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............................... .................. .................................................. ...............-......... .................... .................. ............................... TIG TE1. ..................::: ::: : :::: .::::.:::: ::: . ... T <'..' . A 111 . >::::>:::>::: >: ...: . Y. E :: cU .: Olt »::::;. IAs l! [ OUR JOB NO. 5734 GRve9 SEPTEMBER 1996 Of w Z ON AU Prepared By: ExPiRES C 1 1144ti BARGHAUSEN CONSULTING ENGINEERS, INC. 18215 72ND AVENUE SOUTH CITYY OFRENTON KENT, WASHINGTON 98032 RECEOVED (206) 251 -6222 FEB 19 1997 BUILDING DIVISION mP�G o i CIVIL ENGINEERING, LAND PLANNING, SURVEYING, ENVIRONMENTAL SERVICES 9. "N.E!G�� TABLE OF CONTENTS I. INTRODUCTION/GENERAL INFORMATION A. Introduction/General Information 1. TIR Worksheet 2. Site Location II. PRELIMINARY CONDITION SUMMARY III. OFF-SITE ANALYSIS A. Upstream Drainage Analysis B. Downstream Drainage Analysis IV. RETENTION/DETENTION ANALYSIS AND DESIGN A. Existing Site Hydrology B. Developed Site Hydrology C. Hydraulic Analysis D. Retention/Detention System V. CONVEYANCE SYSTEM DESIGN AND ANALYSIS VI. SPECIAL REPORT AND STUDY VII. BASIN AND COMMUNITY PLAN AREAS VIII. OTHER PERMITS IX. EROSION/SEDIlVIENTATION CONTROL DESIGN X. ADDITIONAL DOCUMENTS A. Bond Quantity Worksheet B. Retention/Detention Facility Summary Sheet and Sketch C. Declaration of Covenant XI. MAINTENANCE AND OPERATION MANUAL 1.0 PROJECT OVERVIEW The proposed project is located within the northeast quarter of Section 18, Township 23 North, Range 5 East of the Willamette Meridian in King County. More specifically, it is located on the northeast corner of the intersection of South Grady Way and Talbot Road South. The site is irregular in shape and is 1.51 acres in size. Grady Way provides approximately 460 feet of frontage along the south side of the property, Talbot Road South provides approximately 270 feet of frontage to the west, and South 7th Street provides 140 feet of frontage to the north. The adjacent property to the north also provides approximately 280 feet of frontage along the property. The property is an abandoned railroad line with no existing tracks on site. A portion of the property is vacated right-of-way for South 7th Street. Main overhead power lines run across the site, with some poles located in the center of the property. The relocation of these lines will be coordinated with Puget Power. The proposed project includes construction of a new Chevron Mini-Market facility with a convenience retail market, car wash, mini-lube, and gasoline sales. This facility will include one 2,300 square foot mini-market building, one 38-foot by 52-foot gasoline pump island canopy with eight dispensers, one 1,450 square foot mini-lube, one 2,000 square foot drive-through car wash, vacuum island, stormwater detention pond, new landscaping, paving, lot lights, and signage. Additionally, the proposed project will include the installation of two new 12,000-gallon and one 15,000-gallon fiberglass underground gasoline storage tanks and product piping. This underground system is double-containment type with associated leak detection devices. All systems meet or exceed 1988 USC, NAPA, and state and local regulations. The project also includes construction of sidewalks along the property frontages with South Grady Way and Talbot Road South where they do not already exist. 2.0 PRELIMINARY CONDITIONS SUMMARY Not applicable. 3.1 UPSTREAM DRAINAGE ANALYSIS This site is essentially isolated from off-site runoff. The site is basically surrounded by roadways that do not drain onto the site with the exception of the northeast corner of the project. This corner is connected to an existing parking area and building that utilize their own storm drainage system as well as the existing drainage system that runs through the property. 3.2 Downstream Drainage Analysis The project proposes the construction of an on-site detention system which ultimately discharges into the existing public storm drainage system located on the property. This system flows westerly into South 7th Street and continues through the City's mainline for a minimum of one mile downstream (see attached City of Renton Manhole and Pipe Inventory Map). 5734.005 [TN/ps] 4.0 RETENTION/DETENTION ANALYSIS Storm drainage detention calculations for the project were based on current requirements for the City of Renton using the SCS based methods established by the 1990 King County Storm Drainage Manual. The detention criteria established by the City of Renton is to release the existing 2-year, 10-year and 100-year/24-hour storms while detaining their respective post-developed storms. The required detention volume will be achieved with an open pond design, as well as utilizing the on-site conveyance system for some of the storage volume. Current on-site conditions of the property consist mostly of a mixture of low to high grassy areas with some trees. Also located on the site are some existing concrete pads and areas of gravel surfacing that were ignored when computating the existing conditions hydrographs. The current Soils Conservation Maps have identified this region as urban development. A Type "D" soil is assumed on the site based on the geotechnical report and respective valley location. A conservative predeveloped curve number of 86 was selected rather than the 89 that is shown for meadow and pasture to ensure that existing conditions are more closely met before the railroadline was established. This will provide a bit of a safety factor in the sizing of the detention facility. 5734.005 [TN/ps] I. PROJECT OVERVIEW _ . . —Z--- COPYRIGHT 199`f TltenwiFiev,Map SEE (���:> MAP — ,.rw AV le Su I-------------- - _ PONECL V--Su-_,,r,i - 1p ,-r`^(E d \ 1HFMA5 SW S SLY �"�i .S RA AV SW R5E = Are :. ,�..; y S NEG AY SW }Y k' � SAV E SN Z crr I u n w r AT ~-- - AV SW §� L NO V "° VE. ..:,.. ADD GI f )00 1900 4 i1 AV _sv. iSiEYEN$�/��+'NV r LL._... ie LE L ND ....-_AV '� 21 $ MArll AV 1 -I N A E VA LEY R S dwamlL AY SI o N �311dn s b�IN1 L„ In N z nv a3tY11 �1�v1 ! ..5�. DDr�t 6l A� N N L.J Uk( •Y lik AY 1n ��-_ 'd /' I •.�a nV 3 i Re SHA UCK 14 Ay rn Arz -.ice z T i� 5 ^� stnYo i ;`g a ,� s o - t, 1500 T i '�xDRRfS N �AV _ ;r Oa , r.• »�HORRrs Av $ ,.z R5 O zoo I J T S�.