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The site is located approximately one-half mile east of the San Joaquin River and is bordered on the west and south by shallow irrigation ditches and by agricultural fields. On January 1, 1988, when the excavation was sampled, standing water was present at a depth of approximately 11 feet. During the initial site visit on September 21, 1988, standing wag-ter was present in the excavation at a depth of approximately five feet. Mr. Iker stated that over the past few months he had observed water levels in the tank excavation rising soon after irrigation on the adjacent fields west and south of the site and he has observed water levels in the excavation falling between irrigation events. Observations of shallow groundwater within 5 to 10 feet of ground surface at the site concur with information obtained from the San Joaquin County Flood Control and Water Conservation District (SJCFCWCD) water table elevation map (Spring 1988) . Although the groundwater contours presented on the SJCFCWCD map do not extend as far west as the project site, contours in the vicinity of the site show a water surface elevation ranging from 0 to -10 feet MSL, based upon Spring 1988 well data.. Extrapolation of the contours presented on the SJCFCWCD water elevation map suggests that groundwater flows in a northerly to northeasterly direction beneath the site. As previously discussed, agricultural irrigation south and west of the project site appears to result in fluctuating groundwater levels. This localized recharge effect would be expected to result in groundwater flow paths that vary from northerly to northeasterly. California Water Service, supplier of domestic water in the Stockton area, has indicated that groundwater in the vicinity of the project site is generally considered of poor quality, due to saline intrusion from the Sacramento River Delta. California Water Service municipal supply wells are located over three miles east and northeast of the site and extend to depths of 400 to 600 feet. A review of San Joaquin Local Health District records indicates that one private well and two septic tanks are located within approximately 2,000 feet of the site. The private well is located at 2245 West Charter Way, at least 600 feet north of the tank site. One septic tank is located at 1904 West Charter Way and the other is at 2000 West Charter Way, both at least 200 feet east of the tank site. The Stockton Ford New Holland dealership has an on-site septic tank and leachfield, located near the front of the property approximately 400 feet north of the tank site, as shown on Figure 2. The dealership is serviced by underground electrical, natural gas, water, and telephone utility lines that lead to the office and shop building from West Charter Way, as shown on Figure 2. Underground Service Alert (USA) was contacted on September 16, 1988 by McLaren Environmental Engineering to have utilities marked by subscribing utilities. No markings were observed during the initial site visit. During the site visit Charles Iker identified the location of electrical and water lines in the vicinity of the former fuel island. 5 v