ARCHIVED REPORTS_GROUNDWATER MONITORING AND REMEDIATION REPORT - 3RD AND 4TH QUARTERS 2011

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CRA prepared a vicinity map (Figure 1) and groundwater contour and chemical concentration maps (Figures 2 and 3). CRA presents the sampling schedule and analyses in Table 1, the well construction details in Table 2, and groundwater monitoring data in Table 3. Blaine's field notes are presented in Appendix A, and the laboratory reports are presented in Appendix B. 2.2 REMEDIATION 2.2.1 GROUNDWATER EXTRACTION (GWE) SYSTEM OPERATION The temporary GWE system began operating on April 10, 2006. The GWE system pumps groundwater from well MW-1 using a top-loading submersible pneumatic pump. Groundwater is stored in an on-site baker tank, and vacuum trucks transport the water to Shell's Martinez Refinery for recycling. Mass removal and groundwater analytical data are presented in Table 4. Note that this table includes cumulative volume and petroleum mass removed from prior pumping operations. 2.2.2 AIR SPARGE (AS) AND SOIL VAPOR EXTRACTION (SVE) IMPLEMENTATION CRA submitted requests for bids for system installation during the third quarter 2011 and reviewed the bids during the fourth quarter 2011. As discussed in our November 30, 2011 letter to Central Valley Water Board, we recommend reevaluating risk and remedial alternatives for the site. 3.0 CURRENT FINDINGS The monitoring data discussed include groundwater elevations and flow directions, vertical gradients, separate-phase hydrocarbons (SPHs), isoconcentration maps, and petroleum constituent concentrations and plume trends. The remedial system data discussed include system performance,operation, and effectiveness. 3.1 GROUNDWATER ELEVATIONS AND FLOW DIRECTIONS The groundwater contour maps for the third and fourth quarters of 2011 are presented as Figures 2 and 3, respectively. The groundwater flow directions and hydraulic gradients near the truck loading rack and well MW-10 are presented on Table 5. 241729(32) 2 CONESTOGA-ROVERS&ASSOCIATES