More than a dozen contaminants, including heavy metals like mercury, lead and copper, were found in the canal’s sediment, making it one of the most highly contaminated bodies of water in the country.
Last year, the EPA divided the Gowanus Canal cleanup into three sections. The upper portion, which runs from the top of the canal to the 3rd Street Bridge, contains an intermediate level of contamination.
The middle portion, which runs from the 3rd Street Bridge to south of the Hamilton Avenue Bridge, contains the most heavily-contaminated sediment.
Meanwhile, the lower portion, which runs from the Hamilton Avenue Bridge to the mouth of the canal, has the least amount of contaminated sediment.
The current pilot project will lead the engineering design to dredge and cap the entire Gowanus Canal.
Nearly 17,000 cubic yards of contaminated sediment has already been dredged from the Gowanus Canal’s 4th Street Turning Basin, while work is currently being done to cap the bottom.
To create a cleaner canal, layers of sand, clay and carbon-absorbing material will be placed on the bottom of the basin.
On Monday, EPA Regional Administrator Pete Lopez visited the site to see the pilot project enter its final stages. The pilot study is expected to last until fall, while the site’s entire cleanup will take about five years to complete.
“The whole initiative is to dredge 600,000 cubic yards of sediment, have bank stabilization and finish with capping,” Lopez said. “This initiative was really reflective of a broader nationwide conversation, which protects public health and the environment.”
During the project, steel sheet plates were installed along the sides of the canal to allow for the dredging. Sediment was removed and taken off-site for treatment and disposal.
There was also focus on implementing controls to prevent combined sewer overflows from compromising the cleanup.
While working on the project, crews encountered some issues. Soft materials along the bank on the 4th Street Turning Basin, located directly near Whole Foods, moved substantially as the dredging began.
Vibrations from the project further worsened the situation. Part of the pedestrian pathway has started to slope somewhat as a result.
Though officials said the main structure is solid, part of the pedestrian area near the Whole Foods has been closed for security reasons.
Lopez said that one of the goals of the pilot project is to help the engineers realize what method work best to stabilize the banks.
Lopez added that the EPA has an agreement with Whole Foods to help restore the property back to its previous condition.
“This is like a working laboratory, so we’re going to hit the brakes and learn how to work with the issues and apply it to the rest of the canal,” Lopez said. “The soft materials will be removed and will be replaced with compact materials and stones, and the pedestrian amenities will return.
“We keep a close eye because we don’t want anyone to be hurt,” he further said.
Assemblywoman Jo Anne Simon said the cleanup project was an example of how well the community can work together on complicated issues, starting from a federal level down to the local level with input from community groups and the business community.
“The number of people who can now call themselves climate scientists has increased dramatically because of all our work on the Gowanus Canal,” Simon said. “We learn from each other and we want to celebrate the history of the canal.”