Laserfiche WebLink
i• <br />Drainage Area D <br />There is a minor ephemeral channel that must be diverted around Sediment Pond C. <br />The 10 year peak flow for drainage area D is 8.36 cfs. The refuse pile upper diversion <br />ditch drains into this minor ephemeral channel. The maximum peak flow from this <br />channel is 6.26 cfs presented in Appendix C of Volume 4. The total design flow for this <br />channel is 14.62 cfs (8.36 + 6.26). <br />The flow value for the upper diversion ditch is the flow based on the 10 year event. See <br />Volume IV, Appendix B, ditch reach 4b. <br />Drainage Ditch D -D1 <br />Manning's Equation <br />Flow In a Trapezoidal Channel <br />DEPTH <br />D <br />0.300 <br />FEET <br />WIDTH <br />W <br />10.000 <br />FEET <br />Slope <br />S <br />0.100 <br />EXPRESS AS DECIMAL <br />Mannings "N" <br />N <br />0.040 <br />EXPRESS AS DECIMAL <br />SIDE SLOPE <br />X <br />3.000 <br />SLOPE = X:1 <br />• <br />AREA= (W*D) +(X *DA2)= <br />WETTED PERIMETER= (W) +2 *[((X *D)A2 +DA2)A0.51 <br />R= AREA/WETTED PERIMETER <br />V= (1.49 /N) *(RA.667) *(SA.5)= <br />Q =AXV= <br />Q REQUIRED - Peak Discharge <br />Riprap Sizing - Drainage Ditch D -D1 <br />D50 = Size of Riprap <br />D50 = ((V x SA 17)/7.58))A2 <br />D50 = Diameter in feet <br />V = Velocity <br />S = Slope <br />D50 = 0.197 feet <br />None Required <br />2.367 inches <br />Construct ditch D -D1 a minimum of 2 feel deep to provide for <br />freeboard and lessor ditch slopes. <br />PR -07 EXH -8 -11 <br />3.27 FEET A2 <br />11.90 FEET <br />0.27 <br />4.98 FT /SEC <br />16.28 CFS <br />14.62 CFS <br />2/03 <br />