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October 9, 2017 Reference No. 632277D <br />Mr. Alan M. Buehler, P.G. <br />Central Valley Regional Water Quality Control Board (RWQCB) <br />11020 Sun Center Drive, Suite 200 <br />Rancho Cordova, California 95670 6114 <br />Re: Work Plan Second Addendum <br />Former Chevron Service Station 98632 <br />575 West Grant Line Road <br />Tracy, California <br />RWQCB Case #390842 <br />Dear Mr. Buehler: <br />GHD is submitting this Work Plan Second Addendum for the Former Chevron Service Station 98632 <br />located at 575 West Grant Line Road in Tracy, California (Figure 1) on behalf of Chevron Environmental <br />Management Company (Chevron). Conestoga-Rovers and Associates, Inc.'s (CRA) December 22, 2014 <br />Site Assessment Work Plan (Work Plan) proposed to advance two soil borings to investigate hydrocarbon <br />concentrations in soil in the vicinity of the former gasoline underground storage tanks (USTs) and <br />dispenser islands for comparison to LTCP criteria. In a letter dated February 19, 2015, the San Joaquin <br />County Environmental Health Department (SJCEHD) disagreed that two soil borings were sufficient to <br />adequately characterize the distribution of residual hydrocarbon impact. In response, CRA submitted the <br />April 21, 2015 Site Assessment Work Plan Addendum (Work Plan Addendum), adding a third soil boring <br />to the proposed scope of work. This work plan addendum was accepted by SJCEHD in a letter dated <br />June 15, 2015. On July 15, 2015, Chevron was notified that the UST Case had been transferred to <br />RWQCB. On June 13, 2017 representatives from Chevron, GHD, and the RWQCB met via teleconference <br />to discuss the path to case closure. In a letter dated July 31, 2017, the RWQCB requested a work plan <br />second addendum to collect shallow soil samples in the vicinity of the former used-oil tank and soil <br />samples outside of the hydrocarbon impacted area to establish background metals concentrations. <br />Regulatory correspondence is included as Attachment A. The site background, proposed work scope, <br />and anticipated schedule are presented below. <br />1. Site Background <br />1.1 Site Description <br />The site is a former Chevron service station located on the northeast corner of Tracy Boulevard and West <br />Grant Line Road in a mixed commercial and residential area of Tracy, California (Figure 1). Former <br />station facilities included a station building and service bay, three 10,000-gallon USTs containing <br />unleaded gasoline, one 1,000-gallon used-oil UST, one oil/water separator (sump), and two semi- <br />hydraulic hoists (Figure 2). The fiberglass fuel USTs were installed in 1984 when an unknown number of <br />GHD <br />10969 Trade Center Drive Suite 107 Rancho Cordova California 95670 USA <br />T 916 889 8900 F 916 889 8999 W www.ghd.com