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Mr. James L. L. Barton HOLGUIlV FAHAN California Regional Water Quality Control Board Central Valley Region &ASSOCIATES, INC. September 30, 2009- Page 2 ENVIRONMENTAL MANAGEMENT CONSULTANTS Attachment 2 for the well destruction permits). Monitoring wells MW-6, MW-7, MW-9, MW-12, MW-13, and MW-14 were destroyed by removing the well vault and overdrilling with 10-inch-outside-diameter; hollow-stem augers to 2 feet below the total depth of each well to remove the casing, filter pack, annular seal and all associated well materials. All boreholes were then grouted from the bottom of the borehole to surface grade. Monitoring wells MW-4, MW-8, and MW-10 were abandoned via pressure grouting due to their close proximity to underground utility lines. Monitoring well MW-11D- was also abandoned via pressure grouting due to the presence of conductor casing. The pressure grouting was performed utilizing the procedure outlined in the work plan addendum dated August 12, 2009, and under the supervision of Mr. lnfurna (HFA, 2009a). Three unknown surface installations were discovered during abandonment activities that had not been documented in previous reports. Each installation consisted of PVC casing set inside of 8-inch, traffic-rated steel vaults. In two of the installations the PVC casing appeared to be filled with Portland cement grout. The third installation appeared to be filled with gravel. After discovery, the vault lid was removed from each location and the vault was filled with cement to surface grade as directed by Mr. Infurna. Following the removal of wells MW-13 and MW-14, the surrounding sidewalk was repaired to the specifications outlined in the encroachment permit. The procedure included replacing the concrete from score mark to score mark. The repair of the sidewalk adjacent to MW-12 will occur pending contractor availability. . Monitoring wells MW-2, MW-3, and MW-5 were transferred to the Lincoln Center Environmental Trust for use.in their open environmental case. Gettler-Ryan performed repairs on these wells on September 28, 2009. These repairs included the drilling and tapping of new tabs, the installation of new bolts, and the installation of a new well vault gasket for each well. Additionally, a new well vault lid was installed on MW-5 and additional grout was added inside the well vault to raise the level of grout within the well vault. Well materials and soil removed from.each borehole were stored on-site in 55-gallon Department of Transportation-approved drums pending disposal and were subsequently,removed from the site on August 31, 2009 (see Attachment 3 for the waste manifest).