ARCHIVED REPORTS_XR0010165 - Laserfiche WebLink

Home Browse Search

21 August 2000 AGE-NC Project No 97-0343 Page 3 of 9 2 4 REGIONAL GEOLOGIC 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 boundanes 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 origin The northern and southern portions of the Great Valley Province have been designated the Sacramento and San Joaquin Valleys, respectively 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 Stockton Diverting Canal located approximately 300 feet north of the site 2 5 GROUND WATER DEPTH AND GRADIENT Based upon data collected from monitoring wells on site in July 2000, ground water was at a depth of approximately 44 feet bsg and flowing toward th mast nder an average gradient of 0 001 ft/ft , however, based on data collected from the monitoring wells on site in March 2000, ground water was at a depth of approximately 33 feet bsg and flowed toward the sbutgwest under an average gradient of 0 037 ft/ft Flow directions maybe both locally and seasonably variable The uppermost ground water flows in an unconfined aquifer With increasing depth, the aquifer becomes semi- confined, due to the presence of fine-grained strata The Stockton Diverting Canal is located adjacent to the site and usually contains little water and has not appeared to have a significant effect upon ground water depth or flow direction in the area, however the canal could be the cause of the significant fluctuation in ground water flow direction and depth at the site 3.0. SCOPE OF WORK Based on the data accumulated from preliminary site assessment activities and quarterly monitoring AGE proposes to collect soil and ground water samples to further assess the lateral and vertical • Advanced GeoEnvironmental,Inc