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Ground Cover (cover that contacts the surface) = Annual forbs + Perennial Grasses + Litter <br />+ Noxious Weeds <br />Ground Cover = 65.3% <br />Canopy Cover = Perennial Forbs <br />Canopy Cover = 23.4% <br />Using Table 3 and a canopy of 25% (short brush 0.5 meter in height) and the "G" canopy <br />type, the chart of Figure 1 was developed. From this chart, a ground cover that contacts the <br />surface of 65.3% yields a "C" factor of 0.03. Since the actual canopy is 23.4%, another <br />chart was developed from the data in Table 2 showing the change in "C" factor versus % <br />ground cover for a canopy of 0%. This is Figure 2, and using a ground cover that contacts <br />the surface of 65.3%, gives a "C" factor of 0.031. Since the actual canopy is 45.7%, a <br />simple interpolation is required to give the correct "C" factor: <br />0 "C" for canopy 0-25 = 0 "C" for canopy 0-23.4 <br />25 23.4 <br />0.001 = x x 0.000936 <br />25 23.4 <br />Therefore, the best "C" value for the post-mine irrigated pasture is 0.03-0.000936= 0.0299 <br />Summary of "C" Factors <br />Pre-Mine Irrigated Pasture 0.026 <br />Post-Mine Irrigated Pasture 0.030 <br />SL-12 CURRENT 11MAR11.wpd 24