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Appendix D - MW9 Pumping Test 2 <br />• 3. RESULTS <br />3.1 Drawdown <br />Data from the pumping test were analyzed to assess the hydraulic characteristics of the alluvium and fill in <br />the vicinity of MW9. Plots of water level versus time are provided in Attachment 1. As shown on these <br />plots, water levels in the vicinity of Sumps 1, 2, and 3 had not fully recovered prior to the start of the MW9 <br />pumping test. Several of the plots show extrapolated pre-pumping water levels, so that the drawdown <br />during the pumping and recovery period can be computed. <br />The maximum drawdown observed at each well and sump during the test is shown in Table 2 and Figure 2. <br />3.2 Distance-Drawdown Analysis <br />A distance-drawdown plot for wells MW6, MW9, and Sump 2 is presented in Attachment 2. This data was <br />analyzed using the Jacob (1947) method. Results of the distance-drawdown calculations show an estimated <br />hydraulic conductivity of 107 gpd/ft2, or 5x10-3 cm/sec and an estimated specific yield of 0.02. <br />3.3 MW9 Drawdown Analysis <br />Water level drawdown in MW9 was analyzed using the Jacob method (Figure 2). The results indicate that <br />the hydraulic conductivity of the alluvium and fill in the vicinity of MW9 is approximately 163 gpd/ft2 or <br />7.7x10-3 cm/sec. <br />3.4 Water Quality <br />• Field parameters and uranium were monitored in the pumping well discharge. The data are presented in <br />Table 3 and Figure 3. <br />In Ralston Creek, pH decreased slightly but remained near neutral throughout the pumping test and <br />recovery period. Conductivity in Ralston Creek increased from 320 at the start of the pumping test to 600 <br />at the end of the recovery test at Station SW-BPL (Figure 4). <br />4. CONCLUSIONS <br />The MW9 pumping test data suggests a preferential radius of influence in a northeasterly direction along <br />the axis of the valley. Results of the aquifer test analysis indicate a mean hydraulic conductivity of 135 <br />gpd/ft2 or 6.4x10-3 cm/sec and an estimated specific yield of 0.02. <br />5. REFERENCES <br />Jacob, C. E., 1947. Drawdown Test to Determine Effective Radius of Artesian Well, Trans. American <br />Society of Civil Engineers, v. 112, paper 2321, pp. 1047-1064. <br />LJ <br />4109B.071116 Whetstone Associates