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Remediation Well Installation Work Plan New West Flag City Facility <br /> ' August 7 2008 6437 W. Banner Street, Lodi, California <br /> ' Groundwater monitoring and remediation system operation and maintenance continues on an <br /> ongoing basis. A more complete Site Background is included in Attachment A. <br /> 2.0 GEOLOGY AND HYDROLOGY <br /> ' The Site is located in the San Joaquin Valley Groundwater Basin (Basin 5-22). The Site is <br /> located within the Great Valley Syncline, a northwest trending synclinal trough. The Great <br /> ' Valley Syncline is situated between the Sierra Nevada to the east and the Coastal Ranges to the <br /> west (Geology of California, Norris & Webb). Based on previous soil investigation activities at <br /> ' the Site, the subsurface consist primarily of interbedded sediments such as silty sands, clayey <br /> sands, sands, sandy silts, and silt to a depth of approximately 25 feet bgs. These sediments are <br /> underlain by medium dense, medium stiff, sandy silts, silts, and clayey sands from 30 to 40 feet <br /> ' bgs, 50 to 70 feet bgs, and 80 to 90 feet bgs. Medium dense, poorly sorted, very fine to fine <br /> sands were encountered from approximately 40 to 50 feet bgs and from 87 feet bgs to the total. <br /> ' depth explored (95 feet bgs). <br /> ' Groundwater encountered at the Site consists of an unconfined zone beginning at first water <br /> (currently approximately 15 feet bgs to approximately 25 feet bgs. Semi-confined water-bearing <br /> zones are present beginning approximately 40 feet bgs, 70 feet bgs, and 90 feet bgs. <br /> ' Historically, groundwater flow has been variable at the Site but is commonly to the southeast and <br /> to the east. Operation of the on-Site extraction well pumps has created a cone of depression in <br /> ' the A, B and C Zones. <br /> ' 3.0 SCOPE OF INVESTIGATION <br /> The proposed scope of work consists of installing six off-Site down-gradient groundwater <br /> ' extraction wells to expand the current Groundwater Extraction System and help clean up the <br /> Site. Proposed well locations are shown on Figure 2. <br /> 1 4.0 FIELD INVESTIGATION <br /> 4.1 PRELIMINARY FIELD ACTIVITIES <br /> ' Prior to initiating field activities, Closure Solutions will obtain the necessary drilling, <br /> encroachment, and access permits, prepare a Site-specific Health and Safety Plan (HASP) for the <br /> ' proposed work, bid out to three contractor's and clear the Site for subsurface utilities. The <br /> ' Page 5 of 9 <br />