '-,,_, "'·--· .-'"'-,-- -·~ '< -------_,_,, __ .,_ ----~....._ -;.··:._ ---~,· .. ~ . ' -' ---• ----=-., • --.cc,. _,._._ ... - ' --·-= -.......... -. -' ' -"'-. 4' ·-'£':: ''""";, --""=. -· f .... ~?~ 'al'-"""-· '~---~m~~ '"----~.~~ ' ~· -m=•-~ =----' ~-~--~·::c-'11,,._ • ---\ :::::.'ll/1 "' ="''"'"::I~~• =u ,'1 --~SM "~ ""'""' V, --:,£\-------v,~ ------"'------I,. J12 " '31,1 '-• -, --!:! ., '"',.. 1:,:fii ,if ,'/:!"' fl ~ . --. -:i L-:.::i J"1..? .. -, c::.::::i .._,_ -, -c:.:., .C"-.:J ·--' ·- lfS ·-=~ •, I.<-! c::::i •• ""'" r::-_;"-J c::".:;_;i ~ c,:::.:l ,_::-\'-·., . . JIJ = ' -------. .,_ ---'-•-:::::,::::::::::.--... , ' -p . ------e::. ---· ! 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' Pl!Q.Flj.!':..::.. 3!)8T l -' po NOT Gj!ADE IN qiANNEL op.ow El.EVf,110N 30[} . . . -4-. .---i_ . 305.0 oq NOT GRAPE IN cH1,>ma BELVN ELEVA'JfON 308 - 300.0 15+90 6+20 6+50 16+80-17+10 --7+40 7+70 18+00---i!+30 8+60 8+9019+20 9+50 9+80 0+10 2o+40 0+70 1+00 1+30 21+60 1+90 2+20 2+50 22+80_ -3+10 · 3+40 3+70 24+00 4+30 4+60 CAU. 2 WORKINQ DAYS BEFOl'IE YOU DIG ~ (UNDlRCROUND unutY l.OCA110NS ARE APPROX.) -~ 09058 01-2010 ~ .. N'PRO\O: DON Al.lHAIJS P.E. 9 2011 . ~]King County MAY au:& IJAAINAQE IMPROVEMENT SHEET KING COUNTY 01-2010 • -KCF"CZD No. 12 . • ......... OOUO CHIN 8 2011 ~ SU!MY aw: ~NG COUNlY 02-2010 PROJECT No. 8A12D5 Departmlnl Of Natnl Raoun:et end Parb: OF Water and Land Resources Dlvi$ion 'S TREVOR CRAY, PIS 02 2010 -DALt NE!SON 9 2011 SURVEY No. stDffnwater Setvlc:a 6edlDr'I -,,,_ .. --· ,,_ ~ ·-·· --.... ., MAINTENANCE Pl.AN AINI) Pl!Ci'II.E SHEETS _, ODDI EH1£Rm: M. P.ADWA • 011 DMSION No. • """""'--Sl'A l&+ll010 Sl'A lMIOO ........ "' .. ,. 2008-18, ,_;,i """ r,-, ,.,, ~·c·;Jl !"./,l """' .. •.. .., ;::, 11 I I I I I 1:f·W I I I 30 0 311 10 IO ~ = SCM.E 1H FEET = c:::.:::::, c::::::::, ~ <:::::, ~ IN CONJUNCTION WITH SEDIMENT, ALSO REMOVE VEGETATION OBSTRUCTING CHANNEL Fl.OW ANO REED CANARY GRASS AT THE C:::::, ~ DIRECTION OF ECOLOGIST OR ENGINEER PER CROSS SECTION DETAIL SHEET 15 ALONG STATIONS 5+40 THROUGH STA 26+26. .,, INSTALL 3-STRANO BARBED MRE FENCE WITH T-POSTS; CONNECT TO EXISTING FENCE ~ AS NEEDED TO DELINEATE BOUNDARY OF CONSERVATION EASEMENT -1 ~PACIS TO MA: ~ATION MLL BE WNl:rLEO - 0 ~ <> II t---- ,.; OR AVOIDED TO THE MAXIMUM EXTENT POSSIBLE '<,j. / .._ UNDER THE DIRECTION OF ECOLOGIST IN THE FIELD. " <> II ------NO MATIJRE TREES SHALL SE REMOVED. <f>i;; / .._ /. ~<> ---• METHOD TO AVOID IMPACT: APPROXIMAlELY EVERY <.)' I._ f / :... so FEET, AT ONE SIDE. EXCAVATOR MLL 1.ccESS "' "" o O /} .._ / / ~ " CREEK AT THE DIRECTION OF ENGINEER OR <l< .._ .._ / / -, ECOLOGIST. SEE SHEET 11. ¢¢ .._ / / / ' II-,¢0 -------1 // ~-'<::::::----11-!J <>" ~ v r ,,, ,r ', ........__ " I " '· ---.._11-I} I ,, ',, ........__ ~ su,.,_~~ I ,? ', ---.._ "· o . re~ r I I ,, ' . ~ // ',,, --------II-'·::J' ..._ fl ~ ~,:, , -....... ,,. ll "' t I 11 =:::i ', .......__ii I \ O ~ Sll!~..,..se:::, ',, 11-I\;; , -'i. I 11 ,:, .• "" t:::::::, ', 7 '\ ''-. a / // /t;q___ ~ · \ li ·, / ,f' 8t, r!f/ '-. ',,t::::::, L \ 'i'i / / ~ , 0 a , 0 -.._ '-. "'"" r< ~ / I/ SJ ~o « ,h .... -// <> ·4; ',, -6 \ a / ,:, .. o (! ';I '-.... \ ~. y I/ <;, ' I/ -' '.S ' '\. d· I/ V .,~ ~,., "°1o t::::c, 0 .,:; , 0 // O ... ~ , ''-{ "-o I I ,, ···-<> /) "" , '-men ,0 ,, o REMOVE SEDIMENT STA. 5+40 TO STA. 26+26 !!J ~ · Z, ~ -v;--,f f '.' 2----~ <> 9 SEE lYPICAL SECTION, SHEET 15 .., t ,, £ 0 I' "\, ',-/' ~ --1 00 ,_ , -0 ,ii I er,, a/a.,,'· K> fr !O l ',,"'-~ Q\ / f 'll"'a+i,ooor, ' ------~ (~ C'.li~ ', "'-I"' 0 1""' \ " ~ " i:@ ', tt. n / / {; "-·-....._ ~-,.....-! .;;.,~ <Ii o.i ', '°"-lt1, / t l"' --· s----) ... .,,,,, ,, i!'§ \ "'-tt. m I /'' , .-i~ T5.C ~.... . . _,___ °'IJi. 8 \ ~~;.c 1' I I~ f -~ " ' ' · ---~ • ;!: ' GI /J~ . , . = I ·£f /-le.,.. <=> • • ' .. •• 0 I /t. f . "" ~~ -1'1.wnNG l.ltnG4 •· · · :.' .-•· :--... -~. ~ _ o '---------~ / ~ ,,,-- ->j , ,. • 30'IH111 1·-~- ~ ~ •""·= ,.lloN -. . . . . . . . = ----<-~, I I NSTRUCTION EQUIPMENT J:: INSTALL 3-SIRANO SARSEO~.~HE:£7s 78 ··-'.: ,....,._ . ... ...... -~. ~--, ~ ,../ f I ~LL NOT CROSS EXISTING / ••CV MRE FENCE M1H T-POSTS; •-...:._ 79 -· • --• ""' "'--.-_ i5' b BRIDG I.U .,.. CONNECT 10 EXISTING FENCE c=::a, ~ . --.'.. ' • :---~ ~ .. -:,:I-AS NEEDED TO DELINEATE ··= <:, • -. -· ' ;---""-':;;> ---;7-' :::; Ill' BOUNDARY OF CONSERVATION "" oo,, ----'. , ; -_ 'Y--'j, zi'.:C rASEMENT ic==, ~ C::zty--• -9 , , '· ------\II'. ~ OOJ =~cs;---.,_,/ ,_ NOTE: ~~~ --I •• !C/fl 1. STAGING AREA SHOWN ON SHEET 5, (SEGo\Y REMOVE VEGETATION AND REED CNwif' ..,.., .,._ ·-·--c...-,..,,._;.::, ' Ark"F';:;,-;::---. ·- ;,f; OJ PROPERl'I) GRASS OBSTRUCTING CHANNEL Al.ONG STA. "'-'<!,, ,·'S: . = ~K . · 26+26 THROUGH STA. 29+00 "'> """;=,j ~7 'C·-~ .. ---..::..,, ...._ -.. -- EOIMENT 315.0 nimm~Mil"--t--l-=--'-"'t-'-'-=-4'~-~-4-tsl3-=---_ ~-_ _ . _ ~---= -I I I I I 310.0 l-io5.oJ I . J 305.0 iJOO.i° 300.0 23+70 24+00 4+30 4+60 4+90 25+20 5+50 5+80 6+10 26+40 6+70 27+00 7+30 27+60 7+90 28+20 8+50 28+80 29+10 9+40 9+70 30+00 0+30 0+60 0+90 31+20 1+50 1+80 32+ 10 32+40 CALL 2 WOMINQ DAYS BB ORE YOU DD 1-800-424 5555 IND UTllffi' LDCATIOI§ ARE APPROX.) Fl£Ll) """"' 0905B Ot-2010 APPROVED:: DON ALTHAUSr-1e1 P.E. 9J2011 ~ King County SUIIYE'tEI> KING COUlf1Y 01-2010 ....... a-11 KCfCZD No • SIJIMY 11ASE ...,l!INll COUNTY ......,. DOUG CHIN 02-2010 PROJECT No. 9"1205 Department of Nall.lrel Rmciurcea and Parts Water and land Resoun:es OMsio,i TREVOR CRAY, PLS 02-2010 DEM<Elt llAl.£ NaSON 9/2011 SURVEY No, ---CIIECICEI> tw.E Na.soN 2-0 ---DESu.:N EN1ERED; M. RADO.LA gMntt MAINTENANCE 4 ---NUU. ....... flf .. ,. OMS10N No.- MAY a < CRAINAG'l: IMPROVELVJENT SHEET 13 OF 19 SHEETS l'I.AIII AKI) l'l!DRI.E srA ll4o!Clll 10 srA IIIHCO 2006-16. <IT,~ - ~ l>:C:J &Co!! C·:i'! ~:4 ·Cc·.·sl ' ,t '-I -~<> '-~.f._ '-I ~ o_ .... • I C.AU. 2 ~ DAYS BEi Ol'IE YOU 0:0 H00-424-5555 " "\ -<> , "'J-,,,_ -, I ' <>.:,1 0' 'ft~, aac,Clbaocccca,ooo,, ' . -o" / k <>oo '-, ~..._ '--;. ') Oot:, 0 \ 0 '<l.~ I ',. WETIAND BUFFER ( 75 ¢00 \. O <>o \ '<> I ',. , ~'V·---11,,---....._ Oo'?,,,_,,'~ .:.I <>o \ ' "!;!' q 11 ~-A \. •••• I ', I """ • • • . / . . --~ "\,.-', (UNDERGROUND UTIU'IY • ' ™ • -~ ----'-\ <>o I '{>; ' LOCATIONS ARE APPIIJX.) ....._ l --...._ II,, -_/ "-o<> \ '-' ~ --. <> I ,--,--.,,, '-, --EER/ECOLDGIST PEX 8418 OR '-, 0 '\. '--' . ~ ---~ -~---~="·= . ::;:;:.;::;.::.,~ ' . . 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" ,~ :, ', ' ,c,,, ,, ( ="" '-j 'ALCOVE GRADING o....,!_j' ~ ", N '" ' '., ," ,, " .... a, -.,.,rnro»~ ·=" •. , I tt \ ,. ·~ ; : ; : :;:,"..Cs, ·L, '~-~ -1~0'7!:~N5;~ SEE SHEEr 18. ~ ;' j' ! \ . , I I I /',-< \ I I I - I I 1',, 09058 ~ 01-20101 01-2010 02-2010 NW. .,(C',• :, ·>'.· '.·. -~ec.r:, ., .. '·.1 1, 1, t I l / ' ' , °'..J"> Ceo '' ,#' J'. '· 1 c_,/1,11, ' ~---~ , ii! ' ' . '\ ' I ' I ,, ,¢ , i ! .. } ,rn1,, ' --8'I' I MTE APPRCMn: DON ALTI-WJ! PRO.ECT --DOUG CHIN tw.E NELSON DE!GN EN1ERED: M. RADB.1A e,~ j_/2011 D/~:,, I KCFCZD No. PROJECT No. __ 0/2011 I SURVEY No. 0/:1011 ~~~~- ~ 9A1205 4 c-IJI-i! r1 1 r ~T(1 ,r.'S'-· ~ King Coum:y Decmtment of Natund Remunm and P8lb Water and Land Resources Oio,;sion ---Cllpllal 8onlcoo Uratt --- ,;'.::J f i I c::::J I ! 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G+ -: STA-8;>00-T<Lo A .. 26,1,26' ' ' ""'' • ..:,......,,..._ ' • ~YI IGAi: , T ,:, ·---=l!XISTING ' ' ---!-,,~~ ::::::=::=:~;:=:::~~::.c~-~=:1::::1:~--r::·:=r:::::::::~~-r~~:=-~==:::L___ :-··. . .f,p.o:4, .. ow\vM .. *QM. ~A .. ~Q p 7-ifOO ELEV~TION 311F' : : : ' .. ~ .. TYPICAL SECTION OHWM NOTE: OLSON, P. ANO E. STOCKDAI.£. 2010. DETERMINING THE ORDINARY HIGH WATER MARK ON SIR£AMS · 1N WASHINGTON STAlE. SECOND REVIEW DRAFT. WASHINGTON STATE DEPARTMENT OF ECOLOGY, SHOREIANOS 7 ENVIRONMENTAi.. ASSISTANCE STREAMBED GRAVEL FOR ALCOVE APPLICATION: ti$ $JP SIEYE SIZE 6 INCHES 4 INCHES 1 1/2 INCH J/4 INCH J/8 INCH NO. 4 NO. 40 NO. 200 PEBCENI PNi51NG BY WFJGHT 70--60 55-70 45-60 30-50 25-35 16-30 15-20 0-5 COBBLES MAY BE INCUJOED IN THE GRAVEL AND A1.L C08BLES LARGER THAN 4 INCHES IN OIAMETER SHALL BE EXCLUDED FROM THE GRADATION TEST. GRAVEL AND COBBLES SHALL BE ROUNDED. HABITAT MITIGATION ALCOVE GRADING STATIONS 2+33 TO 3+04 AND 5+09 TO 5+53 SCAl£: H: 1"=10', V, 1"•10' PROGRAM, LACEY, WA. ECOLOGY PUBLICATION fOB-06-001. . FIELD STAKED BY KING COUNTY ENGINEER Ill, ENVIRONMENTAi.. UNIT MARCH 2011. FIEl.D BOOK: 09006 01-201 APPR0"4D: DON ALTHAUSER P ,E. 912011 SIJIM'lm KING COUHJY 01-2010 -9 1 2011 -DOUG OUN SURVEY BASE ~ COUNIY 02-2010 TREVOR CRAY, PLS 02-2010 -DALE NaSON 9/2011 CH£a<m N -DEsaQf ENTERED: M. RA.DD.LA •'2<>11 NUU. -If'( .. lE ~ King County KCfCZO No. PROJECT No. 9A12D5 o.partrnent of Natural Racourcaa m:I Palb Water and Land RasourteS Division SURVEY No. ---__ ... MAl~CE DMSI N No._ • ChtWJe Troe, Dlr8CfCr CALL 2 WOl'll<INQ DAYS BEFOl'E YOU 0:0 H00-424-5655 (UNDERGROUND UTIU1Y LOCATIONS AR£ N"PROX.) IIIIAY C&& DMll\lAQl: IMPROVEMENT SHEET 15 a1c a a ECn01l!II AM) HABll'AT l\!JIICM'IIO,I! DEl'A!UI OF 10 SHEETS 2008-18 - .,,,-_: '.;...:c ! ··TOI· Elli··················:········· ...•.•.•. , .....•... ·······+········ ......... J ................ . FED IIOOlO SUM'lm TYPICAL SECTION -HABITAT MITIGATION LOG PLACEMENT HABITAT FLOODPLAIN AREA AND ALCOVE STATIONS 2+33 TO 3+04 AND 5+09 TO 5+53 SCAL£: H, 1"=10', v, 1"=10' 09~8 01-201 APPROWD: DON N..-••• -P.E. KING COUNlY 01-2010 -DOUC QflN .......... SU1MY BASE ..,l!ll(G COUNTY 02-2010 1REVOR CRAY, PlS 02-2010 ......... DAU: NElSON -DAU: ND.SO o---DESICN DmR1D: If. RADEllA flf DATE ' I SE[ PlANTllG NOTES ANO PlANLG PIAN SHEErS lm ----t------i , .eLANllNG_WlllOW-STAKES. t ----t------1 -l-.-_. WIUDW srt ·~'---- ; -i-. -. - ! -, I . . , ••••••• .. , ... ,.,,,,,,, .. ,,j••••••••••••••H••••••••••••••••m•••~•O•HHoOHH•>m_,, .. ,,.,,,,,,,m, •••••••••••• .,,mo••••••••••••••••f •H••••••• , .. ,, .. ,,,,,,,,,.,,0,0,mooo,,,o OOOHOOOOOOO,mm,,,,, .. ,,,,,! .. HHOOOm, .. Jl5 Q EROSION CONTROL Ci..DlH ~ . . · · · . EROSIO~ SEDIMENT=-......._-!-_. _,--., ':'~ ~ v_:~ >s: >s, ~/ '-: . ', ~~)>?~.'~ );~ ~-~ _. . -? APPLY EROSION CLOTH TO F1Rsr,"-.R, V::-0::«~ ::< <::<, i -----·, --;, , A/ rs·-o,EXPOSEO,so1L-A1:0NG~ 7'.?i)" A ;),(' :;--(' ---M. -CREEK---i. ' ~ -Y. . .:,_"f-c.J!,QPE.W!O'!VAR\fF roe._ ~ '_ e>~'-)All~~P.i\a .. PEJC"''~"-- , • -· • -• • -.-< »-'. // V/'vl APPLY TO ALL ;t.TIONS ,y/ . 9~~~<· '~~\~~0(~~(~%v>S< (O,tQQ~~~~~~~···BY.(~,·~ '"" ,~~~fr~~:···jfp[jEi) ..... JIO.Q . . Yfth' . -:h' . ! LANOWARO_OE.~OSION....__ ,., x._ ,~., ~<:·( ::of.>,, ,.,:<;\ / ' ; CLOTH, FROM STA. · >..':0...c,-, 0±00-TO.STA../7.+0o __ _ · · ·6: A A «'1o;g_o__ 1· oo 2ojoo 2s oo 30100 / 1 l 1 --, -!----i j,---- 8/2011 9/2011 KCFCZD No. PROJECT No. _ 9A1205 912011 SURVEY No. 9/2011 MAINTENANCE OMSJON No. • TYPICAL SECTION FABRIC APPLICATION SCALE: H: ,. = 2.5'; V: ,. =2.5' ~ King County ~d Nani Recourca lll'ld Parts WatGf and Land Resources DMsion ---Cepftld Sontcas Unit """"'" -- CALL 2 WOl'IKINQ DAYS BEi Ol'1E YOU DCQ ~ (UNDERCROUND unurv I.OCAl10NS ARE APPflOX.) SHEET 16 MAY a K CMINAQE IMPROVEMENT CIIC H I :CJ0.\!11 Na) HAIJl'AT t!lmAllClil D21'A!LS OF 19 SHEETS 2006-161 -- = - = ..., - ;;;;: ;,Ji U' - !:'."l "'"' L:t 3/4" NON-GALVINIZEO CHAIN ANJSH GIWlE PRO'IIDE MANTA RAY MR-1 ANCHOR PER j LOG WITH 5/16" DIA. STAINLESS STEEL CABLE FROM ANCHOR TO CHAIN ATTACHMENT EYE AT EXISTING GRADE. CONNECT WITH LOK-A-LOY 10 CONNECTING LINK OR EQUIVAUENT. SECTION PIN LOGS WITH 5/6" DIAM. REBAR CUT FLUSH TO LOG ·15' MIN. DEP'lH BELOW ANISH GRADE. ACQUIRE 6' EMBEDMENT IN CONSOLIDATED SOIL LAYER. TEST HOLDING CAPACl1Y PER MANTA RAY VENOOR SPECIFICATIONS. # of LOGS 7 5 4 16 total 30 30 60 total 2 78 total LOG TABLE LOG ROOlWAD OR LOG SIZE LENGTH WITHOUT {W/OUT) ALCOVE AREAS 16"-24" dbh 30' rootwoda 1B"-18" dbh 30' rootwods 12·-1a· dbh 30' rootwoda FLOODPLAIN ROUGHNESS 12"-14"dbh 30' w/out 12"-18"dbh 30' roatwada 27"mln snags LOG WITH ANCHORS NlS ffi 13 '---' IV•grodo I % I !I ~~ 11 l: ~;11; SNAG DETAIL NlS FU TOP 1r INCHES WllHSIIIE- """""""'""" INFtU. wnH CRUSHED SURFIGG 8,1,S[ COURSE. TAMP 1l) COMPACT L8::J 13 '---' A-slgnlD- dlll-5/16 .. -.. --- WETLAND PROTECTION SIGNAGE N1S SNAG NOTES: 1. WILDLIFE SNAG TO BE PLACED AS DIRECTED BY ENGINEER OR ECOLOGIST. 2. AU. SNAGS SHAU. BE WESTERN RED CEDAR OR DOUGLAS-AR TREES WITH A SUBSTANTIAL PORTION OF THEIR LIMBS LEFT INTACT. DO NOT TRIM TOPS, AS llAMAG£D OR BROKEN TOPS ARE PREFERRED. PRO'IIDE LOGS WITH NUMEROUS UNTRIMMED LIMBS, WITH A MINIMUM OF 6 LIMBS. LOGS USED FOR SNAGS MAY BE PARTIAU.Y HOU.OW AND CONTAIN CAVITIES AS LONG AS THEY ARE GENERAU.Y SOUND AND INTACT. 3. SNAGS SHALL BE A MINIMUM OF 10 INCHES IN DIAMETER AT BREAST HEIGHT (DBH) WHEN INSTAU.ED AND SHALL BE PLACED INTO THE GROUND TO A DEPTH EQUAL TO 1/3 OF TREE HEIGHT BELOW GROUND. 4. SNAGS WITH SUBSTANTIAi. ROOT MASSES ATTACHED MAY BE PLACED TO THE DEPTH INDICATED AND BACKALLEO WITH QUARRY SPALLS AND SOIL ONLY UPON APPROVAL BY THE ENGINEER. MJD\.ATION PIAN Nro:ES (A) CONSTRUCTION NOTES 1. TREES TO BE PRESERVED WILL BE ~GED IN THE AELD BY THE ECOLOGIST. 2. INSTAU. SILT FENCES WHERE DESIGNATED ON THE PLANS. INSTALL ANY OTHER EROSION AND SEDIMENT CONTROL MEASURES AS REQUESTED BY THE ENGINEER 3. ELEVATIONS SHOWN ARE ANAL GRADE; B INCHES OF 0\/ER-EXCAVATION WILL OCCUR AND BE BACKALLED WITH STREAMBED GRAVELS WHERE INOICATED ON PLANS. 4. EXCAVATION OF ALCOVES ADJACENT TO THE STREAM CHANNEL SHAU. TAKE PLACE ONLY DURING THE ASH WINDOWS AS DESIGNATED IN THE PERMns. WHEN EXCAVATING ADJACENT THE STREAM CHANNEL AN EARTH PWG SHAU. BE LEFT BE1WEEN THE EXISTING STREAM CHANNEL AND THE EXCAVATION AREA PRIOR TO REMOVING THE EARTH PLUG AND CONNECTING THE EXCAVATED CHANNEi.. A TURBIDl1Y CURTAIN SHAU. BE INSTALLED AS SHOWN IN THE DETAILS TO PROTECT THE STREAM FROM SEDIMENT AND TURSIDl1Y DURING CONNECTION. 5. IF ANY GROUNDWATER IS ENCOUNTERED DURING EXCAVATION, DEWATER BY PUMPING AND BROADCASTING TURBID WATER THROUGH PERFORATED PIPE MANIFOLO OR EQUIVAUENT AND DISSIPATED OVER VEGETATED STRIP IN UPLAND AREAS OF THE SITE. IF GROUND BECOMES SATURATED A 8AKER TANK SHALL BE USED. 6. ELEVATIONS ASSOCIATED WITH CONTOURING ALCOVE AND FLOODPIAIN AREAS IS TO BE DIRECTED BY ECOLOGIST IN THE FlEl.D. 7. PARTIAU.Y BURY AND PLACE LOGS IN THE EXCAVATED ALC<:NE, LOG PLACEMENT SHOWN IN THE PLANS ARE SCHEMATIC; ACTUAL PLACEMENT AND ARRANGEMENT TO BE DETERMINED BY THE ECOLOGIST IN THE FIELD. ANCHOR AS SHOWN IN PLAN DETAILS. 8. PILACE 6 INCHES OF STREAMBED GRAVELS Wl1HIN THE ALCOVE AREA, PER TYPICAL SECTlON, SHEET 15. 9. PLANT EMERGENTS ANO SHRUBS IN ALCOVES ACCORDING TO PLANTING PLAN. 10. REMOVE TEMPORARY STABILIZED CONSTRUCTION ENTRANCES AND REMOVE HIGH-VISJBIUTY FENCES, AND ANY OTHER EROSION CONTROL MEASURES STILL INSTALUED AT THE SITE. 11. CONTRACTOR SHALL PRO'IIDE STREAM ISOLATION / TURSIDl1Y CURTAIN PER WASHINGTON DEPARTMENT OF ECOLOGY STANOAROS. (A) PLANTING NOTES 1. MmGATION PLANTING PLANS REPRESENT A CONCEPTUAL PLANT LAYOUT. AU. MmGATION PLANTING PREPARATION WILL BE DIRECTED IN THE AELD BY THE ECOLOGIST. 2. PLANTING SHAU. TAKE PLACE DURING THE DORMANT SEASON (NOVEMBER 1ST THROUGH FEBRUARY 281H). PLANTING MAY BE AU.OWED AT OTHER TIMES AFTER REVIEW AND WRITTEN Ai'l>RovAL BY THE ECOLOGIST. 3. APPLY JUTE EROSION CONTROL FABRIC AS DIRECTED BY ECOLOGIST WITHIN THE FLOODPIAIN EXCAVATION AREAS AND ALL PLANTING AREAS WHERE REED CANARY GRASS HAS BEEN COMPI.El[l.Y REMOVED. 4. IN ALL PLANTING AREAS WHERE REED CANARY GRASS IS PRESENT, FIRST MOW THE GRASS. CO\IER MOWED REED CANARY GRASS WITH PROPEX 8418 (OR A SIMILAR BARRIER MATERIAi. AS APPROVED BY THE ECOLOGIST) AS NEEDED ANO DIRECTED BY ECOLOGIST. AND STAKE IN PLACE USING LIVE STAKES. 5. PLANT STAKES AND TREES AS DIRECTED BY THE ECOLOGIST THROUGH THE_ PROPEX (OR EQUIVAl.£Nl). 6. AU. PLANTS SHAU. BE NURSERY GROWN A MINIMUM OF ONE YEAR. PLANT MATERIAL IS TO BE SUPPLIED BY COMMERCIAL NURSERIES THAT SPECIALIZE IN PLANTS NATIVE TO THE PACIFIC NORTHWEST. PLANT MATERIAL SUBST1TU110NS ARE SUBJECT TO APPROVAL BY THE ECOLOGIST. 7. NO TACKIAER, HERBICIDE. OR FERTILIZER SHAU. BE USED IN THE PLANTING AREAS. (A) GENERAL NOTES 1. TO PREVENT REESTABLISHMENT OF INVASIVE VEGETATION, THE TOP 24 INCHES OF EXCAVATED SOIL IS NOT TO BE REUSED AS ALL ANYWHERE ON THE PROJECT SITE. (D) KING COUNTY WETLAND/STREAM PROTECTION SIGN INSTALLATION NOTES: THE WETLAND/STREAM PROTECTION SIGNS SHAU. BE POSTED ON THE BOUNDARY OF THE MITIGATION AREA AND/OR THE CONSERVATION EASEMENT. ONE SIGN SHAU. BE POSTED FOR EVERY 150-FEET OF THE BOUNDARY OF THE MmGATION AR~ AND/OR THE CONSERVATION EASEMENT IN A PROMINENT LOCATION. SIGNS MAY ALSO BE ATTACHED TO NEW AND EXISTING FARM FENCE5. • SIGNS ARE AVAILABLE FOR $9.22 FROM: KING COUNTY DEPARTMENT OF DEVELOPMENT AND ENVIRONMENTAL SERVICES 900 OAKSOALE AVENUE SOUTHWEST RENTON, WA 98055-1219 · CALI. 2 WOll<INQ DAYS BEFOl'IE YOU IXQ ~ (UNDERGROUND UTlUTY LOCATIONS AR[ APPROX.) FIElD""""' 09056101 20101 I e;51~:t;+ ,-DON AlllWJStll P.E. 912011 = .... ..:::: ~~-~~:w 1o·t-JrdE$M==-OOIJGCHU< 9/2011 KCFCZONo. ~KingCounty MAYCF (~IMPROVEMENT SHEET • PROJECT No. 9A1205 _ .. ......,_...,_ 17 DBICNED: ~ NELSON 812011 SURVEY N Water and land Resoun:es DMsion OF ---"DAl£"""-""El"'59'f!!!ll!.IP2!!ci-20!!!J.!!]Ot--l~f--1-' .!.'=-__,-J .. 1,!;!l1'-e::IUX::::lf-=::r:-1· =:::)1 •. ---j ..i:' L [j.J ..,. ....., """""' "-RADEUA 912011 ~~~~ 4 ==-...: HABll'AT ll!JIIQATlc:II ~ SH~ETS ---ll!SfALLATlc:II Dl:rA!LB N(JJ t(OIEB 200a-18 ---------- I I I May Creek Riparian Buffer Planting-r .... iii --~~ ... Seasonally Saturated Areas, ...... w "' Stations 0+00 to 7+00, 13+50 to 19+00 .. .. .... .... .... .... .... .. ~ May Creek Alcoves PlanUng Plan • c:J LaUn Name Common Name Slze/Spoclflcatlons Quantity west of 148th Avenue SE Tniea Latin Name Common Name Size/Specifications Quantity ,f/1$111,uhm Rohldtt 6-8' ikighl 10, Emergents -for alcoves near stream Plant9' DC. Sd'1'fU aC2lftlJ """""""'""""' Plug(PWd 12"0.C.) soo I 5 sal., 5-6' Hcighl FuU Dense Foliaae Elrocharls pa/ialris Common spiluHush Plug(Pllnt 12"0.C) soo Pkm 1itclleruls Sitka 1pruce Plant 9' OC 10, Cal'Cl"stipnta S:iwbeu udgc Plq(Plant 12"0.C) 500 •. Sb rubs/WIiiows Popuhu btllsami{ff'rl 1f'P, Black cottonwood 6' SUlltc. lopan, 1• dianldcr ,., ... ,.,,.,,.. P1mit 9' o.c. C01711D' ffna!II Rcd-oiser dogwood Bare root. mi. 12" long "' I 5 gal .. 5-6' Height Full Dense foliage Plantl'O.C Tliujn plk/Dta Wc:nem ml CCGlr 10, Pfnnt9'0C.- Pit,~ ct1pbarvs Patine nind,;at; Bare 1'JOl, mi 12• long ISO Shrubs/WIDOWS Pl&nll'O.C. Uvc Stakes,)' Loiig. 1a·.1" Dimnctcr RosapisocruptJ Pea l'i'uhcd rose Bare roo1, mi. 12" long 250 Camiuserkm RClkiiser dogwood 1100 Pbntl'O.C. Pbn!J'OC I I Rulnu sper:t11bllfs Salmonlk:ny Bareroot.mi.12"'10fll ,so S.li.t lt1tiamlm Pacificwmow Uvc Stu.es, 6' Long. 112.r Dimncter 1100 Plzntl"O.C Phmtl'OC. liveSbks S-lix litdloasisc Sitka willow Minimum 6' Long Y4-1" 300 &,/fr shchnuU Si1b\Villow Live Stakes. 6' Long. 112-1" Oillffldcr 1100 --Plant]' OC Plan!J'O.C Live stakes Salix lralalldm Pacific willow MinimUIII 6' long 300 Minimmn JW-1" diamaa I Plan1J'O.C May Creek Riparian Buffer PlanUngT, o ~ -;,~~ ~· Live pole aming Popv/UJ tricluKarpa Black Cononwaod Minimum 6' long 2SO Permanently Saturated Areas, ~ ~ o ~ ~ 0 o .~ o Minimum J/4"-I" diainet.cr Stations 7+00 to 13+50, 19+00 to 29+00 PbmJ'OC. ......... ·--·-Q""""' I I TREES Fraxin,a lmifo/ill "'-""' S'-6' height .,, Plam. 9'0.C May Creek Wetland Enhancement Planting * I' SHR\JBS Live SW.cs J' long, 11i--I" Plan -west of 148th Ave SE COl'lff<llericta Rcd-oiser dopood """""· 1,700 Plant J' O.C. ,.1A1N:~ Live Stakes. 6' l..an&, 112-r 1JO,UO ..-,. INt (S K,-J Salix /tl$iatldra Paciric willow """"" 1,700 ......... ............. ._ ....... -Plant J' O.C. I Live Stakes, 6' Lon1, 112-r Ptl/flllUJ tridt«tupa Black Couom.ood 6' de. lop on, I " diamda 7,000 Sali.r litchensu Sitbwillow DiamClcr 1,700 Plant'.1'0.C Plm!J'O.C. I Bare root, Minimum 12" Cormus~ Rtd-oiser dogwood """ 300 Plzml'O.C. Salix lasialldra Paci(ac willow Uve Stakes, 6' Long, 1/2-1" """""' ,.ooo I Planl.J'O.C Salis lilcle,uis Sub w:tllow Live Stakes, 6' Lons, 112-1" 3.000 I Diameter PbmJ'O.C 'PLANTS WILL BE INSTAll£0 THROUGH PROPEX (OR EQUIVAlENT). SEE NOTES ON SHEET 16. I I CALL 2 WOOl<lNQ DAYS I BEFalE YOU CXQ HI00-424-5555 (UNDERCROUND umJTY LOCATIONS ARE APPROX. . I I 9"'011 rE APPRCMD: DON ALTHAUSER P.E. ~ King County MAY ChEUC. c»WNAQE IMPROVEMENT SHEET FlElJ) """"' 09056 01 2010 . • 18 KINC COUNTY 01 2010 PRO.ECT KCFCZD No. SUR'IEl'8> DOUG CHIN 912011 • • -9A1205 Department of Natural RIIIIOl.lrms end Pariil Of SUR'l'EY WE ~NG COUNTY 02-2010 ~ PROJECT No. Water and I.Md Resot.-ces OMslon 1REYDR CRAY, PLS DALE NELSON 9/2011 SURVEY No. ---10 02 2010 """"""" ----n.1.1 c-N~-o,_ .. n .. o .. . ~ ·-.. f'I..ANTI?(Q TABI.EII SHEETS -, DESIGN £N1ER£1I: M. RADEU.A 9l"ln11 !IAJNTENANCE 4 """""'--NUii.i ....,..,. Elf -DMSION No. 2006-16 ... - • -- n ... - ~ _/ S'i i;.( u '.t"l \-;:} "''' " II \ I ~I If) q ~ er ~~1 ~ _____Ilg_ SCALE IN FED ;J] I wfii'Njp------, ,ENHANCEMEII!/-._ 'fLANTING 1 - ,.