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Statement of Work (revised) Former Chevron Station No. 98632 575 W. Grant Line Road Tracy, California In response to the Request for Well Destruction letter received from the Central Valley Regional Water Quality Control Board on October 30, 2018 (attached), Arcadis, U.S., Inc. (Arcadis), plans to destroy the eight remaining groundwater monitoring wells at the site. Underground Service Alert of Southern California (USA) will be notified at least 48 hours prior to the commencement of field activities. Arcadis also retained a private utility locating company to identify and mark underground utilities to be avoided during planned subsurface activities. This geophysical survey will take place approximately one week before commencing well destruction activities. Well destruction Arcadis will oversee the destruction of the eight remaining on-site monitoring wells MW-1, MW-2, MW-3, MW-4, MW-5, MW-6A, MW-6B, and MW-7 (see attached boring logs). Arcadis will retain a drilling contractor with a C-57 license to perform the well abandonment activities and Arcadis will oversee the work under the supervision of a licensed Professional Geologist. The well will be gauged, and total depth confirmed per the corresponding boring log. The well box, well lid and collar will be removed from each well and will then be cleared with an air knife or hand auger to 8 feet below ground surface (bgs). Over-drill Method Wells MW-1, MW-3, MW-5, MW-6B, and MW-7 will be destroyed via over-drill method due to an insufficient annular seal. The annular seal on the wells referenced above were completed to less than 20 feet below ground surface (bgs). Wells will be over-drilled to final depth, and the void will be filled with a cement (95%)/bentonite (5%) grout followed by neat cement. Concrete will be applied from 1.5 feet bgs to the ground surface, dyed to match existing ground conditions. Blast Perforation Method Wells MW-2, MW-4 and MW-6A will be destroyed via blast perforation method due to utility conflicts. MW-2: Active electrical line is located 40 inches from well casing. MW-4: Active communications line is located 7 inches from well casing. MW-6A: Unknown metal conduit is located 6 inches from the well casing. A tremie pipe will be used to fill each well in one continuous operation from the bottom to the top of the well with a 95% neat cement/5% bentonite grout mixture or neat cement from bottom of the well to the top. (Any displaced groundwater will be captured and put into a DOT-approved drum for disposal.) The detonator cord will be placed in the well from 5 feet bgs to approximately 20 feet bgs. The charge will be detonated. The well casing will be cut at 2.5 feet bgs either before the grout and charges are installed in the well or afterwards but before the grout has a chance to harden. Additional grout or neat cement will be used to fill the well as necessary. Concrete will be applied from 1.5 feet bgs to ground surface, dyed to match existing ground conditions.