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6.0 ANNUAL SUMMARY 6.1 GENERAL During the 2011 monitoring year, groundwater elevation measurements were performed quarterly and water quality monitoring points and soil-pore gas probes were sampled semiannually in accordance with WDR Order No. R5-2007-0046. All of the monitoring points are sampled for the monitoring parameters summarized in Table 1. Time-series plots depicting groundwater and surface water constituent concentrations and a tabular summary of the historical monitoring data are presented in Appendix D and in an electronic format in Appendix C. Piper diagrams of the semiannual data obtained in 2011 are included in Appendix D, and hydrographs of the detection monitoring wells, illustrating historic groundwater elevations, well screen elevations, and pump intake elevations are also included in Appendix D. Discussions of the historical trends in constituent concentrations are presented in Section 4. 6.2 GROUNDWATER Groundwater elevations have remained relatively static over the past year, reflecting seasonal precipitation patterns. During the first semiannual 2011 monitoring period, groundwater was interpreted to flow east to northeast at a gradient of 0.001 to 0.005 ft/ft. During the second semiannual 2011 monitoring period, groundwater was interpreted to flow to the south at a gradient of 0.002 to 0.005 ft/ft. Groundwater quality conditions beneath the French Camp Landfill during the 2011 monitoring year are generally similar to those observed in the previous monitoring year. Excluding field parameters, inorganic CLs were only exceeded in wells MW-9B and MW-I OA during the monitoring year. Furthermore, statistically significant increasing trends were consistently noted for chloride in well MW-10A, and potassium and sulfate in well MW-9B. Decreasing trends were consistently noted for calcium, magnesium, and pH in wells MW-6A; chloride, specific conductance, and TDS in well MW-7A; bicarbonate,magnesium, nitrate as nitrogen, and TDS in well MW-8A; pH in well MW-9B; and nitrate as nitrogen in well MW-I OA. No VOCs were detected in groundwater monitoring wells at the French Camp Landfill during the first semiannual 2011 monitoring period. During the second semiannual 2011 monitoring period, chloroform and TCFM were measured above the PQL in the samples collected from wells MW-6A and MW-9A, respectively. A discussion of these VOC detections is presented in Section 4.4. 6.3 SURFACE-WATER Surface-water elevations at the stream gauging stations have remained relatively static over the past year, generally reflecting precipitation patterns. Surface-water generally flows west toward the San Francisco Bay. C:\2011-0051\FC_2SABt.doc 6 Geo-Logic Associates