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1 <br /> URS <br /> Ms. Natalia Subbotnikova <br /> San Joaquin County Environmental Health Department ' <br /> November 10, 2011 Page 2 of 4 <br /> Based on 4Q06 monitoring results, RWQCB sent a letter to Tandy Corporation dated ' <br /> February 20,2007, which identified eight constituents(TDS, aluminum, arsenic, barium, iron, lead, <br /> manganese,and nickel)that exceeded water quality goals, and requested Tandy Corporation to <br /> investigate the extent of groundwater impacts. In a May 24, 2007, meeting, Mr. Atkinson concurred ' <br /> with the recommendation in the Quarterly Monitoring Report dated April 30, 2007,to suspend the <br /> groundwater monitoring activities for VOCs,and also agreed that additional groundwater monitoring <br /> results were needed before completing additional groundwater investigation activities. ' <br /> In a meeting on November 1, 2007,Mr. Atkinson specified that the following two items were needed <br /> before RWQCB could decide whether to conduct further investigation,continue groundwater <br /> monitoring activities, or to close the site: (1)information as to whether a local water service company , <br /> provides water to residents in the area near the site, and(2)the results of a well search following <br /> receipt of RWQCB's authorization to complete the well search. URS provided the findings of these <br /> two items in a letter to RWCQB dated May 20,2011. URS recommended no further action for , <br /> groundwater activities. RWQCB agreed that on-site groundwater issues had been resolved to their <br /> satisfaction(Attachment A). <br /> SCOPE OF WORK ' <br /> URS will provide oversight to Precision Sampling of Stockton, California, during decommissioning of <br /> the monitoring wells to verify that the work is conducted in accordance with all applicable state and ' <br /> local regulations. <br /> Permitting ' <br /> URS will submit a drilling permit application to SJCEHD before work will begin. Once the approved <br /> permit is received,URS will schedule the work. t <br /> Utility Clearance <br /> URS will mark the excavation areas in white paint and notify Underground Service Alert(USA)a ' <br /> minimum of 48 hours prior to commencement of field activities. <br /> Well Decommissioning Methods <br /> Well construction logs indicate the monitoring wells were constructed of 2-inch-diameter polyvinyl ' <br /> chloride and were screened at various intervals between 10 and 29 feet below ground surface(bgs) <br /> (Table 1,Attachment B). <br /> The flush-mounted well cover and concrete pad will be removed. As discussed with you on ' <br /> November 4,2011, each well will be pressure-grouted from total depth to near surface and capped <br /> with using Portland Type I/II cement with approximately 3%bentonite powder. An approximate ' <br /> 2-foot-diameter area(measured from the well casing)will be excavated to allow for the grout cap. The <br /> approximate bottom of the excavation pit will be approximately 2 feet bgs, but no deeper than 4 feet <br /> 1 <br /> H..\Wprocess\255321WoddEnterprise\Well Destruclion\Repod.doc <br /> 1 <br />