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1 <br /> 1 15 January 2002 <br /> AGE-NC Pr4Ject No 96-0232 <br />' Page 7 of 16 <br />' Joaquin County service area No 31 municipal water wells (CSA-1 and CSA-2) Quarterly ground <br /> water monitoring procedures for the site were outlined in the Work Plan Addendum, dated <br /> 28 January 1998, and approved by the PHS-EHD by letter dated 24 February 1998 A coordinated <br /> effort was made with Three B's Truck Plaza (14749 Thornton Road, Lodi CA) to conduct ground <br /> water monitoring activities concurrently, the Three B's Truck Plaza tabulated ground water elevation <br /> results are in Appendix F <br /> 3 1 WELL MONITORING AND PURGE PROCEDURES <br />' On 11 December 2001, depths to ground water were measured in the ground water monitoring wells <br /> from the tops of the well casings to the nearest 0 01-foot utilizing a Solinst water level meter The <br />' ground water elevation in each mornutonng well at the site was calculated by subtracting the <br /> measured depth to ground water from the surveyed well casing elevation (Table 4) Ground water <br />' elevations were plotted for the informal First Zone, Second Zone, Secondary Aquifer Zone and <br /> Primary Aquifer Zone hydrogeologic flow units as defined in Final Remediation Plan, <br /> dated 31 August 2000 Ground water elevation data was contoured on scaled site maps (Figures 3, <br /> 4, 5 and 6, respectively) <br /> On 12 and 13 December 2001, approximately 5 to 16 gallons of ground water(a minimum of three <br /> casing-water volumes per well)were evacuated (purged) from wells MW-1, MW-2,MW-4, MW-5, <br /> MW-6A, MW-613 and MW-7 utilizing disposable polyethylene bailers Temperature, pH and <br /> conductivity were measured for stabilization at regular purge-volume intervals from each well using <br />' an Oakton water analyzer Field data and logs are in Appendix G Monitoring well purged ground <br /> water was transferred to the ground water remediation system holding tank for treatment and <br /> disposal <br />' The multi-level monitoring wells MW-8 through MW-13 were purged by lowering and raising a <br /> 3/8-inch outer diameter, length-discrete polyethylene hose equipped with a ball-valve water tip <br />' through the top chambers into the specific water-charged screened section Approximately 1 to 4%2 <br /> gallons of ground water(a mi-mmum of three casing-water volumes per well) were purged from the <br /> multi-level monitoring wells Temperature,pH and conductivity were measured for stabilization at <br /> regular purge-volume intervals from each well using a Hydac water analyzer Field data and logs are <br /> in Appendix G Multi-level well purged ground water was transferred to the ground water <br /> remediation system holding tank for treatment and disposal <br />' 3 2 GROUND WATER SAMPLING <br /> Ground water samples were collected from the purged wells MW-1 through MW-7 utilizing new, <br /> Advanced GeoEnvaronmental,Inc <br />