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• •Corporation <br /> 1326 North Market Boulevard <br /> Sacramento, CA 958341912 <br /> Tel 916.928.3300 <br /> the�� �rO�� 'i/ Fax. 916.928.3341 <br /> 9 Q. A A1ember of The IT GrouP <br /> April 9, 2001 <br /> Project 812717 <br /> Ms. Devra Lewis <br /> California Regional Water Quality Control Board <br /> Central Valley Region <br /> 3443 Routier Road, Suite A <br /> Sacramento, California 95827-3003 <br /> Re: Response to Review of the Groundwater Investigation Report, Stockton Terminals <br /> Technical Committee, Port of Stockton Fuel Terminals, San Joaquin County, Regional <br /> Water Quality Control Board, 12 March 2001 <br /> Dear Ms. Lewis: <br /> IT Corporation (IT), on behalf of the Stockton Terminals Technical Committee (STTC), would <br /> like to provide the following responses to your comments on the Groundwater Investigation <br /> Report that was submitted to the Regional Water Quality Control Board (RWQCB) on January <br /> 23,2001. IT will respond to each of the comments in the order they were presented in your letter. <br /> A work plan for the installation of additional monitoring wells at the site will be submitted to the <br /> RWQCB under a separate cover by April 9, 2001. IT is currently completing a Feasibility Study <br /> (FS)for the STTC facilities that will be submitted to the RWQCB on May 5, 2001. <br /> Comments and Responses <br /> 1. The Report states groundwater zone D starts at approximately 80 feet below ground surface <br /> (bgs). The cross sections A-A', B-B', and C-C'provide information to 100 feet bgs but do not <br /> show a D-Zone. Cross section D-D' shows the D-Zone at approximately 95 feet bgs. An <br /> Explanation is needed for this discrepancy. <br /> Definition of the D-Zone sands are based on correlation to Harding Lawson Associates <br /> interpretation of strata beneath the ARCO terminal (October 90 and November 91). Sands <br /> interpreted to be D-Zone strata underlie continuous silt to clay that separates the deeper sands <br /> from those in the upper C-Zone. The D-Zone sands are thin and discontinuous as identified <br /> in boreholes, may actually be isolated sands within the lower C-Zone, and may not be a <br /> distinct aquifer. <br /> As shown on the various cross sections, the depth to the upper and lower boundaries of the <br /> water-bearing zones varies considerably across the site. The sedimentary deposits beneath <br /> the site are inferred to have been deposited by fluvial action. This type of depositional <br /> environment is characterized by localized scouring and deposition that results in irregular <br /> upper surfaces on individual units. <br /> C:WY Documents\ProiectsPon of Stm tton\CPT HP Study\Response to Comments.doc IT CORPORATION <br /> 812717 <br />