Loading...
Storm Drainage Report - Plaza Drive«r "w - .~ ~ , .~, r a ... :~ ~~ STORM DRAINAGE REPORT FOR PLAZA DRIVE J~JLY 17, 2003 eK. Engineeringd STORM DRAINAGE REPORT FOR PLAZA DRIVE A part of Section 30, Township 17 North, Range 2 East of the Willamette Meridian City of Yelm, Thurston County, Washington Prepared for: ~ ~~~ ~ ~ ~11A ,.~~'~; ~-~ Prepared by: .~ • ^, ~ ~ ~c, Mr. Larry Schorno ~~; ~(~ ~ ~~~ ~ ) c~ = Apex Engineering PLLC Rocky Prairie Development Co. ~ 2601 South 35th, Suite 200 P.O. Box 480 ~ , ~, `• - Tacoma, Washington 98409 Yelm, Washington 98597 ~~ ~~G~ p ,;,~"~, ~ ,~.~ ~' (253) 473-4494 (360) 458-7788 `~ ~ `' • .~ <~ File #25507/0 `~ • ; ,`~x~ ~ 7 D3 July 17, 2003 I Project Engineer: ~~;, ;~~.~~' ~ ~~1 ;. ~~;!, _ ~,,_ James Gaertner, E.LT. Project Manager: Geo y Sherwin, P.E. ..,t_ P. _~r~~ p9ex "I hereby state that this Storm Drainage Report for Plaza Drive has been prepared by me or under my supervision and meets the standard of care and expertise which is usual and customary in this community for professional engineers. I understand that the City of Yelm does not and will not assume liability for the sufficiency, suitability, or performance of drainage facilities prepared by me." ~9inPPri~ TABLE OF CONTENTS Page Section I Project Overview ............................................................................................................... l Section II Plot Plan ............................................................................................................................. 1 Section III Preliminary Conditions Summary .................................................................................... 1 Section IV Off-Site Analysis ............................................................................................................... 1 Section V Analysis and Design .......................................................................................................... l Section VI Special Reports and Studies .............................................................................................. 2 Section VII Basin and Community Planning Areas ............................................................................ 2 Section VIII Other Permits ..................................................................................................................... 2 Section IX Erosion and Sediment Control Plan ................................................................................. 2 Section X Maintenance and Operations Manual ............................................................................... 3 Appendices: Appendix A Drainage Calculations Appendix B Maintenance Appendix C Geotechnical Report P9ex SECTION I -- PROJECT OVERVIEW The Plaza Drive project is a proposed storm drainage system for the Plaza Drive right-of--way. The proposed road is approximately 1.64 acres and is bound between Yelm Avenue (S.R. 507) and 103`d Street S.E. The road is located within a portion of Section 30, Township 17 North, Range 2 East, Willamette Meridian, within the City of Yelm, Thurston County, Washington. Plaza Drive will be improved to meet the City of Yelm's current standards. The stormwater from Plaza Drive will be conveyed to a biofiltration Swale and an infiltration pond, located on the neighboring Prairie Plaza Short Plat. The biofiltration Swale was sized for the 6- month/24-hour design storm, with capacity for the 100-year/24-hour storm. The infiltration pond was sized fora 100-year/24-hour design storm. SECTION II -- PLOT PLAN Construction drawings for the proposed road improvements and drainage system have been prepared and are to be submitted in conjunction with the short plat.. SECTION III -PRELIMINARY CONDITIONS SUMMARY The existing Plaza Drive consists of approximately 26 feet of pavement with asphalt thickened edge on both sides. There is also an existing water system within the roadway. At present, there is no existing storm conveyance system for the road. SECTION IV -OFF-SITE ANALYSIS Since stormwater runoff for the 100-year/24-hour design storm will be infiltrated on site, no runoff is expected to leave the site. The surrounding parcels are either undeveloped or they have been developed, handle their runoff and the respective parcels. SECTION V -ANALYSIS AND DESIGN Existin Sg_ ite Hydrology The existing 60-foot easement contains the existing roadway and scotch broom. There is no stormwater conveyance system to handle the runoff from the existing roadway. The precipitation used to model the site has been taken from isopluvials of the DOE Stormwater Management Manual. p9ex Developed Site Hydrolo~y The right-of--way for Plaza Drive was determined to be the basin for the proposed road. As future development occurs on the proposed short plat, a separate system for each lot will be provided. Some of the future development will capture some of the runoff from Plaza Drive; however, the runoff quantity and quality systems were sized for the whole Plaza Drive Basin. The storm facilities for the road improvements are required to be located outside of the proposed road right-of--way. The basin calculations are provided in Appendix A. The proposed drainage concept meets the D.O.E. Manual. The D.O.E. Manual states that all infiltration (and filtration) BMPs must be preceded by pretreatment such as a bioswale or sediment tank. Treatment for this project will be provided by a biofiltration Swale preceding the infiltration facilities. The Swale will be sized for bioswale function for the 6-month/24-hour storm, and for capacity for the 100-year/24-hour storm. The infiltration pond was designed for a 100-year/24-hour storm. A maximum infiltration rate of 20 inches per hour was used. This rate includes the required safety factors. The drainage calculations are provided in Appendix A. As can be seen from the required storage and the outflow hydrographs, the proposed system is adequate. SECTION VI -SPECIAL REPORTS AND STUDIES A Geotechnical analysis of the site has been prepared. Refer to Appendix C. No other special reports or studies are known to have been prepared for the site. SECTION VII -BASIN AND COMMUNITY PLANNING AREAS The site in not known to be located within any special basin or community planning area. Storm water discharge from the site is to the ground and is designed in accordance with BMPs of the Department of Ecology Storm Water Management Manual for the Puget Sound Basin. SECTION VIII -OTHER PERMITS No other special permits are anticipated for the road improvements. SECTION IX -EROSION AND SEDIMENT CONTROL PLAN Little or no erosion is anticipated for and during construction of the proposed development. However, the storm drainage and grading plans will incorporate the following erosion control BMPs: 1. Stabilize Construction Entrance - A gravel construction driveway will be placed at the entrance off of Plaza Drive. The construction entrance should limit the amount of mud and sediment transported onto public roadways. 