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C'YCC -Sediment Yield Demnnatrnrion Ednnnn Park .Area 41 • Where: ~. = Representative slope length (ft) m = 0.6 for Slope < l0 percent m = 0.5 4 percent < slope <_ !0 percent m = 0.4 Slope = 4 percent m = 0.3 Slope < 4 percent Slope Factor is a piece-wise linear relationship with the slope break point being at 8 percent, as shown on Figure 5.5, Slope Factor for the RULSE in the SEDCAD+ Users Manual. The sediment graph is then routed to a structure using an exponential decay procedure inwrporating deposition of a particle size distribution. The eroded particle size distribution is an input item. Inputs to the sedimentology component of the SEDCAD+ computer model include: • • • • • Particle Size Distribution Runoff Volume Peak Discharge Soil Erodibility Factor Representative Slope Length Average Slope Control Practice Factor Sediment Specific Gravity Particle Size Distribution. Particle size distribution analyses were previously conducted by CYCC on three soil samples taken from the mine area. SEDCAD+ does not consider particles larger than 4.0 mm as erodable, so the distribution has been adjusted with respect to the fraction smaller than 4.0 mm for input into the model. Analysis results are summarized in Appendix A, Table I. Runoff Volume, V. Runoff volume is calculated by SEDCAD+, as previously described in the Hydrology Section, and is considered to be an intemal input. Peak Discharge, Q. Peak discharge is calculated internally ~~~thin the SEDCAD+ program, as previously described, and is considered to be an intemal input. Soil Erodibility Factor, K. The K factors for Eckman Park ~+ere determined using a weighted average of the pre-disturbance soil types found in these reclaimed areas. Based on Routt County SCS designations, pre- disturbance soil types have the following factors: • i v~n~nt.'iroitntrnlalkd.nnhundrd:vea~ 1 d«: