SITE INFORMATION AND CORRESPONDENCE

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' 2.OSITE GEOLOGY AND HYDROGEOLOGY The Site is located in the City of Stockton, San Joaquin County, California. Stockton is located within the Great Valley geomorphic province of California. Soils are derived from river and floodplain deposits associated with the Calaveras and San Joaquin Rivers, and are comprised of ' sand, silt and clay. Depth to groundwater in the vicinity of the site is approximately. 50 feet below ground surface. ' The terrain in the area is flat. Regional groundwater flow is to the west from the site, towards the San Joaquin River, which is one of the two principal drainage conduits for the Great Valley. However, during the summer. months high agricultural usage of groundwater occurs and ' hydraulic gradients are known to change direction in response to high yield pumping from irrigation wells. ' In the shallow soil borings drilled at the site, a stiff, black clay occurred as the first encountered native material to depths of four to six feet.below ground surface. This clay ' (known locally as Adobe clay) contains minor plant remains and clasts of weathering feldspars. Below the black clay, a dark reddish brown clay exists to an unknown depth. The encountered soil types are typical of low permeability soils which would act to retard the ' vertical movement of liquids into the subsurface. 3.OSITE LAYOUT The Lee Galles Oldsmobile dealership is located within a complex known as the Stockton Auto ' Center and situated in the southeast portion of the complex. The lot is covered by two main buildings, one building accommodates the dealership showroom and the sales and administrative offices, the other building is occupied by the service department, including the car wash. The onsite buildings occupy a combined area of 26,325 square feet in the central portion of the lot. The rest of the site consists of asphalt parking areas and landscaped garden islands. Figure 5 ' is a detailed scale site map. 4.0ENVIRONMENTAL COMPLIANCE A review of the records from the San Joaquin County Department of Health Services, City of Stockton Public Works, and the City of Stockton Fire Department was requested. Copies of the ' interview reports and files reviewed are available in Appendix B and D. A brief summary follows: County Department of Health Services - A Freedom of Information request was made to Margaret L.agorgio, lead senior registered environmental health specialist for San Joaquin ' Privileged and Confidential Prepared at the Request of Counsel 16