$Jam '^ wr os rkBOt ,� H ? �� - 3 Svt ERS• Av s S LOGAN AV IN ..r�n:' rra�'l�'♦ � � 1TM(ks Av 2F •PO -�i� f1n�, -ix( +•Y.. � � �BU ETT '�J" N Ay V1 $$�.t l�_.. � .A CQ•"U` -�• . �r ,^' �s 4 ^'r A rk ���� y PE�� S yi'a� •"1�IL17 yy S AV e F /r S i � ..;: �S I LI AY F;I Y•^ ' WELES -'A -•p€ s t��"!� mnG!.R- AYE- AV x F y A x z S y MAI soD H - S . WELLS AV -� ' F ,1�r ♦4 Ln� 1 NOSN39 #= , S I-yELLS H-.). J a v .- AV x AY xll x lL AY 3 = MLEY 2 - `•ry S CEOA0.AV O b �G^ CEDAR �' ' AY i $� Ar S 100 H `s r o n ' PARK =" �L0°— v sE 047 >.� ��Ocr -----71 � W—A�-7-- — .0 e _ .31- AV L--- —--N"•��� IDSTH AY' 8 - �—._ 5E I N_ 5 y ``'+ $ GRANT AV 0 J00''• '• Ri 8 GARDE 1 .- 8 AV-�i , AV 6600 o-Y GRANT HIGH 001 ..HiGH AV S /: fR = HGDW AY x AOO�N-.i+._. E}o I v 1 roo I rActo AV#• SE A -- 9$ N y�AS yl e µosr 19TH PAY SE ,�.W 'N \ - g$ 11i 1x I.. Z 8 llx[DLx A L•OMF�EVp x� .. .�- . ,\ i 11 TH z�v SE.'`II - H .�• - I ` - _14A00I-' `u I� , 1 wrp P f 9 T ,•,�: A'r' ..._�_ H A 1F °u,r / IAt CT SE �F A�,SL IISTH AY$(. ht[ 4a 'T t44r 9N p��r1 4 I:ATNAY^ "i_ N w n o a r P y ,a YI$ 1151H AY S( 81n I kE 1161Hi I� AV �� �SE §� z 11 H ��♦ +ryii..'. - Ytl p v 'suao A u AV E N^ EDMONDS AV e!i : ^ a+,/1 � p.�� __a,Jai j r♦`4 ,",t4�3 .�fi� a _`t� ♦�5, �ILC'+. "1r18 x 119TH AV St �El � '1 .k`✓SvP," I \ -i'` k' - •7'dTii6�: h��Q {\h, it '�sy'� psyz.,"'�v-_"_-_- �e A .,., ,, 1 r01 4�Ivrl r7�Yy!y 1201H AV�SE'Y`�Y%� f k - 'S♦ '^.. aa ,g O .. wkl.usw Rt .112N0 AV SC� r:.ti 11 h• ._ .A u .�+ � �� R� .,, '� , _ z I27N0 Av SE vnn:7Ru. _'lr' Of st p\� 11 r ``,.` - -'..i f-'.4�0 'I« _....��s>ti I Y/3 9 'Oe,.l 'At nun 'Y'S7e r••' -� f Page 1 of 2 King County Building and Land Development Division TECHNICAL INFORMATION REPORT (TIR) WORKSHEET PROJECTPART 1 • I PROJECTPART 2 • • I DESCRIPTION PROJECT Project Owner M . G K S a n fi0. Project Name Address 4 S o9 / Cr �'� mac, S>� Location 1VE Coy. o'FZ NO7� GrA��W Phone 2 a G �4, 1 _ ¢Z,4.2 Township i k4 I G�K 610 Range °� 5 Project Engineer Section g Company 6gr ' ne�-r Project Size AC Address Phone 8Z 15 l ZhAve, Upstream Drainage Basin Size AC ZoL 251- G22Z • • PART4 • ERMITS Q Subdivision Q DOF/G HPA Q Shoreline Management Q Short Subdivision Q COE 404 Q Rockery Q Grading Q DOE Dam Safety Structural Vaults �[ Commercial Q FEMA Floodplain Q Other Q Other Q COE Wetlands F-D HPA COMMUNITYPART 5 SITE I DRAINAGE I Community Drainage Basin G� � 9� cr PART 6 SITE CHARACTERISTICS Q River Q Floodplain Q Stream Q Wetlands Q Critical Stream Reach Q Seeps/Springs Q Depressions/Swales High Groundwater Table Q Lake Q Groundwater Recharge j 0 Steep Slopes Other Q Lakeside/Erosion Hazard SOILSPART 7 Soil ape Slopes Erosion Potential Erosive Velocities i, D.5 I — Z/ I�o n.t /Vo •�- Q Additional Sheets Attatched 1/90 Page 2 of 2 King County Building and Land Development Division TECHNICAL INFORMATION REPORT (TIR) WORKSHEET DEVELOPMENTPART 8 REFERENCE LIMITATION/SITE CONSTRAINT 0 Ch.4-Downstream Analysis C { oi� 4-It° 0 ; s -74-ti s fi a -_ - 0 a - a _ 0 Additional Sheets Attatched . . - MINIMUM ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION FOLLOWING CONSTRUCTION Sedimentation Facilities Stabilize Exposed Surface Stabilized Construction Entrance 0 Remove and Restore Temporary ESC Facilities Perimeter Runoff Control Clean and Remove All Siit and Debris Clearing and Grading Restrictions Ensure Operation of Permanent Facilities 0 Cover Practices 0 Flag Limits of NGPES Construction Sequence 0 Other Other i fft l Grass Lined Channel 0 Tank 0 Infiltration Method 5E3�f Analysis Pipe System 0 Vault � Depression H 0 Open Channel 0 Energy Dissapator E::] Flow Dispersal Compensation/Mitigation Dry Pond 0 Wetland 0 Waiver of Eliminate Site Storage Wet Pond 0 Stream 0 Regional Detention —/W� Brief Description of System Operation OPe" pond S ' 2 e� �� Z Y /O - / J y� Facility Related Site Limitations Additional Sheets Attatched Reference Facility Limitation PART 11 STRUCTURAL ANALYSIS PART 12 EASEMENTSfTRACTS requirespecial 0 Drainage Easement Cast in Place Vault 0 Other 0 Access Easement 0 Retaining Wall Native Growth Protection Easement X Rockery>4'High 0 Tract 0 Structural on Steep Slope 0 Other PART 14 SIGNATURE OF • • • I or a civil engineer under my supervision have visited the site. Actual site conditions as observed were incorporated into this worksheet and the attatchments. To the best of my knowledge the information provided here is accurate. Sig"'d'DW. 1/90 H. PREL-RvIINARY CONDITION SUMMARY III. OFF SITE ANALYSIS f µ•- -s la[he \aL6-It 4E « lo i I �� F-7d -FA Ed faChU atL-7 alb al:s a tv ha �_ Ivhu / Iart-tr tv6-4 W6-6 IUM lac6 n 16r7_7 16I7-6 , IaN7-t, _,. ULL-a w7-I , 100-10 ax7-1. SUNSET -f / \ 1 -a aN7-l3 M.C7-3 un a > - Iar7-,/ > > 4,C7 lan-7 -1, - fat7 ar7-n ar7-5"m la7(7-t < ,v7r ,477-10 tal7� IaC'7i all- 6X7_3 , _U ta47-[ Ia/A-1 ,ale-, 1"7 Iaf7- , -1. 14"-9 aM-a aM [e IaM-, 14n an-t AC7 1a27-a W7_ 1at77-3 MR11-1 aM-a la.h la/e- �-6 -17 alarm a.Ce-9 I6C7-I an-a LIfT [7ATIOt a»t fazes ICX" aa-[ are-u IaJe- ij AID"laxj-t 1 Ilk IaD6-. we-le - ! 1L 1 %xv-a faze-I, IarFts — .. . _ IGX" lane-a _ ,anr le 141e-7 —� s GTH IT 4>" °e-11 tar6-17 fac.t Ivhu a[e-7 %A ta[H 100-a ,Kl 1 lae.-3 iaD,-. Ian6-[ ta[►-t. lazh ,are-ta a 461 014z.-lA IaE6-1] fa7e--1 arr-It y _ 7 ST , 7TH - - Iate 1- I6,1:►-i taL6-16 Iv s tT i ME to -- eLc" ELM" ["II-6 tam 40 a.7}a z1,Se 1!1,6a-a may{ 7 �ti1/7-0 1!Llil-7 / � et►o-, r -u etc" etas u — ru" a.a-te [L�a-u ant etr ala-a eta" [u'e� ( [Ln-a etc"_ , 1 aa-f n la fi MG:149 ELC,4-1 an-s ar.-tt at«-17 _ [UH [IF•64 arHa � [161-4 W"-16 M4-a CL1h7 aAW [1.6.-a / [Lo-u �y tt,ea-ta [LCa-i / nr \ a� } \ {- \ `- ar f4U—� etlf"I [L t! �\ -.-tU6a4j[W4� \[WhT7 �-4 [UAa-M �a.Ch7 Il ru4" [U.-7 � HI ar4-7 el." eLes-G � ' / [6z6-! ELG "t ar." 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Yr.. ...,..rn..v....{:.:{•:::}5::v., , tl..�VD V .............:.!.r.e.....n,..;.;..;;. :.:..:::::::.:.:::::::•::.•:::::.:�.:{::.::::::•::::::r::•::�:{.;f.,.:..:::::: {s..).?{.n•::.::}.x,! ::•.