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1] the south with a gradient of approximately 0.002 foot per foot. Groundwater flow velocity has been calculate to be 67 feet per year. Environmental Monitoring The current groundwater monitoring system is comprised of four monitoring wells, one upgradient well (MW -1) and three down gradient wells (MW -2, MW -3 and MW -3). Volatile organic compounds (VOCs) were first detected in 1991 in one groundwater monitoring well, MW -2. The cause of the impact was believed to be landfill gas migration. A landfill gas (LFG) collection system was installed in 1996 to mitigate groundwater impacts and control LFG migration. Three VOCs were reported consistently since first confirmed in 1991; however, recent monitoring data indicates one VOC remaining at very low concentration (tetrachloroethene below 1 ppb). An increasing chloride trend has been developing in MW -2, MW -3 and MW -4. Concentrations do not exceed the recommended secondary maximum contaminant level (MCL) for drinking water (25.0 mg/1) in wells MW -2 and MW -3 Run-off/Run-on facilities Harney Lane Sanitary Landfill utilizes several methods to control run-on and run-off. A_ perimeter berm/road surrounds the site and prevents water from entering. The facility utilizes drainage ditches along the berm/road to handle storm water runoff from the landfill. The ditches discharge to a stormwater retention pond located at the south end of the site. HYPOTHETICAL RELEASE SCENARIO Based on the current impact to groundwater by LFG, and that this is an unlined site, the most reasonably foreseeable release that will require corrective action is an elevation in VOCs rather than an elevation of inorganics as follows: An Evaluation Monitoring Program (EMP) will be conducted to investigate the lateral and vertical extent of a release from Harney Lane Sanitary Landfill. This EMP will consist of preparing a work plan for approval by the jurisdictional agencies, implementing the field investigation of this Plan, and reporting the findings. An EMP work plan will be submitted to the RWQCB in accordance with Section 20425 (a) and (b) of Title 27. The EMP will include a soil gas and groundwater step-out/step- Corrective Action Financial Assurance Cost Estimate 2 September 30, 2008 Harney Lane Sanitary Landfill San Joaquin County Public Works Department