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Monitoring—July 14-15,2006, 7500 West Eleventh Street, Tracy,CA. Page 2 Report:Groundwater-quality g Y The restaurant on the property remained in operation until it was damaged by fire in June � 2003, but it was restored and, by June 2004, it had reopened for business. The restaurant is leased from the Navarras by Able Manzilla Mendoza and Guadeloupe Contrecias, et ux, (the Mendozas) who do business as the Casa Mendoza restaurant. In 2000, the Mendozas leased the rest of the site. In early 2006, the Mendozas subleased a portion of the site in its northwestern corner (see Figure 2 for location) to Arch Lumber, Inc., which uses it as a lumber storage yard. The fueling station that had been located on the site ceased operation in 1998 and on December 9 of that year, four registered underground fuel storage tanks, ranging in size from 3,500-gal. to 10,000-gal., that had been in use at the station in 1998 were removed from the property under the permit and oversight of the SJCEHD (Dietz Irrigation 1999a). Those tanks were located, as is shown on Figure 2, in the northeastern corner of the site. A total of 6,000 linear feet of associated piping were also removed from the property. As the piping was being removed, four additional 1,000-gal, underground fuel storage tanks, the presence of which was previously unknown, were encountered. These very old (circa 1930) tanks were found to be in a very deteriorated condition, but empty and dry. As is shown on Figure 2, the old, abandoned fuel tanks were located a short distance to the west of the modern tanks. When the tanks were removed, there was no evidence that they had leaked. However, when the four modern tanks were removed from the tank pit, the resultant fall in the elevation of the water table induced floating product that originated beneath the pump islands to flow into the pit. It was found that fuel hydrocarbons had leaked from underground piping beneath the fuel pump islands of the former fueling station. The former locations of the fuel pump islands are shown on Figure 2. Some 2,000 gallons of that floating product and affected groundwater were removed from the subsurface by pumping from the tank pit into a vacuum truck, which was used to transport it to a permitted recycling facility (Dietz Irrigation 1999a). In addition, 521.25 tons of soil heavily affected by fuel hydrocarbons were excavated from beneath the pump islands and disposed off-site at a permitted facility. 1.4 Site Characterization Studies An initial site characterization investigation was completed in May 2000 that included drilling 14 soil borings, installation of seven groundwater-quality monitoring wells (Nos. MW-1 through MW-7) and identification of potable water supply wells in the neighborhood of the Navarra Site (The San Joaquin Company 2001). See Figure 2 for locations of the monitoring and water supply wells. A second phase of site characterization was conducted in March and April 2002, during which eight additional groundwater-quality monitoring wells, numbered MW-3A, MW-313, MW-8 through MW-12, and MW-12A were installed (The San Joaquin Company 2002). A third phase of site characterization was conducted in April 2004, during which seven additional groundwater-quality monitoring wells, numbered MW-13 through MW-19, and five floating product monitoring wells (MWFP-1 through MWFP-5) were installed (The San i Joaquin Company 2004). A total of 22 groundwater-quality and five floating product sic