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• l Two ditch designs are proposed for each the east and west ditches. <br />Based on the critical slope calculations for each ditch, a ditch section <br />will be constructed with riprap or without riprap. depending on whether <br />the ditch's slope is steeper or flatter than critical slope. Each ditch <br />will have a minimum of one foot of freeboard included in the total <br />depth. This will allow the ditch to be field-located as close as <br />practical to the proposed disturbance area but still control all runoff <br />and direct the flow to Pond 005 (see Exhibit 13-4). <br />Following is a summary of "Alternative A" and "Alternative B" ditch <br />design to be used for East and West Ditch. <br />Ditch Factor <br />North Ditch West Ditch <br />q 10.5 cfs 1.0 cfs <br />Z 2:1 2:1 <br />Shape V-ditch V-ditch <br />~,~ "Alternate A" <br />n (without riprap) 0.025 0.025 <br />do 1.11 ft. 0.43 ft. <br />Sc 1.3% 1.8% <br />Yc 4.23 fps 2.65 fps <br />"Alternative B" <br />n (with riprap) 0.04 0.04 <br />Based on the above results, the East Ditch will be constructed with the <br />following minimum dimensions. <br />"Alternate A" (without riprap): <br />Minimum depth = 3.0 ft. <br />• Side Slopes 2:1 <br />Slope = 0% to 1.3% <br />Maximum Velocity = 4.23 fps <br />q = 10.5 cfs <br />• Manning's N = 0.025 <br />Shape V-ditch <br />12 <br />