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� CITY OF EVERET:!' L�RAINAGE CALCULATIliNS (less than 5 acres) 09-Jan-92 <br /> DICK JOHNSON 19TH AVENUE PROPERTY, iSP. No. 2697 11:23 AM <br /> _��________�______________�_______"___________________=________________ <br /> DETENTION PI?E SIZE <br /> _��=====a�====__�_____ * <br /> Assune a i9etn pipearch 35.0 x 24.0 (width and heiqht) <br /> Cross section area = 4.4 sf <br /> Usable vvl. of Type II MH 60.0 inch dia cf <br /> Usable vnl. of 2.0 Type II MH 54.0 inch dia 63.6 cf <br /> Usable vol. of inch pipe: ft long = cf <br /> Usable vol. of 36.0 inch pipe: ft long = cf <br /> Required pipe �•olume = 384.1 cubic feet <br /> Required pipe lenqth = 87.3 linear feet <br /> Length of pipe used = 88.o ft. Vol. provided: 450.8 cf <br /> Minimum grade elevations: <br /> Top D/S detn CB = 567.53 with 1.75 ft Overflow clearance <br /> Top D/S detn CB = 567.33 with 2.0 ft cover <br /> Top U/S detn CB = 567.78 with 2.0 ft covpr <br /> Min Grnd surf. elev = 566.28 (over inlet: 0.5 ft above oF) <br /> inv elev at U/S end = 563.78 <br /> Max water aurface el = 565.78 <br /> Invert elevation = 563.33 <br /> outfall pipe d/s inv = 563.16 pipe: 0.50� slope; 35 ft long <br /> Outfall swale d/s inv. 563.16 swale: 0.50� slope; ft lonq <br /> � CALCULATION OF OUTLET SIZE <br /> �aasmm�aasaa=e-ae�e-�m=e-- <br /> For nultiple ( 1.0 ) orifices, flow / orifice = 0.283 <br /> SIZING ORIFICE FOR RESTRICTOR <br /> 23T�SSC3S�is9S5�6C����T��������� <br /> Orif. E1ev. H, ft a, sf __________d,ft,________d_inches <br /> ------------------------------ ---------- � <br /> 563.33 2.44 0.036 0.22 2 - 5/8 <br /> ----------------------------------------------------------------------- <br /> area, a = Qdo / ( .6z x (2 x g x h)**.5) 4 = 32.2 <br /> orifice diameter, d = ( 4/pi x a)**.5 <br /> � <br /> I <br /> i� <br /> i <br />