UPPER DELAWARE VALLEY — Trout-fishing enthusiasts have long had a goal of keeping water temperatures in a stretch of the Upper Delaware River cool enough during heat waves to protect the health of the trout and ensure the survival of the cold-water fishery.

There is some consensus among those who are concerned with the issue that if the water temperature in the river rises above 75 degrees Fahrenheit, the trout are under severe stress. Because of the abundance of cold water at the bottom of the Cannonsville Reservoir, trout enthusiasts say that with limited releases during heat waves, it is possible to keep temperatures in the river’s Main Stem above Lordville, and in the West Branch, at 75 degrees or below.

In the days leading up to last week’s heat wave, members of the Delaware Watershed Conservation Coalition (DWCC) scrambled to get action from the people responsible for making the decision regarding the releases. Because of the history of the river, and the bureaucratic framework that governs reservoir releases, that is not always an easy thing to do.

The decision about the cool water release is ultimately made by people known as “principles,” who are representatives of the governors of New York, Pennsylvania, New Jersey, Delaware, and also a representative from the New York City Department of Environmental Preservation.

Those five people must all agree on the release before it can be put into effect. As this heat wave was starting, which seemed certain to result in a “thermal stress event,” DWCC put out a press release saying they contacted the relevant parties in New York and Pennsylvania, who in turn conferred with representatives of the other states and ultimately obtained agreement on a release of 300 cubic feet per second for 48 hours. But the conservation groups had to scramble to get it accomplished.

The release succeeded almost completely in keeping temperatures at Lordville below the critical 75 degree level, with the exception of about an hour on Friday, July 17 during which the gage read 75.02 degrees (23.9 centigrade).

A statement from Jeff Skelding, executive director of Friends of the Upper Delaware River, read, “We’re grateful that the governing agencies and key personnel that oversee the river responded to our concerns, particularly Leroy Young at the Pennsylvania Fish and Boat Commission, who initiated the formal request for more cold water, and Paul Rush at the New York City Department of Environmental Protection, who spearheaded the multi-state cooperation necessary for approval,”

But the release added, “‘The frustrating part is that there is plenty of cold water available, and it should have been released prior to air temperatures reaching 90-plus degrees,’ said Lee Hartman of the Pennsylvania Council of Trout Unlimited.” Reservoir levels before the releases were four percentage points above the levels normal for this time of year.

At a meeting of the Water Use Resource Management Committee of the Upper Delaware Council (UDC) on July 16, Columbia professor emeritus Peter Kolesar said that, since 2007, there have been 21 thermal stress events, and each associated heat wave had been accurately predicted by the National Weather Service. He and others have been lobbying officials to adopt a program that would automatically trigger releases from the reservoir when a heat wave is coming, but earlier this year officials said they preferred to consider the releases on a “case-by-case” basis.

Members of the UDC agreed to re-affirm their position that they are in favor of adopting the Thermal Stress Relief Protocol created by Kolesar and Jim Serio.

On July 22, Skelding said the release from the reservoir had the intended effect, and kept the water temperature at just under 75 degrees.