�:.:::::..l:n.::::n..:r.,....l...,..se�lttter��tl�tt:irk�tb!i oth c. r fi i�. .......:..... .::4i<:>::::>::>$:;. L1Table Coc 112/92 IV. RETENTION/DETENTION ANALYSIS AND DESIGN U. S. DEPARTMENT OF AGRICULTURE SOIL CONSERVATION SERVICE KING COUNTY AREA. WP SOIL LEGEND The first copitol letter is the initial one of the soil no me. A second co�ocl letter, A. B,C. O, E, or F ind.cotes the Gloss of slope. Symbols withow a sloce lent, ore those of nearly level soils. SYMBOL NAME AgB Alderwood gravelly sandy loom,0 to 6 percent slopes AgC Aldetwood gravelly sandy loom,6 to 15 percent slopes , AgO Aidenvood gravelly sandy loom, 15 to 30 percent slopes !. AkF Aiderwood and Kitsop soils,very steep - • ArrB Arenas,Aldenvood molerial,0 to 6 percent slopes• I-c A„{ Arcnts,Alderwood material,6 to 15 percent slopes 0 An A,—Is, Everett material B<C -Beousite gravelly sandy loom,6 to 15 percent slopes Be0 Beovsite gravelly sandy loom, 15 to 30 percent slopes ELF Be-twice y.os-ei!;zcn4�Ica.,43:a 75;:—:::_io,.ac. 1.•'. IBh Bellingham silt loom car Brlscot silt loom B. Buckley silt loom Cb Coastal Benches 4i'• Eo Earlmont silt loam Ed Edgewick fine sandy loam !....,,, EvB Everett gravelly sandy loom,0 to 5 percent slopes EvC Everett gravelly sandy loom,5 to 15 percent slopes •'••' Ev0 Everett gravelly sandy loom, 15 to 30 percent slopes. Sac c.. EwC Everett-Aldenvood gravelly Bondy looms,6 to 15 percent slopes InA Indianola loomy fine sand,0 to 4 percent slopes Inc Indionoto loomy fine sand,4 to 15 percent slopes- - !•'••••^•f 1.0 Indianola toomy fine Bond, 15 to 30 percent slopes KpB Kitsop silt loam,2 to 8 percent slopes - fi...d„- KPC Kitsop silt loom,8 to 15 percent slopes 1 Kp0 Kitsop silt loom, 15 to 30 percent slopes - Se tr..l• KsC Klaus gravelly loony sand,6 to 15 percent slopes li...Id.. Ma Mixed aliwiol fond i•....,.•t N<C Nei It ore very grove l ly loamy sand,2 to 15 percent slopes Ng Newberg silt loam - Nk Nooksock silt loom "•-tl• No Norma sandy loomOr 0rcos peat Os Ovidia silt loom ovc Ovoil gravelly loom,0 to 15 percent slopes OvO OvoII grove Ily loom, 15 to 25 percent slopes OvF OvoII gravelly loom,401a 75.percent slopes Pc Pitchuck loony,fine Bond Pk Pilchuck fine sandy.loom (k+ P. Puget silty clay loom - Py Puyallup fine sandy loom ' RoC Rognor fine sandy loam,6 to 15 percent slopes Roo Rognac fine sandy loom, 15 to 25 percent slopes RdC Rognar-Indionola association,sloping e RdE Rognor-indiano1a association,moderately steep• Re Renton silt loam 'Rh Riverwosh So Solal silt locm - Sh - Soomomish sill loam SI. Sean le mock Sm Shako,wa.c k Sn Si silt loom So Snohomish silt loom S, Snohomish s.11 loam, thick swfoce variant Sa Sultan s.lt loam Tv Takw.lo n••s<o ll, U't— one !vo Wood•nv.11e 1.1, loom � l ly compas.t.tn OI.•4)r♦ s•]n.,ve vw:ohlr ct.o„,ho,,•1 ,tv-.., •- .n,ha arCa,is``•' .• I.ct . ..v,,.allec w,•Il. —gh t, .ntr,nv rc tv e./rc,rd use of KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TABLE 3.5.2B SCS WESTERN WASHINGTON RUNOFF CURVE NUMBERS SCS WESTERN WASHINGTON RUNOFF CURVE NUMBERS (Published by SCS in 1982) Runoff curve numbers for selected agricultural, suburban and urban land use for Type to rainfall distribution, 24-hour storm duration. CURVE NUMBERS BY- HYDROLOGIC SOIL GROUP LAND USE DESCRIPTION A 8 C D Cultivated land(1): winter condition 86 91 94 95 Mountain open areas: low growing brush and grasslands 74 82 `1 89 92 Meadow or pasture: 65 78 85 89 Wood or forest land: undisturbed 42 64 76 Wood or forest land: young second growth or brush 55 72 81 86 Orchard: with cover crop 81 88 92 Open spaces. lawns, parks, golf courses, cemeteries, landscaping. good condition: grass cover on 75% or more of the area 68 80 86• 90 fair condition: grass cover on 50% to 75%of the area 77 85 90 92 Gravel roads and parking lots 76 85 89 91 Dirt roads and parking lots .72 82 87 89 Impervious surfaces, pavement, roofs, etc. 98 98 98 98 Open water bodies: lakes,wetlands, ponds, etc. 100 100 100 Single Family Residential (2) Dwelling Unit/Gross Acre % Impervious (3) 1.0 DU/GA 15 Separate curve number 1.5 DU/GA 20 shall be selected 2.0 DU/GA 25 for pervious and 2.5 DU/GA 30 impervious portion 3.0 DU/GA 34 of the site or basin 3.5 DU/GA 38 4.0 DU/GA 42 4.5 DU/GA 46 5.0 DU/GA 48 5.5 DU/GA 50 6.0 DU/GA 52 6.5 DU/GA 54 7.0 DU/GA 56 r Planned unit developments. % impervious - condominiums, apartments, must be computed commercial business and industrial areas- (1) For a more detailed description of agricultural land use curve numbers refer to National Engineering Handbook, Section 4, Hydrology, Chapter 9, August 1972. (2) Assumes roof and driveway runoff is directed into street/storm system. (3) The remaining pervious areas (lawn) are considered to be in good condition for these curve numbers. 3.5.2-3 1190 ir � . A MINE fir► ,LA�.�� r tINN Nns, • wars►.�•�..� , l , lViE lion ' l •roe � �� '������-.��� � �� �'`:��� • In i • �..�� to` I� ,�i�ir�A., r. ` fal FIR Plop .��t all 9/4/96 2 : 0: 40 pm Barghausen Engineers page 1 MICK SANTA CHEVRON BCE #5734 FILE #5734-PRE BASIN SUMMARY BASIN ID: Al NAME: 2YR PRE-DEV RUNOFF SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1. 50 Acres BASEFLOWS: 0. 00 cfs RAINFALL TYPE. . . . : KC24HR PERV IMP PRECIPITATION. . . . : 2 . 00 inches AREA. . : 1. 50 Acres 0. 00 Acres TIME INTERVAL. . . . : 10. 00 min CN. . . . : 86. 00 0. 00 TC. . . . . 43 . 10 min 0. 00 min ABSTRACTION COEFF: 0.20 TcReach - Sheet L: 300. 00 ns: 0. 1300 p2yr: 2 . 00 s: 0. 0070 TcReach - Shallow L: 150. 00 ks:9. 00 s: 0. 0115 PEAK RATE: 0. 16 cfs VOL: 0. 11 Ac-ft TIME: 490 min BASIN ID: A2 NAME: 10YR PRE-DEV RUNOFF SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1. 50 Acres BASEFLOWS: 0. 00 cfs RAINFALL TYPE. . . . : KC24HR PERV IMP PRECIPITATION. . . . : 2 . 90 inches AREA. . : 1. 50 Acres 0. 00 Acres TIME INTERVAL. . . . : 10. 00 min CN. . . . : 86. 00 0. 00 TC. . . . . 43 . 10 min 0. 00 min ABSTRACTION COEFF: 0.20 TcReach - Sheet L: 300. 00 ns: 0. 1300 p2yr: 2 . 00 s: 0. 0070 TcReach - Shallow L: 150. 00 ks:9. 00 s: 0. 0115 PEAK RATE: 0. 34 cfs VOL: 0.20 Ac-ft TIME: 490 min BASIN ID: A3 NAME: 100YR PRE-DEV RUNOFF SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1.50 Acres BASEFLOWS: 0. 00 cfs RAINFALL TYPE. . . . : KC24HR PERV IMP PRECIPITATION. . . . : 3 .90 inches AREA. . : 1. 50 Acres 0.00 Acres TIME INTERVAL. . . . : 10. 00 min CN. . . . : 86. 00 0. 00 TC. . . . : 43 . 10 min 0. 00 min ABSTRACTION COEFF: 0. 20 TcReach - Sheet L: 300. 00 ns: 0. 1300 p2yr: 2 . 00 s: 0. 0070 TcReach - Shallow L: 150. 00 ks:9. 00 s: 0. 0115 PEAK RATE: 0. 57 cfs VOL: 0. 