Laserfiche WebLink
PROPOSED INVESTIGATION <br /> The County proposes to investigate two possible sources of groundwater impact: <br /> • Percolation of rainwater through refuse not covered by closure cap on the east side of the <br /> landfill. <br /> • Percolation of surface water contaminated by cattle feces through the creek bed. <br /> Potential percolation of rainwater through refuse beneath the drainage ditch will be investigated by <br /> assessing the extent to which refuse may extend under the ditch beyond the landfill closure cap at <br /> the eastern edge of the landfill. If refuse underlies the drainage ditch and/or the road in this area, <br /> then water flowing in the ditch could percolate through the refuse, thus contributing to the <br /> constituents found in monitoring wells MW-4 and MW-5. <br /> The County proposes to determine limits of refuse along the eastern side of the landfill by <br /> excavating a minimum of four exploratory trenches across the drainage ditch and road to the <br /> perimeter fence line. The depth of the explorations will be ten feet minimum,but will be deeper, <br /> if needed, to determine the elevation of the base of refuse. <br /> Information may be available fromtheShell Pipeline Company,who installed the petroleum <br /> pipeline at the eastern edge of the landfill in 1982. 'The County has contacted Shell Pipeline <br /> Company,asking if logs of materials encountered during installation of the were available for our <br /> review. We are directed by Shell to submit ihis requesf in writing, which was sent on February 8, <br /> 2004. <br /> Potential impact by grazing cattle will be investigated by sampling standing water in the creek <br /> after early fall/winter rains, analyzing it for fecal coliform and nitrate concentration. <br /> MITIGATION MEASURES <br /> Mitigation measures will be evaluated based on the results of this investigation; however, if refuse <br /> is found below the drainage ditch, a likely mitigation measure will be the installation of an <br /> impervious membrane liner to carry the water over the refuse-containing area,to the retention <br /> pond. <br /> WlCorrall Hollow\Groundwater Monitoring\CorrectiveActEval-Pian-Feb05.doc <br /> Plan to Evaluate Impacts to Groundwater $ San Joaquin County Public Works/Solid Waste <br /> Corral Hollow Sanitary Landfill February 10,2004 <br />