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01 September 1999 AGE-NC Project No 97-0301 ' Page 3 of 10 ' elongate, north-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 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 French Camp Slough located approximately 1,000 feet west of the site I25 GROUND WATER DEPTH AND GRADIENT ' Based on review of the Lines of Equal Depth to Groundwater Fall 1997 map 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 between 35 and 40 feet below surface grade (bsg) Review of the map Lines of Equal Elevation of Groundivatei Fall 1997(FCD&WCD) depicts the regional ground water flow direction to be toNN ards the northeast ' Based on data collected during the April 1999 investigation, depth to ground water was measured at approximately 37'/2 feet bsg in soil probe borings P-1 through P-4 3.0 SCOPE OF WORK Based on the results of the previous investigations and UST removal activities, g round water and sall at the site has been impacted The lateral and vertical extent of impacted soil and ground water ' must be determined prior to the initiation of remediation The assessment activities will consist of I Atli-anted Get Ens iron mental,Inc