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August 1994 -10- 933-2713.003 <br /> Entire Thickness of Cement Creek Sediments <br /> A higher estimate of groundwater flow can be obtained by assuming that the entire thickness of <br /> Cement Creek sediments contributes to conjunctive flow and that all of the sediments are sandy <br /> gravels. This is an unrealistic scenario given the hydrogeologic data for the area, yet is useful <br /> for determining the highest possible groundwater flow. Based on Figures 2 and 3, the average <br /> cross-sectional area of Cement Creek sediments is about 31,000 ft2. Assuming that all of the <br /> sediments were sandy gravels, a hydraulic conductivity of 2.8 x 10' cm/sec (5.5 x 10' ft/min) <br /> would be representative. A representative hydraulic gradient would be about 0.03 ft/ft, based <br /> on ground surface elevations and assuming that the groundwater completely saturated the Cement <br /> Creek sediments up to ground surface. Utilizing these extremely conservative assumptions, the <br /> volume of groundwater flow is calculated to be 5.5 x 10' Mgd (5,515 gpd) as follows: <br /> Q = (5.5 x 10' ft/min) * (0.03) * (31,000 ft.2) * = 0.5 ft3/min = 3.83 gpm = 5,515 <br /> gpd = 5.5 x 10' Mgd <br /> 5.2 Surface Water flows <br /> Surface water flows are measured at CC-1 (Figure 1), which is located approximately 60 feet <br /> south of Section AW. Surface water flow data from 1992 and 1993 at CC-1 are shown on <br /> Figure 4. Figure 4 shows the high flow in the creek at CC-1 to be 13 Mgd (13,000,000 gpd) <br /> in the Spring of 1993. Average low flows for 1992 and 1993 were approximately 0.25 M-d <br /> (250,000 gpd). <br /> 5.3 Conclusion and Recommendation <br /> In summary, the geologic information and water level data collected during the field <br /> investigation in March, 1994 were effective for the calculation of the conjunctive flow. The <br /> field investigation revealed a sandy gravel zone underlying a clayey gravel till material and <br /> Golder Associates <br />