The Delaware River. National Park Service photo.

NYC to Adjust Reservoir Releases for Downriver States

The new plan should control the Delaware River's salt line and thereby protect aquatic life and drinking water supply.

New York City has agreed to modifications of releases of water from its reservoir system in the Catskill Mountains to better protect the ecology of the Delaware River in New Jersey and other downriver states, and help provide drought relief and flood protection, according to New Jersey Department of Environmental Protection Commissioner Bob Martin.

The agreement worked out with the New York City Department of Environmental Protection and approved by the four states that share the river basin ─ New Jersey, New York, Pennsylvania and Delaware ─ will better control the river's salt line, typically found in an area around the Delaware Memorial Bridge in Salem County, thereby better protecting aquatic life, as well as drinking-water suppliers and industries that utilize fresh water from the river.

The agreement enables water purveyors in a broad swath of central New Jersey to tap into a larger share of Delaware River water via the Delaware and Raritan Canal. It also calls for the city to test a procedure to help to alleviate threats of flooding along upper portions of the Delaware River.

"This agreement is a perfect example of agencies working together and across state lines to reach a goal that is good for the entire region, one that is consistent with good water supply practices,'' said Martin. "I must commend New York City for working with us toward resolving our concerns with its operating plan for its reservoir system and recognizing that the way the city releases water from its reservoirs is felt many miles downstream."

"This landmark agreement protects New York City's water supply, and at the same time, increases the amount of water available to New Jersey, and will better protect the river's ecology, and help reduce flooding throughout the basin,'' said New York City Environmental Protection Commissioner Cas Holloway.

These steps will take effect June 1. After one year, all the parties will evaluate the reservoir management plan to see how it can be improved.
New York City operates three reservoirs in the Catskill region of southern New York State that are located in the headwaters area of the Delaware River. These reservoirs can store more than 276 billion gallons of water.
New Jersey, New York City, and the states of Delaware, New York and Pennsylvania are all parties to a 1954 federal court Consent Decree allowing for shared management of the Catskill reservoirs. New York City releases water from its Delaware Basin reservoirs as part of court-approved Flexible Flow Management Plan (FFMP). Releases from the city's Delaware reservoirs have been governed by that plan since it was approved by the U.S. Supreme Court in October 2007. The modifications are an update to the FFMP.

Under terms of the modifications:

  • Fishery officials from all four states and the city will form a panel to advise the city on maintaining water flows and temperatures to maintain a healthy and vibrant fishery.
  • New Jersey can increase its diversion via the Delaware and Raritan Canal during drought warnings from 85 million gallons per day to 100 million gallons per day. During drought emergencies, the diversion will remain at 85 million gallons per day.
  • New York City has set an operational goal to maintain its reservoirs at 10 percent below capacity from Sept. 1 to March 15, and an average of 5 percent below capacity from July 1 to Sept. 1 and from March 15 to May 1. That step could help alleviate river flooding during periods of major storms and heavy snow melt.

Using a high-tech modeling tool, the city's Department of Environmental Protection developed a new formula that dramatically improves the ability to forecast and model water conditions, and make decisions on use of shared resources of the Delaware River in a new and better way. That can improve conditions for fish and other aquatic life in the Delaware River and keep the river's salt line in check. During droughts, this area of brackish water can move up the river and potentially affect industrial and drinking water intakes in southern New Jersey.

Source: New Jersey and New York City environmental agencies