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<br />Limestone). Well MW-4 was installed in the eastern half of Cut 6 which was subsequently filled with <br />CKD/sludge. As the cut was filled, the monitoring well casings were continually extended above the <br />ground surface. These monitoring wells were abandoned in accordance with State regulations in April <br />1999. <br />Based on the water levels in the new monitoring wells (MW-5, -6, -7), ground water elevation estimates <br />in drill hole on the north end of Cut 7, and the elevation of the pond located in the southwest portion of <br />the quarry, the average ground water gradient across the mined portion of the site is on the order of 0.014. <br />Assuming that the ground water flow underneath and downgradient of the CICD/sludge landfills is in the <br />Codell Sandstone and using a porosity value of 30% (typical sandstone porosity of 5-30%, Freeze and <br />Cheny, 1979) the ground water velocity across the site is in the range of 0.05 to 0.2 feet per year. These <br />ground water velocity estimates are based on the range of hydraulic conductivity values (i.e., 0.15 to 3.3 <br />x 10$ ft/sec) estimated from the slug tests performed on monitoring well MW-5. These values fall within <br />the range of hydraulic conductivities for sandstone (i.e., 10~ to 10"10 ft/sec) given by Freeze and Cherry <br />(ibid.). <br />The amount of discharge from the sandstone aquifer into the Arkansas river can be estimated using the <br />values of hydraulic conductivity and ground water gradient discussed above. Additional parameters <br />needed to estimate the amount of discharge aze the aquifer thickness and width. In this case the width <br />used would be the length of the axis, perpendicular to the direction of ground water flow, through the <br />existing CKD/sludge landfills in Cuts 4 and 6. This width is estimated to be approximately 2000 feet. <br />The thickness of the aquifer would be the average thickness of the Codell Sandstone which, based on the <br />available information, we have assumed to be 25 feet. Using these parameters, and the range of estimated <br />hydraulic conductivities, the amount of ground water discharged into the Arkansas River would be on the <br />order of 2.5 to 11.25 cubic feet per second (cfs). The volume of flow in the Arkansas River reportedly <br />ranges from 50 cfs to 6000 cfs. Therefore, the dilution factor for ground water discharging into the river <br />would be on the order of 0.3 to 240 million to one (l). Any contaminants potentially released into the <br />ground water from the CKD/sludge landfills would, therefore, be diluted by these factors in addition to <br />the dilution which would occur when the landfill leachate reached the ground water. <br />KS-9903-02 Page 9 K-S &Company <br />Augus[16,1999 Copyright 1999 <br />