Laserfiche WebLink
7-Eleven/Stockton 6 <br /> November 1989 <br /> In March 1989, GTI submitted a work plan for further site <br /> assessment activities. Additional plans were made to increase <br /> flow rates through the shallow vapor extraction points and to <br /> expand the soil-vent system to allow for deeper influence in <br /> order to provide more aggressive soil remediation. In April <br /> 1989, vacuum tests were conducted on the existing and future <br /> soil-vent extraction wells. The feasibility of using an ORS <br /> Catalytic Scavenger Vapor Abatement System (System) for vapor <br /> treatment was confirmed. <br /> In May, 1989, pumping was discontinued in PW-1 due to the <br /> continued decline of groundwater levels. Groundwater pumping is <br /> currently restricted to RW-1. During this reporting period, <br /> pumping from RW-1 continued at a rate of 0.6-1.0 gallons per <br /> minute (gpm) . <br /> REGIONAL GEOLOGY PSiD HYDROGEOLOGY <br /> The regional geology in the Stockton area consists of two <br /> general stratigraphic units: lower consolidated units and <br /> overlying unconsolidated units. The consolidated rock units are <br /> composed of the Mehrten and the Valley Springs Formations. These <br /> formations are of volcanic origin and contain andesitic and <br /> rhyolitic breccia, tuff and ash. The unconsolidated units <br /> consist of the Victor Formation, Arroyo Seco Gravel and the <br /> Laguna Formation. These formations have a total accumulation of <br /> approximately 1,100 feet and are composed of clay-to-gravel size <br /> materials. Intervals of hardpan occur throughout the <br /> unconsolidated formations. <br /> The lower consolidated formations generally produce saline <br /> water and the overlying unconsolidated formations produce fresh <br /> water. The groundwater within these units is separated by an <br /> (.k(it%])WATI:H <br />