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design and performance requirements of the Colorado Mined Land Reclamation <br /> Division while utilizing as much of the existing structure and topography <br /> as possible. <br /> HYDROLOGY <br /> The hydrology of each watershed was analyzed utilizing the SEDIMOT II <br /> computer program. In performing this analysis, the characteristics of the <br /> minesite and reclamation procedures along with on-site sediment control <br /> procedures were considered. Addendums A and B contain complete listings <br /> of the SEDIMOT II inputs and outputs for the 10-year and 25-year design <br /> storms. Table 1 is a summary of these results. <br /> TABLE 1 <br /> Design Hydrology and Sedimentology Summary <br /> Structure 001 <br /> DESCRIPTION 10-yr-24hr 25yr-24hr <br /> Precipitation Depth 1.60-in. 1.80-in. <br /> Inflow Routed Volume 6.67-ac-ft 9.63-ac-ft <br /> Pond Volume At Peak Stage 10.08-ac-ft 12.97-ac-ft <br /> Peak Stage 9.12-ft 10.67-ft <br /> Peak Inflow Rate 27.33-cfs 48.26-cfs <br /> Peak Discharge Rate 0.81-cfs 0.88-cfs <br /> Basin Trap Efficiency 100.00 % --- <br /> Detention of Flow (Sediment) 49.70-hr --- <br /> Detention of Hydrograph Centers 15.22-hr --- <br /> In determining the hydrology parameters to be used as input to the <br /> SEDIMOT II computer program, each major watershed was subdivided into <br /> logical junctions, branches, structures, and subwatersheds. The basis <br /> of the subwatershed were drainage boundary, similar soil and vegetation <br /> type, and similar land use. The drainage area for this sediment pond <br /> was measured on 1-inch equals 400-feet and 1-inch equals 2000-feet <br /> topographic maps (see Exhibit 13-4 and Exhibit 13-6, respectively). <br /> In some instances, the mining will cause the drainage area to change <br /> during the life of the sediment structure. When the pit moves into the <br /> watershed, runoff is intercepted by the pit and diverted away from the <br /> 2 <br />