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HomeMy WebLinkAboutMiscCramer Northwest. Inc. o Surveyors o Planners o Engineers TECHNICAL INFORMATION REPORT OF SINGH PLAT 19029 120'" AVE SE RENTON, WA 98058 FOR BOB SINGH P.O. BOX 98412 DES MOINES, WA 98148 November 10, 2009 C.N.I. JOB NO. 2006-186 Prepared by Larry S. Krueger, P.E. 945 N. Central, Suite #104 Kent WA 98032 (253) 852-4880 Fax (253) 852-4955 www.cramemw.com E-mail: cni@cramemw.com . ~· TABLE OF CONTENTS I. PROJECT OVERVIEW II. CONDITIONS AND REQUIREMENTS SUll/illliARY Ill. OFFSITE ANALYSIS IV. FLOW CONTROL AND WATEIR QUALITY FACILITY ANALYSIS AND DESIGN V. CONVEYANCE SYSTEM ANAI-YSIS AND DESIGN VI. SPECIAL REPORTS AND STUDIES VII. OTHER PERMITS VIII. ESC ANALYSIS AND DESIGN I)(. BOND QUANTITIES, FACILlnr SUII/IIVlARIES AND DECLARATION OF COVENANT )(, OPERATIONS AND MAINTENANCE MANUAL APPENDl)(A APPENDI)( B APPENDl)(C OFFSITE ANALYSIS REPORT DETENTION AND WATER QUALITY CALCULATIONS POLLLUTION PREVENTION AND SPILL PLAN I. PROJECT OVERVIEW Existing Conditions: This project is located at 19029120th Ave SE in Renton, Washington. The property is approximately 2.14 acres. The property has an existing home, garage, and concrete pathways, all of which will be removed. The existing hol:lse has a few bushes nearby, along with lots of grass, extending to the east property line. West of the existing buildings there is virtually no vegetation due to recent clearing and grading activity. The existing site drainage mainly sheet flows from the north to the south. There are approximately 3 acres of upstream area that flow to the site. There is a half street (SE 191st Street) located along the southern portion of this project that was built as part of the Jesse Glen subdivision. Proposed Conditions: We are proposing that the property be divided into nine residential lots, along with a drainage and recreation tract. This project will finish the half street installed by the Jesse Glen subdivision to the south. All of the lots except Lot 9 will gain access from JUD Tracts connected to SE 191 st Street. Lot 9 will access SE 191 st directly. Runoff from the new homes will be din~cted to perforated stubouts prior to being conveyed to a conveyance system that directs the runoff to a combined detention/wet vault in the southeast cc,rner of the property. Driveway runoff will also be directed in a conveyance systom to the same vault. Once the runoff has been treated and detained, it will be conveyed to the existing drainage system along the west side of 1201h Ave SE. Upstream runoff will be collected near the northeast portion of the property and directed to the conveyance system of SE 191st Street completely bypassing our onsite drainage system. New catch basins and pipe extensions will be provided as part of the completion of SE 191 st Street. They will convey runoff to the SE 191st street drainage system and the pond of Jessie Glen to the south. II. CONDITIONS AND REQUIREMIENTS SUMMARY The core requirements of the King County Surface Water Design Manual (KCSWDM) for a Full Drainage Review Project have been or will be provided as follows: Core Requirement #1, Discharge at fthe Natural Location: The site's drainage pattern cum:lntly tends to sheet flow from the north to the south and once it reaches SE 191 st Street ultimately flows east to the road drainage system in 120th A.ve SE. All new onsite impervious surface runoff will be routed to a conveyance system and conveyed to a combined detention/wet vault. It will then be conveyed to the existing drainage system along the west side of t201h Ave SE. Core Requirement #2, Offsite Analynis: An offsite analysis is provided in Appendix A. Core Requirement #3, Flow Control: Detention calculations are provided in Appendix B. Core Requirement #4, Conveyance System: A conveyance system has been designed to direct onsite runoff to the new combined detention/wet vault. The system consists of catch basins and pipes. It is located on the north side of the site's frontage improvements. There are also new catch basins and pipe extensions proposed to collect the road drainage of SE 191 61 Street. The runoff is conveyed to the existing drainage system for thei subdivision located south of SE 191 st Street and flows into their detention pond. Conveyance system calculations will be provided at a later date if required. Core Requirement #5, Erosion and Sediment Control: An erosion and sediment control plan has been designed. Some of the ESC measures to be provided are a stabilized construction entrance, silt fence, inlet protection and seecling. Core Requirement #6, Maintenance and Operations: A maintenance and operations manual will be provided at a later date if required. Core Requirement #7, Financial Guarantees and Liability: The owner will provide this information prior to permit issuance. Core Requirement #8, Water Quality: Water quality calculations are provided in Appendix B. Ill. OFFSITE ANALYSIS A Level 1 Offsite Drainage Analysis is provided in Appendix A IV. FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN Flow control and water quality calculations are provided in Appendix B. V. CONVEYANCE SYSTEM ANALYSIS AND DESIGN The conveyance system will consist of catch basins and pipes. Calculations will be provided at a later date if required. VI. SPECIAL REPORTS AND STUDIES No special reports or studies are knov,n to exist for this project. VII. OTHER PERMITS No other permits are known to be reqi:1ired at this time. VIII. CSWPPP ANALYSIS AND DESIGN An Erosion and Sediment Control Plan has been designed and is included as part of the engineering plans. Some of the ESC measures to be provided are a stabilized construction entrance, silt fe,nce, inlet protection, clearing limits and seeding. ESC BMP's are addressed in detail in the Stormwater Pollution Prevention and Spill Plan that is provided in Appendix C. IX. BOND QUANTITIES, FACILITif SUMMARIES AND DECLARATION OF COVENANT This information will be provided at a later date. X. OPERATIONS AND MAINTENANCE MANUAL A maintenance and operations manual will be provided at a later date if required. APPENDIX A OFFSITE ANA.L YSIS REPORT Cramer Northwest. Inc. o Surveyors oPlanners oEngin,eers LEVEL 1 DRAINAGE ANALYSIS OF BOB SINGH PLAT 19029 120tR AVE SE RENTON, WA 98058 FOR BOB SINGH P.O. BOX 98412 DES MOINES, WA 98148 JULY 5, 2007 C.N.I. JOB NO. 2006-186 Prepared by Paul J Nitardy, P.E. 945 N. Central, Suite #104 Kent WA 98032 (253) 852-4880 Fax (253) 852-4955 www.cramermv.com E-mail: cni@cramemw.com I. TASK1 II. TASK 2 Ill. TASK 3 IV. TASK 4 V. TASK 5 APPENDIX TABLE OF CONTENTS STUDY AREA DEF'INITION AND MAPS RESOURCE REVIE:W FIELD INSPECTIOIN DRAINAGE SYSTE:M DESCRIPTION AND PROBLEM DESCRIPTIONS MITIGATION OF EICISTING OR POTENTIAL PROBLEMS THRESHOLD ASSIESSMENT AND PRELIMINARY CALCULATIONS TASK1 STUDY AREA DEFINITION AND MAPS TASK 1 STUDY AREA DEFINITION This project is located at 19029 1201 h Ave SE in Renton, Washington. The property is approximately 2.14 acres. VVe are proposing that the property be divided into nine residential lots, along with a drainage and recreation tract. Some of the lots will gain access directly from the new road to the south of the property, (Road A). The rest of the lots will gain access from JUD Tracts connected to Road A. The property has an existing home, garage, and concrete pathways, all of which will be removed. The existing house has a few bushes nearby, along with lots of grass, extending to the east property line. West of the existing buildings there is virtually no vegetation due to recent clearing and grading activity. The existing site drainage mainly sheet flows from the north to the south. There are approximately 3 acres of upstream area that flow to the site. We will plan to allow this flow to bypass our site by providing a separate system for conveyance. MAPS A vicinity map, sensitive areas map, aerial/topo map, and offsite drainage map can be found in the proceeding pages. ..0. "6"' .L V.L 1 (@)) King County vi " ~ SE 179TM Pi. SE 179Til ST §. .. § ~ SflaJT"ttST ~ ~ ,, SE UUSTST Iii I S!:1~0ST ~ SE 183ROPl § :Jj• '" ,. " :c. ij· ' ' !JI sf '< ,- ii " ., •. \ + ~·,~Dc.1 ~ liJ ~ It z _, ~ { "'-~ -... \ Sc;. 184Ttt Pl ' vi SE 1Mrtt ST ~ S£1Mnlt.N i t# 4! " !:: Si:.,5&,;t'IPI. -· _, \. . Pan!'het· Lake \ . l,, \ \ ' SINGH • VICINITY MAP SE. 198Ttl ST !E 196TH ST 0 SE 1915TH Cl SE 199TffCT .SE~ST 0 SE 1il1ST ST : \ I I /'~ ! q, ,I l. \ 1522!1 -,.....:: \ \..., he information included on this map has been compiled by King County staff from a variety of sources and Is subject to change without notice. King County 'makes no representations or warranties, express or implied, as to accuracy. completeness, tlmellness. or rights to the use of such information. King. County lshall not be liable for any general, special, indirect, incidental, or consequential damages including, but riot limited to, lost revenues or lost profits resulting from he use or misuse of the information contained on this map. Any sale of this map or infonnatJon on this map is prohibited except by wr1tten permission of King lcounty. · hate: 3-5-2007 Source: Kin ... Countu IMAP -Kina Countv Parks lhttn://www.metrokc.cov/GIS/iMAP\ http://www5.metrokc.gov/servlet/com.esri.esrimap.Esrimap?ServiceName=overview&ClientVersion=4.0 ... 3/5/2007 Map uutput Page I of I @ King County S£' 1.!19TH ST ' SE 100T~I ~"4;, SE HUST CT li! "' ~ < m ~ ;; .: + § e'!I Seleclt>d Par,::.els -I Counl)" Boundary ·-x ~.t.>unlain Peaks. CAO Shoreline Conditr.Jn Hi-Jhways ,/4/ ln?.Hpordled Area Street!> -'i " SINGH -SENSITIVE AREAS SEtMhtST r 0 Legend Parcels SAO Stream ~ C1a;.~ 1 C'.$,!-2:>c--e-n.:i /V C·=2.S.,rncnd // C:.:is.'ll-) l.J:c.r-z.::~<d D Lakes and Large Riven;. /., .• / Streams ~ Floodway D 100 Year FkJodplain Im SAO Welland ~ SAO Landslide ~ SAO Seismi; SAO Ef"Jsion e information included on this map has been compiled by King County staff from a variety of sources and is subject to change without notice. King County akes no representations or warranties. express or implled, as to accuracy, completeness, timeliness, or rights to the use of such information. King County hall not be liable for any general, special, indirect, incidental, or consequential damages including, but not limited to, lost revenues or lost profits resulting from he use or misuse of the information contained on this map. Any sale of this map or information on this map is prohibited except by written permission of King ounty. ate: 3-5-2007 Source: Kin Coun IMAP -Sensitive Areas h :/lwww.metrokc. ov/GIS/IMAP http://www5.metrokc.gov/servlet/com.esri.esrimap.Esrimap?ServiceName=overview&ClientVersion=4.0 ... 3/5/2007 Map Output Page I ot I @ King County e information included on this map has been compiled by King County staff from a variety of sources and is subject to change without notice. King County kes no representations or warranties, express or Implied, as to accuracy, completeness, timeliness, or rtghts to the use of such infonnation. King County hall not be liable for any general, special, indirect, Incidental, or consequential damages including, but not limited to, lost revenues or lost profits resulting from e use or misuse of the lnfonnation contained on this map. Any sale of this map or information on this map is prohibited except by written pennission of King unty. ate: 3-5-2007 Source: Ki iMAP -Sensitive Areas htt :ttwww.metrokc. ov/GIS/iMAP http://www5.metrokc.gov/servlet/com.esri.esrimap.Esrimap?ServiceName=overview&ClientVersion=4.0 ... 3/5/2007 1VH1_1-' VUl!JUl J. <4!:,"-' t Vt ! @) King County he information Included on this map has been compiled by King County staff from a variety of sources and is subject to change wllhout notice. King County akes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such Information. King County hall not be liable for any general, special, indirect, incidental, or consequential damages including, but not limited to, lost revenues or lost profits resulting from he use or misuse of the lnfonnation contained on this map. Any sale of this map or Information on this map is prohibited except by written permission of King ounty. ate: 3-5-2007 http://wwwS.metrokc.gov/servlet/com.esri.esrimap.Esrimap?ServiceName=overview&ClientVersion=4.0... 3/5/2007 .. .. , .~. oc ······w .· ~ rr=•. . It) . -- I I cf__ [ -@a=- c.o TASK 2 RESOURCE REVIEW ,, TASK 2 RESOURCE REVIEW Adopted Basin Plans and Finalized Drainage Studies: The property is located in the Soos Creek Basin Plan. Basin Reconnaissance Summary Repc>rts: No known reports are known to exist. Critical Drainage Area II/laps: The site is not known to be located in any critical drainage areas. (FEll/lA) II/laps: The site is located outside the 100 year flood plain. Other Offsite Analysis Reports: ESM Consulting Engineers, L.L.C. has produced a TIR for a development named Jessie Glen, part of which occupies the property directly south of our site. One King County related permit number for this project is L05SR054. Sensitive Areas Folio: There are no sensitive areas located on this site. DNR Drainage Problems II/laps: Not applicable. Road Drainage Problems: Not applicable. King County Soils Survey: Soils on this site consist of Alderwood gravelly sandy loam, 0 to 6 percent slope (AgB). Wetlands Inventory II/laps: There are no wetlands located on or near the site. 11/ligrating River Studies: Not applicable. Drainage Complaints: Several reports are included in this level 1, but none of them are believed to be currently applicable. l!NlFH!.TRATION TEST & OBSERVATIONS Date: January 25, 2007 Site address: 19029 120th Ave. SE. Renton, WA 9805S Job No. 2006-186 SQILLQGS; A$ requeatc:d, soil log holes were dug at the above referenced parcel of land. The test holes have been flagged and numbered for future inspections. CAUTION: IT IS THE RESPONSm!LITY OF THE PROPERTY OW!,.1ER. TO COVER THE TEST HOLES TO PREVENT INJURY TO PEOPLE OR A,\llMALS. Soil logs-#1: o -12" disturbed/ fill 11oil, 12·· -23" brown sandy loam, water@ 17''. #2: O standing water. WATER DROP TEST; #3: O -24" brown sandy l,)am, water@ 17". #4: 0 -32" brown sandy l•l.am. water @ 31". #5: 0-28" brown sandy l,lam, water@ 27'' #6: O -25" brown sandy k>am, @ 25" gray sandy loam water@ 25" Soil log # l : No water drop test due to only 5n of soil. Soil log # 2 : No water drop test due to standinl! water. Soil log # 3 : No drop. Soil log# 4 : 6.0" -21.0" @ 2.0 MP!. Soil log# 5 : 7.0" -19.5"@ 2.4 MPI. Soil log# 6 : 6.0" -14.5" @ 3.5 MPI. OBSERVATIONS; Standing waw was obscived in the area indicated on the attached site map. No other ingnlficant storm wa1er is!IICS observed en this me or surrounding properties. ~~ Burton N. Staton r , ·.J ----::,~:;;-: ... ;:-:-·--::~.·-;.:,-··· ------. "':';" --~-·-..... o '1. ct• N ~'·- -----~---·-----':l'W i/\V HJ.0?:L <D , ... • " ,. ~ rt<. ~ <!~ -""l'i: . .. ~1' .,,., ! .,l;i .. • .. ~ • 7'. 2 ~ ~ ~ l~ ~ ~ ~ ~ -H ,, • ~~e 5 ~ "I ~1 = ~~ " .. 'Ji 5! ::: -~ \)) ~ V> ~ ~ -2.. -( 1.'l"'~,l,,£1)VI /.,V)!ll K.iqg County Water and Land Resourcet; (WLR) Division 201 S Jackson St, Suite 600 Seattle, WA 98104-3855 FAX Date: _J.'-.J. C-L...L.1-'"--=='--- Number·of pages including cover sheet: j' ' ·.;, ,•-· ".;; ·.,-<. From; Cindv Torkelson WLR Stormwater Services Section Phone: 206-296-1900 Fa.,: Number: 206-296-0192 IMPORTANT LEVEL I ANALYSIS SOTE: We do not send copies of certain complaint types that are not relevant such. as BCW, FI, FIR, FIH and WQA, and we do not send CL and LS types. See key below. Type SI, S2 and S3 V\,ill not be faxed due to size constraints. The fol10V1fog is a list of complaint types receiv(:d by the Water and Land Resources Storrnwater Services Section. Complaint numbers beginning prior to 1990-XXXX have be3n archived and are no longer in our possession. They can still be retrieved, if necessilr)', but will take additional time and may not be beneficial to your research due to their ag~. development which has occuned, etc. If you sxe interested in reviewing the actual complaints, th,:y c211 be pulled (time pennitting) for your re,~ew. Copies can be obtained for $ . l 5 per page, and $.2.00 per page· for plans. Km. Jnc ftf tnvesflgrrtion ' C Action. R.t.quelL BCW Busln.,,• (\)1 Cic,m Wa:« CCF R<,ponso to IDquuy •cL amm EH Bnfor,;c01c;:n1 on Hold ER Enforccmc;:m Rnlew Pcc.FCR,FC.S Fooility Complaitl!I Fl SWM Fet :nqulry PO:.. S\\r'!