----Y -.I. WEST OF 148TH AVE SE MITIGATION PLANTING SCALE, H: 1" = 60' FID.D BOOK: 090515 01-20101 SURIIE'tm: KINC COUNTY 01-2010 SUIM'f 1MSE ~G COUNTY 02-2010, lREVOR CRAY. PLS 02-2010 -NELSON 0::1'-· ---f1f I _i;wt I ~I II I! APPRCMD: DON AL'TliAU: PRO.ECT MANAGER: DOUG CHIN DESIDHfD: DAL£ NELSON DESCiN EN1ERED: M. RADELL\ . ' P.E. .. ,,. """" IN rn:, 9 2011 ~/2011 kCFCZD No. PROJECT No. - 8/2011 SURVEY No. 9 2011 MAll'!TENANCE OMSION No. ~ .,~--¢t.......--- DA1205 • ' \k \k ~~" ~""'I<-" \ "'-.I<-~ ~ King County Department of Nallmd R8ICIUr'olN end Parka Water and Land Resources DMsion ---Copllnl 8orvlccD Unit --- ' • ~~. +\ "'> ~~ .\ • I . {~ \ \ ~ \\~ \~ ' ...... ', ',, ' ' ' ' ' ' ', ' ' ' ' ' MAY a+ K DAAJNAQE IMPROVEMENT PI.ANIOOll Pl.AN \ ' \ \ SHEET 10 OF 10 SHEETS 2008-18 ~.c~ = -1,l!I "-~ ,~.u """' ~--,_J ¥.'j >'---' ,~-i '.Cl FlEI..D BOOK: SURI/E'l"ED: VIONITY MAP SEC. 22, TWN.25N, R. 5 E, W.M. OOrlll!W©&®ulblli I I I I I I -""' I <t,'t-. ' ~ /''' p"'' : G~'i, / ~ ' CO'U(Ja.r Mountain Regianal Jrildlan.d Pa.rlc SE MAY VALLEY RD ~~~,),/ C, /' \i o-f-•• A ·= ' NE 28TH ST OO~OOu@lril NE 24TH CT .......... SHEET G1 C1 C2 C3 SWPP1 SWPP2 L1 L2 2010-2 Goulet,Radella 1!i , II : ,J' I --------'----------' ~~~ NE 24TH ST ,---. I I I w I ~ I w I ,l : ~ I ,. I INDEX DESCRIPTION w z ~ ~ z VICINITY MAP AND SHEET INDEX § \ ·,., EXISTING CONDITIONS PLAN, CHANNEL PROFILE, LEGEND AND ABBREVIATIONS '\ \ GRADING PLAN AND PROFILE -LONG MARSH CREEK AND MAY CREEK SIDE CHANNEL CROSS SECTIONS AND LOG DETAILS TEMPORARY EROSION AND SEDIMENT CONTROL PLAN AND NOTES TEMPORARY EROSION AND SEDIMENT CONTROL DETAILS PLANTING PLAN AND NOTES PLANTING SCHEDULE AND DETAILS APPRO'v£0: Don Althauser, P.E. PRO..CCT MANA.GER: Doun Chin !7-2011 7 2011 SURYEY BA.SE r.lAP: Radella 9-201 8-2010 9-2010 DESIGNED: WES KAMEDA, P.E. 7-2011 l PROJECT No. CHECKED: Dale Nelson 9-2010 Julia Turne" LG. 7 2011 BY I , DESIGN ENTERED: l. TRAXINGER 7 2011 J MAINTENANCE DATE --. DIVISION No. NUM. 1C12D5 4 tQ Kong Co11.11ntty Department of Natural Resources and Parks Water and Land Resources Division Stormwater Services Section Capital Services Unit Christie True, Director Department of Natural Resources and Parks LONG MARSH CREEK RESTORA TiON CONFLUENCE TO RIVER MILE 0.05 ~ King County Department of Natural Resources end Parks Water arid Land Resources Division Stormwater $0fVices Sectial, Cllpltal Servlc:es UnH Christif/1 True, Dir8ctor LONG MARSH CREEK RESTORATION CONR.UENCE TO RM 0.05 VICINITY MAP /WD SHEET INDEX SHEET G1 OF 8 SHEETS 2006-42 I I I I I I I I I I I I I I I I I I I / _,/ d ,,, ,- / -.;/ \ . \ -:'!\~ ,i,1 BARN ~ ~ ~ " N" \ I ~ I , ~ec.\w i u!rt-R ) / / / / //d¢,-.,,-.. / o~"" / --- .~·"= ' ...-\ / #'-/ \ / (:,0 / \. / ,<~ / / -f's' / ' / s / ~~· ------\ ------\ / GENERAL LEGEND: ___ '¥___ EXISTING WETLAND BOUNDARY · --· · · -EXISTING STREAM/CREEK --x--x--x-EXISTING WIRE FENCE CJ c:::=i CJ EXISTING 165' STREAMM BUFFER \ HOUSE ; ~"r~ ri I ~1 -I / 0 0 DD O O ODD DO EXISTING 42"• STORM DRAIN CULVERT I \ ( \ \ ABBREVIATIONS: I \ HARO~~ GAMBINI, JR \ 15019 5£. MAY VALLEY RD \.,.....,......,.,,..@ SWPP STORM WATER POLLUllON PREVENTION PLANS HPA HYDRAULIC PROJECT APPROVAL I TESC TEMPORARY EROSION AND SEDIMENT CONTROL -~ / I/ ~ ~ r I"" ,, /; /i 4-,. ,,.,,,, . I _,/ .• )c I I I I / / -~. :+ /_,/io / .... ;, / I :-9-#'.,/ / -/ \ +/ ./ / ,. / .--x--X\_,.,,.-"1- PADDOCKS PASTURE ';:. "' r / r, \ \ -'/ \ /;/ ! ,(I \\ --- ,/ \ ------.·- .,, ~,' ~ '" ""' I \ii, ~ ~ L f ~ :.I. i i WHITNEY &:: JEFFREY WALKER 15125 S.E. MAY VALLEY RD ----1 @ I \ \ \ \ ... - STREAM BUFFER LONG MARSH CREEK ,,c::::>' '~'"='"=':;=,:;=, / '\ .,.....,,.,......... \ \ \ 325 . 1 1 I I I 1 ! ' I ·1 I I I 1· : I I 1_ +---,-----+·----l---J1 I I ! I ' I I I I ' I '6'"t/o ~ -i ' II I I ' ; ' . .J. ____ J : J__ ' I==·-:::: I I 1.J.:~ 1' ' ' I I , I ' I I , ; .. -, --I ·---·, . c:,<-e:==·c:: ..... , \ ... --V.2lL --I r-EXISTING MAYi CREEK CENTERLINE I i i II I : I ! i ;:==1=:;==~=~::::::::".--:--------I METAL 0-2 17% 1: \ ti.e-1----.-.~-------I, ·-=,c_::___J•-___ L__ 325 32o __ .... •/~ AT ,CONFLUENCE WITH LONG MAR~H CREEK ' I I I I i : : i /106.66 ~.F 42 •• 9oR~~-~~~---·:::}:::::::::~ -§_. :"'-II ' j I ' I : ' I I i '"' L--1-,-.,,; --C' ""!--+'1""""'\"'"'" ' ,__ ,-, : i ' ' i I "' 315 /_ . I . i ! i :4DJ'--;---1--: --I: i i ...... ' ..... I ... I I l ! 1 1 1 ! i l \ I -I 1. j----=-~·-·.Qc.9~% --· -..,-I , j , I I I i I I ' I ' I II I II JO 0 JO !9. SCALE IN FEET CONTOUR INTERVAL = 2 FT. CALL 2 WORKING DAYS BEFORE YOU DICl 1-800-424-5555 ., 310 ~=L.3 _ 5 ~·; -__ J : i I i . i lXISTro~ L~toGw Mt:it?rEK i--;--· n· ; : I ___ J. -· i . 315 0+00 , 1---_J... ·· ~~~~---, . -----1------·-·+---··-i-·-····;~oo -1 ··---~~}E:_=:20'~<lRIZ"-".'c.;°_VERT, ··;-bo----i-~ ~------.I---·-;~o~-_ ... ! ... __I _____ ... J .. _ ·······-_ + __ J ___ 310 5+00 {UNDERGROUND UTILITY LOCATIONS ARE N'PROX.) FIELD BOOK; SURVEYED: 2010-2 Goutet.!.Rodello SURVEY BASE liW>: Rodello CHECKED: Dole Nelson 9-201 B-2010 9-2010 9-2010 MUI.I. :E.VISION BY DAn: APPRO'.m: Don Althauser, P.E. PRo.ECT MAN~GER: Doug Chin DESIGNED: WES KAMEDA. P .E. Julia Tumey LG. 7-2011 7-2011 I PROJECT No. 7-2011 7-2011 ,. _ .,.,11 ] MAINTENANCE DIVISION No. DESIGN ENTERED: :Lc.!!TRAX,oo,elN,eG,:cER,_ ____ _jZ.~s!J_J . I' " I 1C1205 4 fW King County Department of Natural Resources and Parks Water and Land Resources Division ---Capital Services Unit Christie True, Dintctor LONG MARSH CREEK RESTORATION CONR..UENCE TO RM. 0.05 EXIS11NCI CONOmONS Pl.AN, OiANN8.. PRORLE LECl9!D AND ABBREYIATIONS SHEET Cl OF 8 SHEETS 2006-42 I I I I I I I I I I I I I I I I I I I ~ 'k • 0 I ~ ,, :0 f I ~ I ' I l I l > '/ i I~ f -u ,, 0 -u '" ,, . :/ C I I \ SEC. 22, TWN.~5N, R. 5 E, l(V.M, ' I -.,_.----.-y: 1-'- ' I \ I I I I t / I I / / r -/ \ CONSTRUCTION SEQUENCE, I \ 1.HDLD PRE-CONSTRUCTION MEETING AND NOTIFY PERMIT AUTHORITIES OF THE PROJECT f \ sTART DATE. / HAROLD GAMBINI \R 2.KING COUNlY ENGINEER OR ECOLOGIST WILL FLAG THE CLEARING AND GRADING LIMITS ' J.S SHOW ON THE PLANS. 15D19 S E MA y VALL y RD 3. TREES TO BE PRESERVED SHALL BE FLAGGED BY THE KING COUNTY ECOLOGIST. I '9091' \ 4.INSTALL SILT FENCES WHERE DESIGNATED ON THE PLANS. IMPLEMENT THE TESC . 11 ~ PLAN. PREVENT SEDIMENT FROM ENTERING THE WATER AT ALL TIMES. INSTALL I I \ ADDmONAL TESC MEASURES TO SUIT THE CONDmONS AT THE TIME OF CONSTRUCTION I AND AS REQUESTED BY THE KING COUNTY ENGINEER OR ECOLOGIST . / WINDOW /"5 DESIGNATED IN THE HPA. / 5.BYPASS LONG MARSH CREEK FLOWS PER THE TESC PLAN. 1 1 \ --6.EXCAVATION WITHIN THE STREAM CHANNEL SHALL TAKE PLACE ONLY DURING THE FISH ---\-('--\ 7 .FINAL GRADE/STREAM CHANNEL ELEVATIONS ARE SHOWN ON THE PLAN. \ ---OVEREXCAVATION OF ROUGHLY 6 INCHES AND BACKFILLING WITH STREAMBED GRAVELS -_j,. ---\ \ I IS REQUIRED WITHIN THE LONG MARSH LOW FLOW CHANNEL AND THE MAY CREEK SIDE f \ \ CHANNEL. EXISTING ONSITE STREAMBED GRAVEL MAY BE REUSED. a\ ROVltlE RIP~-~ROTEqlON ,\T ·ULVERT qtJTLET. 8 ·:~E~~v:~~s~~ ~E~~~LN~~ :6 ::E~X~A~ :L~?L/~~:J LEFT I '\ [ k ' I~ t \iiS ' \ X~ 1,, 31 31 IPRAP~ PAD SH"1-L-EXTE~ 141._ FT. DOWNSTREAM ....-:: -SHALL BE DEPLOYED PRIOR TO REMOVAL OF THE EARTH PLUG PER TESC NOTE NO. OF THE\CULVERT\ND BE \10 Ff. DE BY TWO \ '\. 7 SHEET SWPP1. .~ X I ' D?:. D · J \ "\ 9.CHANNEL/BENCH WIDTHS AND LARGE WOOD PLACEMENT ARE TO BE ADJUSTED IN THE --1 s. FJELD BY THE KING COUNTY ENGINEER OR ECOLOGIST. ~ --.. ,Y( 1 0 OVEREXCAVATE AND EMBED AT LEAST HALF OF THE LENGTH OF THE LARGE WOOD \ I L \ -/ PIECES UNDER BACKFILL AND BOULDERS. / ,I..-\ 11. PLANT EMERGENTS AND SHRUBS ACCORDING TO THE PLANTING PLAN. ;J.,,,, 12. REMOVE THE TESC MEASURES AND FLAGGING. -'\i-'-~~~~E AND/OR RESEED ANY AREAS THAT WERE DISTRUBED BY THE CONSTRUCTION. ~ -~----~--\4~..J;;;CJ.... -..f!;;,:.~_-="5~::::::: ~~~v---T----7-·rw--:~~~ , ~--,--\ \ /7'~1 / ~ ~ <. / ---~...i;'il,----'1'.c\'-OG AND BOULDER DETAIL L1.J 1 ~ _ b.J•'Y-I \ ~3 __ ,7 -.._.. Y._/--=-1-fij'J-~ NOTES: t\ ~~ \ ~O ~-~ -, 1. FOR CL~RITY, NOT L NEW /, · ~ • LARGE /HOOD IS SHO ON l PLAN /JIEW. / \ GRADING LIMITS TREES ARE NOT SH ON.--.?~ . (PROJECT UMITS) \ PLAN EW. #' I NsTALL NEW FENCE / t \WHITNEY & J \ALONG CLEARING AND GRADING . J/ \ ~ 5l 25 s E MA y VALLEY RD r[TS AS NEEDED / /A "\4 / \ ~ I . 330 1 ·1 I ' j ' ' i i ; ! ! : i ' - t EXISTi~-G--~ ___ , __ -~~~~~~J~M;;;st:iui~-~u€0i L--,c;::,:;·;;,:::::i:;~::i~~~A~;~;~;;:~~~'.~;(\1r- GROUND ~CHORING !AND EMBEDMENT : / 1os.B6 LF. 42"Ci c~RR ! ! I -----------: -=t--=-I -J-::::.:-=-:·-·::::::::::::,. _:::::_-7~----: ---f---------( _______ c,;':_~;;:::::::::;:.::·:·~~:::-· 1 ---; '-i-! i 31973 I ----I I I i CHANNEL A -·--··t---··--··-i--~-~-----+-----~ . I . ·-·--+------~----·-----,······---· --·-~--···-·-·-1Nl!£LALCUTVERT _______ ;. .. --·-··---...!-------+---·----· I ! ,,_ I 0.5' STREAMBED . I ' '~ i GRAVEL i 1 -320 I . , IPRAP PROTEC~ON I . : . --r·----·-t---. ·-_.,_.__ . ----·-·----C-·-------+-· --. ----~·---"--- : ! -310 I ; I I ; STA.I EQUATION ! LONG MARSH Low FLOW! CHANNEL: STA. MAYi CREEK SIDE CHNL STA 0+42.07 --I ----1 ·.-·"···-' . ·-······l o+oo (EL 309'.oo)= ! l i--~---t--+-----·-1 . ' ~ ___ I __ _J__ + ta Ill II ,0 0 SCA!£ IN FEET CONTOUR INTERVAL = 2 FT. I Side Channel MayCRK PROFILE I " Station 321---r--=1==-~---,---- LLJ EXISTING ' : , 320 GRADE 1 1 ,,..,....-:::..:-1 ,--~~-~-J I I : liJ: DESIGN : "'; --1- ----. ' ,GRADE, '- ,.3&i ·---M'-----l~-1.63% 1 _~ 31 31 I / -310 i 0.5' STREAMBED /GRAVEL l 3051 'I : , 11305 o+oo 1+00 EQUATIO~ STA. 0+42.07- STA. 0+00 LONG MARSH CREEK EL.-309.00 ~ r-~ ~ Wt J ___ _;_ __ ___j_ ___ ~ __ .,.; ___ --!----1----...;...---l------i-----::--l:::----~----+------i-----l----:;-;l;;;;---+----.;.....----+---+--:;;:t;3oo in 3+90 2+00 3+00 1+·00 CALL 2 WORKING DAYS BEFORE YOU DIG 1-800-424-5555 {UtC'.lfltClROU UTIJlY LOCA.llONS AAE .t.PffiOX.) F1ELD BOOK: SURI/EYED: 2010-2 Goulet~Rodello SURVEY BASE MAP: Rodello CHECKED: Dole Nelson 9-20101 B-2D10 9-2010 9-2010 NUM. EVISION BY ""' APPROVED: Don Althauser, P.E. ~~ii1: Doug Chin DESIGNED: WES l<AMEDA, P.E. Julio Tumey LG. 7-2011 7-2011 ---1 PROJECT No. 7-2011 7-2011 '7_?n11 I MAINTENANCE DIVISION No. DESIGN ENlERED: ,cL.c.!.!TRAX""'-l"'N"GEe,R<_ ___ ~I?.:· :;.~,:!.!_JI 1C1205 4 ~ King County · Department of Natural Resources and Parks Water and land Resources Division Stormwater Services Section C.pltlll Servicn Unit Christie True, Di'9Cfor LONG MARSH CREEK RESTORATION CONR.UENCE TO RM. 0.05 SHEET C2 OF 8 ClRAlllNCl PLAN AND PRORL..E I SHEETS LONQ MARSH alEBC-MAY alEBC SIDE OiANNl3.. 2006-42 I I I I I I I I I I I I I I I I I I I LOG & BOULDER NOTES: 1. USE LOGS WITH ROOT WAD ATTACHED. 2. LOGS MUST BE BETWEEN 18-INCHES TO 30-INCHES JN DIAMffiR AND BETWEEN 12-FEET TO 20-FEET IN LENGTH. s,REAM BAN~ .:...---···-··· -··---·-· --··-- 3. LOGS SHAU. BE WESTERN RED CEDAR OR DOUGLAS FIR. f-t--~-s;;f,-;::<;Jlt;.e::--~---j,,.---+---ir---t---t----::+-:--+-----t---1----i--:--t-='\~;f"---,----i----l---t--l 4. BOULDERS SHAU BE GLACIALLY WORN AND ROUNDED 3P' AND 28-INCHES TO 38-INCHES IN DIAMCTER. AV RAGE DIS ANGE BETWEEN EXI TING FEN ES 5. LOGS Will BE EXCAVATED OR INCORPORATED 1NTO THE SURROUNDING BANK CONTOURING OR TERRACES WITH A f.-+--+f.---:'.l~,_'.\:,rijh,[.__;4 ___ -t----jf-----t----t----+---+-----f---+---j-__::,,_,f'F'\c-''ft-;,~~~:::::_+1-+~~;.;;;f;-;:;;;~;;t~;::;;--j MIN. OF 18" S01L COVER. EXISTI~ AND N PER BOULDERS WILL BE USEO 10 AID IN ANCHORING LOGS I NOTE 9N SHEET 103 AND TO INCREASE HABITAT COMPLEXITY. (BOTH 1SIDES) .........=:::s-FLOW C. ~"~ --u·:· ~ cu ~6. ~7. THE EXACT PLACEMENT OF LOGS AND BOULDERS IS TO I J DECIDUOUS TREE BE DIRECTED BY THE ENGINEER IN THE FlELD. ,nn_ero, V ,, h '\I I ., rf' " '"., ---I I iEXISTING ~ASTURE I I I V ANCHOR AND DEFLECTOR BOULDERS 28" -36" {3 MAN) LPG AND BOULDER PLACEMENT DETAIL ffi " NTS 18" MINIMUM SOIL COVER C2 ....__... A MINIMUM OF 1 /2 OF LOG SHALL BE BURIED ALONG LENGTH WITH STREAMBED GRAVEL AND SOIL LOG IS 20' LONG AND 18" -30" DIAMETER. STABILIZE WITH 28" TO 36" BOULDERS ON TOP OF LOG, ALONG AT LEAST 1 /2 LENGTH OR ALTERNATIVE ANCHOR EQUIVALENT. .o .. ·.·S· ~ ------------------------ STREAMBED GRAVEL STREAMBED GRAVEL 1 1/2 INCHES 45-60 --Ti / I -11'---t-="",ti+--z':': [ \ NOTE: , . I 1. VEGEfATION PLACEMENT SHOWN 4 ' I IS SCHEMATIC ~OR THIS ~ECTION ' • ' c;-]'[j\ ( bvEREXCA ATE AND {'LACE 6" ~IN. od WITH Ro TWAD 2 THE GRADIENT W1LL BE ADJUSTED ·1 ! DEPTH S 'EAMBED GRAVE REl.JSE ! . IN THE FIELD a,&.$ED ON LWD i I EXISTING EAMBED GRAVEL WHERE SIZE IANIU'_L.AC~MEN1. I l POSSIBLE. I I ' ' I I I I I I I I I I I 18.00 16.00 14.00 12.00 10.00 8.00 6.00 0 , I SCALE IN FEET 4.00 2.00 'i. 2.00 4.00 LONG MARSH CREEK TYPICAL CHANNEL SECTION NTS 6.00 8.00 ffi C2 ....__... 10.00 12.00 14.00 16.00 18.00 20.00 WEIGHT I US STD. SIEVE SIZE PERCENT PASSING BY 3/4 INCHES 30-50 18 INCHES 95-100 3/8 INCHES 25-35 12 INCHES 90-95 NO. 4 16-30 9 INCHES 80-90 NO. 40 15-20 6 INCHES 70-80 NO. 200 0-5 EMERGENTS~ 4 INCHES 55-70 18 INCHES 18 INCHES · .. ·.·.~.~ . . . ~\·' LOG AND BOULDER PLACEMENT SECTION CD NTS C3 ....__... / / -----,---~~ - r ttt:.J.c .. · :'-".:='"".,.,,""'"' ~~···· .. ·.· .. ·.·.··1 . . .... \" -~.· .·· fl"'zi.:..; .. ''.'.i.......--,.~--.-;.£1 --' --{=~~~~-== ____ J_ ----'-' FIELD BOOK: 2010-2 9 20101 -. SURI/EYED: Gou(et.Rodello 8 2010 ' ,7 I \..I• SURVEY BASE WJ>: Rodello 9 2010 CHECKED: Dole Nelson 9-2010 ~ NUM. -z-:zu =oN ' " --- -~ MAY CRE~K MAIN CHANNE / / / _.,. -EL=308 v/ '? / / OVEREXCAv'~TE AND PLACE 5• DEPTH STR,AMBEO GRAVEL ~ ~IN._/ APPR0-.£0: Don Althouser, P.E. PRo..ECT 7-2011 • ,.., r -, 1""JTTT MANAGER: Doug Chin 7 2011 I PROJECT No. DESIGNED: WES KAMEDA. P.E. 7-2011 - Juli.o Tur~y LG. '}tit 7-2011 .,_..,"11 I MAINTENANCE DMStON No. BY I DATE DESIGN ENTERED· ~Lc..cTRAX=,clNe,G,eERe_ ____ .jI:::e!,l.!_J . I' ·~ I 1C1205 4 =----· -_cL~314~ ~ - I I '-1.0G WITH RbOTWAD !AAY CREEK SIQE CHANNEL SECWION /8'\ NTS C2 ....__... ~ King County Deparaneot of NabJral Resources and Parks Water and land Resources Division Stonnwater Services Section capital Selvices Unit Christie Troe, Dinff;tDr C*1J-2 WORKING l)AYS BEFORE YOU DIG 1-800-424-55! (UNOERGROUNO UllUTY LOCATIONS ARE APPROX.) LONG MARSH CRE8< RESTORATION CONR..UENCE TO RM. 0.05 SHEET C3 OF 8 alOSS SECl10NS AND LOQ DETAILS I SHEETS L.ONQ MARSH aeK-MAY aEB< S!DE QiANNEI.. 2006-42 I I I I I I I I I I I I I I I I I I I J.t ,,,r;;Y l / ' I ,-;/ fl: ( ~ ~ \\ ! I \ \ J \ \Ji\\i\ \ l \\1 \ \ \ 1\ \ \\ /' \t. t I /1\ f 11 kl l ' ' ! ·p\ ,[//\ / I // I ' I \ Fla.D BOOK: 2010-2 SURVEY£0: Goulet,Rodella SURVEY BASE MAP: Radella CHEC!<ED: Dale Nelson ~\\! 9-20101 B 2010 9-2010 9-2010 I ll I l il- l MUM. ""- 'EVISION _ ___.--·- ~ iu I SEO, 22, TWN.25N, R. 5 E, W.M. ' I ffi , I S1\PP2 SILT FENCE~,?, \ \ ......... / __ .,. \ __ , __ , __ \ -- "',_-Y.---)( \ ' ~ \ ----"\ \ -<\ RESTORE CONSTRUCTION STAGING AREA TO ORIGINAL CONDITION \.L i ----\ \ "'U --i "1 C -\ _..-~ \ I \ ' '" I I \ ' --"" ;:: ,U --\ \.--y. VI I I I I ~ ~ {\ I \ \ STAGING AREA £~ BARN / / \ 9121.23 S.F.=0.21 ACRES'/ / '" -\. I I \\ / '"--/ I I , "n \ l JI ~ , , ; ·:_ \ \\ / ,,... \)~\~ / ---...... : .. y. -~ . \\ / / \)\~, / / \ _.,. \ ,,,,,,,.:,.\'t,,';,.G,..-\ _ _.--c-"-~, r.. \ M uff£.R LONG MA~H CREEK , ~ '-i-\5 , , ' \ _-p· 51REA --, , • = __,,.,= =,,, . _j_ --,., ,_.. I a , ,,,.__.. -\ = ' ',,----{' -l \ I I ; ,,,.,, ---\ '\\ r I;} \ \ \ \ I \ \ _ --I I . /I \ HOUSE I V \ /, / I \ (- ~ ~ ~ ;J.. ~ ~ , \ 'I ,' I m \ \ ' 1--,--'1 I ir I ' / ~ I I \ ) --~ ~ .-' \ I ':'.) \ HAROL~ GAMBINI, JR =i .--~ I I I ~ I l_1§Jl1,;-rt, MAY VALLEY RD ... r- CHANNEL .---"" -REALIGNMENT ' I! _,.,.---{:LEARING AND ,, GRADING LIMITS -\-\---tJ.-1 @ ---\g,1 I \ :;: \ ) STA \E rri \ EMPORARY BYPASS-4 PUMP AND COFFER """P2 , ~ PADDOCKS\\ J1a ~ -~ ,- DAM ·'--'t-,.' I EXIST, ;1-8"\0 tul VERT ;,;-.... ___ x_ -e~r" ~ - '$'77 =---,,.,.,,,., =>~'\\ \ ·· 7f 9 = ~\ ~-1l "' "' --- ~ :;: \ ~ \ "' ~ " 'NHITNEY & JEFFREY WALKER 15125 S.E. MAY VALLEY RD r----1 @ I I I I / STRf:AM 8UFF£R i = i /, t::::::, I I LON? MARSH CRt,1<; L---- ~ --~'"r--... I ·---,,,,,__,, I ___, . -IL..---,~~ ir~I Jf,J., IJl~Jc::;;;~~:rr-:!'-',---JO SCALE IN F'EE1 -1 CONTOUR INTERVAL = 1 FT. TEMPORARY EROSION AND SEDIMENT CONTROL NOTES , 1. ALL WORK ON PRNATE PROPERTY Will BE CONSTRUCTED USING A TEMPORARY CONSTRUCTION EASEMENT. THE DRAINAGE SYSTEM ON PRIVATE PROPERlY Will NOT BE MAINTAINED BY KING COUNTY AFTER COMPLETION OF THE PROJECT. 2. THE ESC FACILITIES MUST BE CONSTRUCTED IN CONJUNCTION WITH AU. CL.EARING AND GRADING ACTMTIES,AND IN SUCH A MANNER f,,S TO INSURE THAT SEDIMENT LADEN WATER DOES NOT ENTER THE DRAINAGE SYSTEM OR VIOLATE APPLICABLE WATER STANDARDS. (KCC 9.04.020 M, KCRS 7.09 D). 3. THE PROJECT SHALL BE SCHEDULED FOR CONSTRUCTION IN DRY CONDITIONS. LONG MARSH CREEK SHAU. BE BYPASSED AROUND THE CONSTRUCTION AREA. 4. ALL WORK SHALL COMPLY WITH THE W"8HINGTON STATE DEPARTMENT OF FISH AND WILDLIFE HYDRAULIC PERMIT APPROVAL CONDmoNS. 5. THE PROPERlY OWNERS SHALL BE CONTACTED ONE WEEK PRIOR TO CONSTRUCTION. 6. AFTER COMPLETION OF CONSTRUCTION, THE STAGING AREA AND THE DIRT PATH SHALL BE RESTORED TO ORIGINAL CONDmONS. ALL OTHER DISTURBED AREAS, SHALL BE SCARIFIED, MULCHED AND SEEDED. 7. A SILT CURTAIN, f,,S DIRECTED BY THE WLRD ECOLOGIST OR ENGINEER, SHALL BE DEPLOYED IN THE EVENT OF TURBIDITY PRODUCING ACTIVITY. 8. SEDIMENT LADEN WATER SHALL BE PUMPED INTO AN UNPAVED UPLAND AREA WHERE IT CAN SHEET FLOW THROUGH VEGETATION PRIOR TO RE-ENTRY INTO MAY CREEK. 9. ALL PAVED ROADS USED FOR INGRESS AND EGRESS SHAU. BE KEPT FREE FROM SEDIMENT ACCUMULATION BY SWEEPING AND/OR W"8HING AT LEAST ONCE PER DAY. 10. HAND BROOMS AND OTHER APPROPRIATE TOOLS SHALL BE USED TO REMOVE SOIL ANO ROCKS FROM CONSTRUCTION VEHICLE TIRES PRIOR TO EXITING THE SITE. 11. THE FOLLOWING BMP'S SHALL BE ONSITE OR READILY ACCESSIBLE DURING CONSTRUCTION: MULCH, STRAW WATTl.ES AND/OR STRAW BALES SILT FENCING AND SILT CURTAIN SPILL RESPONSE KIT 12. THE CONSTRUCTION LIMITS OF THIS PROJECT SHALL BE DEFINED BY THE CULVERT ON THE UPSTREAM END, THE EXISTING WIRE FENCE ON BOTH SIDES OF LONG MARSH CREEK AND THE SILT FENCE ON THE DOWNSTREAM END, EXCEPT FOR AN ADDmoNAL 5 FT BEYOND THE FENCE AT THE MAY CREEK SIDE CHANNEL ANO A PORTION OF THE SOUTH SIDE OF LONG MARSH CREEK. TESC LEGEND ~ = ~ ---SF--- -CL- ---"'--- ~ ~ ---=--- TEMPORARY BYPASS PUMP TEMPORARY a·, B'l'PASS PIPE SILT FENCE SILT a.JRTAIN TEMPORARY BYPASS PIPE/HOSE CLEARING LIMITS LINE EXISTING WETLAND BOUNDARY EXISTING STREAM/CREEK CONSTRUCTION ACCESS ROAD CLEARING ANO GRADING LIMITS CALl. 2 WORKING DAYS BEFORE YOU DIQ 1-800-424-5555 (UNDERGROUND UTILITY LOCATIONS ARE APPROX.) APPRO'vlll: Don Althauser, P.E. 17-2011 PRo..ECT MANAGER: Doun Chin 7 2011 ~ King County Department of Natural Resources and Parks Water and Land Resources Division Stom'IW8ter Services Section LONG MARSH CREEK RESTORATION CONR.UENCE TO RM. 0.05 SHEET SWPP1 OF I PROJECT No. DESIGNED: WES KAMEOA, P .E. 7 2011 Julio Tumev LG. 7 2D11 ""I • DESIGN ENTERED: L TRAXINGER 7 2011 I MAINTENANCE DATE --. DIVISION No. 1C1205 Capital Servtees Unit Christie Troe, OnK::tor 4 TBIPClRARY ERCSON AND SEOOIBIT OOH1ROL PLAN AND NOTES 8 SHEETS 2006-42 I I I I I I I I I I I I I I I I I I I FIELD BOOK: SURVEYED: 2010-2 Goulet.Radella SURVEY BASE IIW': Rodello CHECKED: Dale Nelson I I I I I I I JOINTS IN FILTER FABRIC SHALL BE SPLICED AT POSTS. USE STAPLES, WIRE RINGS. OR EQUIVALENT TO ATTACH FABRIC TO POSTS 2"X2'" BY 14 Ga. WIRE OR EQUIVALENT, IF STANDARD STRENGTH FABRIC USED FILTER FABRIC ~-;i~,-:,='"~""""'~ . ~k""~" _y',;?),r/)r>~>'/%):;,~/),)/~)»;;:s; z .%-'% Y/rYhYAY> -Ti---6'MAX--:----=-i, -, I I ' \ ' I I "--MINIMUM 4•,4" TRENCH LJ ~ACKFlLL TRENCH WrTH NATNE SOIL OR 3/4"-1/5" WASHED GRAVEL POST SPACING MAY BE INCREASED TO B' IF WIRE BACKING IS USED rx4" WOOD POSTS, STEEL FENCE POSTS, REBAR, OR EQUIVALENT NOTE: FlLTER FABRIC FENCES SHALL BE INSTALLED ALONG CONTOUR WHENEVER POSSIBLE BALlAST CHAIN SILT FENCE DETAIL NTS ffi Slll'PI ..__, NIVERSAL CONNECTORS MARINE GRADE ALUMINUM FLOTATION NSION CABLE BELOW FLOTATION ~l•I • GROMMETS LACED TOGETHER WITH MANILA ROPE HAIN TENSIONED THROUGH STRESS PLATES, VIA HOOK AND RING CONNECTION SILT CURTAIN (TYPICAL) ffi 9-20101 8-2010 9-2010 9-2010 NUM. NOT TO SCALE EVlSION "" I DAIT SWPP1 ...__.. APPROVED: Don Althauser, P .E. :r~~ Ooun Chin DESIGNED: WES KAMEOA, P.E. Julio Turnev LG. , DESIGN EN'TEREO; L. TRAXINGER z ::, " '-'°S.v11'7z >0-<"<'-<{<:~ N /)J} ,.. ..... -:_,,,,,, // HOG FUEL OR 4 • -s• QUARRY SPALLS OVER GEOTEXTILE FABRIC TEMPORARY CO~STRUCJION ACCESS NTS STEEL PLATE OR SANDBAGS ACROSS WIDTH OF CHANNEL CONSTRUCTION ACCESS NOTES: 1. THE ENTRANCE SHALL BE MAINTAINED IN A CONDITION WHICH WILL PREVENT TRACKING OR FLOW OF MUD ONTO PUBLIC RIGHT-OF-WAY. THIS MAY REQUIRE PERIODIC TOP DRESSING WITH 2• STONE, f,,S CONDmONS DEMAND, AND REPAIR AND/OR CLEAN-OUT OF ANY STRUCTURES USE TO TRAP SEDIMENT. 2. ALL MATERIALS SPILLED, DROPPED, WPSHED OR TRACKED FROM VEHICLES ONTO ROADWAYS OR INTO STORM DRAINS MUST BE REMOVED IMMEDIATELY. 3. PROVIDE TRAFFIC CONTROL AND ROAD SIGNAGE FOR CONSTRUCTION VEHICLES ENTERING AND LEAVING SITE. 4. COORDINATE WITH THE PROPERTY OWNER REGARDING THE EXACT SIZE AND LOCATION OF THE TEMPORARY CONSTRUCTION ACCESS TO AVOID DISRUPTION OF THE HORSE BOARDING ACTIVllY ON THIS PROPERlY. REMOVAL OF THE QUARRY SPALLS MAY BE REQUIRED AITTR THE CONSTRUCTION. 