Laserfiche WebLink
*MEMORANDUM <br /> CALIFORNIA REGIONAL WATER QUALITY CONTROL BOARD - CENTRAL VALLEY REGION <br /> 3443 Routier Road, Suite A Phone: (916) 361-5600 <br /> Sacramento, CA 95827-3098 ATSS Phone: 8495-5600 <br /> TO: Wendy L. CohenFROM: Philip S. Isorena <br /> Senior Engineer Associate Engineer <br /> DATE: 1 November 1993 SIGNATURE: &4 11 <br /> SUBJECT: HYDRAULIC OIL SUMP INVESTIGATION, LIBBEY-OWENS-FORD, <br /> LATHROP, SAN JOAQUIN COUNTY <br /> BACKGROUND <br /> A fast-track tunnel construction project will require excavation to a depth of approximately 12 feet <br /> below the existing floor level in the area of hydraulic lift sumps 1 and 2. Excavation of 14 to 16 <br /> feet below the existing floor level and dewatering will be necessary in the area approximately 50 <br /> feet east of Sump 1. The attached Figure 1 shows the locations of the proposed tunnel, two <br /> hydraulic oil aboveground tanks (ASTs) and sumps, completed and proposed boreholes, and extent <br /> of excavation. <br /> A 10 October 1993 preliminary investigation indicated the presence of hydraulic oil and total . <br /> petroleum hydrocarbons in the diesel range (TPHD) in the soils and separate phase petroleum <br /> hydrocarbons (SPPHC) identified as hydraulic oil on top of the ground water. All investigation and <br /> excavation of contaminated soils must be completed prior to construction which is scheduled to <br /> begin on 15 November 1993. <br /> WORK PLAN <br /> On 20 October 1993, Condor Earth Technologies, Inc. (Condor), LOF's consultant, submitted a <br /> report on the preliminary investigation and a work plan for investigation and remediation of the soil <br /> and ground water contamination in the hydraulic lifts area. Also on this day I discussed with Mr. <br /> David Meade of Condor my comments on the work plan. He agreed to all my comments which are <br /> presented below. <br /> 1. The work plan proposes to install at least one extraction well (EW) to recover SPPHC prior to <br /> tunnel construction and at least three monitoring wells (MWs) after tunnel construction. <br /> I told Mr. Meade that the EW(s) should be placed in the center of the plume(s) to optimize <br /> recovery of the SPPHC. I also required that the MWs be placed prior to any dewatering to <br /> ascertain primarily whether dewatering might spread the contamination and secondarily <br /> whether the EWs are capturing the plume. Long-term remediation also should be considered <br /> when placing the extraction and monitoring wells. <br />