The productive industrial history of the Gowanus neighborhood left behind a legacy of industrial contamination in the Canal and on its banks. Today, there are two major forms of pollution in the Gowanus Canal: historic industrial pollution from former industrial and manufacturing activities lining the Canal and ongoing Combined Sewer Overflow (CSO) from the three square mile sewershed. The primary legacy contaminant of concern is coal tar, a by-product from manufactured gas plants, but there are numerous other contaminants in the soil and sediment. 

In 2010, the Gowanus Canal was designated a Federal Superfund site by the U.S. Environmental Protection Agency (EPA). This spurred a $500 million clean-up process to dredge an average of 10 feet of contaminated sediment from the bottom of the canal, and cap the native sediment below. 

Shortly after Superfund designation, the Gowanus Canal Community Advisory Group (CAG) was formed and remains the largest U.S. Environmental Protection Agency (EPA) Superfund Community Advisory Group in the nation. The CAG is made up of over 50 representatives from civic, environmental, business, and community organizations, including Gowanus Canal Conservancy, as well as individual members, from around the Gowanus Canal such as Red Hook, Gowanus, Carroll Gardens, Boerum Hill, and Park Slope. The Gowanus Canal CAG meetings are held monthly and open to the public. For regular updates or to become a CAG member, visit the Gowanus Canal Community Advisory Group (CAG) website

Superfund Updates: 

In January of 2020, the U.S. EPA issued an Executive Order requiring the start of the Gowanus Canal Superfund site cleanup. The order involves full-scale dredging and capping of the upper Canal, denominated as Remediation Target Area (RTA) 1, as well as restoration of the 1st Street turning basin. RTA 1 is the first of three areas of the Canal that are targeted for cleanup and the restoration of the contaminated filled-in former 1st Street turning basin will serve as the primary wetlands area for mitigating encroachment by the construction of bulkheads along the Canal.

As of October 6, 2021, The Environmental Protection Agency has completed its initial phase of dredging north of the 3rd St. Bridge (RTA1) and 35,000 cubic yards of contaminated sediment has been removed. Most of this sediment has been processed to be used as landfill cover. 

The In-Situ Stabilization (ISS) process for RTA1 will begin in mid-October, starting with a demonstration phase to identify the process and materials necessary. ISS is a remediation technique where native sediments are injected with chemical compounds in order to stabilize contaminants of major concern in place, so that they are unable to spread any further through the Canal. In segments of the middle and upper Canal where there are pockets of especially contaminated sediment, this process will be employed. 

Stabilization and capping of the first segment of the Canal will continue through early 2024. Frequent bridge and street closures will be required as bridges are studied and repaired to ensure full structural support during the ongoing dredging process. 

In October of 2018, the 4th Street Basin pilot study was completed to provide information necessary to complete the full-scale dredging and capping for the upper Canal, from Butler Street to 3rd Street. Results from the pilot were used to evaluate and finalize the design elements for the full Canal dredging and capping portion of the remediation, including:

  • Selection of equipment and optimizing logistics to conduct the work within the tight constraints of the Canal
  • Optimizing the processing and disposal of the dredged material
  • Optimizing methods for installing the multi-layered cap

According to former EPA Remedial Project Manager, Christos Tsiamis, this was the first time in 150 years that a portion of the Canal has a clean bottom.

For more information about what’s going on in the Canal right now and over the coming months, see recent presentations from the EPA. 

Learn more:

Gowanus Canal Community Advisory Group (CAG)

EPA Gowanus Canal Superfund Site

Cleanup of the Gowanus Canal