5. HOG FUEL MAY BE SUBSTITUTED FOR THE QUARRY SPALLS DEPENDING ON WEATHER CONDmONS, AT THE DIRECTION OF THE WLRD SITE REPRESENTATIVE. EXISTING [ 4B"• CULVERT .. ,. ... ,. ' .... ·o • ····~-~ s _ = = = c:,.fZ7=· v_.., .. ,::::,. STEEL PLATE AND/OR COFFER DAM SECONDARY PUMP \ TOP OF BAN~ ~1 \ (DOWNSTREAM) ~ 0 \, .. 34ot TO STABLE CHANNEL 17 2011 7-2011 4• PRIMARY PUMP (6" PUMP ON STANDBY FOR WET CONDmONS) -I PROJECT No. 1C1205 7 2011 7 2011 7 2011 I MAINTENANCE · , DIVISION No. 4 2• SECONDARY PUMP ( 4 • PUMP ON STANDBY FOR WET CONDITIONS) -----,~ / .. ~;,~] i~w~L~%1 )'),.~ ,, ~'.;$'§' L-----------TO STABLE CHANNEL, STREAMBED !'.l.m BEYOND ACTIVE WORK AREA (DOWNSTREAM) STEEL PLATE AND/OR SANDBAGS WITI·l 40 MJL POLYETHYLENE SHEETING OR EQUIVALENT ELEVATION TEMPORARY STREAM BYPASS PUMP, DAM AND PIPE DETAIL @ NTS ~ King County Department of Natural Resourt:eS and Parts Water and Land Resources Division Stormwater SeNices Section capita! Service& Unit Christie Troe, Direcb:x LONG MARSH CREEK RESTORATION CONR.UENCE TO R.M. 0.05 TBll'ORARY eioso,.i NiD S8)Q(BIIT DETAD..S SHEET SWPP2 OF 8 SHEETS 2006-42 I I I I I I I I I I I I I I i I I I I I s <!c I \ I <c L ,) 1\ ~ C + I <c I L I \ <c ~-. / t \ /' (), / ''(' \\ / / / /; / ?. / 1 / \ / . / I ' //)\, { ), I"'\ /? \ / + \ / \ / / + . \ \ \ I "' I \ / ', /. I \ f \ / \ "'' / ;, + I \ FlELD BOOK: 2010-2 9-20101 SUINEYED: Goulet,Rodello 8 2010 SUR'I/EY BASE MAP: Rodello 9-2010 CHECKED: Ocie Nelson 9-2010 NUM. 'EV1SION \ I SEC.122, TWN.2,SN, R. 5 E, W\M. \ / < / / NSTALL NEW FENCE / ,,,,, ALONG PROJECT LIMITS ,,- /6 NEEDED ,,,- ~ /; 'V / \ ~ ~ APPROVED: Don Althauser, P .E. PRo..ECT MANAGER: Doug Chin """""' DESIGN; Julio Tumey_!. LG. Lindsey Miller /_, __ ,_i/----· \ LIMITS /,;+-'' ./ // / /' \/ / / ...... ........_.,,_ / /-,../' \ )( \ , ~ ~· ---\ -\ _..,.. -~AROLD AMBINI, \ \ 15 9 S.@\VALLE RD ~ / I \ \ . \ _-/ I / ' I ----) / // / --\+ \ \ \/ '/ /' .,<'5 ' /'/:-\ ,,.,,.-_,l'f';' •/ ~-/"' ' ,_-,,,.,....,_, ,..,,,. . ./' ~, ,_,, ", I ... ..-::::..,~,.-c, ---,,~,,,_.,. .___ _J ~,~ ---~-___ ,,,_ .,...---.~·=·-?\ " / ·-\ I ~\. / \ v \ '"' \ RS rP . ~ // " --- \ \ \ -\ \ 'I ~ ;, "' -~ --.c::::F \ \ I'.'. ~b "/ \/ }, /" <', \;/ I \ \ \ \ \ \ ------LONG ~pRS'r\ cR':-8 st"-°'" ell'"(R-. ..-'"\, 1., c::::Y 1 o,._,o.,,1.---"·. WHITNEY & JEFFREY WALKER 15125 S.E. MAY VALLEY RD _,..-I}) .,.._..--;..\ --s .-,/ i 11 \. ,.,,,-·>-' t~ ~ ,, "'., ~~ \\ .,. -" .- 9, \\ "' '/ "' /' >··-_ _ .... _,-__:;:;. ?--r I '/ -~ ,_,,./'\ ! ---~ / + H.Qll PLANTING NOTES: t ;..(. L ~ ~ :.(. i i 1. PRIOR TO MmGATION CONSTRUCTION, CLEARING LIMITS SHALL BE CLEARLY IDENTIFIED WITH ORANGE PLASTIC FENCING. KING COUNlY'S BIOLOGIST SHALL VERIFY AND APPROVE FENCE LOCATIONS PRIOR TO CONSTRUCTION. 2. CONTRACTOR SHALL ARRANGE TO MEET ON SITE WITH ENGINEER AND BIOLOGIST PRIOR TO THE COMMENCEMENT OF CONSTRUCTION ACTIVITIES TO DISCUSS ACCESS, LIMITS OF WORK AND METHODS. 3. MITIGATION PlANTING PLANS REPRESENT A CONCEPTUAL PLANT LAYOUT. FINAL PlANT LOCATIONS SHALL BE OITTRMINED AT THE TIME OF PLANTING BY THE BIOLOGIST. 4. WITHIN ALL DISTURBED AREAS TO BE PLANTED OR SEEDED, PROVIDE AND INSTALL FOUR (4) INCH DEPTH OF COMPOST ROTOTILl£D TO A TWELVE (12) INCH MINIMUM DEPTH. 5. ALL PlANTS SHALL BE NURSERY GROWN A MINIMUM OF ONE YEAR. PLANT MATERIAL IS TO BE SUPPLIED BY COMMERCIAL NURSERIES THAT SPECIALIZE IN PLANTS NATIVE TO THE PUGET SOUND REGION OF THE PACIFlC NORTHWEST. PLANT SUBSTITUTIONS ARE SUBJECT TO APPROVAL BY KING COUNTY'S BIOLOGIST. 6. PLANTING SHALL TAKE PLACE DURING THE PtANT DORMANCY PERIOD (NOVEMBER 1ST TO MARCH 1ST), OR AS DIRECTED BY KING COUNlY'S BIOLOGIST . 7. THE CONTRACTOR SHAU. BE RESPONSIBLE FOR DISPOSING OF ALL DEBRIS AND EXCESS SOIL EXCAVATED BY THIS PROJECT . 8. CONTRACTOR SHALL VERIFY THE LOCATION OF ALL UTILITIES PRIOR TO EXCAVATION. 9. EXISTING AREAS DISTURBED BY CONSTRUCTION ACTIVmES AND NOT SHOWN TO BE RE-VEGETATED ON THESE PLANS SHALL BE RESTORED AND SEEDED, AS DIRECTED BY THE ENGINEER. 10. DISCREPANCIES BETWEEN THE PLANS AND SITE CONDITIONS SHALL BE BROUGHT TO THE AITTNTION OF THE ENGINEER AND BIOLOGIST PRIOR TO PROCEEDING. 11. NO TACKIFIER. HERBICIDE OR FERTILIZER SHAL..l.. BE USED IN THE STREAM PLANTING AREAS. l!lJ Ml II 20 0 20 l"- SCAl.f IN FEET CONTOUR INTERVAL = 1 FT. 60 CALL 2 WORKINO DAYS BEFORE YOU DIG 1-800-424-5555 {UNDERGROUND UTILITY LOCATIONS ARE APPROX.) SHEEr L1 7-2011 I PROJECT No. 1C1205 7-2011 ~ King County Department of Nab.Hal Rasourt;eS and Parks Water and Land Resources Division Stonnwater Services Section LONG MARSH CREEK RESTORATION CONR.UENCE TO R.M. 0,05 OF 8 7-2011 Capital Services Unit PI..ANT1NQ Pl.AN AND NOlES SHEErS .., '"'11 I MAINTENANCE 4 DMSION No. Christie True, Dit9ctor DESIGN ENTERED: L Troxinger I' ,u I 2006-42 BY I DATE I I I I I I I I I I I I I I I I I I I . Scientific Name Common Quantity Size Conditions · Plant Spacing May Creek Side Channel Name f PAINT OR DIP EXPOSED ENOS OF LIVE STAKE WITH Thuja plicata Western 3 Container min 18" ht "Island" between main and MIN. 12 NODES WHITE LATEX PAINT PRIOR Long Marsh Creek • Red full, dense foliage, • side channel BELOW G~E TO INSTALLATION C d t · I g!S LNE STAKE INSTALLATION, Thuja plica1a westem Red 10 Container min 1s-ht, ruu. dense High flow cttanrtel. s!ope edge locate in e ar symme nca crown 1rp INSTAll. LIVE STAKES AT * . Cedar foliage,symmetricalaown clusterofwalows 1 __ , ~ . MIN. 36" SPACING. INSTALL 0 Comus sericea Red 3 1 gal Container min "Island" between main and c:,ill-_ 1 :.; #J PER DETAIL Osier two stems side channel ~ill " I ~ 0 Betula papyfffera Paper Birch 9 B&8 5-6'_ ht. full, dense foliage, High flow channel within 50 feel of May D wood BEVEL£0 ENO (4Sq) -1 lj I _ symmetncal '"™' Cleek ,0 • OQ IN SOIL 00 NOT LET 'I-, 1=111-- !jj/) Symphoricarpos Snowber 6 1 gal Container min two "Island" between main and DRY ouT , · ,-I ,- O Fraxlnus latifolia Oregon Ash 10 :!' .. ::~:; ~nse foliage, High flow channel, base of s1ope alb us ~ ry s~ems side channel 4 ..... Carex Shore 6 10 cubic inch plugs Low bank along island O c~, .. -. ~ 27 =~~-21"htand-d, CT,s-oflliraeonh~fla.ohan~ I le:::~'::$ s:::~:i 6 10cublclnchplugs ::::~~~~ri:I:: NQIE: ~ Acer circiantum Vine Maple 30 Conlainer 1s• -21• ht and spread, Clusters of three on high flow channel microcarpus ted between main and side POKE HOLE IN SUBGRAOE WITH STEEL BAR. CAREFULLY PtANT STAKE IN V mfntwostems B I h h I HOLE. DO NOT BREAK OFF LEAF NODES. CAREFULLY ARM SOIL AROUND u rus C anne INSTALLED LIVE STAKE TO REDUCE AIR POCKETS. fc--~~~---+=-~--f--=-+.--,,.,---,--=,,---,-=-+=---,-=......,.=c-==· =,,-, Salix iasiandra Pacific 20 Live stake, min 36" long 3 'oc staggered. Stakes ~ Sallxlaslandra Pacific 55 Uvestake,mfn36"tongat%·to 3'ocstaggered.Sta1cesdriven1ntohigt, 0 W"II t""t ,, "d" te d · · t b k d" !rib t d ~ Wlltow %"d~met,.,mm,2 1at9rato,ds 11owchaooeldlS1r1b"1edalonge<ee1< 1 ow a_" o,. 1ame r, nven1_no ans ,s ue LIVE STAKE DETAIL ,3) pe, stake mm 12 lateral buds per along island between May N1S __ stake Creek main and side .___... 0 Salix sitchensis Sitka Wflow 55 Live slake, min 36" tong at%· to 3 'oc staggered Stakes driven alto high O channel :;; ::ieeter, min 12 1atera1buds flow channel distributed along creek Salix sitchensis Sitka 20 Live stake, min 36" long 3 ·oc staggered Stakes Willow at W to % • diameter, driven into banks distributed 0 Rilb1JS spedabafis Salmonberry 30 Container 18'" -21· ht and 16" Clusters at three on high flow Channel min 12 lateral buds per along creek spread. dense, multlple stems stake ~ Symphorlcarpos abus Snowbeny 30 Contafner 15"·18" ht spread, ful Cfustern of three on upper bank ofh~ 'el-flow channel TREE STAKING •ARBOR TIE" OR APPROVED SU8SllTUIE ----, 2" OEPTH AS A MULCH. \ e Ro:;anutkana NootkaRcse 30 Container15"·1B"tilspread,fu1l :::h~::reeonupperbankofhi'1] j ~CPlANT SO THAT TOP ~E: ~~~CH AWAY FROM ~ rl.ANT AT SAME LEVEL 8' -0" "SVC" LODGE POLE PINE A OF ROOT BALL IS \ "'5 GROWN. TOP OF . . -. STAKE, 2" DIA (1 PER TREE) EVEN WITH THE R00ll3ALL TO BE LEVEL Polystlchumm1.a11tum W~ 40 1 Galloncontarnermln3fronds Distributed DRIVEN INTO UNDISTURBED I! FINISHED GRADE FORM SAUCER WITH 3• W/ FINISH GRADE. Swotd 8111 DIAGONALLY SUBSOIL MIN. 24" ~/ CONTINUOUS RIM,~ OEPTH 2" AS A MULCH r-FINISH GRADE AchlfleamUlefollum Yarrow 40 10coblcinchPlugsor4"pot Distributed " ~ A MULCH ,,,-;;, ; HQIE, STAKE ALL TREES 4' " I FORM SAUCER WITH !L!m ~---· ·. rr/.J.!mllli AND TALLER. / -.. : :-~1--~~ !.!r~EXISTING SOIL Anmcw,d"""5 Goar&Beard 40 1o'"blolnohPl"1JS0<4"pot o;stn!Med 3 CONTINUOUS RIM ,1.lJ. 1 .;,.._ I<'; ,:;, • -BACKRU WITH MIXTURE OF l 1 ..... _ !,; ''-~~ ~~~~ I i I , 1/3 COMPOST & 2/3 =--. Telllmagrandiflora Friogerup 40 1ocublclnchPIUOSot4"pot Disbibuted 8ACKflLL WITH MIXTURE OF l 3 ~;;; -·-~ NATIVE SOILS. WATER AND --,!_t~ ~r COMPOST ANO 2/3 NATNE .. --TAMP TO REMOVE AIR . I 11= I=! I l=l I I SOILS. WATER ANO TAMP TO : Z POCKETS. SCAmFY SIDES / , z carex lenticularis Shore Sedge 30 10 cubic inch plugs Ctuslers adjacentto low flow channel REMOVE AIR POCKETS. '° ~ OF PLANTING PITS PRIOR 2x DIAMETER OF \_ w 'i SCARIFY SIDES OF PLANTING TO BACKFlWNG. ROOTBAlL MIN i-::==+c-~-~---+-~~~+-=-t,-,,.-,,-,-,------f-=.--,---c--. -cc-c--c-""7=:c----l PITS PRIOR TO BACKFIWNG. CONE OF HAND • CONE OF HANO FlRMED Scripus mlcrocarpus SmaB-fniled 30 10 cubic Inch plug9 Clusters adjacent to low ffow Channel · FJRMEO TOPSOIL SOIL FOR ALL PLANTS ' .,., .. _ Bulrush PLANTING HOLE FOR ALL PLANTS "BUTTERFLY"' ROOTBALL mili!!mi!;; Oxa · WOQd.sarel 4 ·pot O l<ilMad g/lIB_ ~~ID,'i.,°J'SST~w FOR 6~ ~6o~IA ~~;w;E DEAC OR BROKEN ROOTS. SUCE THROUGH ROOTS CIRCUNG THE BALL. )?;J;j;:· lls oregano 50 IS SUPPORT. INSTALLED SPREAD (•BUTTERFLY") ROOTS ON BARE ROOT & CONTAINERIZED MATERIAL. .,,,,,,.. PERPENDICULARLY PER U.S. . HORT. STANDS. SMALL TREE, SHRUB CONIFEROUS TREE PLANTING {I\ AND GROUND COVER PLANTING ffi NTS --NTS -- '--' '--' CALL 2 WORKING DAYS BEFORE YOU DIG 1-800-424-5555 (UNDERGROUND l/JlU1Y l.OCATJONS ARE APPROX,) .. Don Althounr, P.E. 7-2011 SHEET aELD """"' 2010-2 •-201 . • , --R•f'il King County LONG MARSH CREEK RESTORATION L2 SUFM'l'(O: Goulet,RodeUa B 2010 =~ Doua Chin 7-2011 ~ DeparlmentdNatundRasour,:eeandParb CONR.UENCE TO RM. OaOS OF R<Jdell<J 9-2010 1 •• ..- 1 -, /It PROJECT No. lCl 20S WaterandLandResouroesDMslori 8 ~ 8,1.SE MAP: PLANTlNG Julia Tumey, LG. 7-2011 StmmwatarSetvloosSodkln CHECKED: Dale N'elaon 9-2010 -i ' DESIGN: Lind,._, Millet-7-2011 capHaJServfcaurut PLAN11NQ SCHB)lJLE AND OETAD..S SHEEfS .. .. I -MAINTENANCE Chdst/e nw. Dt9dar" -DESIGN ENlERfD: L Tn:ixm<u!r 7 -20l l OMSION No. 4 2006-42 HUM.. .io,.·u,anu BY OAT[ I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project December 17, 201 o KlngCounty Dep~rt;m~nt of Natural Resources and Par~ Water and Land Resourc·es DiVlslon science Section Klng·Street Center, KSC·Nll-0600 ·201 south Jackson Street, Suite 600 Seattle. WA 98104. Alternate Formats Available 206-296-7380 TIY Relay: 711 Hydraulac ©lllil<dl Hydrologic Ana~ys®s (Q)f the May Cr(ee!l< Channel Rest(Q)rafta(O)D11 Pr<0ject Prepared for: King County Department of Natural Resources and Parks Stormwater Services Section, Capital Services Unit Prepared by: Jeff Burkey Hydrologist King County Water and Land Resources Division Department of Natural Resources and Parks Department of Natural Resources and Parks Water and Land Resources Division (206) 296-6519 mi I I II I I I I I I I I I I I I u I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydro logic Analyses of the May Creek Channel Restoration Project Citation King County. 2010. Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project. Prepared by Jeff Burkey, King County Department of Natural Resources and Parks, Science Section. Prepared for Stormwater Services Section, Capital Services Unit. King County December 20 I 0 Hydraulic and Hydro/ogic Analyses of the May Creek Channel Restoration Project Executive Summary ....................................................................................................................... vi 1.0. Introduction ......................................................................................................................... I 1.1 Study Goals ..................................................................................................................... I 1.2 Study Extent .................................................................................................................... I 2.0. Model System Design ......................................................................................................... 3 2.1 Objectives ....................................................................................................................... 3 2.2 System Overview ............................................................................................................ 3 2.3 HEC-RAS Model Setup .................................................................................................. 3 2.3.1 Survey Data ................................................................................................................. 4 2.3.2 Flow Rate Change Locations ...................................................................................... 5 2.3.3 Channel Roughness ..................................................................................................... 6 2.4 Hydrology ....................................................................................................................... 7 2.4. l Precipitation ................................................................................................................ 7 2.4.2 FT ABLES ................................................................................................................... 8 2.4.3 Refined Estimate of Stream Flow Events for Phase II Sediment Study ..................... 9 2.4.4 Model Validation ...................................................................................................... 15 3.0. Scenario Development ...................................................................................................... 25 3. I. I Model Geometry ....................................................................................................... 25 3.1.2 Typical Channel Cross-Section ................................................................................. 28 4.0. Sediment Transport ........................................................................................................... 30 5.0. Results ............................................................................................................................... 31 5 .1 Improved Channel Conveyance .................................................................................... 3 7 5.2 Updated Flow Frequencies ........................................................................................... 46 5.3 Reduced Duration of Flood Inundation for Smaller more Frequent Events ................. 52 5.4 Flow Rates Competent to Pass Silts through the System ............................................. 54 5.5 Durations of Flow Rates in the Ravine ......................................................................... 56 5.6 Other Considerations .................................................................................................... 57 6.0. References ......................................................................................................................... 58 figures King County ii December 20 I 0 I I I I I • I I I I I ,g D I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Figure I Locator map of study area in May Creek basin ................................................................ 2 Figure 2 Extent of January 2010 King County Survey ................................................................... 4 Figure 3 Gauge monitoring locations ............................................................................................. 9 Figure 4 Flow rates for the December 2007 event.. ...................................................................... IO Figure 5 Flow rates for the January 2009 event.. .......................................................................... 11 Figure 6 Stages for December 2007 event. Note the obvious data errors in station 37G ............. 11 Figure 7 Stages for January 2009 event. Note the missing data for 37G ..................................... 12 Figure 8 Robust Regression (LOWESS-Locally weighted scatter plot smoothing) on Daily Peak Flow Rates from 11/1/1998 through 2/5/2009. X-axis= 37A, Y-axis= 378. Lower graph is a simulation of 378 using the regression and observed with time on the x-axis, and flow rate on the y-axis ................................................................................................................... 13 Figure 9 December 2007 Hydrograph of event ............................................................................ 14 Figure 10 January 2009 Hydrograph of event .............................................................................. 15 Figure 11 Edge of water survey shown in light blue lines ............................................................ 16 Figure 12 January 2010 Hydrograph for King County Gauge 37G (148th Bridge) ..................... 18 Figure 13 Profile of observed water surface elevations for January 8 ( downstream of footbridge) & 22 (upstream of footbridge) with left and right bank elevations (LOB, ROB) plotted .... 19 Figure 14 Example of cross-section where water surface elevation is same elevation as bank elevation (RM 4.974). Obstruction in cross-section is representative of dense canary reed grass on the banks ................................................................................................................. 20 Figure 15 Example of overbank flooding slowly draining back into channel after a storm from 7 days prior (with some minor precipitation 4 days prior). Photo taken 3/19/2010 ............... 21 Figure 16 Observed water surface elevation for January 14, 20 IO at 64 cfs at Parcel #0223059005 footbridge ....................................................................................................... 22 Figure 17 Observed water surface elevation for March 30, 2010 at 48 cfs at three bridges ........ 23 Figure 18 Scenario 7 longitudinal profile in study area. The black line is channel bottom using top of sediment (used in Scenario I) and fuschia color line is profile of channel bottom to firm sediment. ....................................................................................................................... 26 Figure 19 Scenario 8 showing existing conditions and proposed profile after sediment removal (308 ft) and flushing of silts .................................................................................................. 27 Figure 20 Scenario 9 showing existing conditions and proposed profile after sediment removal (309 ft) and flushing of silts .................................................................................................. 28 Figure 21 Typical Channel Geometry of existing (black line) and proposed (fuschia line) ......... 29 Figure 22 Guo-Shields Empirical Curve ....................................................................................... 30 Figure 23 Scenario I (existing conditions) water surface profile for mean annual (filled in water surface) and Conditions Report I year event (blue line with symbols) ................................ 31 King County iii December 20 I 0 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Figure 24 Water surface profiles for the I-year (Conditions Report) for Scenario 1 and 8. Red circle highlights the convergence of profiles at 146th Ave bridge ....................................... 32 Figure 25 Water surface profiles at 50 cfs for Scenario 1 and Scenario 8 .................................... 33 Figure 26 Water surface profiles for the 100 year flood event for Scenario 1 and 8 .................... 34 Figure 27 Water surface elevations (Scenario 1 and 8) for the 100 year (Conditions Report) at the 146th Ave bridge ................................................................................................................... 35 Figure 28 Water surface elevations for the 100 year return period (Current Conditions) at bridge crossing at 143rd Avenue SE for Scenario 1 and 8 .............................................................. 36 Figure 29 Perspective plot for Scenario 1 (Existing Conditions) mean annual flow rate (8.6 cfs at 148th Street) .......................................................................................................................... 37 Figure 30 Longitudinal plot for Scenario 1 (Existing Conditions) water surface profile for mean annual flow rate ..................................................................................................................... 3 8 Figure 31 Perspective plot for Scenario I and 7 (vegetation removal) 50 cfs at 148th Street. Light blue are for existing conditions while dark blue are for Scenario 7 ............................ 39 Figure 32 Water surface profile at 50 cfs for Scenario 1 and 7 .................................................... 40 Figure 33 Perspective plot comparing Scenario I and 7 under mean annual flow rates .............. 