Weekly Update: April 02, 2010

Tent Position 12 Operations

National Grid’s Remediation Contractor continued with site remediation activities, which included the delivery of construction materials, imported backfill material (stone and common fill), as well as construction equipment and supplies. Tent Position #12 Shallow Excavation activities continued with off-site transport and disposal of impacted soils at approved and permitted disposal facilities. Backfill material placement and compaction continued inside the Tent Position #12 Shallow Excavation. Common fill material deliveries and final grading and cap installation activities continued in the western part of the site. Phase 1b On-Site 120-foot deep DNAPL Migration Barrier Wall planning and mobilization activities continued in accordance with the NYSDEC-approved Field Change Request, FCR-06. National Grid’s consulting engineer conducted noise and vibration monitoring activities, as necessary.

Maintenance of the decontamination areas, work zones, on-site gravel access roads, parking areas and material staging areas, imported backfill material (i.e., clean fill) stockpile covers, the perimeter privacy screen, and soil erosion and sediment control (SESC) measures continued. Odor and dust suppression activities were conducted, as necessary. National Grid’s consulting engineers continued to monitor the site activities with the community air monitoring program (CAMP) equipment.

Tent Position #12 Shallow Excavations

During the period from March 29, 2010 through April 4, 2010, six fixed base CAMP units and one portable CAMP unit were in-use and measured total volatile organic compounds (TVOC) and particulates (PM10). Fifteen-minute averages for both TVOC and PM10 data remained in the Operational Condition.  No elevated TVOC or PM10 readings were reported for the weekly monitoring period. The Weekly Report that summarizes the CAMP data can be found as a separate tab in the Weekly Report Archive section.

For the week of April 5, 2010 through April 9, 2010, Tent Position #12 Shallow Excavation activities are scheduled to be completed with off-site transport and disposal of impacted soils at approved and permitted disposal facilities. Delivery of imported clean backfill material (stone and common fill) and backfill material placement and compaction are also scheduled for completion inside Tent Position #12.  Tent relocation activities from Tent Position #13 to the next Tent Position are scheduled to commence. Tent relocation activities will include the temporary disassembly and staging of tent anchors and the vapor management system (VMS), temporary removal of the central panel, end panels and access doors, followed by the relocation of the two tent sections and replacement of the central panel, access doors, and end panels.  The temporary fabric enclosure supports, tent anchors, and VMS will be reset as the final phase of the tent position relocation.   In addition, Phase 1b On-Site 120-foot deep DNAPL Migration Barrier Wall planning activities are scheduled to continue in accordance with the NYSDEC-approved Field Change Request, FCR-06.    Cap material deliveries and final grading and cap installation activities are also scheduled to continue in the western part of the site.  Odor and dust suppression activities will be conducted, as necessary.  Work zone delineation, site maintenance activities, and CAMP operation monitoring activities will continue.