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6.0 ANNUAL SUMMARY 6.1 GENERAL During the 2012 monitoring year, groundwater elevation measurements were performed quarterly and water quality sampling and soil-pore gas monitoring were performed semiannually in accordance with WDR Order No. R5-2007-0046. All of the monitoring points were 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 2012, hydrographs illustrating the historic groundwater elevations of the detection monitoring wells, and information relative to well screen elevations and pump intake elevations are included in Appendix D. Discussions of the historical trends in constituent concentrations are presented in Section 4. 6.2 GROUNDWATER Over the 2012 monitoring year, groundwater elevations varied by about one to two feet with a gradient between 0.001 to 0.004 ft/ft to the south to southeast. Groundwater quality conditions beneath the French Camp Landfill during the 2012 monitoring year are generally similar to those observed over the previous years. Excluding field parameters, CLs were exceeded for chloride at wells MW-9A and MW-10A; for TDS at well MW-10A; and for TCFM at well MW-9A during both semiannual monitoring events in 2012. Additionally,the CL for chloroform was exceeded in well MW-6A during the first semiannual 2012 monitoring period. Statistically significant increasing trends were consistently noted for potassium and sulfate at well MW-9B and for chloride at well MW-10A,while decreasing trends were consistently noted for chloride, specific conductance, and TDS at well MW-7A; for bicarbonate, chloride, nitrate, and TDS at well MW-8A; for nitrate and TCFM at well MW-9A; and for nitrate at well MW-10A. With the exception of the consistent detection of TCFM at well MW-9A and the detection of chloroform during the first semiannual monitoring period at well MW-6A, no VOCs were detected in groundwater samples collected during the 2012 monitoring year. 6.3 SURFACE WATER Surface water elevations at the stream gauging stations varied by approximately two feet during the 2012 monitoring year. These changes reflect seasonal precipitation patterns. Surface water generally flows west toward the San Francisco Bay. c:\zoia-027\Fczsntz.aoc 6Geo-Logic Associates