\l Fee Review FIH SWM Foe on Hold •L,5 L11wsoit RR Fil.Cillty &i,inowing f/..e'V'iew ~'DA Ne\g.,borbood Drllina~I An~t= WQC W ... r Quality CO?l11)1Wlt WQE Wo'.orQuality Enforetmettt WQR Water Quality Engineering Rovl'1'/ WQA W-Quality Auuit WQO WIiler Qu,llity-Ott!cr 3 ! .S2$N3 Engir.eerhtJ Studie4 Tzya of Problem DCA DDM DES DLE DTA llsQ MMA MMF MMG MMM ~! MNW S\VF WQB · WQD,·, WQI !\EM Gl\T NWD Doveloprn~nt/Comcn1c1ior. Drainage· Misctlla.ic0us Drnlnagr;-Etlsion/Sedlm~mat!c11 Dni11ap-Wddid~Sartb. Mcva:ntt11 Dreincge Technk31 A5Si.r.:~ce Dmlnage.,., Otn~al lng,.1iry Mlllnter1ance -A.mbet!cs Maiotwi.ance • Pl"oding: Mainttnam:i: • Ot:nt:!31 Malntmmict -Mow:ng Moin~n,noc:-Needs Mafatcnwe Mllintcntmce,.Noxi\'a., Weeds SWM: F~ Questiow; Wmer Qualfly-am: Man"e.rocnt Practi~~ WfJ!J:Jt Quality-Dumpin,g W;1.1m Qu.Mtr-Ilifolt Ccn:i.o~'tlo.n. SWM .F'e,e -R.emcwl'Clnent S\l'M fe<-Orelll SWM fce,,,Now Di.scCJunt J?, '/, ! ], LIJJ I L, U:JriV 11 ·.,, .1 •,, J I !ting County Water amt Lmul llasources llllfisiuo -llrai118118 Serviill89 &81l111151 Complaint SBBl'cll Pri•ted: 01/19rl0077:26:<16 AM ~ TJPll Typa Ill Pl'8lr.l Allfi'088 DI Pl'lll!IDDI · lmJl!nts Tbrllil P&!IB l'lllnlll8r C8l!3 1975-0076 C FLOG RD WY/FLD'0/112TH AVE SE/SE 186TH ST 680E2 1977.0003 C ORNG 12207 SE 192NDST @ GOLDEN HILLS 686F3 197i.0072 C FLOG 12202 SE 192ND ST 686F2 1978-0028 C DRNG 20205 106THAVESE 666E:l 1978.0080 C PONDING 19246 121ST PL Sic EAST OF BENSON HWY 6a6F2 1978--0061 C DRNG 19246 121STPL SE 686F2 1 W71Hl047 C 11403 SE204TH ST SOIL BULLDOZED/P/,NTHER LK AREA eaae2 1961-0081 C DRNG 1S917 122NDPL SE BLOCKED/EAST HILL AREA 686FJ 1981-0215 C DRNG 19918 122NDPL SE C/B CAVING IN 686F3 1962.0539 C FLOG 126CC SE 192NDST EAST KENT AREA 6B6F2 1983-0194 C DRNG 1061H AVE SE 6666:3 1883-0199 C 10860 SE 196TH FILLING & GRADING e88E3 1983-0424 X DRNG 12ij2B SI: 202NO PL SYSTEM MAINTENANCE 666F3 1984-00ilS C FLOG 20204 106THAVE Si: 686E3 11iS4-0313 R FLOG 13250 SE 192NO ST TO ROADS DrJ.4 686F2 1$84-0314 C FLOG 13250 SE192ND ST SE 192ND ST/134TH AVE SE 6S6F2 1964-0324 C DRNG SE 204TH ST/124TH AVE 6S6F.: 1986-0702 C DRNG 1Z!40 SE 200TH ST MAINTENANCE OF LOT 58SF3 1988-1166 C FLOG 11202 SE 186TH ST S,ORM OVERFLOW 686E2 1926-1185 C FLOG 11202 SE 186TH ST SEE: 86-1168 BRYANT, SILL 686E2 19&1-1190 C FLOG 11001 SE 186TH ST BASEMENT GEinNG WATER 6861:2 1987-0246 C FLOG 202J6 127TH ;>L SE WATER FROM NEIGHBORS 87--0918 68SF3 1987-0334 C DRNG 11202 SE 186TH ST CULVERTS BLOCK!oD 86°1166, 1185 6881"2 1987-0471 C FLOG 11202 SE 186TH ST SPRING GLC:N ee-115(), 1185 686E2 19S7-0S4S C, DRN13 18627 109TH AVE SE INADEQL:ATE SYSTC:M 68SE~ 1987-0875 C DITCH 19407 124TH AVE se DRAINAGE: CITCH ON PROl'E:R'iY 58~F3 1987-1049 C ro RD COORD v4/27/e7. 685F2 1988-0238 C FLOG 18431 120TH AVE SE NEW DRIVEWAY WILL n·. FLOOD 586F2 1988-0238 ER PIPE 18431 120THAVE SE NEED EXTENS:ON OF 42" CUI.VERT 6B6F2 1SSS.u551 C DRNG 20002 124TH AVE SE FILL IN WETLANDS 5B6F~ 1989-0003 C DRNG 18612 120TH AVE SE INCREASED RUNOFFICHANNeL 5B6F'2 1989-0019 C DRNG 19400 124TH AVE SE DITCH MAINTENANCE S85F3 1989.0192 C DRNG 18612 120THAVE SE X PIPE.NOT WORKING 686F2 1989--0410 C ORNG 12'213 SE 199TH ST PONDING IN DRAINAGE :ASEMENT 685F3 1989-0660 C DRNG 16631 111TH F'L SE SIN ORNG AND DAMAGE 686E2 1889-0700 X ORNG 18631 111TH PL SE WATER ON SIDEWALKIS9-0650 FRITON 6S6E2 1990-0076 C DRNG 11254 se 186TH ST PLUOOED CULVERT/SlORM 686:=2 ~!II~ W ~LKU :'W, ) <· i COIIIIIIBlnt Tyt111 TV~ of Pl'ablam AdYOIS or PrOblam conunmta TbrosP8Ua bar Cm!9 199()..0141 C FLOG 18400 112TH AVE SE PONO OVERFLOW/90.0149,235,372/STOR 68SE2 199C-014Q C FLOG 112C2 SE 186TH ST RID POND OVERFLOW,1<08ERTI STORM E 686E2 199C-0231 C DRNG 18426 112TH /\VE SE RID POND OVERFLOW/STORM 90-274,37 58BE2 1920-3235 C FLOG 11202 SE 186TH ST WATER IN BASEMENTISTORM/90-141,149, S88E2 1G9C-0274 C FLOG 11022 3E 184TH PL RID ?ONO FLOODEDISTCRM 686E2 1eso.0342 C FLOG 11202 SE 186TH ST RIO POND/ROBERTI STORM EVENT SB~l:2 1990-0372 X DRNG 11202 SE 186TH ST RIO PONDS OVERFLC-W919Q.141,149,235,2 689E2 1990-0664 Ell MANHOLE 12400 SE 201ST PL FALURE·LINDA CREST PLAT DIV 1 & 2 686F3 1990-0709 CL FLOG 18604 112TH AVE SE CL#12959 SEE CLti1322~ DUE DEC~MBE 6BBE2 1990-0884 C DRNG 18427 112THAVE SE RID POND DRAIN.'IG8STORM 585E2 1S6C-10o1 CL FL.OG 11202 SE 1am; ST . CL.#13224 SEE CL#12&59 GARAGE FLOO 696E2 1SS0-106i C DRNG 12025 se 1SllTI-1 ST SPRING HILL ONE/DITCH NOT DRAINING 686F3 1990-1186 CL FLOG 11044 SE 186TH ST MEMOIRUDDELLS STU'.lY T•:l PA 636E2 1911C-1212 C DITCH 11044 SE 186TH ST RO/SIDE DITCH-FILL/90-1186 686E2 1990-1212 E FILL/DIT 11044 SE 186TH ST WILL START WORK 09120 CHK ON 09/30/93 5B6E2 199Q.1212 ER FILUDIT 11044 SE 186TH ST RUDELLS STUDY 686E2 19~0-1226 C ORNG 18615 107TH AVE SE FLOODED BASeMENTIBACi ROADWAY 68~E2 1990-1445 C DRNG 18427 112TH AVE se Rltl POND OVe:RFL.OWING TO STUDY/91-1 $o6E2 1990-1$30 SR FL.OG 18427 112TH AV5 SE STORM EVENT 688E2 1990,1531 SR FLOG 18427 112THAV5 SE STORM EVENT NOT NDAF 6651:2 1991.0150 C ORNG 11l824 112THAVE SE 086E2 1961-01SO SR DRNG 18624 112THAVE SE NOTNDAP 686E2 1961-0196 C FLOG 18425 112TH AVE SE 685E2 1991-0196 SR FLOG 1842! 112TH AVE SE NOTNDAP 686E2 1991-0253 C DRNG 11264 SE 166TH ST 686E2 1991-0299 C FL.DO 19835 121ST AVE SE OVERFLOW OFF l"IPES 6B6F3 1991-0299 SR FLOG 19835 121ST AVE. SE REFER TO BALC 6a6F3 1991-0338 C F'LOG 11214 se 195TH ST LEVEL OF PANTHER LAKE/STORM EVENT 686E3 1991.0338 SR FLOG 11214 ss 1911TH ST STORM EVENT NOT NDAP 686E3 1991-0426 C FLOG, 12100 SE 137TH ST WASHOUT OF ROAD/DEVELOPEMENT 686F3 1991-<>438 S1 SPK TO FINISH S'. 3/4-S2 TO '92 CON 886E2 1001-0667 CL DRNG 18427 112THAVE SE SEE 91-0438 Sci: RUDOELLS B86E2 19.q1-0837 C OAMAOECB 19001 11eTHAVE SE C/8 BELOW GRl'DE 686E2 1991-1005 C DRAINAGE 12213 SE 19ijTH ST PONDING IN YARD/FENCING 6S6F3 1991-1096 C FLOG 11200 s.: 168TH ST RUDDE:LL PONO OVERFL.OW 636E2 1991-1120 LS FLOODING 193DO 10BTHAVE SE 688(:3 1001-1132 C DRAINAGE 19006 116TH AVE SE INFOTOPM&O 686E2 1991-1149 X FLDGRIC 11200 SE 184TH ST CCF# SWM-1031 RJO PONO CAPJCITY 686E2 1991-1160 C DRAINAGE 11007 SE 196Trl ST INFO TO BALCI DIU./PARKINO LOT EXPANS 686E3 1994-0038 C PONOING 11430 SE 192ND ST FOSS GRAOiNG/FILUNG VIOLATION 686E2 ·.'/'\~, I), li)l'I £.'JillT I\ J 1\V VV, ii I.. I',';/ '._,, _, V .J ' ~t lyp lype llf Pl'Obl6m A'1!fo88 Of Prlllllem Cllmmllllfs Jlll'UB l'llllll 1£:i11BI' r.a1111 1gs4-04ga C DrTCH 19701 121ST AVE SE GRAVEL DUMPED IN ROADSIDE DITCH 686E3 1996-0226 WQC MUD FLOW SE 196TH & 118TH}. SE RFDDES GRADING 686E3 1895-0594 C DITCH 19803 121STAVE SE REQUEST TO ENCLOSE R/S DITCH 586E3 1B95-0974 C FLOODING 19701 121STAVE Se APPARENT oasTRUCTION IN R/S DITCH 6S5E3 3 1995-1087 C RUNOFF 19831 121STAVE SE EROSION FROM Nl:W SCHOOL CONST 6851:3 " 1998-0243 C DRNG 1sea1 121STAVE:: SE DOWNSTREAM IMF'ACT SCHOOL DEVELO 6961:3 " 1996-0245 C RUNOFF 19526 122ND PL SPRING HILL EU:MENTARY INFO RDS DIT "< I-SE 686F3 "' ....., ,I;: 1996-0788 C FLOG 12'232 SE 200TH ST FLOODING DUE TO STORM ANO SUBSTN 896F3 :::,... ~ 1996-0788 NOA FI.OG 12232 SE 200TH ST FLOODING oue TO STORM AND SUBSTN 696F3 .. /.U :x 1996-0788 R Fl.De;, 12232 SE 200TH ST FLOODING DUE TO STORM ANO SUBSTN 68~F3 ~ " • 1006--0805 C DRNG 19400 120THAVE SE DRAJNGE FLOW QUESTION DEVELOP INF 685E2 "' ...J "" 1096-1233 C FLOG 19910 11BTH AVE SE GROUNDWATER IMPACT TO PVT PROP 685E3 /-.. 1-. 1996-1550 C DRNG 19121 124TH AVE SE PLUGGED ON/ CUL.VERT IMPACT TO PVT 6SSF2 !.!, " "' ~ 1a96-1564 C DRNG 18908 113T1-i WAY SE PRIVATE PROPERTY l~PACT TO PVT ORN 5aSE2 , 1996-1613 C FLOG 19910 118THAVE SE ROOF ORNS PLUGGED PVT PROB 686E3 ~ • • 181l6-1636 C ORNG 20024 124TH AVE SE ROAD iMPROVfMENT PROJECT IMPACT C 686F3 1996-1906 E RA:l POND 12813 Se 232ND PL FENCE ENCROACHMENP INTO TRACT 686F3 1997-1123 C GRADING 18908 113THWAY SE PVT PROP IMPACT NO DRNG NSTA'..LED 686"2 19!17-1123 R GRACING 18908 113THWAY SE PVT PROP "'1PACT NO DRNG INSTAl..i.ED 686E2 {"""" C DRAINAGe 19113 121ST PL SE INSTALLATION OF DRNG !N R/W OLD/OFF sse;,2 1997-1179 NDA DRAINAGE 19113 121ST PL SE INSTALLATION OF DRNG :N R/W OLD/OFF eaeF2 1997-1179 R DRAINAGE 19113 121ST PL SE INSTALLATION OF DRNG :N R/W OLD/OFF eaeF2 1997-1301 C DRAINAGE 19125 121ST PL SE SUBSTANDARD INSTL OF DRNG SYS PVT 686F2 1997-1505 C TREES 12232 SE 200TH ST DANGEROUS TREES ON COUNTY PRC,P 686F3 1997-1550 C FLOODING 18631 121STAVE SE PVT PROP IMPACTS UPBASIN DEVELOPM 686E3 1997-1550 R FLOOOINIJ 19!i31 121STAVE SE PVT PROP IMPACTS UPBASIN OeVE:LOPM 686E3 1997-15SO $1 FLOODING 19631 121ST AVE SE PVT PROP IMPACTS UP8AS1N DEVELOPM 686E3 1997-1572 C TREE 12232 se 200TH ST REMOVAL OF WINDFALLS REQUIRED 686F3 1998..0019 C ORA:NAGE 19016 111!TH AVE SE NEW GRAVEL RD POSSIBLE ?VT PROP IM 6861:2 1ij8S-OOS8 C DRAINAGE 10620 116TH A\IE SE SFR CONST IMPACTl:\iG ADJACENT F'ROP 686E2 1999-0108 woe OILSPU. Se 199ST/124AVE SE SPILL. OF POLLUTANTS ALONG RD R/W eaeF3 1998-0361 C DRAINAGE 12463 SI: 196TH PL. INFO REQURST '<E WET:..ANO/OPEN SPAC 888F3 -4190a-092e C DRAINAGE 1il133 121STPL SE APPARENT OBSTRUCTION IN ROAD DRNG 68eF2 _ _, _______ -.. --·- 1999-0306 c; DRAINAGE 11618 SE 188THST ADJACENT F'ROP PAVED 2500 SQ FT 686E2 1999-0SOJ C FENCE 12466 SE 198TH PL REQUEST FOR FENCE BOLLARDS AT ACC 666F3 2000-0398 C ODM 12825 SE 192ND ST REQUEST TO DIVERT FLOW DISCHARGIN 686F2 -r 2000-0572 C DOM ACROS 19029120TH AVE SE (APPARENT FIU.ING OF ROADSIDEDITCH., B86E2 -?2000.osn R DOM ACROS 19028 120TH AVE SE \ APPARENT FILLJNC CF ROADSIDE DITCH. ) 686E2 ·se ___... 2000-0713 C DOM 1:2232 SE 200TH ST r INCREASE FLOW'NS IMPACTING DR"-INA 686F3 2.000,-0713 NDA-DOM 12232 SE 200TH ST \ INCREASE FLOWS .IMPACTING DRAIN/I.GE 686F3 \_ µ~r / nf,fl.T/1,Ali f 4 THI{ if. Ef,tfT Page! or• COlllPlllilll lldmliur 2000-0713 R DOM 2001-<11 S1 C DOM 2001-0360 FCC MMG 2C01.0360 t.lDA-MMG 2001-0360 R MMG 2001-0416 WQC WQB 2001-0455 WQC WQEl 2001-04ss waR was 2002-0403 C MMA 2002.0553 C OTA 2002-0S60 FCR MIIIW 2003-0230 C DCA 2003-0230 R DCA 2C03-0545 WQR WQB 2003-0762 WQA WQAi 2003.084 7 C DOM 2002-0847 NOA-DOM 2003-0847 R DOM 2002-0909 WQC WQDR ~004--0337 SUP REC 2004-0337 SUPF R!=C 2004-0368 FCS MNM 2004-0453 wac waoR 20:)4-0536 FCR MNM 2004-0952 C OTA 2005-0107 C RFN 2005-0107 NOA-RFN 2005--0107 R RFN 2006-0180 C RFN 200Li-02.44 C DOM 2005-031!! C OTA 2005-0428 c RFN 200$-04<\ll WOA WQAI :l:006-0452 WQA WQAI 2005--0682 FCR MNM 200&0012 C 2006-0299 C 2006-0450 C RFN RFN OTA !\!1\1.i \,'J. l;L~V .Alldran or PPOblOlll 12232 SE 200TH 12026 12025 12025 12232 12313 12313 1Z135 19013 1,~eo 1145S 11455 18801 194JJ 19230 19230 192JO 1aeo1 12462 12462 12232 12212 19406 12701 19701 19701 19701 19421 18617 1250::l 19128 12800 19406 1ij133 19625 1SS21 16621 116TH AVE SE 8 SE 196 SE. 196TH ST SE 196TH ST SE 196TH ST SE 200TH ST SE 198TH S1 SE 198TH ST SE 199TH ST 114THCTSE. 117TH PLSE SE 191HH ST SE 196Tl, ST 126TH PLSE VASHON HWY SW 116TH AVE: SE 118THAVE SE 11b"TH AVE SE 126TH PL SE SE 198TH PL SE 198TH PL SE 200TH ST SE 199TH ST 116THAVESE sE 131sT PL 121ST AVE 121ST AVE 121ST AVE 116THAVE 126TH "L $E 188TH "I. 11STHWY SE 192ND ST 120TI-I AVE 113TH WY 116THAVE 116THAVE 116TH AVE 11·.,, .;!.•.1, ST !NCREASE FLOWS IM,0 ACTING DRAINAGE 686"3 GROUNDWATFR DISCHARGE OV=:R SIDE 686E3 OFFSITE FLOW ONTO PRIVATE F'ROPERT 6/lSE'.\ OFFSITE F'LOW ONTO PRIVATE PROPERT eeees OFl"SITE FLOW ONTO PRIVATE PROPERT 68eE3 CONCERN Of' SOA:> SUDS BEING DISCHA 66€FS APPARENT LACK OF POLLUTANT CONTR 686F:? APPARENT LACK OF POLLUTANT COMTR 686F3 REQUEST TO REMOVE TRl:ES ON COUNT o86F3 COI\CERN REGARDING POSSIBLE SLOUG 686E2 REQUEST TO REMOVE TANSY RAGWOR1 6B6E3 APP:.RENT DIRT BERM CONSTRUCTiON. 686E3 APPARENT DIRT BERM CONSTRUCTION. 6&6E1 PROBLEM CORRe:creo RP MOVED 68eF2 BMPS are ALL IN PLACE S86F2 APPARENT OBSTRUCTION OF OFFS/TE C 68BE2 APPARENT OBSTRUCTION OF OFFS/TE C 68Se2 APPARENT OBSTRUCTION OF OFFSITE C 8851:2 AUTO FLUID RE81DUE ON STREET AS AR (l86F2 PARKS f1EQUEs·r TO INSTALL TRAIL AND 566F3 PARKS REQUEST TO INSTALL TRAIL ANO 686~3 S8SF3 Possible WQ problam o' gasoline In otormsyr. 68aF3 Bioswa!e fil'ed In? ln.,esligatian shows oo bios 8BSE3 R•!iirral m,,r, KC Roads. Flooding of boekyard 68SF'2 SE ConO@m about impact from n•W dovelopm,nt 68SE3 SE Concern about impact from now d8""1opmonl 686!:3 SE Concern about lmpacl from new devt1lopment. , ,asES SE New ditch caicslng flooding 1, eroe. l"v,,>tigatio 6BBE'3 SE Wel. ba:~Kyard ca:.;sed hy broken storm line1 in 69.t.iF2 Backup ii KC Rd oonveyanoo sy,;tom. lnvostg eae;:2 SE Wdr.er f,ows aoroee sidewalk from wanu m~lii!r. IS80E2 BMPS IMPI.EMl:NT'ED AS PART OF KENT S aaoF2 SE 6MPS IMPLEMENTED AS PART OF SITE VI 58~i:S SE Roforral /rorn KC Hea~. R~ in 091898. Inv f 68~:'2 SE Water :n bason-.,,t. rnv did not nnd an)' '<C ,to ~8653 SE Broken dra:nage pioa@ Benson 11111 Elem Sch 686C:2 SE School eonst causing water saapage into yard. eseEZ JJJJ -1177 IJ)l -13~1 I 9J g -OJ;.J f o it,v\/1 f: fl)-(,:' ·) F• [ [O"J!~, f/l'Sff I f• ll" V /,'/h /f'Q'i> ! 1Hr1JJ1t r1try r 11lr. JV;,' ._iJl/lU~r f~•IILEIIJ F-aga 4 of 4 King County Water and Land Resource~ (WLR) Division 201 S Jackson St, Suite 600 Seattle, WA 98.104-3855 Date: ,, I; FAX Numberof pages including cover sheet: _J../_ To: e(kf, I --w- -~~e fy;;;_"";-;;n~ Fax: ____j.{]_}'5:)--__ l.f_W Phone:---···--------- From: Cindv Trakels.91L... .WLR Stormwater Services Se::tion Phoue: 206-296-1900 Fax Number: 206-296-0192 IMPORTANT L"EVEL 1 ANALYSIS NOTE: We do not send copies of certai11 complaint tyPes that a.re not relevant such as BCW, Fl, FIR, FrH and WQA, an.cl we do not send CL and LS types. See key below. Type S 1, S2 and S3 will not be faxed due to size constraints. The following is a list of complaint types received by the Water and La:r.d Resources Stom.water Services Section. Complaint numbeni beginning prior to J 990-X.'XXX have been uchived and are no s1 longer in our possession. They cm still be retrieved, if necessary, but will take additional time and may ". not be bene:ficial to your research due to their age, devclopmi:nt which has occurred, etc. If you !ll'e. · int~rested in reviewing the actual complaints, they can be pulled (time permitting) for your revkw. Copies can be obtained for$ .15 pe'l' page, and $2.00 per page for pla:os. Km1 !roe oflpv"sfiHtien C Action Request BCW Bus!ne,3' roraean W~:r cc: R~~PODYC iO lnqairy ~cl Clnim SH Enforci:i.ac:nt l)O Mold ER E1lfbrcc:m.cut Re-v!ti\•r PCC,FCR,FCS Ftoilitr COL"lPlal.n~i. fl SWM Pee 11\qu!ty FL~ SWM Fw Revi,w flH S'w'M Fcs o:i Hold "'1S tawstlit RR Fa.ciiity Bngi11t!oe:-in~ Rc:"itw NDA Neighl,ol.h~od Drnio11&c AsshU!ooc WQC We,tt.r ·q-J.ality Coroplalrii WQB Wucr Q1.:11H~ &lfo.reencm WQ:!-Woter Qw,!lty Bn~riug 11.oview V.'QA Wai~rQuaJ.h)· Audit l"QO WarerQmiiity-Ol!ier S ! ,S2,SN.3 Enshwaing Sl\lcij(& Type of Prnblem DCA DDM Df.S DLE. DTA INQ MM'.~ MMF ~~" . MW.I MNM · !MW SWF WQB WQD. WQI RllM NWD GRT ncvie.101:m11:111t!(.'r::.nstrnctki1~ Dra.11111:e. t1isuli81J.~'JS Drainag:~ -Ero.slo.-JSid!mei1mti01> D1airH1.¥t. -i.Anih:6de'EarU. hk1tmt.1'Jl Dnirt~c-~i:clltib.1 Assi1tanct Dre.ii'1a,cc ·-General hi.quirr Z..fai,1.tcnmi;e • Ae~~btd~ t-{aintc.ntinct -,1o,wri: Maintr:nttn~ -Oen.erL1l Muiotcn?t!Ce, Mowj11g Maint~na.,t~ -Needs MaL1ti::nll1ci Malnt.;n;r.1ce-N:,:do,u W~d£ SWM Fe~ Ques1ir>ns W~tet QuO.:itY• Bes1 Mant.15ttM111 Pr1J.iire~ Wlltel' Quruiiy-Dur:-ipln;; · Water Qu1uity-[tll..:it C.."