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Consolidated Forward Inc. Landfill Page 15 <br />49 (F.6) <br />The appropriate responsible agencies, the CIWMB and RWQCB, shall conduct a re\;ew of <br />the liner and leachate collection system for the vertical expansion over the existing landfill(s) <br />proposed in the JTD. <br />Proposed as Part of the Project: <br />Because of the potential for contanrination from WMU B and/or A of the shallo\v <br />grOlmdwater table dov;ngradient and adjacent to the project, existing domestic off-site wells <br />within 500 feet of the eastern property boundary will be sampled at the same frequency as the <br />monitoring wells onsite and for the same constituents (see CCR, Title 27). Final <br />determination of the sampling program and the evaluation of the test results, along \\ith the <br />appropriate mitigation, is the responsibility of the RWQCB and must be camed out under <br />their permit authorization. <br />Identified in Tbls EIR: <br />50 (F.7) <br />Water quality at the offsite wells, such as the two private'wells along Austin Road and the <br />CYA wells, shall be monitored at least biannually (twice a year) to determine the extent that <br />the plume impacts them. Continued operation of the groundwater extraction system at the <br />site will help limit the contaminant plume from expanding in a downgradient direction but <br />will not address the offsite component far beyond the boundary of Austin Road Landfill <br />unless the contamination is attenuated and diluted over time or more extraction wells are <br />brought on line per the AEE (200 I b) Alternative 3 proposal. However, in their revised AEE <br />(2002a) report the proposed alternative II is put forth as the only remedy to implement at this <br />time. The RWQCB accepted alternative II in their letter to Forward dated March 11,2002. <br />If the groundwater VOC concentrations do not attenuate at a rate that is acceptable to the <br />RWQCB then the Board will require that Alternative 3 -or some variant on Alternative 3 -be <br />implemented. The recent (An, 2002a) addendum to the corrective action proposed <br />procedures to analyze the hydrochemcial trends and trigger concentrations at which <br />additional extraction wells would be considered. (Atkinson, 2002). <br />Identified in This EIR: <br />Two infiltration methods are =t1y used at the landfill. Most of the groundwater currently <br />pumped by the former agricu1tural well is used onsite; thus, some of it will infiltrate through <br />the unlined parts of the site and migrate back to the groundwater aquifer from where it was <br />extracted. Secondly, the treated groundwater from the groundwater extraction system is <br />discharged into Littlej ohns Creek: currently, which both recharges aquifers below and moves <br />offsite. <br />Treated groundwater from the groundwater extraction system is proposed to be infiltrated <br />back to the aquifer through an infiltration basin (AEE, 200IB, 2002a) located near well <br />MW -11. The infiltration basin would improve recharge to the local aquifer and is also <br />designed to create a hydraulic barrier to inhibit further northward migration of the <br />groundwater plume. The RWQCB letter to Forward dated March II, 2002 agreed to allow <br />for their recharge remedy (Alternative II) to go forward without Alternative 3 (extended <br />pumping) while quarterly monitoring at the groundwater wells occurs. If the groundwater <br />VOC concentrations do not att.enuate at a rate that is acceptable to the RWQCB then the <br />Board will requir~ that Alternatiye 3, or some variant on Altemative 3, be implemented. The <br />recent (AEE, 2002a) addendum to the corrective action proposed procedures to analyze the <br />hydrochemical trends and trigger concentrations at which additional extraction wells would <br />be considered. (Atkinson, 2002).