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<br />Table G-3 (Continued) <br />• <br />CHANNEL DESIGN <br />Channels below the impoundment have been designed to withstand the worst case <br />condition (i.e. passing 7.5 cfs) <br />1. Channels Below Spillways <br />Worst Case: Below spillway channel <br />Q25 = 7.5 cfs S = 0.07 <br />Minimum Channel Protection = 6 in. rip rap <br />n = 0.031*, Z = 3:1, Vp = 7.9*fps <br />*n & V (Ref. U.S. Dept, of Cortmerce, Bureau of Public Roads, Design of <br />Roadsi~e Channels, Hydraulic Series No. 4) <br />A Minimum = 7.5 cfs_ 0.95 ft2 <br />7.9 fps <br />Try Triangular Swale: d = 1' <br />• A = zd2 = (3)(1)2 = 3 ft2 OK <br />Check Velocity <br />V = 1.031R2/3S1/2 R = A/P A = 2 ft2 <br />P = 2d 1+32 <br />= 6.33 <br />R = 0.474 <br />V = 7.73 fps OK <br />. Channels will use minimum 6" rip rap on gravel bed <br />d=1' <br />r 1 <br />U <br />G-10 <br />