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FORWARD LANDFILL NON-WATER CORRECTIVE ACTION PLAN lower strength material was used to model the interface to be conservative. The results of the analysis are presented in Table 2 and indicate a static factor of safety greater than 1.5. Table 2 also presents the yield acceleration(ky) of the cover system. Since the yield acceleration(0.48g) is about 3 times greater than the calculated site acceleration from the MCE event(0.15g), no significant permanent dynamic displacement is anticipated for the existing final cover system. In summary, the potential for impacts resulting from the design MCE site acceleration is considered negligible, and outside of the definition of a reasonably foreseeable impact. 4.2 PRECIPITATION IMPACTS CalRecycle staff recognizes that 1,000-year, 24-hour storm events have occurred in California and solid waste landfills that are Class II landfills are now required to be designed to withstand the 1,000-year, 24-hour storm event. The CalRecycle Proposed BMP for precipitation, as a causal event, is the 1,000-year, 24-hour storm event. The Forward Landfill is a Class II disposal facility for which the permanent storm water run-off and drainage systems have been designed to accommodate the 1,000-year, 24-hour storm event. ® The 1,000-year storm event flows have been analyzed and are included in the approved Closure plan which was included in the Joint Technical Document(JTD) for the Forward Landfill. The precipitation data for a 1,000-year, 24-hour storm event currently on the National Oceanic Atmospheric Administration(NOAA) website (see attachment in Appendix A), for the 1,000- year storm the rainfall intensity is 4.92 inches during a 24-hour period. All V-ditches and channels were sized for a minimum 1,000-year storm event based on a rainfall intensity 4.53 inches of precipitation. The difference between the 4.53 inches of precipitation and 4.92 inches of precipitation is only 0.39 inches(8%). Since the drainage conveyance system has been designed to have a minimum capacity to convey the design storm, the maximum capacity is greater. The V-ditches and channels designed on site have a range of additional conveyance capacity from the design storm used in the closure plan from 33 to 53% see Appendix A. Therefore the site design drainage conveyance system has adequate capacity to handle the small increase in rainfall intensity from the design storm used in the closure plan to the current value published on the NOAA web site. Therefore, the potential for impacts from the 1,000-year, 24- hour storm event are considered to have been addressed. M:\2011-0128�1VNWFA REPORT.DOCX 15 Geo-Logic Associates