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13 August 1997 AGE-NC Project No. 97-0330 Page 2 of 6 Department of Mines and Geology, the site area is within the Great Valley Geomorphic Province of California, a large, elongate, northwest trending structural trough. The Great Valley Province has been filled to its present elevation with thick sequences of sediment ranging in age from Jurassic to present day, creating a nearly flat lying alluvial plain extending from the Tehachapi Mountains in the south to the Klamath Mountains in the north. The western and eastern boundaries of this province are comprised of the California Coast Range and the Sierra Nevada, respectively. The Great Valley Province is subdivided into two major divisions designated the Sacramento and San Joaquin Valleys. Furthermore, based on the General Soil Map from the San Joaquin County Soil Survey, published by the United States Department of Agriculture Soil Conservation Service in 1992, the site area is Within the Jacktone-Hollenbeck-Stockton(JHS) association. The JHS soils are located within basins, and generally consist of moderate to poorly drained fine textured soils. The soils are generally derived from both marine and non-marine sediment, and are generally formed in alluvium derived from mixed rock sources. 2.3. GROUND WATER DEPTH AND GRADIENT According to the map titled Lines Of Equal Depth Of Water Wells-Fall 1993, published by the San Joaquin County Flood Control and Water Conservation District, the estimated depth to ground water at the property is approximately 80 feet below surface grade (bsg). The prevailing ground water flow direction in eastern Stockton is generally toward the northeast, although flow directions may vary locally and seasonably. According to information obtained from the PHS-EHD, the long term rise of ground water near the site occurs at approximately 50 feet below surface grade (bsg). 3.0. SCOPE OF WORK Based upon the detection of total petroleum hydrocarbons quantified as diesel (TPH-d), the PHS- EHD is requiring further assessment at the site. In a letter dated 17 July 1997, the PHS-EHD is requiring assessment of TPH-d in both soil and ground water. 3.1. DRILLING ACTIVITIES AGE proposes to advance a minimum of two soil borings to depths of approximately 60-feet bsg. One soil boring will be advanced near the location of soil probe boring P-2 (Figure 2). The boring will be advanced directly into ground water, and a grab ground water sample collected. The second boring will be advanced approximately 40-feet northeast of P-2, and soil samples collected at 5-foot intervals Advanced GeoEn ironmental,Inc.