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upstream of the landfill within the Walker and French Camp Sloughs (respectively) and are used as background sampling points. Station SW-3 is located downstream of the landfill at the confluence of the two sloughs. A comparison of upgradient(SW-1 and SW-2)to downgradient(SW-3) surface water samples indicates generally similar inorganic constituent concentrations.With the exception of an estimated trace-level detection of toluene in upstream station SW-1,no VOCs were detected in the surface water monitoring stations, suggesting that the landfill is not impacting surface water quality. As presented in Table 4, the retest sample collected for cyanide in well SW-3 did not confirm the presence of cyanide as a new constituent of concern and no further action is necessary. Stream gauging was performed on August 5 and November 29, 2013, at monitoring points SG-1 and SG-2 and the data is summarized in Table 5. As shown in Figures 1 and 2, monitoring point SG-1 is located upgradient in the Walker Slough and monitoring point SG-2 is located upgradient in the French Camp Slough. 5.0 SOIL-PORE GAS MONITORING In accordance with WDR Order No. R5-2007-0046, soil-pore gas probes are monitored semiannually using a field screening protocol, and soil-pore gas samples are only collected if field screening indicates methane concentrations greater than 2.5 percent. During the monitoring period, field screening of soil-pore gas probes was conducted on August 6, 2013. As shown on Table 6, methane was not detected in any of the soil-pore gas probes, and as a result, no samples were collected. 6.0 ANNUAL SUMMARY 6.1 GENERAL During the 2013 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 are presented in Appendix D and a tabular summary of the historical monitoring data is presented in an electronic format in Appendix C. Stiff diagrams of the semiannual data obtained in 2013, hydrographs illustrating the historical groundwater elevations of the detection monitoring wells, and information relative to well screen elevations and pump intake elevations are included in Appendix D. 6.2 GROUNDWATER Over the 2013 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. C:\2013A02MC2SA13.doc 5 Geo-Logic Associates