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FORWARD LANDFILL 9999 S.Austin Road Manteca,CA 95336 (209)982-4298,Fax(209)982-1009 July 18, 2017 JN: SO17.1030 Mr. Brendan Kenny Central Valley Regional Water Quality Control Board 11020 Sun Center Drive,#200 Rancho Cordova, CA 95670-6114 SUBJECT: JANUARY—JUNE 2017 SEMIANNUAL WATER QUALITY MONITORING REPORT FRENCH CAMP LANDFILL SAN JOAQUIN COUNTY,CALIFORNIA Forward, Inc. (Forward) is pleased to submit the January through June 2017 semiannual monitoring report for the French Camp Landfill, in compliance with the California Regional Water Quality Control Board - Central Valley Region (RWQCB) Waste Discharge Requirement (WDR) Order Number R5-2007-0046. This report summarizes standard observations and presents the results of surface-water, groundwater, and soil-pore gas monitoring from the semiannual (January 1 through June 30, 2017) monitoring period. During the monitoring period, groundwater quality conditions beneath the French Camp Landfill during the monitoring period are generally similar to those observed during previous monitoring periods. During the semiannual monitoring period, an inorganic concentration limit (CL) was exceeded for chloride in the samples from wells MW-913 and MW-10A. However, no statistically significant increasing trends are associated with these exceedances. Previously, a No Release Demonstration (NRD) was performed for CL exceedances of chloride and total dissolved solids (TDS) at the site (Herst, 2005). The NRD concluded that French Camp Landfill, located within the central Stockton area, has been impacted by saltwater intrusion and the elevated chloride and TDS concentrations measured in groundwater monitoring wells are believed to be the result of this condition and not the result of landfill-related impacts. With the exception of the detection of trichlorofluoromethane (TCFM) at well MW-9A and chloroform at well MW-6A, no volatile organic compounds (VOCs) were detected during the monitoring period. Both TCFM and chloroform have been previously confirmed in retest samples, however, neither of these VOCs exhibited an increasing trend. Given the distance of well MW-6A from the landfill, the chloroform concentrations measured in well MW-6A is not believed to be the result of a release from the landfill, while the TCFM concentrations measured in well MW-9A are well below risk-based concentrations and have been attributed to landfill gas following construction of the final cover system.