COMPLIANCE INFO_JTD 9/3/2025 - Laserfiche WebLink

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Foothill Sanitary Landfill 4 Department of Public Works/Solid Waste First Semiannual 2025 Groundwater Monitoring ©2025 County of San Joaquin. All rights reserved. On October 30, 2003, the County submitted a final EFS report to the CVRWQCB presenting the results of the Evaluation Monitoring Program, which indicated that the groundwater was no longer impacted. Corrective action was identified as completed in 1998 - preventing further ponding on the landfill surface near MW-3. Closure of Module “I” was discussed but was not proposed as further corrective action due to the apparent success of previous corrective action, indicated by the of lack of groundwater contamination. On December 16, 2003, an Administrative Civil Liability Complaint was issued by the CVRWQCB for not submitting a Closure Plan for Module ’I”. At that time, groundwater contamination had not been detected at MW-3 for nearly two years and no other groundwater monitoring well indicated contamination. Negotiations in January 2004 resulted in a Cleanup and Abatement Order (R5-2004-0706) which required the County to initiate the Foothill Landfill Site Improvement Project, which included:  Final closure of the top deck area of Module “I”  Installation of a barrier between Module “I” refuse and the future refuse placed over Module “I” in extension and completion of Module 1  LFG collection  Placing Partial Cover of those surfaces of Module “I” that are not covered by the inter- area barrier or final closure  Installation of two groundwater monitoring wells The Cleanup and Abatement Order required the County to install a gas-tight barrier (equivalent to a base landfill liner such as that required to place refuse on native soil) over refuse in Module “I”. This barrier was installed in spite of County objections, based on concern that covering unlined refuse with an impermeable top barrier would result in gas migration downward from the unlined base, impacting groundwater. This project was pursued in lieu of complete closure of Module “I”. On July 20, 2004, the San Joaquin County Board of Supervisors approved a contract with Kleinfelder to design the Site Improvement Project. In mid-2006, the gas-impermeable HDPE liner material was placed over LF-1 (Module “I”) refuse. By February 2007, five years after the groundwater was found to be impact-free, construction of the Site Improvement Project was substantially complete; however, the vegetation in the evapotranspirative (ET) cover was not well established. Further work was needed to establish the vegetation. In November 2007, the ET area was again reseeded, but growth remained insufficient for adequate ET cover. In November 2008, the closure cap soil was amended and fertilized, and again seeded.