SITE HISTORY - Laserfiche WebLink

Home Browse Search

i 3.0 DESTRUCTION OF GROUNDWATER MONITORING WELLS 'j The objective of this scope of work was to remove the three groundwater monitoring wells and any generated waste, so that the regulatory agencies could close thecase and issue a "No Further Action Required tetter. To achieve this objective, RamaI a Environmental supervisedervised it the destruction of the monitoring wells and coordinated the proper disposal of waste well 4 materials and soil from the site. 3.1 Planning and Permitting j On October 24, 2008, San Joaquin County EHD issued permit(SR#55761) to destroy the three monitoring wells. Since all three monitoring wells were located on the subject site, neither private property access agreements nor encroachment permits were il required. A copy of the approved well destruction permit is included in Appendix A. I At least two working days prior to field work, Ramage Environmental notified EHD and r �Underground Service Alert so that regulatory and underground I!utility inspections could be a scheduled (USA Ticket#568319). 3.2 Monitoring Well Destruction and Site Restoration j On November 8, 2008, under Ramage Environmental supervision and EHD inspection, All Well Abandonment (AWA), a state of California licensed drilling contractor (C-57 License#848359) destroyed the three wells. Prior to destroying the wells, AWA measured the depths to groundwater and total depths of the wells. The total depths of the wells ranged from 25.0 feet in MW-1 and MW-2 to 35.0 feet in MW-3. The depth-to-groundwater ranged from 12.8 feet bgs in MW=,1 to 26.0 feet bgs in MW 3. . 13 All three monitoring wells were originally constructed as 2-inch diameter wells in 8-inch diameter boreholes. Monitoring wells MW-1 and MW-2 were installed to depths of 25 feet, and MW-3 was installed to 35 feet bgs. All three wells were constructed with 20 feet of polyvinyl chloride l (pvc) well screens, and blank pvc casings. The monitoring well logs',are included in Appendix E. AWA destroyed all three wells by over-drilling the boreholes a`d casings with a CME-75 truck- mounted drilling rig and 8-inch diameter hollow-stem augers. AWA removed the street boxes and all well casing materials, drilled out the annular seals and falter packs, and filled the boreholes with neat cement grout, placed to the bottoms of the boreholes with a tremie pipe. r I 1 10 1 3 e