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7� U 0 Beacon Station No.474 June 5, 1998 Stockton,California Work Plan definition. Borings B-5 and B-6 were drilled at the north end of the east and west dispenser islands, respectively (Figure 2). Borings B-5 and B-6 were each completed with three nested soil vapor extraction wells, VW-1, VW-2, VW-3, and VW-4, VW-5, VW�6, respectively. Detectable concentrations of gasoline-range hydrocarbons were found to be present in the soil and groundwater during these previous site investigations. Locations of the soil borings, R groundwater monitoring wells, and vapor wells are shown on Figure 2. Groundwater was found to be present at a depth of approximately 80 feet below surface grade (bsg) in 1993, and approximately 68 feet bsg in 1996. Quarterly monitoring on March 31, 1998 has ,g 'i indicated the average depth-to-water beneath the site to be approximately 62 feet bsg (see Table I in Appendix B), and the groundwater flow direction is predominantly toward the J. south-southeast. SCOPE OF WORK j To evaluate soil characteristic's and possible alternatives for remediation of petroleum hydrocarbons in soil and groundwater at the site, Horizon proposes to perform the following work scope: J Task I Obtaining well per"mits from the SJC PHS/EHD,.submitting notification to the SJVAQMD, preparing a site-specific health and safety plan, notifying Underground Services Alert (USA), and scheduling a drilling contractor. Task 2 Drill an 8-inch diameter soil boring AS-1 at the proposed location shown on Figure 2. Based on the historical groundwater levels (Appendix B), soil boring AS-1 will be drilled to an approximate depth of 85 feet bsg and completed with 4 a maximum of five feet of 2-inch inside diameter (ID) poly vinyl chloride (PVC) well screen with factory 0.010-inch slots. The approximate screened 1474-22.wp 3 HORIZON ENVIRONMENTAL INC.