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C}'CC - .Sediment Yield Demansrration Eckman Park Area 41 <br /> <br /> <br /> <br />3.0 RESULTS <br />3.1 SEDCAD+MODELING <br />The following table summarizes the model inputs and results for the l0-year, 24-hour storm event for the Area 41 <br />reclaimed areas: <br />AREA 41, SEDIMENT YIELD DEMONSTRATION <br />INPUTS AND RESULTS <br /> Runoff Peak Slope Avg. Sediment <br />Area Size Tc CN Volume Q K Lengt Slope CP Yield <br /> (ac) (hrs) (ac-R) (cfs) h (%) (tons/ac) <br /> (rt) <br />Area 41 1 0.005 61 0.00 0.00 0.21 52.18 12.13 .094 0.0 <br />Avg. Slope, Soil "B" <br />Pasture Reference Area I 0.023 1 0.00 0.00 0.32 08.7 12.13 .058 0.0 <br />Avg. Slope, Soil "B" <br />Eckman Park & Mine 1 l 0.057 6l 0.00 0.00 0.21 52.18 49.1 .094 0.0 <br />Max. Slope, Soil "B" <br />Pasture Reference Area l 0.011 61 0.000 0.00 0.32 208.7 49. I .058 0.00 <br />Max. Slope, Soil "B" <br />Pasture Reference Area I O.OI 1 80 0.040 0.50 0.32 208.7 49. l .058 0.00 <br />Max. Slope, Soil "D" <br />In order to acwunt for the diversity of the reclaimed areas, models were developed for the average and maximum <br />slopes measured for Eckman Park. The Pastureland Reference Area information vas modeled using the same <br />slopes for comparison. As previously noted, the majority of the pre-mining topsoil vas Hydrologic Soil Group B <br />while the Pastureland Reference Area is located in an area with topsoil classified as Hydrologic Soil Group D. <br />The curve number (CN) for pastureland with Hydrologic Soil Group B in good wndition is 61 and the CN for <br />pastureland ~~~th Hydrologic Soil Group D in good condition is 80. When the reclamation and reference area <br />models were run with a CN of 61, the models indicated no runoff or sediment transport from the unit areas. The <br />CN was increased to 80 for the Pastureland Reference Area_ for an additional comparison of runoff and sediment <br />transport to the reclamation results. <br />• i:'•rn~e,nironmmialb.km•Mmdrd~iraa Ldo: <br />