2 p9ex 2. Catch Basin (CB) Sediment Barrier -Filter Fabric inlet barriers will be placed at all CBs to limit the amount of sediment being carried into the infiltration systems. 3. Filter Fabric Fence -Filter fabric fence will be placed along the downstream perimeters to protect adjacent property owners. Fence lengths and locations will be shown on the construction drawings. SECTION X -MAINTENANCE AND OPERATIONS MANUAL Maintenance will be required for the storm facilities to perform as intended. Maintenance of the on-site infiltration and filtration facilities will be provided by the project proponent. Appendix B identifies some maintenance guidelines for the conveyance system and infiltration systems. The maintenance guidelines were obtained from the King County Surface Water Design Manual and will be given to the project proponent to ensure maintenance of the proposed storm system. U25507/doc s-rpts/tptsJ g071703 3 p9ex APPENDIX A DRAINAGE CALCULATIONS FIGURE E.4 Isopluvials of 100 Year, 24-Hour precipitation in Tenths of an Inch ~~ ~ :_~~~ aj _ ~ _ ,1 ~ 6 ao , 4 ~< ~ J s~~ ~ ~ 'as :, ~' , {~ l.. ~ `~ ~ . ~ . . ~ ~ ~, 5 ~ ^ y~ 1 \y~ ~ ~ r ,~. 't ~. ~, 5~ S If / _~ - _--COMA --- - ~-..__. ~~ 6~ ~ ---~,~ ' T ~ 5,, •.~ a ~~. 20 ~ .~ :4 ~- ~ -.2 ~. ~,- ,~ 'a Z ~ s ~ _ ~~ = ' mac. ~~, l5 ` _ ' -~( - - J 65~ J ~' ~~2 _ so C 60~ ~`' - ~70 ~ ~ S - E-12 FIGURE E.1 Isopluvials of 2-Year, 24-Hour Precipitation in Tenths of an Inch 3 , EFrr -~ ,~ ~ 24 ~~ ~ -` ,~ ~ ~ ^ ~ ~ it - - r ~ i . ~t~" ~= ~~ 4~ ~~ , ~3? ~ ~5 1 `'i -..r y ~ :c 35 L5~) ~ ` 35 ~ T SAT ~ ~ -, ~ - - ~ ~ e l ~ ~ " ~~ ~ ; ~,•- / 1 35; ``-- ss~ ~ ~ ~ - ~ - - ~ i COMA ~ _~-- ~ ;s ~ - X35 ~ - \ J ,3R3c :1 . 1, '~ l ~' g 7 ~ ~ ; O ~ 30 ~ ~ ` ~ 35 ` ~3`. -,L.~. `~ / (~ ~.' ~ ~.~,~(5 • ~. ~ t 4~ S . Cam: ~ , • CENT . , - ~. ~~ (~'~3a , ~, _ .,.. ~ i ~. `'tea--- ~_ ~_ - `_~_-_: ~ ~.\` -~ ~ ~ ~~ 3 , .) c5 c E-9 Plaza Drive File# 25507/0 Date: July 1, 2003 DEV-24hr Event Summary: BasinlD Peak Q Peak T Peak Vol Area Method Prec. Raintype Event (cfs) (hrs) (ac-ft) ac /Loss in DEV-24hr 0.57 8.00 0.1884 1.64 SBUH/SCS 1.6 TYPEIA 6mo DEV-24hr 1.88 8.00 0.6510 1.64 SBUH/SCS 2.5 TYPE1A 100 yr Drainage Area: DEV-24hr Hyd Method: SBUH Hyd Loss Method: SCS CN Number Peak Factor 484 00 SCS Abs: 0.20 Storm Dur 24.00 hrs Area CN TC Pervious 0.0000 ac 78.00 0.28 hrs Impervious 1.6400 ac 98.00 0.08 hrs Total 1.6400 ac Supporting Data: Impervious CN Data: Prairie Ptaza Drive 98.00 1.6400 ac Pervious TC Data: Flow type: Description: Length: Slope: Coeff: Travel Time Sheet Prototype tc just to have something 300.00 ft 10.00% 0.1700 16.91 min Impervious TC Data: Flow type: Description: Length: Slope: Coeff: Travel Time Fixed None Entered 0.00 ft 0.00% 5.0000 5.00 min DEV-7day Event Summary: BasinlD Peak Q Peak T Peak Vol Area Method Prec. Raintype Event (cfs) (hrs) (ac-ft) ac /Loss in DEV-7day 0.85 55.00 1.4428 1.64 SBUH/SCS 11 PC7DAY 7day Drainage Area: DEV-7day Hyd Method: SBUH Hyd Loss Method: SCS C N Number Peak Factor 484 00 SCS Abs: 0.20 Storm Dur 168.00 hrs Area CN TC Pervious 0.0000 ac 78.00 0.28 hrs Impervious 1.6400 ac 96.34 0.08 hrs Total 1.6400 ac Supporting Data: Impervious CN Data: Prairie Plaza Drive 96.34 1.6400 ac Pervious TC Data: Flow type: Description: Length: Sheet Prototype tc just to have something 300.00 ft Impervious TC Data: Flow type: Description: Length: Fixed None Entered 0.00 ft Slope: Coeff: Travel Time 10.00% 0.1700 16.91 min Slope: Coeff: Travel Time 0.00% 5.0000 5.00 min FOR: FILE NO. ~.~ 8 ~.3 2601 South 35th, Suite 200 (.r /~; ~ C~J vs ~ vv~ e n ~ TASK No. Tacoma, Washington 98409 (253) 473-4494 PAGE Engineering° Fax: (253) 413-0599 PREPARED BY: DATE: ' OF a s s.C CHECKED BY: J. S, C, SCALE: ~ ~ -----_- _ _ _ _ ~ _ _ ~ _. _ _ _ _ _ - {_ t ~ ~ __ ---- ' ~ { _ WATER QUALITY DESIGN Project: File# P-1 BIOSWALE CALCULATIONS Prairie Plaza Drive 25507 Q6mo= P-2 Slope= P-3 Vegetation= Desi gn Steps (D): D-1 Depth= D-2 n= D-3 Shape= 0.57 cfs 0.01 ft/ft Grass-Legumes 0.333 ft 0.07 Trapezoidal Side Slope= 3 :1 D-4 Calculated Bottom Width 6= (n*Q/((1.49`y^5/6*S^0.5)-Z"y)) Bottom Width= 0.67 ft MIN Top Width = By x Zy^2= 2.67 ft D-5 Calculated Area Area= By+Zy^2= 0.56 SF D-6 Calculated Velocity 0.67 ft Used V= Q/A= 1.02 fps <1.5 .:. Ok STABILITY CHECK Project: Prairie Plaza Drive File# 25507 SC-1 0100= 1.88 cfs slope= Runoff larger than 6 month will pass through the bioswale SC-2 Vegetation= good SC-3 Degree of Retardance= D =LOW SC-4 Vmax = 4 ft/s SC-5 trial n= 0.038 SC-6 VR= 4.1 ft"2/s SC-7 R=VRNmax= R= 1.025 SC-8 VRact= 4.09 SC-9 Within 0.35% .:. OK SC-10 V=VR/R= 3.99 ft/s <Vmax .:. OK SC-11 Area=0100N = 0.47163 SF SC-12 0.47163451 SF <0.56 SF .:. OK CO-1 Length= 100 ft Prop= 2 Area= 1.11 sf b= 2.348427 ft ~ ~. ~ rT US ~ +~ T= 4.346427 ft CO-2 No check dams needed fora 1 % slope BIOSWALE SUMMARY Length= 100 Ft Bottom Width= 2.35 Ft Top Width= 4.35 Ft Depth= 0.333 Ft Area = 1.11 SF Side Slope= 3 :1 0.01 INFILTRATION POND Running 1:\25507\Storm-Shed\CS Report.pgm on Wednesday, July 02, 2003 Summary Report of all RLPooI Data Project Precips [6mo] 1.60 in [2 yr] 2.50 in [10 yr] 3.50 in [25 yr] 4.00 in [100 yr] 5.00 in [7 day] 11.00 in BASLIST2 [DEV-24hr] Using [TYPE1AJ As [100 yr] BasinlD Peak Q Peak T Peak Vol Area Method Raintype Event (cfs) (hrs) (ac-ft) ac /Loss DEV-24hr 1.8835 8.00 0.6510 1.64 SBUH/SCS TYPE1A 100 yr BASLIST [TYPE1A] AS [100 yr] DETAILED [DEV-24hr] Drainage Area: DEV-24hr Hyd Method: SBUH Hyd Loss Method: SCS CN Number Peak Factor: 484.00 SCS Abs: 0.20 Storm Dur 24.00 hrs Area CN TC Pervious 0.0000 ac 78.00 0.00 hrs Impervious 1.6400 ac 98.00 0.08 hrs Total 1.6400 ac Supporting Data: Impervious CN Data: Prairie Plaza Drive 98.00 1.6400 ac Impervious TC Data: Flow type: Description: Length: Slope: Coeff: Travel Time Fixed None Entered 0.00 ft 0.00°/a 5.0000 5.00 min HYDLIST SUMMARY [OUT-100yr] HydID Peak Q Peak T Peak Vol Cont Area ------- (cfs) (hrs) (ac-ft) (ac) OUT-100yr 0.34 5.17 0.6520 1.6400 STORLIST [Infiltration Pond] Node ID: Infiltration Pond Desc: Infiltration Pond Start EI: 100.0000 ft Max EI: 104.5000 ft Contrib Basin: Contrib Hyd: Length ss1 ss2 Width ss3 ss4 27.5000 ft 3.OOh:1v 3.OOh:1v 27.0000 ft 3.OOh:1v 3.OOh:1v Bottom area only with infiltration DISCHLIST [STA-DIS] Control Structure ID: STA-DIS -Stage Discharge rating curve Descrip: Stage Discharge Start EI Max EI Increment 100.0000 ft 105.0000 ft 0.10 Stage Discharge 100.0000 ft 0.3437 cfs 105.0000 ft 0.3437 cfs RLPCOMPUTE [CS] SUMMARY 100 yr Match Q: 0.0000 cfs Peak Out Q: 0.3437 cfs -Peak Stg: 103.97 ft -Active Vol: 0.14 acft SUMMARY OF RESULTS Pond Length: 27.5 ft Pond Width: 27 ft Pond Depth w/out freeboard: 4 ft ex Engineering; FOR: 2601 South 35th, Suite 200 Tacoma, Washington 98409 (253) 413-4494 Fax: (253) 413-0599 PREPARED BY: ~ ~' ;y;~ DATE: x . CHECKED BY: SCALE: N;' --,~-. PAG E I OF ,_ _ _ ,_ e ~ r ~ _.... __ - __. . ._ t s .. ~ ~ _ ~ _ __ ; ~__..