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i 08 January 2001 AGE-NC Project No 97-0249 iPage 4 of 5 ' 4.0. SUMMARY AND CONCLUSIONS The Implications from the December 2000 ground water monitoring event are as follows ' Ground water flow direction for the area bound by Three B's Truck PIaza wells MW-1 through MW-6 and Flag City Chevron wells MW-7, MW-12A and MW-13A was generally ' toward the east-southeast at a gradient of 0 001 ft/ft,or approximately 5 feet per mile and less (Figure 3), due to the low gradient at the site, slight variations In ground water measurements or changes of recharge/discharge of the local ground water could greatly modify ground ' water flow direction • Ground water flow direction at the site may have been Influenced by pumping of the Rocky's Restaurant (14659 Thornton Road, Lodi CA) domestic drinking water well and by ground water extraction activities at Flag City Chevron (6421 Capitol Avenue) • The ground water elevation at the site was within the screened Intervals of wells MW-1 ' through MW-6 and is representative of shallow ground water conditions • Ground water elevation at the site Increased an average 3 93 feet from the August 2000 ground water monitoring event to the December 2000 ground water monitoring event The lateral extent of the dissolved petroleum hydrocarbon plume Is not known toward the south, southwest, west, northwest, north and northeast of the area bound by wells MW-1 ' through MW-6, the vertical extent Is not known In any direction • The elevated petroleum hydrocarbon concentrations detected In water samples collected from ' wells MW-1, MW-2, MW-3 (screened between 5 and 25 feet bsg) suggest that these wells may be screened within or near the "core area" of the dissolved petroleum hydrocarbon plume The area of greatest dissolved petroleum hydrocarbon-Impact was observed In the ' area near MW-3 (Figure 4) • Elevated concentrations of dissolved petroleum hydrocarbons were detected In the samples ' collected from well MW-6, the TPH-g Isoconcentratlon contour map (Figure 4) suggests a second dissolved petroleum hydrocarbon plume In the area of MW-6 ' The highest concentrations of MTBE were detected In the samples collected from wells MW-4 and MW-6 and lower concentrations detected at wells MW-1 and MW-2, this suggests separate MTBE plumes being pulled towards domestic drinking water wells RDW-1 ' (Rocky's Restaurant) and DW-1 (Three B's Truck Plaza) • Laboratory results of the grab water sample collected from DW-1 suggest that there Is no MTBE-Impact to the Three B's Truck Plaza domestic drinking water well at this time, however, MTBE has consistently been detected in the Rocky's Restaurant drinking water well since February 1999 (Table 3) ' Advanced GeoEnvironmental,Inc