?t11t(tiO•t sm( f,n .. R,~rurcm'-!1t SWM fe,,-Omu SWJ'v[ Pee-New ni!.:io,un • •¥11-',i\, C, LIJiJl'lf L,4.:,r:• :\Lill.I -..,·.i, 1!t.1\V •-' --·. KlNG COlJNTY WATE~fi"LAND RESOURCES ""VISION'. '' DRA.,iAGE ll'lfVESTIGAT[ON REPv.tlT _, • LJ ' c ' I rv\ rA fv'\ Type (!_ Page I: INV!lST.!OATlON REQl.,"EST PROtlLEM:~/,J:c,;Af=.,£~,...------ Bgg1vEDllY; /, Gg'Trt.e· Date: 7'~tl970K'dby:J7~LENO. '1"1-i r·,cr 'rr .---- Received from: (Eve) ~I -~l NAME:_ 5'7"4c7/6 _s"'koll-l,$ ADDRESS:_L!l_f_Lr,. /_,2 /f:re'? ,U;~ City~~~;.;;_-State W4 Zip o/(J 5'/ Locatiol) of problem, if diffe,ent; _Re_p_o-,t-ed-Pr,-o-bl-em--; ~C-A-LL.~FIRS-T-:;;C::::!:-(-W_o_lll_d L_ike_T_u.:a_e_P_resl!Ilt-. -)---------~--·--·- fi, u ft-1'E \<o-A':) >c-'"Ji(i}J/t#< >c-V~L.. P~ctf"l-5, 4 1-/a,.,,>'£.S ,::,,.J ,µ.,.°),r 911)~ ""r .R'o.110' p,e~p..,,;,e.-ry ~a,.)µ.,,-7. fov-n~ o,,,,. C::,;,y,-r1/,?U.,,..,,IJ...,f ;/"9s ;<t."'-r::r-O A ;g.e-T70....J dl,~ r#E !J1-rc.J,;. ~ . A P/FlAJ ~CcE Accr:¢9 , f'#ar /:'Vtc-rs-0 Y-4 ,_ ,?-tr: . .,f..":i.S /f ;:>, ,n-,,,v J)rn:./.1. CJ,,,.,,.pl.ft,,..,~1-., 7. c;{,_;~~,Je,,O .A-o ,,...,.,,. /2-rev-rt,-1',!!. ,' .,;' _# r. • d)L/ , 1· / , _,/~ ,•' A •r";)..L, LJ io,r , ft'{"(~-.-,,cl,.c,(7 oir/(' _.-,,,,.., D 1·,~e--~.,Pc 1·, /. n. vr.__~ ~· 1 ~ =.., tYI •• . .f.R~ faa-r &,c f/f'oOt't.F ,<!~~,v1~~-r (i,e. ,t';Jca-r hf-t!r. Lot No: Cf Block No: Other agencies involved: No field investiil,tltion requiied ___ _ . . . · (initials) ~····~i-P!! ______ ;J \14 S T R Parcel No. lpl'it{CQ:Oi'l'5_ Ksoll IPC/5W Th.Bros: New..Jfilil F'2, ,.. · Old 42 65 BasixfVIT _ Council District _2_ Charge No. _______ _ ................... -.... , ...................................... ,._ ...................... -.......... _ ... ________ , ......... .-. ..... -. .................................. _.. ........... -......... -~ .............. ______ ~··-~··· .. ,-.... ·~· .......... ~---·--.. ,• RESPONSE: Citizen notified (10 ·----by: _ phone ~ letter __ in person , · ~"'lll 1-it:; s., .. :,-;r .1../.ot!v:$#';,;,:. DISPOSITION: . vYi/+·"2 tf-1&~'t,7 M',,-,Ur- I=edtofl. on ~ / {1~/'. byffiR: Nofurtheractionrecommendedl;,ecause: ___ Lead agency has been notified: __ ·--------------- -Problem has ceen corrected, _ No prnblem ha.5 been id~ntified. __ Prior investigation ;ddre;,;;;-prcblem··- suFIL• # __ _ __ Private problem -NDAP will not considet because: . __ Water originates or.site and/or (ln neighboring parcel. __ Location is outside WLRD Serlice Area, __ Other (Spe.cify): DATE CLOSED: . __ ! __ _,_/ __ By: __ :\l 1\\J \.,\J. 'i\U.V King cou,,ty . \'\-~attn' an.d L~nd Rtiout'Ct:1:, Division. Dcputment o{N1uuro.i Aeeoui'C&.s 700 Fiftn lwtr.\.l.e. Sulte 220V Seattlt, Wo\ 9e104•$02.2 (ZOO') .a96"68:(.9 (JOG) 200..0192 't.,.:t. September 16, 1997 David Gibson 19125 121" Place SB Renton, WA 980S8-7237 'I> *"UI RE: Nctict of King County YiaJation -..s:w:M,DIR 27-1179 Dear l'vf.r. Gibson; On September 2, 1997, Water and Land Resources (WLR) Division 1 staff investigated a drainage problem reported in your neigh,,ornood. Our investigation found t.hal the capacity of the existing storm water facility is being reduced by the installation of the drainage system found in the roadside drainage ditch fronting your property. The drainage ditches were est.ablished to detain and infiltrate as well as convey storm water. Filling in tne ditches may detract from their ability to control the oJnveyance of storm water flows, sending water onto the roadway and your neighbors' proper1ies. This presents a hazard to public safety. You may not be aware that, as property owner, you co1.lld be liable for any personal injury or property damage that resul!A from this c<>nclition. . We recommend that you remove the clom:d-pipe conveyance system found in the roadside ditch !rooting your property to help resolve this condition. This Jetter is not an enforcement action (IT a notification oi violation of King County law. Its puipose is to bring this drainage problem to your attention so you can take action before ii becDmes more serious. If you would lilce more information about this drainage problem, or wouid like _technical assistance in resolving it, please call Jeff Jacobson, WLR Division Lo_cal Drainage Services Unit Engineer, at 296-1953. Thank you for your attention to this matter, CC:JJ:inlllo cc: Glenn Eval'ls, l>.E., Seci.or EngJnec!r, Local Drainage Services Unit 1 Formnly Surface Wattr Managemmt (SWM) Division 11,;i., ~ -' I(.ing County Water and Land.Resource& Divit1fon ::>epr,rh·ncnt ofKarural Ili!Sourcc1 70C Ftf1h !ivcnue, Suite :UOO Sanli, WA 98104:-liOZZ (208) "98-0619 (.206) 200•01$.2 fAX September 16, 1997 GaryVango 19133 121 '' Place Southeast Renton, WA 98058-7237 RE: Notice of King CQllnty Yi2Jation -SWM-DTR 92· J 112 Dear Mr. Vango: On September 2, 1997, Water and Land Resources (WLR) Division' staff investigated a drainage problem reported in your ncighborhood. Our investigation found the capacity of the existing stonn water facility has been reduced !,y the installation of the drainage system found in the olrl roadside ditch system fronting your property. The drainage ditches were established to detain 1111d infiltrate as well as convey storm water. Filling in the ditches detracts from their ability to control the c:onveyance of storm wa.ter flows, sending water onto the roadway and your neighbors' pmperties. This presents a hi\23:rd to public safety. You may not be awate that, as property owner, you could be liable for a.'1.y personal il\iury or property damage that results from this condition. We recommend that you remove the closoo-pipe conveyance system fronting your property and re-establish the drainage ditch system to resolve this condition. This letter is not an enforcement action or a notification of violation of King County law. Its purpose is to bring this drainage problem. 1:0 your attention so you can take action before it becomes more serious. · If you would like more information about this drainage problem, or wo11ld like technical assistance in resolving it, please call Jeff Jacobson, WLR Division Local Drainage Services Unit Engineer, at 296-1953. Thank you for your attention to this matter. £/Ma~·..-,,,0 Curt W. Crawford, P.E., perv!ll Local Drainage Servm nit CC:JJ:lll329 1 cc: Glenn Evans, P .E., Se1lior Engineer, LOC'.al Drainage Services Unit 1 F'omrerly Su,face Water Managemmt (.5'WM) Division . .. .. ··--. --·--~ :\ ! I\\J l.iV, ll''i. l\LI J/ : I ~ KING COUNTY ------------------------, F!LBNO. 9]a1179 I ~ Dapartmant of .Natural Raeourc,;;;;- ~-Water and Land Resource DMtlon ' - NAME STEVE SKOALS .'IDD!lBS3 19113 • 121ST PL SI: I DRAINAGE INVESYIGATION REPORT . FIELD INVESTIGATION PRONE '54-4201 KaOlL PAGE 808W MAlNT. DIVISION _4_ TB FAOE ~~---- DATE -1...-~a~e-~a~--~ l?ffl"IALS • MAM DETAILS OF Ui'VESTlGATION, SITE 'IISIT ON 7-24-87, PROPIRTY OWNER AT to,aS -121'1T PL &l Fil.UNG IN DflAINAGl DITCH WITH 0' PEAP. INVUTIGATION FOUND 101ST PL $E 18 A PRIVATE ROAD WITH AN OPEN DITCH ON THH WHST SID& OF THE STREET. THE PROPERTY OWNER AT 111H 18 IN THE PROClaliS OF l~nALUNC AO' PERF p1pg WITH DRAIN BOXl!S JN TH! DITCH IN PRONT OF THEIR PROPERTY. THE !Xl8T1NQ DRIVEWAY OULV2R'TS ARli 12' CQ~CRETe. FURTHER INVESTIGATION FOUND A CONTl!OL 8TRUCTI/RE WHICH ll!l'IVIC!S THE DRAINAGE DITCH. l'I' APPB,lRS THI PROPaRTY OWNER AT 101H 0 121ST PL SE HAS PILl.l!D IN HIG PORTION OF DITCH WITH o• P~Rf PIPE. PROP!RTY OWN!RS MAY B! A!DUCINQ TH! tTORAOE VOLUME WITHIN THe DtrO~ BY fll.i.JNQ. PHOTO I TAKEN ti I Loo~ING NORTH DOWN 111 ST PL SE. ti • LOOKING AT TH! I PERP PIPE IN8TALLEO BY PROPERTY OWN!R AT HOUS! 18100. fl. $!<OWING INSTALLATION Cf PIP! IN FRONT OF HC)U8i mu. # .f StiOWING IN6TALLATtOH OP,. PeRflll PIPE IN P'RON"'I" OJI House 19US. # t LOOKlNCl SCVTH DOWN 101ST PL ee FROM IN l'HONT OP HOUet: 1,110. SK6TCR "fOUS! p,,...;...;...;;;&ie!:lj ~Q'IJ,3 CCNTAOL STA1.1CTIJRE SE 192ND ST , L_. ·-----··--· . _____ J !\~1\\1 \.V, f!Ll\•J II V1 .II, , I -·-·--... -- ,. N!!IGIIBOIUIOOI> l>RAIIIIA.QB l1$SIS'l'ANC!I l'~ COIIPJ:.AI!IAll't' l!VllllA'l'l:Ol( XBIIIO TO: FILE •'ROM: .Jlii'i' .JACO!lSON RE: ENQlNEERlNG EVALUATION FOR :OMPIJ.:INT NO. 97•ll79; Skoals COMPLAINT CHRONOLOGY: ORIGWJIL: FIELD INV: l"IELD E\7AL: OLD FI:.:JlS , BACICGR01lNI): ?/21/97 7/24/97 9/03/97 N/A The complainant lives al"'1!, a private roadway par~ of Short !>lat 8790B2. Th@ original draizlage plans for the short plat show t:he open ditch system on the west side of 121st Place SE was designed for infiltration/retention as well a!i conveyance. The open ditch conveys runoff to a coatrol struoture loi,ated at the intersection ot 121st E'laoe SE and SE 192n Street. The op~l ditches have l2-inch driveway culverts located intermittently; oonnaotiltS them to one another. The complaitant: is concerru,d with the recent development u.: the area ami t~ intrusion upon the ,,pen ditch syste:n. :t.aet year 1:he ~~sident at 19133 1218 t: Plaaa SE filled in the open ditch fronting the property as part of their detach,od garage addition. A e-inch pertorated conveyance pipe was i:,stallad before the ditch was filled. According to the oomplai:iant surfacft 14tar.from the open ditcb.ae overt<>pped c:he roadway and flowed ~ast affectill.!r the residents living en tne east side of l~lst Place SE. Thie·attnll!Ufr t:be residents at 1Sl2S 121•t Place SE are filling in tneir open dit<'h ,rbil" adding a 6•inch perforated convtaya~oe. line connected by a sories of lawn dr~ins as part of their detached garage corustruction. The complainant believes the integrity of the drainage syate:n will be severely oornpromis9d and futu,·e floodins ma.y result from these act!vities. ll'DIDIIIGS: Since the problem meets all of th, N01\P project criteria li8tecl below. it qualifies for iUld has been Ln1•estigated u.-,der the NDAP program. • The problem site is within the SWM service a:z::·~a and deea not involve a King County (KC) code violation. 1 "I.'", I\, (.;, LI),} I ~:iiffam·· .• , , :.. . ') ! r :v ,\JI\IJ \J'J, r.l/\V • Tlie problem site shows evidence of or reported lo~alized flooding, erosion and;,,r Qedimer,tation · lfithin the off road drai11asre system on prhate r"'sid.tmtiail and/or comm,n:cinl pi-operty due to later ·upstream de•relopment. • l'ne problem is eaused ey surface wate,· from more than one ad~oining property. son,s: Ac,;,ording to t:he KC soils ma;,, the "ite is located in che following soil association, r'. At.PSltWOOP ASSOCIAnou, Moderately well drained undulating co hilly "oils that have dense, v•ry slowly p<>rmeahle glacial till.at a·aepth of 20 to 40 inches; on uplands and terraces. OPT10NS A:111) P~SCUSSION, 1. ~ enfoteeir.ent letter Cilll be sent to the aforementioned resid.,,1te who fJ.lled L'1 th.e open citch ey .• t..m. l'he latter "1111 aek for their coope:,;atl.o.i in removing the conveyarioe systems &o tlle. open d'..tohes can he reseo1·e.d to function as dee igned, Jl.n enforceme..'11: lootter will he e~t. l!Jli'OltCEl!ENT PRIORlTY acoRE ~ 40 2 /_,,' .'· : I '""'' C:, l'!O ''' ! '''lNG l" ""-"' '"·'"ER AND LAND RESOU:RCEsJ)1VJs1;'.;'.~ ~' i 1 r. ,1/ i _i-a.47 DRA .'AGE .ll\JVESTIGATION REPCh<T fVI A fV\ . Page I: INVESTlOATION REQU'EST Type e l'ROBLID,,/;; l)&4:/f.\M..,G',..i;;;;-'" ___ _ &cEIVEQE:.._L_6' ii'7"Zke-Dat~~(si 7 OK'd by: "D{l,terfou: No, 9·1-13 o I Received from: N A."1B; A r., chu :,'...,, dy,S_ (Day) L..._} (Eve) !.~.....! PHONE~....;.~--~-- ADDRESS:_· ·---------City~...J StateW.A Zip ?f)()Sf Location of problem, if different: lo t..,5. l'' I .IJL. C"'...f:', (r>(J..'hd. c. (C7;.t:,:,<>11 I·-·-=--..:..:·--~* ,r.,____,v_--=-..;;-'= '-;...:..i..-=---,----,----- Reported Probtem: CALLFIRST D (WouldLikeToBePresem) °Rft..n"h.n q8o5!!,'7Z'!"7 ~~ ($_./e,,,,.,.-J',IO..r-r" ?"Y-9-r ,fr ~ (,,,:/,e ,; ~ d s:"r-,N"' E'. · AM:> is Fii ,./.f-f'"r::. LotNo: <f Block No: Other agencies involved: 9 ~ _ rx' No field investigation requirlld __ _ ,'I' (initials) -2!.J.. ?,3 ~ 6 'l4 S T R Parcel No. {p J4 'J(!p ~~ Kroll ko5 W Th.Bros: New Old Basin '3()0 Council District .::_L Charge No. ' • ~•• ••·--,•o,•••,,,, ................. •••• ·---··-'"" .............................. , ...... ,. __ , __ •~•••'"" _ ............ ,_•--•-··-·•~ ""'" .......... ~••••••-••• --··-• ._ ... ,.,•,-m-•n•-•-•_.,,,,., •• ,__, ...... <0-HYOM••-••••·•-•••' •-•• ·-••••••••··• R.t':SPONSE: Citiz~n notified on ---~--by: _ phone _;__ __ letter __ in person Co...-pl..v.1,.H .. C'.1,...ClS.:;:t, To '1'1-Ill~ NI) ZNV'c;'4'Tl'6,l't1-/0N l<ca..t.Ul<,.«::{), DISPOSITION: Turned to -on l I by_ OR: No further action recommended becaust··. ___ Lead agency has been notified: ------- -·-Problem has 1:ieen corrected. _ No pro bf om has been identified .. _ Prior inves,...Jilion addres~es probl~m: . ~~~v~~ __ Private problem • NDAJ' will not coru,lder because: · __ Watex originates onsite and/or on neighboring parcel. Location is outside WLRD S~!J'!l __ Other (Specify): DATE CLOSEl>: 2 I t I f' 7 By: J'!? )~97-//?f} i' j / : ! ···--... __ : ·-------- KING COUNTY PIU!NO. 97•1301 .,..-=-----------Department of Natural Ruourcea NA.ME ANONYMOUS .--------.../ Water and Land Resource Dlvl••lon DRAINAGE INVESTIGATION REPORT FIELD INVESTIGATION ADDRESS 18125 :._ 121ST PL ~·"'---I PHONE T.BPAGE ~6~B6~--F2=-~-~ KROU, PAGE eo&W MAINT. DIVlSION _--4._ DATB 7 .... 7 =IALS·· MAM DE'I'A!LS OF INVES'OOATION: . ~· I Sile 1/i&IT ON 7•24-07. PROP&RTYCWNER AT 19121 • 12111T PL SE flWNQ JN DRAINAOe DITCH WITH o• PERF.. Qd ! 1NVESTitliATION fOUND 1018T l'L SK IS A PRIVATE ROAD W17H AN OP~N DITCH ON Tl-IE WE;ST $IC& Of THE STREET. 1'1 i 'rHe PROPHTY OWNER AT U1211S IN THE PIIOC:IISS OF INSTAWNG AO' P&RF PIP& WITH DRAIN eons IN THE i DITCH IN FRONT OF THEIR PROPERTY. ·rHe fXISTING ORI\IEWAY CULVllR1'8 ARE 11" OONCRETt. FURTHER . ! INVESTIGATION FOUND A CONTRCII. STRUOTURI WHICH !IERYIOES TH! ORAINAIIE DffCH. IT AFPIIARS THE PROPERTY OWNER AT 1911$ • -,~,n PL SI HA$ FILL!ill IN HIS PCIIITION OF nJTCll WITH •• PSAP PIPE. PROPERTY OWNERS MA¥ BE REPUCIN!i THE ST0RAl1! VOLUMS WITHIN THE Dll'CH BY l'ILUNQ. SKETCH: COMPLAINT CLC)SED TO 97-1179 HOl1ee 1'113 1~100 gl ~ . . ' I w (I) it t; ... C\I ... ---1> SE 192ND ST ----------------I ___________________ ______J t. i1)~i l ?Lt'IV i",,:1\\,1 \,,l1• 'flLI\V -!N, Ji,: ·"J -. KING 1...,v•:;,,r:v '" ATER AND LAND RESOURCE'" •!VISION lOJkfNAGE INVESTIGATION REPORT 'tv~?ij-~ PROBLEM: @Jtvl+G€ REc,8MIDBY: t!. G1,-TTl-1::t Pase 1: INvl!.lT!OATIONIU!QUF.~T Type C Date· !.;/d_fJ-~ OK'dby: D~-"FlL:tNo. fJ-9.2cb Other agencies involved: No field investigation required'--- BIi fiU. SIi,/ ...M. ~ _,i_ \4 S . T R Parcel No. (qlf'Ja()iJJ ,{O Kroll fo(J5uJ Th.Bros New_ ~g~ fJ.1£2 <'M Old 'f,1/TJ;J5 Basin~ Counci1Distriot_l_ ChargeNo. ______ ...;.._ 'RESPONSE; Citizen notiiied on 1-1 ~ ~9 9 by: _ phone __ letter -~ in person '-Fr C,,1z.cw Jr4;w $".1,.1c,~ &hrf, ~r::cit>~ ~ .f¥1?y '11-PS~P l?N"P R~ti'¢t ~. /?e,,,.11>.1 P1111~1G.1-1 r, e1111tA· P.<f'liMl4'1c ();.I sf 111.-.t~sr Ft;;tt, :/31.()e,/!/ld, "t. DISPosrnoN: Turned to __ on _L._ by __ OR: No further action rc,;ommended because: ){L Lead agency has been notified: fu /N:;> :, .ti1.1J /VI 01 t/.._4-______ _ __ . _ Problem has been C-Ol'l'CCted. _. _ No problem has beeo identified. _ Prior investigaticn addresses problem: __ ...:._ Private problem -NDAP will not consider because: SUFI!.111 --- __ Water originates onsite and/or on neighboring parcel. Locaticn is outside WLJU> Sen~~· ____ Other (Specify): DATECLOSED: / / iJ't/'19 By: _:__g_J ~/f¥if~j)f ,.,,.,1\, 1.,., L •.I J I · i. . ')I.; Ii' ;\ l I\ \1 \.I IJ, W L KU --~----,,,.,...,...,..-----------·-~·-···:". ..... -NO. 3215 .. -.. 0 , l .. , • p '/ ' 1_~f*Z.,.:, ;..__,.,.. .. . ·~:~·..