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• MEMORANDUM • <br /> CALIFORNIA REGIONAL WATER QUALITY CONTROL BOARD - CENTRAL VALLEY REGION <br /> 3443 Routier Road, Suite A <br /> Sacramento, CA 95827-3098 Phone: (916) 361-5600 <br /> ATSS Phone: 8495-5600 <br /> TO: Antonia K. J. VorsterA 4V FROM: Camilla Williams <br /> Senior WRC Engineer Engineering Geologist <br /> DATE: 7 November 1991 SIGNATURE: ��%7 � ✓P� <br /> SUBJECT: REVIEW OF WORK PLAN FOR UNDERGROUND STORAGE TANK INVESTIGATION, DEFENSE <br /> DISTRIBUTION REGION WEST (DDRW), SNARPE SITE, SAN JOAQUIN COUNTY <br /> I have reviewed the Work Plan for Underground Storage Tank Investigation submitted <br /> on 2 October 1991 by the U. S. Army Toxic and Hazardous Materials Agency (USATHAMA) and <br /> prepared by Environmental Science and Engineering (ESE) for the DDRW. Sharpe Site <br /> (Sharpe) . The strengths of this report were the tables and figures which summarized <br /> of the previous investigations performed at each of the tank sites. The summary tables <br /> helped to expedite the review of the Work Plan. <br /> On 15 and 18 October 1991, I discussed my concerns on the Work Plan with Mr. Craig <br /> MacPhee of USATHAMA. It is my understanding that not all of the tanks can be <br /> investigated at this time with the available funding and that future necessary tank <br /> investigations must be funded through a separate mechanism by Sharpe. USATHAMA has <br /> taken the approach to try to do a "complete" investigation on the selected tank sites <br /> rather than investigate all of the tank sites to fill data gaps. There are merits to <br /> both investigative approaches. However, ultimately Sharpe will need to investigate <br /> each tank site to determine if there have been any leaks, if ground water has been <br /> impacted and if soil and/or ground water remediation is necessary. <br /> My other two major concerns with the Work Plan were the placement of the six monitor <br /> wells and the cleanup levels. The placement of the wells was resolved with my <br /> discussions with Mr. MacPhee. It is my understanding that the some of the wells will <br /> be relocated based on my recommendations. My other outstanding concern is the proposed <br /> soil cleanup levels for diesel at 100 milligrams per liter (mg/kg) and for gasoline at <br /> 10 mg/kg. Because the ground water table at the site may be as shallow as five feet <br /> below some of the UGTs, these concentrations may not be acceptable. The existing soil <br /> data summarized in the Plan did not include the depths of the samples. These proposed <br /> levels may not be acceptable because if left in-place, these concentrations may pose <br /> a threat to water quality. The analytical data developed in this investigation should <br /> help to determine an acceptable cleanup level for these contaminants. <br /> Below are my detailed comments on the Plan. <br /> Page 2-1 . The Plan states that the California Regional Water Quality Control Board <br /> (CRWQCB) published the Leaking Underground Fuel Tanks (LUFT) Manual . The <br /> LUFT Manual was published by the State Water Resources Control Board <br /> (State Board) and not the CRWQCB. <br /> The LUFT Manual is to be used as guidance for cleanups of contaminated <br /> soils only. The LUFT Manual presents several different approaches to <br /> determining the cleanup level for the soils. The LUFT Manual is not to be <br /> used if it is determined that ground water has been impacted by the <br /> leaking underground tank (UGT) . The Central Valley Regional Board UGT <br /> staff recommend that the Tri-Regional Board Staff Recommendations for <br />