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Quarterly Groundwater Monitoring Report, September - November, 1992 January 22, 1993 <br /> Manna Pro, 4004 South EI Dorado, Stockton, CA 2 <br /> Status of Site Investigation and Cleanup Activities <br /> The fallowing activities were conducted during the quarter ending November 30, 1992 <br /> ■ Notified PHS (November 20, 1992, letter to Mr Steve Schneider) of intent to proceed <br /> with sod pile sampling and analyses as described in Task 1 of the Work Plan for <br /> Characterization and Remediation of StockQiled Sods and Tank Pit Excavation <br /> Backfilling, dated July 30, 1992 <br /> ■ Submitted a work plan to PHS (November 20, 1992, letter to Mr Steve Schneider) <br /> for Installing four groundwater monitoring wells to evaluate the lateral extent of <br /> groundwater contamination <br /> During the quarter from December 1, 1992, to February 28, 1993, the following work is anticipated <br /> i <br /> ■ Sample and analyze soil piles, <br /> ■ Submit report of soil pile analytical results and recommendations to PHS and <br /> Regional Water Quality Control Board (RWQCB), <br /> . ■ After PHS and RWQCB approval of recommendations, backfill excavation with <br /> approximately 1,200 cubic yards of fill material stockpiled on site (from unrelated <br /> construction activities) and excavated soils that meet the cleanup criteria, and <br /> ■ Install four groundwater monitoring wells to evaluate the lateral extent of <br /> groundwater contamination <br /> Groundwater Monitoring Data <br /> On October 29, 1992, the six existing groundwater monitoring wells were monitored for depth to <br /> water (DTW) The DTW measurements were taken from surveyed points at the top of each well <br /> casing, which are referenced to a common datum (designated as 100 feet) October 1992 <br /> groundwater elevations decreased an average of 1 5 feet compared with July 1992 elevations The <br /> results of groundwater monitoring are included in Attachment 2, Table 1 A potentiometric surface <br /> map, as interpreted from the data in Table 1, is presented in Attachment 1, Figure 1 As shown in <br /> Figure 1, the average groundwater gradient in the site vicinity is approximately 0 016 ft/ft toward the <br /> west-southwest The interpreted groundwater potentiometric surface suggests hydraulic mounding <br /> near, and potentially related to, the tank excavation <br /> R2819A2 DH <br /> GROUNDWATER <br /> TECHNOLOGY, INC <br />