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The permanent lake will be approximately 4.2 acres in size, which may fluctuate between 3.8 acres and 4.6 acres, depending upon [he river level. Since the lake bottom and sides are always saturated due to the level of alluvial water, no losses will occur due to infiltration. Losses will occur due to evaporation at the water surface. Based upon evaporation data for this location from the State Engi- neers office and precipitation data for this area, this pond will evaporate 2.23 acre-feet of water per acre of water surface. This results in a consumptive use of 9.365 acre-feet annually using an area of 4.2 acres. Additional evaporation will occur as a result of mining the gravel and exposing it to air before it is mn through the crushing/screening operation and trucked off site. This evaporation use is estimated at 4% of the annual excavated tonnage, which will be based on a higher annual tonnage than that shown for this permit (69,500 tons per year). The tonnage used will be 90,000 tons per year. There- fore, this consumptive use will be 4800 tons of water per year or 2.64 acre-feet annually. It is esti- mated that the gravel will contain 20% moisture when it is excavated below water level but 16% moisture will seep back into the ground at the location, leaving 4% of the aggregate weigh[ mined to exit the property with the end product as a consumptive use. Since full tonnage evaporation can- not take place at the same time that the lake is at full size, a highest consumptive use scenario is based on the lake being at full size while the operation is winding down in the second year, there- fore, adiscount of 50% is applied to the evaporation losses associated with the gravel mined. This results in 50% of 2.64 acre-feet or 1.32 acre-feet per year. Consumptive use for dust control will be minor since the access road will be primarily maintained with magnesium chloride. Under very dry conditions and high truck traffic, water may be used. This use is estimated at 0.3 acre-feet per year. The portable enclosed crosher and screen plant do use sprays for dust control, although the gravel will be somewhat wet after excavation from below water level, and the need for additional water in the operation will be minor. Estimated use for the crusher/screen plant is 2% of the annual tonnage run through the plan[, which, as described above will be a higher tonnage Than that of this permit, 120,000 tons per year. This results in an additional consumptive use of 1.76 acre-feet peryear. Piceance Pit 7/01 16