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Table TR 91-31-2 (Cont.) <br />• Area X11 Fill <br />North Side Ditch Design <br />Assune: <br />Ditch :Jidth = b = 6 ft Slope = 35'0 <br />Side Slopes = Z = 1:1 Area = ~bd zd`] <br />Rip-Rap D50 = 1.0 ft R = Hyd. Radius = A <br />b+2d /Z` +1 <br />Q = AV = 1.49 R2/3 Sl/2 A <br />(J <br />N = 0.0395 (050)1/6 = G.G395 (1.0)1/6 = 0.040 <br />• Q = 4.6. 1.49 [ 6d~ (1)d2 ] 2/3 [0.35] '~ ` [_d d`] <br />O.U-.O 6 + 2d ~ <br />Calculate Q assuning flov+ depth = d = 0. i4 ft <br />Q = 37.250 O.S6C 2/3 [0.35 1/2 [O.S6~~~ = 5.0 cfs <br />Cb.,.'. b~ <br />Calcualted Q = 5.0 cfs > Req'd Q = 4.6 cfs <br />Velocity = Q/A = 5.0/ [6(0.14) + 1(O.i4)2]= 5.S fps <br />Check riprap size <br />z <br />D50 = " (S) 0.17 l 2 =r(5.£l)(0.35)0.17 ~2 =r;}.E:21 = 0.376 ft <br />(SG-1)G.G6(5.G) L (Z.ti-1)U.bu (S.S~ Li.9G4 J <br />• Assur..ed D50 = 1.0 ft so design D60 is adequate. <br />Ex. 29-19 <br />