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amec <br /> SITE INVESTIGATION AND AIR SPARGING PILOT TEST WORK PLAN <br /> Caltrans Stockton Yard Maintenance Station <br /> 1604 South B Street <br /> Stockton, California <br /> 1.0 INTRODUCTION <br /> On behalf of the California Department of Transportation (Caltrans), AMEC Geomatrix (AMSC) <br /> has prepared this Site Investigation and Air Sparging Pilot Test Work Plan (work plan)for the <br /> Caltrans Stockton Yard Maintenance Station located at 1604 South B Street in Stockton, <br /> California (the Site). Petroleum hydrocarbons were detected in the site subsurface in 1989 <br /> during removal of an underground storage tank(UST) system. In response, Caltrans has <br /> completed several investigations at the Site between 1992 and 2009 under the oversight of <br /> San Joaquin County Environmental Health Division (SJCEHD). Although the extent of <br /> rpetroleum hydrocarbons in groundwater at the Site has been laterally and vertically defined, , <br /> the location and concentration of petroleum hydrocarbons in the source area is not well <br /> r determined. <br /> LThe current approach for remediation at the Site includes installation of soil vapor extraction <br /> (SVE)/air sparge (AS) system to remediate the remaining petroleum hydrocarbon impacts in <br /> the source"area. Prior to completing the design of the SVEIAS system, the extent of impacts <br /> in the source area must be known so that remediation wells can be properly located. <br /> Additionally, Site specific parameters for AS must be estimated before a design can be.. <br /> completed. The purpose of this work plan is to outline the field work required to characterize <br /> the source area, install AS pilot test wells, and to conduct an AS pilot test. <br /> 1.1 DOCUMENT ORGANIZATION <br /> LFollowing this introduction, this work plan is organized into the following sections: <br /> • Section 2 presents limited background information and summarizes the relevant <br /> results of recent investigations and remediation activities conducted at the Site. <br /> • Section 3 describes the scope of work for the source area characterization and well <br /> installation activities. <br /> ` • Section 4 describes the rationale and the approach for the AS pilot test. <br /> i..� • Section 5 specifies design parameters and evaluations to be reported after <br /> completion of the test. <br /> AMEC Geomatrix, Inc. <br /> P:\Project\14000s\14443_Caltrans\TO 10\11000_PLAWAS WP March 2010WS WP.doc 1 <br /> i� <br />