____.. i _.__-__. _._.._.. -.....j r .... _. _-.. _.. _... -___. __ -_. -. _ _ .- .. ... ....__.._ .. -- ~ f ... 4 1 ; j ~ ~ ~ 4 ____ t - I _ _ _ r ~ __- ' I t ~ .. j rI t i . -.. ( _...--_-._ .. a._____... _ -. _ .... .. ..... ~ ~_- i i ~... ~ .... _. .. -. + - 25-YEAR CONVEYANCE MA W Ug W ~ w ~ ~N wu U ~ v .~ ~~ g Q Z Q m D Q i r ~S ~ i I ~` ,; W ~~ I~ ~' Z cn, N ,, QI Ln Q r ,J~ ~L' `, ~ ~ ~~~ z %'~ ~~~~ ~~ . - %- , m ~ !~, ~ ~I j.~ -_ 34 48, ~ t ~ ~. ~~ -~ Z G% ,~ Cn MQ W 349 MA i ~; Z Q W ~-. ~ - ~--343 ° ~- ~' -~ ~. ~~ ~ ,. ~ ~~ ,y~o~- ...._. I~ N ~ ~ ~~~ ,~, ! \ I _ o' lF, I I) 5 ~ ~. { ~ 1 ~ J i ~ (`- J 1 ~ i~ l I i ' i _ - tiAS ~-- __ 1 weos~ - " _ ~_ _ ~` - ;. Olld O O1 ~ C7 N^Q •c ~ o~~ d ~g~ n '~ CC M O N C •' C X N~~ v 3 N ~~ O ~ F ~ ~\ n N v L05SZ Project Precips [6mo] 1.60 in [2 yr] 2.50 in [10 yr] 3.50 in [25 yr] 4.00 in [100 yr] 5.00 in [7 day] 11.00 in BASIN 1 Event Summary: BasinlD Peak Q Peak T Peak Vol Area Method ------- (cfs) (hrs) (ac-ft) ac /Loss BASIN 1 0.39 8.00 0.1349 0.43 SBUH/SCS BASIN 1 0.49 8.00 0.1707 0.43 SBUH/SCS Drainage Area: BASIN 1 Hyd Method: SBUH Hyd Peak Factor: 484.00 Storm Dur 24.00 hrs Area Pervious 0.0000 ac Impervious 0.4300 ac Total 0.4300 ac Supporting Data: Impervious CN Data: SUB BASIN 1 Plaza Drive Impervious TC Data: Flow type: Description: Fixed None Entered Raintype Event TYPEIA 25 yr TYPEIA 100 yr Loss Method: SCS CN Number SCS Abs: 0.20 CN TC 78.00 0.00 hrs 98.00 0.08 hrs 98.00 0.4300 ac Length: Slope: 0.00 ft 0.00% Coeff: Travel Time 5.0000 5.00 min Raintype Event TYPEIA 25 yr TYPEIA 100 yr BASIN 2 Event Summary: BasinlD Peak Q Peak T Peak Vol Area Method ------- (cfs) (hrs) (ac-ft) ac /Loss BASIN 2 0.37 8.00 0.1286 0.41 SBUHISCS BASIN 2 0.47 8.00 0.1627 0.41 SBUHISCS Drainage Area: BASIN 2 Hyd Method: SBUH Hyd Peak Factor: 484.00 Storm Dur 24.00 hrs Area Pervious 0.0000 ac Impervious 0.4100 ac Total 0.4100 ac Supporting Data: Impervious CN Data: SUB BASIN 2 Plaza Drive Impervious TC Data: Flow type: Description: Fixed None Entered Loss Method: SCS CN Number SCS Abs: 0.20 CN TC 78.00 0.00 hrs 98.00 0.08 hrs 98.00 0.4100 ac Length: Slope: Coeff: Travel Time 0.00 ft 0.00% 5.0000 5.00 min BASIN 3 Event Summary: BasinlD Peak Q Peak T Peak Vol Area ------- (cfs) (hrs) (ac-ft) ac BASIN 3 0.22 8.00 0.0753 0.24 BASIN 3 0.28 8.00 0.0953 0.24 Drainage Area: BASIN 3 Hyd Method: SBUH Hyd Peak Factor: 484.00 Storm Dur 24.00 hrs Area Pervious 0.0000 ac Impervious 0.2400 ac Total 0.2400 ac Supporting Data: Impervious CN Data: SUB BASIN 3 Plaza Drive Impervious TC Data: Flow type: Description: Fixed None Entered Method Raintype Event /Loss SBUHISCS TYPEIA 25 yr SBUHISCS TYPEIA 100 yr Loss Method: SCS CN Number SCS Abs: 0.20 CN TC 78.00 0.00 hrs 98.00 0.08 hrs 98.00 0.2400 ac Length: Slope: 0.00 ft 0.00% BASIN 4 Event Summary: BasinlD Peak Q Peak T Peak Vol Area ------- (cfs) (hrs) (ac-ft) ac BASIN 4 0.26 8.00 0.0878 0.28 BASIN 4 0.32 8.00 0.1111 0.28 Drainage Area: BASIN 4 Hyd Method: SBUH Hyd Peak Factor: 484.00 Storm Dur 24.00 hrs Area Pervious 0.0000 ac Impervious 0.2800 ac Total 0.2800 ac Supporting Data: Impervious CN Data: SUB BASIN 4 Plaza Drive Impervious TC Data: Flow type: Description: Fixed None Entered Method /Loss SBUHISCS SBUHISCS Coeff: Travel Time 5.0000 5.00 min Raintype Event TYPEIA 25 yr TYPEIA 100 yr Loss Method: SCS CN Number SCS Abs: 0.20 CN TC 78.00 0.00 hrs 98.00 0.08 hrs 98.00 0.2800 ac Length: Slope: Coeff: Travel Time 0.00 ft 0.00% 5.0000 5.00 min BASIN 5 Event Summary: BasinlD Peak Q Peak T Peak Vol Area ------- (cfs) (hrs) (ac-ft) ac BASIN 5 0.26 8.00 0.0878 0.28 BASIN 5 0.32 8.00 0.1111 0.28 Drainage Area: BASIN 5 Hyd Method: SBUH Hyd Peak Factor: 484.00 Storm Dur 24.00 hrs Area Pervious 0.0000 ac Impervious 0.2800 ac Total 0.2800 ac Supporting Data: Impervious CN Data: SUB BASIN 5 Plaza Drive Impervious TC Data: Flow type: Description: Fixed None Entered Method Raintype Event /Loss SBUH/SCS TYPEIA 25 yr SBUHISCS TYPEtA 100 yr Loss Method: SCS CN Number SCS Abs: 0.20 CN TC 78.00 0.00 hrs 98.00 0.08 hrs 98.00 0.2800 ac Length: Slope: Coeff: Travel Time 0.00 ft 0.00% 5.0000 5.00 min ROUTEHYD [] THRU [PLAZA DRIVE] USING TYPEIA AND [25 yr] NOTZERO RELATIVE Reach Area Flow Full Q % Full nDepth Size nVel fVel CBa51n I Hyd ----- ac cfs cfs ratio ft ---- ft/s fUs ------------ P-3 0.4300 0.3932 3.0127 0.13 0.2440 12" Diam 2.6506 3.8359 BASIN 1 P-2 0.4300 0.3932 3.0127 0.13 0.2440 12" Diam 2.6506 3.8359 P-7 0.2800 0.2560 3.0127 0.08 0.1970 12" Diam 2.3392 3.8359 BASIN 4 P-9 0.2800 0.2560 3.0127 0.08 0.1970 12" Diam 2.3392 3.8359 BASIN 5 P-8 0.2800 0.2560 3.4875 0.07 0.1833 12" Diam 2.5934 4.4404 P-6 0.5600 0.5120 3.5134 0.15 0.2579 12" Diam 3.1912 4.4734 P-5 0.2400 0.2194 3.0127 0.07 0.1827 12" Diam 2.2347 3.8359 BASIN 3 P-4 0.8000 0.7315 6.3625 0.11 0.2289 12" Diam 5.3953 8.1010 P-1 1.6400 1.4995 3.0724 0.49 0.4930 12" Diam 3.8883 3.9119 BASIN 2 TO-BIO 1.6400 1.4995 3.0127 0.50 0.4987 12" Diam 3.8316 3.8359 ..--- .--.. Rch App Bend Junct HW Max EI/ ----- ----- Loss Head Loss Loss Elev Rim EI From Node To Node ft k ft k ft ft DUMMY 334.6440 CB-1 DUMMY 335.0789 0.2348 0.0011 ------ 334.8452 342.7700 CB-2 CB-1 335.2488 0.4520 0.5570 0.1600 335.5138 342.7700 CB-3 CB-2 336.3598 0.1091 0.1392 ------ 336.3899 339.1800 CB-4 CB-3 336.5298 ------ ------ ------ 336.5298 339.1800 CB-5 CB-2 341.3239 0.1581 0.0020 0.0467 341.2145 345.0200 CB-7 CB-5 342.4151 0.1044 0.0011 0.0577 342.3695 346.1800 CB-8 CB-7 342.4587 ------ ------ ------ 342.4587 346.1800 CB-9 CB-7 343.6349 0.0850 0.1131 ------ 343.6630 347.5300 CB-10 CB-9 343.8087 ------ ------ ------ 343.8087 347.5300 CB-6 CB-5 341.3085 ------ ------ ------ 341.3085 345.0200 CB-9 CB-7 CB-5 CB-2 CB-3 100-YEAR CONVEYANCE ROUTEHYD ~ THRU [PLAZA DRIVE] USING TYPEIA AND [100 yr] NOTZERO RELATIVE Reach Area Flow Full O % Full nDepth Size nVel fVel CBasin I Hyd ----- ac cfs cfs ratio ft ••-- fUs ft/s ------------ P-3 0.4300 0.4939 3.0127 0.16 0.2738 12" Diam 2.8301 3.8359 BASIN 1 P-2 0.4300 0.4939 3.0127 0.16 0.2738 12" Diam 2.8301 3.8359 P-7 0.2800 0.3216 3.0127 0.11 0.2206 12" Diam 2.4997 3.8359 BASIN 4 P-9 0.2800 0.3216 3.0127 0.11 0.2206 12" Diam 2.4997 3.8359 BASIN 5 P-8 0.2800 0.3216 3.4875 0.09 0.2052 12" Diam 2.7722 4.4404 P-6 0.5600 0.6432 3.5134 0.18 0.2897 12" Diam 3.4065 4.4734 P-5 0.2400 0.2756 3.0127 0.09 0.2043 12" Diam 2.3903 3.8359 BASIN 3 P-4 0.8000 0.9188 6.3625 0.14 0.2568 12" Diam 5.7627 8.1010 P-1 1.6400 1.8835 3.0724 0.61 0.5659 12" Diam 4.1093 3.9119 BASIN 2 TO-BIO 1.6400 1.8835 3.0127 0.63 0.5729 12" Diam 4.0479 3.8359 ----- ----- Rch App Bend Junct HW Max EI/ .