Not too much, not too little. Not too warm, not too cold. How to get Delaware River water just right

Delaware River just south of Hancock DC
The Delaware River just south of Hancock, N.Y. PHOTO BY MEG MCGUIRE

In some ways, the Delaware River is like a water balloon -- squeeze or release on one end and the other end reacts. The way this happens is often complicated but it's essential to understand how the demands on the river affect all the people who depend on the river, up north, down south or anywhere in the middle!

And one of the ways to see that "squeeze/release" is to sit in on one of the Delaware River Basin Commission's advisory committees that work on the science to suggest policy that the commissioners themselves vote on.

One of them is the Regulated Flow Advisory Committee. 

You can tell a lot about what it does by its title: the flow of the river is not natural, but regulated. It starts with the three New York City water supply reservoirs that capture the headwaters of the Delaware: Neversink, Cannonsville and Pepacton. Those reservoirs must release enough water into the river to keep a certain flow at Montague in New Jersey.

That's one of the ways the river's waters are regulated, and the regulation comes from the U.S. Supreme Court Decree of 1954 when downriver states were concerned about the amount of water "left" in the river if a thirsty New York City drank too much of it. That decision stipulates that enough water is released into the Delaware to meet a minimum flow objective of 1,750 cfs (cubic feet per second) at what is called the Montague gage.

There's another large city that depends on the Delaware's waters -- Philadelphia -- as well as a host of smaller cities and towns. But the quantity of river water is important for another reason: A strong fresh water flow is needed to push back the salt front coming up from the Atlantic Ocean. The Delaware is tidal up to Trenton, N.J., north of Philadelphia. Philadelphia's intake on the Delaware is usually safe from the ocean's salt water, but when there's a drought, that salt front can work its way up the river because the flow of fresh water is weaker.

See how this push-me/pull-me energy can get manifested?

Another wrinkle: this Regulated Flow Advisory Committee is unlike other DRBC committees, inasmuch as it doesn't directly "report" to the DRBC. New York City is a member of RFAC and it is not a member of the commission. The five members of the DRBC are the governors of the river's four border states plus the federal government representative -- the U.S. Army Corps of Engineers. RFAC hosts the decree parties -- the ones subject to that U.S. Supreme Court decree -- the four states and New York City. The details of that decree can't be changed unless there is unanimous agreement from those five parties.

When there was a drought from 1962-1967 -- it's called the drought of record -- it became clear that NYC couldn't withdraw all the water that the Supreme Court's decree gave it a right to and make that flow objective at Montague, N.J.

So the four states that make up 4/5ths of the DRBC began to work with New York City on finding a way to solve that problem, and they created a Good Faith Agreement, then a Flexible Flow Management Program, which "solved" the problem in a short-term way each year, until it didn't in spring 2017.

It took a few months and a lot of nail-biting -- especially in upriver communities -- but there is a whole new 10-year plan in place, under the wing of this committee to study various problems that have been ignored/postponed in the previous short-term planning of the Flexible Flow Management Program. Instead of operating for one year, this FFMP can be operational for 10 years, with lots of evaluations of present and future water systems to form any basis for change.

As part of this new FFMP, there's a whole 'nother committee that was revived to explore a big concern for the northern reaches of the Delaware. It's called the subcommittee on ecological flows (the SEF -- I know, there are lots of names and abbreviations, but this is a complicated river!) and its mandate, to put it really simply, is to address one overarching concern: How much water is needed to keep the northern ecosystem of the river healthy through the warm summer months? Although maybe the underlying question isn't about how much water -- the amount of "extra" water that can be used already has a limit as set forth in the program documents. Maybe the question is: How best to use that water?

Too little water, and the river gets narrow and shallow, and warm. That's hard on fish, of course, but it's hard on all the other river critters. It's especially difficult if there are dramatic changes in volume, so-called yo-yo releases, and especially what are called de-watering events. Those sorts of changes are not natural and many critters can't move quickly enough to a safe place. In a natural river, the change takes place slowly enough for them to move with the water.

So that's the broad area of study for the SEF. (There's going to be a follow-up story to tackle a bit more on that committee in a few days.)

While the upriver folks are studying in minute detail the best way to balance the various needs of the upriver ecology with the needs of NYC, there's another issue that New York City wants addressed: Is there a way to disconnect the New York City reservoirs from the responsibility of the salt line? In fact, the FFMP will:

"...evaluate the impacts and conditions resulting from the following:

  1. The detachment of releases from the New York City Delaware Reservoirs from the position of the salt front during drought emergency and replacing the benefit that New York City releases have with respect to the salt front with an alternative methodology or methodologies that will provide comparable protection for existing resources within the Basin." (Here's the FFMP agreement)

The flow depends largely on the water released from those NYC reservoirs but there are so many variables: How much rain? How full are the reservoirs? How much water comes into the river from the upriver tributaries, like the Lackawaxen, the Mongaup and the flow from the third NYC reservoir, the Neversink?

