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estimates. It should be pointed out again that using a check dam <br />as though it was a silt fence is only an approximation for <br />estimating trap efficiency. The actual silt fence program from <br />SEDCAD+ will not be available for another two years. <br />Particle Size Distribution The particle size distribution for <br />this sedimentation pond was based on sieve and hydrometer analysis <br />of various soil types in the Seneca II permit area. This <br />distribution is representative of the disturbed areas. Particle <br />size distribution for the gravel parking lots were based on sieve <br />analysis conducted on the gravel; the finer fractions were <br />estimated. Please refer to individual SEDCAD+ runs for <br />distributions. The specific gravity and the submerged bulk <br />specific gravity of the soil are estimated to be 2.50 and 1.25, <br />respectively. <br />The C and P Factors The C <br />factor, is the ratio of soil <br />cover and management to that <br />continuous fallow. <br />factor, the cover <br />loss from an area <br />from an identical <br />and management <br />with specified <br />area in tilled <br />The P factor, the support practice factor, is the ratio of soil <br />loss with a support practice like contouring, strip cropping, or <br />terracing to that with straight -row farming up and down the slope. <br />The C factor was determined based on the vegetation description in <br />Tab 10 and with the aid of the USDA -ARS revised USLE software <br />program for each cover type within the overall drainage area. The <br />P factor is based on current or future practice. Table 7 -6 -7 -4 <br />shows the results for the C and P factors for the various <br />subwatersheds. <br />TABLE 7 -6 -7 -4 <br />CP FACTOR <br />Vegetat Tvpe <br />Grass <br />r+ <br />Topsoil Removed <br />Disturbed Roads <br />7 -6 -7 -6 <br />NOR 006608 <br />CP <br />0.001 <br />0.600 <br />0.500 <br />Revised 08/20/93 <br />1 <br />