Gowanus Canal dredging set to begin in December

The dredging will remove the ten feet of gummy toxins coating the bottom of the canal near the Fourth Street Basin

The days are numbered for the 10 feet of black mayonnaise settled at the bottom of the Gowanus Canal. The Environmental Protection Agency announced this week that it's ready to move forward with the next phase of the pilot study for the $507 million remediation of the toxic waterway.

Come October 5, barges will arrive at the canal's Fourth Street Basin, at the intersection of Fourth Street and Third Avenue, to begin dredging, DNAinfo reports. The action will clear the way for the removal of the canal's floor, allowing for dredging to begin in December.

The dredging work that begins in December is expected to last about two months and will be followed by a capping procedure that will coat the bottom of the canal preventing other toxins from being absorbed. That procedure is expected to wrap in April. The work will inform the EPA's final plan for remediation of the 1.8-mile waterway.

The first phase of the canal's pilot study involved removing large debris, identified via sonar, that obscured access for barges and other clean-up mechanicals. The trash that was removed from the canal includes trees, tires, boulders, tons of rebar, and even the collapsed fiberglass hull of a boat. The debris, as well as some sediment that was removed during this phase, will be processed off site.

Sediment removed from the canal will be mixed with concrete before it is shipped off for processing to ensure it doesn't leach contaminants. Brooklyn Paper notes that some of the removed sediment will be used as cover material in landfills while sediment with too much liquid tar will be sent to facilities that can burn it away.

The EPA anticipates finalizing a plan for the cleanup of the canal's northern portion by February 2019, with plans for the entire cleanup to wrap in 2022.

• Dredging of Gowanus Canal's Toxic Sludge Set To Begin, EPA Says [DNAinfo]
• Set to scrub: Workers will begin new phase of Gowanus Canal cleanup next week, EPA says [Brooklyn Paper]
• EPA Ready to begin phase 2 of pilot study at Fourth Street Basin [PMFA]
• Uncovering the Gowanus Canal's decades of toxic debris [Curbed]
• All Gowanus Canal coverage [Curbed]