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�+ %.d encountered (noted at"Former Tank" on Figure 3). The UST was removed under the oversight of the SJCEHD, and confirmation samples were collected. Sidewall soil confirmation samples were collected at approximately every 25 linear feet and every 3 vertical feet ranging between 3 to 15 feet below ground surface(bgs). Soil confirmation samples collected from the bottom of the excavation ranged between 2.5 and 17 feet bgs. The excavation dimensions were chosen to remove the majority of the identified soil contamination (i.e. as noted in the RDIP) and contamination from the discovered previously unknown UST(T&R, 2005). Approximately 2,615 cubic yards (bench yards) of contaminated soil was excavated. Groundwater was not sampled during the excavation activities. At the bottom of the excavation, soil confirmation samples were collected at 15 and 17 feet. The 15-foot bgs sample had a TPHg, TPHmo, Ethyl-benzne, and o-Xylene concentrations of 2,800, 190, 7.5, and 21 milligrams per kilogram (mg/kg), respectively. The 17-foot bgs sample had a TPHd concentration of 390 mg/kg. All other TPH and VOC analytes were non-detect at these two locations (T&R, 2005). k. Since the completion of soil excavation and groundwater extraction, no further investigation or monitoring has occurred at the Site. During this period, the Site has been redeveloped as part of the Stockton Arena complex. 3.0 SOIL AND GROUNDWATER CONDITIONS �4r Groundwater has generally been encountered in wells at the Site at approximately 16 to 18 feet below ground surface (bgs). The Site was identified, based on previous investigations AGE, to be underlain by two potential hydrogeological units informally identified as the Upper and Lower Water Zones. Previous investigations have identified a low permeable layer of clay and silty clay at approximately 40 to 45 feet below ground surface(bgs), which separates the shallow aquifer into an A zone (to 40-feet bgs)and a B zone(deeper than 45 feet). There were previously three nested well locations that had both A and B zone wells (MW-19A&MW-196, MW-20A&MW-2013, and MW-21A&MW-21B). Groundwater elevations in the B zone were approximately 1.5 feet lower than the A zone, indicating that a downward gradient is present. Historical groundwater monitoring performed by AGE indicates that the groundwater flow direction to be consistently towards the North-Northeast in the Upper Water Zone. Groundwater flow direction in the .. Lower Water Zone had been toward the West-Northwest, Southwest and Southeast(AGE, 2002). �r 3 �r 25971030.DGD 9 October 2009 �r