ARCHIVED REPORTS_SOIL AND GROUNDWATER INVESTIGATION REPORT 2008

Home Browse Search

Soil and Groundwater Investigation Report Vernalis Offsite June 2008 Vernalis Offsite is comprised of a portion of two parcels (San Joaquin County APN 255-160-016 and ' Stanislaus APN 016-002-007)owned by the Bogetti family and located down gradient from the pump station on the east side of Highway 33. These parcels are used for agricultural purposes (SAIL, 2007). 2.2 HISTORICAL AND EXISTING PIPELINE FACILITIES From 1902 to 1935, Standard Oil (predecessor to Chevron)operated the Vernalis Pump Station,which was part of the former OVP system that transported heated crude oil from San Joaquin Valley oil fields in ' Bakersfield to a refinery in Richmond, California. The OVP was located along the northeastern side of the former Vernalis Pump Station and parallel to the Union Pacific Rail Road(UPRR) right of way (ROW) and Highway 33. Historical features at the former Vernalis Pump Station included a boiler house, a pump house, a sump,an incinerator, a rubbish pit,cottages, and three bulk-storage tanks with secondary containment structures. These surface structures were located on the Arcos property. Several pipelines entered the pump station from the east corner of the Arcos property, conveying flows to the heater house and exiting to the north across the Bellini property. The former Tidewater Associated Oil Company(TAOC) Ohm Pump Station is located immediately southeast of the Arcos property. The TAOC pipeline was located on the east side of Highway 33 within the UPRR ROW. A 1995 environmental site assessment documented that the former TAOC Ohm Pump Station was owned by Vernalis Enviropur-West and was used for bulk storage of petroleum and oil ' products (Geological Technics, 1995). The TAOC pipeline system was constructed in 1907 and transmitted heated crude oil from Bakersfield to the Bay Area;the system also utilized a crude oil cutter stock from the Coalinga area to a Bay Area refinery. The TAOC pipelines were abandoned in the 1970s. Kinder Morgan Energy Partners,L.P. (KM)currently maintains a high-pressure,petroleum-product pipeline that reportedly transports gasoline,jet fuel, and diesel. The KM pipeline is located within the UPRR ROW. A previous environmental site assessment documented that the KM pipeline was installed approximately 4 to 5 feet below ground surface(bgs)during 1985, is constructed of 0.25 inch-thick wrapped steel, and was under the control of a subsidiary of Southern Pacific Pipeline Company (Geological Technics, 1995). ' 2.3 EXISTING AND PLANNED DEVELOPMENT Vernalis Offsite is located in a predominantly agricultural area and is bordered by tree crops to the north, ' south,and east and the West Stanislaus Irrigation District canal to the west. Highway 33 and the UPRR ROW are located beyond the irrigation canal. Several light-industrial facilities are located along Highway 33 within one half mile of Vernalis Offsite.No plans for new development are known for Vernalis Offsite or the former Vernalis Pump Station. 2.4 HYDROGEOLOGIC SETTING The site is situated within the Central Valley Physiographic Province of California,has a relatively flat topography that slopes gently downward to the northeast, and is at approximately 107 feet above mean sea level. Groundwater in the upper water-bearing zone flows in a northeasterly direction at a gradient of 0.001 feet per foot(ft/ft) and is hydraulically controlled by low-permeability,unconsolidated sediments. Depth to groundwater near the site varies from 20 to 40 feet bgs. Soils appear to be fine-grained unconsolidated sediments,consisting mainly of lean clays and silts and clayey and silty sands, with smaller quantities of poorly graded sand and gravel(SAIC, 2006). 2 From Science to Solutions