SITE INFORMATION AND CORRESPONDENCE

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. �..• MEMORANDUM CALIFORNIA REGIONAL WATER QUALITY CONTROL BOARD - CENTRAL VALLEY REGION 3443 Routier Road, Suite A Phone: (916) 361-5600 Sacramento, CA 95827-3098 ATSS Phone: 8-495-5600 TO: Wendy L. Cohen FROM: Philip S. Isorena Senior Engineer Sanitary Engineering Associate DATE: 20 July 1992 SIGNATURE: . ;k' ,J. SUBJECT: SITE STATUS REVIEW OF TOWER PARK MARINA, SAN JOAQUIN COUNTY I have reviewed the Site Assessment Workplan, Tower Park Marina, Law Environmental Project No. 31-1548, dated 3 December 1991, and Project Status and Resubmittal of Site Assessment Workplan, Tower Park Marina, Law Environmental Project No. 31-1548, dated 12 May 1992. The documents report the site background, work conducted to date, and proposed work. Background Tower Park Marina is located at 14900 West Highway 12 in Lodi, San Joaquin County near Little Potato Slough. The marina has a restaurant, cam ground, trailer park, and boat storage docks. Six aboveground storage tanks (ASTs� for petroleum storage were replaced in 1991. During drilling of one of the pylon holes for the concrete pad for the new tanks, petroleum product was encountered. An investigation was conducted which discovered free product in a corrugated metal pipe and a transite pipe, and leaks in the fuel lines, dispensers, and manifold. A subsequent investigation included soil sampling beneath trenches in which fuel lines were replaced, and soil gas sampling. The soil sample results show low levels of TPH (1 to 150 mg/kg) and BTEX (0.005 to 16 mg/kg). However, the soil gas isoconcentration map shows significant contamination (up to 40,000 ppm of TPH) in the soil gas. The revised site assessment work plan proposes to sample five shallow borings and install five monitoring wells. My comments on the two reports follow. Initial Site Assessment Work Plan 1. The work plan states that the corrugated metal pipe which contained free product was removed. It is not clear if the entire length of the pipe was identified and removed. 2. A transite pipe containing free product also was discovered, but it is not clear if its entire length was identified and removed. Its location is not plotted on the site map. 3. The work plan states, "The diesel pipe from the manifold to the docks appeared to be leaking at a location approximately five feet west of the manifold". This statement is speculative. It is not stated whether or not the leak was confirmed, and if so, whether the line was replaced. Also, a more accurate description of the leak is five feet northwest of the manifold. 4. The rationale for samples taken two feet below the piping trenches and the proposed depth of 15 feet at hot spots was not provided. The depth of the trench bottom was not stated in the work plan. No provision is made to determine the zero line of contamination in the soil vertically.