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Page 6b of 9 <br />Ditch 7 (Upper Segment) <br />Manning's Equation <br />Flow In a Trapezoidal Channel <br />Depth <br />D <br />0.27 <br />Feet <br />Width <br />W <br />5 <br />Feet <br />Slope <br />S <br />0.40 <br />Express as Decimal <br />Mannings "N" <br />N <br />0.035 <br />Express as Decimal <br />Side Slope <br />X <br />2 <br />Slope = X:1 <br />AREA= (W *D) +(X *D "2)= <br />WETTED PERIMETER= (W) +2 *[((X *D)- 2 +D ^2) ^0.5] <br />R= AREAIWETTED PERIMETER <br />V= (1.49/N) *(R ".667) *(S ^.5 )= <br />Q =AXV= <br />Q REQUIRED - Peak Discharge* <br />`volume 6A, Tab "Reclaimed Configuration", Point 8 +C <br />�Riprap Sizing - Ditch D -3 <br />D50 = Size of Riprap <br />D50 = ((V X S ^.17)/7.58)) ^2 <br />D50 = Diameter in feet <br />V = Velocity <br />S = Slope <br />1.50 FEET ^2 <br />6.21 FEET <br />0.24 <br />10.43 FT /SEC <br />15.60 CFS <br />15.30 CFS <br />D50 = 1.39 feet 17 inches Use 18" Rock <br />Vol. 6A TR -54 08/12 <br />