Moving the tent westward from Position 1 to Position 2

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.   Tent Position #1 Shallow Excavation Area imported backfill material placement and compaction remedial activities were completed.  Vapor Management System (VMS) operation continued at Tent Position # 1 and worker health and safety monitoring activities continued at the site, as necessary. After the completion of the backfill operations, the Tent Position # 1 VMS, the temporary fabric enclosure (tent) and the tent anchoring system were disassembled and relocated west to the proposed Tent Position # 2. After the tent was relocated to Tent Position # 2, the tent anchoring system was reassembled and the VMS re-installed.  In addition, the on-site tunnel entrance closure efforts (i.e., placement of sequential backfill material) was completed.  Record of construction surveys and construction stake-out surveys continued as site remediation activities progress.

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.

Continued compacting of backfill in Position 1

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 22, 2009 through June 28, 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. During the evening hours of Friday, June 26, 2009 between 1722 Hours (5:22 PM) and 1813 Hours (6:13 PM), elevated concentrations of PM-10 particulates were reported at the fixed base CAMP unit FAM-6. These elevated concentrations for a period of 50 minutes were caused by high moisture (high humidity and rain) conditions and were not associated with site intrusive activities. These weather related elevated concentrations diminished when the rain ended. These weather related conditions interfered with the true measurement of PM-10 at the site and background concentrations reduced all elevated concentrations below the action limit; therefore the site remained in the Operational Condition (less than the Action Limit). Weekly Reports of the CAMP data can be found as a separate tab in the Weekly Report Archive section.

For the week of June 29, 2009 through July 2, 2009, Shallow Excavation Area remedial activities are scheduled to commence at Tent Position #2 with off-site transport and disposal of impacted soils at the approved and permitted disposal facilities. Delivery of imported clean backfill material (stone and common fill) will continue. 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 and 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.