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04 February 2004 AGE-NC Project No. 04-1128 Page 2 of 7 Geology, 1977).Rocks composing the basement complex of the Province have not been completely defined but are believed to be metamorphic and igneous in origin. The Modesto, Riverbank and Turlock Lake Formations and overlying Recent alluvium are the principal sources of domestic ground water in the 13,500-square mile San Joaquin Valley Ground Water Basin(Basin 5-22). The estimated depth to ground water at the site is approximately 30 feet below surface grade (bsg) based on information from Lines of Equal Depth of Water Wells Fall 1999,published by the San Joaquin County Flood Control District and Water Conservation District- FCD&WCD. Based on the map titled Lines of Equal Elevation of Groundwater Spring 1999 also published by the San Joaquin County FCD&WCD, the site is in an area where ground water flow direction appears to be south-southeast. The closest surface water is Mormon Slough, located approximately 200 feet north of the property. Mormon Slough is intermittently dry, as most water is diverted to the north via the Stockton Diverting Channel 2.2. UNDERGROUND STORAGE TANK REMOVAL On 11 February 2003, one 12,000-gallon diesel UST,piping and dispenser was removed from the site. The UST was removed by Tank Specialists of California under permit from the SJCEHD. A total of twelve soil samples were collected from the site. Three soil samples were collected from the floor of the excavation (T1-W, TI-C and T1-E); one soil sample was collected beneath the dispenser island(D-1); and eight soil samples were collected from the excavated soil(SP-1 through SP-8). The samples were analyzed at a laboratory for total petroleum hydrocarbons quantified as diesel(TPH-d)according to EPA Method 8015 Modified and volatile aromatics(benzene,toluene, ethyl benzene and xylenes:BTEX and methyl tertiary butyl ether:MTBE)using EPA Method 8021. TPH-d and total xylene was reported in sample D-1 (dispenser island) at 6,100 milligrams per kilogram (mg/kg) and 0.008 mg/kg, respectively. No TPH-g, BTEX or MTBE were detected in samples collected beneath the UST or in the composited stockpile soil samples. Copies of the analytical results are included in Appendix A. It is our understanding that no additional authorized investigation has been performed at the site since the removal of the UST and sampling of the excavation. 3.0. SCOPE OF WORK AGE proposes to collect soil samples to determine if petroleum hydrocarbon-impacted soil and/or ground water is present beneath the site. The preliminary site assessment will include the following tasks: Advanced GeoEnviron mental,Inc.