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►.. Work Plan for Refined Plume Definition and Management of Floating Product-7500 W J 1 th St, Tracy, CA. Page 8 ,t groundwater-quality monitoring at the 7500 West Eleventh Street was conducted in November 2000 (The San Joaquin Company 2001f). Monitoring of the seven wells then extant at the site was continued on a quarterly basis until April 11, 2002 (The San Joaquin «. Company 2001d, 2001c, 2002d). The records of groundwater elevations and concentrations of analyses of concern measured in samples of groundwater recovered from the seven monitoring wells are compiled in Tables 1 and 2, respectively. 4.3 Extended Site Characterization ti- In July 2001, the SJCEHD directed that site characterization work at the Navarra Site be extended to better define the characteristics of the zone of the subsurface beneath and down- gradient from the Navarra Site that had been affected by the release of hydrocarbons (San �. Joaquin County Environmental Health Department 2001b). During discussions with SJC about the scope of the proposed extension of the site characterization program, SJCEHD directed that, inter alia, additional groundwater-quality monitoring wells that penetrate through the clay aquitard that separates and protects the shallow aquifer from the deeper aquifers beneath the Navarra property be included in the "- scope of that work. At that time, SJC's California-licensed engineer in responsible charge of the site characterization program expressed serious concern that installation of wells that penetrated the first aquitard beneath the site would pose a significant risk to the quality of the water in the deeper aquifers. However, the SJCEHD staff insisted that those wells be installed. After the Navarras overcame some difficulties in obtaining timely payment from the USTCF for the initial site characterization work performed in 1999 and 2000 that had been pre- approved by that Fund, SJC was able, in October 2001, to submit a work plan for an extended site characterization program. The work plan provided for the deep wells that penetrated through the protective aquitards as directed by the SJCEHD and proposed additional wells to explore the extent of the plume of affected groundwater that was migrating to the north of West Eleventh Street and along and to the east of Chrisman Road (The San Joaquin Company 2001c). The locations of the proposed wells were similar to those originally proposed for those areas, the authorization po"I and funding for which had been denied at the time SJC's original site characterization work s,.' plan was submitted to the SJCEHD and the USTCF in June 1999. ,x. Based on the work plan for the extended site characterization, which included the elements directed by the SJCEHD, eight additional groundwater quality monitoring wells - MW-8 through MW-12 and MW-3A, MW-3B and MW-12A - were installed at the site. The work was completed in April 2002 (The San Joaquin Company 2002c). 4.4 Extended Quarterly Groundwater-quality Monitoring Program On April 11, 2002, the scope of the groundwater-quality monitoring program was expanded to include quarterly recovery of samples from each of the 15 monitoring wells extant on the sic