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1.0 INTRODUCTION • The project site is located at 3931 Newton Road in an industrial area on the northeast outskirts of .l st Stockton near U S Highway 99 The location of the site is shown in Figure 1, and the site facilities are shown in Figure 2 Originally agricultural property, the site was developed as a commercial truck terminal in 1973 The property occupies an area of about 3 5 acres Topogiaphy in the area is generally flat, although the project site is elevated a few feet above the adjacent parcels There is a maintenance building and office fronting Newton Road, with a large, unpaved storage yard/paiking lot in the rear A diesel and gasoline fueling facility, consisting of two underground storage tanks (UST's), was formerly present on the south side of the storage yard (Figure 2) This facility was removed in 1989 and replaced with an aboveground fueling facility, which is located to the west of the abandoned facility 2.0 PROCEDURES Groundwater monitoring took place on September 3 The wells were opened and allowed to equalize with atmospheric pressure, and then the depth to groundwater was measured with a water level meter The measurements were recorded on the Well Monitor Report (Appendix A) before the wells were purged Samples were collected in disposable plastic bailers and transferred to 1-liter amber bottles A sample was also collected at the tap on the domestic well (G-1), but electricity to the pump on the Barbot well has been shut off and that well could not be sampled The samples were labeled and placed into a cooled ice chest for later shipment to the laboratory All samples were analyzed for TPH-diesel The laboratory report is contained in Appendix B 3.0 RESULTS 3 1 Depth to Groundwater Table 1 provides all depth-to-groundwater measurements and calculated groundwater elevations The depth has increased by about 5 feet since May, and now ranges from 64 14 to 65 86 feet This places the static water level just below the base of the silt and clay beds of the lower Modesto Forination, in the sand at the top of the Riverbank Formation 3 2 Hydraulic Gradient and Groundwater Flow Direction The calculated water table elevations were used to construct the groundwater elevation map in Figure -3) Elevation contours again form an are that is centered on GT-1, where the static water level is at an elevation of 38 86 feet below sea level The water level is higher to the east, north, and west of GTA, implying that the groundwater flow direction is radial toward the low spot in the vicinity of GT-1 The hydraulic gradient between GT-5 and GT-1 is roughly 0 006 ft/ft, which is a neatly the same as the 0 005 ft/ft calculated in May and slightly steeper than the 0 003 ft/ft in March �� 2