Weekly Update: March 26, 2010

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Cap Placement

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. The Remediation Contractor completed repairs to the site perimeter security fence, security gates, soil erosion controls, and the temporary fabric enclosure in response to damage from the March 12, 2010 and March 13, 2010 storm event. Two-foot perimeter cut activities were completed in the western part of the site. Tent Position #12 Shallow Excavation activities commenced after the temporary fabric enclosure repairs and final assembly (setup central panel, anchor ballast, doors, and VMS) were completed.  Off-site transport and disposal of impacted soils at approved and permitted disposal facilities commenced. Backfill material placement and compaction commenced 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.

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Cap Placement and Replacement of Pole

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.

During the period from March 22, 2010 through March 28, 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 March 29, 2010 through April 2, 2010, Tent Position #12 Shallow Excavation activities are scheduled to continue 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 inside Tent Position #12. In accordance with the NYSDEC-approved RDR, clean soil from the two-foot perimeter cut activities are scheduled for reuse as Tent Position #12 Shallow Excavation backfill material.  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.