Wednesday, June 30, 2010

Fish Passage Underway on the Upper Deschutes

As this years smolt migration winds down, managers at Lake Billy Chinook's newly constructed fish passage facility are nearing their goal of passing 50% of out-migrant smolts through a newly constructed fish collection tower. Anadromous fish were extirpated from the Upper Deschutes in 1964 with the construction of Round Butte Dam, cutting off access to many of the Deschutes' largest tributaries including the Crooked and Metolius River. The project to create a fish passage facility at Round Butte has been a technologically challenging one, made more difficult by density differences in Metolius River water, which being cooler naturally settles to the bottom of the reservoir. In an attempt to address the problem, Portland General Electric built both surface and subsurface fish collection into their smolt intake structure. While 50% is far below an acceptable level for downstream fish passage it represents an important first step towards reintroduction of wild chinook, sockeye and steelhead into the once productive rivers of the Upper Deschutes. Hopefully managers can learn from this season of passage and continue to improve the design and function of the fish collection facility.

More information in the Columbia Basin Bulletin.

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