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12 June 2008 AGE-NC-07-1581 Page 6 of 17 designated the Sacramento and San Joaquin Valleys,which have been filled to the 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. Geologically,the area around the subject property generally consists of Holocene-aged flood-basin deposits of clay, silt, and sand. Miocene to Holocene age-units are located in the surrounding area. These deposits are heterogeneous mix of generally poorly sorted clay, silt, sand, and gravel with some beds of claystone, siltstone, sandstone, and conglomerate (Page, 1986). Most of the fresh ground water in the Central Valley is contained in the post-Eocene-aged continental rocks and deposits and in the Holocene-aged river deposits consisting of gravel, sand, silt,and minor amounts of clay.In general,these geologic materials comprise a major widespread aquifer extending hundreds of feet deep and occasionally containing individual confining layers. 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, which is approximately 15 miles west of subject property.The nearest surface water feature in the vicinity'of the property is the Calaveras River, located approximately 150 feet southeast of the property. 4.1. GROUNDWATER DESCRIPTION FOR THE GENERAL AREA The San Joaquin County Flood Control and Water Conservation District's Lines of Equal Depth to Ground Water Spring 1999 indicates the depth to groundwater is 90 feet or less. Groundwater flow (�•/� direction locally appears to be southeast, in the direction of the Calaveras River. Ground water was not encountered in the 42-inch percolation test hole on 26 December 2007. Based upon a review of well permit records at EHD by an AGE representative, the total depth of domestic water wells for the surrounding area was reported to be between 156-feet and 280-feet bsg. The well on the adjacent property was installed to a depth of 156 feet. 4.2. GROUND WATER CONTAMINATION IN THE AREA OF THE SITE land use for the parcel is agricultural in nature. There are The immediately adjacent and outlying p g potential ground water contamination issues associated with agricultural uses and local septic systems.A review of the California Department of Toxics and Substance Control(DTSC)Envirostor C Advanced GeoEnvironmcntal,Inc.