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17 June 2003 AGE-NC Project No. 03-1043 Page 2 of 6 being primarily continental. Continental-derived sediments were primarily deposited in lacustrine, fluvial,and alluvial environments with sediment sources being the mountain ranges surrounding the valley(Olmsted and Davis, 1961);the site itself is located on unconsolidated and semi-consolidated alluvium, lake, playa and terrace deposits of Quaternary age (California Division of Mines and 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 40 to 50 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 local ground water elevation is generally toward the east. However, this may be greatly modified by local recharge and discharge patterns. 2.2. POTENTIAL SOURCES OF CONTAMINATION The previous Phase I site assessments revealed several potential sources of contamination due to prior uses of the property: • Contamination to the subsurface from the hazardous materials storage area, • Contamination to the subsurface from surrounding properties, • Contamination from the pad mounted transformer and associated maintenance. 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 Phase II site assessment will include the following tasks: • Permitting and pre-field work activities; • The advancement of four probe borings to approximately 10 feet bsg and four probe borings to ground water; • Soil sample collection and analysis; • Report preparation