41 Figure 34 Perspective plot for Scenario 1 and 8 overbank flooding with 50 cfs at 148th Street. Light blue areas are inundated areas for Scenario 1 and dark blue are Scenario 8 ............... 42 Figure 35 Water surface profile at 50 cfs for Scenario I and 8 .................................................... 43 Figure 36 Water surface elevations for the 2 year return period (229 and 240 cfs) for Scenario 1 and 8 ...................................................................................................................................... 44 Figure 37 Perspective plot for Scenario I and 9 overbank flooding with 50 cfs at 148th Street. Dark blue areas are for Scenario 9, light blue are for Scenario I (existing conditions) ....... 45 Figure 38 Water surface profile at 50 cfs for Scenario 1 and 9 .................................................... 46 Figure 39 Flow Frequencies for existing conditions using USGS 17-8 methodology for flows at 148th Avenue SE (catchment MVL) .................................................................................... 49 Figure 40 Flow Frequencies using USGS 17-8 methodology for proposed project design (Scenario 8) for flows drainging to 148th A veneue SE ........................................................ 50 Figure 41 Flow Frequencies using USGS 17-8 methodology for existing conditions at Coal Creek Parkway ( catchment CCP) ......................................................................................... 51 Figure 42 Flow frequencies using USGS 17-8 methodology for proposed project design (Scenario 8) at Coal Creek Parkway ( catchment CCP) ........................................................ 52 Table 1 Stationing for structures in the HEC-RAS model.. ............................................................ 4 King County iv December 20 I 0 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Chunnel Restoration Project Table 2 Example of Flow Change Locations in HEC-RAS for mean annual flow rate ................. 5 Table 3 Vertical varying roughness by flow rate ............................................................................ 6 Table 4 Monthly scalars to transpose SeaTac precipitation to May Valley ................................... 7 Table 5 Accuracy of robust regression for simulated versus observed for gauging station 3 78 using linear regression statistics, with observed on the x-axis for slope .............................. 14 Table 6 Water surface observations, elevations in NAVD88 ....................................................... 16 Table 7 Summary of flood frequencies for Scenario I and Scenario 8 for May Creek in the valley ..................................................................................................................................... 47 Table 8 Summary of flood frequencies for Scenario I and Scenario 8 for May Creek in the ravine ..................................................................................................................................... 47 Table 9 Percent of time flows are equaled or exceeded at each of the flow rate thresholds for flows passing through the project area ( catchment MVL outlet at 148 1h Avenue SE) based on HSPF simulation WY 1949 -WY 2008 .......................................................................... 53 Table IO HEC-RAS calculated shear stress in channel for Scenario 8, mean annual equals 8.6 cfs. Zero shear stresses are highlighted in tan color ............................................................ 5 5 Table 11 Percent of time flows are equaled or exceeded at each of the flow rate thresholds for flows in the ravine ( catchment CCP) based on HSPF simulation WY 1949 -WY 2008 (525,960 hours) ..................................................................................................................... 56 King County V December 2010 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project EXECUTIVE SILIJMMARY May Creek in May Valley routinely flows out of channel inundating adjacent pastures and wetlands during the wet season. At the downstream end of the valley, the natural landscape constrains stream flows back into channel controlling flow rates leaving the valley before entering the ravine. This feature, coupled with the flat pasture lands, are reasons why flooded areas in the valley can take several days to sufficiently drain; returning to usable pasture lands. Combine this with a frequent occurrence of small storms and portions of the pasture lands expectedly remain unusable for much of the wet season with frequent undesirable inundation continuing through spring and into the summer months. Given these conditions, the proposed project focuses on areas upstream leaving the natural constricting features unaltered. A study was conducted for May Creek in May Valley to evaluate stream channel capacity for existing and proposed conditions. This report contains hydrologic and hydraulic analyses (H&H) used to help optimize project design. Analyses include: assessment of channel capacity for existing and proposed designs, assessment of flood frequencies and durations, assessment of channel competency to mobilize fine sediments and improve lifespan of the project, and assessment of impacts to erosivity in the ravine downstream of 148 1h Ave SE. Two types of models were used, HSPF and HEC-RAS. HSPF is an U.S. EPA hydrologic watershed model used extensively in the Puget Sound region. The original model used was developed for the May Creek Current and Future Conditions report (King County 1995). This model was updated with more current meteorology and channel routing to improve understanding of stream responses with longer periods of precipitation record and more accurate hydraulics. The HEC-RAS model used was last modified by Otak in 2006. For this study, new land survey work was completed in 2010 to update channel geometry and enhance resolution specific to this project study area, supporting simulation of several proposed channel restoration activities to reduce frequency of flooding without significant downstream impacts. At the lowest point in channel capacity under existing conditions, it is estimated that May creek begins to flow overbank at approximately 6 cubic feet per second (cfs). This flow rate is below the estimated mean annual flow rate of 9 cfs. Thus for most of the wet months, small portions of the pasture susceptible to these minor exceedences will remain inundated. Additionally, a tributary (Long Marsh Creek) historically deposits large gravels from a mostly forested subbasin in May Creek just upstream of a footbridge (approximately at river mile 4.6). These gravel deposits are large enough to backwater May Creek upstream for a couple thousand feet. This backwater condition facilitates the recruitment of more fines and vegetation litter that decays into organic muck. This muck then allows for an increase of vegetation encroachment of the channel further reducing channel capacity. The project study proposes an excavation of the channel between 148 1h Ave SE and approximately 2000 feet upstream to an elevation of 308 ft (NA VD 88). Additionally, dense vegetation choke points downstream of 148'h Ave SE will be thinned to reduce impediment of low flows exiting the valley heading to the ravine. Hydraulic analyses estimate that post project channel capacity will be increased from 6 cfs to approximately 50 cfs before overbank flows begin. This improvement will effectively reduce most small storms from flooding the pasture areas. However, this channel improvement is still below the magnitude of an annual storm, thus May Valley is still expected to flood annually, but with shorter duration. This change in low King County vi December 20 I 0 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydro logic Analyses of the May Creek Channel Restoration Project flow hydraulics frees up overbank storage for larger storms, such that results of this study estimate that storm events greater than the JO-year will either remain the same or marginally reduce in peaks. Storm events between the I-year (approximately 10% increase) and the IO-year (approximately 1% increase) slightly increase, with all estimated increases or decreases calculated within model accuracy of a calibrated hydro logic model. Durations of flows near the 2-year (i.e. 200 cfs) and above are essentially the same. Durations of flows at I 00 cfs again are nearly the same with an estimated difference in durations of approximately 400 hours over a 60 year period (525,960 hours, 0.08%). The higher the flow rates the less difference in durations to be expected. Sediment mobility was also evaluated to estimate expected lifespan of the project. Channel bottom sediments in the project area are comprised mostly of silty fines and organic muck. With this type of channel bottom, it's estimated that a shear stress ofO.Ol pounds per square foot is required to move sediment downstream. A mean annual flow rate (i.e. 9 cfs) was selected to evaluate success of the project given that flows at or above the mean annual level occur during most of the year, thus minimizing the possibility of any significant recruitment of fines or vegetation re-establishing in the channel. Post project, estimates of shear stress at 9 cfs are at or above 0.0 I psf except downstream of 1481h Ave SE in the wetland. There at low flows, deposition is expected to occur similar to existing conditions. These results signify that given the management of gravel deposition from Long Marsh Creek and ability to mobilize fines in May Creek, post project conditions should continue into the future with minimal deposition of fines reducing intended channel capacity. Based on the sediment transport study conducted downstream in the ravine (King County 2009), channel sediment mobilizes approximately at 233 cfs (refined from original flow rate estimates of275 cfs). This estimate along with marginal changes in durations of flows (maximum difference at 100 cfs with 0.08%), suggest no significant downstream impacts in the ravine resulting from proposed project designs. It is acknowledged that there is a level of uncertainty in estimates of stream channel sediment mobilization thresholds that could be lower. Given the maximum estimated difference in durations (at 100 cfs) is approximated to an annual average increase of 7 hours during the course of a year; these effects would likely be undetectable in the ravme. King County vii December 20 I 0 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project May Creek valley experiences out of bank flooding on a routine basis every wet season lasting from several days to weeks at a time. The stream course is essentially in a bowl for approximately 2100 feet (river mile 4.6 to 5.0) between a footbridge upstream of Parcel #0223059005 property down to Long Marsh confluence-just upstream of another footbridge. Long Marsh is primarily a forested basin with steep gradients. This characteristic gives the tributary the ability to deposit gravels large enough that May Creek is not capable to redistribute gravels downstream. Thus stream bed elevations at this location rise as more gravels are deposited. This accumulation then backwaters May Creek upstream causing more deposition of fines and decaying vegetation-ultimately reducing conveyance capacity and increasing frequency of valley flooding. Like any natural stream system, larger but less frequent flow rates perform work on the stream banks and bed. Downstream of the valley, May Creek drops into a ravine where channel forming processes are expected. A recent sediment transport study was conducted at three locations in the ravine between Coal Creek Parkway and 148 1h Ave SE (King County 2009) characterizing conditions capable of causing erosion in the ravine. Those results are used to evaluate effects of this proposed study. "il .11 Slhndy Gcaias The goal of this study is to evaluate channel capacity for different alternatives in the valley area to maintain flow rates near I-year flood return interval by showing a reduction in frequency and duration of flooding. The reduction in duration of flooding is intended to affect only the most frequent, smaller storms, therefore unlikely to have any significant impact to the larger storms capable of eroding downstream conditions. Additionally, the proposed conveyance improvement should also be sustainable by passing through silts and retarding buildup of fines. In order to perform these types of analyses, a combination of techniques was necessary to evaluate detailed hydraulics and hydrology. Two types of models were used to perform the analyses, HEC-RAS for hydraulics and HSPF (Bicknell 2005) for hydrology. Both models used were adapted from existing models and updated to reflect current conditions. HEC-RAS (USACE 2005) was used to evaluate channel conveyance capacities and flooding inundations, while HSPF was used to provide statistical measures of durations and magnitudes of storm events. While the extent of the proposed channel improvements extend from river mile 4.31 up to river mile 4.99 (yellow highlight in Figure I), it was necessary to extend the boundary conditions to support the ravine erosion analysis and include the lower portions of the HEC-RAS hydraulic model down to the Coal Creek Parkway, river mile 3.59 (model extent shown as cross-sections in green in Figure I). Similarly, the watershed model used encompasses the entire basin as shown in light red in Figure I. King County 1 December 20 I 0 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses <Jf the May Creek Channel Restoration Project ' ~ "· 0 t':, ~- cl r., Figure I Locator map of study area in May Creek basin. King County 2 December 2010 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Model design was dependant on available information and intended goals of the project. Modeling of the May Creek system included a hydrologic (HSPF) and hydraulic model (HEC- RAS). The hydrologic model used was developed for the May Creek Current and Future Conditions report (King County 1995), while the HEC-RAS model was based on multiple modifications over time (King County 1995, Entranco 2002, Otak 2006) as projects occurred, with the most recent modifications performed by Otak in 2006. 2. "ii ~lbjecilfives The model system setup was designed to address May Creek Capital Improvement Project restoring hydraulic capacity with these objectives: I. assess channel capacity for existing and proposed designs, 2. assess changes in flood frequencies and durations, 3. assess channel competency to mobilize fines in May Creek through the valley, and 4. assess impacts to erosivity in the ravine downstream of 148 1h Ave SE. In order to evaluate the stochastic nature of stream hydrology, it was necessary to perform a deterministic evaluation of the flow rates in the ravine and valley. Using the backwater computational abilities ofHEC-RAS, channel routing tables (FT ABLES) were created to provide a detailed characteristic of reaches in May Creek in HSPF. Then using HSPF, hourly continuous stream flow data are simulated through the May valley and ravine. By simulating continuous hydrologic conditions for multiple decades (i.e. 60 years), the sequencing and permutations of selecting shapes and magnitudes of storm events are not needed. This framework then allows for a comprehensive durational analysis of exceedances of flow rates that inundate the valley and exceedances of flows above the incipient motion threshold in the ravine. An existing model was used as a starting point for updating existing channel geometry with recent survey data collected in January 20 I 0. Outside of the surveyed area, existing model definitions were used. Additionally, there was the intent to use the same stationing for location of cross-sections as was previously defined in the model within the surveyed area with cross- sections added where recent survey data suggested a change in topography that may not have been present in the previous modeling efforts. This included a denser set of cross-section stationing to better encapsulate undulations of the stream profile where adverse slopes between segments were common or where vegetation choke points are occurring .. The existing model domain started a short distance downstream of Coal Creek Parkway, to two- thirds of a mile upstream of where May Creek crosses May Valley Road at S.R. 900 (a little over 4 miles in total). King County 3 December 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project 2.3.1 Survey Data King County recently surveyed much of the lower valley starting at Parcel #0323059038 property (approximately 950 ft downstream of 148 1h), to approximately 640 ft upstream of Parcel #0223059005 lower footbridge-approximately 3800 ft of stream length, during the month of January 20 I 0. This surveyed area coincides with river miles: 4.266 through 4.99 (Figure 2). To further extend the model cross-sections from valley wall to valley wall, ground elevations using LiDAR data were used. Given the comprehensive extent of the field survey work, the addition ofLiDAR was more for visualization rather than included in any of the hydraulic computations. The one exemption in the recent survey data were any bridge geometries upstream of l 48'h street (including 148 1 1, Street bridge). For these structures, existing geometry in the HEC-RAS model was used (see Table I for longitudinal stationing). Figure 2 Extent of January 2010 King County Survey Table l Stationing for structures in the HEC-RAS model Station Description 7.07 Bridge-May Valley Road 6.95 Bridge-Renton-Issaquah Road King County 4 December 20 I 0 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project 5.87 Bridge-164th Avenue SE 5.04 Footbridge-Upstream of Parcel #323059038 4.868 Footbridge-Parcel #323059038 4.612 Footbridge-McFarland's 4.455 Bridge-148th Avenue SE 4.28 Bridge-146th Avenue SE 4.265 Weir-Partial rock weir 4.114 Bridge-143rd Avenue SE 2.3.2 IFOow Rate Clhlami!BJe ll.ocatio1111s In a stream system where tributaries occur or where attenuations from in-channel and overbank storage volumes reduce peak flow rates, a defined water surface profile may have changing flow rates associated to a set of cross-sections in the model. These flow rate changing locations in the hydraulic model were derived from two methods; either using observed gauge flows or results from continuous hydrologic model (HSPF). Statistical type flows such as mean annual, or 2 yr, etc., are based on outputs of the HSPF model, while any specific flow rate events evaluated were based on gauge data. In the hydraulic model, there were five defined inflow points starting near the headwaters as the upstream inflow down to where two lateral tributaries drain into the wetland on Open Space 803540, west of 148 1 h Ave SE. River mile stations for the flow change locations defined in the model are: o River mile: 7.605 (defined as catchment outlet NFK), head waters of May Creek o River mile: 7.05 (defined as aggregation of catchment outlets: NFK, EFK, and LKC), confluence of North Fork, East Fork, and Lake Kathleen, at SR-900 o River mile: 6.943 (defined as catchment outlet MVM), local drainages feeding to downstream of 1641h Ave SE o River mile: 5.277 (defined as catchment outlet MVL), drainages leading to 148 1h Ave SE o River mile: 4.388 (defined as catchment outlet CCP), drainages leading to Coal Creek Parkway. As an example, the mean annual water surface profile is defined using the stationing from above. Flow rates start at the headwaters with 4.6 cfs, and accumulate to 13.6 cfs entering into the ravine. Table 2 Example of Flow Change Locations in HEC-RAS for mean annual !low rate Station mean annual King County 5 December 20 I 0 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 2.3.3 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project 7.605 7.05 6.943 5.278 4.388 Channel Roughness (cfs) 4.6 10 8.4 8.6 13.6 Defined channel roughness followed previous modeling efforts developed by Otak. Essentially, channel reaches with substantial reed canary grass or collections of willow tree root systems were simulated with a channel roughness decreasing with increasing flow rates (Table 3). Otherwise, channel roughness in continuously choked reaches has a constant channel roughness of 0.07 and where channel was assumed clear, a roughness of 0.04. In addition to channel roughness, obstructions were used represent effective blockages either from dense clusters of willow trees, or heavy mats of canary reed grass on the banks. Table 3 Vertical varying roughness by flow rate Manning 1s n Flow Rate Left Right (cfs) Bank Channel Bank 5 0.080 0.089 0.080 10 0.070 0.081 0.070 25 0.065 0.060 0.065 50 0.065 0.051 0.065 75 0.055 0.047 0.055 100 0.055 0.045 0.055 125 0.055 0.042 0.055 150 0.050 0.040 0.050 175 0.050 0.039 0.050 200 0.050 0.037 0.050 King County 6 December 20 I 0 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Manning 1s n Flow Rate Left Right (cfs) Bank Channel Bank 250 0.050 0.036 0.050 300 0.050 0.035 0.050 350 0.050 0.034 0.050 2.