-'•····· r·---, ~ . ;~ .. J ~ KrNG CoUNTY _ J \ A Q Cepattment of Natural Reaour,)e11 Fll..E NO. _,9...,8..._•_.,0...,9~2~6,__ ______ ~--~ NAME GARV VANGO I I DRAINA;;t~~:;~;~::;,~~o :;;:~~T I ADDRESS 19133 • 1218T PL SE ·---i TB PAGE llH•F2 j DA1'E 1 ·22·99 --1 JNIT!ALS • MAM PHONE l2S3}8S4•2649 KROLL PAGE 806W MAIN1'. OlVISION .J__ 1 FIELD INVESTIGATION I DETAILS OF INVESTIGATION: ~ Sl'rE VISIT ON 1-12•11. STAHT DRAINAGE 8L.OCKEC C~U81NGJ ORAINA<IE SYSTEM ON PRIVATE RCAC TO SAC~ UR ti.I INVESTIGATION FOUND TM! oaAINAGE 6Y6TEl\'J ON 121 !IT ~L 8! HAS A CON~OL STRUCTURE WHICH DRAINS TO A l'(J CATCH BASIN IN THE ROAO RIGHT•OF,WAY. THE SLIDE OATF. FOR T>1e SYSTEM WAS OPEN WHICH ALLOWS FOR WATER NT' TO FLOW INTO SYll'rl!M FROM S'llle&T CATCfl BASIN. CLOseo SL.ICE QATE AT THIS TIME. IN8PEOTiD STA&ET > DRAINAGE ON se ,e.No BT JUS1 ~AST OF i016T PL SI POA ANY IILOCKAQE. WHEN LINE WAS CANDLED LIGHT ReFLECTeD BACK. THERE APPEARS TO ae A METAL OIIJ!OT ABOUT SO' DOWN THI LINB. TALKED TO COMPLAINANT 11 WAS SUOGESTED suoe. GATilf: 8! l(EPi CL.OBED TO F1RIV!NT A BACK WASH INTO PFUYA'TE SYSTIM, MENTlON'EO A MEMO WO~LD Bt SENT TO ROADS TO HAW TH!M INV!STlllATI OBJBCT IN PIPE. NO PHOTOS TAKEN SKETCH: HQ1JH ""' w Cl) ..I A. t; -c,i ... -===========:::::!~7----'~+=====::==::==:=:::::!~D-i> QA~L!lt> PIPl!I NO'T'EO 80118 T'IP'I! 01" 01,,QCM.Qle SE 192ND ST LIGHT FIIIP~C,Til:D E)ACM; ------ I i I I ' ... , I i I I j I _______ _J TASK 3 FIELD INSPECTION TASK 3 FIELD INSPECTION A field inspection was conducted on March 6, 2007, to inspect the onsite drainage system of the site. Offsite drainage systems were also inspected downstream approximately 1/4 mile(s) from the discharge point of the site. The inspection involved investigation of the ten specific items of a Level 1 Inspection per the King County Surface Water Design Manual, 2005. The inspection yielded the following findings: 1. There were no existing or potential problems observed. 2. The existing drainage system capacity was adequate. 3. There were no existing or potential flooding problems. 4. There were no existing or potential sedimentation, scouring or bank sloughing problems. 5. No significant destruction of aquatic habitat or organisms was noticeable. 6. Qualitative data such as land use, impervious surfaces, topography, and soil types was noted and can be found in Task 4 information. 7. Information was collected on pipes, ditches, and structures. This information is also included in the Task 4 information. 8. Tributary basins delineated in Task 1 were verified. 9. No neighbors were contacted. 10. The weather conditions at the time of the inspection were sunny and mild. TASK 4 DRAINAGE SYSTEM DESCRIPTION AND PROBLEM DESCRIPTIONS TASK 4 DRAINAGE SYSTEM DESCRIPTION AND PROBLEM DESCRIPTIONS Site Drainage This project is located at 19029 120th Ave SE in Renton, Washington. The property is approximately 2.14 acres. We are proposing that the property be divided into nine residential lots, along with a drainage and recreation tract. Some of the lots will gain access directly from the new road to the south of the property, (Road A). The rest of the lots will gain access from JUD Tracts connected to Road A The prope'rty has an existing home, garage, and concrete pathways, all of which will be removed. The existing house has a few bushes nearby, along with lots of grass, extending to the east property line. West of the existing buildings there is virtually no vegetation due to recent clearing and grading activity. The existing site drainage mainly sheet flows from the north to the south. There are approximately 3 acres of upstream area that flow to the site. We will plan to allow this flow to bypass our site by providing a separate system for conveyance. Soils on this site consist of Alderwood gravely sandy loam, 0 to 6 percent slope (AgB). Offsite Drainage Off-Site Analysis Drainage System Tables are provided on the following pages that describe in detail the offsite drainage components at least Y. mile downstream from the project discharge locations. Please refer to the offsite drainage map in Task 1 because the map symbols listed in the tables correspond to drainage component symbols on the offsite drainage map. (*) = SEE PHOTO Basin: SOOS CREEK Symbol Drainage Component Type, Name, and Size see map Type: sheet flow, swale, stream, channel, pipe, pond; Size: diameter,_ surface area Al 12" CPP w/CB's A2 24" CPP w/CB's A3 18" CPP w/CB + A4 18" CPP w CB's AS 18" CPP w/CB's A6 18" Cone. w CB's A7 18" Cone. w/CB's AS Half 24" Cone. pipe A9 Stream channel 98-4\inB04 OFF-SITE ANALYSIS DRAINAGE SYSTEM 1l'ABLE SURFACE WATER DESIGN MANUAL, CORE REQUIREMENT #2 Subbasin Name: Subbasin Number: Drainage Slope Distance Existing Potential Observations of field Component from site Problems Problems inspector, resource Description discharae reviewer, or resident drainage basin, vegetation, % Y. ml = 1,320 ft. constrictions, under capacity, ponding, tributary area, likelihood of problem, cover, depth, type of sensitive overtopping, flooding, habitat or organism overflow pathways, potential impacts area, volume destruction, scouring, bank sloughing, sedimentation, incision, other erosion Flows south 2.2 0-24' None None No problems observed (*) Flows east to pond 1.6 24'-344' None None No problems observed (*) Pond to control CB NIA 344'-544' None None No problems observed (*) Flows southeast 1.9 544'-585' None None No problems observed (*) Flows south 1.1 585'-893' None None No problems observed (*) Flows east 3.6 893'-1,363' None None No problems observed Flows east 9.4 l,363'-2,013' None None No problems observed (*) Flows east 20 2,013-2,113' None None Ivy over, but free flow (*) 3' to 5' wide, brush 15 2,l 13'-2,183' None None No problems observed (*) (*) = SEE PHOTO Basin: SOOS CREEK Symbol Drainage Component Type, Name, and Size see map Type: sheet flow, swale, stream, channel, pipe, pond; Size: diameter, surface area Bl 12" CPP w/CB B2 12" CPP w/CB's AS 18" CPP w/CB's A6 18" Cone. w CB's A7 18" Cone. w/CB' s AS Half24" Cone. pipe A9 Stream channel 98-4\inB04 OFF-SITE ANALYSIS DRAINAGE SYSTEM TABLE SURFACE WATER DESIGN MANUAL, CORE REQUIREMENT #2 Subbasin Name: Subbasin Number: Drainage Slope Distance Existing Potential Observations of field Component from site Problems Problems inspector, resource Description discharae reviewer, or resident drainage basin, vegetation, % Y. ml= 1,320 ft constrictions, under capacity, ponding, tributary area, likelihood of problem, cover, depth, type of sensitive overtopping, flooding, habitat or organism overflow pathways, potential impacts area, volume destruction, scouring, bank sloughing, sedimentation incision, other erosion Flows south 20 0-21' None None No problems observed Flows south 1.9 21 '-177' None None No problems observed (*) Flows south I. I l 77'-485' None None No problems observed (*) Flows east 3.6 485'-955' None None No problems observed Flows east 9.4 955'-1,605' None None No problems observed (*) Flows east 20 1,605-1,705' None None Ivy over, but free flow(*) 3' to 5' wide, brush 15 1,705'-1,775' None None No problems observed (*) Pictures showing some of the downstream from the Bob Singh Plat. CB (End of A1 at top, beginning of A2. to the right) Top of picture is towards the north. CB, top of picture is towards the west. The end of A4 is shown in the upper right. The end of 82 is partially visible in the bottom right, and the beginning of AS is shown on the left. Top of picture is towards the east. In the foreground is A8 covered in Ivy. Beyond is A9. TASK 5 MITIGATION OF EXISTING OR POTENTIAL PROBLEMS TASK 5 MITIGATION OF EXISTING OR POTENTIAL PROBLEMS After a thorough field inspection and a detailed resource review there were no existing or potential problems. The proposed improvements will not produce a significant impact to the existing drainage patterns once the site has been stabilized and the runoff has been controlled via a combined detention-wet vault. A temporary erosion and sedimentation control plan will be created at the final design stage to minimize the transport of sediment laden runoff to the downstream conveyance system. APPENDIX THRESHOLD ASSESSMENT AND PRELIMINARY CALCULATIONS THRESHOLD ASSESSMENT The below figures represent the impervious surface calculations for this project. Notice that the figures have accounted for future development (13 lots). Net new impervious surface onsite: 13 new homes & driveways @ 2500 each Frontage improvements Joint Use driveways and other onsite improvements Less existing impervious being removed Total 32,500 sf 2,500 sf 7,348 sf -3.503 sf 38,845 sf Per Section 1.1.2, this project qualifies for Full Drainage Review. Both water quality and flow control facilities are required. A combined detention/wet vault will be provided for this project for both flow control and water quality. PREDEVELOPED FLOWS -Land Use Sununary Till Forest 2.20 acres Till Pasture o.oo acres Till Grass 0.00 acres Outwash Forest 0.00 acres Outwash Pasture 0.00 acres Outwash Grass o.oo acres Wetland 0.00 acres Impervious 0.00 acres Total Area : 2.20 acres Scale Factor : 1. 00 Hourly Reduced Time Series: predev Compute Time Series Modify User Input Flow Frequency Analysis Time Series File:predev.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak -Peaks Rank Return Prob (CFS) (CFS) Period 0.139 2 2/09/01 18:00 0.178 1 100.00 0.990 0.037 7 1/06/02 3:00 0.139 2 25.00 o. 960 0.103 4 2/28/03 3:00 0.107 3 10.00 0.900 0.004 8 3/24/04 20:00 0.103 4 5.00 0.800 0.061 6 1/05/05 8:00 0.090 5 3.00 0.667 0.107 3 1/18/06 21:00 0.061 6 2.00 0.500 0.090 5 11/24/06 4:00 0.037 7 1.30 0.231 0.178 1 1/09/08 9:00 0.004 8 1.10 0.091 Computed Peaks 0.165 50.00 0.980 DEVELOPED FLOWS -Lan d Use Summary Till Forest o.oo acres Till Pasture o.oo acres Till Grass 1.23 acres Outwash Forest 0.00 acres Outwash Pasture o.oo acres Outwash Grass 0.00 acres Wetland 0.00 acres Impervious 0.97 acres Total Area : 2.20 acres Scale Factor : 1.00 Hourly Reduced Time Series: dev Compute Time Series Modify User Input Flow Frequency Analysis Time Series File:dev.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak -Peaks Rank Return Prob (CFS) (CFS) Period 0.345 5 2/09/01 2:00 o. 719 1 100.00 0.990 0.263 8 1/05/02 16:00 0.419 2 25.00 0.960 0.419 2 2/27/03 7:00 0.384 3 10.00 0.900 0.265 7 8/26/04 2:00 0.364 4 5.00 0.800 0.324 6 10/28/04 16:00 0.345 5 3.00 0.667 o. 364 4 1/18/06 16:00 0.324 6 2.00 0.500 0.384 3 10/26/06 0:00 0.265 7 1. 30 0.231 o. 719 1 1/09/08 6:00 0.263 8 1.10 0. 091 Computed Peaks 0.619 50.00 0.980 Retention/Detention Facility Type of Facility: Facility Length: Facility Width: Facility Area: Effective Storage Depth: Stage O Elevation: Detention vault 76.75 ft 76.75 ft 5890. sq. ft 4.00 ft 499.46 ft Storage Volume: Riser Head: 23561. PROVIDED 120'X50'X4'=24,000 CF 4. 00 ft Riser Diameter: 12.00 inches Number of orifices: Orifice # 1 2 Height (ft) 0.00 3.00 2 Diameter (in) 0.87 2.25 Top Notch Weir: None Outflow Rating Curve: None Full Head Discharge (CFS) 0.041 0.137 Pipe Diameter (in) 6.0 Stage (ft) o.oo 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.17 0.27 0.37 0.47 0.57 0.67 0. 77 0.87 0.97 1. 07 1.17 1.27 1. 37 1. 47 1. 57 1. 67 1. 77 1. 87 Elevation Storage Discharge Percolation (cfs) 1. 97 2. 07 2 .17 2.27 (ft) 499.46 499.47 499.48 499.49 499.50 499.51 499.52 499.53 499.63 499.73 499.83 499.93 500.03 500.13 500.23 500.33 500.43 500.53 500.63 500.73 500.83 500.93 501.03 501.13 501.23 501.33 501. 43 501. 53 501.63 501. 7 3 (cu. ft) 0. 59. 118. 177. 236. 295. 353. 412. 1001. 1590. 2179. 2768. 3358. 3947. 4536. 5125. 5714. 6303. 6892. 7481. 8070. 8659. 9248. 9837. 10426. 11015. 11604. 12193. 12782. 13371. (ac-ft) 0.000 0.001 0.003 0.004 0.005 0.007 0.008 0.009 0.023 0.037 0.050 0.064 0.077 o. 091 0.104 0.118 0.131 0.145 0.158 0.172 0.185 0.199 0.212 0.226 0.239 0.253 0.266 0.280 0.293 0.307 (cfs) 0.000 0.002 0.003 0.003 0.004 0.005 0.005 0.006 0.009 0. 011 0.013 0.014 0.016 0. 017 0.018 0.019 0.020 0.021 0.022 o. 023 0.024 0.025 0. 026 0.027 0.027 0.028 0.029 0.030 0.030 0.031 o.oo 0.00 0.00 0.00 0.00 0.00 o.oo 0.00 0.00 o.oo 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 o.oo 0.00 0.00 o.oo 0.00 0.00 0.00 0.00 2.37 501.83 13960. 0.320 0.032 0.00 2.47 501.93 14549. 0.334 0.032 0.00 2.57 502.03 15138. 0.348 0.033 0.00 2.67 502.13 15727. 0.361 0.034 0.00 2. 77 502.23 16316. 0.375 0.034 0.00 2.87 502.33 16905. 0.388 0.035 o.oo 2.97 502.43 17494. 0.402 0.035 0.00 3.00 502.46 17671. 0.406 0.036 0.00 3.02 502.48 17789. 0.408 0.037 o.oo 3.05 502.51 17965. 0.412 0. 041 0.00 3.07 502.53 18083. 0.415 0.048 0.00 3.09 502.55 18201. 0.418 0.057 0.00 3.12 502.58 18378. 0.422 0.068 0.00 3.14 502.60 18496. 0.425 0.081 0.00 3.16 502. 62 18613. 0.427 0.092 0.00 3.19 502.65 18790. 0.431 0.096 0.00 3.21 502. 67 18908. 0.434 0.100 0.00 3.31 502.77 19497. 0.448 0.114 0.00 3.41 502.87 20086. 0.461 0.126 0.00 3.51 502.97 2067 5. 0.475 0.136 0.00 3.61 503.07 21264. 0.488 0.146 0.00 3. 71 503.17 21853. 0.502 0.155 0.00 3.81 503.27 22442. 0.515 0.163 0.00 3.91 503.37 23031. 0.529 0.171 0.00 4.00 503. 46 23561. 0.541 0.178 0.00 4.10 503.56 24150. 0.554 0.493 0.00 4.20 503.66 24739. 0.568 1. 060 0.00 4.30 503.76 25328. 0.581 1. 800 0.00 4.40 503. 86 25917. 0.595 2.600 0.00 4.50 503.96 26506. 0.609 2.890 o.oo 4.60 504.06 27095. 0.622 3.150 0.00 4.70 504.16 27684. 0.636 3.390 0.00 4.80 504.26 28273. 0. 649 3.610 o.oo 4.90 504.36 28862. 0.663 3.820 0.00 5.00 504.46 29451. 0. 676 4.020 0.00 5.10 504.56 30040. 0.690 4.210 0.00 5.20 504.66 30629. 0.703 4.390 o.oo 5.30 504. 76 31219. o. 717 4.570 o.oo 5.40 504.86 31808. 0.730 4.730 0.00 5.50 504.96 32397. 0.744 4.900 0.00 5.60 505.06 32986. 0.757 5.050 o.oo 5.70 505.16 33575. 0.771 5.210 0.00 5.80 505.26 34164. 0.784 5.350 0.00 5.90 505.36 34753. 0.798 5.500 o.oo 6.00 505. 4 6 35342. 0. 811 5.640 0.00 Hyd Inflow Outflow Peak Storage Target Cale Stage Elev (Cu-Ft) (Ac-Ft) 1 0. 72 0.18 0.18 4.00 503.46 23545. 0.541 2 0.35 ******* 0.15 3.65 503. 11 21483. 0.493 3 0.42 ******* 0.13 3.42 502.88 20169. 0.463 4 0.34 ******* 0.09 3.16 502.62 18632. 0.428 5 0.36 ******* 0.03 2. 85 502.31 16779. 0.385 6 0.21 ******* 0.03 2.37 501. 83 13953. 0. 320 7 0.26 ******* 0.03 1. 92 501.38 11291. 0.259 8 0.26 ******* 0.02 1.12 500.58 6601. 0.152 WETPOND CALCULATIONS The following calculation is per Section 6.4.1 of the KCSWDM. Runoff Volume= Vr = (0.9Ai + 0.25Atg + O.lOAtf + O.OlAo) x (R/12) Ai=42400 sf Atg=53560 sf Atf=O Ao=O R=. 47 Vr = [ (0.9) (42400)+(0.25) (53560)+0+0] X (.47/12) Wetpool Volume Vb= f(Vr) f=3 Vr=2019 cf Vb= 3x2019 = 6057 cf 2019 cf Wetpool volume= 13'xl20'x4.0' = 6240 cf, thus satisfying the volume required. APPENDIX B DETENTION AND WATER QUALITY CALCULATIONS PREDEVELOPED FLOWS ~Land Use Swnrnary Till Forest 2.20 acres Till Pasture 0.00 acres Till Grass 0.00 acres Outwash Forest 0.00 acres Outwash Pasture 0.00 acres Outwash Grass 0.00 acres Wetland 0.00 acres Impervious 0.00 acres Total Area : 2.20 acres Scale Factor : 1.00 Hourly Reduced Time Series: predev Compute Time Series Modify User Input Flow Frequency Analysis Time Series File:predev.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak -Peaks Rank Return Prob (CFS) (CFS) Period 0.139 2 2/09/01 18:00 0.178 1 100.00 0.990 0.037 7 1/06/02 3:00 0.139 2 25.00 0. 960 0.103 4 2/28/03 3:00 0.107 3 10.00 0.900 0.004 8 3/24/04 20:00 0.103 4 5.00 0.800 0.061 6 1/05/05 8:00 0.090 5 3.00 0.667 0.107 3 1/18/06 21:00 0.061 6 2.00 0.500 0.090 5 11/24/06 4:00 0.037 7 1.30 0.231 0.178 1 1/09/08 9:00 0.004 8 1.10 0.091 Computed Peaks 0.165 50.00 0.980 DEVELOPED FLOWS -Land Use Summary Till Forest 0.00 acres Till Pasture 0.00 acres Till Grass 1.23 acres Outwash Forest 0.00 acres Outwash Pasture 0.00 acres Outwash Grass o.oo acres Wetland 0.00 acres Impervious 0.97 acres Total Area : 2.20 acres Scale Factor : 1.00 Hourly Reduced Time Series: dev Compute Time Series Modify User Input Flow Frequency Analysis Time Series File:dev.