31 Ac-ft TIME: 490 min 9/4/96 2 : 0: 41 pm Barghausen Engineers page 2 MICK SANTA CHEVRON BCE #5734 FILE #5734-PRE BASIN SUMMARY BASIN ID: B1 NAME: 2YR POSTDEV RUNOFF SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1. 50 Acres BASEFLOWS: 0. 00 cfs RAINFALL TYPE. . . . : KC24HR PERV IMP PRECIPITATION. . . . : 2 . 00 inches AREA. . : 0. 25 Acres 1. 25 Acres TIME INTERVAL. . . . : 10. 00 min CN. . . . : 89 . 00 98 . 00 TC. . . . . 12 . 39 min 5. 09 min ABSTRACTION COEFF: 0. 20 TcReach - Sheet L: 100. 00 ns: 0. 1500 p2yr: 2 . 00 s: 0. 0200 impTcReach - Sheet L: 100. 00 ns: 0. 0110 p2yr: 2 . 00 s: 0. 0150 impTcReach - Channel L: 600. 00 kc: 42 . 00 .s: 0. 0050 PEAK RATE: 0. 68 cfs VOL: 0. 21 Ac-ft TIME: 470 min BASIN ID: B2 NAME: 10YR POSTDEV RUNOFF SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1. 50 Acres BASEFLOWS: 0. 00 cfs RAINFALL TYPE. . . . : KC24HR PERV IMP PRECIPITATION. . . . : 2 . 90 inches AREA. . : 0. 25 Acres 1. 25 Acres TIME INTERVAL. . . . : 10. 00 min CN. . . . : 89 . 00 98. 00 TC. . . . . 12 . 39 min 5. 09 min ABSTRACTION COEFF: 0. 20 TcReach - Sheet L: 100. 00 ns: 0. 1500 p2yr: 2 . 00 s: 0. 0200 impTcReach - Sheet L: 100. 00 ns: 0. 0110 p2yr: 2 . 00 s: 0. 0150 impTcReach - Channel L: 600. 00 kc: 42 . 00 s: 0. 0050 PEAK RATE: 1. 03 cfs VOL: 0. 32 Ac-ft TIME: 470 min BASIN ID: B3 NAME: 100YR POSTDEV RUNOFF SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1. 50 Acres BASEFLOWS: 0. 00 cfs RAINFALL TYPE. . . . : KC24HR PERV IMP PRECIPITATION. . . . : 3 . 90 inches AREA. . : 0. 25 Acres 1.25 Acres TIME INTERVAL. . . . : 10. 00 min CN. . . . : 89. 00 98.00 TC. . . . . 12 . 39 min 5. 09 min ABSTRACTION COEFF: 0.20 TcReach - Sheet L: 100. 00 ns: 0. 1500 p2yr: 2 . 00 s: 0. 0200 impTcReach - Sheet L: 100. 00 ns: 0. 0110 p2yr: 2 . 00 s: 0. 0150 impTcReach - Channel L: 600. 00 kc:42 . 00 s: 0. 0050 PEAK RATE: 1. 42 cfs VOL: 0.44 Ac-ft TIME: 470 min 9/4/96 2 : 0: 41 pm Barghausen Engineers page 3 MICK SANTA CHEVRON BCE #5734 FILE #5734-PRE HYDROGRAPH SUMMARY PEAK TIME VOLUME HYD RUNOFF OF OF Contrib NUM RATE PEAK HYDRO Area cfs min. cf\AcFt Acres 1 0. 162 490 4623 cf 1. 50 2 0. 343 490 8587 cf 1. 50 3 0. 565 490 13372 cf 1. 50 4 0. 680 470 8984 cf 1. 50 5 1. 031 470 13751 cf 1. 50 6 1.422 470 19108 cf 1. 50 7 0. 162 550 8995 cf 1. 50 8 0. 343 520 13758 cf 1. 50 9 0. 565 510 19117 cf 1. 50 C)/V ✓OLUMk Alt, -i 8C # 51 3 9 CA L C ULATI OAJ S__ DE TEN i/cO,,J Polly ELCV CA C5E/ VoL �CF) 1/DL CGi �� . S 91 2 - W W W W W W coo o z7. 5 1�5 ^N rNr 2� . 1 ZZoa 4, 13Z Pr o ; d S 4-1 3 �f jvF- k�AAJ F— 15: Tr- 7 L F / 5 " p;p<,. _ /07 cF 34-7 Lr- 2- P�104-Z _ 2 7 Z cF 2S5 LF 9 " � r�°Q �00 GF ¢, 7 074 L V0LUM E 10Rov1,DF- = cF 9/4/96 2 : 0: 46 pm Barghausen Engineers page 4 MICK SANTA CHEVRON BCE #5734 FILE #5734-PRE --------------------------------------------------------------------- --------------------------------------------------------------------- STAGE STORAGE TABLE CUSTOM STORAGE ID No. 1 Description: DETENTION POND STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- -------------------------------------------------------------------------------------------------------- -------------------------------------------------------------------------------------------------------- 26.50 0.0000 0.0000 27.90 2016 0.0463 29.30 4776 0.1096 30.70 5929 0.1361 26.60 115.10 0.0026 28.00 2232 0.0512 29.40 4858 0.1115 30.80 6011 0.1380 26.70 230.20 0.0053 28.10 2449 0.0562 29.50 4941 0.1134 30.90 6094- 0.1399 26.80 345.30 0.0079 28.20 2665 0.0612 29.60 5023 0.1153 31.00 6176 0.1418 26.90 460.40 0.0106 28.30 2881 0.0661 29.70 5105 0.1172 31.10 6259 0.1437 27.00 575.50 0.0132 28.40 3097 0.0711 29.80 5188 0.1191 31.20 6341 0.1456 27.10 690.60 0.0159 28.50 3314 0.0761 29.90 5270 0.1210 31.30 6423 0.1475 27.20 805.70 0.0185 28.60 3530 0.0810 30.00 5352 0.1229 31.40 6506 0.1494 27.30 920.80 0.0211 28.70 3746 0.0860 30.10 5435 0.1248 31.50 6588 0.1512 27.40 1036 0.0238 28.80 3962 0.0910 30.20 5517 0.1267 31.60 6670 0.1531 27.50 1151 0.0264 28.90 4179 0.0959 30.30 5600 0.1285 31.70 6753 0.1550 27.60 1367 0.0314 29.00 4395 0.1009 30.40 5682 0.1304 31.80 6835 0.1569 27.70 1584 0.0364 29.10 4611 0.1059 30.50 5764 0.1323 31.90 6918 0.1588 27.80 1800 0.0413 29.20 4693 0.1077 30.60 5847 0.1342 32.00 7000 0.1607 9/4/96 2 : 0:46 pm Barghausen Engineers page 5 MICK SANTA CHEVRON BCE #5734 FILE #5734-PRE STAGE DISCHARGE TABLE MULTIPLE ORIFICE ID No. 1 Description: ORIFICE STANDPIPE Outlet Elev: 26.43 Elev: 24 .43 ft Orifice Diameter: 2 .2500 in. Elev: 27 . 93 ft Orifice 2 Diameter: 3 . 0234 in. Elev: 28 . 43 ft Orifice 3 Diameter: 2 . 5313 in. STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- 26.43 0.0000 27.40 0.1353 28.40 0.3629 29.40 0.7088 26.50 0.0363 27.50 0.1421 28.50 0.4309 29.50 0.7314 26.60 0.0566 27.60 0.1486 28.60 0.4771 29.60 0.7532 26.70 0.0714 27.70 0.1548 28.70 0.5150 29.70 0.7744 26.80 0.0836 27.80 0.1608 28.80 0.5486 29.80 0.7949 26.90 0.0942 27.90 0.1666 28.90 0.5794 29.90 0.8149 27.00 0.1037 28.00 0.2378 29.00 0.6081 30.00 0.8343 27.10 0.1125 28.10 0.2798 29.10 0.6351 27.20 0.1206 28.20 0.3117 29.20 0.6608 27.30 0.1281 28.30 0.3388 29.30 0.6853 9/4/96 2 : 0: 47 pm Barghausen Engineers page 6 MICK SANTA CHEVRON BCE #5734 FILE #5734-PRE LEVEL POOL TABLE SUMMARY MATCH INFLOW -STO- -DIS- <-PEAK-> STORAGE <--------DESCRIPTION---------> (cfs) (cfs) --id- --id- <-STAGE> id VOL (cf) 2YR ROUTING .................. 0.16 0.68 1 1 27.82 7 1845.67 cf 10YR ROUTING ................. 0.34 1.03 1 1 28.32 8 2915.93 cf 100YR ROUTING ................ 0.57 1.42 1 1 28.85 9 4079.25 cf kZnto.j Cktvrdr 8/o►)LT/?4TjoN SW.9L� ; 7 � NLISo•� Q(cfs) : 0. 16200 8: n: 0. 35@00 7: 5(%). 2. 00000 6: DEPTH(ft) : 0. 33000 5: Rt .5d5: 3.00000 4: Lt .Sd5: 3.00000 3: B.WIDTH(ft ) : 1. 24448 2: V(fps): 0. 21970 1 : LWS(ft): 3. 22448 W W W x x x coo AS5tnAl; -) Zfl O aea Lws 2OC7 / = / Z 2 X ZOO CI MM M M CI s; .�� fo3 LF of,--si9ki swa �� , Lws rc, d �14 ff? 6 S- , z 7- 16 Ft 9: Q(cfs) : 0. 16200 8: n: 0. 35000 7: 5(%): 2. 00000 S 3 6: B.WIDTH(ft) : 5.30090 5: Rt.SdS: 3. 00000 4: Lt.SdS: 3.00000 3: DEPTH(ft) : 0. 16464 2: V(fps) : 0. 16983 1: LWS(ft) : 6.28782 ( ooy Cop Gc. 1� CJNecJ< ' fo c-for o, 035 Co npH�,*-4 e P 411 S"-✓-1 S (n n rt,, i sli c a\cfor © b, 3S � o ck e ✓e ` CA ry) ore- I-ec. I;stir re so /f- 9: Q(cfs) : 1 . 42000 8: n: 0.35000 7: S M : 0.50000 6: B. WIDTH(ft ) : 5. 