Laserfiche WebLink
2.0 Evaluation Monitoring Program Work Plan <br /> The County proposes an evaluation monitoring program that includes the installation of one <br /> permanent groundwater monitoring well and groundwater sampling at three temporary borings. <br /> Permanent groundwater monitoring well MW-8 is proposed along the perimeter road of the <br /> landfill adjacent to vadose zone soil gas well GW-2 (Figure 2). The purpose of this well is to <br /> assess the extent of groundwater impact along that portion of the landfill perimeter. A well in <br /> this location will also better define the direction of groundwater flow in the shallow aquifer. <br /> Three temporary soil borings (Figure 3 —tentative locations)will be drilled for the purpose of <br /> collecting vadose zone soil gas samples at three depths each and for the collection of <br /> groundwater using HydroPunch or equivalent technology. Their locations are: <br /> 1. East of Interstate 580 within the open field <br /> 2. Across Interstate 580 northeast of the site <br /> 3. In the field north of the CHLS and across Corral Hollow Road. <br /> The City of Tracy trash burn dump was located on one or more of the parcels of Area No. 1 (east <br /> if Interstate 580). Experience at Shaw indicates that the presence of burned refuse above an <br /> aquifer does not necessarily impact the aquifer below. However, boring through the burned <br /> material could allow burned material to enter the aquifer by falling down the bore,potentially <br /> carrying contaminated material into the aquifer. The location of the temporary sampling location <br /> in this area will attempt to avoid boring through the burned refuse residue. <br /> The purpose of the soil gas samples is to determine the later and vertical extent of VOC impact <br /> within the vadose zone to the north and east of the landfill. The purpose of the hydropunch <br /> samples is to determine the lateral extent of groundwater impact downgradient from well MW-5 <br /> in the shallow aquifer, if any. <br /> Drilling on offsite properties is subject to permission granted by the landowners. The County <br /> has contacted the owners of these properties, requesting permission to perform the work of this <br /> Plan. As of February 24, 2007, permission to enter has not been granted; however, County staff <br /> reports that the discussions have been cordial, and that permission to enter the property is <br /> expected. <br /> Corral Hollow EMP WP.DOC 2_1 February 28,2007 <br />