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1 3 The Eastern San Joaquin Subbasin is drained by the San Joaquin River and several of its major tributaries namely,the Stanislaus,Calaveras,and Mokelumne Rivers. The San Joaquin River flows northward into the San Francisco Bay. The average rainfall in the Eastern San Joaquin Subbasin ranges from 11-inches in the southwest to about 25-inches in the northeast(DWR, 2003). Water bearing units in the basin in descending order consist of the Recent to late Pleistocene age Alluvium and Modesto/Riverbank Formations,the Plio-Pleistocene age Laguna Formation,and the late Miocene to Pliocene age Mehrten Formation (DWR, 2003). 2.4 Depth to Groundwater The depth to groundwater in the Site vicinity varies between 55 feet below the ground surface(bgs) and 65 feet bgs according to the San Joaquin County Department of Environmental Health(Lagorio, 2003a). 3.0 SOIL SAMPLING BENEATH FUEL DISPENSERS, PRODUCT PIPING AND AN OIL DISPENSER ' 3.1 Soil Sample Collection On September 18, 2003, soil samples were collected by FREY personnel, under the direction of a State of California Certified Engineering Geologist, at the locations shown on Figure 2. One soil sample was collected from beneath each of the nine diesel dispensers from depths between 4.5 feet bgs and 5.5 feet bgs. Five soil samples were collected from various locations beneath the product piping as shown on Figure 2 from depths between 4.5 feet and 5 feet bgs. Finally, one soil sample was collected from beneath an oil dispenser from a depth of approximately 5 feet bgs. Soil sample locations and depths were specified by Dina Abate of the San Joaquin Department of Environmental Health on September 18, 2003. A backhoe was used to excavate through pea gravel to an approximate depth of 3 feet bgs at each sample location. FREY then hand angered to the depth requested by Ms.Abate. Soil samples were collected by emptying the cuttings from the hand auger barrel and hand packing a brass tube with the cuttings. Each sample was labeled with the project number,sample number,depth,time and date of sample collection. After sample collection,the brass tubes were capped with teflon tape ' and an air tight plastic cap, placed in plastic bags, and stored in an ice chest cooled with ice. The soil samples and the associated chain of custody were transported to the laboratory at the conclusion of soil sampling activities. Soils sampled consisted of a dark brown to black, damp, silty clay from below the pea gravel to the bottom of the deepest soil sample location at approximately 5.5 feet bgs. Groundwater was not ' encountered during this investigation. ' FREY