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Consolidated Forward Inc. Landfill Page 15 The appropriate responsible agencies, the CIWMB and RWQCB, shall conduct a review of the liner and leachate collection system for the vertical expansion over the existing landfill(s) proposed in the JTD. 49 (F.6) Proposed as Part of the Project: Because of the potential for contamination from WMU B and/or A of the shallow groundwater table dow-ngradient and adjacent to the project, existing domestic off-site wells within 500 feet of the eastern property boundary will be sampled at the same frequency as the monitoring wells onsite and for the same constituents (see CCR, Title 27). Final determination of the sampling program and the 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 This ETR: Water quality at the offsite wells, such as the two private wells along Austin Road and the CYA wells, shall be monitored at least biannually (twice a year) to determine the extent that the plume impacts them Continued operation of the groundwater extraction system at the site will help limit the contaminant plume from expanding in a downgradient direction but will not address the offsite 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 (20O lb) Alternative 3 proposal. However, in their revised AEE (2002x) report the proposed alternative 11 is put forth as the only remedy to implement at this time. The RWQCB accepted alternative 11 in their letter to Forward dated March 11, 2002. AdOL If the groundwater VOC concentrations do not attenuate at a rate that is acceptable to the RWQCB then the Board will require that Alternative 3 - or some variant on Alternative 3 - be implemented. The recent (AEE, 2002a) addendum to the corrective action proposed procedures to analyze the hydrochemcial trends and trigger concentrations at which additional extraction wells would be considered. (Atkinson, 2002). 50 (F.7) Identified in This EER: Two infiltration methods are currently used at the landfill. Most of the groundwater currently pumped by the former agriculal well is used onsite; thus, some of it will infiltrate through tur 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 discharged into Littlejohn Creek currently, which both recharges aquifers below and moves offsite. Treated groundwater from the groundwater extraction system is proposed to be infiltrated back to the aquifer through an infiltration basin (AEE, 200113, 2002a) located near well MW -11. The infiltration basin would improve recharge to the local aquifer and is also designed to create a hydraulic barrier to inhibit further northward migration of the groundwater plume. The RWQCB letter to Forward dated March 11, 2002 agreed to allow for their recharge remedy (Almmative 11) to go forward without Alternative 3 (extended pumping) while quarterly monitoring at the groundwater wells occurs. If the groundwater VOC concentrations do not attenuate at a rate that is acceptable to the RNVQCB then the Board will require that Alternative 3, or some variant on Alternative 3, be implemented. The recent (AEE, 2002a) addendum to the corrective action proposed procedures to analyze the hydrochemical trends and trier concentrations at which additional extraction wells Would be considered. (Atkinson, 2002).