30@00 5: Rt.SdS: 3. 00000 4: Lt .5dS: 3.00000 _ USL �. pv 3' 3: DEPTH(ft): 0.83614 2: V(fps): 0.21749 1: LWS(ft): 10.31682 VI. SPECIAL REPORT AND STUDY VII. . BASIN AND COMMUNITY PLAN AREAS oer C_ a. I SKYKOMISH RIVER � '� -- , � BASIN ''a - ;��{ — - EATkaYSww,WO- RIVER ,. P UCH ET - ti BASINAKK . u'r` South Fock oaroBes ck ', t � ` Figure E-7 --� —.. . .+ 1';." •�% mac- + ,'�` i uoo« E BASINS DRAINAG w a — a.. <.. King County _:_DRAINAGai.o'sEAnstwA¢wtkEo :385 - _° k �,C- - �'� i•� - s �.o�� Major Basin Boundary Sub-Basin Boundary 'ng County Sensitive Areas Map Folio,Wetlands Supplement qiY OF t11CAMw MI&tEASMED I _ VEFt ' BASIN 0 1 2 3 r, 7 8 tiYies 1 - J I J1 , =BEAR CREEK i ` NOQUAL'M 1 E -- jAST 1'' , ► �w- _ - �� -� E ASVL 7. KING:E� S� _ A MA AVEN HE! el 4 Figure 1 - 1 1 i a. / — �. .—. � •uovu.a.,r `a. a rouf` f'/_, �� l \\ KING COUNTY Tffm#woCOMMUNITY PLANNING AREAS King County 1985 C Wy _ :---_. - ---- - - — - - -- �` crtr or T.9DY....1EkME/7=. 1 "\ 0 1 2 3 A 5 6 7 8 MINs - Vffi: OT" EIR PERNUTS IX.- EROSION/SEDMENTATION CONTROL-DESIGN _ _ MAINTENANCE AND OPERATION MANUAL XI. MAINTENANCE AND OPERATION MANUAL This is a description of the proper maintenance needed for the detention/wet ponds for this project. The detention and wet ponds within this project are open ponds which will have a dead water storage depth of approximately three to six feet with the possibility of live storage of approximately two to three feet. To obtain access to the control structure; a 15-foot wide gravel road has been provided. It is necessary to unlock the lid and remove the cover in order to access the catch basins. Once access is obtained into the manhole, it will be necessary to remove the accumulated silt and debris within these structures. The maintenance of this facility, as well as the bottom of the pond and wetpond should occur at least on a bi-annual basis. Inspect/remove any debris that might be deposited before and after the rainy season or major storms. To remove;sediment from the cells that have standing water in it, it will be necessary to pump the water from the ponds. -Pumps can be set in the access structures which are located between the cells. A minimum three horse power sized pump should be used to remove the water from the dead storage areas of the pond facility. The pump should be up to pump from these access manholes and discharge into the biofiltration Swale area. It may be necessary to set straw bales within the swale area to keep sedimentation from migrating downstream of this system. A minimum two sets of bales should be included within the bioswale prior to this pump water discharging into the stream. The on-site storm drainage pipe conveyance system will need to be inspected periodically in accordance with the 1990 King County Drainage Manual (see attached). Remove any trash, debris, or sedimentation build-up which could block free flow of surface water runoff on an annual basis as a minimum, as well as in the event of any unusual conditions such as a blockage or flooding conditions. The biofiltration swale will also need scheduled maintenance in accordance with the 1990 King County Drainage manual. Trash and debris exceeding one cubic foot per 1,000 square feet of the ditch shall be cleared and removed from the biofiltration swale. All accumulated sediment which exceeds 20 percent of the design depth, approximately 0.1 feet of accumulated depth shall be removed from the biofiltration swale. Inspection and maintenance of the biofiltration swale should be completed using the same schedule as for the ponds. -12- 3313.015 [HPG/tbl KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL MAINTENANCE REQUIREMENTS FOR PRIVATELY MAINTAINED DRAINAGE FACILITIES NO. 1 - PONDS Maintenance Conditions When Maintenance Results Expected Component Defect is Needed When Maintenance is Performed General Trash &Debris Any trash and debris which exceed 1 Trash and debris cleared from site. cubic foot per 1000 square feet (this is about equal to the amount of trash it would take to fill up one standard size office garbage can). In gE.-ieral, there should be no visual evidence of dumping. Poisonous Any poisonous vegetation which may No danger of poisonous vegetation where Vegetation constitute a hazard to County personnel County personnel or the public might or the public. Examples of poisonous normally be. (Coordination with vegetation include: tansy ragwort, poison Seattle/King County Health Department) oak,stinging nettles,devils club. Pollution Oil,gasoline,or other contaminants of No contaminants present other than a one gallon or more or any amount found surface film. (Coordination with that cou;d: 1)cause damage to plant, Seattle/King County Health Department) animal,or marine life; 2)constitute a fire hazard; or 3) be flushed downstream during rain storms. Unmowed Grass/ tf facility is located in private residential When mowing is needed,grass/ground Ground Cover area,mowing is needed when grass cover should be mowed to 2 inches in exceeds 18 inches in height. In other height. areas,the general policy is to make the pond site match adjacent ground cover and terrain as long as there is no interference with the function of the facility. Rodent Holes Any evidence of rodent holes if facility is Rodents destroyed and dam or berm acting as a dam or berm,or any evidence repaired. (Coordination with Seattle/ of water piping through dam or berm via King County Health Department) rodent holes. Insects When insects such as wasps and hornets Insects destroyed or removed from site. interfere with maintenance activities. Tree Growth Tree growth does not allow maintenance Trees do not hinder maintenance access or interferes with maintenance activities. Selectively cultivate trees such activity(i.e.,slope mowing, silt removal, as alders for firewood. vectoring or equipment movements). If trees are not interfering with access, leave trees alone. Side Slopes of Erosion Eroded damage over 2 inches deep Slopes should be stabilized by using Pond where cause of damage is still present or appropriate erosion control measure(s): where there is potential for continued e.g., rock reinforcement, planting of erosion. grass, compaction. Storage Area Sediment Accumulated sediment that exceeds 10% Sediment cleaned out to