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Qdn= (0.9)(0.5)(9.G4) = 4.34 CFS <br /> Residence time provided for 4.34 CFS: <br /> 1 sec X 1 min x 1 CF x 2500 ga I = 1.28 minutes <br /> Trcs 4.34 CFS 60 sec 7.48 ga I <br /> The vault inlet has been restricted by an orifice to pass only the oil/water separator design <br /> flow at the head available between the vault inlet pipe and the bypass pipe. An 18-inch <br /> pipe was used as the bypass pipe (the conveyance calculations for the bypass pipe are <br /> located in the Conveyance Calculations section of this report). Tlie available head <br /> between the pipe inverts is 2.15 £eet (588.22 ft - 58G.07 ft). The required orifice <br /> diameter was determined by the following equation: <br /> q�Q� A(4.34) = O.S7 feet - Use 10.�-inch O orifice. <br /> d = � � -� �-- <br /> 0.62n G4.4 h 0.62r G4.4(2.15) <br /> The oil/water separator �vas also cliecked to ensure that larger flows into the separator <br /> would not cause accumulated oil to be tlushed out of the separator. The available head <br /> for both the vault inlet and the bypass inlet were used to ensure the two pipes could handlc <br /> a large storm event. The oil/waier separator was checked against the 25-year storm. <br /> Q35= c I A where c= 0.9; I = 1.42 in/hr, A= 9.64 acres <br /> [See 25-year Conveyance Calculations - CB #1 S] <br /> Q:5 = (0.9)(1.42)(9.64) = 1232 CFS <br /> Top of vault elevation = 589.4G <br /> Head available for vault inlet = 3.39 feet (589.46 ft - 586.07 ft) <br /> H�ad available for bypass inlet = 1.24 feet (589.46 ft - 58522 tt) <br /> The capacity of each inlet was determined by the following equation: <br /> 2 <br /> Q = ��q 64.4(h) . <br /> Qvault — �0.62)��0.�75)2 G4.4(339) = S.SGCFS <br /> STORM DRAINAGE I2EPORT FOR 1NTFtA�VEST-SEAR'Al' - PAGE R <br />