Laserfiche WebLink
Riprap Size Calculation Ditch 1 <br />• <br />Use formula <br />d50 = 12 (118 QS13/6 r ~ 2/5 <br />P <br />d50 = diameter in inches of median riprap <br />Q = design peak flow in cfs <br />S = Slope of channel/ditch <br />r = Hydraulic radius <br />P = Wetted perimeter <br />Q = 872 cfs <br />S = 11.5%; 2.8% <br />r = 1.51; 1.97 <br />• P = 21.71; 28.34 <br />d50 = 64; 19 <br />Riprap designation VH; H <br />Bedding Material Type II; II <br />Bedding Material Thickness 8 inches; 8 inches <br />Segment 1 Type VH riprap with 8 inches of Type II bedding <br />material or equivalent <br />Segment 2 Type H riprap with 8 inches of Type II bedding <br />material or equivalent <br />• <br />-5- <br />