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April 18 2003 Worksheet No. 3 of 3 <br /> CROSS-SLOPE TERM �ESIGO ' , <br /> CALCULATION OF CROSS-SLOPE BERM CAPACITY <br /> Procedure: Calculate the full flow capacity in the cross-slope berm using Manning's Equation. <br /> Full flow capacity(Qf)= peak flow in cross-slope berm <br /> Full Flow Capacity(Qf): <br /> Manning's Equation: Qf=VA <br /> Qf= Flow (ft3/sec) <br /> V= Velocity(ft/sec) <br /> A= Cross-sectional Area in Flow (ft) <br /> V = 1.486 x R^.667 x S^.5 <br /> n <br /> R = Hydraulic Radius (ft) <br /> S = Slope (Decimal) <br /> n = Manning's Roughness Coefficient <br /> R =A/P <br /> P = Wetted Perimeter <br /> From Design on Previous Sheet: <br /> A= .5(3d + d)(d)=2d2 <br /> P = (9d2 + d2).s+ (d2 + d2)_5= 4.58d <br /> Assume d = 1.0 ft <br /> A= 2 ft2 <br /> P = 4.58 ft <br /> R = A/P = 0.44 ft <br /> S = 0.008 (Anticipated worst-case slope) <br /> n = 0.025 (Source: GERM, Appendix 19.A, "Natural Channel, Good Condition") <br /> V __ 1.486 x (0.66".667)x (0.008".5) = 3.06 ft/sec <br /> 0.025 <br /> Qf= V*A= 6.12 cfs <br /> This design provides a factor of safety of 3.0 (F = 6.12/2.04) <br /> NA1North County\NCDrainDesign.xls <br /> Sheet: DrainageDesign Printed: 6/18/03 <br />