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Draft Environmental Impact Report Page 111-21 P P g Forward Inc. Landfill Expansion The expansion of the disposal area and lowering of the base level of the northeast area of the landfill would increase total landfill capacity by approximately 43.4 million cubic yards beyond . ` currently permitted levels,which would allow disposal at the landfill to continue until 2034. Most site operations would remain as described for the existing Forward Landfill, above. The environmental monitoring and control systems described above would be extended to the proposed expansion area. The proposed physical and operational changes are described below. .. Expand the Landfill Footprint The proposed lateral expansion of the landfill would increase the disposal footprint from approximately 355 acres to 552 acres and increase the total permitted area of the site from 567 to 751 acres. The proposed expansion area is primarily located south and west of the current permitted landfill areas(185 acres), and also includes two areas within the currently permitted landfill:approximately 11 acres along the existing alignment of the South Branch of the South Fork of Littlejohn Creek,and approximately 10 acres in the northeast corner of the site(see sub-area F in Figure III.0-3). The maximum elevation of refuse fill in the expansion area would be approximately 183 feet above mean sea level(MSL), lower than the permitted maximum height of 210 feet MSL for the existing Forward Landfill (see Figures IILC-5 and III.0-6). The expansion area would have a base liner and Leachate Collection and Recovery System (LCRS), with a design utilizing two configurations, described above,to account for the two types of liner gradients that would be constructed;base grades and side slopes. Forward's WDRs also require a minimum five-foot separation between wastes or leachates and the highest anticipated elevation of underlying groundwater,including the capillary fringe. Current typical groundwater levels at the landfill are approximately 15 to 30 feet below mean sea level (MSL). However,the maximum high groundwater elevation underlying the proposed expansion area is minus two feet MSL west and south of the existing landfill,and minus six feet MSL in the area east of WMU FU-06 (see Figure III.C-3). In the event that historic high groundwater levels occur and the required five-foot separation between historic high groundwater and waste cannot be maintained, an engineered alternative liner system is proposed for those areas where waste would be discharged at or below an elevation five feet above estimated maximum high groundwater. This system would include a subdrain system installed below the waste containment system(liner),and an additional foot or operations layer soil installed above the liner. The projected total remaining airspace for the Forward Landfill,as of December 2008,was approximately 25.1 million cubic yards(mcy). The proposed expansion would add approximately j 43.4 mcy of airspace,which would allow disposal at the Forward Landfill to extend to 2034. This capacity is measured as total air space;the actual fill space would be less because some of the air space would be occupied by daily cover,liner,LCRS,etc. (In addition, as discussed in Lower the Base Level of the Northeast Area,below,lowering the base grade of the northeast area would increase airspace by 840,000 cubic yards,equivalent to less than one year of disposal.) C-11 Relocate South Branch of the South Fork of Littlejohn Creek To allow create a contiguous disposal area,a 3,200-foot reach of the South Branch of the South Fork of Littlejohns Creek would be relocated to the eastern and southern boundaries of the landfill (see Figure III.0-6). The creek relocation is intended to: (1)provide riparian habitat restoration/creation, (2) provide adequate flood control(i.e.,to have capacity to carry the 100-year