The U.S. Environmental Protection Agency finalized an agreement with the city of New York that secures the design of the larger of two combined sewage and stormwater overflow retention tanks, which are key components of the Gowanus Canal cleanup effort, including both the tank’s size and location. It also requires New York City to undertake activities to prepare that location for the tank installation and to pay EPA’s oversight costs.

The final administrative agreement and order released June 9 allows New York City to locate an 8-million-gallon retention tank in New York City’s preferred location (known as the “Head-of-Canal” location), but it also holds the city to a strict schedule with monetary penalties imposed if violations of the schedule occur.

Also, the EPA can require New York City to place the tank in the Thomas Greene Park location instead if certain activities do not occur on schedule, including if the city is not able to acquire the land at the Head-of-Canal location within approximately four years. Locations for staging and other work related to the construction of the tank will be acquired by New York City as part of the ongoing design phase of the project.

“The New York City Parks Department prefers not to have a large sewage retention tank permanently located in a city park,” says Judith A. Enck, EPA regional administrator. “The EPA is committed to preserving urban parkland and worked with the city of New York on this alternate location. This alternate location meets the dual goals of cleaning up the canal while also protecting urban parkland.”

More than a dozen contaminants, including polycyclic aromatic hydrocarbons, polychlorinated biphenyls and heavy metals such as mercury, lead and copper, were found at high levels in the sediment in the Gowanus Canal. PAHs and heavy metals were also found in the canal water. PCBs and PAHs are suspected of being cancer-causing and PCBs can have neurological effects as well. To this day, people can still be found fishing in the Gowanus, despite advisories about not eating fish from the canal. In 2010, the Gowanus Canal was added to EPA’s Superfund list of the nation’s most contaminated hazardous substance sites.

The EPA issued its final cleanup plan for the Gowanus Canal Superfund site on Sept. 27, 2013. The cleanup includes dredging contaminated sediment that has accumulated on the bottom of the canal as a result of industrial and sewer discharges. The dredged areas will be capped.

The cleanup plan also calls for the construction of two sewage and stormwater retention tanks to significantly reduce CSO discharges from two key locations in the upper portion of the canal. These discharges are not being addressed by current New York City upgrades to the sewer system. Without these controls, CSO discharges would recontaminate the canal after its cleanup.

The plan includes controls to prevent other land-based sources of contamination from compromising the cleanup. The canal design work is expected to continue for another two years, including a dredging and capping pilot which the EPA expects will be initiated at the 4th Street basin in 2017, followed by the start of full-scale cleanup construction at the top of the canal in 2018.

The EPA’s cleanup plan assumed possible locations for the two tanks, both owned by New York City — the Thomas Greene Park location for the larger tank at the top of the canal and the Department of Sanitation salt storage lot located at 2nd Avenue and 5th Street for the smaller tank in the middle of the canal. 

The cleanup plan specified that the final locations would be determined during the design phase of the project. The EPA and New York City have already agreed that one tank, with a capacity of 4 million gallons, will be located at the Department of Sanitation salt storage lot.

For the larger 8-million-gallon tank at the top of the canal, New York City proposed as its preferred location two adjacent properties on Nevins Street between Butler and DeGraw streets. Under the agreement, the larger tank will be located at the Head-of-Canal location. The agreement also requires the city to carry out actions to prepare that site for installation of the tank, including removal of contaminated soil.

As a contingency, the agreement also requires New York City to work concurrently on a tank design for the Thomas Greene Park location. If the agreement conditions are not met within time frames specified in the agreement, the EPA can require New York City to construct the tank at the Thomas Greene Park location.