ARCHIVED REPORTS_JULY 2014 FINAL TPR

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'-' A, the DTSC). These agencies keep abreast of state-of-the-art information on leachate generation mechanisms and appropriate mitigation. If, in the future, monitoring demonstrates that the procedures above were insufficient to mitigate the effects of landfill-generated leachate, the agencies will, as appropriate, require addttional mitigation measures. f. 48 (F.5) Proposed as Part of the Project: Maximum pre-loaded settlement of the combined landfill is projected in the JTD to provide, the maximum period for settlement, and take advantage of anticipated improvements in geosynthetic technology. Future design for the vertical expansion will, if necessary, include additional components in the liner system, depending on future differential settlement on the liner system. The extraction wells proposed as part of the Revised Engineering Feasibiltty Study (AEE, 2001 B) will be maintained and monitored during combined landfill build-ou1 phases, and modified as needed based on the RWQCB's review of monitoring data. The approprfate responsible agencies, the CIWMB and RWQCB, shall conduct a review of the liner and leachate colleclion system for the vertical expansion over the existing landfill(s) proposed in the JTD. g. 49 (F.S) Proposed as Part of the Project: Because of the potential for contamination from WMU B and/or A of the shallow groundwater table downgradient and adjacent to the project, existing domestic off-site wells within 500 feet of the eastem property boundary will be sampled at the same frequency as the monttoring wells onsile and for the same constituents (see CCR, Title 27). Final determination of the sampling program andthe evaluation of the test results, along with the appropriate mitigation, is the responsibility of the RWQCB and must be carried out under their permit authorization. Identified in EIR: Water qualtty at the offstte wells, such as the two private wells along Austin Road and the CYA wells, shall be monitored at least biannually (twlce a year) to determine the extent that the plume impacts them. Continued operation of the groundwater extraction system at the site will help limtt the contaminant plume from expanding in a downgraaJent direction but will not address the offstte component far beyond the boundary of Austin Road Landfill unless the contamination is attenuated and diluted over time or more extraction wells are brought on line per the AEE (2001 b) Altematlve 3 proposal. However, in their revised AEE (2002a) report the proposed altemative 11 is put forth as the only remedy to implement at this time. The ' RWQCB accepted altemative 11 in their letter to Forward dated March 11, 2002. I{the groundwater VOC concentrations do not attenuate at a rate that is acceptable to the RWQCB then the Board will require that Altemative 3 -or some variant on Altemative 3 -be implemented. The recent (AEE, 2002a) addendum to the corrective action proposed procedures to analyze the hydrochemcial trends and trigger concentrations at whicih addttional extraction wells would be considered. (Atkinson, 2002). h. 50 (F.7) Identified in EIR: Two infitlration methods are currently used at the landfill. Most of the groundwater currently pumped by the former agricultural well is used onstte; thus, some of it will infiltrate through the unlined parts of the site and migrate back to the groundwater aquifer from where it was extracted. Secondly, the treated groundwater from the groundwater extraction syStem is San Joaq uin County Community Development UP-00-7, ER-00-21F0rward, Inc. Page 16