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August 1994 -11- 933-2713.003 <br /> overlying a layer of clayey gravel. The lower clayey gravel unit exhibits a low permeability, <br /> indicating that this unit acts as an aquitard. Therefore, the groundwater is inferred to flow <br /> predominantly in the sandy gravel zone. The groundwater portion of conjunctive flow was <br /> determined to be significantly less than surface water flow in Cement Creek, even at low flow <br /> conditions and under the most unrealistically conservative conditions. <br /> Section 5.2 demonstrates that the lowest surface water flow is about 250 times higher than the <br /> reasonable estimate of groundwater flow presented above, and is about 45 times higher than the <br /> unrealistically conservative estimate of groundwater flow. High surface water flow is about <br /> 15,000 times higher than the reasonable estimate of groundwater flow and is about 2,500 times <br /> higher than the unrealistically conservative estimate of groundwater flow. These data suggest <br /> that groundwater flow is approximately 0.4% of the total conjunctive flow even during low-flow <br /> periods and therefore does not significantly affect the volume of conjunctive flow. <br /> Based on the results of conjunctive flow analysis, no further groundwater monitoring is <br /> recommended. Even under unrealistically conservative conditions, groundwater flow remains <br /> an insignificant portion of the total conjunctive flow in Cement Creek. Accordingly, monitoring <br /> of surface water flow in Cement Creek is sufficient to determine effects of adit plugging on the <br /> total flow in the creek. <br /> 6.0 REFERENCES <br /> Bouwer, H., and Rice, R.C., (1976). A slug test for determining the hydraulic conductivity of <br /> confined aquifers with partially penetrating wells. Water Resources Research, Vol. 12, <br /> No. 3, 423-428. <br /> Hvorslev, J. (1951) Time Lag and Soil Permeability in Groundwater Observations, Bulletin No. <br /> 36 Waterways Experiment Station, Corps of Engineers, U.S. Army, Vicksburg, <br /> Mississippi. <br /> Golder Associates <br />