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27 December 2004 AGE-NC Project No. 04-1239 ' Page 2 of 8 ' 2.2. 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 comprised of 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 metamorphic and igneous in origin. The northern and southern portions of the Great Valley Province have been designated the Sacramento and San Joaquin Valleys,respectively. ' 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 Jackson-Hallenbeck-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. The Modesto,Riverbank,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 WaterBasin (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 Calaveras River, approximately 3,000 feet north of the tproperty. ' 2.4. GROUND WATER DEPTH AND FLOW DIRECTION Based on review of the map titled Lines of Equal Depth to Groundwater Spring 1999 published by the San Joaquin County Flood Control District and Water Conservation District(FCD&WCD),the estimated depth to ground water at the site is approximately 20 feet bsg; review of Lines of Equal Elevation of Groundwater Spring 1999 (FCD&WCD) shows the regional ground water flow t direction towards the northeast. However, review of recent ground water monitoring well data collected from monitoring wells at the site suggests a southwest ground water flow direction.Review of previous ground water monitoring at the site and historical depth to ground water maps (FCD&WCD) dating back to 1971 suggests that ground water depth near the site has fluctuated between 15 and 50 feet bsg. Ground water depth in wells at the site in September 2004 was approximately 22 feet bsg. Ground water flow direction at the site,determined from data collected in September 2004,was southwest. Advanced GeoEnvironmental,Inc. t