ARCHIVED REPORTS_XR0012651 - Laserfiche WebLink

Home Browse Search

Work Plan Ground Water Investigation Program Ragu Foods, Inc. Stockton, California 1.0 Introduction The following work plan presents a ground water investigation program designed by Roy F. Weston, Inc. (WESTON) to assess the extent of diesel residues at the Ragu Foods, Inc. , facility (RAGU) located at 1400 Waterloo Road, Stockton, CA. The plan addresses the installation and sampling of three shallow ground water wells placed around a former underground diesel tank site. The tank as well as the soils in the immediate vi:inity of the tank were removed and the resulting hole was backfilled in 1987. Al]. of the work discussed in this work plan will be conducted under the supervision of a Registered Geologist. 2.0 Weil Siting Three locations have been selected for the installation of the monitoring wells, as shown on Figure I. The orientation of the wells at 120 degrees apart should serve both to define a site specific ground water gradient and provide water quality informa- tion upgradient and downgradient of the former diesel tank site. The wells will be located about 60 feet from the former tank site in areas that should provide some security from heavy truck traffic. If, after completion, development and sampling of the newly installed monitor wells, the site specific gradient as determined from these wells indicates placement of the wells is inadequate to effectively monitor the site, it may be necessary to install an additional monitor well at the site. Specific recommendations regarding a possible fourth monitoring well will be addressed in the report submitted following completion of the work. 2.1 Well installation As the anticipated depth to water is no more than 40 feet below ground surface (BGS) , the wells will be installed using hollow stem auger drilling techniques. The well casing and screen will be made from nominal 4" diameter flush threaded P.V.C. pipe, with a 3u foot screened interval placed 20 feet into the uppermost saturated zone and 10 feet above the saturated zone. This plan may require modification in the event a clay zone is observed during drilling. There is no intention of penetrating a continu- ous clay layer. The gravel pack for the wells will utilize clean silica sand placed around the well screen to a height. of 3 feet above the top of the well screen. A one foot thick bentonite --- -- - - -- -----------:-------------sea- ---wi-1-1--be-placed-above-the-sarid__pack-and-the well annulus will then be sealed to the surface with a 4% bentonite cement grout.