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak -Peaks Rank Return Prob (CFS) (CFS) Period 0.345 5 2/09/01 2:00 0. 719 1 100.00 0.990 0.263 8 1/05/02 16:00 0.419 2 25.00 0.960 o. 419 2 2/27/03 7:00 0.384 3 10.00 0.900 0. 265 7 8/26/04 2:00 0.364 4 5.00 0.800 0.324 6 10/28/04 16:00 0.345 5 3.00 0.667 0.364 4 1/18/06 16:00 0.324 6 2.00 0.500 0.384 3 10/26/06 0:00 0.265 7 1.30 0.231 0.719 1 1/09/08 6:00 0.263 8 1.10 0.091 Computed Peaks 0.619 50.00 0.980 Retention/Detention Facility Type of Facility: Facility Length: Facility Width: Facility Area: Effective Storage Depth: Stage O Elevation: Storage Volume: Riser Head: Riser Diameter: Number of orifices: Detention Vault 120.00 ft 50.00 ft 6000. sq. ft 4. 00 ft o.oo ft 24000. cu. ft 4. 00 ft 12.00 inches 2 Full Head Pipe Orifice 11 Height Diameter Discharge Diameter (ft) (in) (CFS) (in) 1 o.oo 0.84 0.038 2 2.40 1. 45 0. 072 4.0 Top Notch Weir: None Outflow Rating Curve: None Stage Elevation Storage Discharge Percolation (ft) (ft) (cu. ft) (ac-ft) (cfs) (cfs) o.oo 0.00 o. 0.000 0.000 0.00 0.01 0.01 60. 0.001 0.002 o.oo 0.02 0.02 120. 0.003 0.003 o.oo 0.03 0.03 180. 0.004 0.003 o.oo 0.04 0.04 240. 0.006 0.004 0.00 0.05 0.05 300. 0.007 0.004 o.oo 0.06 0.06 360. 0.008 0.005 0.00 0.07 0.07 420. 0.010 0.005 o.oo 0.17 0.17 1020. 0.023 0.008 o.oo 0.27 0.27 1620. 0.037 0.010 0.00 0.37 0.37 2220. 0.051 0.012 o.oo 0.47 0.47 2820. 0.065 0.013 0.00 0.57 0.57 3420. 0.079 0.014 0.00 0.67 0. 67 4020. 0.092 0.016 0.00 0.77 0. 77 4620. 0.106 0.017 0.00 0.87 0.87 5220. 0.120 0.018 o.oo 0.97 0.97 5820. 0.134 0.019 o.oo 1. 07 1. 07 6420. 0.147 0.020 o.oo 1.17 1.17 7020. 0.161 0.021 0.00 1.27 1.27 7620. 0.175 0.022 0.00 1. 37 1. 37 8220. 0.189 0.022 0.00 1. 47 1.47 8820. 0.202 0.023 0.00 1. 57 1.57 9420. 0.216 0.024 0.00 1. 67 1. 67 10020. 0.230 0.025 0.00 1. 77 1. 77 10620. 0.244 0.025 o.oo 1. 87 1. 87 11220. 0.258 0. 026 0.00 1.97 1.97 11820. 0.271 0.027 o.oo 2. 07 2.07 12420. 0.285 0.028 o.oo 2.17 2.17 13020. 0.299 0.028 0.00 2.27 2.27 13620. 0.313 0.029 o.oo 2.37 2.37 14220. 0. 326 0.029 0.00 2.40 2 .40 144 00. 0.331 0.030 o.oo 2.42 2.42 14520. 2.43 2.43 14580. 2.45 2.45 14700. 2.46 2. 46 14760. 2.48 2.48 14880. 2.49 2.49 14940. 2.51 2.51 15060. 2.52 2.52 15120. 2.54 2. 54 15240. 2. 64 2. 64 15840. 2.74 2.74 16440. 2.84 2.84 17040. 2.94 2.94 17640. 3. 04 3.04 18240. 3.14 3.14 18840. 3.24 3.24 19440. 3.34 3.34 20040. 3.44 3.44 20640. 3.54 3.54 21240. 3. 64 3. 64 21840. 3.74 3.74 22440. 3.84 3.84 23040. 3.94 3.94 23640. 4.00 4,00 24000. 4.10 4.10 24600. 4.20 4.20 25200. 4.30 4.30 25800. Hyd Inflow Outflow Peak Target Cale Stage 1 0. 72 0.18 0.22 4. 04 2 0.42 ******* 0.09 3.23 3 0.38 ******* 0.03 1. 80 4 0.36 ******* 0.06 2.61 5 0.34 ******* 0.10 3.73 6 0.32 ******* 0.02 0.87 7 0.26 *"'***** 0.02 1.14 8 0.26 ******* 0.03 2.05 Route Time Series through Facility Inflow Time Series File:dev.tsf Outflow Time Series File:rdout Inflow/Outflow Analysis Peak Inflow Discharge: 0. 718 Peak Outflow Discharge: 0.221 Peak Reservoir Stage: 4.04 Peak Reservoir Elev: 4.04 Peak Reservoir Storage: 24213. 0.556 0.333 0.030 o.oo 0.335 0.031 o.oo 0.337 0.034 0.00 0.339 0.037 o.oo 0.342 0.041 0.00 0.343 0.046 0.00 0.346 0.049 0.00 0.347 0.050 o.oo 0.350 0.052 0.00 0.364 0.059 0.00 0.377 0.065 0.00 0.391 0.070 o.oo 0.405 0.075 0.00 0.419 0.079 o.oo 0.433 0.083 o.oo 0; 44 6 0.087 o.oo 0.460 0.090 0.00 0.474 0.094 0.00 0.488 0.097 0.00 0.501 0.100 0.00 0.515 0.103 0.00 0.529 0.106 o.oo 0.543 0.109 0.00 0.551 O. llO o.oo 0.565 0.421 0.00 0.579 0.987 0.00 0.592 1. 720 0.00 Storage Elev (Cu-Ft) (Ac-Ft) 4.04 24213. 0.556 3.23 19404. 0.445 1. 80 10820. 0.248 2.61 15687. 0.360 3.73 22379. 0.514 0.87 5248. 0.120 1.14 6826. 0.157 2.05 12290. 0.282 CFS at 6:00 on Jan 9 in Year 8 CFS at ll: 00 on Jan 9 in Year 8 Ft Ft Cu-Ft Ac-Ft Flow Duration from Time Series File:rdout.tsf Cutoff Count Frequency CDF Exceedence Probability CFS % % % 0.002 32638 53. 226 53.226 46. 774 0.468E+OO 0.005 5323 8.681 61. 906 38.094 0.381E+OO 0.008 5270 8.594 70.501 29.499 0.295E+OO 0.010 4255 6.939 77.440 22.560 0.226E+OO 0.013 4222 6.885 84.325 15.675 0.157E+OO 0.016 2851 4.649 88.974 11. 026 O. llOE+OO 0.019 2250 3.669 92.644 7.356 0.736E-01 0.022 1661 2.709 95.352 4.648 0.465E-01 0. 025 899 1. 466 96.818 3.182 0.318E-01 0.028 866 1.412 98.231 1. 769 0.177E-01 0.031 694 1.132 99.362 0.638 0.638E-02 0.034 28 0.046 99.408 0.592 0.592E-02 0.036 16 0. 026 99.434 0.566 0.566E-02 0.039 17 0.028 99.462 0.538 0.538E-02 0.042 15 0.024 99.486 0.514 0.514E-02 0.045 7 o. 011 99.498 0.502 0.502E-02 0.048 14 0.023 99.521 0.479 0.479E-02 0.051 22 0.036 99.556 0.444 0.444E-02 0.054 28 0.046 99.602 0.398 0.398E-02 0.057 44 0.072 99.674 0.326 0.326E-02 0.060 19 0.031 99.705 0.295 0.295E-02 0.062 19 0.031 99.736 0.264 0.264E-02 0.065 12 0.020 99.755 0.245 0. 245E-02 0.068 21 0.034 99.790 0.210 0.210E-02 o. 071 17 0.028 99.817 0.183 0 .183E-02 0.074 11 0.018 99.835 0.165 0.165E-02 0. 077 12 0. 020 99.855 0.145 0.145E-02 0.080 13 0.021 99.876 0.124 0.124E-02 0.083 16 0.026 99.902 0.098 0.978E-03 0.086 10 0.016 99.918 0.082 0. 815E-03 0.088 10 0.016 99.935 0.065 0.652E-03 0.091 3 0.005 99.940 0.060 0.603E-03 0.094 4 0.007 99.946 0.054 0.538E-03 0.097 10 0.016 99.962 0.038 0.375E-03 0.100 11 0.018 99.980 0.020 0.196E-03 0.103 6 0.010 99.990 0.010 0.978E-04 Duration Comparison Anaylsis Base File: pre-dev.tsf New File: rdout.tsf Cutoff Units: Discharge in CFS -----Fraction of Time--------------Check of Tolerance------- Cutoff Base New %Change Probability 0.031 0.88E-02 0. 62E-02 -29.2 I 0.88E-02 0.040 0.61E-02 0.53E-02 -11. 6 I 0.61E-02 0.048 0.47E-02 0.48E-02 1. 4 I 0.47E-02 0.056 0.36E-02 0.33E-02 -6.4 I 0.36E-02 0.065 0.28E-02 0.25E-02 -10.5 I 0.28E-02 0.073 0.21E-02 0.17E-02 -19.4 I 0.21E-02 0.081 0.14E-02 0. llE-02 -24.4 I 0.14E-02 0.090 0.91E-03 0. 62E-03 -32.1 I 0.91E-03 0.098 0.55E-03 0.31E-03 -44.1 I 0.55E-03 0.106 0.29E-03 O.OOE+OO -100.0 I 0.29E-03 0.115 0.21E-03 O.OOE+OO -100.0 I 0.21E-03 0.123 0.16E-03 O.OOE+OO -100.0 I 0.16E-03 0.131 0. 82E-04 O.OOE+OO -100.0 I 0. 82E-04 Maximum positive excursion= 0.002 cfs ( 3.1%) occuring at 0.050 cfs on the Base Data:pre-dev.tsf and at 0.052 cfs on the New Data:rdout.tsf Maximum negative excursion= 0.034 cfs (-24.5%) occuring at 0.138 cfs on the Base Data:pre-dev.tsf and at 0.104 cfs on the New Data:rdout.tsf Base New %Change 0.031 0.029 -7.7 0.040 0.032 -18.3 0.048 0.049 1.5 0.056 0.056 -1. 5 0.065 0.061 -6.2 0.073 0.068 -6.8 0.081 0.077 -4.8 0.090 0.084 -6.1 0.098 0.094 -4.5 0.106 0.098 -7.5 0.115 0.100 -13.0 0.123 0.101 -17. 5 0.131 0.103 -21.2 WETPOND CALCULAT:IONS The following calculation is per Section 6.4.1 of the KCSWDM. Runoff Volume= Vr = (0.9Ai + 0.25Atg + O.lOAtf + O.OlAo) x (R/12) Ai=42400 sf Atg=53560 sf Atf=O Ao=O R=.47 Vr = [ (0.9) (42400)+(0.25) (53560)+0+0] X (.47/12) Wetpool Volume Vb= f(Vr) f=3 Vr=2019 cf Vb= 3x2019 = 6057 cf 2019 cf Wetpool volume= 13'xl20'x4.0' required. 6240 cf, thus satisfying the volume APPENDIX C POLLUTION PREVENTION AND SPILL PLAN Cramer Northwest, Inc. o Surveyors oPlanners oEngineers STORMWATER POLLUTION PREVENTION AND SPILL PLAN OF SINGH PLAT 19029 1201" AVE SE RENTON, WA 98058 FOR BOB SINGH P.O. BOX 98412 DES MOINES, WA 98148 November 10, 2009 C.N.I. JOB NO. 2006-186 Prepared by Larry S. Krueger, P.E. 945 N. Central, Suite #104 Kent WA 98032 (253) 852-4880 Fax (253) 852-4955 www.cramernw.com E-mail: cni@cramernw.com TABLE OF CONTENTS I. PROJECT OVERVIEW A. Existing Conditions B. Proposed Conditions II. POLLUTION GENERATING ACTIVITIES A. Storage and Handling of Liquids B. Storage and Stockpiling of Construction Materials and Wastes C. Fueling D. Maintenance, Repairs, and Storage of Vehicles and Equipment E. Concrete Saw Cutting, Slurry, and Washwater Disposal F. Handling of pH Elevated Water G. Application of Chemicals including Pesticides and Fertilizers H. Construction Related Erosion and Sediment Control Ill. BEST MANAGEMENT PRACTICES IV. INSPECTION FORMS AND WORKSHEETS V. SWPPS SITE PLAN SECTION~ !PROJECT OVERVIEW I. PROJECT OVERVIEW A. Existing Conditions: This project is located at 19029 120th Ave SE in Renton, Washington. The property is approximately 2.14 acres. The property has an existing home, garage, and concrete pathways, all of which will be removed. The existing house has a few bushes nearby, along with lots of grass, extending to the east property line. West of the existing buildings there is virtually no vegetation due to recent clearing and grading activity. The existing site drainage mainly sheet flows from the north to the south. There are approximately 3 acres of upstream area that flow to the site. There is a half street (SE 191 st Street ) located along the southern portion of this project that was built as part of the Jesse Glen subdivision. B. Proposed Conditions: We are proposing that the property be divided into nine residential lots, along with a drainage and recreation tract. This project will finish the half street installed by the Jesse Glen subdivision to the south. All of the lots except Lot 9 will gain access from JUD Tracts connected to SE 191 st Street. Lot 9 will access SE 191 st directly. Runoff from the new homes will be directed to perforated stubouts prior to being conveyed to a conveyance system that directs the runoff to a combined detention/wet vault in the southeast corner of the property. Driveway runoff will also be directed in a conveyance system to the same vault. Once the runoff has been treated and detained, it will be conveyed to the existing drainage system along the west side of 120th Ave SE. Upstream runoff will be collected near the northeast portion of the property and directed to the conveyance system of SE 191 st Street completely bypassing our onsite drainage system. New catch basins and pipe extensions will be provided as part of the completion of SE 191 st Street. They will convey runoff to the SE 191st street drainage system and the pond of Jessie Glen to the south. Construction activities will include demolition of some existing buildings and driveway, clearing and grubbing, grading and excavation, installation of a detention vault and utilities, building construction, paving and landscaping. This SWPPS plan contains a detailed description of how site conditions and construction activities will be managed during construction to minimize the possibility of off-site impacts to water quality. SECTION Ii ?OllllBT~ON GENERATING ACT!V~TIES II. POLLUTION GENERATING ACTIVITIES All pollutants, including waste materials and demolition debris, that occur onsite shall be handled and disposed of in a manner that does not cause contamination of stormwater. Good housekeeping and preventative measures will be taken to ensure that the site will be kept clean, well organized, and free of debris. Below is a list of specific polluting generating activities that are typically found on construction projects and how this SWPPS plan has addressed them for this project. A. Storage and Handling of Liquids: Some of the liquids that could possibly be stored on site are petroleum products, solvents, detergents, paint, pesticides, concrete admixtures, and form oils. Those liquids shall be stored in waterproof containers. The storage area shall be inspected regularly to detect any leaks or spills, and to identify maintenance needs to prevent leaks or spills. All storage containers shall include secondary storage. See BMP C-153 in Section Ill for information regarding storage and handling of liquids, spills, and secondary containment. B. Storage and Stockpiling of Construction Materials and Wastes: Construction materials that are stockpiled on site shall be covered during rainy times to prevent pollutants from entering the stormwater system. Portable Sanitation facilities shall be firmly secured, regularly maintained, and emptied when necessary. Solid wastes shall be stored in secure, clearly marked containers or removed from the site. See BMP C-150 in Section Ill for information regarding the storage and stockpiling of construction materials and wastes. C. Fueling: Equipment fueling may be necessary on site. On-site fueling tanks shall include secondary containment. Fueling shall not occur during evening hours. See BMP C-153 in Section Ill for information regarding spills and secondary containment. D. Maintenance, Repairs, and Storage of Vehicles and Equipment: Maintenance and repair of heavy equipment and vehicles that may result in discharge or spillage of pollutants to the ground or into stormwater runoff must be conducted using spill prevention measures, such as drip pans. Contaminated surfaces shall be cleaned immediately following any discharge or spill incident. Vehicle liquids shall be collected and stored in clearly marked containers. Vehicle liquids should be disposed at an approved hazardous waste disposal site. Emergency repairs may be performed onsite using temporary plastic beneath and, if raining, over the vehicle. All vehicle and equipment storage areas shall be inspected regularly to detect any leaks or spills, and to identify maintenance needs to prevent leaks or spills. See BMP C-153 in Section Ill for information regarding spills. E. Concrete Saw Cutting, Slurry, and Washwater Disposal: Process water, slurry, cuttings, and washwater resulting from concrete work shall be prevented from entering stormwater runoff by implementing BMP C-151 and BMP C-152 in Section Ill. These two BMPs provide information regarding the collection, treatment and disposal of the concrete work pollutants. F. Handling of pH Elevated Water: Construction sites with significant concrete work shall adjust the pH of stormwater if necessary to prevent violations of water quality standards. See BMP C-252 in Section Ill. BMP C-252 provides information regarding the treatment and disposal of water with elevated pH. G. Application of Chemicals including Pesticides and Fertilizers: Application of chemicals including pesticides and fertilizers shall be conducted in a manner and at application rates that will not result in loss of chemical to stormwater runoff. Manufacturers' recommendations for application rates and procedures shall be strictly followed. Chemicals shall be stored in waterproof containers. The storage area shall be inspected regularly to detect any leaks or spills, and to identify maintenance needs to prevent leaks or spills. All storage containers shall include secondary storage. See BMP C- 153 in Section Ill for information regarding storage and handling of liquids, spills, and secondary containment. H. Construction Related Erosion and Sediment Control: Site construction, clearing and grading may cause erosion and sediment control on site if the proper BMPs aren't implemented. The following ESC BMPs shall be used on this project: Clearing Limits: A plastic or metal fence shall be provided at the clearing limits of this project. Please see BMP D.3.1.1 in Section Ill. Cover Measures: Temporary and permanent seeding shall be provided on this project to minimize erosion of disturbed areas and to minimize the transport of sediment laden runoff to the nearby stormwater facilities. Please see BMP D.3.2.6 in Section Ill. Perimeter Protection: Silt fence shall be provided to prevent sediment laden runoff from leaving the site. Silt fence was chosen as the primary treatment BMP, although the size of the project requires a sediment trap. A sediment trap would require ditches to be constructed across sensitive areas so that the runoff could reach the trap. Silt fences inside the site in addition to those at the perimeter will help minimize the sediment laden runoff from leaving the site. Please see BMP D.3.3.1 in Section Ill. Traffic Area Stabilization: A stabilized construction entrance shall be provided at the entrances to the site. The