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Statement of Work 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. Wells MW-1, MW-2, MW-3, MW-4, MW-6A, and MW-7 will be destroyed via overdrill 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 overdrilled 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. Wells MW-5 and MW-6B have an annular seal that is greater than 20 feet bgs and therefore will be destroyed utilizing pressure grout methodology. The well box ring, lid, top 5 feet of well casing, and the surrounding well pad will be removed. Wells MW-5 and MW-6B will be pressure-grouted using a cement (95%)/bentonite (5%) grout. The grout will be delivered from the bottom of the well to the top using a tremie pipe. Once filled with grout, the well head will be sealed and slowly pressurized up to 25 pounds per square inch (psi). This pressure will be maintained for approximately 15 minutes to allow the grout to set. Following pressurization, additional grout will be added as needed until the well no longer accepts the material. The well will be pressure grouted from the bottom to 1.5 feet below ground surface. Concrete will be applied from 1.5 feet bgs to the ground surface, dyed to match existing ground conditions. Grout calculations The estimated cement (95%)/bentonite (5%) grout volume for overdrilled wells MW-1, MW-2, MW-3, MW-4, MW-6A, and MW-7 is 56 gallons each. The estimated cement (95%)/bentonite (5%) grout volume for pressure grouted wells MW-5 and MW-6B is 53 gallons and 56 gallons, respectively.