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15 May 2000 <br /> AGE-NC Project No 95-0167 <br /> ' Page 2 of 5 <br /> Results of laboratory analysis of additional `grab' ground water samples collected from up-gradient <br /> and down-gradient locations indicated limited ground water impact, however, the hydrocarbon- <br /> impacted water has migrated east and northeast from the dispenser area The highest concentrations <br /> ' of dissolved hydrocarbon compounds are in the area east of the former UST and dispenser locations <br /> near P6 (Figure 2) <br /> Hydrocarbons have been encountered in the down-gradient direction from the former dispenser, at <br /> the location of bonng P5 and further down-gradient at the location of boring PI Based on the data <br /> from the grab water sample collected from boring P7, TPH-g concentrations in ground water <br /> decrease westward of the former fuel dispenser (Figure 2) <br /> The installation and initial sampling of the ground water wells at the site was reported in Quarterly <br /> Report, dated 27 September 1999 and prepared by AGE <br /> ' 2 3 GROUND WATER DEPTH AND FLOW DIRECTION <br />'. The estimated depth to ground water at the site is approximately 10 to 15 feet bsg,based on the map <br /> titled Lines of Equal Depth To Groundwater, Fall 1997 published by the San Joaquin County Flood <br /> Control District and Water Conservation District, and information obtained from the PHS-EHD from <br />' monitoring wells at surrounding sites Furthermore, PHS-EHD records indicate that the highest <br /> observed ground water elevation at the property was 10 feet bsg,measured in 1986 During the initial <br /> site assessment conducted in September 1995, ground water was measured at approximately 25 feet <br />' bsg During the site assessment of April 1997, ground water was measured at approximately 15 feet <br /> bsg <br />' The prevailing ground water flow direction in central Stockton is generally toward the northeast, <br /> however, ground water flow direction may vary locally,possibly affected by season changes or due <br /> to tidal fluctuations Ground water is considered to be of beneficial use and is utilized for domestic, <br />' industrial and commercial purposes <br />' 3.0. SCOPE OF WORK <br /> The site investigation was conducted to assess the lateral and vertical extent of petroleum <br />' hydrocarbon impact to soil and ground water beneath and surrounding the former gasoline dispenser <br /> location at the site The scope of work conducted during the site investigation activities included <br />' 0 Collection of ground water samples from each of the monitoring wells, <br /> . Laboratory analysis of ground water samples for total petroleum hydrocarbons as gasoline <br /> 1 <br /> 1 <br />