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r <br /> 1 - Ill. CURRENT AND PROJECTED WATER REQUIREMENTS <br /> r <br /> Operators of the quarry have monitored water use over the November 1993 through <br /> October 1994 period to allow prediction of the anticipated maximum water use as a result of <br /> su expansion of the mining,activity. Water use was monitored over the winter period, including the <br /> months of November through March, and during the spring to fall period, during the months of <br />` April through October. Mine production was also monitored over this time period, so that water <br /> f use could be related to mine production. Table 2 presents the water use expressed in both acre <br /> feet per month and gallons per ton of material produced. <br /> Table 2 <br /> Current Water Use By Mining y g Activit y <br /> i <br /> CURRENT WATER USE UNIT WATER USE <br /> TIME PERIOD Ac. Ft./Mo. Gal/Ton <br /> Nov- Mar 7.19 169.76 <br /> { Apr- Oct 25.93 505.04 <br /> Annual Total 217.46 Acre Feet <br /> The primary use of the water supply is for washing of the aggregate and maintaining the <br /> moisture content of the aggregate above 2'/2%. Water is consumed by adsorption by the <br /> _ aggregate or by evaporation during the wash process and from the stockpiles. <br /> F <br /> A certain portion of the well water supply is returned to the aquifer by way of percolation <br /> F through the bottom of the sedimentation pond, which operates when the plant is processing <br /> aggregate. Brown Sand, Inc. measured the percolation in the pond at 3-inches overnight during a <br /> 12-hour period during the month of April, 1995. The measured loss is assumed to occur solely a <br /> due to percolation, since evaporation over the period was negligible. Extending this loss rate to a <br /> full year results in an annual percolation loss of 182.5 acre feetear per acre er or 548 <br /> p p Y acre feet <br />,..y for a typical 3 acre pond. Since this amount of loss exceeds the total water supply of 217_ acre <br /> - feet, it can only be concluded that the percolation pond is not in operation a full 365 <br /> days per <br />►-9 year. It is verification that significant percolation does occur, which recharges the groundwater <br /> J j <br /> STODDARD&ASSOCIATES Assessment of Water Supply Impacts AUGUST 1995 PAGE 5 <br /> i Iy <br /> A <br />