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Woodward-Clyde <br /> Consultants <br /> Mr. James L. Tjosvold <br /> California - Environmental Protection Agency <br /> July 28, 1995 <br /> Page 3 <br /> decommission MW-6, MW-14, MW-14D, and MW-30 located on Nelson Ready-Mix <br /> Company property adjacent to the 2041 Navy Drive site. <br /> FIELD ACTIVITIES <br /> On June 5, 6, and 22, 1995, Woodward-Clyde observed the decommissioning of the 17 <br /> monitoring wells at the two former Lika facilities in Stockton, California (Figure 1). Five <br /> monitoring wells (MW-1 through MW-5) were decommissioned at the 1856 Field Avenue <br /> site (Figure 2), and twelve monitoring wells (MW-1, MW-2, MW-3, MW-4, MW-5, MW- <br /> 6) MW-14, MW-14D, MW-15, MW-16, MW-16D, and MW-30) were decommissioned at <br /> the 2041 Navy Drive site (Figure 3). Table 1 summarizes the specifications of the 17 <br /> monitoring wells. The well decommissioning activities were conducted by Spectrum <br /> Exploration of Stockton, California. The groundwater monitoring well decommission <br /> (abandonment) activities were inspected by Ms. Diane Hinson, Supervisor-Site Mitigation <br /> Unit, SJCEHD. <br /> The field activities described below were conducted in accordance with "Appropriate <br /> Techniques to Decommission (Abandon) Wells and Boreholes", Department of Toxic <br /> Substance Control-Region 1, California Environmental Protection Agency; "Water Well <br /> Standards: State of California", Department of Water Resources; and information provided <br /> by SJCEHD. <br /> Each monitoring well was checked to assess if the well casing was free of obstructions <br /> (sediment or debris). This was conducted by lowering a "well sounder" into the well casing <br /> to measure the depth to groundwater and total depth of the well. The average depth to <br /> groundwater at the Field Avenue site was measured at 5 feet below ground surface (bgs). <br /> The average depth to groundwater at the Navy Drive site was measured at 13 feet bgs. <br /> Each groundwater monitoring well was decommissioned by "pressure grouting" methods <br /> except for MW-1 and MW-3 at the Field Avenue site, and MW-6, MW-16, and MW-16D <br /> at the Navy Drive site. These wells were abandoned by placing a continuous pour of neat <br /> cement to surface levels. All of the surface completion christy box well enclosures were <br /> removed except for MW-3 at the Field Avenue site. The well abandonment techniques were <br /> approved by Ms. Hinson (SJCEHD). <br /> 90189N/LUCA.REP(07-28-95)SAC <br />