~ ll=llydroDoeiy A numerical hydrologic model (HSPF) developed for the 1995 May Creek Current and Future Conditions Report was used to simulate the hydrologic regime for a 60 year period. To generate this long period of record, the National Weather Service Sea-Tac metrological station was used for precipitation, and the Washington State University Puyallup station was used for evapotranspiration (ET). The period of record simulated was from water year 1949 through water year 2008 (10/1/1948-9/30/2008). 2.4.11 lfl>recipotatoon Precipitation is processed to hourly intervals, while the ET is processed to daily increments. However in the lower Puget sound basin, the Cascade foothills topography create an orographic effect of increasing precipitation the further east and closer to the mountain range. As a result, the observations made at Sea-Tac station needs to be translated to the May Valley basin. There are any number of ways of doing this, one typical way is to scale precipitation using mean annual ratios of Sea-Tac to any local data in the basin. In general, this will provide a means for representing annual runoff volumes, but the scalar can be greatly divergent for a given season ( e.g. over estimate storms in the winter and under estimate in the summer). This technique was used in the original Conditions report model. However, for this project a slightly more sophisticated technique was used to better preserve the individual seasons (i.e. by month). In May Valley, there were two local precipitation stations used to scale the Sea-Tac data (King County station 37u for the lower parts of the valley, and 37v for the upper elevations of the valley. The Sea-Tac data were then scaled on a monthly basis using linear regressions with a constant of 0.0 for each month, such that zero precipitation at SeaTac will be zero precipitation in May Valley. This allows for closer approximation of seasonal variability. Thus, in the HSPF model where one would use a scalar to adjust the Sea-Tac precipitation, the scalar is kept at 1.0 since the scaling was done prior to the model run. Monthly Scalars are listed in the table below. Table 4 Monthly scalars to transpose SeaTac precipitation to May Valley. SeaTac SeaTac Month to 37V to 37U January 1.172 1.044 February 1.150 1.096 King County 7 December 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project SeaTac SeaTac Month to 37V to 37U March 1.252 1.197 April 1.270 1.150 May 1.555 1.378 June 1.311 1.283 July 1.785 1.438 August 1.187 1.163 September 1.462 1.272 October 1.352 1.158 November 1.178 1.069 December 1.112 1.064 2.4.2 IFTABLES FT ABLES are user defined channel routing tables characterizing the relationship between stage, surface area, storage volumes, and flow rates. Four of these FT ABLEs were modified to reflect the hydraulics modeled using HEC-RAS. Using the multiple flow rate profiles defined in HEC- RAS ranging from mean annual flow rates to 100-year flood frequencies, a series of cross- sections were used to define the transient storage HSPF utilizes for kinematic wave routing. For every cross-section in HEC-RAS the stage and wetted area can be highly distinct, thus an average was developed for each of the four catchments in HSPF. The groupings of cross- sections per catchment are listed below: o RM 3.5 though 4.451 were used for HSPF catchment CCP-FT ABLE 100 o RM 4.53 through 5.49 were used for HSPF catchment MVL-FT ALBE 80 o RM 5.69 through 5.86 were used for HSPF catchment MVM-FT ABLE 70 o RM 5.87 through 6.84 were used for HSPF catchment CFO-FT ABLE 60. The depth and flow rates are weighted averages using the downstream channel length defined in HEC-RAS. Surface areas and storage volumes are summed up for each group of cross-sections defined above. While the overall differences are minor, this was performed for each geometric scenario and inserted into the HSPF scenarios for durational analyses. King County 8 December 20 I 0 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project 2.4.3 !Refined IEstl:imatl:e of Stream Flow IEventl:s for !Plhlase 00 Sedimentl: Si:P.11dly During the sediment study time period, there were two significant storm events that occurred, December 2007 and January 2009. Recorded stream flows during those events were determined to be unreliable (see Phase II, May Creek Sediment Transport Study). Additional investigation into estimating the magnitude of those two events was instructional to better understanding the sediment mobilization that occurred during the two events. Flows at stations: 37 A, 378, May2, and 37G were evaluated for the two defining storm events (December 2007, January 2009) used to estimate incipient motion, 37H was not installed until WY 2010. At stations May! and May3 no flow estimates were done, only stage was recorded (see Figure 3 for locations). Because it has been reported of active erosion/deposition influencing water levels at 378, during the January 2009 event there is more uncertainty for flow estimates. Additionally, using a scaling method to synthesize records at 378, Anchor estimated the peak flow rates for December 2007 and January 2009 to be very similar (339 and 348 cfs, respectively). However, upon further investigation the estimate used for the December 2007 event was based on a peak at 37 A not appropriate for transposition to monitoring station 378. Figure 3 Gauge monitoring locations The peak flow for the December 2007 event at 37 A was near 600-cfs; however, that peak clearly occurs prior to the peaks measured upstream at the various continuous recording stations. King County 9 December 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of th e May Creek Channel Res toration Project Figure 1 Lo c ator map of study area in May Creek basi n . King County 2 Decemb er 20 I 0 Hydraulic and Hydrologic Analyses of th e May Creek Channel R estoration Project 2 .0 . MODEL SYSTEM DESIGN Model design was dependant on available information and intended goals of the proj ect. Modeling of the May Creek system included a hydrologic (HSPF) and hydraulic model (HEC- RAS). The hydrologic model used was developed for the May Creek Current and Future Conditions report (King County 1995), while the HEC-RAS model was based on multiple modifications over time (King County 1995, Entranco 2002, Otak 2006) as projects occurred, with the most recent modifications performed by Otak in 2006. 2.1 Objectives The model system setup was designed to address May Creek Capital Improvement Proj ect restoring hydraulic capacity with these objectives : 1. assess channel capacity for existing and proposed designs, 2. assess changes in flood frequencies and durations , 3 . assess channel competency to mobilize fines in May Creek through the valley, and 4 . assess impacts to erosivity in the ravine downstream of 148 th Ave SE. 2.2 System Overview In order to evaluate the stochastic nature of stream hydrology, it was necessary to p erform a deterministic evaluation of the flow rates in the ravine and valley. Using the backwater computational abilities ofHEC-RAS, channel routing tables (FTABLES) were created to provide a detailed characteristic of reaches in May Creek in HSPF . Then using HSPF, hourly con tinuous stream flow data are simulated through the May valley and ravine . By simulating continuous hydrologic conditions for multip le decades (i .e. 60 years), the sequencing and permutations of selecting shapes and magnitudes of storm events are not needed. This framework then allows for a comprehensive durational analysis of exceedances of flow rates that inundate the valley and exceedances of flows above the incipient motion threshold in the ravine. 2.3 HEC-RAS Model Setup An existing model was used as a starting point for updating existing channel geometry with recent survey data collected in January 2010. Outside of the surveyed area, existing model definitions were used. Additionally, there was the intent to use the same stationing for location of cross-sections as was previously defined in the mode l within the surveyed area with cross- sections added where recent survey data suggested a change in topography that may not have been present in the previous modeling efforts . This included a den ser set of cross-section stationing to better encapsulate undu lations of the stream profile where adverse slopes betwee n s egments were common or where vegetation choke points are occurring .. The existing model domain started a short distance downstream of Coal Creek Parkway, to two- thirds of a mi le upstream of where May Creek crosses May Valley Road at S .R . 900 (a little over 4 miles in total). King County 3 D ecember 2010 I I I I I I I I I I I I I I ·I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydro/ogic Analyses of the May Creek Channel R estoration Project 2.3.1 Survey Data King County recently surveyed much of the lower valley starting at Parcel #0323059038 property (approximately 950 ft downstream of 148th), to approximately 640 ft upstream of Parcel #0223059005 lower footbridge-approximately 3800 ft of stream length, during the month of January 20 l 0. This surveyed area coincides with river miles: 4.266 through 4.99 (Figure 2). To further extend the model cross-sections from valley wall to valley wall, ground elevations using LiDAR data were used. Given the comprehensive extent of the field survey work, the addition of LiDAR was more for visualization rather than included in any of the hydraulic computations. The one exemption in the recent survey data were any bridge geometries upstream of 148th street (including 1481h Street bridge). For these structures, existing geometry in the HEC-RAS model was used (see Table l for longitudinal stationing). Footbridge: Parcel # 0323059038 Figure 2 Extent of January 2010 King County Survey Table l Stationing for structures in the HEC-RAS model 7.07 Bridge-May Valley Road 6.95 Bridge-Renton -Issa quah Road King County 4 December 2010 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Projec t 5.87 Bridge-164th Avenue SE 5.04 Footbridge-Upstream of Parcel #323059038 4.868 Footbridge-Parcel #323059038 4.612 Footbridge-McFarland's 4.455 Bridge-148th Avenue SE 4.28 Bridge-146th Avenue SE 4.265 Weir-Partial rock weir 4.114 Bridge -143rd Avenue SE 2.3.2 Flow Rate Change Locations In a stream system where tributaries occur or where attenuations from in-channel and overbank storage volumes reduce peak flow rates, a defined water surface profile may have changing flow rates associated to a set of cross-sections in the model. These flow rate changing locations in the hydraulic model were derived from two methods; either using observed gauge flows or results from continuous hydrologic model (HSPF). Statistical type flows such as mean annual, or 2 yr, etc., are based on outputs of the HSPF model, while any specific flow rate events evaluated were based on gauge data. In the hydraulic model, there were five defined inflow points starting near the headwaters as the upstream inflow down to where two lateral tributaries drain into the wetland on Open Space 803540, west of 1481h Ave SE. River mile stations for the flow change locations defined in the model are: • River mile: 7.605 (defined as catchment outlet NFK), head waters of May Creek • River mile: 7.05 (defined as aggregation of catchment outlets: NFK, EFK, and LKC), confluence of North Fork, East Fork, and Lake Kathleen, at SR-900 • River mile: 6.943 (defined as catchment outlet MVM), local drainages feeding to downstream of 1641h Ave SE • River mile: 5.277 (defined as catchment outlet MVL), drainages leading to 148'h Ave SE • River mile: 4.388 (defined as catchment outlet CCP), drainages leading to Coal Creek Parkway. As an example, the mean annual water surface profile is defined using the stationing from above. Flow rates start at the headwaters with 4.6 cfs, and accumulate to 13.6 cfs entering into the ravine. Table 2 Example of Flow Change Locations in HEC-RAS for mean annual flow rate King County 5 December 2 010 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 2.3.3 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project 7.605 7.05 6.943 5.278 4.388 Channel Roughness (cfs) 4.6 10 8.4 8.6 13.6 Defined channel roughness followed previous modeling efforts developed by Otak. Essentially, channel reaches with substantial reed canary grass or collections of willow tree root systems were simulated with a channel roughness decreasing with increasing flow rates (Table 3). Otherwise, channel roughness in continuously choked reaches has a constant channel roughness of 0.07 and where channel was assumed clear, a roughness of 0.04. In addition to channel roughness, obstructions were used represent effective blockages either from dense clusters of willow trees, or heavy mats of canary reed grass on the banks. Table 3 Vertical varying roughness by flow rate Manning's n Flow Rate Left Right (cfs) Bank Channel Bank 5 0.080 0.089 0.080 10 0.070 0.081 0.070 25 0.065 0.060 0.065 so 0.065 0.051 0.065 75 0.055 0.047 0.055 100 0.055 0.045 0.055 125 0.055 0.042 0.055 150 0.050 0.040 0.050 175 0.050 0.039 0.050 200 0.050 0.037 0.050 King County . 6 December 20 I 0 ------------------------------------------------- Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Manning's n Flow Rate Left Right (cfs) Bank Channel Bank 250 0.050 0.036 0.050 300 0.050 0.035 0.050 350 0.050 0.034 0.050 2.~ lHydl!'0009Jlf A numerical hydrologic model (HSPF) developed for the 1995 May Creek Current and Future Conditions Report was used to simulate the hydrologic regime for a 60 year period. To generate this long period of record, the National Weather Service Sea-Tac metrological station was used for precipitation, and the Washington State University Puyallup station was used for evapotranspiration (ET). The period of record simulated was from water year 1949 through water year 2008 (10/1/1948 -9/30/2008). 2.4.il Precipitation is processed to hourly intervals, while the ET is processed to daily increments. However in the lower Puget sound basin, the Cascade foothills topography create an orographic effect of increasing precipitation the further east and closer to the mountain range. As a result, the observations made at Sea-Tac station needs to be translated to the May Valley basin. There are any number of ways of doing this, one typical way is to scale precipitation using mean annual ratios of Sea-Tac to any local data in the basin. In general, this will provide a means for representing annual runoff volumes, but the scalar can be greatly divergent for a given season ( e.g. over estimate storms in the winter and under estimate in the summer). This technique was used in the original Conditions report model. However, for this project a slightly more sophisticated technique was used to better preserve the individual seasons (i.e. by month). In May Valley, there were two local precipitation stations used to scale the Sea-Tac data (King County station 37u for the lower parts of the valley, and 37v for the upper elevations of the valley. The Sea-Tac data were then scaled on a monthly basis using linear regressions with a constant of 0.0 for each month, such that zero precipitation at SeaTac will be zero precipitation in May Valley. This allows for closer approximation of seasonal variability. Thus, in the HSPF model where one would use a scalar to adjust the Sea-Tac precipitation, the scalar is kept at 1.0 since the scaling was done prior to the model run. Monthly Scalars are listed in the table below. Table 4 Monthly scalars to transpose SeaTac precipitation to May Valley. SeaTac SeaTac Month to 37V to 37U January 1.172 1.044 February 1.150 1.096 King County 7 December 20 I 0 I I I I I I I I I I I I I I I I I I I 'I I I I I I I I I I I I I I I I Hydraulic and Hy drologic Analyses of th e May Creek Channel Restoration Project Mar ch 1.252 1.197 April 1 .270 1.150 May 1.555 1.378 June 1 .311 1.283 July 1 .785 1.438 August 1.187 1.163 September 1.462 1.272 October 1.352 1 .158 November 1.178 1.069 December 1.112 1 .064 2.4.2 FTABLES FT ABLES are user defined channel routing tables characterizing the relationship between stage, surface area, storage volumes, and flow rates. Four of these FTABLEs were modified to reflect the hydraulic s modeled using HEC-RAS . Using the mu ltiple flow rate profiles defined in HEC - RAS rangin g from mean annual flow rates to 100-year flood frequencie s, a se ri es of cross- section s were used to define the transient storage HSPF utilizes for kinematic wave routing. For every cross-section in HEC-RAS the stage and wetted area can be highly distinct, thu s an average was developed for each of the four catchments in HSPF. The groupings of cross- sections per catchment are listed be low : • RM 3 .5 though 4.451 were used for HSPF catchment CCP-FT ABLE 100 • RM 4 .5 3 through 5.49 were used for HSPF catchment MVL-FT ALBE 80 • RM 5.69 through 5.86 were used for HSPF catchment MVM-FT ABLE 70 • RM 5.87 through 6 .84 were u sed for HSPF catchment CFD-FTABLE 60. The depth and flow rates are weighted averages using the downstream channel length defined in HEC-RAS. Surface areas and storage volumes are summed up for each group of cross-sections defined above. While the overall differences are minor , this was performed for each geometric scenario and inse rted into the HSPF scenarios for durational analyse s . King County 8 December 2010 Hydraulic and Hydro/ogic Analyses of th e May Creek Channe l Restoration Proj ect 2 .4.3 Refined Estimate of Stream Flow Events for Phase II Sediment Study During the sediment study time period, there were two significant storm events that occurred, December 2007 and January 2009. Recorded stream flows during those events were determined to be unreliab le (see Phase II, May Creek Sediment Transport Study). Additional investigation into estimating the magnitude of those two events was instructional to better understanding the sediment mobi lization that occurred during the two events. F lows at stations: 37 A, 37B, May2 , and 37G were evaluated for the two defining storm events (December 2007, January 2009) used to estimate incipient motion, 37H was not installed until WY 2010. At stations Mayl an d May3 no flow estimates were done, only stage was recorded (see Figure 3 for locations). Because it has been reported of active erosion/deposition influencing water levels at 37B, during the January 2009 event there is more uncertainty for flow estimates. Additionally, using a scaling method to synthesize records at 37B, Anchor estimated the peak flow rates for December 2007 and January 2009 to be very similar (339 and 348 cfs, respectively). However, upon further investigation th e estimate used for the December 2007 event was based on a peak at 37 A not appropriate for transposition to monitoring station 37B. Figure 3 Gauge mo nitor ing locations The peak flow for the December 2007 event at 37 A was near 600-cfs; however, that peak clearly occurs prior to the peaks measured upstream at the various continuous recording stations. King County 9 December 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Moreover, there is a considerable area of highly developed landscape draining to 37 A below 37B. This drainage area with relatively high amounts of impervious would respond to an event significantly faster than the upper May Valley basin. This is illustrated by overlaying the various hydrographs for the December event (Figure 4). Thus, even though the daily peak flow rates for the various stations do occur within the same day, the peak event at 37A used should be just below 500 cfs--rather than the near 600-cfs for that event. 400 -37A -May2 .. 379 300 -37G 200 ok===-~~~::.