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GROUND WATER REMEDIATION Based on an EHD office meeting conducted on 05 April 2000 the EHD and the Central Valley Regional Water Quality Control Board (CVRWQCB) verbally agreed on the use of ground water extraction and treatment to mitigate the site As note above an SVE/IAS system has been installed and operated at the site to remediate hydrocarbon-impacted soil and ground water Over the course of the remediation rising ground water elevation has submerged a significant portion of contaminated soil below the ground water table and capillary fringe Under this condition,hydrocarbon-impacted ground water has remained and the overall influence of the IAS system has demonstrated diminishing effectiveness at reduction of dissolved hydrocarbons Areas In the eastern portion of the site and at the northwest corner of the site have not demonstrated a sustained reduction of dissolved hydrocarbons Ground water has remained impacted The implications from the set of March 2001 aquifer ground water extraction tests were the following The ground water table occurred within the screened interval of the well and the most likely source of the extracted ground water was from the highly permeable sand, encountered from 20 feet to 30 feet bsg Based on the ground water aquifer pumping test results, AGE recommended remediation by extracting petroleum-impacted ground water from a network of wells,at approximately 5 GPM total flow Based on the site's estimated radius of influence of at least 35 feet and site specific aquifer characteristics inferred from the pumping test,AGE believed that ground water extraction from four on site wells and three proposed installed ground water extraction wells will effectively stabilize the ground water plume and inhibit further migration of petroleum-impacted ground water off-site, further reducing the overall mass of dissolved hydrocarbons at the site Extracted ground water was to be treated through an on-site ground water pump-and-treat system The ground water pump and treat system would utilize granular activated carbon (GAC) to address TPH-g, and BTEX in extracted ground water Following treatment, water could then be discharged into the City of Stockton under a Municipal Utility District penult INSTALLATION OF GROUND WATER RECOVERY WELLS Between December 2001 and March 2002, three ground water recovery wells, a ground water treatment system and associated piping were installed at the site Ground water remediation system installation and operation were performed in accordance with procedures described In the approved Remedial Action Work Plan Addendum, dated 28 June 2001 Between 21 and 22 December 2001,three soil borings were advanced using a truck-mounted CME 75-HT drill rig equipped with continuous flight 12-inch augers The soil borings were advanced to a depth of 30 feet bsg Sort borings EW I, EW-2 and EW-3 were single-completed as groundwater extraction wells utilizing a schedule 40, 6-inch diameter blank polyvinylchloride(PVC)well casing and a perforated, 6-inch diameter PVC well casing (0 020-inch slot) The wells was installed by placing the PVC well casing assembly through the hollow stem of the augers to the total depth of the boring The augers were incrementally raised as filter pack material consisting of a 50150 blend of fine Advanced GeoEnvironmental,Inc