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The corrective action envisioned is based on the following assumptions: 1. The focus of the corrective action is source control. 2. The low level release of VOCs to groundwater will not require active groundwater cleanup (pump and treat, air sparging, etc.). This approach is justifiable given the remoteness of the landfill and absence of surrounding residences. 3. The primary objective of the corrective action is to stop increases in VOC concentrations in groundwater. The secondary objective is to remove VOCs entirely. Corrective action taken to mitigate the hypothetical release will include the following activities: I . Install four deep (approximately 200 feet) landfill gas extraction wells that extend to the base of Module "I" and are screened to capture deeper gasses. The wells will be connected to the existing LFG extraction system via new 3 -inch laterals and a new 6 -inch secondary header. The wells will be operated in a manner to reduce the amount of landfill gas escaping from the bottom of the landfill. 2. Activate three soil gas trenches installed beneath lined modules. This gas will also be carried into the LFG treatment system. Cost Analysis The cost of the corrective action plan and the EMP includes engineering design, field investigations, construction and associated materials, permitting, and final reports. Permitting associated with the project will include RWQCB and SJC well drilling permits. Costs are "contractor based", i.e., based on construction by contractor, not by County staff. The cost for constructing the LFG components are based on a contractor bid received for similar work at the Corral Hollow Landfill in June 2008. Costs for other components were escalated from the original 2007 costs by applying the inflation factor supplied by the California Integrated Waste Management Board. The cost of construction is approximately $521,000. The annual cost over the 30 -year corrective action period, including construction, operation and maintenance is estimated to be $56,000 (Table 1). Corrective Action Financial Assurance Cost Estimate 4 September 30, 2008 Foothill Sanitary Landfill Public Works/Solid Waste Div.