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saturated zone, approximately 35 feet. Soil samples were collected . at each five feet commencing at 11 feet. A grab water sample was collected. Figure 2 presents the location of the former UST area and B-T. The soil and groundwater samples were analyzed for Total Petroleum Hydrocarbons as Gasoline (TPHG) and Benzene, Toluene, Ethylbenzene and Xylene (BTEX) using Modified EPA Methods 8015/8020. Based on the results of the analysis from the initial boring, San Joaquin County Environmental Health Division (SJCEHD) required an additional subsurface .investigation to better define the extent of the soil and possible groundwater contamination. JPCA addressed the county requirements and prepared a workplan which was accepted by SJCEHD. A permit was requested and received from SJCEHD prior to drilling the three borings and three monitoring wells. In October 1994 , the borings and wells were completed with soil and groundwater samples collected for analysis. Soil samples collected from a depth of 20 feet to groundwater at approximately 30 feet were analyzed and contained gasoline and gasoline constituents. Groundwater samples contained actionable levels of gasoline and gasoline constituents. FIELD WORK GRADIENT DETERMINATION Prior to purging and sampling, on September 11, 1996, the depth to groundwater was measured by an electronic probe in the three Monitoring Wells on site, see Figure 2 for locations of the wells on site. The water depth was measured from a mark located on the top of the casings. The groundwater gradient data are presented in Table 1 . The calculated gradient is S 47o W or 2270 at 0. 007 ft/ft. The groundwater gradient is depicted in Figure 2 . Field notes are contained in Appendix A. TABLE 1 Groundwater Elevations (ft) - Sept. 11, 1996 Well ID Top of Casing Depth to Water Groundwater Elevation MW-1 40. 00* 24 .96 15. 04 MW-2 40. 03 25 . 02 15. 01 MW-3 39 . 43 24 . 18 15. 25 * Assumed elevation 3