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California Rewnal Water Quality C*htrol Board <br /> Central Valley Region 5� <br /> Robert Schneider,Chair <br /> Alan C.Lloyd Ph.D. Sacramento Main Office ^r��=j��jl f( 'nold Schwarzenegger <br /> Secretary for Internet Address: http://www.waterbouds.ca.gov/centralval lL�� 1 u v Governor <br /> Environmental 11020 Sun Center Drive!4200 Rancho Cordova,CA 9567061 4 <br /> Protection Phone(916)464-3291 Fax(916)4644797 <br /> FEB 2 12006 <br /> 16 February 2006 ENVIRONMENT HEALTH <br /> PERMIT/SERVICES <br /> Mr. Thomas Bauhs Ms. Kitty Walker <br /> Chevron Environmental Management Company Stockton Department of Housing & Redevelopment <br /> P.O. Box 6012 305 North EI Dorado Street, Suite 200 <br /> San Ramon, CA 94583-0904 Stockton, CA 95202. <br /> WORK PLAN REVIEW, SOUTH SHORE PARCEL 2A,666 WEST WEBER AVENUE, <br /> STOCKTON, SAN JOAQUIN COUNTY <br /> Staff of the Central Valley Regional Water Quality Control Board(Central Valley Water Board) <br /> reviewed the 4 January 2006 Work Plan for Additional DPE Feasibility Testing and Expanding <br /> Remedial System Installation (Work Plan) submitted by SECOR International Incorporated (SECOR) <br /> on behalf of the L&M Operable Unit, 666 West Weber Avenue, Stockton (site). The site is a portion of <br /> Area 2A belonging to the City of Stockton Redevelopment Agency (RDA) as identified within the City's <br /> 13 September 2000 Environmental Master Plan. Chevron Environmental Management Company <br /> (Chevron) is conducting cleanup at the site on behalf of itself and any and all the other responsible <br /> parties. The scope of work contained in the Work Plan states,"The objective of this work plan.is to <br /> present a plan for performing feasibility testing using the existing and proposed DPE [dual phase <br /> extraction] wells and deeper monitoring well MW-40. The installation of seven new piezometer wells is <br /> proposed to provide additional data collection points during the feasibility testing. This work plan also <br /> presents a plan of action for optimization of the existing DPE system and implementation of separate <br /> SVE equipment to enhance remediation beneath the undeveloped portion of the L&M OU and beneath <br /> the Delta View Apartments." Central Valley Water Board staff have the following comments on the <br /> Work Plan. <br /> 1. A feasibility test is usually completed prior to the implementation of a remedial measure in an <br /> effort to select the most appropriate remedial measure. Further, during the feasibility phase, <br /> enough information is typically collected to design the optimal treatment system. Since we are <br /> revisiting the feasibility phase of site remediation other treatment methods should be considered <br /> and other data collected. For example, sampling and analysis within the Work Plan should <br /> evaluate in-situ biodegradation and include additional targeted groundwater analysis for those <br /> parameters. <br /> 2. It appears,that six of the seven piezometers, which are intended to gather data to model the <br /> unimproved area of the L&M OU will pierce the vapor barrier,created by the placement of plastic <br /> sheeting in the excavation at about 10 feet below ground surface. The Soil Vapor Extraction <br /> (SVE)system may be short-circuited by the installation of these piezometers. Therefore,once <br /> the short-term tests are completed, Chevron should plan to properly destroy the piezometers and <br /> restore the efficiency of the SVE system. <br /> California Environmental Protection Agency <br /> 0 Recycled Paper <br />