Protecting trout in the Delaware

By LIAM MAYO
Posted 11/8/22

NARROWSBURG, NY — The modern world has given humanity power over even an environment as natural as the Delaware River; people can influence everything, from how the river flows to how warm the …

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Protecting trout in the Delaware

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NARROWSBURG, NY — The modern world has given humanity power over even an environment as natural as the Delaware River; people can influence everything, from how the river flows to how warm the river gets.   

The Upper Delaware Council (UDC) heard a presentation on using that power for good from Dr. Peter Kolesar at its November 3 meeting.

Kolesar, a professor at Columbia University, has a long history of advocating for the health of the Upper Delaware and for the safety of its trout population. His work formed the basis for the 2007 Flexible Flow Management Program (FFMP), a document that guides releases of water from the Delaware River’s reservoirs.

During the summer, when the air and the water of the Upper Delaware warm up, they reach temperatures that can be lethal for the river’s trout, said Kolesar. Between 2008 and 2018 there were 78 days when temperatures exceeded 75 degrees Fahrenheit, a dangerous temperature for the river’s trout stock.

To help with that issue, Kolesar helped implement a thermal mitigation protocol as an addendum to the FFMP.

That protocol provides for a limited number of releases from the Delaware River reservoirs for the protection of the trout. On very hot days, the New York State Department of Environmental Conservation (DEC) can authorize the release of cool water from the reservoirs, bringing temperatures down below the danger point.

The protocol has its limits. There isn’t enough water in the reservoirs to protect the entire river, so it focuses on daily temperatures at Lordville. It takes a while for water from the reservoirs to reach Lordville, so the DEC has to predict when releases will be needed and plan accordingly. The DEC has a limited budget to work with in making its predictions; the protocol gives the DEC a set amount of water from June 1 to May 31 the following year, and its releases have to be limited so as to not run this bank dry.

Releases are a gamble, said Kolesar. That gamble largely worked out in 2022.

During the summer of 2022, the DEC called for 23 releases and kept temperatures below 75 degrees all days except for four, on which the highest temperature reached was 76.5 degrees Fahrenheit. “Each one of these four days, they tried,” said Kolesar; the DEC had made releases, it just hadn’t quite released enough.

Kolesar had analyzed the summer’s releases and found that had the DEC not made its releases, an additional nine days would have gone above 75 degrees. Conversely, about seven of the releases the DEC made probably weren’t necessary; the river would likely have stayed below 75 degrees with or without them.

All told, the thermal mitigation protocol has been operating since 2019 and has been reasonably successful, said Kolesar.

The effects of climate change on the Upper Delaware complicate this picture going forward.

This was a strange, hot, dry summer, said Kolesar. June was cooler and wetter than during a normal year, and July and August were dryer and hotter. Kolesar projected a decade ahead from past regional data and estimated an increase in summer average daily temperatures of 0.24 degrees, an increase in the number of summer days over 80 degrees of 0.75, an increase in the amount of summer rain by 1.9 inches and a rise in daily water temperatures at Callicoon of 0.14 degrees.

Kolesar thanked the UDC for the advocacy work it had done in the past, and identified a number of areas in the thermal mitigation protocol that required further study: Was 75 degrees the ideal target temperature? Was the bank of water the DEC could use large enough, or was the bank structure itself the wrong way to approach the protocol? And could shorter pulses of releases save the river’s trout while using less water?

These were questions of more than theoretical impact. UDC chairperson Andy Boyar pointed out that the Delaware’s fishery was the best in the East, and that it was an untapped economic engine.

Revisiting fracking

During the meeting’s public comment period, Damascus Citizens for Sustainability director Barbara Arrindell pressed the council to support a full ban on fracking byproducts in the Delaware River.

The Delaware River Basin Commission (DRBC) banned fracking in the river basin in February of 2021, but allowed with conditions the import of fracking wastewater into the Delaware River basin and the export of Delaware River water for use in fracking.

Arrindell asked the UDC to send a letter requesting that the DRBC ban all fracking byproducts in the basin.

Boyar asked what the timeline was for such a letter.

The DRBC could call a special meeting to address the question, but it needed pressure from individuals and agencies to do so, said Arrindell.

The UDC recessed discussion of the request to a Tuesday, November 15 meeting of the council’s water use and resource management committee.

Dr. Peter Kolesar, Flexible Flow Management Program, thermal mitigation protocol, Delaware River, trout, fracking, fracking wastewater

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