ARCHIVED REPORTS XR0000290 - Laserfiche WebLink

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a 3.2 SITE FEATURES ' The current layout of the site as presently configured is presented on Figures 2 and 3 North Beckman Road is located on the west side of the site. Neighboring properties include a Shell gas station to the north, a Caltrans yard to the south, and a trucking company to the east The northern portion of the site is occupied by abandoned pits which were used to raise fish for mosquito abatement purposes. The pits are approximately 3 feet deep and are dry The southern portion of the site contains a wash rack and soil/water separator, two pump islands, a building containing office space and a garage, and covered parking. A 10-inch deep excavation is located between the pump islands. Underground features include a 7,000-gallon mosquito larvicide oil UST, a 1,000-gallon gasoline UST, a 6,300-gallon mosquito larvicide oil UST, electrical lanes, water lines, and a storm drain. ' Three monitor wells (MW-1, MW-4, and MW-5) are currently present at the facility f4.0 GEOLOGY AND HYDROGEOLOGY The site is located within the Central Valley Geomorphic Province of California The topography of the area is generally flat Soil boring and monitor well lithologic logs from the site indicate the area is underlain with silty sand to a depth of approximately 30 feet bgs, and silt with sand and clay below the 30 foot depth Sand and silty sand is present at a depth of approximately 50 feet bgs. The site geology is illustrated on the cross sections presented on Figures 4 and 5. The location of the cross-sections is shown on Figure 7 ' Groundwater flow, as identified in previous site investigation reports is to the northeast. The latest groundwater flow direction and contours for which data is available is presented on Figure 6 Table 1 presents a summary of groundwater depths and elevations. The depth to groundwater in 1987 was 38 feet bgs. By 1991 the groundwater level had dropped to approximately 54 feet bgs The water level rose slightly in 1996 5.0 CONTAMINATION AND REMEDIATION Soil analytical results are present on Table 2. Soil boring and monitor well locations are shown on Figure 7 The lateral extent of soil contamination is presented on Figure 8 and the horizontal extent of soil contamination is presented on Figures 4 and 5 ' LIPROJPCTMSAWOQICLOSURESMVC_LOD CLO 3 2 May 1997