Cap Construction

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 relocation activities from Tent Position #12 to the next Tent Position (Tent Position #11) were completed. Tent relocation activities included 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 were reset as the final phase of the tent position relocation. Tent Position #11 Shallow Excavation activities commenced with off-site transport and disposal of impacted soils at approved and permitted disposal facilities. Backfill material placement and compaction was also commenced inside the Tent Position #11 Shallow Excavation. Common fill material deliveries and final grading and cap installation activities were completed in the western part of the site and continued to progress toward the central 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.

Waterloo Barrier Installations

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 April 12, 2010 through April 18, 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 19, 2010 through April 23, 2010, Tent Position #11 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 to continue inside Tent Position #11.  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 scheduled to continue  to progress toward the central 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.