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Pond Sediment Volume Calculation based on Universal Soil Loss Equation (SurvCAD) <br />Input Data <br />Landuse Area Rainfall Erod- Length Slope Ls Cf Pf <br />(ft ^2) Factor ability (ft) (%) <br />Pasture 3153395.5 50.0 0.37 1482.0 5.0 2.05 0.04 1.00 <br />Runoff = 0.350 inch. <br />Sediment Density = 175.000 <br />Time = 3.0 years <br />Drainage Ratio = 0.84 <br />Total Area = 72.392 acres <br />Gross Erosion = 109.983 tons /yr. <br />Total Yield = 92.385 tons /yr. <br />Runoff Volume = 2.110 acre -ft <br />Sediment Volume = 0.073 acre -ft (3 -year total) <br />Total Volume = 2.183 acre -ft <br />* The Cf factor is determined from the chart on the following page, shown in Design Hydrology <br />and Sedimentology for Small Catchments by Haan, Barfield and Hayes. Based on an <br />approximate ground cover of 70% for permanent pasture, a Cf factor of 0.04 was used, which is <br />conservative. <br />The pond volume below the primary spillway will be comprised of two design needs: <br />1) 3 year sediment delivery of 0.1 acre -ft, as based on the calculations above. <br />This is a total volume of 0.1 acre -ft. <br />As seen in the stage storage relationship, the pond has 3.7 acre -ft of storage at (5555') the <br />primary spillway. Detention time of 24 hours is shown in the SEDCAD outputs, which are at the <br />end of this section. <br />REVISED AUGUST 2009 Attachment 2.05.3(3) -6 -5 <br />