___JL __ _J _________ J 1211/2007 0:00 12/212007 0:00 12/3/2007 0:00 12/4/2007 0:00 12/5/2007 0:00 1216/2007 0:00 121712007 0:00 Figure 4 Flow rates for the December 2007 event Conversely, while the fast response of the lower drainage areas presents themselves in the January 2009 event (Figure 5), that local maximum is less than the daily maximum coincident with the other stations. Thus the daily peaks used for the January 2009 event should be near 600-cfs at 37a (as was previously used). While the citation for the basis of the censoring the multiple years of continuous stream gauge records for 37a and 37b is provided, two apparent actions were taken in pre-processing the data: 1) data were split into high flow and low flow events, and 2) some periods of record were filtered for use. Given the survey results at monitoring station May2, there were minor changes in channel geometry between the beginning and the end of the sediment study. Therefore, the continuous water level measured at that station was assumed to remain consistent throughout the sediment study period with possibly small adjustments to the associated flow rates. Thus all else being equal, a greater depth at that location would coincide with greater flows-assuming no downstream conditions influence the gauge. Reviewing the stages at May2 (Figure 6 and Figure 7) for those two events, January 2009 was observed to have a stage approximately 0.5-ft higher than the December 2007 event. Thus, it is assumed the flows during the January event were greater than the 2007 event. King County IO December 20/0 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project 700 ·~------------------------------~ 600 -----------------------------l 500 400 ·'------- 300+-----------------f---l---------------1 200 '-------- o-1----------------------------------" 11112009 0:00 11312009 0:00 115/2009 0:00 1ll/2009 0:00 1/912009 0:00 1/11/2009 0:00 1/13/2009 0:00 1/1512009 0:00 Figure 5 Flow rates for the January 2009 event 10 ~-------------------------------~ 9 8 ----------• ·~ 7'----------~ ~\·-------'---"-----------------1 6 -1-------- 5'------=. .e~~~------------======= 3 .._ ________ ------------------------- 21----------- o -<-----------------------------------~ -37A -May2 •378 -37G 37G -37A -378 -May2 -May3 12/1/2007 12/2/2007 12/312007 12/4/2007 12/5/2007 12/6/2007 12/7/2007 12/8/2007 12/9/2007 12/10/2007 0:00 0:00 0:00 0:00 0:00 0:00 0:00 0:00 0:00 0:00 Figure 6 Stages for December 2007 event. Note the obvious data errors in station 37G. King County II December 20 I 0 Iii ll . ' I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project ,i----------~--/-~---- 8 +------------~'~---------------------l . ...,y:::::~--:./ ~, 7~_.,,-_=-~/.2· '::::__~--,~~~s,c;-~~~~~~---~ 6 5 4 +----------------------------------~ 3·1------------------------- 2·1------------------------------------1 01-----------------------------~------1 1/6/2009 11612009 1/712009 117/2009 118/2009 1/8/2009 1/9/2009 1/9/2009 1/10/2009 1/10/2009 1111/2009 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Figure 7 Stages for Janu·ary 2009 event. Note the missing data for 37G. ·-·37G -37A -376 -May2 -May3 King County 12 December 20 JO Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project In lieu of investigating Anchor's approach on using a subset of data and estimate an independent peak flow for 37b, a moderately different method was performed but for preliminary review adequate for comparison to Anchor's approach. Peak daily flow rates (based on mean-hourly) were assembled from November l, 1998 through February 5, 2009 to be similar to Anchor absolute start and end dates-Ten plus years of data were used, and any days with missing data in either gauge were disregarded for this analysis. Then a robust regression (LOWESS) was performed on the entire set of peak daily data (subsequently, the same date ranges were used as in Anchor-the LOWESS results remained the same). In short, the LOWESS regression provides a sophisticated method for performing regressions applicable for linear and non-linear data making it not necessary to separate high and low storm events (Helsel and Hirsch, 2002). In addition to estimating the most likely value for 378, secondary regressions were perfom1ed on the positive and negative residuals of the primary regression to estimate a range of possible values based on the primary regression (Figure 8). 250 200 fil ~ 150 >, 100 100 LOWESS Regression plot f=0.25 200 300 x-Values 400 0 500 Simulated y-Values using LOWESS Regression 0 600 O Observed -Regression Upper/Lower 350-~~~~~~~~~--------~~~ 300 250 ~ 200 iii ~ 150 >, 100 50 o 7.3 7.315 7.32 7.33 Sequence Index (e.g. datenum) 7.34 X 10' Jan 2009 0 Observed -Simulated Lower Upper Figure 8 Robust Regression (LOWESS-Locally weighted scatter plot smoothing) on Daily Peak Flow Rates from 11/1/1998 through 2/5/2009. X-axis= 37A, Y-axis= 37B. Lower graph is a simulation of 37B using the regression and observed with time on the x-axis, and flow rate on the y-axis. Results from the regressions estimates peak daily flows at 378 to be 233-cfs (with a possible range of 198 cfs to 260 cfs) for December 2007 (Figure 9) and 272-cfs (with a possible range of 218 cfs to 310 cfs) for January 2009 (Figure l 0). Notably, this revised estimate more closely King County /3 December 20 I 0 I fi ti I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project matches the critical shear stress presented in the sediment transport study based on observed data. Additionally, performing the same analysis but not including data after January 13, 2006, the flow estimates at 378 are estimated to be 240 cfs and 280 cfs (rounding to the nearest l O cfs) for the 2007 and 2009 events. These are based on linear extrapolation of the LO WESS regression results since the magnitude of the peaks for the 2007 and 2009 events did not exist in the reduced dataset. Comparing the simulated flow rates using the robust regression to observed at gauging station 378, there are good correlations, r-square's, and slope's when using all data greater than 100 cfs and for data greater than l 00 cfs but excluding gauge records after January 13, 2006 (Table 5). A perfect fit would have a coefficient of 1.0 for each of those statistics and an intercept ofO.O. As such, the robust regression slightly under predicts observed. Table 5 Accuracy of robust regression for simulated versus observed for gauging station 378 using linear regression statistics, with observed on the x-axis for slope. Intercept Dataset Pearson r~square Slope All Data greater than 100 cfs 0.87 0.75 0.91 Greater than 100 cfs and excludes data after 1/13/2006 0.88 0.78 0.82 700 ·,---------------------------, 600 -t---------------------------------l ;F 400 +------------1------\------------1 .e. ~ • £_ 300 •------------, 100 ob===$==~~=---------~.:::'.J (cfs) 10.1 14.8 --o--37a-obs ~37b-sim • a· Lower -a· Upper --+-37b-obs 11/29/2007 11/30/2007 12/1/2007 12/2/2007 12/3/2007 12/4/2007 1215/2007 12/612007 1217/2007 Time (Dally) Figure 9 December 2007 Hydrograph of event King County 14 December 2010 Hydraulic and Hydro logic Analyses of the May Creek Channel Restoration Project 700 ,---------------------------, 600 1--- 500 200·-- 0+---~------~-----~-----------1 --0--37a-obs --o-37b-sim " a• Lower " C -Upper ~37b-obs 1/4/2009 1/5/2009 1/6/2009 1/7/2009 1/8/2009 1/9/2009 1/10/2009 1/11/2009 1/12/2009 Time (Dally) Figure 10 January 2009 Hydrograph of event It is worth noting that although it was discussed previously about the faster response for drainages below 378, no effort was made on a storm event basis to match up peaks that might have shifts within the same day; which is similar to the method previously done by the sediment study. One other comparison was performed using the HEC-RAS model developed for this project. At the May2 station, it was noted in the May Creek Sediment Transport Study, that the model was estimating approximately I-ft higher than observed after calibration. This was based on the flow rate of 340+ cfs for those two storm events. An attempt was made to reconcile where the monitoring stations were in the HEC-RAS model and known stations and locations in the ravine. Stationing between the HEC-RAS model and assumed known locations of the gauging did not reconcile; thus, matching up where the documented elevations are at the study sites and cross- sections in the model was not possible at this time. 2.4.4 illlodeD VaD6da1tio011 Edge of water was surveyed on two different days, January 8, 20 IO and January 22, 20 I 0. The January 8 survey was preceded by a small storm on January 5 cresting at 42 cfs as estimated at 148'h Ave SE bridge (KC Gauge 37G). Flows computed from the gauge during the survey on January 8 were approximately 29 cfs. The second survey occurred after a larger storm that began to recede January 16. The peak flow rate using the same stream flow gauge for that event was estimated to be 66 cfs. During the January 22 survey of edge of water, flows were estimated to have receded to a flow rate of 13 cfs as measured at KC gauge 37G (see Figure 12). King County 15 December 20 I 0 fj i fl I I I I I I I I i I • I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Survey data for the January 8 event were transposed to the nearest cross-sections (RM 4.8612 and 4 .8285) just downstream of Parcel #0223059005 footbridge and the January 22 survey work was taken upstream of the Parcel #0223059005 footbridge (see Figure 11 and Table 6 below for more detai l). Figure 11 Edge of water survey shown in light blu e lines. Table 6 Water surface observations, elevations in NA VD88. 4 .992552 1/22 4.988154 1/22 4 .9749 1/22 4.949 1/22 4.937 1/22 King County 314.27 314.35 314.08 314.17 313 .8 5 314.20 314.04 314.14 314.14 16 314.06 314.20 314.20 314.11 314.16 13 cfs 13 cfs 13 cfs 13 cfs 13 cfs 313.00 -1.06 312.99 -1.21 312.98 -1.22 312.94 -1.17 312.91 -1.25 D ecember 20 I 0 Hydraulic and Hydrologic Analyses of th e May Creek Channel Restoration Project 4.868 3/30 313.541 40 cfs 313.60 +0.06 4.612 3/30 313.971 48 cfs 313.47 -0.50 4.455 3/30 312.041 48 cfs 311.89 -0.15 1Elevation is based on tape down from top of footbridge. King County 17 December 20 I 0 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydro logic Analyses of the May Creek Channel Restoration Project 70 60 · 50 . :E' 40 ~ . GJ ~ "' a: ;i 30 0 u: 20 . +++Ill 10 0 >-> >-> .._ .._ >-> N >-> >-> >-> .._ .._ .._ w .. u, """ Htittt >-> >-> >-> .._ .._ .._ a, -.J 00 >-> .._ "' • """ I l\iilil mm >-> >-> >-> >-> >-> >-> >-> >-> >-> >-> >-> >-> >-> .._ .._ .._ .._ ......................................... .._ .._ .._ .._ >-> >-> >-> >-> >-> >-> >-> >-> >-> >-> N N N 0 >-> N w .. u, a, -.J 00 "' 0 >-> N Date/Time Figure 12 January 2010 Hydrograph for King County Gauge 37G (148th Bridge) King County 18 >-> >-> >-> >-> >-> >-> >-> >-> >-> .._ .._ .._ .._ .._ .._ .._ .._ .._ N N N N N N N w w w .. u, a, -.J 00 "' 0 >-> December 2010 Hydraulic and Hydro logic Analyses of the May Creek Channel Restoration Project Reviewing the surveyed water surface elevations shows that for those two dates, the elevations are virtually the same with the exception of the lower most point a half foot lower (associated with the 29 cfs date) than the rest. This does present an inconsistency between the calculated flow rates and expected water surface elevations. With flow rates on January 22 Jess than half of what was estimated for January 8, one would expect the water surface elevations to be lower on January 22, when in fact they appear the same or higher with half the associated flow rate. May Creek Exisiting Condition NAVD88 Plan: Scenario 1: KC Existing with Sediment v4 3/24/2010 310 24500 25000 25500 26000 26500 Main Channel OiS:ance (ft) Figure 13 Profile of observed water surface elevations for January 8 (downstream of footbridge) & 22 (upstream of footbridge) with left and right bank elevations (LOB, ROB) plotted. In addition, in the area where edge of water was taken, overbank ground elevations are lower than bank elevations effectively creating a bowl outside the channel. This is consistent for about 570 feet (RM 4.88 through 4.99). The observed edge of water was either very near bank elevations (i.e. depressional area filled with water) or up to a half foot above assumed bank elevations (see Figure 14). Given the combined circumstances of inconsistent water surface elevations relative to flow rates, and the overbank depressional areas, conveyance out of bank in the pastures likely will behave in a couple of different fashions. When flows are initially going over bank, the flow pathways will act like a branch in the stream with its own water surface profile until it rejoins the mainstem. Then as flooding waters increase, the whole valley acts as one conveyance. As the storm recedes, the overbank flooding areas begin to behave like a slow draining lake (see Figure 15). Each of these conditions has a different hydraulic characteristic that may yield these inconsistent out of bank water surfaces for a given estimated flow rate. King County 19 December 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I g 6 ,, j w Hy dra ulic and Hy drologic A nalyses of th e May Creek Channel Restoration P roject 1\11a y Creek E"x is ttin g Conditi on NA VD8 8 Plan : Sc enari o 1: KC Ex is ting w i th Se di ment v4 3/24/20 10 R S=4 .974 923 -----------.ass----------- 0 ----.oss ----·1.....---~ 320 -----,--1----5 Legend 3 18 3 16 3 14 312 200 300 4 00 Station (fl ) 4 6 WS 4 0 cfs 500 600 Ground • Bank Sta OWS40 cfs Figure 14 Example of cross-section where water surface elevation is same elevation as bank elevation (RM 4.974). Obstruction in cross-section is representative of dense canary reed grass on the banks. King County 20 December 2010 Hydraulic and Hydrologic Analyses of th e May Creek Channel Res toration Project Figure 15 Example of overbank flooding slowly draining back into channel after a sto rm from 7 da ys prior (with some minor precipitation 4 days prior). Photo taken 3/19/2 010. King County 21 December 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydro logic Analyses of the May Creek Channel Restoration Project January 14, 2010 Water Surface Observation A second observation of water surface was made during the larger storm event between the two survey dates on January 14, 2010 1:00 pm, at Parcel #0223059005 footbridge (tape down from top of bridge was used). Using the gauged flow rate at 148 1h Ave SE bridge of64 cfs, the water surface profile was within a two tenths ofa foot to observed (see Figure 16). May Creek Exisiting Condition NAVD88 Plan: Scenario 1: KC Existing with Sediment \4 4/1/2010 l<-------------MayCreekMainS:em ____________ _,, 320 319 318 ! I -+-· ··········I Legend I I I I I I I I I 317 ' : ' 316 -~ 315 i •- 314 r-....: ' 313 Main Channel DiS:ance (ft) Figure 16 Observed water surface elevation for January 14, 2010 at 64 cfs at Parcel #0223059005 footbridge King County 22 December 20 JO Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project illiarclh 30, 20110 Olll>seD"Ved Water Surface Elevations In an attempt to capture water surface elevations for smaller storm events, another site visit was conducted. Water surface elevations were obtained by taping down from top of bridge. Additionally, flow rates were estimated using standard methods and velocity meters at each water surface observation point. Observations were made at three locations, ! 48'h Ave SE bridge, McFarland footbridge, and parcel #0223059005 footbridge with their respective estimated flow rates of 45 cfs (poor quality), 48 cfs (good quality), and 40 cfs (good quality). Long Marsh creek enters in upstream of the McFarland footbridge, hence the increase in flows at that measurement. Using these field measured flow rates, model accuracy validates with good accuracy with the greatest error equal to 0.50 feet. A water surface profile and observed water surface elevations is shown in Figure 17 below, and previously in Table 6. May Creek Exisiting Condition NAVD88 Plan: Scenario 1: KC Existing with Sediment \4 4/1/2010 MayCreek Main&em ,20,-~~~~~~~~--,-~~~~-'--~~~~~~~~~~--,-~~~~~-1,--,---,-~ Legend € i 310 w --------·----·-.• ---!---~---j---+-+----f-+---- I --I __ , __ L_ Main Channel Di Sance (ft ,-1- I I __ l_ j I L I I i _._L_ WS 48 cfs Ground i --- l LOB ROB OWS 46 cfs Figure 17 Observed water surface elevation for March 30, 2010 at 48 cfs at three bridges. 2.4.4.i Validallio1111 S11J1mmary This validation shows that the model under predicts water surface elevations for lower flows in the Valley floor anywhere from 0.06 feet to 1.3 feet (assuming calculated stream flows are accurate, but appear suspect) with most of the differences in the range of 1.0 feet and has better accuracy with higher flows ( e.g. 48 and 64 cfs water surface observation). One hypothesis has been presented to partially account for the discrepancies, however there are multiple other plausible causes for the elevated water surfaces for low flows: some of which might be, error in gauge flow estimates at 37G, or unaccounted for choke points in the channel. At present, assuming the flow rate estimates are correct, it is very unlikely that water surface elevations King County 23 December 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project could be as high as surveyed. To reproduce those elevations for those low flow rates, the McFarland footbridge would have to be nearly completely damned to backwater upstream that high. While it is not known if this may have happened, it again seems unlikely. Therefore, while the accuracy of the survey data is not in question, the combination of assumed accuracy in flow rates and the edge of water survey in flooded conditions appear to represent a set of conditions neither characterized in the model configurations nor explainable in their contradictions. Therefore those two dates of observations should not be considered part of the validation. Conversely, model accuracy seems to be quite good for larger storms with error less than or equal to 0.50 feet. However, further model validation is still being pursued at this time targeting storms in the range of 10 to 20 cfs. King County 24 December 20 I 0 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Hydraulic scenarios were designed with changes in channel geometry representative to the three proposed channel improvements: I) removal of choking vegetation points, 2) removal of choking vegetation points with increased sediment removal to an elevation of 308 feet, and 3) removal of choking vegetation points with some sediment removal to an elevation of 309 feet. 3.11.11 illlodlel Geomeil:D1f Scenarios were designed to characterize existing and proposed conditions in the valley. The first scenario includes characterizing existing conditions, and three other scenarios were designed to evaluate increasing levels of channel modification to address the objectives. The naming of the scenarios are representative of the stepwise process of developing the geometry files to get from one scenario to the next in HEC-RAS rather than suggesting that multiple additional scenarios were evaluated but not presented in this report. Scenario I: Existing conditions Survey work done in January 2010 included two channel bottom elevations: on top of soft sediment, and harder substrate assumed to be the more historical channel bottom. Existing conditions is meant to represent current channel geometry with channel bottom defined as on top of soft sediment. King County 25 December 20 I 0 I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Proiect Scenario 7: Removal of vegetation choke points This scenario represents enhancements to the channel conveyance capacity by assuming Reed Canary grass is removed from the channel and banks, and Willow root systems are removed from the channel. The assumed channel bottom for this scenario and subsequent scenarios are based on the harder substrate sediment. This is based on the calculation of critical shear stress of silts in the channel and steam competency to mobilize the silts (see Section 4.0). May Creek Exisitng Condition NAVD88 Plan: 1) KC_SCN_ 1 3/2612010 2) KC_SCN_7 3126/2010 "' --- Main Channel DI Sance (ft) Figure 18 Scenario 7 longitudinal profile in study area. The black line is channel bottom using top of sediment (used in Scenario 1) and fuschia color line is profile of channel bottom to firm sediment. King County 26 December 20 I 0 Hydraulic and Hydro logic Analyses of the May Creek Channel Restoration Project Scenario 8: Removal of vegetation choke points and increased sediment removal This is the most aggressive scenario with sediment removal assumed to occur between just downstream of !48'h Ave SE bridge to the 125 ft upstream of McFarland footbridge-in total approximately I 025 ft at an elevation of 308 ft. The elevation of 308 ft was selected based on the apparent historical channel bottom at 148'h Avenue SE bridge crossing. May Creek Exisiting Condition NAVD88 Plan: 1) KC_SCN_ 1 3/25/2010 2) KC_SCN_S 3/25/2010 MayCreekMa(maem -----~-L_:--·~:i 1 ll ;f=--L:t-~ -_--~=:~t-1--:=1rn=r:~:-·-''''"' 315 .•• : ~~ --: .·. f 1 r-r-· ! l :-:· -·:-:: -1: I L; '~ c=i ---: opof~~:'m'" J----l---'T" '! _µ --i i \"1---''-'--++--- 23400 23600 23800 24000 24200 24400 24600 Main Channel Dlfanco (ft} Figure 19 Scenario 8 showing existing conditions and proposed profile after sediment removal (308 ft) and flushing of silts. King County 27 December 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Scenario 9: Removal of vegetation choke points and some sediment removal Approximately 518 ft of sediment (125 ft upstream, 393 ft downstream) of McFarland footbridge is assumed to be removed to an elevation of 309 ft. This elevation was selected to be similar to historical channel bottom elevations leading down to 148 1h A venue SE bridge crossing and to evaluate an intermediate alternative. May Creek Exisiting Condlllon NAVD88 Plan: 1) KC_SCN_ 1 3/25/2010 2) KC_SCN_9 3/25/2010 315 --- 23400 23600 23800 24000 24200 24400 24600 Main Channel OiSance (ft) Figure 20 Scenario 9 showing existing conditions and proposed profile after sediment removal (309 ft) and flushing of silts. 