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August 23, 2017
deppressoffice@dep.nyc.gov, (845) 334-7868

NYC DEP to Suspend Voluntary Releases of Water from Delaware System Reservoirs

The New York City Department of Environmental Protection (NYCDEP) today announced that it will suspend voluntary releases of additional water from its Delaware System reservoirs and ramp down to minimum rates of release that are outlined in the interstate agreement that currently regulates flows on the Delaware River.

NYCDEP will make this change in two steps. On Sept. 5, it will reduce releases of water from Cannonsville, Pepacton and Neversink reservoirs to those outlined in Table A of the Flexible Flow Management Program (FFMP). Exact release rates on that date will be determined by reservoir storage. The City will then further reduce its releases on Oct. 10 to meet the minimums outlined in Revision 1, the 1983 program that currently regulates flows on the Delaware River. Charts showing the release rates from Cannonsville, Pepacton and Neversink reservoirs are included below.

NYCDEP began to voluntarily release additional water from its Delaware System reservoirs in June after the City and the states of Delaware, New Jersey, New York and Pennsylvania failed to renew the existing flow management program for the Delaware River, or agree on a new program. The stalemate in negotiations required management of the Delaware River to revert to Revision 1, a program that was developed 34 years ago without the benefit of modern science and modeling.

The older program, which became effective this year on June 1, included minimum releases rates that were significantly less than the amount of water typically released from New York City’s reservoirs into the headwaters of the Delaware River. In most cases the amount of water released from the City’s reservoirs during the summer would have been cut by more than half. Reverting to the older management plan also eliminated a program that seasonally required 10-percent voids in the City’s three reservoirs to enhance the flood attenuation that their dams already provide.

To prevent the undue harm of lower flows during the peak of summer, New York City announced in June that it would voluntarily release quantities of water above the minimum targets outlined in Revision 1 to support the world-class fishery on the upper Delaware River and the tourism businesses that rely on river recreation.

The following is a statement from NYCDEP Deputy Commissioner Paul Rush on the City’s decision to suspend those voluntary releases in the weeks ahead:

“The voluntary release of additional cold water into the Delaware River over the past 12 weeks marked a deliberate effort by New York City to prevent undue harm to the world-class trout fishery and businesses in New York and Pennsylvania during a time when thousands of visitors are arriving to enjoy the region’s natural resources. However, these additional releases of water were never meant to be a long-term substitute for the type of unanimous agreement, between the states and the City, that the U.S. Supreme Court envisioned in its 1954 decree. As we move past the near-term challenges of the peak of summer, the City believes it is appropriate to return its operations to the model of unanimous consent that has guided flows in the Delaware River for decades. Just as our voluntary releases sought to lessen the sudden impact of dropping to Revision 1, our changes now will also be carefully timed and staged. The City will wait until after Labor Day weekend to reduce its releases. It will also ramp the releases down in two stages to avoid a sudden and significant change in the headwaters of the river. As we take this action, New York City also remains fully engaged in productive negotiations with the four states. The past three months have brought significant progress, and we hope a new flow program for the Delaware River will be agreed upon in short order.”

Additional background information

The terms of a 1954 decree by the U.S. Supreme Court control the flow management regime affecting diversions and releases, on the Delaware River, by the City of New York and the State of New Jersey. The states of Delaware, New Jersey, New York and Pennsylvania and the City are all parties to that decree. A 1961 interstate compact provides the Delaware River Basin Commission with general authority over flow management on the Delaware River, but, under the terms of the compact, variations of flows and releases that affect the City or New Jersey must have the unanimous consent of the decree parties.

The most recent program, known as the Flexible Flow Management Program (FFMP), was collaboratively created by the parties in 2007 and first implemented in 2008. It was renewed by all five Decree Parties on an annual basis until this year.

The FFMP took advantage of an advanced modeling tool built and managed by NYCDEP. The tool, called the Operations Support Tool (OST), incorporates advanced runoff forecasts, streamflow and snowpack measurements, drinking water demand, operational rules and other data. The advanced modeling tool allowed the Decree Parties to design the FFMP by accounting for the drinking water needs of New York City and releasing downstream any excess water from its three reservoirs on the headwaters of the Delaware River.

As a result, the FFMP resulted in the release of more cold water throughout the year than any flow management programs that preceded it. This additional water released downstream helped to support the cold-water trout fishery that attracts an estimated $10 million in annual economic activity to Delaware River communities, and it also supported boating and other tourism activities along the river. The FFMP was also the first flow management program to include void space in the reservoirs to enhance the downstream flood protection that is already provided by their dams. The program required a 10 percent void in New York City’s three Delaware basin reservoirs from October-March.

In recent years, the Decree Parties had adopted some changes to the FFMP and agreed to several one-year extensions of the program. However, FFMP was terminated this year when the five parties failed to unanimously renew it or approve a new flow program. As a result, the FFMP (paragraph 21) requires that the Decree Parties revert to “Revision 1,” a flow program that was designed and implemented in 1983. Revision 1 provides significantly lower downstream releases and does not include a flood mitigation program.

Release tables

The following three table outline releases from New York City’s three reservoirs—Cannonsville, Pepacton and Neversink—on the headwaters of the Delaware River. The first table shows the rate of voluntary releases that NYCDEP was making as of Aug. 20. The second and third tables show what those release rates will drop to when the first reduction is made on Sept. 5 and the final reduction is made to meet the minimums of Revision 1 on Oct. 10.

Voluntary Releases made by NYC as of August 20

  Aug. 20
Cannonsville 323 mgd (500 cfs)
Pepacton 97 mgd (150 cfs)
Neversink 97 mgd (150 cfs)

Voluntary Releases made by NYC starting Sept. 5 under Table A

  Sept. 5
Cannonsville 178 mgd (275 cfs)
Pepacton 97 mgd (150 cfs)
Neversink 65 mgd (100 cfs)

Release Rates under Revisions 1

  Aug. 16–Oct. 31 Nov. 1–March 31
Cannonsville 29 mgd (45 cfs) 21 mgd (33 cfs)
Pepacton 45 mgd (70 cfs) 32 mgd (50 cfs)
Neversink 29 mgd (45 cfs) 16 mgd (25 cfs)

DEP manages New York City’s water supply, providing more than 1 billion gallons of high-quality water each day to more than 9.5 million New Yorkers. This includes more than 70 upstate communities and institutions in Ulster, Orange, Putnam and Westchester counties who consume an average of 110 million total gallons of drinking water daily from New York City’s water supply system. 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 has nearly 6,000 employees, including almost 1,000 scientists, engineers, surveyors, watershed maintainers and other professionals in the watershed. In addition to its $70 million payroll and $166 million in annual taxes paid in upstate counties, DEP has invested more than $1.7 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 $20.7 billion in investments planned over the next 10 years that will create up to 3,000 construction-related jobs per year. For more information, visit nyc.gov/dep, like us on Facebook, or follow us on Twitter.

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