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1 <br /> GeoHydrologic Consultants, Inc <br /> Table 7.4-2 Pumping Test Results for Recovery EW-5S <br />' Aquifer Parameters Pumping <br /> Transmissivity (ft2/day) 300 <br /> ds=2 92 <br />' Hydraulic Conductivity(ft/day) 0 075 <br /> Groundwater Velocity(ft/day) 000098 <br /> Stagnation Point (ft) 655 <br /> 7.5 Groundwater Results <br /> The analytical results for the groundwater samples collected at beginning and at the end <br /> of the pump test from EW-5S are summarized in Table 9 Laboratory reports and chain- <br /> of-custody documentation are included in Appendix F <br />' The sample results indicated that moderate to high concentrations of TPHg, BTEX, and <br /> MTBE were detected Concentration for TPHg in groundwater at the beginning of the test <br />' was recorded to be 85,900 gg/L and at the end of the test it was 99,500 gg/L A similar <br /> increasing trend was observed for benzene (14,400 gg/L to 17,300 gg/L), toluene (7,560 <br /> gg/L to 9,000 gg/L), ethylbenzene (2,010 gg/L to 2,050 pg/L), xylenes (10,800 gg/L to <br />' 10,900 gg/L), and MTBE (3,420 gg/L to 4,430 gg/L) <br />' 8.0 AQUIFER TEST CONCLUSIONS <br /> Based on the sediment types identified in the drilling logs, the aquifer properties <br />' calculated within the screened interval of EW-5D (65-85 feet) appear to be representative <br /> of actual Site conditions within this deeper zone unconfined aquifer Based on the <br /> drawdown data from extraction well EW-51) and observation wells TB-7 and TB-10, Site <br />' aquifer conditions are represented by average T= 772 ftz/day, average K = 19 30 ft/day, <br /> average S= 0 034, average V =0 248 ft/day, and the average stagnation point is <br /> approximately 381 feet from the pumping well This stagnation point however assumes <br />' the pumping well is at steady state conditions that may not be actually achieved for many <br /> days to weeks of constant pumping Sediment types would be characterized as silt to <br /> medium grained sand according to these values, which are consistent with the sediments <br />' encountered within the borehole from depths within the screened zone of well EW-5D <br /> Based on the drawdown and recovery data from extraction well EW-5S, Site aquifer <br />' conditions within this area of the shallower zone unconfined aquifer are represented by <br /> an average T = 3 69 ftz/day, an average K = 0 093 ft/day, and an average V= 0 0012 <br /> ft/day, and an average stagnation point of approximately 551 feet from the pumping well <br />' This stagnation point however assumes the pumping well is at steady state conditions that <br /> ITOC 171 Pilot study Page 23 <br />