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USEPA Region 2 provided us with the following update on the status of the Gowanus Canal Superfund cleanup on February 27 (edited slightly for elucidation).

In-Canal Work

Remedial Target Area (RTA) 1 (Top of the canal to 3rd Street)

  • The Potentially Responsible Parties (PRPs) are currently laying down the armor mat layer in the canal. They started this stage of the remediation in early November 2023. Mats are inspected for cracks or defects prior to placement and divers measure the spacing between mats. They have currently laid down approximately 132,455 square feet of mats to date (approximately 75% of the total).
  • We expect mat placement to continue until March 2024, followed by subsequent material. Demobilization will occur sometime in May 2024.
  • After mat placement, grout is used to fill in the spaces between the mats. We have held off on placing grout in the top 275 feet of the canal due to a NAPL (non-aqueous phase liquid, a contaminant) issue and within 50 feet of the Carroll Street bridge until the repairs have been completed.
  • Once grout is placed at the head of the canal, the flushing tunnel will be turned back on.
  • The Trust (Gowanus Canal Environmental Remediation Trust established by the PRPs to perform cleanup work) has been conducting air and noise monitoring throughout. They have also been conducting movement and vibration monitoring.
  • We haven’t had any major issues with dissolved oxygen (DO) since the weather cooled off. Still monitoring as significant weather events can also influence the DO.
  • NAPL sheens and blebs have been spotted near the head of the canal
    • From what we see so far visually, it appears that the NAPL seems to be on the surface and that the cap is intact.
    • We don’t yet have results back from the analytical samples that were taken in the vicinity to determine the source of the NAPL.

RTA2 (3rd Street to 9th Street)

  • We are working on the design for the next section of the canal (RTA2) and the 3rd Street Bridge, 4th Street Turning Basin, and 5th Street Turning Basin (3/4/5 Area). RTA2 will be similar in design to RTA1 as it includes dredging, in-situ stabilization, and capping. 
  • We’re currently working with the Trust on the bulkhead designs for RTA2 and coordinating the remediation for all the various parcels and properties.
  • We do not have any updates on the status of the design for the Carroll Street Bridge repair. Design still being worked on.

Combined Sewer Overflow (CSO) Tanks

  • Installation of the perimeter slurry wall at the Red Hook CSO retention tank site on Nevins Street is ongoing. The work is approximately 40% complete and on schedule to be finished by late June/July 2024. In response to odor complaints, the City is constructing a tent over equipment that removes soil and debris from the slurry used in the perimeter wall and can create odors. The tent structure and fabric are in place, though some additional work is needed on the HVAC system in order for the tent to be fully functional. 
  • Asbestos abatement along with debris removal and disposal has begun at structures slated for demolition at the Owl’s Head tank site. Building demolitions are scheduled to begin later this spring.

Upland Sites

  • No new updates

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