Laserfiche WebLink
California&gional Water Quality Conol Board <br /> �.` <br /> Central Valley Region <br /> O <br /> Karl E. Longley, ScD, PE,Chair <br /> Arnold <br /> Linda S.Adams Fresno Branch Office <br /> Secrela,y for Schwarzenegger <br /> Enriron���ewal 1685 E Street,Fresno,California 93706 Governor <br /> Prronm on (559)445-5116•Fax(559)445-5910 <br /> http:// wat�r� ards_ca.�,ov/centralvalley <br /> titUsi0�V17I <br /> 26 March 2008 MAR 2 7 2008 <br /> ENVJRGX\1f,1ENT HEALTH <br /> PERMIT/SERV!,ES <br /> M. Scott Mansholt <br /> Chevron Environmental Management Company <br /> 6001 Bollinger Canyon Road <br /> Room K2066 <br /> San Ramon, CA 94583-2324 <br /> REVIEW — SCREENING LEVEL RISK ASSESSMENT, 990 BEECHNUT PROPERTY, <br /> TRACY, SAN JOAQUIN COUNTY <br /> Regional Water Board staff has reviewed the referenced report, dated 18 March 2008 for the <br /> Chevron Environmental Management Company (Chevron) former Tidewater Associated Oil <br /> Company (TAOC) 990 Beechnut project site in central Tracy. Geomatrix Consultants, Inc. <br /> (Geomatrix) prepared the report for Chevron. <br /> The 3-acre site was part of the former TAOC Tracy Pump Station and pipeline system that <br /> stored and transported heated crude oil from Kern County oil fields to Richmond area <br /> refineries until the late 1960's. The former Pump Station included the 880 Beechnut property <br /> located adjacent and east of the subject site. Pipelines connecting the former Pump Station to <br /> a petroleum storage facility located at nearby Alden Park (adjacent to the west) reportedly <br /> crossed the north and south portions of the subject site. <br /> Additionally, Regional Water Board staff reviewed 1989 to 2004 soil and groundwater <br /> investigation reports, including a 1996 Refined Risk Evaluation report, completed by <br /> Geomatrix and oilier coy lsulting firms for the subject site as well as for Alden Park. <br /> According to the reports, the extent of total petroleum hydrocarbons (TPH)-affected soil had <br /> been adequately defined onsite; a March 2006 investigation report determined that one <br /> groundwater sample from the north part of the site contained low TPH concentrations at or <br /> below analytical detection limits; samples from the central and south part of the site were non <br /> detect. An offsite investigation (north) conducted for the 880 Beechnut site, downgradient of <br /> the 990 Beechnut site, determined that the extent of TPH-affected groundwater was <br /> adequately defined to the north. <br /> Geomatrix's report noted that a City of Tracy ordinance prohibits use of the shallow <br /> groundwater aquifer for domestic purposes and that the City requires any new developments <br /> utilize City water. In addition, San Joaquin County Department of Public Health Services <br /> ordinances require, at a minimum, a 50-foot sanitary seal at the surface of any public water <br /> supply well. Geomatrix concluded that these sanitary seal requirements (extending below the <br /> California Environmental Protection Agency <br /> Cpl Recycled Paper <br />