-.-. ..-.- Loss Head Loss Loss Elev Rim EI From Node To Node ft ft ft ft ft k DUMMY 334.7098 CB-1 DUMMY 335.1902 0.2622 0.0012 ------ 334.9293 342.7700 CB-2 CB-1 335.3601 0.5157 0.6355 0.1825 335.6624 342.7700 CB-3 CB-2 336.4052 0.1244 0.1587 ------ 336.4396 339.1800 CB-4 CB-3 336.5752 ------ ------ ------ 336.5752 339.1800 CB-5 CB-2 341.3903 0.1802 0.0023 0.0533 341.2656 345.0200 CB-7 CB-5 342.4683 0.1193 0.0013 0.0659 342.4161 346.1800 CB-8 CB-7 342.5345 ------ ------ ------ 342.5345 346.1800 CB-9 CB-7 343.6705 0.0970 0.1291 ------ 343.7026 347.5300 CB-10 CB-9 343.8444 ------ ------ ------ 343.8444 347.5300 CB-6 CB-5 341.3735 ------ ------ ------ 341.3735 345.0200 CB-9 Cg-7 CB-5 Cg_p CB-3 APPENDIX B MAINTENANCE KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL MAINTENANCE REQUIREMENTS FOR PRIVATELY MAINTAINED DRAINAGE FACILITIES N0.1-PONDS Maintananaa Campa»nt 0s}act Condltiona WMn Marnunana 4 Nssded Resufb Ezpsctsd Whsn Maintananu b Psrfarmsd Gsnsfd Trash k Oebris Any trash end debns «hich exceed 1 cubic Trash and debris cleared from foot per 1,000 aquara leer (this is about equal site. tc :he amount of [rear it would take to fill up ana ataMard size office garbage cant. In general, there should de no visud evidence of dumping. Poisonaw Any poisonous vegetanon which may Nc danger of poisonous Vegetation constitute a hazard tc County peraannal or the vegetation where County public. Examples o! poisonous vegetation peraannal ar the public might include: tansy regwa rt, poison oak, aanpinq normally ba. (Coordination with nerdee, devils ciuo. SeettleiKinq Ccunry Health DepermenU Pollution OiI, gasoline, ar other :ontaminante of one No contaminants present other gallon or more or any mount found that than a mrfeca film. (Coordination could: 11 cause demege to plant, animal, or with Seer'ellCnq County Health marine life; 2) constitute a fire hazard; or Departmentl 3) be flushed downsveam during rdn rtartns. Utntowsd Grass/ I} facility is loea[ed in privets rssidentid area, When mowing is needed, Ground Cover mowing is needed when grass ezceeds 18 grass/grqund cover should ba inches in height. In other erects, the ganerd mowed to 2 inches in height. policy is to make the pond dte match adjacent ground cover end tertdn as loop sa there is no in[er}erence with the function of the facility. Rodent Holes Any evidence of rodeo[ holes it facility is Rodents destroyed and darn or acting es a dam ar bartn, or any evidence o} bartn repaired. (Coordination with water piping through dam or berm via rodent Saettia/King County Hael[h holes. Department) (rostra When insects fuck act wasps end hornets Insects deavcyed or rempvad interfere with maintenance activities. from site. Troe Growth Trea growth does not dlaw mdntsnance Trees da not hinder maintenance aecees or interferes with maintenance aetiviry activities. Selectively eultivete q.e., dope mowing, tilt ramovd, vectoring, ar Veas such es ddero for firewood. equipment movementfl. If Vees ere not interfering with access, leave Vees done. Side Slopes of Erodon Eroded demege over 2 inches deep where Slopes should he stabilized by pond ewse of damage is still present or where uainq appropriate erosion convol there is potential for continued erosion. meeeurelsl; e.q., rock reinforcement, planting of press, compaction. Storage Arw Sediment Accumulated sediment that exceeds 10% of Sediment cleaned out to designed the dedgned pond depth. pond fhepe and depth; pond reseeded if necessary to convol erosion. Pond Dikes Settlements ~ Any pert of dike which has fettled 4 inches Dike should be built back to the lower than the design elevation. design elevation. Errorpsney Rock Mlssinq Only one layer of rock ezista above native soil Replace rocks to design Ovsrflow/Spllwey in ere five square feet or larger, or any atanderda. exposure of native soil. A-1 uroa `f KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL NO. 2 -INFILTRATION Maintenance t:onditlons When Maintanena Results Expected When Component Defect !s Needed Maintenance b Performed General Trash & Debris See 'Ponds' Standard No. 1 See 'Ponds' Standard No. 1 Poisonous See "Ponds" Standard No. 1 Sae 'Ponds" Standard No. 1 Vegetation Pollution See 'Ponds" Standard No. 1 See 'Ponds" Standard No. 1 Unmowed Grass/ See "Panda" Standard No. 1 See "Ponds' Standard No. 1 Ground Cover Rodent Holes See 'Ponds" Standard No. 1 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 indicates facility is only working at 90°6 of its facility is cleaned so that designed capabilities. If twa inches or more infiltration system works sediment is present, remove. according to design. Sheet Cover (If Sheet cover is visible and has more that three Sheet cover repaired or replaced. Applicable) 1/flinch holes in it. Sump Filled with Any Sediment and debris filling vault to 10°6 Clean out sump to design depth. Sedmiment and of depth from sump bottom to bottom of Debris llf Applicable) outlet pipe or obstructing flow into the connector pipe. Filter Gaga Filled with Sediment and debris fill bag more than 1/2 Replace filter bap or redesign Sedmiment and full. system. Debris Rock Flters Sediment end Debris By visual inspection, little or no water flows Replace gravel in rock filter. through filter during heavy rain storms. Side Slopes of Erosion See 'Ponds' Standard No. 1 See "Ponds' Standard No. 1 Pond Emergency Rock Missing See "Ponds' Standard Na. 1 Overflow Spillway Settling Ponds and Sediment Remove when i3" or mare. Vaults Note: Sediment accumulation of more than .25 inches per year may indicate excessive erosion is occurring upstream of the facility or that conveyance systems are not being properly maintained. The contributing drainage area should be checked for erosion problems or inadequate maintenance of conveyance systems if excessive sedimentation is noted in an infiltration facility. Check twice s year during first 2 years of operation; once a year thereafter. Clean manholes/catch basins, repair damaged inletsloutleta, clean fresh racks. A-2 11/94 ~5 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN Ni.