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17 January 2000 AGE-NC Project No. 99-0641 Page 2 of 6 TPH-g and TPH-mo were not detected above laboratory reporting limits in the soil samples collected beneath the former UST area. TPH-d was detected in soil sample T3N collected beneath the former UST area at concentration of 100 mg/kg. BTEX compounds were detected in soil samples collected beneath the former USTs at concentrations as high as 440 pg/kg. TPH-g and TPH-mo were detected in soil samples collected from the stockpiled soil at concentrations as high as 6.3 mg/kg and 48 mg/kg,respectively. Lead was detected in one composite soil sample collected from the stockpiled soil at a concentration of 38 mg/kg. A summary of soil analytical results are presented in Table 1. 2.3. REGIONAL GEOLOGIC/HYDROGEOLOGIC SETTING The property is situated within the Great Valley Geomorphic Province of California, a large, elongate, northwest trending, asymmetric structural trough. The Great Valley Province has been filled with thick sequences of sediment ranging in age from Jurassic to Recent, 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 the California Coast Range and the Sierra Nevada, respectively. Rocks composing the basement complex of the province have not been completely defined but are believed to be of metamorphic and igneous origins. The northern and southern portions of the Great Valley Province have been designated the Sacramento and San Joaquin Valleys, respectively. The Modesto, Riverbank and Turlock Lake Formations and overlying recent alluvium are the principal source of domestic ground water in the 13,500-square-mile San Joaquin Valley Ground Water Basin (Basin 5-22). This basin is drained primarily by the San Joaquin River. The nearest surface water feature in the vicinity of the property is the Moklumne River approximately one-half mile north of the subject property. The estimated depth to ground water at the property is approximately 30 to 35 feet below surface grade (bsg), based on the map titled Lines of Equal Depth to Groundwater Spring 1996 published by the San Joaquin County Flood Control District and Water Conservation District (FCD&WCD). The map titled Lines of Equal Elevation of Groundwater Spring 1996, also published by the FCD&WCD, shows the property to be in an area where ground water flows toward the south and southwest, but this may be modified by changing recharge and discharge patterns. Ground water is considered to be of beneficial use and is used for domestic, industrial and commercial purposes. The inferred ground water flow direction at the near-by site is toward the southwest. Advanced Geo Environmental.Inc.