Compacting clean fill under tent at Position 1

National Grid’s Remediation Contractor continued with site remediation activities, which included the delivery of construction materials, imported backfill material (stone and common fill), and construction equipment and supplies.   Excavation of impacted materials was completed in Shallow Excavation Area inside the temporary fabric enclosure at Tent Position # 1 in the southeast corner of the site. Load-out and off-site transport of impacted material to approved and permitted disposal facilities was completed at Tent Position # 1.  Imported backfill material placement continued inside Tent Position # 1. Record of construction surveys and construction stake-out surveys continued as site remediation activities progress. Vapor Management System (VMS) operation continued at Tent Position # 1 and worker health and safety monitoring activities continued at the site, as necessary. Test pit explorations were performed on Friday 19, 2009 in accordance with the NYSDEC approved “Expanded Shallow Excavation Area Footprint Study” Work Plan, dated April 2009.

Personnel and equipment decontamination pads were utilized throughout site operations.  Further delineation of work zones (i.e., exclusion, decontamination, and support) continued, as required. Maintenance of the on-site gravel access roads, parking areas and material staging areas, the imported backfill material (i.e., clean fill) stockpile covers, and the perimeter privacy screen continued.    Maintenance of engineering controls and soil erosion and sediment control (SESC) measures continued. Odor and dust suppression activities were conducted, as necessary. National Grid’s consulting engineer continued to monitor the site activities with the fixed base community air monitoring program (CAMP) equipment.

CAMP data is reviewed and compared to specific NYSDEC/NYSDOH approved criteria, known as “Action Limits.” As a result of this evaluation process, site conditions are categorized into two categories, “Operational Condition” and “Action Condition.” The “Operational Condition” is applicable when the data is below the “Action Limits”, and means that normal operations can continue. The “Action Condition” occurs when one or more of the fifteen minute average measurements for Dust (PM10), Total Volatile Organic Compounds (TVOC), Naphthalene or Odor Intensity are greater than the background or upwind measurement by the specified “Action Limits.” Reaching an Action Level requires corrective action or stopping work until the condition is addressed or abates. During the period from June 15, 2009 through June 21, 2009, six fixed base CAMP units and one portable CAMP unit were in-use and measured TVOC and PM10. Fifteen-minute averages for TVOC and PM10 data remained in the Operational Condition. No elevated TVOC and PM10 measurements were reported for the weekly CAMP monitoring period. Weekly Reports of the CAMP data can be found as a separate tab in the Weekly Report Archive section.

For the week of June 22, 2009 through June 26, 2009, Shallow Excavation Area “imported backfill material placement and compaction” remedial activities are scheduled for completion at Tent Position #1.  After backfill operations are completed, the Tent Position # 1 VMS and the tent structural supports will be prepared and relocated west to the proposed Tent Position # 2. After the temporary fabric enclosure is relocated to Tent Position # 2, the tent structural supports will be reinstalled and the VMS will be restarted. Delivery of imported clean backfill material (stone and common fill) will continue. The on-site tunnel entrance closure efforts (i.e., placement of sequential backfill material) are also scheduled. Work zone delineation and maintenance of the on-site gravel access roads, truck lining and tarping stations, personal and equipment decontamination pads, and the truck scale will continue. National Grid’s consulting engineer will continue to monitor the site activities with noise and vibration monitoring equipment, as necessary. Maintenance of engineering controls and SESC measures will continue, as necessary.  Work zone air monitoring, VMS system inspection, and performance monitoring will continue.  Odor and dust suppression activities will be conducted, as necessary. National Grid’s consulting engineer will continue to monitor the site activities with CAMP equipment.