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will be adequate. The normal depth of flow will be 1.66 feet with a flow <br />• velocity of 4.87 fps; therefore, subcritical flow will exist and riprap is <br />not required. A ditch section three (3) feet deep is proposed which will <br />allow 1.34 feet of freeboard, which is conservative. Again using the <br />Dodson and Associates, Inc.'s computer software, a rating curve is <br />computed for the proposed ditch section at various depths of flow and flow <br />rates. <br />Trapezoidal Channel Analysis <br />Rating Curve Computation <br />Channel Bottom Slope (feet per foot) 0.01 <br />14anning' s Roughness Coefficient (n-value) 0.025 <br />Channel Side Slope - Left Side (horizontal/vertical) 2 <br />Channel Side Slope - Right Side (horizontal/vertical) 2 <br />Channel Bottom Width (feet) 0.0001 <br />Results <br />• <br />Cepth Flow Fate Velocity Froude Velocity Energy Flow Area Top Width <br />(ft) (cfs) (fps) dumber Ilead (ft)( Head (ft) (sq ft) (ft) <br />0.25 0.2 1.38 0.688 0.03 0.28 0.13 1.00 <br />0.50 1.1 2.19 0.772 0.07 0.57 0.50 2.00 <br />0.75 3.2 2.81 0.826 0.13 0.88 1.13 3.00 <br />1.00 7.0 3.48 0.866 0.19 1.19 2.00 4.00 <br />1.25 12.6 4.03 0.899 0.25 1.50 3.13 5.00 <br />1.50 20.5 4.55 0.927 0.32 1.82 4.50 6.00 <br />1.66 .26.9 4.87 0.943 0.31 2.03 5.51 6.64 <br />1.75 30.9 5.05 0.951 0.40 2.15 G.13 7.00 <br />2.00 44.1 5.52 0.972 0.47 2.47 8.00 8.00 <br />2.25 60.4 5.97 0.992 0.55 2.80 10.13 9.00 <br />2.50 80.0 6.40 1.009 0.64 3.14 12.50 10.00 <br />2.75 103.2 6.82 1.025 0.72 3.47 15.13 11.00 <br />3.00 130.2 7.23 1.040 0.81 3.81 18.00 12.00 <br />u <br />A-3 02/13/87 <br />