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Non-Water Release Corrective Action Plan North County Recycling Center and Sanitary Landfill ® The post-closure maintenance plan discusses and has funding to provide post-closure maintenance activities such as cover repairs, erosion rills in the cover, cover sags, drainage maintenance, etc. Therefore, the long-term performance of the final cover is adequate for the life of the closure and no further assessment needs to be considered in this NWRCAP, and long- term performance issues are not considered reasonably foreseeable causal event for this facility. 5.0 ANTICIPATED METHODS OF MITIGATION 5.1 Mitigation of Seismically-Induced Impacts Seismically-induced impacts are not a reasonably foreseeable casual event; therefore, no mitigation is required. 5.2 Mitigation of Precipitation Related impacts As discussed in Section 4.2, capacity at 7 downdrain locations is inadequate to convey run-off from the 1,000-year, 24-hour storm event and would cause the bench channels to back-up and overflow at the inlets, and is a reasonably foreseeable causal event for this facility. Although the benches have capacity to contain the additional run-off, the flows would likely cause localized erosion along the bench. It is assumed that the damage from runoff of the 1,000-year, 24-hour storm event would require reconstruction and reconditioning of the benches. For cost estimating purposes, it was assumed that rivulets along an area the width of the bench (12.5- feet not including the channel) and 50-feet in length would need repair to a depth of no more than 1-foot. The cost to excavate soil debris, reconstruct channel edges, replace vegetative cover soil, and place erosion control for these channels is estimated at$83,993 (see Table D-1, Appendix D). 5.3 Mitigation of Fire-Related Impacts 5.3.1 Subsurface Fires As discussed in Section 4.3.1, subsurface fires are considered a potential casual event due to the landfill gas extraction system. Like all fires, subsurface landfill fires can be extinguished by removing one of the tetrahedral components (oxidizing agent, fuel, heat). This can be excavation and soil burial, injection of Type A foam, or by turning off the landfill gas system. The suppression method, however, is unique to each situation. Since the landfill is still operational, it is assumed that a subsurface fire will begin around a single malfunctioning landfill gas extraction well and will be identified and controlled after 2013.A135 I N:\San Joaquin\North County\Non-Water Release CAP\Final Report\North County_NWCAP_Report_Final.docx July 2014,Rev.0 14