COMPLIANCE INFO_JTD 9/3/2025 - Laserfiche WebLink

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WASTE DISCHARGE REQUIREMENTS ORDER R5-2015-0058-01 -33- SAN JOAQUIN COUNTY DEPARTMENT OF PUBLIC WORKS FOOTHILL SANITARY LANDFILL, INC. FOOTHILL LANDFILL SAN JOAQUIN COUNTY management unit.13 The plan scope consisted mostly of closing LF-2, given that at closure, LF-2 would completely encircle LF-1, Module I’s closed top deck, less the thickness of final cover soil to be applied. Proposed landfill closure activities would include grading and final cover installation; modifications and improvements to the landfill’s monitoring systems and LFG control facilities; and various site improvements associated with landfill closure (e.g., drainage controls, demolition/decommissioning, survey monuments, site security). 138. The plan anticipated installation of a 4.5 foot thick ET cover over LF-2 similar to that installed on LF-1’s top deck in 2006, utilizing existing intermediate cover soil. For preliminary planning purposes, the proposed ET cover would likely rely on the test pad demonstration conducted at LF-1 for its EAD demonstration. The closed landfill (i.e., LF-1 and LF-2) would be approximately square-shaped with a maximum final cover elevation of 432 feet MSL occurring along the spine of a boot-shaped top deck. Proposed final cover side slope grades (3.4H:1V) and setback from the site perimeter (200 feet) would generally be the same as the interim cover slopes of completed modules. The top deck would be graded to drain at a 6 % slope toward grass-lined cover drains along the flanks of the unit that discharge to overside drains. Grass- lined bench drains would collect sheet flow runoff from the landfill side slopes and direct it to the overside drains. The overside drains would discharge to a series of large (12 foot wide) drainage ditches connected to elongated storm water detention basins (100’ wide x 500’ long) along the perimeter of the unit to reduce peak flow discharges. The perimeter drainage system would discharge to the large storm water (i.e., stock) pond in the southeast corner of the site. 139. The 30 July 2010 PC/PCMP did not include final cover slope stability analysis because none of the proposed final cover slopes are steeper than 3H:1V and a geosynthetic component is not being proposed as a component of the cover. See Standard Closure and Postclosure Specification G.14, SPRR. Also, limited global slope stability analysis conducted for the design of LF-2’s containment system indicated that final cover slopes with an ET final cover would likely be stable in accordance with the requirements of Title 27. See Finding 97.c. 140. The 30 July 2010 PC/PCMP did not include a specific plan for partial/phased landfill closure; however, it indicated that the landfill would likely be closed in phases. Phased closure would proceed once a sufficient number of adjacent expansion modules had been developed to constitute a closable phase. The first closure phase would not likely begin before the year 2024, however. These WDRs require that the Discharger partially close LF-2, as feasible as the landfill is developed, per Title 27 requirements. See Closure and Postclosure Specification E.4. 13. See 30 July 2010 Preliminary Closure and Postclosure Maintenance Plan, Foothill Sanitary Landfill, San Joaquin County, prepared by Shaw Environmental, Inc. (Appendix B, JTD).