Contractors working on the installation of the 12-inch water main extension in Long Island Avenue

Sevenson Environmental, National Grid’s Remediation Contractor, completed excavation within the fourth temporary fabric structure (TFS) location on Friday, March 20. Sevenson’s survey contractor, Nelson & Pope, completed the confirmation survey of the final excavation depths and backfilling of the excavation was completed. The ancillary equipment was removed from the TFS in preparation of the move to the fifth excavation location. 3,327.26 tons of MGP-impacted soils were removed and transported from the site to a thermal treatment facility in Southeast Pennsylvania. A total of 4,417.98 tons of soil were removed from the fourth TFS location and the total amount of soil removed from the site to date is 25,735.79 tons.

Sevenson’s dewatering subcontractor, Griffin, continued operation the excavation dewatering system until backfilling operations were completed. The dewatering system was temporarily shut down on Friday and headers disconnected from the dewatering wellpoints. During the shutdown, water treatment plant personnel conducted maintenance operations on the plant including backwashing of the sand and carbon vessels. 1,800,289 gallons of water was treated this week, bringing the total amount of treated water discharged from the site to 12,208,389 gallons.

Worker directing a dump truck into the temporary fabric structure (TFS) to receive its load of MGP-impacted soil

Two-Week Outlook

The fourth move of the TFS is scheduled for early next week, followed by reconnection of the air handling and carbon filtration units and other ancillary equipment.  Excavation activities at the fifth TFS location are anticipated to begin mid-week and continue into the following week.  Access road re-alignment for on-site truck traffic, site grading, and site maintenance activities will continue in preparation for excavation of the fifth location. Backfill material will continue to be delivered to the site on an as-needed basis.

Sevenson’s dewatering subcontractor will connect the headers to the wellpoints installed at TFS positions 4 and 5 and remove the wellpoints installed at the third TFS location.  Dewatering will begin prior to the commencement of excavation activities at the fifth excavation location.  Groundwater removed from the excavation footprint will be pumped to the water treatment plant and discharged.

Roadwork Construction Corporation, a Sevenson subcontractor, completed the installation of approximately 75 feet of 12-inch water main from Bridge Street east along Long Island Avenue to the existing 12-inch water main this past week.  Roadwork will progress west towards Main Street to begin to tie-in the businesses located along Long Island Avenue to the new 12-inch water main.  Water main work along Long Island Avenue will continue to be conducted during the general site operation hours, with work scheduled to be completed by Friday, April 3.  Again, one lane of Long Island Avenue from Main Street to Bridge Street will be closed with traffic controls in place to support 2-way traffic flow on Long Island Avenue.

Utility crews continue to work on the temporary re-location of overhead lines on northern Bridge Street to Long Island Avenue in preparation for the excavation of soils beneath Bridge Street.  The line re-location is anticipated to be completed within the next two weeks.

General hours of operation will continue to be Monday through Friday, 7:00 AM to 5:00 PM, and Saturdays, between 8:00 AM and 6:00 PM.