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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 Stdckton 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 Topography in the area is generally flat, although the project site is elevated several feet above the adjacent parcels There is a maintenance building and office fronting Newton Road, with a large, unpaved storage yard/parking 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 When soil samples were collected after the UST facility was removed, diesel and some gasoline contamination was discovered Assessment of its extent began shortly thereafter, when two borings, including a monitoring well, were drilled in September 1994, Upgradient Environmental Consultants was retained by Gillies Trucking to continue the assessment 2.0 PROCEDURES Groundwater monitoring took place on March 7 The wells were opened and allowed to equalize with atmospheric pressure before water depths were measured The depth to groundwater in each well was measured with a Solinst water level meter and the measurements were recorded on the Well Morntor Report (Appendix A) It was still not possible to locate well GT-2, which has been buried under road aggregate since December 1999 The wells were not purged before samples were collected This was done as a further test to determine whether purging affects the sample results (see section 4 0) The samples were collected in disposable plastic bailers and transferred to l-liter amber bottles and 40-m1 vials and then shipped to McCampbell Analytical in a chilled ice chest All samples were analyzed for TPH- diesel, and the sample from GT-10 was also analyzed for TPH-gasoline and BTEX 3.0 RESULTS 3.1 Groundwater Gradient and Flow Direction Depth-to-groundwater measurements and calculated groundwater elevations are presented in Table 1 Results from previous monitoring events are included for comparison The static water level has risen more than a foot since December 2000, and now ranges from 51 to 54 feet below grade In the past few years, the depth to water at this time of year has generally been in the 45 to 48-foot range 2