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<br />Table IO.--Regional flood-frequency equations <br /> <br />Eouation for indicated <br />T-ye~r flood discharge (cfs)!/ <br /> <br />Standard error <br />of estimte <br />(percent) <br /> <br />Estimate of <br />minimlIDl <br />prediction <br />error (percent) <br /> <br />Q1. 25 <br /> <br />( )0.88( ",,)-0. l3 ( )1.02 <br />195 A L/v8 K <br /> <br />11 <br /> <br />30 <br /> <br />Q2 <br /> <br />369(A)0.90(L/IS)-0.19(K)0.65 <br /> <br />11 <br /> <br />30 <br /> <br />Q5 <br /> <br />621(A)0.93(L/IS)-0.23(K)0.42 <br /> <br />10 <br /> <br />29 <br /> <br />n <br />"10 <br /> <br />776(A)0.95(L/IS)-0.25(K)0.35 <br /> <br />10 <br /> <br />29 <br /> <br />Q25 <br /> <br />953(A)0.98(L/IS)-0.27(K)0.32 <br /> <br />10 <br /> <br />29 <br /> <br />Q50 <br /> <br />1,067(A)1.00(L/IS)-0.28(K)0.32 <br /> <br />10 <br /> <br />29 <br /> <br />( )1.02( / ",,)-0.29( )0.33 <br />Q100 = 1,172 A L ,8 K <br /> <br />10 <br /> <br />29 <br /> <br />where: <br /> <br />Q = discharge in cubic feet per second (cfs) <br /> <br />A drainage area in square miles (sQ mi) <br /> <br />L length in miles (mi) <br /> <br />S slope in feet per mile (ft/mi) <br /> <br />K = coefficient of imperviousness <br /> <br />!! Cubic feet per second x 0.0283168 = cubic meters per second. <br /> <br />-44- <br />