3.1.2 Typical Channel Cross-Section Typical Channel Cross-section within the sediment removal segments was simplified for this study to assume existing channel geometry with the bottom dropped to the proposed elevation. In final design, sections where excavation exceed 2 feet below top of sediment, channel banks will be given side slopes to prevent bank sloughing. This simplification represents a conservative side of expected as-built conditions given the addition of side slopes will slightly increase channel capacity. King County 28 December 20 IO Hydraulic and Hydro logic Analyses of the May Creek Channel Restoration Project May Creek Exisiting Condition NAVD88 Plan: 1) KC_SCN_ 1 2) KC_SCN_B RS= 4.622613 ---···---' ~, •--~-tt---------~-~rr:-·1-~--··· · .. _! t·· -1-· Legend -----. --: · 1-r+I ······· -----~~-----. . .... ' ·-··---,--·1= G"'und-KC SCN 8 ------~ --.;.... 1 ·-..l...-..-t,-~-----· +-,' ___ _J_ · .. ' 0 -- I I 1 1 ! bank Sta ·KC_SCN_t , ____ ....j.__.....,__+! _:·--1-'~=.---~' .,. I i ' G"'und • KC_SCN_ 1 314~· o · I I -. . ' i i . I ! ! ' aaak Sta· KC_SCN_ 1 ··-• . -. -I' .. . . -i:·.t .I,. -t -~---: 1' -·-------·-:·:-~ r----------W/: ! 1 i · 1--:-i i ,,, -----"---: 1+rt+~ > -F H+ ~ ; 1 • 310 ------__ Ji-'.L~)-----.1.1--------i I· ---~ · : j-:-: r -11 1 --; C-rr~ 308 -------f---..-r 1 -+-1 -·· ---- 1 1 I , . . 1 rr- ___ :· .. : ..... :. i-r' f-J-:: ·--~--1 ·rr=~r::~----·-;-~:·· 200 250 300 350 Station (ft) Figure 21 Typical Channel Geometry of existing (black line) and proposed (fuschia line). King County 29 December 20 I 0 I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project 4 .. 0.. SEDIMENT TRANSPORT A particle size distribution was not performed for stream reaches in the valley floor; however, during field visits, it was noted that much of the channel bottom is extremely soft-in some places up to 3 feet of muck. Given the amount of bank vegetation and slow velocities, the soft sediments arc likely made of up fine silts and organic matter from decaying vegetation. Given this condition, the particle size distribution (D 50 ) used for incipient motion in the valley channel was assumed to be 0.10 mm diameter (0.000328 ft). Aside from the percent of organic matter and possible colloidal conditions, incipient motion was calculated assuming the sediment is non- cohesive in nature and made up of mostly silt. While Shield's curve is nearly constant for substrate sizes larger than 5 mm (Re* -400), it varies with smaller particle sizes. Thus it was necessary to compute the particle Reynolds number to obtain the Shields value (Guo 2002). Using a particle diameter ofO.l mm, translates to a Re* approximately equal to I.I, and Shields number of approximately 0.10 (Figure 22). Hence, the computed critical shear stress of less than 0.0 I psf is estimated for silty fines. Guo-Shields Empirical 1 ' 0.1 0.01 0.1 1 10 100 Re* Figure 22 Guo-Shields Empirical Curve In Hee-RAS, the shear stress is computed with the following formula: r=}'RS, 1000 I where R is the hydraulic radius, and S is the energy slope. I I I I King County 30 December 20 I 0 Hydraulic and Hydro logic Analyses of the May Creek Channel Restoration Project Summary of results include assessments of existing and proposed channel capacities, changes in flood frequencies and durations, stream competency to mobilize fines, and changes in erosion in the ravine. Reviewing existing conditions, it is apparent where hydraulic controls are located in the system (based on available survey data). During mean annual flows (8.6 cfs through the study area), control points are vegetation choking points in the wetland downstream of l 48'h Ave SE bridge and mildly so upstream of 1481h and gravel deposition where Long Marsh enters into May Creek at approximately river mile 4.64, just upstream of a footbridge. This high point of gravels controls the water surface elevation upstream approximately for 2000 feet to a footbridge located approximately at river mile 5.04 (Figure 23). Similarly for higher flows (e.g. 1 year event), Long Marsh again controls water surfaces upstream for the same reach length. May Creek Exisillng Condition NAVOS8 Plan: Scenario 1: KC Exis~ng with Sediment IA 4/1/2010 23000 28000 Main Channel a11ance (ft) Figure 23 Scenario 1 (existing conditions) water surface profile for mean annual (filled in water surface) and Conditions Report 1 year event (blue line with symbols). However, downstream of l 48'h model runs show a convergence of water surfaces for the same flow rates for pre (Scenario 1) and post (Scenario 8) project based on the transition from a valley to a ravine. This abrupt natural constriction changing from open wetland on valley floor to a well defined channel entering into the ravine become more controlling the larger the storm event. While water surface elevations may be lower for Scenario 8 in the wetland for the same flow rate, water surface elevations approaching l 46'h Ave bridge converge to the same elevation (Figure 24 ). King County 31 December 20 I 0 I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project May Creek Exisillng Condition NAVD88 Plan: 1) KC_SCN_8 4/22/2010 2) KC_SCN_ 1 4/22/2010 "========;=====;:='"~·~,c~-~';'-"'~'""""""•c:==::;::==::::;:==::::;:=:;===:'.lr---.--cc=--,1 317 -1-Legend 3'6 WS 1-yr Baan Plan -KC_SCN_B WS 1-yr Ba!ln Plan -KC_SCN_ 1 "'1~=::===i===1====rw=2=1:::1~E~=E~=t::f::'.::~L-----"G""m~"""'-'--_J1 ,,,aJ----,---1---+-----1 309,-~, 30, I I 307 23000 24000 25000 26000 Main Channel llotance (ft) Figure 24 Water surface profiles for the I-year (Conditions Report) for Scenario I and 8. Red circle highlights the convergence of profiles at 146th Ave bridge. Secondarily, removal of vegetation choke points in the wetland show a few tenths change in water surface, but given the model accuracy and very small amount of lost storage, this natural land form downstream of the proposed restoration channel activities will greatly control potential changes in erosion in the ravine, and less control from the bridge at 146 Avenue SE. In the following sections, three scenarios (plus existing conditions) were focused on for evaluations: o Scenario I-existing conditions, o Scenario 7-removal of vegetation choke points, o Scenario 8-removal of vegetation choke points with increased sediment removal, and o Scenario 9-removal of vegetation choke points with some amounts of sediment removal. As previously mentioned there are three main control points in the system under existing conditions: 1) the natural transition from valley to a ravine, 2) vegetation choking the channel downstream and upstream of 148 1h Ave. SE, and 3) sediment depositions upstream of 148'h to the confluence of Long Marsh Creek. Each of the proposed scenarios improve in channel conveyance to varying degrees of success with Scenario 8 resulting with the ability to maintain waters in channel up to approximately 50 cfs for properties upstream of 148 1h Ave SE. King County 32 December 20 I 0 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Estimated hydraulics for Scenario 8 elucidate that the control points effectively move down to the transition of the wetland to a channel entering the ravine for lower flows (Figure 25) and for high, infrequent flows (Figure 26). This characteristic supports the results of no increases in erosive flows to the ravine before/after the proposed project for the same flow rates. May Creek Exisitlng Condition NAVD88 Plan: 1) KC_SCN_8 4/22/2010 2) KC_SCN_ 1 4122'2010 Main Channel Dl!ilance ffll Figure 25 Water surface profiles at 50 cfs for Scenario I and Scenario 8. King County 33 December 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project May Creek Exis!ling Condition NAVD88 Plan: 1) KC_SCN_8 4/2212010 2) KC_SCN_ 1 4/2212010 1---------------MayCreekMaln!l.em---------------.~--~~-~ 316 -------t----~• ~-l--1--11---____ [ _ _L_. I _:...:=:..::..::..:J:==:;::..:±=====:, WS 100-y~::~:C_SCN_8 _L •, WS 100-yrwr.-KC_SCN_1 [:;,=· bj ;J-~~1 r=f~-; Go,od 3140---- Main Channel Daance Figure 26 Water surface profiles for the JOO year flood event for Scenario I and 8. King County 34 December 20 I 0 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Capacity at the bridge located at 146 1h Ave SE show that the I 00-year (Conditions Report) flow rate does go overbank (left side looking downstream) under both existing and proposed conditions and at the same elevation. Again it is worth noting that under the proposed project, the magnitude of the I 00 year return period decreases, water surface elevations post project will be less (Figure 27). Similarly, the bridge downstream at 143rd Ave SE shows to have capacity to pass the 100-year pre and post project (Figure 28) as well. It is worth noting that the bridge geometry used for 143'd Ave SE is based on previously existing geometry from the previous HEC-RAS model. A survey crew is scheduled to resurvey this bridge and confirm existing geometry from previous modeling efforts. May Creek Exisiting Condition NAVD88 Plan: 1) KC_S0>1_8 4/22/2010 2) KC_SCN_1 4/22/2010 RS= 4.28 BR Bridge #2 146TH AVENUE (RM 4.280) I ' .08 ·1 .04 I .08 I I -··------ 1 I . --·--. -·----+--'-+-+---1-------t Legend I I I ! I i -' 320 I j I 11v I WS 100-yrcur. -KC_SCN_B 4 I t lwS 100-yrcur. -KC_SCN_1 -1 ' ---t ~ -r --. -'" ----.. - .. j j I t · f --, .. --f Ground --1 ----0 I I Bank Sta -1 --1 lkr. -. i I ' j l"" ---~ --. -I . ./ -.. ....... I I I ' ' ' ' 315 -i-i~ ~ _J_./i --1-1 I --j --1---J --·---I , ..... ···-·I -I g i-t~ i -~ - j .,.,. . ---·-. I • ! .. L. -" --·---· 6 ----i j --. . .. ) _(_ L-1 ~::i...= ·-;-.... .• ·+ .,, I---------:------T~ . w ----+ ' --~-·f r -1 -. ··•--·- -~- I I i ' I 310 -~-----l I I i ' ' ' I I I I ! ! I ! I I I I I I I I I ! L 11 i --c_ ------------+-+-_!_ _ --=-:~=t L ·----1 ---" .. , [ ........ _), ___ 305 I I I . =---t-t-=----•••"'"· . j_ ~--..... _ -~=r--=---=--::-: ·---[--1-J__I_ __ ~--i- --i--t+···· __ ,_.....,.... __ ,_ I I 100 200 300 400 Station (ft) Figure 27 Water surface elevations (Scenario 1 and 8) for the 100 year (Conditions Report) at the 146th Ave bridge. King County 35 December 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project May Creek Exisiting Conditioo NAVD88 Plan: 1) KC_S0,_8 412212010 2) KC_SCN_1 412212010 RS=4.114 BR Bridge #1 143RDAVENUE (RM 4.118) .OB •I . I-== os===:-1 325 ---+---_; __ .. o-Legend ------4 -----I --:-t I ' WS 100-yrcur. -KC_SCN_8 I ' WS 100-yr cur. -KC_SCN_ 1 __ l_ I ' I ' ' ----r-Gro.und ' ' 320 ' : r /1 lneff ' I I 0 I Bank Sta ' i I I ' i'-.... I ' I ' 315 ~ ( I g I 6 I I /' ~ ~ !l T . I . " '·-·--I .• . I .. ., I w I I _/ " ,_ 310 I I ----\· I . . . -• ··----•· ·1·-... -r . ·-·- l . ·-. -.................. 1 .............. -·-·"l --·--1· .....,._ ---·-.. i -. I I I '-'" i ... ' --~ -· -. ·--~ 1-•. . j . .. I i ' ' 305 . J ' I I -! ' ,·-T_ I -·-·-- I : --" ·····" , .. -....... , -~ .. . I -,' -· -I ... I I ' I__ 1---T .. ••••.•.• ..j... .•• --' ------t---,-· 300 0 100 200 300 400 Station {ft) Figure 28 Water surface elevations for the 100 year return period (Current Conditions) at bridge crossing at 143rd Avenue SE for Scenario 1 and 8. King County 36 December 20 I 0 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Hydraulic analyses using HEC-RAS estimate that Scenario 1 (i.e. existing conditions) flow rates as low as mean annual (8.6 cfs) over top banks inundating pasture lands (Figure 29). In fact, channel capacity estimates for a few sections show that flows can go out of bank at rates as low as 6 cfs for existing conditions (Figure 30) while Scenario 8 (later in this section) keeps flows in channel up to 50 cfs. Thus calculations for evaluating improved conditions in May Valley are based on this threshold of flows between 6 and 50 cfs, such that any improved conveyance capacity will reduce the frequency and duration of minor storm events flowing out of bank. May Creek Exlsiting Condnion NA"1:188 Pl.,; Scerwirlo 1; KC E.,dng with Sediment"' 411/2010 4.948111 /Web 4.974923 4.992552 G"'und 01nkS111 ,,__~--11 #022305900 McFarland Footbridge 148 1h Ave SE Bridge Figure 29 Perspective plot for Scenario I (Existing Conditions) mean annual !low rate (8.6 cfs at 148th Street) King County 37 December 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I g 6 1 w 320 319 318 317 316 315 Hydraulic and Hydrologic Analyses qf the May Creek Channel Restoration Project May Creek Exisiting Condition NAVD88 Plan: Scenario 1: KC Existing with Sediment v4 4/1/2010 io----------------MayCreekMainstem ---------------~ r· i ~-- --'-- I .I - ... ' ' -r---\ ....... T +~ .... ----.. ·-------f---+-----1 ' I I ' ' --. -+-. .... 1~-- I ' I i I "'"' J '"'"'! Main Channel [)stance (fl) ~-----,, Legend ws mean annual Ground LOB ROB Figure 30 Longitudinal plot for Scenario I (Existing Conditions) water surface profile for mean annual flow rate. King County 38 December 20 I 0 Hydraulic and Hydro logic Analyses of the May Creek Channel Restoration Project Scenario 7 With complete removal of encroaching canary reed grass and Willow trees, flows are kept in bank between 148 1h Ave SE and at the footbridge just downstream of Long Marsh Creek (Figure 31 ). However, this is predicated on the fact that all the silty fines are flushed out of the system. Without that successful element, in-channel capacity will be greatly reduced and more representative of existing conditions (Figure 32). One of the most effective choke points to be removed is just downstream of 148 1h Ave SE. The combination of canary reed grass and Willow trees significantly reduce potential channel capacity at this location and a few others further downstream. t.tiyCreekEJdsltmgCondit;onNA',,088 Plan: 1)KC_SCN_7 411/2010 2JKC_SCN_1 41112010 4.949111 4.H2552 logor>d In Cnnnl 50 cla-KC SCN In CMnl 50 <111-KC.SCN_ Clr<>und BorlkSt1 loeff 4-~~~-11 #022305900 McFarland Footbridge 148 1h Ave SE Bridge Figure 31 Perspective plot for Scenario I and 7 (vegetation removal) 50 cfs at 148th Street. Light blue are for existing conditions while dark blue are for Scenario 7. King County 39 December 20 I 0 I I I I I I Ii ti I I I I D I - ; 9 § ~ .... 0 f <:,- ~ "' 0 -0 --------- .,, cF.," C ;;i ... .... ~ " ;; ., ~ C ., i.l' " " 'C ., = ::, " " -u, = " .:, o' ., CJ) g = " ~- " = Q. .... --.. -l!!!!!!!'J --- <: • 5 " " • s .. " ~ • , 0 • ~ w NO w Elevaticn (ft) w w w ~I ' ~ i ""\ ~ :, ' : ; T _4.265343 Dcwnstream, of.Ro. _4.200185 KC_Survey_year ... :;: 0 '" ti "' • "' _4.319"'9 ~ ~ 1,5.3531.!36.KC,· .. -Sui:v.eJ.Y? o ,-4.378325 l 0 ::_4.411003_~~ -- N ~ 0 0 0 N i,l 0 0 N m 0 0 0 _4.432545.KC,Sumiy_ymr. -:4~455.Blictie:#3__:!~hL__ _';; _4-482002 KC_Survey_year.2>10 __ A.SOZ641---J __ -,,.- _4.53227A ----C-:562:ooa i i _4.600~_ -4.640315_ --;. --, 1- _4.100732-KC.suJ~e8""r:201Q- _4J.495H.KC.Su~ey.)'mr..a>lO --1·-··· ' ___ ; .......... 1--.-f ·-"""" ·-- ,-4.ZBB456 KC.Survey.year.alJO.(sh A828f.66J<C.S~ey.Jeer:·2J1Ji(s~ !~:r :_ .. i-.r-·_ .. ___ ·- ••• , •• ~?i~-KC.Su~~,Y~(~ -. "· --+---1 :..4.969124--......l._=t---- -4.992552 otak._xs]33s, ____ _ ' I L_ . 5.038938.otak xs.7575 ~ --r -_j_ L .j. ~ 15.097003 Otak. KSJW.5 0 ' ' o SJ:1)564 otak XS 8005:------t:-7' I ' l . _, I I _ ~ 0 ii! " ~ --··---1 1 m .. 00 s· <O 0 0 0 0. g ~-I I~ i'Ft----> ' i------~ ~ _;...__ -·------ii: CD • ' ~ -~-----' l , 0 ·,=--:~ ~~:,; -·-lo (J) kl--. -0 z I -... -\- " ~ 0 1LI ---11~ ;,; 0 I 5.185707.ota~ x,; 831 1 b 5 228003 Otak. XS 8545 -• - ~ J 5.2llffi8 Las.I XS_d_Otak Work.otak xs Ba. •. g -~--.=="'====_ca='c_a=;=;~ ~ ~ (J) " z I 5" 5' " " " ~ ~ !; Qt~ , a. r ;;, fjillo a :g ~ ,ll ~ § " 0 • , ro ro f,f , 0 ~ ~ ~ ~ " " ," ," "' "' ,'). ,2 " - - $ l " :, "-. $ !:;- " ~ ri' ,. :, " "' "' Cs ~ :;,. " ~ "' ;? "' """ 9 " :, :, ~ "' " "' c il 5· :, :ii "'· " !:'. Hydraulic and Hydro/ogic Analyses of the May Creek Channel Restoration Project With only a water surface reduction of half a foot through the study area, conditions upstream of Long Marsh are clearly unimproved given flooding still occurs at the mean annual flow rate (Figure 39). Furthermore, storm flows may begin to overtop downstream of Long Marsh depending on the magnitude of the event again not meeting project goals. MayCraekExl1rtingC0nditlonNAVOB8 Plan: 1)KC_SCN_7 41112010 2)KC_SCN_1 41112010 4~0111 Smeanunuol•KC SCN mHn unual -KC_SOI_ Gn,uno B1i*S1a . ., ......... ~---11 #022305900 McFarland Footbridge 148 1h Ave SE Bridge Figure 33 Perspective plot comparing Scenario 1 and 7 under mean annual now rates King County 41 December 20 I 0 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Scenario 8 Under the proposed project design, Scenario 8, with vegetation removal and sediment removal down to 308 feet for approximately 1000 feet, the conveyance capacity increases to approximately 50 cfs in the previous sections where 6 cfs would be out of bank. This improvement effectively mitigates storms near the I-year magnitude (i.e. 61 cfs). Figure 34 shows that for 50 cfs, May Creek is over bank for existing conditions in the entire project area while for Scenario 8, flows are kept in-channel until the wetland area downstream of l 48'h Ave SE (shown in dark blue). Hydraulic controls in the system coalesce down to the outlet of the wetland entering into a well defined channel leading to the ravine, with a small difference in water surfaces through the wetland area as a result of removal of vegetation choke points (Figure 35). One of the primary choke points to be removed affecting upstream of 148 1 h Ave SE is the combination of canary reed grass and clumps of Willow trees encroaching in the channel just downstream of l 48'h Ave SE-significantly reducing channel capacity. MayCreekEx,sttJngCondlUonNAVD88 Plan: 1)KC_SCN_8 41112010 2)KC_SCN_1 4/1'2010 •.949111 In Chnnl 50 d•· KC SCN 1n CMnl so ofs • ..;c_sc,.c ... 4--~---11 #022305900 McFarland Footbridge 148'h Ave SE Bridge Figure 34 Perspective plot for Scenario I and 8 overbank flooding with 50 cfs at 148th Street. Light blue areas are inundated areas for Scenario I and dark blue are Scenario 8. King County 42 December 20 I 0 Hydraulic and Hydro logic Analyses of the May Creek Channel Restoration Project May Creek Exisiting Condition NAVD88 Plan: 1) KC_SCN_ 1 4/1/2010 2) KC_SCN_S 4/1/2010 -€ Main Channel Ostance (ft) Figure 35 Water surface profile at 50 cfs for Scenario I and 8 King County 43 December 20 I 0 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project In addition to lower flows, a review of higher flows was done. Focusing on downstream of the wetland through the bridge located at 143'ct Ave SE, the same return period of flood frequency was used, but with their respective flow rates of 229 cfs (Scenario I) and 240 cfs (Scenario 8) for the 2-year return period through the ravine. There is a marginal increase in water surface elevations downstream of 146'" Ave SE of0.08 ft and diminishes to 0.05 ft at 143'd SE (Figure 36). More importantly, the velocity changes are minimal as well with 0.10 ft/sat 146'" Ave and 0.06 ft/s down at 143'ct Ave SE. This marginal change in water surface elevations and velocities are essentially within the accuracy of the model validation. Thus, no effectively apparent significant changes between existing and proposed conditions at this flood frequency. Moreover, selecting any higher flow rates will result in even less differences between pre and post conditions. May Creek Exisiting Condition NAVD88 Plan: 1) 2yrScn1 4'221'2010 2) 2yr$cn8 4/22/2010 l<--------------MayCreek Maln!tem ---;---:;-;---;---;--;---;---;--;--1~-==-~ I * i I .. I :-~-, I ·-j '"'" I : I i WS 2-year Q -2YrScn8 314 -I ~ -.}. -! WS 2-yearQ-2yrScn1 --i f -1 • l. Ground --, 1 1 r I 1-----l I I ' '" ------r----_-- 1 ' 308 304 302 I 21600 21800 22000 22200 22400 22600 22600 23000 Main Channel Dstance ft) Figure 36 Water surface elevations for the 2 year return period (229 and 240 cfs) for Scenario I and 8. King County 44 December 20 I 0 ------------------------------------------------ Hydraulic and Hydro logic Analyses of the May Creek Channel Restoration Prqject Scenario 9 The alternative scenario of removing sediment and choking vegetation to an elevation of 309 feet (Scenario 9) is less effective at keeping flows in-channel at 50 cfs through the project area (Figure 37). However flows are estimated to stay within bank between 148 1h Ave SE and at the footbridge downstream of Long March creek confluence. However, this is primarily because of the element of removing vegetation choke points and the assumed flushing of existing silts with the increased velocities. Again, convergence of the water surface profiles converge at the natural control of wetland outlet (Figure 38). It is worth noting that flows are maintained in channel through the pasture areas up to approximately 40 cfs. May Creek Ei<lsitlng Condition NAW88 Pl-,: 1) KC_SCN_9 '1112010 2) KC_SCN_ 1 ~11t.2010 Hl49111 iogond In Chnnl ~O cl•· KC SCN In Chnnl 60 er •. KC_SCN_ B1""-Sla lnoff 4-~~~~1 #022305900 McFarland Footbridge 148 1h Ave SE Bridge Figure 37 Perspective plot for Scenario I and 9 overbank nooding with 50 cfs at 148th Street. Dark blue areas are for Scenario 9, light blue are for Scenario I (existing conditions). King County 45 December 2010 I I I I I I I I I I I D I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project May Creek Exisiting Condition NAVD88 Plan: 1) KC_SCN_ 1 4/1/2010 2) KC_SCN_9 4/1/2010 300 22000 23000 24000 25000 26000 27000 Main Channel Distance (ft) Figure 38 Water surface profile at 50 cfs for Scenario I and 9. 