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1) The permanent lakes will total approximately 90-99 acres in size, which may fluctuate depending <br />upon the groundwater level. Total average water surface is expected to be 94.0 acres. Since the lake <br />bottoms and sides are always saturated due to the level of alluvial water, no losses will occur due to <br />infiltration. Losses will occur due to evaporation at the water surface. Based upon evaporation data <br />for this location from the State Engineers office and precipitation data for this area, this pond will <br />evaporate 55 inches per year or 4.58 acre-feet of water per acre of water surface. This results in a <br />consumptive use of 430.5 acre-feet annually using an area of 94.0 acres. <br />2) During mine operation, consumptive use will occur as a result of mining the gravel and exposing <br />it to air before it is run through the crushing/screening operation and trucked off site. It is far below <br />what the evaporation is from the lake surface, therefore it does not count in the worst case <br />calculations. It is estimated that the gravel will contain 20% moisture when it is excavated below <br />water level but 16%o moisture will seep back into the ground at the location, leaving 4% of the <br />aggregate weight mined to exit the property with the end product as a consumptive use. The use is <br />calculated as 1 acre foot per 38960 tons per year mined and sold. The use will be based on a higher <br />than average annual tonnage for the project or 480,000 tons per year. Therefore, this consumptive <br />use will be 12.32 acre-feet per year. This use will only occur for the years of mining. <br />3) Evaporation will occur as a result of pumping water into the sediment pond and exposing this <br />water to the surface. Most of the water will seep back into the ground, however, the surface area of <br />the pond will add approximately 1.0 acres. Using the rate calculated above of 4.58 acre-feet per acre, <br />this results in a use of 4.58 acre-feet per year. <br />4) Consumptive use for road dust control will be minor since the access road will be primarily <br />maintained with magnesium chloride and/or water as needed. Under very dry conditions and high <br />truck traffic, water may be used. This use is estimated at 19.0 acre-feet per year.. <br />5} Consumptive use for the asphalt plant, concrete plant and the screening/croshing plant dust <br />control sprays are expected to be 29.5 acre-feet peryear. <br />15 Road Pit 10/02 34 <br />