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� California. T gional Water Quality Co `'q � IJ <br /> `_ � Central Valley Region <br /> Karl E. Longley,ScD,P.E.,Chair009 <br /> Linda S.Adams95670-6114*� �"'�� Arnold <br /> Secretary for 11020 Sun Center Drive 11200,Rancho Cordova,California warzenegger <br /> Phone(916)464-3291 •FAX(916)464-4645 )NNIENT HEALTH Sch <br /> Environmental http://www.waterboardsca.gov/centralvalley ENVIR SERVICES Governor <br /> Protection PER. M�iT1 <br /> 22 May 2009 <br /> Ms. Anne Conner <br /> Pacific Gas and Electric Company <br /> 375 N. Wiget Lane <br /> Walnut Creek, CA 94598 <br /> RESPONSE TO COMMENT LETTER AND REMEDIAL EXCAVATION WORK PLAN, PG&E <br /> FRENCH CAMP GENERAL CONSTRUCTION YARD, FRENCH CAMP, SAN JOAQUIN <br /> COUNTY - <br /> California Regional Water Quality Control Board, Central Valley Region (Central Valley Water <br /> Board) staff reviewed the following documents: <br /> • 26 February 2009 Response to December 30, 2008 Technical Comment Letter(Letter) <br /> • . 24 April 2009 Remedial Investigation Work Plan (Work Plan) <br /> Stantec Consulting Corporation (Stantec) submitted these reports on behalf of Pacific Gas & <br /> Electric Company (PG&E) for the general construction yard at 401 East French Camp Road in <br /> French Camp (Site). <br /> PG&E has used the Site since the late 1950s as a general construction yard and purchased <br /> the property in 1991. In June 2005, PG&E performed a Phase I environmental site <br /> assessment, which found that in 1995, PG&E removed one concrete ConVault-style <br /> aboveground tank (AGT). The ConVault tank had replaced older steel AGTs and consisted of <br /> separate vessels for storing diesel and gasoline. The French Camp Fire Department oversaw <br /> the 1995 removal of the ConVault AGT. It is unknown when the steel AGTs were removed. <br /> PG&E submitted the Letter in response to the Central Valley Water Board staff's <br /> 30 December 2008 letter. The staff letter requested clarification on the use of the onsite <br /> domestic well and information on the depth of grab groundwater samples. The letter also <br /> notified PG&E that the concentrations of petroleum hydrocarbons remaining in soil were above <br /> the gross contamination levels, and the Site could not be closed without.consideration of deed <br /> restrictions. <br /> The Work Plan proposes abandoning the three groundwater monitoring wells, abandoning the <br /> onsite domestic well, advancing up to six direct-push soil borings to.confirm the limits of <br /> excavation, and excavating up to 146 tons of contaminated soil from the Site. PG&E will drill <br /> up to six soil borings around MW-1 prior to excavation to determine the approximate <br /> excavation area and volume. PG&E will excavate up to 146 tons of soil in an area 15 feet by <br /> 15 feet around MW-1 to a depth of 11 feet below ground surface (bgs). Following excavation, <br /> PG&E will collect two confirmation soil samples from the floor of the excavation and two <br /> California Environmental Protection Agency <br /> zZa Recycled Foper <br />