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Mr. Raul Passerini, P.E. Page 3 <br />June 24, 2015 <br />amount of 11.24 inches. Based on monthly average temperatures reported for the Dillon 1 E <br />station and the Green Mountain Dam station (see attached Table 1 for details), ice cover was <br />assumed for the months of December through March; therefore no evaporative consumptive <br />use was assumed for those months. For the purposes of this SWSP, the Applicant shall replace <br />the net evaporative depletions from the exposed ground water surface area that may occur <br />during the assumed ice cover period (December through March) for any time that the pits are <br />not completely covered by ice. The net depletion of ground water due to evaporation was <br />calculated to be 1.73 acre-feet per acre. The attached Table 2 displays the calculated unit <br />evaporation, the surface area of the cell ponds, and the monthly net evaporation <br />corresponding to 2015 and 2015. The net evaporation for the period of this SWSP is estimated <br />at 57.56 acre-feet per year. <br />Water Lost with the Mined Product <br />Everist plans to mine approximately 130,000 tons of material during the 2015 and <br />136,500 tons of material for 2016. Consumptive use associated with water retained in mined <br />material was calculated as 4 percent by weight for material mined below the ground water <br />table and 2 percent by weight for washed material mined above the groundwater table and <br />were determined to be approximately 3.44 acre-feet for 2015 and 3.62 acre-feet for 2016, as <br />shown on the attached Table 4. <br />Water Consumed by the First -Fill <br />For the Maryland Creek Ranch, the "first fill" was estimated based on 31,000 tons of <br />backfill material during the 2015 and 34,000 tons of backfilled material for 2016 multiplied by <br />the percentage gravel matrix (70% assuming a porosity of 30 percent and a density of the <br />material of 120 lb/cubic-foot) and then subtracting the volume of water lost with the mined <br />product for "Not Washed" gravel. Based on the above, the water removed by the "first fill" <br />was determined to be 16.49 acre-feet for 2015 and 16.93 acre-feet for 2016, as shown on the <br />attached Table 3. <br />Water Used for Concrete Production (from well permit no. 51594-F) <br />Water consumption associated with production of concrete was calculated assuming an <br />average of 30 gallons of water for one cubic yard of concrete. Therefore the net consumptive <br />use associated with production of 84,564 cubic yards of concrete during 2015 equals 7.79 acre- <br />feet and production of 88,792 cubic yards of concrete from 2016 will equal 8.17 acre-feet <br />(Table 5). <br />Water Used for Truck Washing (from well permit no. 51594-F) <br />Water consumption by concrete truck washing was estimated at 24.7 gallons of water <br />per cubic yard of concrete needed to wash the concrete trucks. Water utilized to wash concrete <br />trucks is collected from the wash area and is available for reuse. A 10 percent consumptive use <br />loss factor was applied to the total water used for the concrete truck washing. The estimated <br />losses for 2015 and 2016 are 0.64 acre-feet and 0.67 acre-feet respectively (Table 5). In <br />addition to the water consumption by concrete truck washing, water consumption due to <br />regular vehicle washing was estimated at 0.1 acre-feet per year which will come from well <br />permit no. 51593-F. <br />Water Used for Asphalt Production (from well permit no. 51595-F) <br />Water consumption associated with the asphalt production is estimated at <br />approximately 3 gallons of water per ton of asphalt. For 2015 the asphalt production is <br />estimated at 112,142 tons which will result in a water consumption of 1.03 acre-feet and for <br />