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Scope of Work <br /> 2.0 2000-foot Radius Well Survey and Sensitive Receptor Survey <br /> Wright will perform a 2000-foot radius search for wells around the Delta site. The search will <br /> use the available information from the Department of Water Resources files and City of Tracy <br /> and County files to document municipal, domestic, agricultural, industrial and other wells. The <br /> information will be compiled into a summary table together with a map showing the well <br /> locations. Additional information will include a brief review of potential sensitive receptors in <br /> the area. <br /> 3.0 Field Methods—Drilling and Sampling Exploratory Borings <br /> Three (3) exploratory borings will be drilled at the locations shown on Figure 1. Drilling and <br /> well installation permits will be secured from the SJC/EHD, and an underground utility clearance <br /> will be performed prior to doing the fieldwork. A site safety plan and traffic control plan will be <br /> prepared for the site work. The wells will be installed on the north and south side of 6' Street. <br /> The wells will be advanced to depths of about 20 to 25 feet but not below the aquitard. <br /> The boreholes will be drilled with a truck-mounted hollow-stem auger rig. All drilling <br /> equipment and sampling tools will be cleaned prior to arriving, and before leaving the site. The <br /> decontamination process will use a tri-phosphate soap to wash the soil sampler between each <br /> sample run and each borehole. Augers and drill rods will be decontaminated in similar fashion <br /> between each borehole using a pressure washer to clean and remove soil/sediment adhering to <br /> the augers, rods and drill bits. The hollow-stem augers will be advanced and discrete soil samples <br /> will be collected at five-foot intervals of depth from each borehole. The augers and drill rod will <br /> be advanced to the desired sampling depth interval, and a drive split spoon sampler was driven <br /> ahead of the drill bit. The soil samples will be sealed with Teflon paper and plastic endcaps, <br /> labeled, logged onto chain-of-custody forms and place in a chilled ice chest on crushed ice for <br /> transport to a State certified analytical laboratory. <br /> The boreholes will be logged using the Unified Soil Classification System under the supervision <br /> of a professional geologist. Additional lithologic information will be collected to describe the <br /> subsurface geology. The soil samples will be collected at five-foot intervals, at intervals of <br /> obvious contamination and at stratigraphic features of interest. Soil samples will be field <br /> screened with a portable photoionization detector(PID) for fuel hydrocarbons vapor and staining. <br /> Samples showing elevated PID readings will be selected for chemical analysis. If field screening <br /> is inconclusive, soil samples will be selected based upon possible staining, site stratigraphy and <br /> near the occurrence of groundwater. Upon completion of the borehole drilling and collection of <br /> soil samples, three (3) boreholes will be converted to groundwater monitoring wells using the <br /> procedures discussed below. <br /> Page 2 of 5 <br />