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SITE CLOSURE EVALUATION REPORT Beacon Station No.502 35 North Cherokee Lane Lodi, California Delta project No. D093-907 ' 2.3 Site Vicinity Well Inventor According to a representative of the City of Lodi Department of Public Works there is one municipal ' water supply well within a 2,000 foot radius of the site. This well is located approximately 1,500 feet southwest of the site and is screened from 140 feet to 460 feet below surface grade (bsg). No other wells are believed to exist within a 2,000 foot radius of the site. Water in the vicinity of the site is Supplied by the City of Lodi and is obtained entirely from municipal supply wells. ' 3.0 SUMMARY OF 1N=IGATION RESULTS ' 3.1 Site Geology Soils beneath the site are predominantly silt and silty sand to a depth of approximately 20 feet bsg, clay from approximately 20 feet bsg to 35 feet bsg, and sand and silty sand from approximately 35 feet bsg ' to greater than 60 feet bsg. Geologic cross-sections have been prepared to illustrate the inferred subsurface conditions at the site. A geologic cross-section location map is presented as Figure 3, and geologic cross-sections A-A' and B-B' are presented in Figure 4. ' 3.2 Site H dro eolo The depth to ground water was approximately 40 feet bsg when the first monitoring wells were installed ' in October 1986; however, the depth to ground water has increased over the years and is now approximately 55 feet bsg. A summary of available ground water elevation data is presented in Table 1. ' Ground water has typically flowed toward the southwest or southeast across the site. ' 3.3 Distribution of Petroleum H drocarbon in Soil A summary of analytical results for soil samples is presented in Table 2. Soil boring locations and m ' locations of soil samples collected from excavations are shown in Figure 5. ' Analytical results indicate that concentrations of petroleum hydrocarbons greater than 100 milligrams per kilogram (mg/kg) were present only in soil samples collected from the north end of the fuel tank location ' at depths of 20 feet bsg or less. The approximate lateral extent of soil containing petroleum hydrocarbons in concentrations greater than 100 mg/kg prior to site remediation is shown in Figure 6, and the ' RPT 139.SJS