6003 23RD DR W 2018-01-01 MF Import

i w��i��c/� � Determ:riing Number of '��►�� =�Q� Cartridges for Systems STORMWATER Downstream of Detention SOLUTIONS u+c. I I Determininq Number of Cartridaes for StormFilter Svstems CONTECH Stormwater Solutions Inc. Engineer: KET Blue Cells = Input � Date 111912006 Black Cells= Calculation Site Information I Project Name Seaway Lot 36 Project State Washington Project Location Everett � Drainage Area,Ad 0.38 ac Impervious Area,Ai 0.25 ac Pervious Area,Ap 0.13 % Impervious 66% � Runoff Coefficient, Rc 0.64 Upstream Detention System Peak release rate from det�ntion, Qreleasepeak 0.240 cfs ITreatment release rete from detention, Qreleasetrea� 0.002 cfs Detention pretreatment credit 50% (from rcmoval efficiency�:alcs) ( Mass lo�ding calculations Me�n Annual Rainfall, P 37 in Agency required "/a removal 80% I Percent Runoff Capture 90% Mean Annual Runoff,Vi 29,494 n' Event Mean Concentration of Pollutant, EMC 100 mg/I I Annual Mass Load, M,o„i 184.02 Ibs humber of cartridges -mass loading Mass removed by pretreatment system, Mo,o 92.01 Ibs I Mass load to flters after pretreatment, MPasz� 92•01 Ibs Estimate the required filter efficiency, E,,i,e� 0.60 Mass to be captured by filters, Mnn�, 55.20 Ibs IAllowable Cartridge Flow rate, Q�rt 7.5 gpm Check that Q�,n can meet Er,i�� OK Number of CaRridges required, Nma„ Z ITreatment Capacity 0.03 cfs Determine Critical Sizing Value Number of Cartridges using Q��case veab Nno,v � Method to Use: MASS-LOADING SUMMARY Trealment Flow Rate, cfs 0.03 Cartridge Flow Rate, gpm �•5 � Number of Cartridges Z i � 12021-8 NE Airport Way 002006 CONTECH Stormwater Solutions Portland, OR 97220 � of 1 Icontechstormwater.com Phone: 800-548-4667 Fax: 503-258-3190