The Gowanus Canal cleanup: What to expect

Gowanus canal
Barge-mounted excavators just south of the Carroll Street Bridge.
Photo by Kevin Duggan

The federally-supervised cleanup of the Gowanus Canal kicked into high gear this week as the Environmental Protection Agency launched their full-scale dredging of the upper portion of the toxic waterway on Monday.

The agency has tasked more than 30 historic polluters of the Gowanus, including National Grid and the City of New York, with the more than $1.5 billion cleanup effort, which will cleanse the 1.8-mile canal in three phases, starting with the stretch north of the Third Street Bridge that will wrap up in mid-2023 and cost $125 million.

Barge-mounted excavators will scoop out 72,400 cubic yards of the putrid, poisonous sediment at the bottom of the canal known locally as “black mayonnaise” — a volume of gunk that could fill roughly 22 Olympic size swimming pools!

Dredging will start just south of the Carroll Street Bridge, before continuing up to the Union Street Bridge, and then further south to the Third Street Bridge.

Barges small enough to navigate the narrow canal will bring the piles of filth to a staging site at Huntington and Smith streets, where they will drain out excess water, before transferring it to larger barges for shipping out of the Gowanus and across New York Harbor to New Jersey to be processed.

Once in the Garden State, the slimy sludge will be screened for larger materials like tires and wood, before being recycled for new uses such as landfill cover, according to the EPA.

After dredging the gunk from the waterway, contractors will inject the canal bed with cement to solidify and stabilize the native sediment, before installing a multi-layer cap to catch remaining contaminants from percolating back into the water.

The EPA also plans to restore the First Street Turning Basin, a defunct and filled-in offshoot of the canal that the agency wants to revitalize as a wetland area.

During the work, there will be frequent openings of the Union Street, Carroll Street, Third Street, and Ninth Street bridges to allow the barges through, and parties involved will coordinate traffic with the city’s Department of Transportation.

Huntington Street east of Smith Street will be closed through September 2021, and additional closures are possible depending on the work progress, according to EPA. There will also be restrictions on recreational boating and canoeing north of the Ninth Street Bridge.

Monitors will regularly survey air quality, noise, vibration, movement, and water quality during the cleanup, and readings will be posted online at www.gowanussuperfund.com.

EPA has established a community hotline that you can call 24-7, and during work hours complaints and concerns will be relayed to an on-site supervisor and EPA (718) 403–2451.

For more information about the site, EPA has published factsheet on phase one of the cleanup. You can also contact EPA’s community involvement coordinator Natalie Loney at (212) 637–3639 or loney.natalie@epa.gov.