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10. Response <br />a. The CDRMS requested annual pond survey data for the ponds receiving runoff from <br />the release area. The required water capacities and remaining capacities of the ponds <br />receiving runoff from the release area are attached. <br />11. The CDRMS requested an analysis, using a predictive model (SEDCAD or RUSLE), which <br />compares the suspended solids generated off the pre - mining land or comparable adjacent <br />areas, to the bond release area. Sage Creek believes the most appropriate metric generated by <br />predictive models is the total sediment load or yield, not the suspended solids. Tab 17, <br />Probable Hydrologic Consequences (PHC), of the Seneca II -W CDRMS Permit (No. <br />C1982057) includes a pre- and post - mining analysis of the change in sediment yield. Using <br />SEDIMOT II modeling (the predecessor version of SEDCAD), sediment yield was calculated <br />for Pond 005 and Pond 006 watersheds. Sediment yield is the amount of sediment (in tons) <br />removed from a watershed by flowing water per unit area (acres) in a given storm event. <br />Ponds 005 and 006 were selected for modeling when the PHC was first submitted and <br />approved because mining plans at that time contemplated disturbing approximately 80 <br />percent or more of the watershed above each pond. Results are summarized in the table <br />below. <br />* All conditions are run on a 10 year — 24 hour storm event. <br />'Total drainage area = <br />198.4 acres <br />Peak <br />Runoff <br />Sediment Yield <br />Watershed <br />Condition <br />729.9 acres <br />Discharge (cfs) <br />Volume (ac -ft) <br />(tons /acre) <br />0051 <br />Pre - mining <br />0.00 <br />0.00 <br />0.0 <br />005, <br />Postmining <br />0.20 <br />0.123 <br />0.0013 <br />0063 <br />Pre - mining <br />0.05 <br />0.020 <br />0.0002 <br />0064 <br />Postmining <br />0.98 <br />0.665 <br />0.0073 <br />* All conditions are run on a 10 year — 24 hour storm event. <br />'Total drainage area = <br />198.4 acres <br />2Total drainage area = <br />196.9 acres <br />3Total drainage area = <br />725.3 acres <br />4Total drainage area = <br />729.9 acres <br />