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r . � <br /> ( Srormwnrer Si(e Plan jor Northwerl Animal Care May 19,2002 <br /> 1 <br /> f SECTION V RUNOFF COIVTROL BMP'S <br /> Water Qurlity Desip <br /> IWater quality treatrttent facilities for the project consist of a wetpond and biofiltration swale. <br /> The wetpond is accommodated inside a vault and open pond. 'The dead storage in thc <br /> �, detention/water quality vault exceeds 85 percent of the 6-month storm runoff. The vegetated <br /> ' pond contains 15 percent of the 6-month storm runot�: <br /> ( Runotf Volume (cubic [t.) <br /> Required Proposed <br /> I_ 6-month Storm Runoff 1,724 3,148 <br /> Open water Cell 1,465(85%) 2,880 <br /> � Vegetated Cell 259(15%) 268 <br /> � 'I'he flow into the biofiltration swale is controlled by a lift station. The lift station pump rete is <br /> 40 gallons per minute(0.090 cubic feet per second). Higher flows will exceed the capacity of the <br /> pump, bypass the treatment facilities and flow directly to the public storm drain in 19`h Avenue. <br /> LThe lift station is located downstream of the detention vault. Biofiltration swale details are: <br /> 6-month Storm Flow 0.015 cfs <br /> I 2-year Stortn Flow 0.022 cfs <br /> Swale Design Flow(Pump Flow) 0.090 cfs <br /> ISwale Flow Depth(at 0.090 cfs) <br /> Emergent (U.63%) 0.20 feet(max. allowed 0.50 feet) <br /> IGrassed(2.16%) 0.16 feet(max. allowed 0.33 fcet) <br /> I Flow Control Facility Design <br /> Flow control is accomplished in a detention vault that is combined with the water quality vault. <br /> ,I <br /> The flow control criteria are: <br /> • 2-yeaz developed runoff released at 50 percent of existing condition rate <br /> I • 10-year runoff released at existing condition rate <br /> • 100-year runoff released at existing condition rate <br /> i P��,� <br /> � O <br /> - - ---- ----._—•�__ . <br />