Laserfiche WebLink
Californike Tonal Water QualityCogrol Board ° <br /> Central Valley Region y :t <br /> Karl E. Langley,SeD,PE,Chair <br /> Linda S. Adams Arnold <br /> Secretaryfor Fresno Branch Office <br /> 1685 E Street, Fresno,California 93706 Schwovenio g er <br /> F,nvrronrnenta! _ <br /> X59 445-5116•Fax 559 445-5910 Governor <br /> Prosection � ) � ) <br /> liitp://www.walerboards.ca.gov/centraIvaIley <br /> TO: Shelton R. Gray FROM: C. Dean Hubbard <br /> Senior Engineering Geologist Engine'7&g Geologist <br /> DATE: 19 June 2008 SIGNATURE: <br /> i <br /> SUBJECT: ENVIRONMENTAL RISK EVALUATION - MOUNTAIN HOUSE DEVELOPMENT <br /> SITE #4, MOUNTAIN HOUSE, SAN JOAQUIN COUNTY <br /> I have reviewed the referenced report, dated 13 May 2008 submitted by Science Applications <br /> International Corporation (SAIC) on behalf of Chevron Environmental Management Company <br /> (Chevron). The report provides information describing results of an Environmental Risk <br /> Evaluation report summarizing site conditions. The report includes an evaluation of historical <br /> crude oil leaks from the Old Valley Pipeline (OVP) and Tidewater Associated Oil Company <br /> (TAOC) pipelines operated by Chevron predecessors. <br /> Mountain House Development Site #4 (Site #4) is generally defined as an approximately <br /> 150-foot by 250-foot parcel primarily beneath West Byron Road (Byron Road), the former OVP <br /> pipeline right-of-way (ROW) adjacent and parallel to the west side of Byron Road. The Union <br /> Pacific Railroad (UPRR) ROW easement, which includes the former TAOC pipelines and two <br /> active refined petroleum product pipelines, Kinder Morgan and the Bay Area Products Line <br /> (BAPL), are on the east side of Byron Road. <br /> I also reviewed SAIC and Condor Earth Technologies soil and groundwater reports completed <br /> for Chevron between 2001 and 2006. SAIC's 2006 characterization report addressed Site #4 <br /> conditions as a follow-up to a 2001 Condor Earth Technologies soil and groundwater <br /> investigation. <br /> The following summarizes the findings of the soil and groundwater investigations completed at <br /> Site #4. My comments are based on the results and conclusions from the reports. The <br /> purpose of this memorandum is to summarize details of the soil and groundwater analytical <br /> results and investigative findings by the consultants and provide recommendations as part of <br /> an evaluation leading to a determination of No Further Action for Site #4. <br /> Soil <br /> Two Condor soil borings on Site #4 reported total petroleum hydrocarbons as crude oil (TPHc) <br /> at concentrations of 13,000 and 3,600 milligrams per kilogram (mg/kg) at 13.5 and 15 feet, <br /> respectively. SAIC's 2006 follow-up investigation reported TPHc concentrations in two <br /> borings, ranging from 34 to 19,000 mg/kg at depths from one to 16 feet. Benzene, toluene, <br /> ethylbenzene, and xylenes (BTEX) concentrations were non-detect (ND) except for 0.16 <br /> California Environmental Protection Agency <br /> Qa Recycled Paper <br />