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Non-Water Release Corrective Action Plan Corral Hollow Sanitary Landfill • infinite slope method of analysis using the soil parameters presented previously. The analysis assumed a potential failure plane through the low permeability layer as well as the underlying foundation layer. The yield acceleration (ky) was calculated for the 5:1 (horizontal to vertical) slope cover configuration for both cases; • Case 1: Failure in the low permeability cover layer (Figure B-4, Appendix B), and • Case 2: Failure in the underlying sandy cover foundation layer (Figure B-5, Appendix B). The results of the analyses are presented in Table 5: TABLE S COVER SYSTEM SLOPE STABILITY RESULTS POTENTIAL FAILURE LAYER OF COVER FIGURE NO. Ky Case 1: Failure in the low permeability cover layer B-4 1.36g Case 2: Failure in the underlying sandy cover foundation layer B-5 0.37g Based on the yield acceleration values provided above, permanent seismic displacement calculations were performed for the cover systems in accordance with the procedures described above (Table B-2, Appendix B). The results of the calculations indicate seismic . displacements ranging from 0 (for Case 1) to 2 inches (Case 2) of permanent dynamic displacement under the loading of the PGA from the MCE design earthquake. In accordance with CalRecycle's BMPs, 2010, Table 2, page 5, this magnitude of displacement is considered de minimus for ground motion and the cost for corrective action is not required. For the 1.6 acres at the northeast portion of the landfill, a slope stability analysis was performed by Shaw (2012) for a PGA of 0.56g (equal to the MCE calculated herein). Based on the results of the Shaw report, a maximum seismic displacement of approximately 10 inches is calculated. A permanent displacement of 6 to 12 inches is considered as the maximum allowable limit based on the RCRA Subtitle D (258) Seismic Design Guidance for Municipal Solid Waste Facilities (US Environmental Protection Agency, 1995). Additionally, the design guidance document goes even further in specific references to cover systems, and suggests that "...larger permanent deformations may is considered acceptable," due to the ease of accessibility for repair post-earthquake. Based on our calculations, significant impacts resulting from dynamic displacement of the final cover under loading of the MCE event are considered outside of the definition of a reasonably • foreseeable impact. 11 Geo-Logic ASSOCIATES