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Slope data from <br />Time of concentration three locations on Slope lengths and land use description inputs accurately <br />Summary pages in matched field data <br />the SEDCAD runs <br />Trapper modeled SEDCAD 4 for a 20 -acre study area having sedimentologic characteristics <br />representative of each bond release parcel. SEDCAD 4 calculated the peak settleable solids <br />concentration of runoff flowing to a single discharge point at the down - stream end of each 20 -acre study <br />area. SEDCAD 4 was run for pre and post mining conditions. The Division believes use of 20 -acre <br />study areas is a valid approach for modeling sedimentation in the reclaimed drainages in the bond release <br />area because it enables applying each block's actual vegetative cover data to the SEDCAD run for each <br />block. The total sediment load calculated for the pre- mining block A, F, K &Z RSAB &C 20 -acre study <br />area was 32.6 tons of sediment and 13.3 tons of sediment for pre- mining block A, F, K &Z RSAB &C. <br />TMI's SEDCAD 4 modeling concluded that the computed post- mining peak settleable solids generated <br />from each block is much less than the computed pre- mining value. <br />Trapper's SEDCAD 4 modeling concluded that the computed postmining peak setteable solids generated <br />from each block is much less than the computed premining value. <br />Based on Trapper's SEDCAD 4 modeling using baseline data, the Division finds that the lands proposed <br />for Phase II bond release are not contributing suspended solids to streamflow or runoff outside the permit <br />area in excess of premining levels. <br />