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ATC ENVIRONMENTAL • GEOTECHNICAL BUILDING SCIENCES • MATERIALS TESTING L7 Lone Palm Avenue, Suite 201B Modesto, CA 95351 Telephone 209-579-2221 Fax 209-579-2225 www.ategroupservices.com include three in the up-gradient or immediate cross-gradient direction to the west and north of the former USTs, and six borings in the down-gradient and extended cross-gradient direction to the east and northeast of the former USTs. Proposed boring locations are shown on Figure 2. Three of the borings will be advanced using cone penetrating test (CPT) methods. The CPT borings will be advanced to an estimated depth of 60 ft bgs (or refusal). The borings will be advanced using a direct push CPT rig that will log soil lithology from approximately five feet bgs to the maximum explored depth. Groundwater samples will be collected from separate boreholes advanced adjacent to the CPT boring, and from the additional six locations, using a modified HydroPunch® sampler. Prior to groundwater sampling, a water level meter will be used to confirm that the drive rods do not contain water. The sampler will then be driven to approximately three feet below the desired sampling depth, and retracted three feet to expose the disposable schedule 20 polyvinyl chloride (PVC) screen and allow for groundwater to enter the HydroPunche sampler. The water sample will be collected by lowering a 3/4-inch diameter stainless steel bailer through the drive rods to groundwater. The groundwater will be bailed from the drive rods, decanted from the bailer into 40-milliliter (ml) volatile organic analysis (VOA) vials. Following the collection of the sample, the drive rods will be retracted, leaving the disposable drive tip and four-foot length of PVC well screen in the hole. Following completion, the borings will be grouted through the drive rods from the total depth explored to surface grade with neat cement. ATC anticipates that a minimum of two groundwater samples will be collected from each boring at screened intervals between 40 and 60 feet bgs. Following groundwater sample collection, the borings will be backfilled with neat cement grout to the ground surface. Drill cuttings, if any, will be stored on- site in 55-gallon containers pending laboratory results after which disposal arrangements will be made. Laboratory Analysis Groundwater and soil samples collected will be submitted for chemical analysis and be sent under chain- of-custody documentation to a California state certified laboratory. Samples will be collected and analyzed for TPHg, BTEX, and fuel oxygenates, including MTBE and TBA, using EPA Method 8260. Reporting Following the completion of the field activities, ATC will submit a summary report. The report will include CPT and boring logs; tabulated vapor, soil, and groundwater analytical results; chain-of-custody documentation, conclusions and recommendations for future work, if needed. SCHEDULE Boring permits will be obtained from the San Joaquin County Environmental Health Department prior to the commencement of drilling activities. Upon approval of this work plan, ATC will immediately submit permit requests and begin to implement the scope of work. A report summarizing the work will be submitted approximately 4 weeks following receipt of the analytical results. S: \62596 \reports \SVIS_WP_ADD-2016.doc 5 ATC