construction entrances will reduce the amount of sediment transported onto paved road roads by motor vehicles or runoff. Please see BMP D.3.4.1 in Section Ill. SECTION ~II BEST MANAGEMENT PRAC1r~CES BMP C150: Material& On Hand Pu,po,e Quantities of erosion prevention and stdiment control materials can be kept on the project site at art times to be used for emergency situations such as unexpected heavy s1Jllllller rains. Having these materials on-site reduces the time needed to implement BMPs when inspections indicate that existing BMPs are not meeting 1he Construction SWPPP requirements. In addition, c:ontracton can save money by buying some materials in bulk and storing them at 1heir office or yard. Conditions of Use • Construction projects of any size or type can benefit from having Design and lnrtall'ftion 4-42 materials on hand A Sillllil commercial development project could have a roll of plastic and some gravel available for immediate protection of bare soil &1d temponuy berm construction. A large earlhworlc project, such as highway construction, might have several tons of straw, several rolls of plastic, flexible pipe, sandbags, geotextile fabric and steel 'T' posts. • Materials are stockpiled and readily available before any site clearing, grubbing, or earthwork begins. A large contractor or developer could keep a stockpile of maturials that are available to be used on several projects. • If storage space at the project site is at a premium, the contractor could maintain the materials at their office or yard. The office or yard must be less than an hour froin the project site. Depending on project type, size, complexity, and length, materials and quantities will vmy. A good minimum that will cover numerous situations includes: Material Measure Quantiht Clear Plastic 6 mil 100 foot roll 1-2 • 6 or 8 inch dianieter 25 foot section 4-6 Sandbam;_ filled each 25-50 Straw Bales for . . SO#each 10-20 lflUIJTif Snalk ton 2-4 Washed Gravel cubicvard 2-4 Geotextile Fabric 100 foot roll 1-2 Catch Basin Inserts each 2-4 Steel 'T' Posts each 12-24 • All materials with the uxception of the quarry spalls, steel 'T' posts, and gravel should be k1,pt covered and out of both S\Dl and rain. • Re-stock materials used as needed Volume II -Construction SIOlmwater Pollution Prevention Februery 2005 BMP C151: Concrete Handling Purpose Concrete work can generate process water and slurry that contain fine particles and high pH, both •>f which can violate water quality standards in lhe receiving water. This BMP is intended to minimize and eliminate concrete process water and '~IIITY from entering waters of the state. Conditions '!I Use Any time concrete is used, tliese 11lllllllgement practices shall be utili7.ed. Design and InvallaUofl Spedjkatlons Febnlary 2005 Concrete construction projei::ts include, but are not limited to, the following: • Curbs • Sidewalks • Roads o Bridges • Foundations 0 Floors o Runways • Concrete truck chutes, pumps, and intemals shall be washed out only into formed areas awaiting installation of concrete or asphalt • Unused concrete remaining in the trw:k and pump shall be returned to the originating batch plant for recycling. o Hand tools including, bill not limited to, screeds, shovels, rakes, floals, and trowels shall be wa;hed off only into formed areas awaiting iDstallation of concrete t>t asphalt • Equipment that Clllllot lt>e easily moved, such as concrete pavers, shall only be washed in arem: that do not directly drain to natural or constructed stonnwater conveyances. • Wasbdown from areas :;ucb as concrete aggregate driveways shall not drain directly to natwal or constructed stormwater conveyances. o When no formed areas are available, washwater and leftover product shall be contained in a !lined container. Contained concrete shall be disposed of in a JDllllllll:r that does not violate groundwater or surface water quality standards. Containers shall be checked for holes in the liner daily during concrete pours and repaired the same day. Volume II -construction S!Qmweter Pollutlon Prevention 4-43 BMP C152: Sawcutting and Surfacing Pollution Prevention P,upose Sawcutting and surfacing operations generate slllllY and process water 1hat contains fine particles and high pH (concrete cutting), both of which can violate the water quality standards in the receiving water. This BMP is intended to rnmimim and eliminate process water and slurry from entering waters of 1he State. Condltlons of Use Anytime sawcutting or surfil.cing operations take place, these management practices shall be utilized. SawcutliJ!g and surfacing operations include, but are not limited to, the following: Design and InstaJlaJJon SpedftcaJlons o Sawing o Coring 0 Grinding 0 Roughening o Hydr~emolition o Bridge and road sumcing o Slimy and cuttings shal!l be vacuumed during cutting and surfacing operations. • Slurry and cuni!J8!' sball not rmiain on permanent concrete or asphalt pavement overnight. o Slurry and cuttings shal L not dmin to any natural or constructed drainage conveyance. o Collected slurry and cu.tings shall be disposed of in a manner that does not violate groundwate1: or swfal:e water quality standards. • Process water that is generated dwing hydro-demolition, surface roughening or similar ~perations shall not drain to any natural or constructed drainage c.clllveyance and shall be disposed of in a manner that does not violate gr,>Wldwater or surface water quality standards. o Cleaning waste materid and demolition debris shall be handled and disposed of in a manner that does not cause cor,tamination of water. If the area is swept with 2L pick-up sweeper, the material mmt be hauled out of the area to an appropriate disposal site. Continually monitor operations to detennine whether slurry, cuttings, or process water could enter ,ivateJs of the state. If inspections show that a violation of water quality 1:tandards could occur, stop operations and immediately implemeot preventive measures such as berms, barriers, secondarY containment, all.d vacuum trucks. Volume II -Construction Slormwater Pollution PrwBlltlon February 2005 Bil/IP C153: Matarla!I Delivery, Storage and Containmem P,u,pme Prevent, reduce, or eliminate the discharge of pollutants from material deliveay and storaue to the stormwater system or watercourses by miuirnizin,~ lhe stonise ofhazardous mat.erials onsite, storing materials in ,i designated area, and installing secoruuuy con1ainment . Conditions of Use These procedures are sumible for use at all comtruction sites with delivery md storage of tllll! followllmg Jlllfderid11: Design and lnsta(ladm, Specijicalions February 2005 • Petrolemn produc:ls sudi as fuel, oil and grease • Soil stabiliz.els and bind1irs (e.g. Polyacrylamide) • Fertilizera, pesticides and herbicides • Deteigents • Asphalt and concrete compounds • Hazardous chemicals su,;:h as acids, lime, adhesives, paints, solvents and curing compotmds • Any other material that may be detrimental if released to the environment 'lbe following ll1leps should 112 takelm to mlnhnlw rials: • Tempormy storage area should be located away from vehicular traffic, near the construction en1rance(s ), and away from waterways or storm drains. • Material Safety Data Shm (MSDS) should be supplied for all materials stored. Chemit:als should be kept in 1heir original labeled containers. • Hazardous material stonsge on-site should be minimized • H81.8fdous materials shc,uld be handled as infrequently as possible. • During 1he wet weather season (Oct I -April 30), consider storing materials in a covered area. • Materials should be stored in secondazy coo1aimnerrts, such as earthen dike, horse trough, or even a children's wading pool for non-reactive materials such as detmg,:mts, oil, grease, and paints. Small amomts of material may be secxmdnrily contained in "bus boy" trays or concrete mixing trays. • Do not store chemicals, drums, or bagged materials directly on 1he gromd Place these iten:s oii a pallet and. when possible, in secoodacy containment Volume II -Construction Stonnwater Pollution Prevention 4-46 • If drums must be kept uncovered, store them at a slight angle to reduce ponding of rainwater on the lids to reduce corrosion. Domed plastic covers are inexpensive und snap to the top of drums, preventing water from collecting. Material Storage Areas Uld Secondary Con1aiorneot Practius: o Liquids, petroleum products, and substances listed in 40 CFR Parts 110, 117, or 302 shall b<, stored in approved containers and drums and shall not be overfilled. Containers and drums shall be stored in temponuy secondary containment facilities. • Temporary secondmy cmttaimnent facilities shall provide for a spill containment volume able to contain precipitation from a 25 year, 24 hour storm evmt, Pl!!! 10% of the total enclosed container volume of all containers, m; 110% ,)fthe rapacity of the largest container within iu boundary, whichever is grearer. • Secondmy C(Ulbgmnent facilities shall be impervious to the materials stored 1herein for a minimum contact time of 72 hours. • Secondmy conlai11111ent facilities shall be maintained free of accumulated rainwater 1111d spills. In the evmt of spills or leaks, accumulated rainwater 1111d spills shall be collected and pl~ into drums. These liquids sltlll be handled as hazardous waste unless testing determines 1hem to be non-bamdous. o Sufficient separation shmdd be provided between stored containers to allow for spill cleanup and emergency response access. o During the wet weather season (Oct 1 -April 30), each secondmy containment facility shall be covered during non-working days, prior to and during rain events. o Keep material storage 8J:ea5 clean, organized and equipped with an ample supply of approp1riate spill clean-up material (spill kit). o The spill kit should incl LJde, at a minimum· o I-Water Ril.1istant Nylon Bag 0 3-0il Abscrl>ent Socks 3"x 4' • 2-0il Abscrllent Socks 3"x 1 O' • 12-0il Ab!mbent Pads I 7"xl9" o I ·Pair Spilsh Resislant Goggles • 3-Pair Nrtrile Gloves o l 0-Disposnble Bags wi1h TI es o Instructions Volume II -Construct/on Slonnwater Pollullon Prevention February 2005 BMP C252: High pH Neutralizmtion nsing <:(h Description When pH levels in stormwater rise above 8.5 it is necessary to lower the pH levels to the acceptable range of 6.5 to 8.5, this process is called pH neu1ralization. pH neutralization involves the use of solid or compressed carboIJ1 dioxide gas in water requiring neutralization. Neutralized stormwater may bu discharged to surface waters under the General Construction NPDES permit but neuttalized process water must be managed to prevent discharge to surface waters. Proce.,s wastewater includes wastewaters such as concrete truck wasb-out, hydro-demolition, or saw-cutting shmy. Reason for pH neutralization A pH level range of 6.5 to 8.5 is typical for mc,st natural watercourses, and this neutral pH is required for the survival of aquatic orgm:~sms. Should the pH rise or drop out of this range, fish and other aquatic organisms m11y become stressed and may die. Calcium hardness can contribute to high pH v2lues and cause toxicity that is associated with high pH conditions. A high level of calci 1U11 hardness in waters of the state is not allowed. The water quality standard for pH in Washington State is in the range of 6.5 to 8.5. Groundwater standard for calcium and other dissolved solids in Washington State is less than 500 mg/I. Cames of high pH High pH at construction sites is most commonly caused by the contact of stormwater with poured or recycled concrete, cement, mortars, :md other Portland cement or lime- containing construction materials. (See BMP Cl51: Concrete Handling for more information on concrete handling procedures). The principal caustic agent in cement is calcium hydroxide (free lime). Advantages of C(h Sparglng • Rapidly neutralizes high pH water. ~ Cost effective and safer to handle than acid compounds. • COi is self-buffering. It is difficult to over,ilose and create harmfully low pH levels. • Material is readily available. The Chemical Process When carbon dioxide (CO:i) is added to water (H:z()), carbonic acid (H2COJ) is formed which can further dissociate into a proton {Ff) and a bicarbonate anion (HCOi) as shown below: · The free proton is a weak acid that can lower lhe pH. Water temperature has an effect on the reactic,n as well. The colder the water temperature is the slower the readion occurs 11nd the warmer the water temperature is the quicker the reaction occws. Most constructiot1. applications in Washington State have water temperatures in the S<J6F or higher Illll8' so the reaction is almost simultaneous. Treatment Procedures High pH water may be treated using continuo11S treatment, continuous discharge systems. These manufactured systems continuously mclllitor influent and effluent pH to ensure that pH values are within an acceptable range before being discharged. All systems must have fail safe automatic shut off' switches in the event that pH is not within the acceptable discharge l'llll8e. Only trained operatois may ,operate manufactured systems. System manufacturers often provide trained operators or training on their devices. The following procedure may be used when not using a continuous discharge system: • Prior to treatment, the appropriate jurisdiction should be notified in accordance with the regulations set by the jurisdiction. 0 Every effort should be made to isolate the potential high pH water in order to treat it separately from other stormwat« on-site. • Water should be stored in an acceptable s1orage facility, detention pond, or containJ111'1t cell prior to treatment. • Transfer water to be treated to 1he treaunent structure. Ensure that treatment structure size is sufficient to hold the ammmt of water that is to be treated. Do not fill tank completely, allow at least 2 feet offreebo:ird. 0 The operator samples the water for pH ani notes the clarity of the water. As a rule of thwnb, less COi is necessaiy for clearer '11rater. This informaticm should be recorded. • In the pH adjustment structure, add COz ~ntil the pH falls in the range of 6.9-7.1. Remember that pH water quality standards apply so aqjusting pH to within 0.2 pH units of receiving water (ba(:kground pH) is recommended. It is unlikely that pH can be adjusted 10 within 0.2 pH units using dry ice. Compressed carbon dioxide gas should be introduced to the water using a carbon dioxide diffuser located near the bottom of the tank, this will allow carbon dioxide to bubble up through the water and diffuse more evenly. • Slowly release the water to disd!arge mal:ing S1II1l water does not get stirred up in the process. Release about 80% of the water t'rom the structure leaving any sludge behind 0 Discharge treated water through a pond or drainage system • Excess sludge needs to be disposed of properly as concrete waste. If several batches of water are undergoing pH treatment, sludge can be left in treatment structure for the next batch treatment. Dispose of sludge when it fills 500/o of tank volume. Sites that must implement flow control for the developed site must also control stormwater release rates during construction. All treated stormwater must go through a flow control facilify before being released to slll'face waters which require flow control. Safety and Materials Handling • All equipment should be handled in accordance with OSHA rules and regulations. • Follow manufacturer guidelines for materials handling. Operator Records Each operator should provide: • a diagram of the monitoring and treatment equipment and • a description of the pumping rates and capacify the treatment equipment is capable of treating. Each operator should keep a written record of the following: • client name and phone number, • date of treal went, • weather conditions, • project name and location, • volume of water treated, • pH of untreated water, • amount ofCOz needed to adjust water to a pH range of 6.9-7.1, • pH of treated water and, • discharge point location and description. A copy of this record should be given to .1he client/contractor who should retain the record for three years. SECTION D.3 ESC MEASURES conveyed to a stabilized discharge point downstream of the distmbed areas. Surface water collection measures shall be installed concmrendy with or immediately following rough grading and shall be designed, constructed, and stabilized as needed to minimize erosion. "-- 7. Dewaterlng Control: The water resulting fiom construction site de-watering activities must be treated prior to discharge or disposed ofas s:pecified. 