designed pond of the designed pond depth. shape and depth; pond reseeded if necessary to control erosion. Pond Dikes Settlements Any part of dike which has settled 4 Dike should be built back to the design inches lower than the design elevation. elevation. Emergency Rock Missing Only one layer of rock exists above native Replace rocks to design standards. Overflow/Spillway soil in area five square feet or larger, or any exposure of native soil. A-1 1/90 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL NO. 2 - INFILTRATION Maintenance Conditions When Maintenance Results Expected Component Defect Is Needed When Maintenance is Performed General Trash &Debris See'Ponds" Standard No. 1 See "Ponds Standard No. 1 Poisonous See "Ponds' Standard No. 1 See"Ponds Standard No. 1 Vegetation Pollution See"Ponds'Standard No. 1 See "Ponds Standard No. 1 Unmowed Grass/ See "Ponds'Standard No. 1 See 'Ponds Standard No. 1 Ground Cover Rodent Holes See"Ponds"Standard No. ! See "Ponds Standard No. 1 Insects See"Ponds"Standard No. 1 See"Ponds Standard No. 1 Storage Area Sediment A percolation test pit or test of facility Sediment is removed and/or facility is Indicates facility is only working at 90%of cleaned so that infiltration system works its designed capabilities. according to design. Sheet Cover Sheet cove.Is visible and has more than Sheet cover repaired or replaced. (If Applicable) three 1/44nch holes in it. Sump Filled With Any sediment and debris filling vault to Gean out sump to design depth. Sediment and 10%of depth from sump bottom to Debris (If bottom of outlet pipe or obstructing flow Applicable) into the connector pipe. Filter Bags Filled with Sediment and debris fill bag more than Replace filter bag or redesign system. Sediment and 1/2 full. Debris ,ock Filters Sediment and By visual inspection little or no water Replace gravel in rock filter. Debris flows through filter during heavy rain storms. A-2 1/90 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL NO. 3 - CLOSED DETENTION SYSTEMS (PIPES/TANKS) Maintenance Conditions When Maintenance Results Expected Component Defect Is Needed When Maintenance Is Performed Storage Area Plugged Air Vents One-half of the cross section of a vent is Vents free of debris and sediment. blocked at any point with debris and sediment. Debris and Accumulated sediment depth exceeds All sediment and debris removed from Sediment 10%of the diameter of the storage area storage area. for 1/2 length of storage vault or any point depth exceeds 15% of diameter. Example: 72-inch storage tank would require cleaning when sediment reaches depth of 7 inches for more than 1/2 length of tank. Joints Between Any crack allowing material to be All Joints between tank/pipe sections are Tank/Pipe Section transported into facility. sealed. Tank/Pipe Bent Any part of tank/pipe is bent out of shape Tank/pipe repaired or replaced to design. Out of Shape more than 10%of its design shape. Manhole Cover not in Place Cover is missing or only partially in place. Manhole is closed. Any open manhole requires maintenance. Locking Mechanism cannot be opened by one Mechanism opens with proper tools. Mechanism Not maintenance person with proper tools. Working Bolts into frame have less than 1/2 inch of thread (may not apply to self-locking lids). Cover Difficult to One maintenance person cannot remove Cover can be removed and reinstalled by Remove lid after applying 80 pounds of lift. Intent one maintenance person. is to keep cover from sealing off access to maintenance. Ladder Rungs Kng County Safety Office and/or Ladder meets design standards and Unsafe maintenance person judges that ladder is allows maintenance persons safe access. unsafe due to missing rungs, misalignment, rust,or cracks. Catch Basins See 'Catch Basins'Standard No. 5 See'Catch Basins"Standard No.5 A-3 1/90 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL NO. 4 - CONTROL STRUCTURE/FLOW RESTRICTOR Maintenance Conditions When Maintenance Results Expected Component Defect Is Needed When Maintenance Is Performed General Trash and Debris Distance between debris build-up and All trash and debris removed. (Includes bottom of orifice plate is less than 1-1/2 Sediment) feet. Structural Damage Structure is not securely attached to Structure securely attached to wall and manhole wall and outlet pipe structure outlet pipe. should support at least 1,000 pounds of up or down pressure. Structure is not in upright position (allow Structure in correct position. up to 10%from plumb). Connections to outlet pipe are not Connections to outlet pipe are watertight; watertight and show signs of rust. structure repaired or replaced and works as designed. Any holes—other than designed holes— Structure has no holes other than in the structure. designed holes. Cleanout Gate Damaged or Cleanout gate is not watertight or is Gate is watertight and works as designed. Missing missing. Gate cannot be moved up and down by Gate moves up and down easily and is one maintenance person. watertight. Chain leading to gate is missing or Chain is in place and works as designed. damaged. Gate is rusted over 50%of its surface Gate is repaired or replaced to meet area. design standards. Orifice Plate Damaged or Control device is not working properly Plate is in place and works as designed. Missing due to missing,out of place, or bent orifice plate. Obstructions Any trash,debris,sediment,or vegetation Plate is free of all obstructions and works blocking the plate. as designed. Overflow Pipe Obstructions Any trash or debris blocking (or having Pipe is free of all obstructions and works the potential of blocking) the overflow as designed. pipe. Manhole See "Closed Detention Systems" Standard See 'Closed Detention Systems"Standard No.3. No.3. Catch Basin See "Catch Basins"Standard No. 5. See "Catch Basins"Standard No. 5. A-4 I/90 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL NO. 5 - CATCH BASINS Maintenance Conditions When Maintenance Results Expected Component Defect Is Needed When Maintenance Is Performed General Trash &Debris Trash or debris of more than 1/2 cubic No trash or debris located immediately in (Includes foot which is located immediately in front front of catch basin opening. Sediment) , of the catch basin opening or is blocking capacity of basin by