=;~:JA'. NO. 3 -CLOSED DETENTION SYSTEIIAS (PIPES/TANKS) Malrttenanee CondWons Y1Rten Maintenance pesutts ExpaCed Carrfponertt Defect is Needed YVhen Maintenanes Is Perforated Storage Area Plugged Ait Vents Cne-half of ;he cress section of a vent is blocked at any point Kith debris and sediment. Debris and A~umulated sediment depth exceeds Sediment 10% of the diameter of its storage area for 1/2 Length of storage vauK or arty paint depth exceeds 15% of diameter. Example: 72-inch sicraCe tank would require cleaning when sediment reaches depth cf T inches to mere than 1/2 length cf ;ank. Joints Between Any crack allowing material ;o be Tank/Pipe Section transpcred into facility. Tank/Pfpe Sent Any par, of +ank; pipe s bent out of shape Cut of Shape mare than 10'6 of its design shape. Manhole Cover not in Place Cover is missing or only partially in place. Any ccen manhole requires maimanance. Locking Mechanism cannot be opened 5y one Mechanism Not maintenance pencn with proper :eots_ Working Bolts into frame have !ess than t/2 inch of threaC (may net aptly to self-;poking lids). Cover Di~cuft io Cne maintenance person cannot remove Remove lid after aFpryin4 ~ rounds of lift. Intent is to keep cover frcm sealing off access to maintenance. !.adder Rungs tGng County Safety Cftica and/or Unsafe maintenance person ;edges that ladder is unsafe due to missing rungs, misalignment, nisi, or cracks. Catett Basins See 'Catch i3asins' Standard No. 5 Vents free of deoris ;nC -°d`.-,°^'. All sediment and deoris removed frcm storage area AlI joints between tank; pice sac:icr•s era sealed. Tank/pine repaired or replaced to .esiyn. Manhole is dosed. McCtanism opens with prncer cis. Cover can be removed and reinstalled by one maintenance person. ladder meets design standards and allows maintenance persons sale ac: ass. See 'Catch 2asins' Standard No. 5 A-3 I ~ / KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL NO. 5 -CATCH BASINS Maintenanu Condttlona When Maintenance Results Expettsd Component De(ee! la Needed When Maintenance la Performed General Trash ~ Debris Trash or debris of more than t/2 cubic No Vash 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 (n :he basin) that No Vash or debris in the Catch basin. exceeds 1/3 the depth frcm the bottom of basin to invert of 7te 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 t /3 of its height. debris. Dead animals or vegetation that could No dead animals or vegetation present generate odors that would cause within the catch basin. complaints or dangerous gases (e.g., methane). Deposits of garbage exceeding 1 cubic No ccnditicn present which wculd attraC toot in volume. or support the breeding of inseCS or rodents. Structural Damage Corner of',rame extends mcre than 3/4 Frame is even with curb. to Frame and/or inch past curb face into the street (if Top Stab 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 rep~acad or repaired to design Walls/Bottom titan 3 feet, any evidence of soil particles standards. entering catch basin through cracks, or maintenance person judges that structure is unsound. Cracks wider than t/2 inch and longer No cracks more than 1/4 inch wide at ~e than 1 foot at the jcint cf any inlet/outlet joint of inlet/outlet pipe. pipe or any evidence of soil particles entering catch basin dtrough 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. Fre 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-5 1/90 ~~ KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL NO. 5 -CATCH 8AS1NS (Continued) Malntenanu CondNfone When MaMtenanee Result Expected Component pe}ect b PMeded When Maintenance Is Performed Catch Basin Cover Cover Not in Place Cover is missing or only partially in place. Gtch basin cover is Uosed. Any open catch basin requires maimsnana. Locking Mechanism cannot be opened by one Mechanism opens with proper tools. Mechanism Not mairttsnana person with proper tools. Working Bolts into frame haw less than t/2 inch of thread. Cover Difficult to One maintenance person cannot remove Cover can be removed by one Remove lid after applying 80 Its. 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 with opening wider than 7/8 inch. Grata openings meet design standards. (f applicable) Trash and Debris Trash and debris that is blocking more Grate free of Vash and debris. than 2096 of grate surfaa. Damaged or Grate missing or broken member(s) of Grate is in place and meets design Missing the grate. standards. A-6 1/'90 ~~ KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL NO. 6 -DEBRIS BARRIERS (e.g. Trash Racks) Maintenance CondHlata When Maintenance Resells EspeeLed Component Defect b Needed When Maintenance Is Performed Genera! Trash and Debris Trash or debris that is plugging more Barrier clear to receive capacity flaw. than 20% of the openings in the barrier. Metal Camaged/ Missing Bars are bent out of shape more than 3 gars inches. Bars are missing or entire barrier is missing. Bars are loose and rust is causing 50% deterioration to any part of barrier. Bars in place with no bends more than 3/4 inch. Bars in place according to design. Repair or replace barrier to design standards. - A-7 I/90 ~~ KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL NO. 7 -ENERGY DISSIPATORS _ Malntsnana Conditlona When Maintenance Reaufta Expected Component Defect fa Needed When Malnt~nance la 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 2C% Pipe leaned/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 ±o Water Property concentrated points along trench (normal standard. condition is a 'sheet flow' of water along trench). Intent is to prevent erosicn damage. Perforations Over 1/2 of perforations in pipe are Lean or replace perforated pipe. Plugged plugged with debris and sediment. Water Flows Out Maintenance person observes water Facility must be rebuiR or redesigned to Top of 'Distributor' flowing out during any storm less than standards. Catclt 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. intemal• Manhole/Chamber Wom or Damaged Structure dissipating flow deteriorates to Posts, Baffles, t/2 or original size or any concenVated Sides of Chamber wom spot exceeding one square foot which would make structure unsound. Other Defects See 'Catch Basins' Standard No. 5 Replace structure to design standards. See 'Catch Basins' Standard No. 5 A-8 1/50 ~b KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL NO. 8 -FENCING Maintenance Condltforta When Malntenana Resutta Expected Component Defect b Needed When Maintenance is Performed General Mlsaing or Broken Any defect in the fence that permits easy Parts in place to provide adequate pis entry to a facility. security. Parts broken or missing. Broken or missing parts replaced. Erosion Wire Fences Damaged Parts Deterloratsd Paint or Protective Coating Openings in Fabric Erosion more than 4 inches high