8. Dust Control: Preventative measures to mirrimize wind transport of soil shall be implemented when a traffic hazard may be created or when sediment transported by wind is likely to be deposited in water resources. 9. Flow Control: Swface water from disturbed areas must be routed through the project's onsite flow control facility or other provisions must mali.e to prevent increases in the existing site conditions 2- year and I 0-year runoff peaks disclwging fiom the project site during construction. D.3.1 CLEARING LJ[MJ['f§ D.3.1.1 1/24/2005 Prior to any site clearing or grading, those areas that arc to remain undisturbed during project construction shall be delineated. At a minimwn, clearing limits shall be installed at the edges of all critical area buffers and any other areas reqwred to be left uncleared such as portions of the site subject to clearing limits under KCC 16.82.150, areas around significant trees identified to be retained, and other areas identified to be left undisturbed to protect sensitive features. Purpose: The purpose of clearing limits is to pr.event distwbancc of those areas of the project site that are not designated for clearing or grading. This is illlportant because limiting site disturbance is the single most effective method for reducing erosion. Clearing limits may also be used to control construction traffic, thus reducing the disturbance of soil and limiting the amollllt of sediment tracked off site. When to Install: Clearing limits shall be install1d prior to the clearing and/or grading of the site. -' Measures to Use: Marking clearing limits by delineating the site with a continuous length of brightly colored survey tape is sometimes sufficient Thf, tape may be supported by vegetation or stakes, and it shall be 3 to 6 feet high and highly visible. Critical areas and their buffers require more substantial protection and shall be delineated with plastic or metal safety fences or stake and wire fences. Fencing may be required at the County's discretion to corilrol construction ttaffic or at any location where greater protection is warranted. Pemw,ent fencing may also be used if desired by the applicant. Silt fence, in combination with survey flagging, is also an acolplable method of marking critical areas and their buffers. Code: FE Symbol: Purpose Fencing is intended to (!) restrict clearing to approved limits; (2) prevent disturbance of critical areas. their buffers, and other areas required to be left undisturbed; (3) limit construction traffic to designated construction entrances or roads; and (4) protect i,rcas where marlcing with survey tape may not provide adequate protection. Conditions of Use To establish clearing limits, plastic or metal fence may be used: I. At the boundary of critical areas, their buffers, and other areas required to be left uncleared. 2. As necessary to control vehicle access to and on the site (see Sections D.3.4.1 and D.3.4.2). 2005 SurfiH:c Water Design Manual -Appendix D D.3. l CLEARING LIMITS Design and Installation Specifications 1. The fence shall be designed and installed according to the manufacturer's specifications. 2. The fence shall be at least 3 feet high and DIWil be highly visible. 3. The fence shall not be wired or stapled to trees. Maintenance Requirements l. If the fence has been damaged or visibility reduced, it shall be repaired or replaced immediately and visibility restored. · 2. Disturoance of a critical area, critical area buffor, native growth retention area, or any other area required to be left undistwbed shall be reported to the County for resolution. D.3.1.2 STAKE AND WIRE FENCE Code: SWF Symbol: Purpose Fencing is intended to (1) restrict clearing to approvi:d limits; (2) prevent distuibance of critical areas, their buffers, and other areas required to be left undfaturbed; (3) limit construction traffic to designated construction entrances or roads; and (4) protect any ureas where marking with survey tape may not provide adequate protection. Conditions of Use To establish clearing limits, stake or wire fence may be used: I. At the boundary of critical areas, their buffers, and other areas required to be left uncleared. 2. As necessary, to control vehicle access to and on the site (see Sections D.3.4. l and D.3.4.2). Design and Installation Specifications See Figure D.3.1 .A for details. Maintenance Requirements I. lfthe fence has been damaged or visibility reduet,d, it shall be repaired or replaced immediately and visibility restored. 2. Disturbance of a critical area, critical area buffi,r, native growth retention area. or other area required to be left undisturbed shall be reported to the County for resolution. 3. The County may require more substantial fencing if the fence does not prevent encroachment into those areas that are not to be disturbed. 2005 Surface Water Oesiw, Manual -Aooendix D • ;, D.3.2.6 D.3.2 COVER MEASURES TEMPORARY AND PERMANENT S.EE:Dl!NG Code: SE Symbol: -=oe:,.---1Gv,.__..,.,_ Purpose Seeding is intended to reduce erosion by stabilizing exposed soils. A well-established vegetative cover is one of the most effective methods of reducing erosion. .~·.I~ Conditions of Use I. Seeding shall be used throughout the project on dhturbed areas that have reached final grade or that wil I remain unworlced for more than 30 days. 2. Vegetation-lined channels shall be seeded. Channels that will be vegetated should be installed before major earthworlc and hydrosecdcd or coven:d with a Bonded Fiber Matrix (BFM). 3. Retention/detention ponds shall be seeded as required. 4. At the County's discretion, seeding without mulch during the dry season is allowed even though it will take more than seven days to develop an effective cover. Mulch is, however, recommended at all times because it protects seeds from heat, moisture loss, and transport due to runoff. 5. At the beginning of the wet season, all disturbed areas shall be reviewed to identify which ones can be seeded in preparation for the winter rains (sec Section D.5.2). Disturbed areas shall be seeded within one week of the beginning of the wet seaso1L A sketch map of those areas to be seeded and those areas to remain uncovered shall be submitted to the ODES inspector. The DOES inspector may require seeding of additional areas in order to prott:ct surrace waters, adjacent properties, or drainage facilities. 6. At final site stabilization, all disturbed areas not otlierwi~ vegetated or stabilized shall be seeded and mulched {see Section D.S.5). Design and Installation Specifications I. The best time to seed is April l through June 30, and September I through October 15. Areas may be seeded between July I and August 31, but irrigation may be required in order to grow adequate cover. Areas may also be seeded during the winter montlm, but it may take several months to develop a dense groundcover due to cold temperatures. The application and maintenance of mulch is critical for winter seeding. 2. To prevent seed from being washed away, confirm that all required surface water control measures have been installed. 3. The seedbed should be firm but not compacted because soils that are well compacted will not vegetate as quickly or thoroughly. Slopes steeper tllan 3H: IV shall be surface roughened. Roughening can be accomplished in a variety of ways, but the typical method is track walking, or driving a crawling tractor up and down the slope, 11:aving cleat imprints parallel to the slope contours. 4. In general, 10-20-20 N-P-K (nitlVgen-phosphonis-potassium) fertilizer may be used at a rate of90 pounds per acre. Slow-release fertilizers are preferred because they are more efficient and have fewer environmental impacts. It is recommended that areas being seeded for final landscaping conduct soil tests to determine the exact type and quantity of fertili2er needed. This will prevent the over- application of fc:rt:ilizcr. Distwbed areas within 20<1 feet of water bodies and wetlands must use slow- release low-phosphorus fertiliur (typical proportions 3-1-2 N-P-K). 5. The following requirements apply to mulching: a) Mulch is always required for seeding slopes groater than 3H:l V {see Section D.4.2. l ). 2005 Surface Water DcsiJ!ll Manual -Apocndix D 1124/2005 SECTION D.3 ESC MEASURES 1/24/20-05 b) lf seeding during the wet season, mulch is required. c) The use of mulch may be required during the dzy season at the County's discretion if grass growth is expected to be slow, the soils are highly erodible due to soil type or gradient, there is a water body close to the disturbed area, or significant precipitation (see Section D.5.2) is anticipated before the grass will provide effective cover. d) Mulch may be applied on top of the seed or simultaneously by hydroseeding. 6. Hydroseeding is allowed as long as tackifier is included. Hydroseeding with wood fiber mulch is adequate during the dzy season. During the wet season. the application rate shall be doubled because the mulch and tackifier used in hydroseeding break down fairly rapidly. It may be necessary in some applications to include straw with the wood fiber, but this can be detrimental to germination. 7. Areas to be pennanently landscaped shall use, soil amendments. Good quality topsoil shall be tilled into the top six inches to reduce the need for fertilizer and improve the overall soil quality. Most native soils will require the addition of four ioches of well-rotted compost to be tilled into the soil to provide a good quality topsoil. Compost use~ should meet Ecology publication 98-38 specifications for Grade A quality compost. · 8. The seed mixes listed below include recommended mixes for both temporary and permanent seeding. These mixes, with the exception of the wetla1d mix, shall be applied at a rate of 120 pounds per acre. This rate may be reduced if soil amendments or slow-release fertilizers are used. Local suppliers should be consulted for their recommendatio11S because the appropriate mix depends on a variety of factors, including exposure, soil type, slope, ;llld expected foot traffic. Alternative seed mixes approved by the County may be used. Table D.3.2.B presents the standard mix for !hos,, areas where just a temporary vegetative cover is required. fl' TABLE D.3.1:lJ~orliL'Y'EROS(ciN,Qt!'ITRot~p;tn l\fiX "'. .. :. ·.· ~.:-·~:t,-·. . •;:· ·'· ·:: .1.):.:,~· ·-~~-.:.,, ·_:,·-.... -. . %Weight % Purity % Germination Chewings or red rescue 40 98 90 Festuca rubre var. commutata or Festuca rubre Annual or perennial rye 40 98 90 Lolium multiflorum or Lolium perenne Redtop or colonial bentgrass 10 92 85 Agrostis alba or Agrostis tenuis White dutch clover 10 98 90 T rifolium repens 2005 Surface Wat.r.r Design Manual -Appendix D '·ii D.3.2 COVER MEASURES Table D.3.2.C provides just one recommended possioility for landscaping seed. -~-· / ... :.\t:r. -.. .. ·-,i :. t. TABLE D.3.2.C LANDSCAPING'SEEI)"MIX . .. :, . .-·-:-,;:: ,r.-~.-·: .. % lllleight % Purity % Germination Perennial rye blend 70 98 90 Loi/um perenne Chewings and red fescue blend 30 . -·. •.. 98 90 Festuca rubra var. commutata or Festuca rubra This turf seed mix in Table D.3.2.D is for dry situations where there is no need for much water. The advantage is that this mix requires very little maintenance . .. . . . . :;_::•,;- % VVelght % Purity % Germination Dwarf tall fescue (several varieties) 45 98 90 Festuca arundinacea var. Dwarf perennial rye (Barclay) 30 98 90 Loi/um perenne var. barclay Red fescue 20 98 90 Festuca rubra Colonial bentgrass 5 98 90 Agrastis tenuis Table D.3.2.E presents a mix recommended for bioswales and other intermittently wet areas. Sod shall generally not be used for bioswales because the seed mix is inappropriate for this application. Sod may be used for lining ditches to prevent erosion, but it will provide little water quality benefit during the wet season . . , .•. , Tall or meadow fescue Festuca arundinacea or Festuca elatior Seaside/Creeping bentgrass Agrastis palustris Redtop bentgrass Agroslis alba or Agrostis gigantea % Weight 1{1-15 5-10 • Modified Briargreen, Inc. Hydraseedlng Guide Wetlands Seed Mix %Purity % Germination 98 90 92 85 90 80 2005 Surface Water Design Manual -Appendix D 1/24/2005 SECTION DJ ESC MEASURES 1124noos The seed mix shown in Table D.3.2.F is a reconu:llellded low-growing, relatively non-invasive seed mix appropriate for very wet areas that are not regulated wetlands (if planting in wetland areas, see Section 6.3. I of the Su,face Water Design Manual). Otbc:r mixes may be appropriate, depending on the soil type and hydrology of the area. Apply this mixture at a rate of60 pounds per acre . . . .-.:· TABLE·D;J.l;F 'WE'f AREA SEED MIX* ·., ... . . ,• ~ ' %Weight % Purity % Germination Tall or meadow fescue 60-70 Festuca arundinacea or 98 90 Festuca elatior Seaside/Creeping bentgrass 10-15 98 85 Agrostis palustris Meadow foxtail 10-15 90 80 Alepocurus pratensis Alsike clover 1-6 98 90 T rifolium hybridum Redtop bentgrass 1-6 92 85 Agrostis alba • Modified Briargreen, Inc. Hydroseeding Gulde WeUands Seed Mb< The meadow seed mix in Table D.3.2.G is recommended for areas that will be maintained infrequently or not at all and where colonization by native plants is desirable. Likely applications include rural road and utility right-of-way. Seeding should take place in September or very early October in order to obtain adequate establishment prior to the winter months. The appropriateness of clover in the mix may need to be considered as this can be a fairly invasive species. If the soil is amended, the addition of clover may not be necessary. ..:~. ·.'TABLE D.3.l.C MEADOW SEED MIX . ;-.. ,,. % Weight % Purity % Germination Redtop or Oregon bentgrass 40 92 85 Agrostis alba or Agrostis oragonensis Redfescue 40 98 90 Festuca rubra White dutch clover 20 98 90 Trifolium repens . ~ .. Maintenance Standards for Temporary and Pennanent Seeding 1. Any seeded areas that fail to establish at least no percent cover within one month shall be reseeded. If reseeding is ineffective, an alternate method, such as sodding or nets/blankets, shall be used. If winter weather prevents adequate grass growth. this time limit may be relaxed at the discretion of the County when critical areas would otherwise be protect=<!. 2005 Surface Water Design Manual -Appendix D n..>, , f; 0.32 COVER MEASURES After adequate cover is achieved, any areas that eq,erieoce erosion shall be re-seeded and protected by mulch. If the erosion problem is drainage related, the problem shall be fixed and the eroded area re-seeded and protected by mulch. 3. Seeded areas shall be supplied with adequate moi:;ture, but not watered to the extent that it causes mnoff. D.3.2. 