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identified in this document, these earlier settlement analyses are considered applicable for the current project. In support of the planned expanded Austin Road Landfill, the Report of Disposal Site Information (RDSI) and PCPCMP, R. W. Beck (1995) included an evaluation of the settlement potential of refuse and subgrade materials. As part of this work, R. W. Beck also evaluated the associated potential distress to the landfill liner system. Since the refuse loads that were anticipated by R. W. Beck are similar to those expected for the future Forward Landfill, the analyses that were completed by R. W. Beck are considered applicable for the current project. The results of this analyses are included in Appendix F. A geotechnical exploration was completed by CH2M Hill in 1992 to support stability and settlement analyses for development of the Forward Landfill. The geotechnical study included an exploratory drilling and laboratory testing program and calculation of the consolidation potential of subgrade materials and settlement of wastes. Considering the similarity of the final waste configurations for the currently proposed and historically proposed Forward Landfill, the CH2M Hill analyses appear applicable to the current project. Similarly, recognizing the consistency of the subsurface data collected in CH2M Hill's study and data that was collected during installation of monitoring wells at the Forward and Austin Road landfills, the CH2M Hill soil settlement analyses appear applicable to both sites. 5.3.4.2 SUBGRADE CONSOLIDATION As was the case when CH2M Hill completed its analyses in 1992, the current expansion plan for the Forward Landfill anticipates a maximum elevation of approximately 200 feet amsl. Calculation of the potential consolidation of native soils under this anticipated refuse load was completed by CH2M Hill based on the laboratory consolidation test data and standard penetrometer test blow counts collected in its geotechnical study (1992). As shown in Appendix F, these calculations indicate that the greatest refuse-induced soil consolidation will occur within currently undeveloped areas (up to 2 feet). Assuming no significant settlement at the toe of the landfill, the maximum differential consolidation of subgrade soils was calculated to be two feet in 550 feet, or about 0.36 percent. This magnitude of differential settlement can be easily accommodated by the various components of the liner system under the refuse fill. forward Landfill)TD 5-18 L\Allied\2000.193\Reports\JTD-PC PC MP7 02:Sec-5.0:5,/24;02 Revision 1:07/176/02 BRYAN A.STIRRAT&ASSOCIATES