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Mr Ron Rowe C B R I A July 7, 1999 Pumping Test Equipment Groundwater was extracted from well EW-1 using a four-inch Grundfos electric submersible pump Water levels were recorded in the pumping well and the adjacent wells using pressure transducers and an In-situ Hermit two channel datalogger and two Troll dataloggers Water levels were also checked manually using an electric water-level meter Extracted groundwater was pumped into a temporary water storage tank Pumping Test Results During the step-drawdown test, the maximum sustainable flow rate in well EW-1 was approximately 12 gallons per minute (gpm) After allowing the well to recover from the step-drawdown test overnight, the constant-rate test was started at a discharge rate of 114 gpm, and continued at this rate for 9 hours The maximum drawdown measured in the pumping well was 4 98 ft Due to a faulty offset in one of the transducers, hand measurements were used for the EW-2 analysis The maximum drawdown measured in site observation wells during the pumping tests was 0 17 feet in well EW-2, 0 15 feet in well MW-1, and 0 05 feet in MW-2 No drawdown was observed in well MW-3 Before and after the pumping test, well EW-1 contained MTBE concentrations of 7,960 parts per billion (ppb) and 6,500 ppb, toluene concentrations of 6 67 ppb and 2 35 ppb, ethylbenzene concentrations of 186 ppb and <0 50 ppb and total xylenes concentration of 6 65 ppb and 168 ppb, respectively This suggests that MTBE concentrations in groundwater in well EW-1 decreased approximately 20% during the test, toluene decreased approximately 65%, ethylbenzene decreased at least 74%, and xylenes decreased approximately 75% Analytical results for the groundwater sampling are shown on Table 2 and included in Appendix C Cambria analyzed the drawdown data in wells MWA, EW-2 and MW-2 using the methods described by Copper and Jacob (1946) and Theis (1935) to calculate the transrrussivity and hydraulic conductivity of the water-bearing zone Similar calculations were performed on the recovery data from the step test in well EW-1 and MW-1, and the recovery from the constant-rate test in wells EW-1, EW-2, MW-1 and MW-2 using the method described by Theis and Jacob (1935) In addition, distance-drawdown analysis was used to determine efficiency of the pumping well The water level measurements and graphs are included in Attachment A The calculations are summarized in Table 1 Based on the calculations, the transmissivity and hydraulic conductivity of the water-bearing zone beneath the site are approximately 906 gallons per day per foot and 3 2 x 10 E cm/sec, respectively This hydraulic conductivity is within the range expected for well-sorted sands (Freeze and Cherry, 1979) Well efficiency was estimated to be approximately 16% i� 3