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Job Number: 93-419-26 <br />Calculated by: T. Fisher <br />Checked by: <br />Project: Everett Clinic <br />FII@: F:\93\419�DOCS\BYPAS°.W01 <br />Date: 04-Nov-93 <br />Date: <br />CALULATE THE WEIGHTED SCS CURVE NUMBERS FOR THE BYPASS <br />POSTDEVELOPED CONDITIONS AREA Cn� <br />-grass 0•09 86 <br />-pavement, buildings �•� � 98 <br />T01,1L = 020 Acres <br />WEIGHTED AVERAGE Cn VALUES: <br />•Postdeveloped conditions <br />PERVIOUS IMPERVIOUS <br />86.0 98•� <br />•Note: Hydrologic soil group'C' was used as the SCS <br />soils map indicates Aldenvood (AgC) soils. <br />CALCULATE THE TIME OF CONCENTRATION <br />24 hour isopluvials: <br />2-year (P2) _ <br />Sheet flow: <br />Conc, flow: <br />1.55 inches/day rei. KCSWDM 3.5.1-8 <br />Tt = [0.42•(Ns*L) ^ .8j/[(P2 ^ 0.5)"(So ^ 0.4)J <br />Tt = L/[60`Ks"(So ^ 0.5)] <br />Postdeveloaed conditions <br />Segmerrt Status Length <br />(��) <br />BYPt-BYP2 pavement 53 <br />(conc.) <br />Ns <br />0,011 <br />Ks So Tt <br />(96) (m!n) <br />NA 5.0% 0.7 <br />Total = 0.7 min <br />SUMMARY OF INPUT DATA FOR KCSWDM'S ITYD PROGRAM <br />Postdeveloped: <br />qper Cn Almp Cn <br />(Ac) (Ac) <br />0.09 86.0 0.11 98•� <br />TC P2 <br />(min) (in) <br />0.7 1.55 <br />