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July 19, 2010


Farrell Sklerov / Mercedes Padilla  (718) 595-6600

DEP Reaches Key Milestone in Gowanus Canal Water Quality Improvement Project

Activation of New Aeration System Allows Upgrade of Flushing Tunnel To Begin

Environmental Protection Commissioner Cas Holloway, local elected officials and community stakeholders today announced the activation of a new oxygenation system, a key milestone in the City's project to improve water quality in the Gowanus Canal. The temporary system will add dissolved oxygen to the canal to help mitigate odors during the upgrade of the century-old Gowanus Canal Flushing Tunnel over the next 26 months. The new oxygenation system is part of a project originally announced by Mayor Bloomberg in October 2009. The project will upgrade the canal's wastewater pumping station to reduce combined sewer overflows in the canal by increasing pumping capacity to the Red Hook Wastewater Treatment Plant, and will upgrade the existing flushing tunnel to significantly increase the flow of oxygen-rich water from Buttermilk Channel in the harbor to the canal. Future work includes dredging sediment at the upper end of the canal to eliminate odors that can arise at low tide, which must be coordinated with the Superfund cleanup process currently being undertaken by the U.S. Environmental Protection Agency.

"Just seven months ago Mayor Bloomberg broke ground on this $140 million project that will dramatically improve water quality in Gowanus Canal," said Commissioner Holloway, "and the activation of this aeration system marks a major milestone that will enable us to begin the rehabilitation of the Flushing Tunnel. Once complete, this upgrade will open up new recreational opportunities and significantly improve the quality of life of those who live nearby."

"It is extremely gratifying to see significant progress being made in the rehabilitation of the Gowanus Canal after so many years of neglect. I congratulate the DEP on reaching this milestone and look forward to even more good news as the DEP works with the EPA to restore this critical Brooklyn waterway," said New York State Senator Velmanette Montgomery of the
18th Senate District.

"The Gowanus Canal Community Development Corporation is thrilled to mark this significant milestone in the upgrade of the canal's flushing tunnel.  Though the road to a clean and rejuvenated canal is long, we have never been so close. I want to thank the City for following through on its commitment, and we look forward to working together to transform this area," said Gowanus Canal Community Development Corporation Executive Director Bill Appel.

The new oxygenation system will duplicate the effects of the flushing tunnel while it is out of service in order to reduce odor conditions in the canal. The system withdraws water from the canal, supersaturates it with oxygen, and discharges it back to the canal through 2,500 feet of piping. This system will allow the tunnel to be dewatered so that construction of the new wastewater force main and upgraded flushing tunnel pumping system can begin. DEP will continually monitor the performance of the oxygenation system during the shutdown of the flushing tunnel.

The overall project is scheduled for completion in 2013.  It will reduce combined sewer overflows into the canal, reduce the floatable debris associated with combined sewer overflows, decrease pathogen concentration, and enhance dissolved oxygen levels in the canal. Once complete, it is expected that the waterway will meet recreational standards for boating and fishing, an improvement from the current fish survival classification. The project has three main components:

Wastewater Pumping Station

  • $85 million upgrade at the head of the canal.
  • Installation of four new pumps to increase combined sewer overflow pumping capacity by 50 percent, from 20 million to 30 million gallons a day.
  • Construction of a mile-long sewage pipe to the Red Hook Wastewater Treatment Plant to reduce combined sewer overflows into the canal.
  • The upgrades are expected to reduce combined sewer overflows into the canal by approximately 34 percent.

Flushing Tunnel

  • $50 million upgrade of the flushing tunnel, which pulls water from Buttermilk Channel into the head of the canal.
  • Water from the Buttermilk Channel in the East River, is oxygen-rich and pumping it into the canal improves overall water quality and mitigates the effects of combined sewer overflows.
  • The existing single pump will be replaced with three pumps, increasing the daily flow of oxygen rich-water into the canal by 40 percent, from 154 million gallons a day to 215 million gallons a day.
  • The tunnel was opened nearly 100 years ago, fell into disrepair, and became inoperable in the 1960s. The tunnel was reactivated 10 years ago.


  • 750 feet of the canal bed's upper reaches will be dredged.
  • The dredging will remove sediment mounds that are exposed during low tides, and eliminate a potential source of odors.
  • Will be coordinated with the EPA's remedy chosen in the Superfund process.

DEP manages the City's water supply, providing more than 1 billion gallons of water each day to more than 9 million residents, including 8 million in New York City, and residents of Ulster, Orange, Putnam and Westchester counties. New York City's water is delivered from a watershed that extends more than 125 miles from the City, and comprises 19 reservoirs, and three controlled lakes.

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