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• Water Quality Monitoring Report Forward Landfill groundwater (and lysimeter samples) at the Forward Unit are most likely due to landfill gas from unlined unit WMU-B. Forward has continued to minimize gas related impacts to groundwater by preventing ponding of water through regular site maintenance. Furthermore, in accordance with CCR Title 27, Section 20937, Forward continues to install additional landfill gas extraction wells, as needed. Concentration Limit Thresholds In accordance with RWQCB Order No. 115-2014-0006, the routine inorganic monitoring data obtained from the Forward Unit during the first quarter 2014 monitoring period were compared to intrawell concentration limits (CLs) established for each well. Since the new WDR requires annual updates to the CLs and CL have not been updated since 2011, inorganic CLs for the Forward Unit wells were recalculated and are presented in Table 2-4. Details on the CL update are presented in Appendix D. As summarized in Table 2-4, the following CLs were exceeded during the first quarter 2014 monitoring period. Nitrate -N at well MW -14 • Sulfate at well MW -24 Trend analyses were performed for wells and constituents that exceeded respective CLs. However, no statistically significant increasing temporal trends were identified for either of the inorganic constituents that exceeded a CL. Trend analyses are included in Appendix D. The inorganic CL exceedance for nitrate as nitrogen in well MW -14 is believed to be related to the groundwater gradient reversal in the northeast corner of the landfill and well MW -24 is a background well, so the CL exceedance for sulfate is attributed to background conditions. Since both CL exceedances are not believed to be related to a release from the landfill and in the absence of VOCs at these wells, no further action is recommended at this time. 2.1.5 Vadose Zone Monito The current vadose-zone monitoring network at the Forward Unit consists of 10 lysimeters. The lysimeter locations are shown on Figure 2-1. As recorded in the field notes for lysimeters (Appendix C) and summarized on Table 2-5, lysimeters were reported dry, and as a result, no soil -pore liquid samples were collected during the current monitoring period. Of note, there was no access port to inspect pan lysimeters WMW-D01N, WMW-D01S, and WMW-D02. GLA and Forward are currently preparing a status report for the unsaturated zone monitoring system that will include a workplan to evaluate restoration of the vadose zone monitoring points. M:\ 2014.0012\FA_1Q14.docx 7 4/28/2014, Rev. 0