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Delineation and Destruction Work Plan for Well B-1 unauthorized release, the area was leased by Empire Real Estate (former site owner) to Premium Truck Repair(Figure 2). In addition to this outside storage area,Premium Truck Repair also leases the south end of the former galvanizing building and one of the office buildings on former Pond 2 North (next to well KEW-2U). 1.3 Well Construction and Borehole Log Well B-1 was installed in 1986 to a depth of 56 feet below ground surface (bgs). The borehole diameter was 8 inches. The well was constructed with 2-inch-diameter schedule 40 polyvinyl chloride (PVC) casing. The PVC casing was set approximately 0.3 feet from the bottom of the borehole. The well screen was hand-slotted schedule 40 PVC casing with slots approximately 3 inches apart, and was set from 45.7 to 54.7 feet bgs. The well was completed approximately 1.3 feet above ground surface. The top of the well casing was surveyed at 20.89 feet above mean sea level (msl). The current owner graded and filled in portions of the site soon after acquiring it in 1999. The ground surface around well B-1 was raised, and the completion for well B-1 was redone, including extending the well casing (by approximately 0.4 feet) and installing a new well vault. The top of the well casing is currently at 21.28 feet above msl. The B-1 borehole log (Appendix A, Borehole Log for Well B-1) indicates that hard, laminated silts and silt described as "stiff' were observed between 34.5 and 56 feet bgs. Based on this description of the lithology surrounding well B-1 at depth, it is unlikely that the oily substance would be able to migrate far from the well. 1.4 Historical Water Levels Depth-to-water measurements in well B-1 since 1992 have ranged from approximately 38 to 51 feet bgs. Approximately 70% of depth-to-water measurements since 1992 have been reported as dry, which corresponds to 51.09 feet bgs. The most recent depth-to-water measurement, determined on May 8, 2017, was 38.15 feet bgs; this corresponds to a water level elevation of 16.87 feet below msl,which is the highest ever recorded. The second highest was 18.32 feet below msl in April 1999. 1.5 Historical Water Quality Well B-1 was sampled six times since its construction in 1986. Since at least 1996, sampling of well B-1 has not been required per the Regional Water Quality Control Board monitoring and reporting programs and DTSC post-closure permits. Well B-1 was most recently sampled in May 2017, and the results are discussed in Section 2.3, May 2017 Groundwater Sampling Results. 10886-7 DUDEK 2 January 2019