COMPLIANCE INFO_JTD 9/3/2025 - Laserfiche WebLink

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Project No. AU25.1274 | PCPCMP Foothill Sanitary Landfill 2 September 2025 2.0 CLOSURE 2.1 Limits of Waste and Final Cover Topography The final closure configuration for the FSL allows final elevations to the presently-permitted limit of 432 ft. mean sea level (MSL). Refuse will be placed within 200 feet of the property boundary, except in the southeastern portion of the project, where the County tentatively plans to retain the existing pond (Figure 5). At completion, the limits of waste will include approximately 674 acres (which excludes the pond area), entirely within the 800-acre parcel (Figure 2). The sequence of fill, and the extent of each module, will be selected by the County. However, the County reserves the option to place refuse on 750 acres, including the pond area, subject to fulfilling all CEQA and related regulatory requirements. The final grading contours are shown on Figure 6. 2.2 Closure Phasing Section 21090(b)(1)(D) of Title 27, California Code of Regulations (Prompt Incremental Closure), states, in-part, that "To the extent feasible, based on site-specific factors, the complete closure including final grading and installation of the final cover, for each portion of the landfill shall b e implemented as soon as possible after that portion reaches final elevation". The County will comply with this requirement as portions of the landfill reach final elevations. The upper portion of Module "I" has reached final elevation, and has received an ET final cover in 2006 (Figure 2). This area was accepted as "closed" by the Regional Water Quality Control Board. The County intends to close the remainder of the landfill also using an ET cover, similar to that now in place on the Top Deck area of Module "I". Based on performance modeling, the ET cover will be approximately 4.5 feet thick and constructed with appropriate on-site soils. Future closure phases will be considered when a portion of the landfill is available for closure that includes a reasonable portion of the permanent closed surface to the perimeter of the landfill. 2.3 Site Life and Volumetric Calculations The capacity of the FSL is anticipated to be fully consumed around 2087 (JTD Table 5). This estimate does not include the effect of settlement and consolidation, which is highly variable, and is dependent upon such factors as type of waste, waste thickness and moisture content, climate, and fill operations. The net capacity of the landfill (volume available to place refuse and cover soil, excluding LCRS and final cover) is estimated to be approximately 111 million cubic yards (CY) (JTD Table 5).