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<br />DRAINAGE CRITERIA MANUAL <br /> <br />RUN OFF <br /> <br />Step 7. Add the Routed Flow in Column 3 to the total Local Inflow in <br />Column 4 for Reach A-B, round off to nearest three significant <br />figures or a whole number and enter in the Total Outflow Column <br />5 for Reach A-B. This becomes then the inflow hydrograph for <br />Reach B-C. <br /> <br />. <br /> <br />Step 8. Repeat Step 1 for Reach B-C. <br /> <br />3 <br />Qp = 295 ft /s <br /> <br />3/4 Qp = 221 ft3/s <br /> <br />Step 9. Repeat Step 2 for Reach B-C. <br /> <br />(Qn)/(S1b8/3) = (221 x 0.45)/((.008)1(20)8/3) = .0377 <br /> <br />y/b = 0.10 <br /> <br />y = (0.10 x 20) = 2.0 ft <br /> <br />. <br /> <br />A = (20 x 2.0) + 3(2.0)2 = 52 ft2 <br /> <br />v = Q/A = 221/52 = 4.25 ft/s <br /> <br />T = (2 x 3 x 2.0) + 20 = 32 ft <br /> <br />F = V/V A g/T'= 4.25/ -V (52)(32.2)/32' = 0.59<0.95 <br /> <br />Use V = 4.25 ft/s since it results in the natural channel <br />Froude Number of less than 0.95 <br /> <br />Step 10. Repeat Step 3 for Reach B-c <br /> <br />C1 = V/(V+1.7) = 4.25/5.95 = 0.71 <br /> <br />K = L/(3600V) = 3000/(3600 x 4.25) = 0.20 <br /> <br />. <br /> <br />5~1-84 <br />