and 12- 18 inches wide permitting an opening under a fence. Posts out of plumb more than 8 inches. Top rails bent more than 6 inches. Any part of fence Including posts, top rails, and fabric) more than 1 foot out of design alignment. Missing or loose tension wire. Missing or loose barbed wire that is sagging more than 2-1/2 inches between posts. Extension arm missing, broken, or bent out of shape mare than 1-1/2 inches. Part or parts that have a rusting or scaling condition that has affected structural adequacy. Openings in fabric are such that an & inch-diameter ball could fit through. fUo opening under the fence that exceeds 4 inches in height. Posts plumb to within t-1/2 inches. Top rail free of bends greater than 1 inch. Fence is aligned and meats design standards. Tension wire in place and hclding !abric. Barbed wire in place with Tess than 3/~- inch sag between posts. Extension arm in place with no bends larger than 3/4 inch. Structurally adequate posts or parts with a uniform protective coating. lYo openings in fabric. A-9 1N0 ~~ KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL NO. 10 -CONVEYANCE SYSTEMS (Pipes & Ditches) Malrrtsnanca CondWons When Maintenance Results Expected Component Defect Is Needed When Malrrtenanq Is Performed Pipes Sediment 8~ Debris Accumulated sediment that exceeds 20% Pipe cleaned of all sediment and debris. of the diameter of the pipe. Vegetation Vegetation that reduces free movement of AJI vegetation removed so water flows water through pipes. freely through pipes. Damaged Protec5ve 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 seC.ion Pipe repaired or replaced. area of pipe by more than 20%. Cpen Citches Trash ~ Debris Trash and debris exceeds t cubic foot Trash and debris cleared from ditches. per 1,000 square feet of ditch and slopes. Sediment Accumulated sediment that exceeds 20% Citch 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 1Vo. 1 Slopes Rock Lining Out of Maintenance person can see native soil Replace rocks to design standard. Place or Missing (tf beneath the rock lining. A{tplicable} Catch Basins See 'Catch Basins' Standard fJo. 5 See 'Catch Basins' Standard No. 5 Cebris Barriers See 'Debris Barriers' Standard No. 6 See 'Debris Barriers' Standard fro. o" (e.g., Trash Rack) A-il 1190 ~~ KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL O. 11 -GROUNDS (Landscaping) - Mairrtenanee Component Delve! Candltloru When Malrttatr+anee b Needed Results Expected WMn Maintenance Is Performed General Weeds Weeds growing in more than 2096 of the Weeds present in less than 5% of the (Nonpoisonous) landscaped area (trees and shrubs only). landscaped area. ~}ety Hazard Any prosencs of poison ivy or other No poisonous vegetation prosent in a poisonous vegetation, landscaped area. Trash or Litter Paper, eon, bottles, totalling more tha- 1 Area clear of litter. cubic foot within a landscaped aroa (tries and shrubs only) of 1,000 square feet yes and Shrubs Damage Limbs or parts of trees or shrubs that are Trees and shrubs with less than 5% of the spilt or broken which affec! more than total foliage with split or broken Ilmbs. 25% of the total foUage of the tree or shrub. Trees or shrubs that have been blown Tres or shrub in place free of injury. down or knodcsd over. Trees or shrubs which aro not adequately Trss or shrub in place and adequately wpported or are leaninfl over, causing supported; remove any dead or diseased exposure of the roots. trees. - A-12 1/90 ~~ KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL NO. 12 -ACCESS ROADS/EASEMENTS Malrrtenana Conditions When Malntenana Rewlts Experled Component Defeei is Needed When Malrttertana fa Performed General Trash and Debris Trash and debris exceeds 1 cubic foot Trash and debris deared 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 dearance Roadway overhead dear to 14 feet high. above road wrfacs to less than 14 feet. Any obstructions restricting the access to CbstruC.ion removed to allow at least a a 10• to 12-foot 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 Rcad 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 wrface defect which spots, or ruts. hinders or prevents maintenance access. Vegetation in Rcad Weeds growing in the road surface that Road surface free of weeds tailor than 2 Surface are more than 6 inches tall and less than inches. 6 inches apart within a 400-square-foal area. Shoulders and Erosion Damage Erosion within t foot of the roadway more Shoulder free of erosion and matching Ditches than 8 inches wide and 6 inches deep. the wrrounding road. Weeds and &ush Weeds and brush exceed 18 inches in Weeds and brush cut to 2 inches in height or hinder maintenance access. height or dsated in wch a way as to allow maintenance access. A-13 I/g0 ~4 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL NO. 4 -CONTROL STRUCTURE/FLOW RESTRfCTOR Malntenana Condtttons `Nhert Maintenance Reautts EzD~cted C.~mponent Defect Ia Needed When Ma(ntsnanes !a Performed General C,eanout Gate orifice Plate ~rerflow Pipe Llanhole Catch Basin Trash and Debris (Indudes Sediment) SttuCsuai Damage Damaged or Missing Damaged or Missing Obstructions Obstructions Distance between debris build-up and bottom of orifice plats is less Mart 1-t/2 feet. StruCalre is not securely attached to manhole wall snd outlet pipe suuaure should wpport at least 1,000 pounds of up or dawn preawre. Structure is not in upright position (allow up to 10% from plumb). Cannecticns :o outlet pipe are not watertight and show signs of nisi Any hcles - oL'ter than designed holes - in the structure. Geanaut gate is not +vatartignt cr is missing. Gate cannot be moved up and down by one maintenance perscrt. Gtiain leading :o gate is missing or damaged. Gate is rusted over 50°i of its wrface area. Control device is not worlcirrg property due b missing, out of place, ar bent orifice plats. Any trash, debris, sediment, or vegetation blocking the plate. Any trash or debris blocking (or having U1e potential of blacking) the overflow pipe. Sae 'C:osed ~etantion Systems' Standard Plo. 3. See 'Catch Zasins' Standard No. 5. all lash and debris removed. Stru~.ure securely attac~ed :o wail and outlet pipe. Struc r~re in xrrec: acsiticn. G;nnecacrts 'o outlet pipe era watarighr. sirueture reoaired or reciacad and ~.vcrks as designed. Structure has no holes other than designed hoes. Gate is ~,ratertight and .vcrks as designed. Gate moves up and down easily and is watertight G'tain is in place and works as designed. Cate is repaired or replaced to meet' design standards. Plate is in place arnd works as designed. Plats is free of all obstructions and works as designeC. Fps is free of all obstructions and woks as designed. See 'C:csad ~etenticn Systems' Standard hio. 3. Ses 'Catch 3asins" Standard !Va. 5. A~ 1/9~ KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL JO. 9 -GATES Malrrtenana Conditions When Malrtbnanee Results Expeebd Component Defect b Needed When Mlalr>t.nana 1a Performed General Damaged or Missing gate or Iodcing devices. Gates and iodcing devices in place. Missing Members 8roksn or missing hinges wch that pats Mnges intact and lubad. Gets is working cannot bs easily opened and dosed by a freely. maintsnanw person. Gate is out of plumb maro than 6 inches and more than t foot out of design alignment. Mlasinq stretcher bar, stretcher bands, and ties. Openings In Fabric See 'Fencing' Standard No. 8 Gate is aligned and vertical. Stretcher bar, bands, and ties (n place. See 'Fendng' Standard iVO. 8 A-10 I/90 ~~ ~~ Engineering; FOR: 2601 South 3Sth, Suite 200 ~ ~~~ ~'(~ P ~~ Z ~+ Tacoma.Washington 98409 C t-~,41.