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V 0 <br /> l� A S S O C I A T E S I N C <br /> GROUNDWATER FLOW DIRECTION <br /> Water level measurements were collected from wells MWl through MWS on March 23, 2001 <br /> Water levels ranged from 21 48 to 22 37 feet below the tops of the well casing elevations, <br /> representing an average decrease in the water table elevation of approximately 0 05 feet since <br /> December 2000 The water level data were used to develop the groundwater elevation contour <br /> map (Figure 2) Assuming that horizontal isotropic conditions prevail, groundwater in the <br /> uppermost aquifer beneath the site flowed towards the southwest The average hydraulic gradient <br /> on March 23, 2001 was calculated to be 0 0005 ft/ft or approximately 3 ft/mile A summary of <br /> groundwater monitoring data is presented in Table 1 <br /> ANALYTICAL RESULTS <br /> The groundwater samples collected from well MW2 contained TPHd at a concentration of 310 <br /> parts per billion (ppb) The groundwater sample collected from well MW2 also contained <br /> detectable concentrations of TPHg at 3,400 ppb and toluene, ethyl benzene, and xylenes <br /> concentrations ranging from 1 0 ppb to 250 ppb The groundwater samples collected from wells <br /> MW 1, MW3, MW4, and MWS contained no detectable concentrations of TPHd, TPHg, or <br /> BTEX Analytical results of groundwater samples are summarized in Table 2 and laboratory <br /> • data sheets are contained in Attachment 2 <br /> CONCLUSIONS <br /> Concentrations from wells MW1, MW3, MW4, and MWS remained consistent with the previous <br /> sampling event Concentrations in well MW2 of TPHg and BTEX have decreased significantly <br /> since the previous sampling event and are consistent with the concentrations during first, second, <br /> and third quarters 2000 The direction and magnitude of groundwater flow is consistent with the <br /> previous event Groundwater elevations have decreased since December 2000 The hydrocarbon <br /> plume appears to be limited to the immediate vicinity of well MW2 and this has been verified <br /> with five quarters of groundwater monitoring <br /> RECOMMENDATIONS <br /> Based on the results of the first quarter 2001 monitoring episode and the results of the previous <br /> four quarters of groundwater monitoring, it appears the hydrocarbon plume in the groundwater is <br /> stable and we recommend the site be granted closure <br /> w\I30991quartlyllgr-2001 dvc 3 <br />