more than 10%. Trash or debris (in the-basin) that No trash or debris in the catch basin. exceeds 1/3 the depth from the bottom of basin to invert of the lowest pipe into or out of the basin. Trash or debris in any inlet or outlet pipe Inlet and outlet pipes free of trash or blocking more than 1/3 of its height. debris. Dead animals or vegetation that could No dead animals or vegetation present generata odors that would csuso within the catch basin. complaints or dangerous gases (e.g., methane). Deposits of garbage exceeding 1 cubic No condition present which would attract foot in volume. or support the breeding of Insects or rodents. Structural Damage Corner of frame extends more than 3/4 Frame is even with curb. to Frame and/or inch past curb face into the street (if Top Slab applicable). Top slab has holes larger than 2 square Top slab is free of holes and cracks. inches or cracks wider than 1/4 inch (intent is to make sure all material is running into the basin). Frame not sitting flush on top slab, i.e., Frame is sitting flush on top slab. separation of more than 3/4 inch of the frame from the top slab. Cracks in Basin Cracks wider than 1/2 inch and longer Basin replaced or repaired to design Walls/Bottom than 3 feet,any evidence of soil particles standards. entering catch basin through cracks,or maintenance person judges that structure is unsound. Cracks wider than 1/2 inch and longer No cracks more than 1/4 inch wide at the than 1 foot at the joint of any inlet/outlet joint of inlet/outlet pipe. pipe or any evidence of soil particles entering catch basin through cracks. Settlement/ Basin has settled more than 1 inch or has Basin replaced or repaired to design Misalignment rotated more than 2 inches out of standards. alignment. Fire Hazard Presence of chemicals such as natural No flammable chemicals present. gas,oil, and gasoline. Vegetation Vegetation growing across and blocking No vegetation blocking opening to basin. more than 10%of the basin opening. Vegetation growing in inlet/outlet pipe No vegetation or root growth present. joints that is more than six inches tall and less than six inches apart. Pollution Nonflammable chemicals of more than No pollution present other than surface 1/2 cubic foot per three feet of basin film. length. A-S I/90 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL NO. 5 - CATCH BASINS (Continued) Maintenance Conditions When Maintenance Results Expected Component Defect Is Needed When Maintenance Is Performed Catch Basin Cover Cover Not in Place Cover is missing or only partially in place. Catch basin cover is closed. Any open catch basin requires maintenance. Locking Mechanism cannot be opened by one Mechanism opens with proper tools. Mechanism Not maintenance person with proper tools. Working Bolts into frame have less than 1/2 inch of thread. Cover Difficult•o One maintenance person cannot remove Cover can be removed by one Ren love lid after applying 80 lbs.of lift; intent is maintenance person. keep cover from sealing off access to maintenance. Ladder Ladder Rungs Ladder is unsafe due to missing rungs, Ladder meets design standards and Unsafe misalignment,rust,cracks, or sharp allows maintenance person safe access. edges. Metal Grates Grate wit`,opening wider than 7/8 inch. Grate openings meet design standards. (if applicable) Trash and Debris Trash and debris that is blocking more Grate free of trash and debris. than 20%of grate surface. Damaged or Grate missing or broken member(s) of Grate is in place and meets design Missing the grate. standards. A-6 I/90 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL NO. 6 - DEBRIS BARRIERS (e.g. Trash Racks) Maintenance Conditions When Maintenance Results Expected Component Defect Is Needed When Maintenance Is Performed General Trash and Debris Trash or debris that is plugging more Barrier clear to receive capacity flow. than 20%of the openings in the barrier. Metal Damaged/Missing Bars are bent out of shape more than 3 Bars In place with no bends more than Bars inches. 3/4 inch. Bars are missing or entire barrier is Bars in place according to design. missing. Bars are loose and rust is causing 50% Repair or replace barrier to design deterioration to any part of barrier. standards. A_7 1/90 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL NO. 7 - ENERGY DISSIPATORS Maintenance Conditions When Maintenance Results Expected Component Defect Is Needed When Maintenance is Performed External: Rock Pad Missing or Moved Only one layer of rock exists above native Replace rocks to design standard. Rock soil in area five square feet or larger, or any exposure of native soil. Dispersion Trench Pipe Plugged with Accumulated sediment that exceeds 20% Pipe cleaned/flushed so that it matches Sediment of the design depth. design. Not Discharging Visual evidence of water discharging at Trench must be redesigned or rebuilt to Water Properly concentrated points along trench (normal standard. condition is a'sheet flow"of water along trench). Intent is to prevent erosion damage. Perforations Over 1/2 of perforations in pipe are Clean or replace perforated pipe. Plugged plugged with debris and sediment. Water Fjws Out Maintenance person observes water Facility must be rebuilt or redesigned to Top of'Distributor' flowing out during any storm IAss than standards. Catch Basin the design storm or it is causing or appears likely to cause damage. Receiving Area Water in receiving area is causing or has No danger of landslides. Over-Saturated potential of causing landslide problems. Internal: Manhole/Chamber Worn or Damaged Structure dissipating flow deteriorates to Replace structure to design standards. Posts, Baffles, 1/2 or original size or any concentrated Sides of Chamber worn spot exceeding one square foot which would make structure unsound. Other Defects See'Catch Basins'Standard No. 5 See"Catch Basins" Standard No. 5 A_8 1/90 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL NO. 8 - FENCING Maintenance Conditions When Maintenance Results Expected Component Defect Is Needed When Maintenance is Performed General Missing or Broken Any defect in the fence that permits easy Parts in place to provide adequate Parts entry to a facility. security. Parts broken or missing. Broken or missing parts replaced. Erosion Erosion more