Newsletter Sign-up Printer Friendly Format Translate This Page Text Size Small Medium Large


November 30, 2012


Adam Bosch (845) 334-7868

Department of Environmental Protection to Resume Installation of Siphons at Gilboa Dam

New siphons important component of $400 million rehabilitation of Gilboa Dam

The New York City Department of Environmental Protection (DEP) today announced plans to resume the installation of new siphons at Schoharie Reservoir, which will help regulate water levels in the reservoir and allow workers to finish rebuilding the Gilboa Dam. Siphons are steel pipes that draw water out of the reservoir over a barrier.

The three-week-long project will install at least one of two siphons to be added to the dam. Each siphon will be capable of releasing 250 million gallons a day from the reservoir into the Schoharie Creek, allowing DEP to better manage reservoir levels and provide added flood protection downstream. Currently, diverting water through the Shandaken Tunnel and into the Ashokan Reservoir or operating the newly installed crest gates are the only ways to lower water levels.

The new siphons are the latest step in a $400 million full-scale rehabilitation project, which includes reinforcing the dam with 234 million pounds of concrete, reconstructing the spillway and installing a new release tunnel around the dam from the Schoharie Reservoir into Schoharie Creek. The siphons are an important component of the reconstruction plan because they allow DEP to lower water levels, providing workers with access to portions of the dam that would otherwise be obstructed by water. The siphons will also help DEP meet its commitment of lowering the reservoir for snowpack mitigation during winter months – a measure that aims to further reduce spring flooding.

To install the siphons and continue the dam rehabilitation, DEP must lower the elevation of water in the Schoharie Reservoir. On Saturday, DEP will increase the flow of water from the Schoharie Reservoir through the Shandaken Tunnel and begin operational releases from the Ashokan Reservoir. Both actions aim to reduce the water level at Schoharie Reservoir without unnecessarily increasing storage at the Ashokan Reservoir. DEP will run its Operational Support Tool on a regular basis – as often as daily – to gather data and enable the agency to minimize diversions from the Schoharie Reservoir and operational releases at Ashokan.

The diversions have been approved by the New York State Department of Environmental Conservation and the operational releases are in compliance with the Interim Ashokan Release Protocol. DEP staff has reached out to state and local officials to inform them of the releases and pending construction work at Gilboa Dam.

Reconstruction of Gilboa Dam is expected to be finished in 2014, while the new release tunnel is expected to be complete in 2019. The Gilboa Dam was built from 1919 to 1927 and impounds the Schoharie Reservoir, the northernmost reservoir in New York City’s Catskill water supply system.

DEP manages the city’s water supply, providing more than one billion gallons of water each day to more than nine million residents, including eight million in New York City, and residents of Ulster, Orange, Putnam and Westchester counties. This water comes from the Catskill, Delaware, and Croton watersheds that extend more than 125 miles from the City, and the system comprises 19 reservoirs, three controlled lakes, and numerous tunnels and aqueducts. DEP employs nearly 6,000 employees, including approximately 750 scientists, engineers, surveyors, watershed maintainers and other professionals in the upstate watershed. In addition to its $68 million payroll and $153 million in annual taxes paid in upstate counties, DEP has invested more than $1.5 billion in watershed protection programs—including partnership organizations such as the Catskill Watershed Corporation and the Watershed Agricultural Council—that support sustainable farming practices, environmentally sensitive economic development, and local economic opportunity. In addition, DEP has a robust capital program with a planned $13.2 billion in investments over the next 10 years that creates up to 3,000 construction-related jobs per year. For more information, visit, like us on Facebook at, or follow us on Twitter at

More Information

NYC Department of Environmental Protection
Public Affairs

59-17 Junction Boulevard
19th Floor
Flushing, NY 11373

(718) 595-6600