7 SODDING Code: SO Symbol: Purpose The purpose of sodding is to establish permanent turf for immediate erosion protection and to stabilize drainage ways where concentrated overland flow will occur. Conditions of Use Sodding may be used in the following areas: I. Disturbed areas that require short-term or long-tenn cover 2. Disturbed areas that require immediate vegetative ::over 3. All waterways that require.vegetative lining (except biofiltratioo swales-the seed mix used in most sod is not appropriate for biofiltration swales). Waterways may also be seeded rather than sodded, and protected with a net or blanket (see Section D.3.2.3). Design and Installation Specifications Sod shall be free of weeds, of uniform thickness (appn:rumately I-inch thick), and shall have a dense root mat for mechanical strength. The following steps are recommended for sod installation: l. Shape and smooth the surface to final grade in accordance with the approved grading plan. 2. Amend two inches (minimum) of well-rotted compost into the top six inches of the soil if the organic content of the soil is less than ten percent Compom used should meet Ecology publication 98-38 specifications for Grade A quality compost. 3. Fertilize according to the supplier's recommendations. Distwbed areas within 200 feet of water bodies and wetlands must use non-phosphorus fertilizer. 4. Work lime and fertilizer l to 2 inches into the soil, and smooth the surface. 5. Lay strips of sod beginning at the lowest area to be sodded and perpendicular to the direction of water flow. Wedge strips securely into place. Square the ends of each strip to provide for a close, tight fit. Stagger joints at least l2 inches. Staple on slopes steeper than 3H:IV. 6. Roll the sodded area and irrigate. 7. When sodding is carried out in alternating sttips or othCI'. patterns, seed the areas between the sod immediately after sodding. Maintenance Standards If the grass is unhealthy, the cause shall be determined md appropriate action taken to reestablish a healthy groundcover. If it is impossible to establish a hc:althy groundcover due to frequent saturation, instability, or some other cause, the sod shall be removed, the area seeded with an appropriate mix, and protected with a net or blanket. 2005 Surface Water Design Manual -Appendix D 112412005 S!iCfION D.3 ESC MEASURES D.3.3 PERJ!ME'Jl'EJR PROTECTION Perimeter protection. to filter sediment from sht.:twash shall be located downslope of all disturbed areas and shall be installed prior to upslope grading. Perimeter protection includes the use of vegetated strips as well as, constructed measures, such as silt fenc,,s, fiber rolls, sand/gravel barriers, brush or rock filters, triangular silt dikes and other methods. During the wet season, 50 linear feet of silt fence (and the necessary stakes) per acre of disturbed area mui:t be stockpiled on site. Purpose: The purpose of perimeter protection is to reduce the amount of sediment transponed beyond the disturbed areas of the construction site. Perimerer protection is primarily a backup means of sediment control. Most, if not all, sediment-laden water is to be treated in a sediment trap or pond. The only circumstances in which perimeter control is to be used as a primary means of sediment removal is when the catchment is very small (see below). When to Install: Perimeter protection is to be i11stalled prior to any upslope clearing and grading. Measures to Use: The above measures may be used interchangeably and are not the only perimeter protection measures available. If swface water is collected by an interceptor dike or swale and routed to a sediment pond or trap, there may be no need for the perimeter protection measures specified in this section. Criteria for Use as Primary Treatment: At the· boundary of a site, perimeter protection may be used as the sole form of treatment when the flowpath meets the criteria listed below. If these criteria are not met, perimeter protection shall only be used as a backup to a sediment trap or pond. Average Slope I.SH: IV or less 2H:1Vor less 4H:IV or less 6H:1Vor less IOH:IVor less Slope Percent 67% or less 50%or less 25% or less 16.7% or less 10%or less Flowpatb Length 100 feet 115 feet 150 feet 200 feet 250 feet D.3.3.l SILT FENCE !124/2005 Code: SF Symbol: Purpose Use of a silt fence reduces the transport of coarse uedinwnt from a construction site by providing a temporary physical barrier to sediment and reducing the runoff velocities of overland flow. Conditions of Use J. Silt fence may be used doWJ1Slope of all disturbed areas. 2. Silt fence is not intended to treat concentrated flows, nor is it intended to treat substantial amo.unts of overland flow. Any concentrated flows must tie conveyed through the drainage system to a sediment trap or pond. The only circumstance in which overland flow may be treated solely by a silt fence, rather than by a sediment trap or pond, is when the area draining to the fence is small (see "Criteria for Use as Primary Treatment" on page D-30). Design and Installation Specifications I. See Figure D.3.3.A and Figure D.3.3.B for details. 200S Surface Water Design Manual -Appendix D " D.3.3 PERJMETER PROTEcnON , The geotextile used must meet the standards listed below. A copy of the manufacturer's fabric specifications must be available on site. AOS (ASTM 04751) 30-100 sieve size (0.60--0.15 mm) for slit film 50-100 sieve size (0.30-0.15 mm) for other fabrics Water Pennittivity (ASTM 04491) 0.82 sec-1 minimum Grab Tensile Strength (ASTM 04632) 180 lbs. min. for extra strength fabric 100 lbs. mill. tor standard strength fabric Grab Tensile Elongation (ASTM 04632) 30% max. , ... , ~ Ultraviolet Resistance (ASTM 04355) 70% min. 3. Standard strength fabric requires wire backing to increase the strength of the fence. Wire backing or closer post spacing may be required for extra strength fabric if field performance warrants a Stronger fence. 4. Where the fence is installed, the slope shall be no steeper than 2H:IV. 5. !fa typical silt fence (per Figure D.3.3.A) is m.ed, the standard 4 x 4 trench may not be reduced as long as the bottom 8 inches of the silt fence is well buried and secured in a trench that stabilizes the fence and does not allow water to bypass or WJ,dennine the silt fence. Maintenance Standards I. Any damage shall be repaired immediately. 2. l f concentrated flows are evident uphill of the :ience, they must be intercepted and conveyed to a sediment trap or pond. 3. It is important to check the uphill side of the fence for signs of the fence clogging and acting as a barrier to flow and then causing channelization of flows parallel to the fence. If this occurs, replace the fence or remove the trapped sediment. 4. Sediment must be removed when the sediment is 6 inches high. 5. If the filter fabric (geotextile) has deteriorated due to ultraviolet breakdown, it shall be replaced. I FIGURE D.3.3.A SILT FENCE JOINTS IN fll.TER F"ABRIC SIW.!. 8E SPLICED AT POSTS. USE STAPLES, WIR£ RINGS. OR EQUIVALENT TO AlTACH FABRIC TO POSTS. 2·12• £fY 14 Ge. WIRE OR ;;::::;::==~ EQUIVALENT. IF STANDARD ---... -STREllGTH FABRlC · USED FILTER FABRIC--<>, -"1 r:, -------.;r r,.;:::..::· . / s· MAX. f ._ MINIMUM 4•x4" TRENCH ~ / \ BACKflLL 1RENCH Wm< NATM: SOIL OR 3/4"-1.5" POST SPACING MAY B. E: INCREASED WASHED GRAIIEL TO 8' IF 'MRE BACJQNG JS USED 2"x4" WOOO POSTS, STED. FENCE NOTE; F'ILTER F"8RfC FENCES SHALL BE INSTALLED ALONG CONl'OUR WHENMR POSS1B1.E POSTS. REBAR. OR EOUIVAL£NT . N II 2005 Surface Water Design Manual -Appendix D i/2412005 I l/24/2005 FIGURE D.3.3.B SILT FENCE INSTALLATION BY SLICING SILT FENCE-\ Fl.OW <>- I 00% COMPACTION EACH SIDE I • POST SPACING: 7' MAX. ON OPEN RUNS 4' MAX. ON POOLING AREAS. 2. POST DEPTH: AS MUCH BELOW GROUND AS FABRIC ABOVE GROUND. 3. PONDING HEIGHT MAX. 24" ATTACH FABRIC TO UPSTREAM SIDE OF POST. 4. DRIVE OVER EACH SIDE OF SILT FENCE 2 TO 4 TIMES WITH DEVICE EXERTING 60 P .S.I. OR GREATER. 5. NO MORE THAN 24" OF A 36" FABRIC IS ALLOWED ABOVE GROUND. 6. \~BRATORY PLOW IS NOT ACCEPTABLE BECAUSE Of HORIZONTAL COMP!1CTJON. -=,---OPERATION HORIZONTAL CHISEL POINT (76mm WIDTH) · ....•.....•.. · TOP OF FABRIC ::zzz:z:.::ztii~z;;::,.:z,z: BELT T TOP 8" DIAGONAl. ATTACHMENT DOUBLES STRENGTH AUACHMENT DETAILS: 1. GATHER FABRIC AT POSTS. IF NEEDED. 2. UTIUZE THREE TIES PER POST, ALL WITHIN TOP 8" OF FABRIC. 3. ?OSJTION EACH TIE DIAGONALLY. PUNCTURING HOLES VERTICALLY A MINIMUM OF 1" APART. 4. HANG EACH TIE ON A POST NIPPLE AND TIGHTEN SECURELY. \!SE CABLE TIES (50 ~) Of" SOf'T \VIRE. 1 ROLL OF SILT FENCE I I / 1 PLOW I l 200-300mm _J SILT [ENCE INSTALlAJ)ON BY SUCING METHOD I 2005 Surface Water Design Manual -Appendix D [).32 D.3.4 TRAF'FJC AREA STABILIZATION 'D.3.4.1 STABILIZED CONSTRUCTION ENTRANCE ~ Code: CE Symbol: I Purpose Construction entrances are stabilized to reduce. the amount of sediinent transported onto paved roads by motor vehicles or runoff by constructing a stabilized pad of quarry spalls at entrances to construction sites. Conditions of Use Construction entrances shall be stabilized wherever traffic will be leaving a construction site and traveling on paved roads or other paved areas within J,000 feet of the site. Design and lnstaliation Specifications 1. See Figure D.3.4.A for details. 2. A separation geotextile shall be placed under the :;palls to prevent fine sediment from pumping up into the rock pad. The geotextile shall meet the following standards: Grab Tensile Strengfh (ASTM 04751) 2Cl0 psi min. Grab Tensile Elongation (ASTM 04632) 30% max. Mullen Burst Strength (ASTM D3786-80a) 4()0 psi min. AOS (ASTM 04751) 20-45 (U.S. standard sieve size) 3. Hog fuel (wood based mulch) may be substituted for or combined with quarry spalls in areas that will not be used for permanent roads. Toe effectivene;s of hog fuel is highly variable, but it has been used successfully on many sites. It generally requires more maintenance than quarry spalls. Hog fuel is not recommended for entrance stabilization in urban areas. The inspector may at any time require the use of quarry spalls if the hog fuel is not preventir,g sediment from being tracked onto pavement or if the hog fuel is being carried onto pavemenL Hog fuel is prohibited in permanent roadbeds because organics in the subgrade soils cause difficulties with compaction. 4. Fencing (see Section D.3.1) shall be installed as necessary to restrict traffic to the construction entrance. 5. Whenever possible, the entrance shall be constructed on a firm, compacted subgrade. This can substantially increase the effectiveness of the pad and reduce the need for maintenance. Maintenance Standards I. Quany spalls (or hog fuel) shall be added if the pad is no longer in accordance with the specifications. 2. If the entrance is not preventing sediment from beiing tracked onto pavement, then alternative measures to keep the streets free of sediment shall be used. This may include street sweeping, an increase in the dimensions of the entrance, or the iCIStallation ofa wheel wash. If washing is used. it shall be done on an area covered with crushed rock, and wash water shall drain to a sediment trap or pond. 3. Any sediment that is tracked onto pavement shall be removed immediately by sweeping. The sediment collected by sweeping shall be removed or stabilized on site. The pavement shall not be cleaned by washing down the street, except when 1:weeping is ineffective and there is a threat to 2005 Surface Water Design Manual-Appendix D 1/24/2005 I .:>C"-, J JUN lJ . .) public safety. If it is necessary to wash the streets, a small sump must be constructed. The sediment would then be washed into the sump where it can be controlled and discharged appropriately. if 4. Any quarry spalls that are loosened from the pad and end up on the roadway shall be removed immediately. 5. lf vehicles are entering or exiting the site at points other than the construction entrance(s). fencing (see Section D.3.1) shall be installed to control ttaffic. FIGURE D.3.4.A STABILIZED CONSTRUCTION ENTRANCE INSTALL DRIVEWAY CULVERT IF TIIERE IS A ROADSIDE DITCH PRESENT, AS PER KING COUNTY ROAD STANDARDS 4 "-s• QUARRY SPALLS --~ GEOTEXTILE--_,, AS PER KING COUNTY ROAD STANDARDS, DRIVEWAYS SHALL BE PAVED TO THE EDGE OF R-D-W PRIOR TO INSTALLATION OF THE CONSTRUCTJOII ENTRANCE TO AVOID DAMAGING OF THE ROADWAY IT IS RECOMl,IENDEO THAT THE ENTRANCE BE CROWNED SO THAT RUNOFF DRAINS OFF THE PAD I 1/24/2005 200S Surface Water Design Manual -Appendix D SECTl<)N IV ~NSPECTION FORMS .AND WORKSHEETS Constructiout Site Pollution P1revention & Spm Inspection Sheet Projac:t: Daife: 11'1Sp3Cted by: rnne: l/lfeaflher: . Duration since fail rainfall? Cwrently 24 hows 2-3 days > 5 days Blb'IP Observations, Cclm11e11ds, Coarective Aclions Storage.& Handrmg fit liquids cm Nc,t.(m Storage and St=kpfflug of Construction M&lmrials and waste cm: l\lmOK Fuating C>K NotOK Maintenance, Repairs and Storage of Vehicles IA Equipment cm: Noto« Concrete Saw Cutting, Slurry, & WashwaterDisposal (K( Neto« Handfmg of pH Bevaled Water CIK l\lctOK Application o'I Chemlc:ails including F'e&ticldes and Fertifeers CIK NotOK Construction Related Erosion and Sadiment Control: CIK !\lot OK I certify that this repon is true. and com_ to the bes:! of my knowledge and belief lnspeclor Initials: SECTION ~V ~NS1?1EC1f'ION FORMS AND WORKSHEETS Construction Site Pollution Prevention & Spill Inspection Sheet Project: Date: Inspected by: Time: Weather: Duration since last rainfall? Currently 24 hours 2-3 days > 5 days BMP Observations, Comments, Corrective Actions Storage & Handling of Liquids OK Not OK Storage and Stockpiling of Construction Materials and Waste OK Not OK Fueling OK Not OK Maintenance, Repairs and Storage of Vehicles & Equipment OK Not OK Concrete Saw Cutting, Slurry, & Washwater Disposal OK Not OK Handling of pH Elevated Water OK Not OK Application of Chemicals including Pesticides and Fertilizers OK Not OK Construction Related Erosion and Sediment Control: OK Not OK I certify that this report is true, and complete to the best of my knowledge and belief Inspector Initials: Construction Site Pollution Prevention & Spill Inspection Sheet Project: Date: Inspected by: Time: Weather. Duration since Ill!~ rainfall? Currently 24 hours 2-3 days > 5 days BPJIP ObseMltions, Commems, Corrective Actions Storage & Handling of Uquids CtK NotOK Storage and Stockpiling of Construction IVlater1als and Wast.e OK NotOK Fueling OK NotOK Maintenance, Repairs and Storage of Vehicles & Equipment 01< NotOK Concrete Saw Cuffing, Slurry, & Washwater Disposal OtC NotOK Handling of pH Elevated Water OK NotOK Application of Chemicals including Pesticides and Fertilizers Olt Not OK Construction Related Erosion and Sediment Control: OK NotOK J certify that this report is true, and complete to the best of my knowledge and belief Inspector Initials: ( ( ( :&,ti~l~?~t~~~)~l:i•;:~B;1;;:''' List all spllls and leaks of toxic or hazardous pollutants that were significant but are a limited to, release of sill or hazardous substanges la excess of reportable quantities, Although not required, we suggset you 11st spllls and leaks of non.f'lazardous materials. Date (month/day/yea r) Location (as Indicated on 111te map) Type of Material Description Quantity I Source . " Known ZOOS Surface Water Design Manual (CSWPP Forms) R81180nfor Splll/Leak Response Procedure Amount of Material Recovered MaterlalNo longer 8xpo88dto Stormwater (Yea/No) Page 1 Preventive Measure Taken ( ( ',. ( ·r<~iGf~. Ust all spllls and leaks of toxic or hazardous pollutants that were significant but are D9i llmlted to, release of 2!I or l}pmrdous substances ID exc,u of repprtabie quantities. Although not required, we suggest you Hat spills and leaks of non-hazardous materlals. Data (month/day/yea r) Location (aa Indicated on site map) Type of Matarlal Description Quantity Source , If Known 2005 Surface Water Design Manual (CSWPP Forms) Reason for Splll/Leak Response Procedure Amount of Matertal Recovered Materlal No longer expoaedto Stormwater (Yea/No) Page 1 Preventive Measure Taken SECTION VI ~WPPS snne PlAN