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Unocal/Wards - 2— 26 February 2001 <br /> 5400 and 5606 Pacific Avenue, Stockton <br /> were identified approximately 2,500 feet south of the proposed well site. Groundwater contamination has <br /> been characterized at these three sites, and one of the sites has started remediation. Two municipal wells <br /> were identified outside the 2,500-foot radius, north of the proposed well; however, it was not determined if <br /> these municipal wells are active at this time. The results of this added investigation show that sources of <br /> known groundwater contamination and groundwater extraction are greater than 2,000 feet from the proposed <br /> well site, and the proposed well should not be impacted by this contamination. <br /> In December 2000,EAI submitted the Corrective Action Feasibility Study, Permanent Long Term Irrigation <br /> Water Source for San Joaquin Delta College, Claimant—Montgomery Ward Auto Service Center, 5400 <br /> Pacific Avenue, Stockton, Cleanup and Abatement Order No. 5-00-707 to the UST Cleanup Fund. This <br /> feasibility study evaluated wellhead treatment, connection to City of Stockton water supply, and well <br /> replacement. Well replacement was identified as the most cost effective alternative. <br /> Based on the results of the test boring, investigation of current and former USTs,proximity to existing water <br /> supply wells, and water supply alternatives evaluated,EAI proposes to install an irrigation well to provide a <br /> permanent long-term irrigation water supply to Delta College. The proposed irrigation well will be drilled <br /> to 370 feet bgs, screened from 320 to 370 feet, and constructed with a cement grout seal from ground <br /> surface to 300 feet bgs. Board staff believes the proposed irrigation well is appropriate and necessary to <br /> provide the Delta College with a replacement irrigation water supply, and the proposed replacement <br /> irrigation well meets the requirements of Order No. 6 in C&A Order No. 5-00-707. <br /> In the 13 October 2000 Problem Assessment Report,EAI stated that RIW operation has drawn contaminants <br /> from beneath the Unocal/Wards sites to the RIW. We are also concerned for cross-contamination of deeper <br /> water bearing zones due to the RIW being screened at various intervals starting at 40 feet, and ending at <br /> 322 feet. Therefore, in conjunction with providing a replacement irrigation well for the Delta College, <br /> Unocal/Wards must also submit a plan of work to modify or destroy the RIW to address the issue of cross- <br /> contamination. By 26 March 2001, submit a plan of work to modify or destroy the RIW,with-the <br /> understanding that an extraction well may be necessary near the RIW at a later time. <br /> Please notify Mike Infurna at San Joaquin County Environmental Health(209)468-3454 and myself at least <br /> two business days prior to any site work or sampling. If you have any questions or comments, call me at <br /> (916'))255-3115. <br /> ` <br /> rr/ )14 <br /> ^_1V <br /> Marty Hartzell <br /> Associate Engineering Geologist <br /> cc: Mr. Mark Owens,UST Cleanup Fund, SWRCB, Sacramento <br /> Mr.Mike Infurna, San Joaquin County Environmental Health Division, Stockton <br /> Mr. Steven Bright,Environmental Audit, Incorporated,Placentia <br /> Mr. Bob Yribarren, San Joaquin Delta College, Stockton <br />