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2. SEDCAD+ INPUT PARAMETERS COMMON TO ALL <br />ANALYSES <br />2.1 Storm Type <br />The Storm Type was selected as SCS Type 11. The SEDCAD+ model (hydrograph convolution interval) time <br />increment was selected as 0.1 hour. <br />2.2 Soil Type <br />The site is lopted within Soil Mapping Unit Number 31 (Permit). The soil type is representative of the <br />Holderness, Morop, Absarokee, and Work Series, among o[her similar soils (Permit). SEDCAD+ soil input <br />parameters include (Soils of Colorado, Loss Factors and Erodibiliry Hydrologic Groupings, 1983, Soil <br />Conservation Service) K (a measure of susceptibility of soil particles to detachmen[ and transport by rainfall <br />and runoff) soil erodibility = 0.32, and a hydrologic group of C. There is a large fraction of nibble size <br />material in the colluvium of [he site. For the purposes of the SEDCAD+ analysis, the 'erodible portion" of <br />[he material is classified as a clav loam soil. <br />A'type" particle distribution of the'erodible fraction",presented in the following [able, is used in this analysis. <br />Screen Sizes in mm Percent of Eroded Panicle Size Fraction Passing <br />4.00 100 <br />200 99 <br />L00 I 90 <br />0.500 88 <br />0.250 85 <br />o.12s ~ s2 <br />0.063 74 <br />0.016 56 <br />0.001 ~ 38 <br />0.0001 0 <br />2.3 Vegetation <br />The vegetation of the site is primarily oak brush with chokecherry and serviceberty. There is a good layer <br />(minimum of 2 inches) of brush litter on the ground. There is a small patch of Pinion • Oak in the area. <br />(Wac Elk SAE, tone Pine Gulch Developmen[ Waste Pile. Page 3 0[ 8) <br />