5.2 Updated Flow Frequencies 28000 Original flood flow frequency estimates in the May Creek Current and Future Conditions Report were based on a 42 year period of record from water year 1949 through water year 1990, and a single scalar to translate SeaTac precipitation to May Valley conditions using Bulletin 17-B (USGS 1982). As previously mentioned, current hydrologic analyses include additional data through water year 2008 (18 years more data). This combined with the updated FT ABLES for existing conditions, and flow frequencies have changed since the original analysis was done in the May Creek conditions report. Frequency analysis was done for two locations in the basin, flows draining through project area to 148 1h Ave SE bridge (Figure 39) and flows down to Coal Creek Parkway. This illustrates how estimates of flood frequencies are dependant on period of record in addition to magnitude of events and any small changes in frequency estimates should be viewed with that understanding. Through the valley area, the magnitude of the 2 year flood frequency increases from 283 to 289 cfs (5 %). The increases in changes between Scenario I and Scenario 8 diminish to no change between scenarios at the 20 year event. In fact, flood events greater than the 20 year event decrease after the project. It is also worth noting that all the changes either increasing or decreasing are within the 95% confidence interval of existing conditions (Table 7). For convenience, the original May Creek Current and Future Conditions report flood frequencies are included in the table. King County 46 December 2010 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Table 7 Summary of flood frequencies for Scenario I and Scenario 8 for May Creek in the valley. Scenario 1 Scenario 8 Conditions Return Percent Report Period 17-B Upper Lower 17-B Upper Lower Difference (1995) 1.01 53 64 41 61 73 48 16% . 110 1.11 94 108 80 104 118 89 11% n/a 1.25 120 135 104 130 145 114 8% n/a 1.67 163 182 145 173 191 155 6% n/a 2 186 208 167 195 216 176 5% 165 5 283 326 252 289 329 259 2% n/a 10 351 414 307 354 412 312 1% 285 20 417 503 359 416 496 362 0% n/a 25 438 532 376 436 523 378 0% n/a 40 483 595 410 478 581 411 -1% n/a 50 504 625 426 498 609 426 -1% . 413 100 571 722 476 561 698 473 -2% 468 'Flows were interpolated and extrapolated from published 2, 10, and 100 year flow rates in the May Creek Current and Future Conditions Report. Similarly for the ravine, these changes in flood events are nearly the same. The 2 year flood event increases from 229 cfs to 240 cfs (5%). Flood frequency magnitudes decrease starting around the 20 year event. Again, this estimated change is within the 95% confidence range of existing conditions (Table 8). Table 8 Summary of flood frequencies for Scenario I and Scenario 8 for May Creek in the ravine. Scenario 1 Scenario 8 Conditions Return Percent Report Period 17-B Upper Lower 17-B Upper Lower Difference (1995) 1.01 67 81 52 78 92 62 16% 141 * 1.11 118 135 100 130 147 112 10% n/a 1.25 149 167 130 161 179 142 8% n/a 1.67 202 225 180 213 236 192 6% n/a King County 47 December 20 I 0 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydro logic Analyses of the May Creek Channel Restoration Project Scenario 1 Scenario 8 Conditions Return Percent Report Period 17-B Upper Lower 17-B Upper Lower Difference (1995) 2 229 256 206 240 266 217 5% 208 5 349 400 310 355 404 319 2% n/a 10 431 508 378 435 506 384 1% 357 20 513 618 442 512 609 446 0% n/a 25 539 654 463 537 643 466 0% n/a 40 594 731 506 590 716 507 -1% n/a 50 621 769 526 615 751 526 -1% 514* 100 704 889 588 694 864 586 -1% 582 *Flows were interpolated and extrapolated from published 2, 10, and 100 year flow rates in the May Creek Current and Future Conditions Report. Additionally with the proposed improved channel conveyance, attenuation of flows is marginally less thus slightly increasing flow frequencies on the lower end with the I year event increasing from 54 cfs to 61 cfs (Figure 40). Flow frequencies in the ravine were similarly indifferent between existing (Figure 41) conditions and proposed (Figure 42). King County 48 December 20 I 0 Hydraulic and Hydro logic Analyses of the May Creek Channel Restoration Project Scenario 1 -MVL RBO Weighted Skew (G= -0.15274) Probability Plot 10' } 1 J .. ~ ! 1 } 1 t ,;, 0 0 N N N M R1:turn li:i El<pt:'Cl.d (yeu) /cfe) !C!s) ----------------------~oo.co "' ti71 571.0-cfs 100. co 571 59:) :JO.CO ~o~ n::, 1,(),(:1) 1fl] 1!'15 438.1-ds ----·M-•M ___ H_ 2'1.CO 4)(1 H7 ~o. r:o ~ 17 1::'~, 350.9-da 10. co 1!.>l j!.,:, ·--·--·--.. -,, .. _,,_ .. ___ <D 5.CO WJ Z!lii 2 .co : ~t 186 283.5-ds "': 1.50 :,19 11,3 ;;; 1.2!.> :.'.!O 11a i l.Cl '.',.'.! " ,'l 185.9-cfs a: j ~ " , C .:i 10' =170 95%CI --Expected * Weibull D 2008 ¢ 2004 ¢ 2008 ¢ 1991 ¢ 1990 ¢ 1951 § §: iil ~ ij ~ ~ M 8 § iil 0 ~ ~ ~ :§ :g ::l N 8 "' N 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 00 Exceedance Probability Figure 39 Flow Frequencies for existing conditions using USGS 17-B methodology for flows at 148th Avenue SE (catchment MVL) King County 49 December 2010 I I I I I I I I I I I I I 11-~-~ \'"'!']-.,,.,. ... '11'"~---, ~'"T''••••t"~~=~~-,....,.......,.,..,..,.-~-...... .,~,,,_, T-~ • ~='~ ~~ ' , , I ' I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Scenario 8 -MVL RBO Weighted Skew (G= -0.12543) Probability Plot 103 ~ \;, J: J; ,. f J J; J t ii 0 :g "' :!l 0 N ..; 560.7-cfs •• -------·-----·-·--··-·--------.. ··-·--.. -........ ____ .. __ ., ___ .. __ :r--:::· --·---·--·-· 436.1-cfs,-------·----·----------,-";7",... ·-·------· .. 353.7-cfs____________________________ _ ······-·-·-···---289.4-<:fs _______________ -:;c-;',.,,t; 10' m 0 0 0 0 ~ 0 ~ 0 0 0 0 ::? m m ~ 0 0 ID 0 ~ 0 ::? ~ N m m m m ~ ID ~ ~ N 0 0 0 d d d d d 0 d d d 0 d d Exceedance Probability J 0 N ~ N 0 0 0 0 0 0 d d d R,nucn 173 E'~po>cld lye~r) ,:cf.l!i !:=fsl ~00.CO 1(10.(:0 50.CO 1,0.Cli 2.'.>.CO ::o.r:ri 10. co s .r.r1 2. co 1.1;0 l. 2C> 1. Cl 62' 51il 49ll 17tl 4:;f Hf, ======-170 95%CI --Expected * Weibull D 2ooa 0 2004 0 2008 0 1990 0 1991 0 2007 29Z 19~ 1!'19 12.!l S9 Figure 40 Flow Frequencies using USGS 17-B methodology for proposed project design (Scenario 8) for flows drainging to 148th Aveneue SE. King County 50 December 20/0 10' 10' Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Scenario 1 -CCP R100 Weighted Skew (G= -0.12501) Probability Plot -4114-gi __ ·-----·----·-----,1!<ll 348.7-cfs_,_,, ___________ ._=£ * 0 Exceeoance Probability 0 "' H<nua, 17:l r.11p~ct .. d (year) (Cf.Si tcfsJ ~DO.CO lClO. CO :.>O. CO 1,0.C(1 2~.co :<'>.CO 10. co 5.CO 2.co l.50 J.2t> l.Cl o::::::=:= 170 95%C1 --Expected * D 0 Weibull 2008 2004 ¢ 2008 ¢ 1991 ¢ 1951 ¢ 1990 Figure 41 Flow Frequencies using USGS 17-8 methodology for existing conditions at Coal Creek Parkway (catchment CCP) King County 51 December 20 I 0 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ,o' 10' "' "' "' 0 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Scenario 8 -CCP R 100 Weighted Skew (G= -0.082482) Probability Plot ,... 0 ·-·------···---693. 9-cts _________________ _ 537.1:cfs --··---·--···· 434.6-cfs ··-·--·----·-----------·-#!~~ -·----·-·-355.5-cfs ··-··------···-···--·-··--·----;-:':':;,,!; 240.3-cfs ,t'' _________ .. _ .. _____ .... _."" __ .. _____________ .. _ .. _____ r· .,,, g 0 0 0 ~ 0 " 0 0 ~ g 0 ID 0 " 0 0 "' "' ID ID ~ " N ;; 0 0 0 0 0 0 0 0 Exceedance Probability 0 ~ 0 0 0 ,! ~ N 0 N 0 0 0 0 0 0 0 0 0 0 0 0 A,nurn 173 E'xpo>cld 11,ear) icf.!) 1::.ts1 .;oo.co 1H on l(JO.t;O (i'H 716 2'0.CO 615 6)3 1,0.(;I) 59,l fi,H 25.CO ~37 5~7 ~0.r.r, 51: e>.c.< 10.CC> 4:C.!.o -119 !>. r.o :~~,'.; :;59 2.CO 24fl 2~3 l.SO ~% H5 1.2'..> : 61 l!i:l l.Cl 77 75 =178 95%CI --Expected * Weibull D 200a () 2004 () 2008 () 1991 () 1990 () 1951 Figure 42 Flow frequencies using USGS 17-B methodology for proposed project design (Scenario 8) at Coal Creek Parkway (catchment CCP). 5.3 Reduced Duration of Flood Inundation for Smaller more Frequent Events Reductions of durations in pasture flooding are quite substantive given the conveyance improvement from 6 cfs to 50 cfs. Using HSPF, a watershed model was run for a period of 60 years (water year 1949 through water year 2008) at one hour time steps for each scenario. Using the continuous output from the model, a durational analysis can be performed estimating the length of exceedances at any given threshold. It is worth noting that these analyses are a simplification of actual conditions. These results do not take into account the time it takes for the flooded pastures to recede back into the channel after a storm event, thus actual reductions in durations of inundation will be less than presented here, but for the purposes of demonstrating improvements this method is valid. Relevant for valley flooding, the two key thresholds of interest are 6 cfs and 50 cfs where flows are either out of bank or in-bank-post project. Under existing conditions, flows are forecasted to be over bank, on average, 24-percent of the time or roughly 3 months of the year. Which given the episodic nature of storms in the Pacific Northwest, and the unaccounted time for King County 52 December 20 JO Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project receding waters, this could be interpreted as multiple more months of inundation. Durations of flows flooding the pasture for the proposed design (Scenario 8), shows a significant decrease assuming flows are not out of bank until flows exceed 50 cfs. For this threshold, flooding is expected to occur, on average, 3 percent of the time per year or roughly 2 weeks (Table 9). Again, it is important to note that this does not account for time draining the pastures after an event has occurred, thus the effective reduction in pasture flooding will be less than presented here. Reductions in duration of flooding are likely to occur when storm magnitudes begin to diminish in spring and summer with peak flow rates more likely to be less than 50 cfs. While the other two scenarios are included in the durational analysis and in the table below, the threshold for over topping banks is less than 50 cfs, hence reductions of durations will be considerably less with Scenario 7 (removal of vegetation choke points) the least effective, marginally increasing in-channel capacity to approximately 8 cfs before flows go out of bank. While Scenario 9 (removal of vegetation choke points, some sediment removal) does significantly improve conveyance capacity over existing conditions (i.e. approximately 40 cfs in channel capacity), over bank flows are estimated to occur 33 percent more of the time (i.e. 4 % of total duration versus 3 %) relative to Scenario 8. Table 9 Percent of time flows are equaled or exceeded at each of the flow rate thresholds for flows passing through the project area (catchment MVL outlet at 148'" Avenue SE) based on HSPF simulation WY 1949 - WY2008. Flow Scenario Scenario Scenario Scenario (cfs) 1 7 8 9 6 24.04% 23.77% 23.41% 23.49% 10.4 13.77% 13.65% 13.44% 13.50% 28 6.03% 6.01% 5.99% 5.99% 40 4.01% 4.02% 4.04% 4.04% so 2.94% 2.96% 2.98% 2.98% 75 1.39% 1.42% 1.46% 1.45% 100 0.70% 0.74% 0.78% 0.77% 150 0.26% 0.26% 0.29% 0.28% 175 0.18% 0.18% 0.19% 0.19% 200 0.12% 0.12% 0.13% 0.12% 233 0.08% 0.08% 0.08% 0.08% 275 0.04% 0.04% 0.04% 0.04% 300 0.03% 0.03% 0.03% 0.03% King County 53 December 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 5.4 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Flow Scenario Scenario Scenario Scenario (cfs) 1 7 8 9 350 0.02% 0.02% 0.02% 0.02% 400 0.01% 0.00% 0.01% 0.01% IFHow Rates Competent to Pass Silts through the System Based on the estimated incipient motion for silts, shear stresses equal to or greater than 0.004 psf are capable to mobilize silty-fines assuming non-cohesive and median diameter size of0.000328 feet (0.10 mm). Using HEC-RAS computations of shear stress, it is assumed that shear stresses greater than or equal to 0.01 are capable to mobilize silts. Two flow rate profiles were evaluated for their competency: mean annual flow rates and 29 cfs. The goal was to obtain shear stresses above 0.0 I for the mean annual flow rate of 8.6 cfs throughout the project area. Results show that shear stresses do equal or exceed 0.0 I through the project area except for in the wetland downstream of 1481h Ave SE bridge (Table I 0). The threshold of 29 cfs is meant to represent that typically, there is at least one event of that magnitude each month between November and May-with a few exceptions during dry months. However, barely meeting the minimum target is not optimal given the possible inaccuracies in assuming non-cohesive silty fines. Fines with a diameter of I mm or greater require shear stresses above what the mean annual flow rate can produce. Moreover, during summer months when flows are their lowest, it would be expected that silts will settle on the channel bottom based on these results. This introduces another uncertainty about characterization of the fines when the next wet season starts. If vegetation has started to grow in the channel bottom, the root system will bind the soils together thus increasing the incipient motion threshold. Therefore, it is unclear what levels of flow rates are necessary to eradicate any new growths that may occur in the channel bottom during the summer. These results are also dependant on the relocation of where Long Marsh creek deposits gravels during storm events. This tributary has clearly been shown in the past to deposit enough gravels to effectively backwater May Creek upstream of its confluence. Additionally, shear stresses in May Creek are far below forces necessary to mobilize gravels that are being deposited by Long Marsh creek. King County 54 December 20 I 0 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Table IO HEC-RAS calculated shear stress in channel for Scenario 8, mean annual equals 8.6 cfs. Zero shear stresses are highlighted in tan color Station No. 4.9926 4.9882 4.9749 4.9687 4.9491 4.9372 4.9120 4.8874 4.8701 4.8680 4.8658 4.8613 4.8286 4.7885 4.7495 4.7207 4.7087 4.6403 4.6226 4.6177 4.6138 King County Mean Annual 0.01 0.02 0.1 0.53 0.04 0.03 0.01 0.01 29 cfs 0.03 0.07 0.25 0.26 0.09 0.08 0.05 0.06 0.29 0.32 Parcel#0223059005 footbridge 0.18 0.18 0.42 0.12 0.02 0.06 0.01 0.04 0.02 0.02 0.01 0.01 0.02 0.03 0.04 0.1 0.07 0.06 0.02 0.04 0.06 0.09 Station No. 4.6120 4.6112 4.6067 4.5754 4.5628 4.5516 4.5429 4.5323 4.5144 4.5076 4.5055 4.4974 4.4821 4.4814 4.4788 4.4729 4.4648 4.4613 Mean Annual 29 cfs McFarland footbridge 0.01 0.02 0.01 0.02 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.09 55 0.03 0.07 0.05 0.05 0.04 0.03 0.02 0.04 0.04 0.03 0.03 0.04 0.03 0.03 0.03 0.03 0.14 Station No. Mean Annual 29 cfs 4.4550 148th Ave SE Bridge 4.4512 0.01 4.4454 L __ ~ 4.4325 0.01 4.4265 0.01 4.4155 4.4116 0.01 0.01 --·-·--, 4.3947 o I 0.03 0.01 0.04 0.06 0.04 0.04 0.02 4.3876 I 0 0.01 I ______ _ I 4.3783 , 0 0 4.3713 ! 0 ,--~.~~ I I 4.36941 oj 4.3538 I 0 '-----· 4.3360 4.3234 4.3195 4.3108 4.2892 4.2861 4.2826 0.04 0.06 0.05 0.14 0.04 0.31 0.06 0.01 0.01 0.07 0.08 0.08 0.23 0.07 0.21 0.09 December 2010 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project 5.5 Durations of Flow Rates in the Ravine Using the results in the May Creek Phase II Sediment Transport Study, erosive flows in the ravine were observed to occur in the range of 73 to340 cfs, and a theoretical estimate of incipient motion approximate to 275 cfs. Refinements for the flow events used in that study, presented in this study, narrows the range of observed mobilization of sediment estimates for incipient motion to a range of75 to 275 cfs (rounding to the nearest 5 cfs). For this study, characterization of changes in erosion in the ravine are based on evaluating durations of flows above the defined incipient motion. As previously mentioned, an HSPF model was used to estimate continuous flows at one hour increments for a period of 60 years (from October l, 1948 through September 30, 2008) using scaled historical precipitation and evapotranspiration. This method enables a statistical characterization using observed historical climate data for May Creek in the valley and ravine that would not be available otherwise. Thus, any phases of dry years, wet years, and everything in between are contained in this analysis as opposed to any potential climate bias using local data of shorter time spans. Durations of flows evaluated in the range of75 cfs or greater for the ravine show that there are small increases that progressively get smaller the higher the flow rate. Comparing Scenario 1 to Scenario 8, these increases start with 0.07 percent increase at 75 cfs and become less than 0.0 l percent for flow rates at or above 275 cfs. As an example, there is 0.003 percent (i.e. 0.00003) increase in duration of flow rates between 300 and 350 cfs. Over 60 years of duration, that is equivalent to 15 hours increase or on average 15 minutes more per year (Table 11 ). This level of detail is beyond the accuracy of the calibrated model, but any biases in the models would be consistent such that relative comparisons between scenarios like this are valid. Table 11 Percent of time flows are equaled or exceeded at each of the flow rate thresholds for flows in the ravine (catchment CCP) based on HSPF simulation WY 1949 -WY 2008 (525,960 hours). Scenario Scenario Scenario Scenario Flow 1 7 8 9 6 43.26% 43.15% 42.97% 43.00% 10.4 25.06% 24.89% 24.63% 24.68% 28 8.84% 8.77% 8.66% 8.69% 40 6.10% 6.10% 6.06% 6.08% so 4.60% 4.61% 4.61% 4.61% 75 2.41% 2.44% 2.48% 2.48% 100 1.32% 1.36% 1.40% 1.39% 150 0.47% 0.50% 0.52% 0.52% 175 0.33% 0.34% 0.36% 0.35% 200 0.23% 0.24% 0.26% 0.25% King County 56 December 20 l 0 Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project Scenario Scenario Scenario Scenario Flow 1 7 8 9 233 0.1S% 0.15% 0.16% 0.16% 275 0.10% 0.10% 0.10% 0.10% 300 0.072% 0.074% 0.075% 0.075% 350 0.041% 0.041% 0.040% 0.040% 400 0.027% 0.029% 0.028% 0.028% Presented in all the scenarios except for Scenario 1 (existing conditions), the channel bottom profiles were based on survey elevations taken to the harden channel bottom and not on top of the soft sediment. This assumption is based on the fact that after the project when velocities are improved, existing silts will flush out of the system over some period of time. Although in-channel silt mobility analysis indicates improvements will restore competence to mobilize this material, there are in-channel features that will likely retard this process including re-vegetation by aquatic plants during summer base flow conditions, thus changing soil mobility characteristics and estimates of flushing for the next wet season. Lastly, the modeling verification is still in progress. Low flow conditions in the 10 to 20 cfs range should be validated to a reasonable accuracy, but given how well the model simulated for slightly larger flow rates (i.e.> 40 cfs), it's reasonable to assume that the model represents conditions at lower flows acknowledging that there will be numerous specific locations in channel geometry and vegetation blockages not included at every location. However, it is intended to include all major features. At present, the results of the modeling characterize out of bank flows in the 6 cfs range along with the durational analyses estimating that on average over time, pasture areas are flooded on average 3 months out of the year and likely longer. However given the preliminary hydraulic verification, existing channel capacity is uncertain at this time. King County 57 December 20 I 0 I I I I I I I D I I I I I I I I I I I I I I I I I I I I I Hydraulic and Hydrologic Analyses of the May Creek Channel Restoration Project 6c0c REFERENCES Bicknell, Brian, et al., July 2005. HSPF Version 12.2 User's Manual. Prepared for U.S. EPA- NERL. Prepared by Aqua Terra Consultants. GeoEngineers, 2008. May Creek Drainage and Restoration Plan, King County Washington. For King County Water and land Resources Division and Mid-Sound Fisheries Enhancement Group. Guo, Junke, 2002. "Hunter Rouse and Shields diagram." Advances in Hydraulics and Water Engineering, Proc. 13th JAHR-APO Congress, Vol. 2, 1096-1098. Helsel, D.R. and R. M. Hirsch, 2002. Statistical Methods in Water Resources Techniques of Water Resources Investigations, Book 4, chapter A3. U.S. Geological Survey. 522 pages. King County, 1995. May Creek Current and Future Conditions Report. Prepared by Foster Wheeler Environmental Corp. King County, 2002. May Creek Sediment Wedge Removal Project-HEC-RAS Model. Prepared by Entranco, Inc. King County, 2009. May Creek Sediment Transport Study. Prepared by Anchor QEA, LLC. Otak, 2006 USACE, March 2008. HEC-RAS, River Analysis System-Hydraulic Reference Manual (Version 4.0). U.S. lnteragency Advisory Committee on Water Data, 1982, Guidelines for determining flood flow frequency, Bulletin 17-B of the Hydrology Subcommittee: Reston, Virginia, U.S. Geological Survey, Office of Water Data Coordination, [183 p.]. [Available from National Technical Information Service, Springfield VA 22161 as report no. PB 86 157 278 or from FEMA on the World-Wide Web at (http://water.usgs.gov/osw/bulletin l 7b/bulletin 178.html). King County 58 December 20 JO