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Length (L) :Can be entered by the user. If the user selects an area from the screen, <br />the length is not calculated since the Gross Erosion is directly calculated. <br />Topographical Factor (Ls) :Will be calculated from Length (L) and the Slope (S), <br />only when these values are entered by the user directly, as against calculated <br />by the program from the screen. In the second case, the value of Ls is calculated <br />for individual grids and not for the entire area. <br />Ls = (L/72.6)^m * ((430*S^2 + 30*S + 0.43)/(6.613)) <br />where L and S are defined above and <br />m = 0.5 if S=>5%; = 0.3 if S<= 3% ; = 0.4 otherwise. <br />Gross Erosion, E (tons/acre/year) :Calculated from the above defined parameters <br />for each area defined. If the user selects an area from screen, E is calculated <br />in each grid and the cumulative value is calculated. <br />E = R * K * Ls * C * P ,where all the parameters are as defined above <br />Volume Calculations <br />Required User Input <br />Sediment Delivery Ratio (DR) :Default = 0.37 <br />Time Period,T (years) :Time of analysis; typically the time of the storm event <br />Density of the sediment (D) :The post-deposit density of the sediment <br />Runoff (I) :Calculated from some other routine like Curve Number and Runoff <br />Total Erosion (E, tons/year) =Sum of (E * Area) for all the areas. <br />Total Yield (Y, tons/year) = E * DR <br />Sediment volume per year (Vs) = Y /Density <br />Attachment 2.05.3(3)-20-12 <br />