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NrCLEARWATER <br /> G R 0 U, 1' <br /> C„,,,;,,,_ Envi ron mentcf SeYvrces <br /> three wells, and with approval from the SJCEHD, analysis for TPHd has been discontinued. <br /> Results of these efforts were presented in Clearwater's Subsurface Investigation Report, dated <br /> November 20, 1997. <br /> __'j <br /> Based on these initial investigation results, the SJCEHD requested monitoring wells be installed <br /> ! to better define the aerial extent of soil and groundwater contamination. After discussion with <br /> Lori Duncan of the SJCEHD, Clearwater submitted the Workplan for Site Investigation dated <br /> November 18, 1998. An addendum to the workplan, dated December 10, 1998 was submitted in <br /> response to SJCEHD comments. The workplan and addendum were approved by the SJCEHD <br /> on December 15, 1998. <br /> In January 1999, Clearwater supervised the installation of three additional groundwater <br /> monitoring wells (MW-4 through MW-6) to delineate the extent of dissolved-phase <br /> contamination. The results of the investigation indicated that the extent of sorbed-phase <br /> contamination was delineated and existed from approximately 10 to 25 feet bgs near the former <br /> USTs. Results of the groundwater sample analyses indicated that the extent of dissolved-phase <br /> contamination remained undelineated downgradient from the former UST system. However, <br /> high contaminant concentrations in wells located in cross-gradient positions from the former <br /> USTs suggested that off-site sources may be contributing to contamination detected beneath the <br /> site. Initial inquiries suggested, and it was later confirmed, that there is an existing fuel transport <br /> line in the area of the site, and that it is currently filled with nitrogen gas. Based on this <br /> .`i information, Clearwater recommended additional investigation along South Fresno Avenue to <br /> better understand the distribution of contamination and possible contribution from potential off- <br /> site sources. The results of this phase of investigation were presented in Clearwater's Well <br /> Installation and Groundwater Monitoring Report- First Quarter 1999. <br /> ___ On March 8, 2000, Clearwater supervised the completion of one hydropunch, six soil borings, <br /> the, destruction of MWS, and constructed three additional wells: MW-SB, MW-7, and MW-8 <br /> >” (Figure 2). All three wells were placed on the downgradient portion of the plume to help <br /> � ZB178E iSOC System Installation/Start-up 3 Nov.24,2004 <br />