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Mr. Harlin Knoll August 29, 2001 . 2°d Quarter 2001 QMR Project No. 2007-0065-01 Page 2 On May 4 and 5, 2000, Stratus supervised the installation of two groundwater monitoring wells (MW-9 and MW-10) to assess the lateral extent of petroleum hydrocarbon impact southwest of the site. These monitoring wells were developed on May 16, 2000. Stratus also supervised the installation of one air sparge well (AS-1) in the vicinity of the active pump islands. Monitoring well MW-5, located in the shoulder of Lower Sacramento Road, was destroyed on May 5, 2000. The City of Lodi requested the abandonment of well MW-5 due to a proposed widening of Lower Sacramento Road. All existing monitoring wells (with the exception of MW-7) and the newly installed MW-9 and MW-10 were surveyed on August 4, 2000 by Morrow Surveying, Inc. The location of the wells is shown on Figure 2. During the resurvey MW-7 was not located. Stratus oversaw the construction and installation of a SVES in July and August 2000. A system startup and source test was conducted on August 15, 2000. The results of the startup and source test were reported to San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD) on October 19, 2000. GROUNDWATER GRADIENT AND DIRECTION The second quarter 2001 groundwater monitoring event was conducted on May 22, 2001. The activities consisted of measuring groundwater levels, purging the groundwater monitoring wells, and collecting groundwater samples for chemical analysis. Groundwater levels were measured using an electronic sounding device and recorded on the field data form presented in Appendix A. Table 1 presents the historical and second quarter 2001 groundwater elevation data. Field sampling procedures are presented in Appendix B. At the time of the second quarter monitoring event, groundwater was encountered at depths ranging from 36.05 to 42.13 feet below ground surface (bgs). The measured water levels were corrected to mean sea level (MSL) and used to plot a groundwater elevation contour map. Figure 2 presents groundwater elevations and contours for the second quarter 2001 monitoring event. Groundwater elevations onsite appear to be affected by soil vapor extraction. South of the site, the direction of groundwater flow was calculated to be towards the south- southeast with an average gradient of 0.0025 ft./ft.. Groundwater elevations decreased by approximately 1.0 foot in all monitoring wells except at MW-8 and S-2. Due to soil vapor extraction, groundwater is mounding in MW-8 and S-2 resulting in an inward flow • towards MW-8. CAProject Files\USA Gaso1ine%00651Qtr1y1USA 0065 2Q01 Report.doc 5rRAruS