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Volume capacity for the as-built channel at the design flow depth is less than <br /> 7910 CFS (100 YR - 24 HR event), try d = 10.5 <br /> d = 10.5 FT <br /> A = y2(10.5)2(2.03) _ %2(10.5)2(2.84) +'(10.5)(21.0) <br /> A = 488.96 FT2 <br /> R = A/W P = 6.40 FT <br /> V = 1.486/0.04 (6.15)2/3(0.0179)Y2 <br /> V = 16.64 FPS <br /> Q = VA = (16.64)(488.96) = 8136 CFS <br /> The as-built channel flowline will be near 10.5 ft. Determine superelevation on <br /> bends (200' radius) to see if rip-rap height is O.K. <br /> Superelevation = oY = CV2W/gr <br /> oY = (1.0)(16.64)2(72.14)/(32.2)(200) <br /> oY = 3.1 FT <br /> Compare flowline height on curves with as-built rip-rap height. <br /> d + nY = 10.5 + 3.1 = 13.6FT <br /> O.K. <br /> As-Built Rip-Rap Sizing <br /> Using as-built parameters calculate D50 rip-rap size. <br /> Tractive Force on Channel Bottom <br /> To = RS <br /> 11b = (62.4)(6.4)(0.0178) = 7.11 PSF <br /> TO on 2.84 H: 1 V Side Slopes <br /> 1 = To 0 - Sin20/Sin20)0.5 <br /> `r'l = 7.110 - 0.11/0.413)0.5 = 6.09 PSF <br /> DS0 (Straight Section) _ 'rl/0.0Ws -% ) <br /> = 6.09/0.04 (165 - 62.4) <br />