( -~(C L (~~I (/ ll.~ (25's) 473.4494 Fax: (253) 473-0599 PREPARED BY: ~! ,~j , I DATE: 7 ~j ~ i CHECKED BY: I SCALE: 255~~ ~ TASK NO. i PAGE -Ti i OF ------ -- I ' ' -~ - - ~ ~PP~-~d~~. ``r _ _._ ~ ---- - - - - - . -- -- --- •- .. -r ------ - i --~.~ . P~'~.__~-~--'`~ o ~ =- -~tJ~-~ ~C~~4_~-~-~~~ ~ w~__ ~~~ PAC ~~ fl~ ~c h l~ Lc ~ ~ ~ U~ ~ ~>L~_ l.. A'~.(E .__ w~L -- - ~ ~~ ~ - I-.I~t - ~1P- =r 'L'~i „_ ~I _ -~ . ' ~ ~rZ~ __ t-- T- -- -- --- - -._ _ -- - --- ~, ~, -- -. 1 I ' I '__ . - - --- -, - -- _ _ __~ -- t- __ ~~~-L~~(, ~_Z.~L ~,_1~E_(~ ~7~(N1~c~_ 1_C"iJ-~. ~ Ft~ ---Jt~t -- ~ ~-~-`~-----_ ~ -- -;_ --- ---- ----' i I -- I -- -- -~ - - --_ _-- - - -- I- i-- ~ _` - ~-------- I ------ --- ~_~ -_.~___ ~ i I ~ ' 1- _! ___....-_.-- _.._ .__._~ --_ _ __ - - --- - ---- ---- -- _._- ~------------ - - _ - ----- _ _- ----- - - - I I ~ __ ~ - i ----- _ -- ___ - ---- +- -- _. _ _ r -: -- _-_ _ -- _ - i I ~ i i ~ j ~ i ~ ----- j ~ i ~ ~ i , ~ -- ._ i _ 1 i ~- -- ~ i 1 I I i i i - ~ ' I I ~) i ~ ~ ! i - I li! ~ ~I Till IIII lil -i Iii 1111 !III " ~ j I I I i i I! I lntersacfion v - v - L~~ ~ L ... tom. G1 ~ N ~ .. N '17 U y t 7] N ~ L w-' O ~`~ O O' ~. y + y N N '/~ L L u~ '~ t •- C N - N - N W. - - 7 Cl O ~- N ~ U L •-~ ~ ~- L 3l O y •#~~- L~ c[~;O ?n 7 O `~ Z ~- E - a a v C Jl i1 ~ t G O~ O O w E O ~, ti rn ~- •. i O ~p y O m0 ~p ~ N7?1 <3 ~ N w w O O 2 .I Qi C v d aN ~ r v 0 C '`L G `- r C+ C v L CJ G F- O O 1 \` 3 `I J YI 3' .. I ~ L L L O 1 - J J 1 G W L < ~ ^ 1~ G n y' ~~ '~°I i ~ i t N N U C ~ ~ ~ y I V C1 J N C - ~ I ~L Y y ] ~ ~ o C~.1 °L ~ G N -. O n ~ ~- ... ~ `J x ~- u r, C ¢~ 1 ~ -_ G O ~ Q~ n m 'L N ~~~ 3 t 4 L, y ~ ~~ ; ~, ~ ~- a i _ m y C rn O T.. V1 . C - L S 41 C ~ ^' ~ H C ~O O 2 I Z~ QtO 4 - - ~~ i!f ~ ~ n 4 } y Z ~ C ,F 1 I ~ _ C~ N I y N 7 J_ ~~i y, ~.... C N ~ -~ ~ ~,_ j ~ ~1 I/ \ i ~~ ~ ~ \~ ~ / ------------= "y- ~---~=~------ Channelization Widening Figure 910-8a v ~`-- ya: n = ~ ~ v - --'n- C^ r :1 -' U . ~ - ~;._ --x- .~ _ _ - ~ J 3 3 - - 's ~' i y ~ i ~ yJ ~ ~ ~_ =ii I ~~O ;~` ~ ~ ~, N ~ N ~ L C. 5 I ~ ~- t- L. I ~- \ I / / / - ` 1 yf ~ yl I ~~^ ( I n~ ~.. c y ~ ,rv~Q~.O;, 1~ ~D LLI MJ~Cn ~• J ... .. 7 - - - L*J _ - __- y = _ = = E - N m J Ci l(~ O V i 'J l(7 ~ U 7 -- S te. T '1 f^ ~ V ~ y ° e - n a• ; ~ u~ u- - , - Page 91Q 40 Design Manual . _ March 1994 ~ 7~~~ "7)~ APPENDIX C GEOTECHNICAL REPORT GEORESOURCES LLC 253 638 899c 05/15/03 09:18pm P. 001 ~~~~~~~ ~'~~5~ 7l_l~~ P't~.2Sa.279-1423 Sk l3 d'';~Citic NIw3~. [?., Skc. t-d lFx.253-G38-5992 >Fi#'~e, `~VaslMi~a~tt~n 9~~l24-2G49 May 13, 20C)J F?ocky Prairie Development Center c/o Apex Engineering 2601 South 35th Street Suite 2rJ0 Tacoma. i~/A 98409 Attention: Mr. Geoff Scherwin stormwater Report °rairie Plaza Site Algiers Drive Yelm, 111lashing#on File No:PrairiePlaza.' P iiV T ~~C+DUCTI~N This report presents the results o~ our geotechnical services for the proposed storm~R~ater infiltration system to be located in the so~.rth portion of the project site and adjacent area. Individual infiltration systems will be located at the sites. The Prairie Plaza site will consist of a residential structure and associated parking and driveway areas. T1ie site is located north of Algiers Drive in Yelm, Washington. Our services are provided at your request Cur understanding of the project is based on our discussions with you, our previous +n~ork in the prpjert area and our site obseniations and our test pit explorations. The proposed site layout and location of the stormwater detention facilities arc shown on the Site Plan, Figure 1. The puroose of our services is to evaluate the subsurface conditions at the pond site to determine design infiltration rates for on-site storm v~rater infiltration. Specifically, our scope of services includes the following: 1. Review the available geologic, soil and ground water data relevant to the site. This includes the existing test pits data. 2. Conduct a geologic reconnaissance or` the site area. 3. Monitor the excavation of backhoe ~.est pits at the approximate locations of the proposed stormwater infiltration systems. 4. Evaluate the subgrade soil conditions at the proposed detention pond location and a minimum of 3 feet belo~N the bottom of the proposed infiltration systems. 4. Provide stormwater infiltration rags for the native soils at the proposed locations of the stormwater infiltration systems based on current regulations, as appropriate. SURFACE CONt]i!TiONS SITE ;:QnIQITlOn15 The site is located in the south portion of the Mr,Kenna-Yefm glacial upland area. The site is bounded by Algiers Drive on the south. An existing structure and out buildings are located east and southwest of the property. The site is flat to gently sloping to the northwest_ Slopes in the site area are generally less than 3 percent. No surface water was obser~~ed at the site at itle time of our site visits. UrJe understand that isolated avetland areas occur southeast of the site. The genera! topography of the site area indicates that most of the site drains to the northwest. GEORESOURCES LLC 259 888 8992 05115/03 09:18pm P. 002 Prairie Plaza - Yelm May 13, 2003 Page 2 SITE GEC)LOGY The site is generally situated ~nritl~iri tho McN:eEina-Yelm glacial upland area and outwash plane. The existing topography, as well as tine suriici3E and shallow subsurface soils in the area, are the result of the most recent ',/ashon ;;tale of the Fraser glaciation that occurred between about 12.000 and 15,000 years ago, and weathering and erosion that has occurred since. The near surface soils at the site consist of discontinuous layers of stratified sand and gravel outwash that was deposited b}r runoff from the ~~ashon glacial ice. The outwash, where present, is underlain by unstratified, nonsorted