|
i�
<br />,, -1l
<br />II cow� x��H wc sxir�c- ��STORMWATE��
<br />� w�n o�r xr nc.11
<br />i�--' —__ _— _"—" _—_
<br />Determining Number of Certridges for System� Downstream of Detention
<br />Project: Lillys Court Dato: January 18, 2006
<br />Locallon; SnohomishCounry SMIEngr.: 1HR
<br />Step 1 Datarmine meximum release reto from detention
<br />Q,.,�„�,,. (cls) OJ85
<br />Stap 2 Deturmine VooVnent raleese rate tram detentbn
<br />Q,si....vea (cfs) 0.01
<br />Step 3 input tha percontngo of poll��ent removel requlrM
<br />Agency'K 80%
<br />Stop 4 Celculate preVeaVnent removel elficien�y using FHWn; �ethod
<br />Volume of setUing basin, Vb Qt') 3pq
<br />RunoltVolumc,Vr(ft') � 3082
<br />Slep 5
<br />Slep fi
<br />S[ep 7
<br />5[ep B
<br />Ralio af Vb/Vr
<br />Depth ol water in �asin, H Qp
<br />Pretreatment Elliciency, Ep,e
<br />(not ;o exceetl 50%, see attacheU graph)
<br />Calculate the ennua� mess loetl
<br />Mean Annual Rainfall, P (in)
<br />Srte Arca, A (ucres)
<br />hnpervious Area (acres)
<br />Pcrcentlmpervious(%)
<br />Composite Runolf Coeflicient, C
<br />Percent Funofl CapWre
<br />Mean Mnual Runolf,V, (ft')
<br />Event Mcan Cancentmtion ol POIWtant, EMC (mg/q
<br />Annual Mass Loatl, M,o,,, Qbs)
<br />Celculete the number of cartridges on a massloeding besis
<br />Mass removed by pretreannent system, MP,o pbs)
<br />Mass load to Il:lers afler pretrcatment, M p,,,� (Ibs)
<br />Estimate the required lilter elliciency, E�„�,
<br />Mass to be caplured by filters, MrM, (IUs)
<br />A!lowable Cart�itlge Flow rate, Q�,,,(gpm)
<br />Check that Q�,,, can meet E��„
<br />Mass loatl per cartritlge, M�� (16�)
<br />Numb^r o� Cartridges required, Nm.�,
<br />Treatment Capaciry (cfs)
<br />Getormine CrRlcal Slzing Vnluo
<br />Numbcr of Cartridges using Q,,,�,,, �.�„• h'��,
<br />Chose Method Wtth Most NumOer of Carlrldges
<br />MethoO to Use:
<br />t Flow Rate
<br />Flow Rate
<br />r— 0.30
<br />�
<br />28'Y
<br />38 �
<br />0.62
<br />0.33
<br />53 �
<br />0.53
<br />90%
<br />40,720
<br />100
<br />� 254.05
<br />71.13
<br />182.92
<br />72%
<br />132.11
<br />7.5
<br />OIS
<br />36
<br />1 ' �
<br />0.07
<br />��
<br />MA55-LOADING
<br />7.5
<br />4
<br />Page 1 I
<br />r '.
<br />
|