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TABLE 4.6-28 (continued) <br />• Ponding Adjustment Factor <br />Since our spoil areas have such a high infiltration rate and virtually no runoff, <br />we hove determined that all of our spoil areas acT os a ponding effect for the <br />watershed area. An aerial photo map of the area (Exhibit 4.6-{8) is included to show <br />the areas in the central part of The watershed and the upper part of the watershed <br />that act as ponding areas. <br />Acres in the central part of the watershed (ponding area = 205.99 ac) <br />9o Ponding Areo - 205.99 ac X 100% = 21.49'0. <br />- 961.01 ac <br />From Table E-3 by interpolation for a storm frequency of 10 years. <br />Factor = 0.53 + (25.0-21.4) (0.56-0.53) = 0.55. <br />25.0-20.0 <br />Acres in the upper part of the watershed (Ponding area = 57.04 ac) <br />• % Ponding Areo - 57.04 ac. X 100% = 5.9%. <br />- 961.01 ac. <br />From Table E-4 by interpolation for a storm frequency of 10 years <br />Factor = .80 + (6.7-5.9) (0.82-0.80) = 0.81. <br />6.7-5.0 <br />Since we have two conditions existing for Ponding Areas, we will find a weighted <br />overage factor the areas according to acres. <br />Weighted Ponding Factor = (205.99 ac)(0.55)+(57.04 ac)(0.81) 0.61. <br />205.99 + 57.04 ac. <br />Peok Discharge = 80.0 cfs x 0.61 = 48.8 cfs. <br />r1 <br />LJ <br />Revised 7-81 4.6-86 <br />