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for this permit 70,000 tons per year. Therefore, this consumptive use will be 4800 tons of water per <br />year or 1.54 acre-feet annually. It is estimated that the gravel will contain 20% moisture when it is <br />excavated below water level but 16% moisture will seep back into the ground at the location, leav- <br />ing 4% of the aggregate weight mined to exit the property with the end product as a consumptive <br />use. <br />3) Evaporation will occur as a result of pit pumping of water into the Famsworth Collection Ditch <br />and exposing this water to the surface. Since there is a wetland at the bottom of the Ditch, the in- <br />crease in area of exposed water is used to determine this consumptive use. This is approximately 0.3 <br />acres. Using the rate calculated above of 3.5 acre-feet per acre, this results in a use of 1.05 acre-feet <br />ep r <br />4) Consumptive use for dust control will be zero since no processing is done on this site and no road <br />application is needed since the material will be wet. Therefore, there will be no additional tonnage <br />processed for this application from that already allowed for mining at the Farnsworth #2 Pit. <br />The total consumptive use during mining is therefore 2.59 acre feet per year for an approximate pe- <br />riod of 4 years. After this time, pumping will stop and the lake will fill up. <br />Scenario 2 -After Minine <br />1) The permanent lake will be approximately 6.6 acres in size, which may fluctuate between 6.2 <br />acres and 6.7 acres, depending upon the river level and water inflow from imgation uphill. Since <br />the lake bottom and sides are always saturated due to the level of alluvial water, no losses will occur <br />due to infiltration. Losses will occw due to evaporation at the water surface. Based upon evapora- <br />tion data for this location from the State Engineers office and precipitation data for this area, this <br />pond will evaporate 42 inches or 3.5 acre-feet of water per acre of water surface. Since the existing <br />pond will be absorbed by the new lake and the pond already has adjudicated water rights, this area <br />must be subtracted. This is an area of 0.45 acres. Therefore, the area of new water surface is only <br />6.2 acres. This results in a consumptive use of 21.7 acre-feet annually. <br />Since the site was previously used for alfalfa irrigated field, the consumptive use for this past irriga- <br />tion is calculated at 1.72 acre-feet per acre per year of total effective precipitation and loss in the <br />plants. This is a credit of 10.66 acre feet per year. <br />North Fork Pit Mazch 04 19 <br />