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f ARCADES Ms. Lori Duncan December 3, 2010 ' I permits were issued by the SJCEHD on July 28, 2010 and approved encroachment permits were issued by the SPWD on September 7, 2010 (Attachment A). The field activities were coordinated with the SJCEHD and the SPWD and a SJCEHD inspector was present on the site during the well destruction activities to provide oversight. Monitoring Well Destruction Activities ,I r Utility Clearance. Prior to conducting subsurface work at the site, the well locations i were cleared for underground utilities by Cruz Brothers (a private utility locator)and Underground Services Alert (USA)was notified at least 72 hours before the start of intrusive field activities. Well Destruction. Between October 18 and 21, 2010, Cascade Drilling L.P., of Rancho Cordova, California, under the supervision of ARCADIS staff, destroyed 18 groundwater monitoring wells (as noted above). Prior to destruction, the total depth r ; of each well was measured to confirm that the well casing was free of obstructions. Based on the concentrations of petroleum hydrocarbons detected during the most recent groundwater sampling event, the wells were destroyed using one of two methods described below. Pressure Grouting Groundwater monitoring wells MWA, MW-2, MW-3, MW-6, MW-7, MW-9M, MW-90, MW-10M, MW-1 OD, MWA 1 M, MWA 1 D, MWA 2D, MW-13M and MWA 3D were destroyed by removing the well box and well skirt at each well and pressure grouting neat cement into the well casing from the total depth of the well to ground surface, ensuring a complete seal of the screened interval. Subsequently, a drilling rig equipped with 10-inch diameter hollow stem augers with a 12-inch cutter head was used to over-drill the top 5 feet of each well. Additional grout was added as needed to obtain a column of grout to just below surface grade. Surface grade was completed to match existing conditions at each well.location (as described later in 4 this report). f .In the Work Plan, ARCADIS had proposed destroying well MW-5 by over-drilling to its total depth; however, due to its location in a raised planter box, the SJCEHD agreed that this method was not feasible. Therefore, this well was pressure grouted from the total depth of the well to ground surface. The polyvinyl chloride (PVC)well Fcasing was cut at a depth of approximately 1-foot below the planter box surface and the well was topped off with grout. The PVC casing was located within a steel F G:1AprojectENVSF CA•0449316 DeliverablesNell DesVucdon Repor&4493_Weli Destruction Rpt_6351010950.doc Page: 214