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s � <br /> Californial0egional Water Quality Cor*ol Board . <br /> Central Valley Region <br /> ion ' <br /> � <br /> Karl E. Longley, SCD,P.E.,Chair �a� <br /> Linda S. Adams Arnold <br /> Secretaryfor 1685 E Street,Fresno,California 93706 Sehwarzenegger <br /> Environmental Phone(559)445-5116-FAX(559)445-5910 <br /> Protection <br /> http://www.waterboards.ca.gov/centralvalley Governor <br /> TO: Clay Rodgers FROM: C. Dean Hubbard <br /> Senior Engineering Geologist Engineering Geologist <br /> P. G. 57 <br /> SIGNATURE: <br /> Shelton R. Gray <br /> DATE: 25 September 2008 ySenioEngineering Geologist <br /> SIGNATURE. <br /> SUBJECT: CONSIDERATION OF REQUEST FOR NO FURTHER ACTION REQUIRED(7r <br /> DETERMINATION, MOUNTAIN HOUSE DEVELOPMENT SITE#7, BYRON <br /> ROAD, MOUNTAIN HOUSE, SAN JOAQUIN COUNTY <br /> Rationale: Crude oil affected soil and groundwater has been delineated, is of limited extent <br /> within an area of approximately 150 by 200 feet, and is defined vertically by samples that <br /> did not contain detectable concentrations of petroleum hydrocarbons from a depth of 48 <br /> feet. The area of affected soil and groundwater are located beneath the West Byron Road <br /> right-of-way (ROW) easement, the Union Pacific Railroad (UPRR) tracks ROW, and two <br /> active refined petroleum products pipelines. The future site use is anticipated to continue <br /> as a utility corridor. An environmental risk evaluation (ERE) completed in 2006, considered <br /> a construction/trench maintenance worker the most likely potential future exposure. Based <br /> on Screening for Environmental Concerns at Sites with Contaminated Soil and <br /> Groundwater, Interim Final, San Francisco Regional Water Quality Control Board, February <br /> 2005, residual crude oil concentrations remaining at the site are below environmental <br /> screening levels (ESLs) for a construction/trench worker scenario. <br /> Consistent with State Water Resources Control Board (SWRCB) Resolution No. 92-49, <br /> Section IIIA through C, Science Applications International Corporation (SAIC) evaluated <br /> alternative cleanup technologies and found that technologies other than natural attenuation <br /> would be ineffective, infeasible, and costly since the affected area is beneath West Byron <br /> Road, the UPRR, and active petroleum pipelines. <br /> Issues: In 2001, crude oil affected soil and groundwater was discovered in the vicinity of two <br /> historical Old Valley Pipelines that cross the property. The pipelines were utilized by <br /> Chevron predecessors to transport crude oil from Kern County oil fields to refineries in the <br /> San Francisco Bay area. The affected soil impacts consisted primarily of total petroleum <br /> hydrocarbons as crude oil (TPHc) which may contain polynuclear aromatic hydrocarbons <br /> (PAHs) and benzene, toluene, ethylbenzene, and xylenes (BTEX). Soil and groundwater <br /> affected by crude oil have been adequately defined. <br /> Setting: Rural agricultural with some nearby residential properties under development. <br /> California Environmental Protection Agency <br /> �a Recycled Paper <br />