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4. Water Consumption for the Operation and Water Rights Issues <br />A gravel well permit is required from the Division of Water Resources for the Otter Creek Pit. <br />This section of the Colorado River is underappropriated, so a Substitute Water Supply Plan or <br />Augmentation Plan is not required. <br />This application is enclosed in Appendix 1. <br />Since the mine will encounter water in the mining operation below 4 -25 feet of excavation, and <br />permanent lakes will be left as part of the reclamation plan, it is demonstrated in this section that <br />that there are two separate calculations of consumptive use for both of these cases The well <br />permit will cover pit pumping as well as all consumptive uses for the operation. During the <br />mining stage of the project, consumptive uses will be limited to the evaporation from the <br />sediment pond, road watering, plant water sprays, washing aggregates and gravel retention. After <br />mining, the consumptive use will be lake evaporation. All consumptive uses are shown below: <br />1) The permanent lakes will total approximately 56.6 acres in surface area size, which may <br />fluctuate depending upon the groundwater level. Since the lake bottoms and sides are <br />always saturated due to the level of alluvial water, no losses will occur due to infiltration. <br />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 <br />pond will evaporate 55 inches per year or 4.58 acre -feet of water surface. This results in a <br />consumptive use of 259 acre -feet annually using an area of 56.6 acres. <br />2) During mine operation, consumptive use will occur as result of mining the gravel <br />exposing it to air before it runs through the crushing/screening operation and trucked off <br />site. It is far below what the evaporation is from the lake surface; therefore it does not <br />count in the worst case calculations. It is estimated that the gravel will contain 20% <br />moisture when it I excavated below water level but 16 % moisture will seep back into <br />ground at the location, leaving 4% of the aggregate weight mined to exit the property <br />with the end product as consumptive use. The use is calculated as 1 acre foot per 38960 <br />tons per year mined and sold. The use will be based on the highest expected average <br />Otter Creek Pit December 12 G - <br />