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Non-Water Release Corrective Action Plan Corral Hollow Sanitary Landfill granular soils are susceptible to liquefaction and dynamic settlement, while the structure of silty clays and clays is not adversely affected by vibratory motion. Boring log data from EMCON (1988) and Kleinfelder (2007) were reviewed to evaluate subsurface conditions at the site. The majority of the foundation soils of the landfill are composed of dense, silty sand to sandy gravel and very stiff to stiff, silts and clays. The SPT blowcounts as reported on the boring logs were generally greater than 30 blows per foot at a depth greater than 25 feet. The depth to the water table varies across the site from 25 feet on the eastern portion of the site to greater than 50 feet on the western portion of the site. In accordance with the State of California (SCEC, 1999), if the groundwater table is not within 50 feet of the existing ground surface or of if the blow count of the soil materials is greater than a SPT blow count of 30 blows per foot, then an analysis for liquefaction effects is not necessary. In addition, based on the work by Ishihara (1985), no significant liquefaction is possible at the existing ground surface for a PGA of 0.52g if there is greater than 25 feet of non-liquefiable soil below existing grade (as exists at the site). Accordingly, based on a preliminary site screening for liquefaction, the potential for liquefaction (and associated dynamic settlement) at the site is • low. The groundwater is not less than 300 ft at this site. Based on site-specific seismic design parameters and foundation materials strength characteristics, impacts resulting from liquefaction and associated dynamic settlement are considered negligible, and outside of the definition of a reasonably foreseeable impact. 4.1.5 Impacts from Potential Slope Failure 4.1.5.1 Slope Stability Analysis Procedure To satisfy the requirements of CalRecycle's BMPs, the existing landfill prism and cover slopes were evaluated for dynamic stability by using the (horizontal) PGA from the MCE event at the site of 0.56g. The 1997 topographic survey prepared by the County and site descriptions from the Third Quarter and Annual Groundwater and Surface Water Monitoring Report prepared by the County of San Joaquin, 2013 were used as the basis to evaluate the dynamic stability of the existing landfill slopes. An evaluation of the static stability of the site slopes was not performed since dynamic stability is necessary for this analysis, and dynamic stability is a more rigorous itest of slope stability. Geo-Logic ASSOCIATES