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the petroleum hydrocarbons by soil venting Injecting treated water into upgradient wells (IWl, <br /> MW4, MW7) will reverse the hydraulic gradient, preventing the plume from upgradient <br /> source(s) from migrating toward former Exxon RS 7-3942 <br /> t1.4 WELVAQUIFER HYDRAULICS <br /> To determine the capacity of recovery wells RW1, RW2, and RW3 and aquifer transmissxvity, <br /> several bail tests were conducted. A pumping test was subsequently completed on these wells to <br /> refine the estimates of transmissivity and to provide an operational estimate of radii of influence. <br /> An injection/percolation test was also performed in the upgradient well MW7 The rate of addi- <br /> tion of water to MW7 and the subsequent rise of water observed in MW were used to determine <br /> the volume of groundwater that can be reinjected in this area and how injection may affect <br /> tgroundwater elevations <br /> 1.4.1 Bail Tests <br />' <br /> Sampling and Testing <br /> P g <br /> The three new recovery wells (RW1, RW2, and RW3) were bail tested on 31 May 1990 The <br /> tests were accomplished by quick extraction of a known volume of water from the well using a <br /> 3-inch-diameter PVC bailer, the recovery of the water level in the well was recorded with pres- <br /> sure transducers and a HERMIT 1000B Environmental Data Logger. The data collected (residu- <br /> al drawdown vs time) were interpreted in terms of aquifer transmisslvity and storativtty using <br /> the Well Hydraulic Interpretation Program (WHIP) of Hydro-Geo, Chem , Inc. The details of <br /> the tests and their interpretation are in Appendix B. The values of calculated transmissrvtties are <br /> summarized in Table 2. <br /> Transmissivity values ranged from about 11 to 400 fO/day for 20 feet of aquifer screened by the <br /> wells Transmissivity values for the new recovery wells are higher than those of previously <br /> tested wells (MW1, MW2, MW3, and MW6), because of the larger screened intervals (aquifer <br /> thickness), the values for hydraulic conductivity, which is independent of thickness, ranged <br /> between 3 ft/day (MW6) and 30 ft/day (MW3) <br /> 1.4.2 Groundwater Pumping Test <br /> 1 <br /> Field Sampling <br /> To better determine the hydraulic properties of the saturated zone under former Exxon RS <br /> 7-3942 and to size the treatment system more accurately, EA conducted pumping tests in wells <br /> RW 1 and RW2 <br /> c6Wway/394yv191/tY 5 <br />