Loading...
Drainage Calcs 001Olympic Engineering TBM - Velm 6162005 p06001 DRAINAGE CALCULATIONS The following calculations were based on the requirements contained in the WSDOE 1992 Stormwater Management Manual and the llrainage Design and Erosion Control Manual (DDECM) £or Thurston County, 1994 Edition. DESIGN AND BASIN INFORMATION SUMMARY: Basin ID A Total Impervious Pavement 0.29 0.29 Impervious Roo£Area 0.09 0.09 Disturbed Pervious 0.10 0.10 Total 0.48 0.48 Soil Classification: SCS Soil Classification: Spanaway Gravelly Sandy Loam Hydrologic Group: A Design Infiltration Rate: 20"/hr WATER QUALITY CALCULATIONS Minimum Stormwater Treatment Area Required: Using an impervious surface area of 0.35 ac and DDECM design value of 2,000 sf/ac results in a required filter strip area of 2,000 sf/ac x (0.38 ac) = 760 sf Stormwater Treatment Area Provided: 190' long by ld wide filter strip = 1,900 sf Total Treatment Area Provided = 1,900 sf > 760 sf .~. OK 1of2 Olympic Engineering TBM - Velm 6/6/2005 #05001 WATER QUANTITY CALCULATIONS *See attached StormShed software output 190' long x 2' wide x B deep infiltration gallery Void ratio = 0.30 (190')(2)(2)(0.3) = 228 cf Total Storage Volume Provided =228 of Active Live Volume = 131 at Elev. = 345.65' per StormShed modeling 228 cf > 131 cf .'. OK 4S Hour Drawdown: (190' x 2')(20 io/hr)(1'/12'x(48 houre) = 3Q A00 cf> 131 cf .: OK 2of2 Olympic Engineering TBM - Velm StortnBhed 1105001 6/612005 RLPCOMPUTE [Infiltration Level Pool] SUMMARY 100 yr MatchQ=PeakO= 0.4077 cfs Peak Ou[ O: 0.3801 cfs -Peak Stg: 345.65 ff - Active Vol: 131.27 cf Summary Report of all RLPooI Data Project Precips [2 yr] 2.00 in [5 yr] 2.50 in [10 yr] 3.00 in [100 yr] 4.00 in [6 mo] 1.28 in BASLIST2 [Basin A] Using [TYPEIA] As [100 yr] LSTEND BasinlD Peak O Peak T Event ------- (cfs) (hrs) Basin A O.40rr 8.00 BASLIST [rYPE1A] AS [100 yr] DETAILEC [Basin A] LSTEND Drainage Area: Basin A Hyd Method: SCS Unit Hyd Peak Factor: 484.00 Storm Dur 24.00 hrs Area CN Pervious 0.1000 ac 85.00 Impervious 0.3800 ac 98.00 Total 0.4800 ac Supporting Data: Pervious CN Data: Landscaping 85.00 Impervious CN Data: Pavement 98.00 Building 98.00 Pervious TC Data: Flow type: Description: Fized None Entered Impervious TC Data: Flow type: Description: Shallow Pavement Peak Vol Area Melhod Raintype (ac-ft) ac ILOSs 0.1393 0.48 SCS/SCS TVPEIA 100 yr Loss Method: SCS CN Number SCS Abs: 0.20 TC 0.02 hrs 0.01 hrs 0.1000 ac 0.2900 ac 0.0900 ac Lenglh: Slope: Coeff: Travel Time 0.00 ft 0.00 % 1.0000 1.00 min Length: Slope: Coeff: Travel Time 75.00 ft 0.50 % 27.0000 0.87 min HYDLIST SUMMARY [100 yr out] LSTEND Hyd ID Peak Q Peak T ------- (cfs) (hrs) 100 yrout Peak Vol Cont Area (ac-ft) (ac) 0.38 8.00 0.1388 04800 1 oft Olympic Engineering TBM - Velm StoimSheG #05001 6I6I2005 STORLIST [Infltration Gallery] LSTEND Node ID: Infiltration Gallery Desc: Infiltration Gallery Start EI: 344.5000 ft Max EI: 346.5000 fl Conirib Basin: Contrib Hyd: Length Width Void Ratio 190.0000 ft 2.0000 ft 30.00 DISCHLIST [Infiltration Gallery] LSTEND Control Structure ID: Infiltration Gallery -Infiltration control structure Descrip: Infiltration Gallery Start EI Max EI Increment 344.5000 ft 346.5000 H 0.10 Infil: 20.00 in/hr Multiplier: 1.00 z oft Y U N O I ? N 0 O n ~ ~_ n O ~ ~ I O ~ ~ 10 ! 3 w ___~ ~ ~ ~~ z ~~~~~ N ;~ ~~ ~~ (1~ r,( --~~70 0, w } N oc~~ ~ z J ~' ~oQ ©Q" ~ ,.~ Q ~ Q ~ D U O , ~a u d w w ~ >- ' > mU raw ¢ w ~ Q - o- ~ w ~ ~ w U - w ~ T O } ", ~ O w ~ ~ r U1 H OOO N 0.. O o~ m m ~o J ~,~ ~m ~ o: -~ w , z _, z o U ~ ~ Iii ~ ~ U Q w ~ ~ ~ ~ ~ U ut C z ~ Q U 0] w ~ 5_ ~ N N co W ~ ~ ~ ~,, Q d W T LL ~ ~ J m z r ~o w ~ o u o ~ ~ ~ z m O 3 K o ~ o o Z _~ V W N W J J Q J f7 ~ Q W ? Y Q , D F a W H J LL O 00