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. PEAK FLOW CALCULATIONS <br />The following peak flow calculations were compiled with the computer program STORM <br />version 6.21. Details of the run -off calculations are shown on the following pages. <br />• <br />DEPTH D <br />10 -YR <br />25 -YR <br />10.000 <br />24 HR <br />24 HR <br />Mannings "N" N <br />Event <br />Event <br />Pond B Drainage <br />17.05 <br />22.63 <br />Pond C Drainage <br />30.62 <br />40.19 <br />Drainage Area D <br />8.36 <br />- - -- <br />Drainage Area E <br />1.79 <br />- - -- <br />Flow calculations for the site ditches and culverts are <br />Sediment Pond B <br />presented in following sections of this exhibit. <br />Riprap Sizing - Across top of Embankment <br />Spillway Pond B <br />D50 = Size of Riprap <br />D50 = ((V X S ^.17)/7.58)) -2 <br />Pond B Emergency Spillway <br />D50 = Diameter in feel <br />Manning's Equation <br />S = Slope <br />Flow In a Trapezoidal Channel <br />• <br />DEPTH D <br />0.500 <br />WIDTH W <br />10.000 <br />Slope S <br />0.020 <br />Mannings "N" N <br />0.030 <br />SIDE SLOPE X <br />2.000 <br />AREA= (W*D) +(X *D <br />WETTED PERIMETER= (W) +2 *[((X *D) +D 2 ) 1/2 1 <br />R= AREA/WETTED PERIMETER <br />V= (1.49 /N) *(R 2 ' 3 ) *( " 2 )= <br />Q =AXV= <br />Q REQUIRED - Peak Discharge <br />Sediment Pond B <br />Riprap Sizing - Across top of Embankment <br />D50 = Size of Riprap <br />D50 = ((V X S ^.17)/7.58)) -2 <br />D50 = Diameter in feel <br />V = Velocity <br />S = Slope <br />D50 = 0.08 feet <br />PR -07 EXH -8 -6 <br />FEET <br />FEET <br />EXPRESS AS DECIMAL <br />EXPRESS AS DECIMAL <br />SLOPE = X:1 <br />5.50 Feet <br />12.24 Feet <br />0.45 <br />4.12 Ft /Sec <br />22.67 CFS <br />22.63 CFS <br />0.94 inches None Required <br />2/03 <br />