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for the Foothill Sanitary Landfill as part of the design of Module 1 (Report of Waste Discharge Related to the Permitting and Installation of Module 1 and Future Modules, Foothill Sanitary Landfill, San Joaquin County, California, November 2002, Appendix F, Attachment 2). Based on this evaluation, the design MPE for the landfill is a moment magnitude 8.0 event on the San Andreas Fault, located approximately 135 kilometers from the site. This seismic event is estimated to result in median horizontal peak ground acceleration (PGA) of 0.054g for "rock" subgrade conditions, which is a relatively low acceleration. The stability of the landfill was investigated in 2002 by Shaw Environmental, Inc. (Shaw), concurrent with the design of Module 1. This evaluation found that global slopes of 3.4 to 1 were stable (JTD Appendix F) as reflected in the proposed final grading plan. The calculated yield acceleration is 0.09g for the critical slope. The yield acceleration is almost twice the design PGA of 0.054g, indicating that seismic displacement is not likely. The FSL final cover- is sufficiently stable given the relatively flat final grades, low seismic acceleration, and the use of soil only in the final cover. A detailed stability analysis is, therefore, not necessary. However, stability analyses should be evaluated as part of the design of each cell of the landfill, because interim conditions may be more critical than the final landfill condition. Construction of the final cover and associated drainage structures will be certified by a third 10 party. During construction, the final cap will undergo continuous testing and inspection. This testing and inspection will conform to procedures set forth in an approved Construction Quality Assurance (CQA) plan which will be developed and included in the final closure plan. The CQA plan will conform to the requirements of Title 27 Sections 20323 and 20324. Drainage and Erosion Control Closure drainage controls include the use of grass -lined drainage swales and slope benches to downchutes that direct runoff to the toe of the landfill. From there, the water will flow into a series of large perimeter drainage ditches (12 feet wide) that will discharge to one of six storm water detention basins (Subappendix A Figure 1). Being detention basins, water will be allowed to fill the basins and then discharged to offsite natural drainage courses. The purpose of the detention basins is to attenuate peak flows off site and to control sediment via the particle settlement that can occur in the basins (Subappendix A). Erosion control of the final cover will be achieved through maintenance of vegetation on the surface of the landfill cap and ongoing repair of erosion damage, if any. An analysis of estimated soil loss due to erosion using the Revised Universal Soil Loss Equation (RUSLE2 software issued by the Natural Resources Conservation Service) was recently completed. The modeling 00 assumed that the FSL, when closed, is covered with ET cover soils. This assessment indicated Foothill Sanitary Landfill b -b Public Works/Solid Waste Preliminary CPCM Plan County of San Joaquin — Rev July 2010