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Draft Supplemental Environmental Impact Report Page III-35 Forward Inc.Landfill 2018 Expansion Project implementing advisories as detailed in Table 3A of the San Joaquin County Airport Land Use Compatibility Plan.) The acreage added in the south area would be gained by shifting the existing disposal footprint north and realigning the creek to the southern and eastern boundaries of the site. The acreage added in the northern area was formerly part of the 100-year flood plain for the North Fork of South LittleJohns Creek and was not permitted for waste disposal;however,after the North Fork of the creek was realigned,this area is no longer in the 100-year floodplain and can be developed as landfill. The maximum elevation of refuse fill in the additional development areas would be approximately 190 feet above mean sea level(MSL), lower than the permitted maximum height of 210 feet MSL for the existing Forward Landfill. The footprint of the refuse fill would be set back a minimum of 100 feet from the east property boundary. The additional development areas would have a base liner and Leachate Collection and Recovery System(LCRS)consistent with currently constructed modules and in compliance with pertinent regulatory requirements. The proposed landfill expansion refuse fill grades meet both State and Federal regulatory criteria under both static and seismic conditions.14 The Title 27 regulations governing landfills and Forward's WDRs require a minimum five-foot separation between wastes or leachates and the highest anticipated elevation of underlying groundwater(including the capillary fringe)or the installation of an engineered alternative,such as a subdrain. The regional groundwater in the greater Stockton area,including the vicinity of the Forward Landfill,has been overdrawn for many years and has shown a clear pattern of decreasing groundwater levels. Current groundwater levels at the landfill are approximately 14 to 30 feet below mean sea level (MSL). Based on a review of historic groundwater records,the maximum high groundwater elevation underlying the southern and northeastern development area is approximately four feet and ten feet below MSL,respectively. The minimum base grades for the proposed landfill development area have been developed to provide for the required 5-foot separation between historic high groundwater and refuse. The projected total remaining airspace for the Forward Landfill,as of January 2018,was approximately 15.7 million cubic yards(mcy). The proposed expansion would add approximately 8.12 mcy of disposal airspace,which would allow disposal at the Forward Landfill to extend to 2036,from the current anticipated closure date of 2030. While all of the proposed expansion would be Class II landfill space,it is anticipated that Class III waste would be disposed in the expansion areas along with Class II waste. The proposed 2018 Expansion Project would add 8.12 million cy of landfill capacity,compared to the 32 million cy in the previously proposed(2013)project. The projected landfill closure date under the 2018 Expansion Project is 2036,compared to 203915 for the previously proposed project. The 2018 Expansion Project would not entail putrescible waste (waste streams other than concrete,rock, asphalt,wood and yard waste) in the Outer Approach of the Stockton la GLA,Inc.,Geotechnical Investigation Report,Forward Landfill Expansion,February 2008. 15 The 2013 FEIR estimated closure dates with and without that project of 2039 and 2021,respectively.It should be noted that landfill closure dates are approximate and can vary greatly based on many factors such as the economy and density of wastes being disposed.