The Dalles, Ore. -- Warmer than usual water temperatures on the lower Deschutes River have raised concerns among guides, anglers and fishery managers, but they have not affected the fishing or the health of the fish.
“According to our creel surveys, steelhead fishing on the lower Deschutes in July has been very good,” said Rod French, ODFW district fish biologist. “There appears to be fish entering the river and we haven’t seen any additional signs of stress or disease because of warm water temperatures.”
The slightly warmer temperatures experienced this July may be, in-part, the result of warmer water being released from the Pelton Round Butte hydroelectric project, about 100 miles upstream of the mouth. The warmer water releases are part of a program being implemented by Portland General Electric and the Confederated Tribes of the Warm Springs Reservation of Oregon to meet water quality standards by restoring seasonal temperature patterns that would be expected to occur if the dams were not there. These measures are required under the terms of the project’s federal operating license.
“Every year we experience warm water temperatures on the Deschutes, this year we’re seeing them a little earlier as a result of the Round Butte project,” French said.
Water temperatures could start to go down in August when day length becomes shorter, and a colder mix of water is released from the dam.
In coordination with the Oregon Department of Environmental Quality and ODFW, PGE operators continue to monitor river temperatures below the hydro project and began this weekend to adjust the mix of water being released from the dam to restore more natural water temperatures.
While the warm water temperatures have not yet affected fish health, extended periods of water temperatures above 70F can be harmful, French said.
“While we haven’t seen much impact yet, we will be monitoring the situation closely,” he said.
In the meantime, anglers fishing when water temperatures area above 70F should take the following precautions:
- Fish during the cooler times of the day, usually mornings and evenings
- Use barbless hooks, play and land the fish quickly
- When releasing wild fish, keep them in the water as much as possible
French also suggests moving higher up the river where water temperatures are cooler and fish may be holding.