COMPLIANCE INFO_JTD 9/3/2025 - Laserfiche WebLink

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3-13 3.1.4 Liquefaction and Fault Rupture Potential In addition to assessing the costs that would result due to landfill damages from an MCE event, the NWRCAP also requires an assessment of the following:  Potential effects of liquefaction if the landfill is located in a Seismic Hazard Zone.  Potential damage from fault ruptures if the landfill is located within 200 feet of Holocene fault zones. The FSL is not located in a Seismic Hazard Zone, nor is it located within 200 feet of a Holocene fault zone, as shown on figures contained in Appendix A. Liquefaction and fault rupture potential are therefore not applicable to the FSL site. 3.2 Precipitation Causal Event According to landfill research there are case studies that document damage to landfills caused by storms. Damage to the final cover, displacement or exposure of waste, damage and clogging of the drainage system, and failure or erosion of slopes and roads can occur due to erosion of soil and inundation by water. Although every landfill is unique in its design and location, precipitation is a reasonably foreseeable causal event. Landfills are required to maintain stormwater management / drainage systems to safely manage and control run-on and run-off due to precipitation during their active life and through their post-closure period. Class III landfill stormwater management / drainage systems are required to protect against a 100- year, 24-hour storm event; and Class II landfill stormwater management / drainage systems are required to protect against a 1000-year, 24-hour storm event. The BMP for precipitation as a causal event is the 1,000-year, 24-hour storm event — specifically, an assessment of damages that could occur during the 1,000-year, 24-hour storm event and the required corrective action / repairs and associated costs. The FSL is a Class III landfill, and therefore the site stormwater management / drainage system has been designed to safely manage and convey rainfall from the 100-year, 24-hour storm event, or 4.03 inches of rainfall. The amount of rainfall on the FSL site due to the 1,000-year, 24-hour storm event is 5.42 inches, or 1.39 inches more rainfall than the 100-year, 24-hour storm event (5.42 inches - 4.03 inches = 1.39 inches). Supporting data from the National Oceanic and Atmospheric Administration for the 100-year and 1,000- year storm events are provided in Appendix B. Because the FSL stormwater management / drainage system is designed to the Class III standard of the 100-year, 24-hour storm event, it is reasonable to assume some damage may occur to the following landfill features from a 1,000-year, 24-hour storm event:  Final cover soil and vegetation, and  Stormwater management / drainage system sedimentation basins and perimeter drainage ditch.