Monday, August 15, 2011

Lower Deschutes Water Temperatures Causing Concern

Anglers on the Lower Deschutes Rivers have been raising concerns recently over what they perceive as elevated temperatures in the river below Round Butte Dam. The problem first arose in 2010 when PGE started operating a multimillion dollar fish collection tower which, rather than releasing water only from the bottom of Lake Billy Chinook, took in some warmer surface water in an attempt to collect downstream migrating smolts. As a result water temperatures increased slightly, alarming some members of the fishing community. With its water typically a few degrees cooler than the stagnant mainstem Columbia, the Deschutes has long served as an important thermal refuge for migrating salmon and steelhead.

Increasing water temperatures from changes in flow releases at Lake Billy Chinook have reduced the number of "dip ins" and occasionally lead to water temperatures in the Lower Deshcutes which can be stressful for salmon and steelhead. Addressing the concerns, PGE has sought to improve their flow management in the Lower Deschutes and ensure that temperatures remain below 70 F, however anglers continue to complain that the warm water is hurting their fishing as this year has seen unusually late runoff and cooler than normal summer temperatures meaning fewer fish are dipping into the Deschutes.

While cool water in the Columbia may hurt fishing on one of the state's most popular rivers, it's a boon to Columbia salmon and steelhead which can more readily migrate to their natal rivers, avoiding thermal blocks, stress and elevated prespawn mortality. More information in the Oregonian:

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