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4 � <br /> Californiaegional Water Quality ContrRoard <br /> Central Valley Region <br /> Karl E.Longley,ScD,P.E.,Chair <br /> Linda S.Adams Arnold <br /> SecSacramento Main Office <br /> Environmental viremryJor 11020 Sun Center Drive#200,Rancho Cordova,Califomia 95670-6114 Schwarzenegger Protection Phone( 91 •FAX(916)4644645 Governor <br /> i http://www.wacerbaterboards.ca.govlcentralvalley _ <br /> i <br /> 6 March 2008 <br /> Ben Hall Meredith Durant <br /> Musco Family Olive Company Kennedy/Jenks Consultants <br /> 17950 Via Nicolo 622 Folsom Street <br /> Tracy, California 95376 San Francisco, California 94107 <br /> REVIEW OF PHASE I GROUNDWATER INVESTIGATION REPORT AND WORK PLAN <br /> FOR PHASE II INVESTIGATION, MUSCO FAMILY OLIVE COMPANY, SAN JOAQUIN <br /> COUNTY <br /> The Regional Water Quality Control Board (Regional Water Board) staff has reviewed the <br /> 14 February 2008 Phase I Groundwater Investigation Report and Work Plan for Phase II <br /> Investigation for the Musco Family Olive Company facility located in Tracy, San Joaquin <br /> County. The report is a culmination of site drilling activities requested in a staff memo dated <br /> 12 December 2006 and subsequent meetings between Musco personnel and Regional Water <br /> Board staff. In accordance.with the Cease and Desist Order No. R5-2007-0139, the report <br /> contains the required information requested, including a Phase II Groundwater Investigation <br /> Work Plan. <br /> Phase I drilling activities included the installation of seven groundwater monitoring wells <br /> constructed at varying depths. Wells MW-23 through MW-25 were installed in the uplands <br /> area of the site. Wells MW-24 and MW-25 were installed offsite, south of Field 95. Well <br /> MW-23 was installed adjacent to Well MW-14, west of the reservoir. Wells MW-6R, MW-9R, <br /> MW-10R, and MW-13R were installed as replacement wells to MW-6, MW-9, MW-10, and <br /> MW-13. Well MW-13R was installed in Field 95, downgradient of well MW-1. Well MW-6R <br /> and MW-9R were installed in what can be considered the mid-fan area and well MW-1 OR was <br /> installed in the distal fan area at the most eastern site boundary adjacent to Interstate 580. <br /> All newly installed wells were screened across first encountered groundwater with the <br /> exception of well MW-23 and MW-25. Well MW-23 was installed with 30 feet of steel <br /> conductor casing to isolate first encountered groundwater above. Well MW-25 was drilled <br /> deep to find the confined, high salinity water at depth. First groundwater in well MW-25 was <br /> encountered at a depth of 135 feet below ground surface, overlain by high plasticity, dry clay <br /> approximately 25 feet thick. The water-bearing unit is approximately 5 feet thick and <br /> groundwater rebounded approximately 60 feet above first encountered groundwater <br /> suggesting confined groundwater similar to well MW-2. <br /> California Environmental Protection Agency <br /> C',Recycled Paper <br />