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1-3 Local Groundwater Flow Direction and Gradient The groundwater surface undulates slightly but has a gentle slope toward S50W with a gradient of 0 001 (Figure 4). This flow direction and gradient are consistent with published groundwater data from the City of Lodi(Environmental Forensic Investigations,Inc , 2002)and San Joaquin County Department of Public Works(2000)groundwater surface elevations for the North San Joaqum Water Conservation District I334 Petroleum Hydrocarbon Groundwater Plume The areal or horizontal extent of the petroleum hydrocarbon groundwater plume at the site extended throughout the site All monitoring wells except MW-4 had reportable concentrations of petroleum hydrocarbons Significant concentrations of TPH-gasoline and benzene were present in well MW-1, 2, 3, and 6 at concentrations above maximum contaminant levels (MCLs) Minor concentrations of 1,2- DCA ' and 1,2-EDB above MCLs were reported in monitoring wells MW I and 3 MTBE was reported to be present at low concentrations in MW-2 and MW-3 A review of past groundwater petroleum hydrocarbon concentrations was made and included m the tabulations presenter)in Table 4 No horizontal )unit of the petroleum hydrocarbon contamination plume has been identified to date The past maximum areal extent of the groundwater petroleum hydrocarbon plume as determined from previous work suggests the site to has had a minimum areal extent of approximately 200 by 225 feet(45,000 square feet) The horizontal extent of petroleum hydrocarbon contamination groundwater plume for this reporting period is estimated to be at least 13,600 square feet This minimum documented groundwater plume extent is about the same size of the previous monitoring event in the first quarter of 2004 � . The extent of the release is currently unknown and undocumented in both the vertical and horizontal extent It is unclear at this time if the site poses a threat to local water supplies_ 4.0 PLANNED FUTURE WORK The next planned operation for this site will include additional Quarterly Status Report(QSR)and quarterly monitoring report(QMR)for the period ending September 30, 2004 A sensitive receptor survey of the nearby water supply wells will be completed during the 3`d quarter of 2004 I Mau►iDTnvironmntarTPm arTexaoo\RepoM\063004QMR wpd 5