than 4 inches high and 12- No opening under the fence that exceeds 18 inches wide permitting an opening 4 inches in height. under a fence. Wire Fences Damaged Parts Posts out of plumb mo.e than 6 inches. Posts plumb to within 1-1/2 inches. Top rails bent more than 6 inches. Top rail free of bends greater than 1 inch. Any part of fence (including posts, top Fence is aligned and meets design rails,and fabric)more than 1 foot out of standards. design alignment. Missing or loose tension wire. Tension wire in place and holding fabric. Missing or loose barbed wire that is Barbed wire in place with less than 3/4- sagging more than 2-1/2 inches between inch sag between posts. posts. Extension arm missing, broken,or bent Extension arm in place with no bends out of shape more than 1-1/2 inches. larger than 3/4 inch. Deteriorated Paint Part or parts that have a rusting or scaling Structurally adequate posts or parts with or Protective condition that has affected structural a uniform protective coating. Coating adequacy. Openings in Fabric Openings in fabric are such that an 8- No openings in fabric. inch-diameter ball could fit through. A-9 1/90 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL NO. 9 - GATES Maintenance Conditions When Maintenance Results Expected Component Defect is Needed When Maintenance Is Performed General Damaged or Missing gate or locking devices. Gates and locking devices in place. Missing Members Broken or missing hinges such that gate Hinges intact and tubed. Gate is working cannot-be easily opened and closed;by a freely. maintenance person. Gate Is out of plumb more than 6 inches Gate is aligned and vertical. and more than 1 foot out of design alignment. lAissing stretcher bar, stretcher bands, Stretcher bar, bands, and ties in place. and ties. Openings in Fabric See'Fencing'Standard No.8 See 'Fencing' Standard No. 8 A-10 1/90 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL NO. 10 - CONVEYANCE SYSTEMS (Pipes & Ditches) Maintenance Conditions When Maintenance Results Expected Component Defect Is Needed When Maintenance Is Performed Pipes Sediment& Debris Accumulated sediment that exceeds 20% Pipe cleaned of all sediment and debris. of the diameter of the pipe. Vegetation Vegetation that reduces freq movement of All vegetation removed so water flows water through pipes. freely through pipes. Damaged Protective coating is damaged; rust is Pipe repaired or replaced. causing more than 50%deterioration to any part of pipe. Any dent that decreases the cross section Pipe repaired or replaced. area of pipe by more than 20%. Open Ditches Trash &Debris Trash and debris exceeds 1 cubic foot Trash and debris cleared from ditches. per.1,000 square feet of ditch and slopes. , Sediment Accumulated sediment that exceeds 20% Ditch cleaned/flushed of all sediment and of the design depth. debris so that it matches design. Vegetation Vegetation that reduces free movement of Water flows freely through ditches. water through ditches. Erosion Damage to See"Ponds" Standard No. 1 See "Ponds" Standard No. 1 'Slopes Rock Lining Out of Maintenance person can see native soil Replace rocks to design standard. Place or Missing (If beneath the rock lining. Applicable) Catch Basins See"Catch Basins' Standard No. 5 See "Catch Basins" Standard No.5 Debris Barriers See"Debris Barriers" Standard No.6 See "Debris Barriers" Standard No.6 (e.g.,Trash Rack) A-11 1/90 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL NO. 11 - GROUNDS (Landscaping) Maintenance Conditions When Maintenance Results Expected Component Defect Is Needed When Maintenance Is Performed General Weeds Weeds growing in more than 20%of the Weeds present in less than 5% of the (Nonpoisonous) landscaped area (trees and shrubs only). landscaped area. Safety Hazard Any presence of poison ivy or other No poisonous vegetation present in a poisonous vegetation. landscaped area. Trash or Utter Paper,can, bottles,totalling more than 1 Area clear of litter. cubic foot within a landscaped area (trees and shrubs only)of 1,000 square feet. Trees and Shrubs Damage Umbs or parts of trees or shrubs that are Trees and shrubs with less than 5%of the split or broken which affect more than total foliage with split or broken limbs. 25%of the total foliage of the tree or shrub. Trees or shrubs that have been blown Tree or shrub in place.tree of iniury. y down or knocked over. Trees or shrubs which are not adequately Tree or shrub in place and adequately supported or are leaning over,causing supported; remove any dead or diseased exposure of the roots. trees. A-12 I/90 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL NO. 12 - ACCESS ROADS/EASEMENTS Maintenance Conditions When Maintenance Results Expected Component Defect Is Needed When Maintenance Is Performed General Trash and Debris Trash and debris exceeds 1 cubic foot Trash and debris cleared from site. per 1,000 square feet, i.e., trash and debris would fill up one standard size garbage can. Blocked Roadway Debris which could damage vehicle tires Roadway free of debris which could (glass or metal). damage tires. Any obstructions which reduce clearance Roadway overhead clear to 14 feet high. above road surface to less than 14 feet. Any obstructions restricting the access to Obstruction removed to allow at least a a 10-to 12-toot width for a distance of 12-foot access. more than 12 feet or any point restricting access to less than a 10-foot width. Road Surface Settlement, When any surface defect exceeds 6 Road surface uniformly smooth with no Potholes, Mush Inches in depth and 6 square feet in area. evidence of settlement, potholes, mush Spots, Ruts In general,any surface defect which spots,or ruts. hinders or prevents maintenance access. Vegetation in Road Weeds growing in the road surface that Road surface free of weeds taller than 2 Surface are more than 6 inches tall and less than inches. 6 inches apart within a 400-square-toot area. Shoulders and Erosion Damage Erosion within 1 foot of the roadway more Shoulder free of erosion and matching Ditches than 8 inches wide and 6 inches deep. the surrounding road. Weeds and Brush Weeds and brush exceed 18 inches in Weeds and brush cut to 2 inches in height or hinder maintenance access, height or cleared in such a way as to allow maintenance access. A-13 1/90