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the immediate vicinity of the excavation. Based on an analysis <br /> ' of the sands and gravels to be mined it is estimated that the <br /> maximum influence from dewatering will be 300 to 500 feet. <br /> Beyond this distance there will be no appreciable effect on <br /> groundwater due to mining. <br /> The distance from the mining area to a zero drawdown point is <br /> primarily a function of the depth of the saturated sand and <br /> ' gravel. This depth in turn governs the flow of groundwater <br /> through a given unit area. For thinner sections of sand and <br /> ' gravel there will be less groundwater flowing through the area <br /> and consequently there will exist a shorter radius of influence <br /> from the dewatering operation. For thicker sections of satur- <br /> ated sand and gravel there will be proportionately more ground- <br /> water flowing through the area and a correspondingly greater <br /> ' radius of influence from the dewatering operation. The estimated <br /> radius of influence of 300 to 500 feet was determined by placing <br /> a maximum drawdown of the groundwater system at the thickest <br /> ' section of sand and gravel; thus it represents the maximum <br /> radius of influence to be expected. <br /> ' The gravel mining operation is located downgradient from exist- <br /> ing domestic wells in the area. Groundwater moving through the <br /> valley recharges water levels in the project area. In this <br /> manner, the radius of influence from the dewatering operation <br /> will not extend permanently upgradient. <br /> ' G-2 <br /> 1 <br />