Laserfiche WebLink
Ground Water Extraction Feasibility Pilot Test DEC 19 Z90a <br /> CHAPIN BROTHERS, INC. <br /> 1766 Monte Diablo Avenue, Stockton, California ENVIRONMENT HEALTH <br /> PERMIT/SERVICES <br /> At the request of Mr Russell Chapin,Advanced GeoEnvironmental, Inc (AGE) has prepared the <br /> enclosed work plan for 1766 Monte Diablo Avenue, Stockton, California (the site) The location of <br /> the site and its surroundings are illustrated in Figure 1 Structures, well locations and proposed <br /> boring locations are illustrated in Figure 2 The scope of work includes the installation a ground <br /> water elevation monitoring points and performance of ground water extraction pilot tests <br /> 10. BACKGROUND <br /> Site history and findings from previous investigations and monitoring events at the site are detailed <br /> in the Corrective Action Plan (CAP) and the quarterly reports prepared by AGE This scope of work <br /> was directed by the PHS-EHD verbally during a meeting conducted on 05 April 2000 <br /> Investigation activities will be performed in accordance with guidelines for investigation of <br /> underground storage tank (UST) sites established by the Central Valley Regional Water Quality <br /> Control Board (CVRWQCB) <br /> A soil vapor extraction / in-situ air-sparging system has been installed and operated at the site to <br /> remediate hydrocarbon-impacted soil and ground water Over the course of the remediation rising <br /> ground water elevation has submerged a significant portion of contaminated soil below the ground <br /> water table and capillary fringe <br /> Under this condition, hydrocarbon-impacted ground water has remained and the overall influence <br /> of the IAS system has demonstrated diminishing effectiveness at reduction of dissolved <br /> hydrocarbons Areas in the eastern portion of the site and at the northwest corner of the site have not <br /> demonstrated a sustained reduction of dissolved hydrocarbons Ground water has remained <br /> impacted <br /> A pump test conducted at the site in 1994 could only maintain a pumping rate of 0 25 gallons per <br /> minute(reported by Science& Engineering Analysis Corporation SEACOR)in Problem Assessment <br /> Report, dated 22 July 1994) SEACOR reported that the ground water-bearing zone exhibits low <br /> hydraulic conductivity, but presented no calculations SEACOR recommended an additional ground <br /> water extraction test <br /> 2 0. SCOPE,OF WORK <br /> The scope of the work includes installation of three temporary ground water depth/elevation <br /> • monttoring points, performance of two ground water extraction pump tests collection and analysis <br /> of grab water samples to assess the impacted media <br />