Laserfiche WebLink
P = 1.0 <br />from the "C" Factors for Permanent Pasture and Rangeland EPA (1977) table on page <br />7. <br />This factor is only applicable when such practices such as contouring perpendicular to <br />the slope or other similar practices are used. None of these items are applicable to the <br />pre- mining case. Therefore, the "P" factor for both the pre -mine and mine cases is 1.0. <br />A = 26 x 0.39 x 0.39 x 1.0 x 1.0 = 3.95 tons /acre annually <br />Over a three year period, and across 5.5 acres, this gives a total sediment amount of 65.7 tons. <br />At roughly one ton for every 27 cubic feet of soil, the total sediment if 1774.3 cubic feet. This is <br />0.04 acre -ft. <br />The combined run -off (0.68 acre -ft) and sediment volume (0.04 acre -ft) is 0.72 acre -ft. Pond <br />015 is designed to hold 0.95 acre -ft without discharge, roughly 25% larger than the amount <br />required. The stage- storage report and graph are attached on pages 8 and 9 respectively. <br />The pond volumes were calculated from TIN surfaces in SurvCAD. Since the pond is temporary <br />and has such a large safety factor for the 100 year event, no spillways are required. <br />Water stored in Pond 015 will either infiltrate into the ground or evaporate into the air. No <br />discharge will take place at from Pond 015. The consumptive use of Pond 015 is covered under <br />the existing water augmentation plans for the New Horizon Mine. <br />The plan view of the pond is shown on Map 2.05.3(3) -15 <br />Revised May 2010 (PR06) Attachment 2.05.3(3) -22 -4 <br />