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Work Plan for Limited Site Investigation <br />Proposed Distribution Center Stockton, California <br />February 22, 2022 Terracon Project No. NA227001 <br />Responsive Resourceful Reliable 3 <br />2.5 Utility Location and Geophysical Survey <br />Following SJCDEH approval of this Work Plan, and no later than 72 hours prior to intrusive <br />activities, Terracon will contact Underground Service Alert (USA) 811 North to arrange for <br />underground utility locates at the site. <br />To further evaluate the underground utilities at the site, a geophysical survey will be performed in <br />the vicinity of each of the proposed sample locations where mechanical drilling will be performed. <br />Terracon will utilize ground-penetrating radar (GPR) to detect any concealed utilities at each select <br />sampling location. GPR activities will be completed on the first day of planned drilling activities. <br />2.6 Sampling and Laboratory Analytical Program <br />A total of six 70-foot temporary sampling wells (TSWs) and six 15-foot soil borings will be advanced <br />at the site. A description of the sampling points, construction and sampling is presented below. <br />Refer to the attached Site Diagram (Exhibit 1) for the proposed boring locations. <br />The proposed sampling locations may be modified in the field to account for access limitations <br />and/or site conditions. The client will be notified of any significant modifications to the sampling <br />locations. The sampling and analytical program are summarized in the attached Sampling and <br />Analytical Plan. Details on sample collection and handling procedures are provided below. <br /> Soil Borings <br />No later than 48 hours to the start of field work, Terracon will notify SJCDEH of our proposed work <br />day and confirm that a representative of the SJCDEH will be available for a backfilling inspection. <br />Drilling services for the proposed soil borings will be performed by a State-of-California C-57 <br />licensed driller using a track, or truck-mounted hollow-stem auger drill rig under the supervision of <br />a Terracon environmental professional and the oversight of a Terracon licensed Professional <br />Geologist (P.G.). <br />Six soil borings will be advanced on the site using a hollow-stem auger drill rig to depths of <br />approximately 70-feet bgs, five feet into the first encounter of groundwater, or refusal, whichever <br />is encountered first. Additionally, six 15-foot soil borings will be advanced using a hollow-stem <br />auger drill rig. <br />During drilling activities, soil samples will be continuously collected to document lithology, color, <br />and relative moisture content. In addition, the soil samples will be field screened using sensory <br />methods and an organic vapor meter (OVM) equipped with a photoionization detector (PID) to <br />detect the presence of organic vapors.