ARCHIVED REPORTS_XR0003159 - Laserfiche WebLink

Home Browse Search

F - - Site Background Information R M B. GARAGE (ERARDI VENTURES) ' 715 North Hunter Street, Stockton, California REGIONAL GEOLOGIC/HYDROGEOLOGIC SETTING ' The site is located within the southern San Joaquin Valley which comprises part of the Great Valley geomorphic province of California The San Joaquin Valley is formed by the Great Valley ' geosyncline, which is a large, elongate, northwest-trending asymmetrical structural trough(basin) It is bordered by the Coast Ranges to the west, the Klamath Mountains and Cascade Range to the north, and the Sierra Nevada to the east This trough has been filled with sediments derived from ' both marine and continental sources Thickness of the sedimentary fill ranges from thin veneers along the valley edges to more than 20,000 feet in the south central portion of the valley The sedimentary formations range in age with the older deposits being primarily marine in origin and the ' younger deposits being primarily continental Continental-derived sediments were primarily deposited in lacustrme,fluvial,and alluvial environments with sediment sources being the mountain ' ranges surrounding the valley(Olmsted and Davis, 196 1) The site is located on unconsolidated and semi-consolidated alluvium, lake,playa and terrace deposits of Quaternary age(California Division of Mines and Geology, 1977) ' The Modesto, Riverbank and Turlock Lake Formations and overlying Recent alluvium are the principal sources of domestic ground water in the 13,500-square mile San Joaquin Valley Ground Water Basin (Basin 5-22) Based on information obtained during drilling, ground water depth lie beneath the site is approximately 25 to 30 feet below surface grade (bsg) Based on information obtained from a nearby site(706 North El Dorado Street)the prevailing ground water flow direction ' in the vicinity of the site is inferred to be toward the northeast However, flow direction maybe both locally and seasonably variable ' SITE STRATIGRAPHY ' Between surface grade and approximately 12 feet bsg,the soil consisted of brown to yellow-brown and orange-brown clays, silty clays and clayey silts, with a thin, fine-sand lense at approximately 6 feet bsg Between 12 feet bsg and 50 feet bsg,the soil consisted of light brown to yellow/orange- brown clayey sands and silty sands, with the exception of a blue gray to brown clay to sandy clay layer at between approximately 23 feet bsg to 27 feet bsg From approximately 50 feet bsg to total depth of boring B5, the soil consisted of a gray, well graded medium to coarse sand with gravel ' SITE ASSESSMENT ACTIVITIES On 04 January 2002, four soil borings were advanced by Advanced GeoEnvironmental,Inc(AGE) ' at the site as part of the assessment related to the former USTs Soil probe borings B 1 through B4 were advanced vertically to depths of 40 feet bsg ' Advanced GeoEnviron mental,Inc 1