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Draft Supplemental Environmental Impact Report Page VIII-61 Forward Inc.Landfill 2018 Expansion Project leachate accumulation over the low permeability elements of the liner system,and a pan lysimeter system beneath the sump (i.e.low point)of the composite liner system would allow for continuous monitoring of the composite liner system performance. �! The system described above is known as a "Subtitle D liner and LCRS",as it conforms with the federal regulations for municipal solid waste landfill (MSWLF) liners promulgated in 40 CFR 258 Subtitle D.The federal Subtitle D liner system was developed to establish minimum national criteria for all MSWLFs to"ensure the protection of human health and the environment." Extensive research was performed by the EPA to develop the prescriptive Subtitle D liner system, as detailed in the Solid Waste Disposal Facility Criteria,Technical Manual (EPA,April 1998 Revision;Original November 1993)and as discussed in the Preamble to the promulgation of the 40 CFR 258 regulations(Federal Register,Vol. 56, No. 196, Rules and Regulations,October 9, 1991). As detailed in the EPA Technical Manual, "the composite liner system is an effective hydraulic barrier because it combines the complementary properties of two different materials into one system: 1) compacted soil with a low hydraulic conductivity;and 2) an FML(FMLs are also referred to as geomembranes)." Subtitle D Liners have been used effectively in MSWLFs for over the last quarter century throughout the United States.An extensive study of the field performance of Subtitle D lined landfills was conducted by the USEPA for landfills throughout the US (Assessment and Recommendation for Improving the performance of Waste Containment Systems, USEPA/600/R-02/099;Bonaparte,Daniels,and Koerner,2002)that identified only one Subtitle D lined facility where groundwater or surface water was impacted. The impact was due to landfill gas migrating beyond the edge of the liner system and to groundwater. The landfill gas extraction system and the liner termination at the Forward landfill have been designed to prevent this occurrence. In September 2002,Forward submitted a site-specific analysis of the effectiveness of the prescriptive Subtitle D liner in preventing leakage at the Forward Landfill (Performance Demonstration for a Single Composite Liner, Forward Landfill; GLA 2002)to comply with a Central Valley Regional Water Quality Control Board (CVRWQCB)resolution for all landfills within its region(Resolution No. 5-00-213, September 15,2000).The document concluded that studies that were performed for this project demonstrate that landfill leachate will not impact groundwater at the Forward Landfill" using the Subtitle D system. The study included fate and transport analyses that"indicate that leachate leakage would have an insignificant(essentially undetectable) effect on groundwater quality beneath the site."This document was reviewed and approved by the RWQCB and used in establishing Waste Discharge Requirements (WDRs)for the site. In addition to building WMUs at Forward with the prescriptive Subtitle D system, Forward implements extensive third-party construction quality assurance(CQA) during construction of the liner and LCRS components.The CQA includes compliance with numerous testing requirements, including permeability tests of the clay liner component and electric leak detection tests of the geomembrane to ensure that no holes are present. When the geomembrane is installed, and following placement of the overlying LCRS r