Also, that be-all, end-all gage is a really long way from the dams. The Montague gage (which is actually in Milford, Pa.) is about a hundred river miles away from the Pepacton dam, and a little less from Cannonsville's dam.

You can see why New York City might be interested in de-coupling from that flow demand, but that change to the decree -- in fact any change to the decree -- must be agreed to by all five decree parties.

The most recent meeting of RFAC on April 9, 2019, got pulled in at least two directions by the push-me/pull-me water concerns of various parties.

The RFAC heard a short update on the work of the SEF, but also one of a series of presentations from the Philadelphia Water Department on its long-range water-supply planning.  

The Philadelphia Water Department has three important issues that would affect its water supply: climate change, ambient water quality changes and policy changes. 

PWD is concerned that de-coupling NYC from the responsibility to keep up the flow targets in Montague will have a negative effect on the ability of the PWD to supply the city's water needs in the future. And here's something to consider: New York City's water-supply folks (New York City Department of Environmental Protection) have a seat on the RFAC since it's one of the decree parties. Philadelphia doesn't. Of course, Philadelphia has a big brother, Pennsylvania, that is.

Ready for another wrinkle? There's always another wrinkle! 

New Jersey takes water from the Delaware to supply drinking water for its citizens. As its population grows, it will likely want more. It has presented the suggestion to RFAC that NYC has water to spare, if it was willing to take water equally from all its reservoirs. New Jersey suggests that the city is taking more water from the "cleaner" waters of the Delaware headwater reservoirs because it's trying to avoid the need for a multi-million dollar filtration system. More info on the Filtration Avoidance Determination here.

It was New Jersey's concerns about its water supply that kiboshed the FFMP in 2017. In a nutshell, New Jersey wants more water. New York City isn't eager to give it to them (and the river as a whole). And New York City's position is understandable, since its first priority is, well, New York City.

OK, back to Philadelphia Water Department and the presentation given by Molly Hesson, water resources consultant to the Philadelphia Water Department (you can see all the slides here).

The title of the presentation says it all: PWD Water Supply Planning: Salinity Intrusion in the Delaware River Estuary.

In a word, its big worry is salt.

If salt water gets into its intake pipes, it will be a disaster for PWD and all the million-plus residents who depend on the river for their drinking water.

But, of course it's not just as simple as ensuring that the salt front stays away from its input.

"Ambient chloride concentrations today are equivalent to the worst salinity intrusion of record in the 1960s," says one slide -- that means that the "fresh" water coming into the river is already saltier than what it was years ago. The main culprit? Road salt.

Road salt that makes the roads safer in winter. This isn't a local problem, but a national one and there are plenty of people trying to figure out how we can be safe and not oversalt our water supplies.

Hesson also explained that there's an area of salty water in the Delaware estuary during the summer months (when freshwater flows tend to be lower) that moves closer up towards Philadelphia when the tide is in, and farther away when the tide is out. It takes the drenching rains of autumn to finally flush that salt plume away and back into the ocean.

One of the slides presented offered a considerable challenge to NYC's wishes to de-couple from its responsibility to push down the salt front:

"Any attempt to alter current flow targets needs a carefully crafted assessment of intrusion impacts on public health and infrastructure."

PWD is developing a model that will help it and RFAC members figure out what the long-term solution might be to conflicting requests. Remember, change has to be agreed to by all the decree parties.

We don't have water wars on the Delaware. We have, instead, the quiet shuffling of bureaucracy in the DMZ of the DRBC. (Look! More alphabet soup!)

About Meg McGuire

Meg McGuire has been a journalist for 30 years in New York and Connecticut. She started in weekly newspapers and moved to full-time work in dailies 25 years ago. She knows about the tectonic changes in journalism firsthand, having been part of what was euphemistically called a "reduction in force" six years ago. Now she's working to find new ways to "do" the news as an independent online publisher of news about the Delaware River, its watershed and its people.


  1. […] We're in a slightly different ball game with the Regulated Flow Advisory Committee, often referred to as a two-syllable acronym: R-FAC. This committee is not "inside" the DRBC as the other committees are. It is composed of the four states but instead of the federal government, New York City is in it. And that's because New York City is one of the five decree parties. And that's all you're going to get here — there's LOTS more in that previous story.  […]

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