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• West Portal ~lvert Data <br />C21 through C25 <br />Oontributing Discharge Minimum <br />Drainage Watershed Slope per Inch 10YR-24HR Culvert <br />Culvert Area Slope Adjust. of Runoff Runoff Peak Diameter <br />No. (Acres) (N (Ft/Ft) Factor (cfs/inch) (Inch) (cfs) (inches) <br />21(1) 31.3 75 0.400 1.20 36.0 0.96 41.5 36 <br />22(1) (same as above) <br />23(2) 52.5 75 0.400 1.20 55.0 0.96 63.4 (see <br /> <br />24(2) culvert <br /> 33.3 75 0.400 1.20 40.0 0.96 46.1 analysis <br /> <br />(2) for pipes <br />25 (total of above) 109.5 23,24&25) <br />(1) Culvert diameter determined using "Culvert Sizing Norograph" , Table 22 using <br /> 1-1/2 ft of head on pipe; ~/D = 1.5. <br />(2) Culvert sizing determined using Hazen-Williams formula for pipe flow below. <br />• West Portal Area <br />Culvert Analysis <br />for Pipes 23, 24 and 25 <br />The west portal pipes no. 23, 24 and 25 bypass runoff from the undisturbed <br />drainage area south of the west portal industrial buildings. These pipes are on a fairly <br />steep slope and due to the length need to be analyzed under pipe flow conditions using <br />Hazen-Williams formula. The following analysis determines the maximun flow for pipe no. <br />25, the collector pipe for pipes nos. 23 and 24. <br />Hazen Williams2F$~nula 0.54 <br />0.442 d c (P - P / L) <br />c = 110 (pipelcvns~ant) <br />d = pipe diameter in inches = 42" <br />P =inlet pressure (psig) = 7.3 psi <br />P1 = outlet pressure (psig) = 0 psi <br />L2= pipe length (ft) = 230 ft <br />Q = flow in gpn <br />~nax = 0.442 (42)2.63 (110) (7.3-0/230)0'54 <br />~nax = 140,224 gpn or/ 312.4 cfs <br />. The maximum flea which pipe 25 will handle is 312.4 cfs which is more than the <br />required 109.5 cfs. <br />Revised 3-19-87 <br />