glacial till consisting of silt, sand, gravel, cobbles and boulders that was deposited directly beneath and over-ridden by the advancing glacial ice. S0.lBSt1RFAGE ~EXPL013ATI~tJNS Subsurface conditions of the site ~rvFrrc previously evaluated by excavating 4 backhoe test pits to depths of 11.0 to 12.0 feet below the existing site grades. Soils were visually evaluated and sampled. A description of the method used to classify the soils is included as Figure 2. Copies of the test pit logs are included as Figure 3. SUBSURFACE G4NDITIONS The subsurface conditions at the site ~nrere evaluated by monitoring the fa_n- backhoe test pits at the site and our experience in the site area. Based on the results of our test pit excavations, between 1 and ~ feet of black "Steilacocm" aravel or recessional sandy gravel with variable cobbles and boulders was encountered in the test pits at the site. The recessional soils at depth v~rere in a medium dense condition. (~lo groundwater seepage was obs~rv?d in the test pits excavated at the site. CONCLLtS1011a AND RECOrUIMEl~I©ATtONS GENERAL The site-specific soils at the proposed location of the stormwater pond consist of medium dense sandy gravel with cobbles and boulders. These soils have a high permeability and are suitable for the infiltration of stormv~.~ater. STORM411fATER INFILTrRAT1rJN RATES Based on the soils encountered in our explorations at. the site and the adjacent south area or lot and the lack of any evidence for shallo~nr groundwater, ~,nre conclude that the infltration of storm water is feasible at the site. The deposits of recessional outwash soils in the site area have adequate permeability and storage capacitu to infiltratQ storm ~~iater from the commercial structure and paved surfaces, provided adequate design: construction and maintenance practices are used. Storm water infiltration rates for the site ~Nere determined in accordance with the DOE Stromwater Allanual guidelines and Table 1. °ased on the soils observed in the test prks excavated at the proposed infiltration areas at the site and the adjacent south property, we recommend a maximum design infiltration rate of 20 inches per hour or 3 minutes per inch be used for the infiltration systems. An appropriate factorrf safety should tie applied to tllis value. LIMtTA T IONS ~Ne have prepared this report for the Prairie °laza Company and their project consultants, fcr use in design and constn.rclion of the varioras components of this project. The data and report can be utilized for bidding or estimating purpo5es> but our report, conclusions and recommendations should not be construed as a warrant; of the subsurface conditions, as they may vary both vertically and laterally. If there are changes in the locations or assumptions stated for this project, the conclusions and recommendations presented may not be fully applicable. If design changes are made, we should review the proposed ;,hanges to verify the applicability of our conclusions and recommendations. GEORESOURCES LLC 253 888 8592 05/15/08 O9:18pm P. 003 Prairie f~laza - Yelm May 13, 2GG3 Page 3 Vlfdhin the limitations of scope, schedule and budget, our services have been executed in accordance with generally 2.ccepted practices in this area at the i_ime this repe~Z was prepared. No warranty, express or implied, should be understood. ~ ~ 1Ne appreciate the opportunity to he of senrice to yo~.i or. tl;is project. Please call if you have any questions regarding this submittal, or if tire can provide additional servic:~s. 'Y~~urs very truly, Geof'.esoui ces -~ V ',, -~±~ ,'t~ ~~~'~% ~-~' f ~ ~' ~ Hydro~g .,~U ~+~ S~/~ BRADLEY P. 89GGER~Tr1FF Brad P. Bigyerstaff, LHG Principal ,4ttachments DocID: PrairiePlaza.01 RH GEORESOURCES LLC 253 698 8992 OSI1St03 09:18pm P. 004 SOIL CLASSIFICATION SYSTEM GROUP MAJOR DIVISIONS SYMBOL GROUP NAME .GRAVEL CLEAN GW ~ WELL•GRAOEO GRAVEL. FINE TO COARSE GaAVEL VEL COARSE G RA GRAINED GP POORLY•GRAOEO GRavEL ,SOILS Moro Than 50°,0 of Coarse Fraction GRAVEL GM SILTY GRAVEL ' f Retained• lNES WITH GC CLAYEY GRAVEL on No, 4 Sieve More Than 50°,G SAND CLEAN SANG SW YIELL-GRADED SAND. FIN£ TO COARSE SAND Retained on No. 200 Sieve • SP POORLY•GRAOEO SANG . Male Than 50°,6 o/ Coarse Fraction SANG SM. SILTY SAND S Posses. WITH FINE Sr CLAYEY SAND No. 4 Sieve ~ F1NE SILT AND CLAY ML SILT " GRAINED INORGANIC SOILS - CL CLAY Liquid Limit _ Less Than S0. ORGANIC OL ORGANIC StLT, ORGANtC CLAY SILT ANO CLAY MN SILT OF HIGH PLASTICITY, ELASTIC SILT More Than 50°k • INORGANIC Passes CH CLAY OF NIGH PLASTICITY, FAT CLAY _ No. 200 Sieve liquid Limit ORGANIC OH ORGANIC CLAY, ORGANIC SILT SO or h1oro HIGHLY ORGANIC SOfLS PT PEAT NOTES; 1. Feld classification is based on visual examination al sail in general accordance with ASTNI D24138.90. 2. Soil classification using laboratory tests is based on it AsTM Dz4s7•sa, 3. Descriptions of soil density or consistency are based on interprt:talion of blow count data, tisual appearariea of soils, and/or test data. SOIL PAOfSTURE t.100iFiERS: Dry - Absence of moisture, dusty, dry to the touch Moist - Oemp, but no visible water Vlet • Visible tree water or saturated, usually soil is obtained From below water table ~e~Resources SOIL CLASSIFICATION SYSTEh9 ~iGURE GEOR.ESOURCES LLC 253 638 8992 05/15/03 09:18pm P. ~c747S 'I'i~ST PAT il.~~(;•S PE~/a.RR6~', Pt~A;~A. 1'FLI~~i Pl1CRCF', ~'4~rl1~VT'a-, '~,i~~-:~H~N~T+~N TEST P1T 1 - V~rest portion of infiUration ,rrca i~cFth(fl.) SoilTy~c-___--__ Dcscript.i~n_.__ (1.O - 2.0 Gtil Blaci< si GRAt/1~?L. (tncd dcnsc. mots?) 2.O - 1 l.O GP Prn sandy G%AVEi! gra~~elh; 5,1ND ~~/cobbles & boulders (mcd dense. moist) No Gavin; obscn~ctt To ground~.~atcr ti<:clrage obscrecd TEST PiT 2 -Central infiltration ;area Depth fl_ -_ Sail TyUC _Uescri ~t~_ O.0 - l.~ GM Placl+ si GFZ/~~/F:L (rated dcnsc. moist? 1.5 - 1 l.> GP Brn sand}~ GRAVEL/ gravelly Sr~ND «/ cobbles cX. boulders (recd dcnsc, nroisl) Trace cap-in;; obser~ cd No gronncll~,atcr ,ccpage ohsct-~ ccl 'TEST PlT 3 - Aast infiltration area Dc th fl. _! Soil Type ~Descnntior- ---._ ----------------_-• -- ~.() - 4.0 G7vt Blad< si GRAVEL (r,rcd dcnsc. nroisl) 4.O - 12n GP f3rn sandy CiRAVELi r,ra~ ell` SAND w'/ cobb[cs & boulders (mcd dense. moist) No caving, obsct~-cd No groundrra(cr sccpa~~c obscr7 cd TEST PiT 4 - .Across Road. south in611ration area I)cpth (ft.l Soi f T~ pc ---Descrint ion . - -- _. ----- --- Q.1) - 2.Q GM Plack si (.~Rn~/F'L (mcd dcnsc. rtroist} ---------- ---- 2. ~ - ~.~ GP 13tH borrldctY SANI~i!;RAVEL (mcd dcnsc. moist) ~.O - 1 LS GI' Prn sandy f;RAVIiI~~ L ray Illy S/~tiT~ w/ cobbles ~ boulders (mcd dcnsc- tnoist) No caving; observed No grottndvwatcr s,a;pa,>;c ohscr~;a1