The Washington Department of Ecology is proposing to ease water quality standards for aquatic life in the Chelan River after an analysis for the Chelan County PUD showed a natural barrier prevents use by summer Chinook, steelhead and cutthroat trout in the river's upper reaches.

After the PUD built a new channel and restored the lower half-mile of the river, the analysis showed that section of river was used by summer Chinook and steelhead—but not cutthroat trout—for spawning, rearing and migration from mid-autumn to mid-spring.

Just 4-miles long from the Lake Chelan dam to the Columbia River, the Chelan River had not been analyzed for aquatic uses in 2006, when the PUD's Lake Chelan Hydroelectric Project was relicensed. By default, the river's aquatic life standard was designated for salmonid spawning, rearing and migration.

Under new requirements stemming from a settlement agreement, Ecology's water quality certification and the new FERC license, Chelan PUD worked for 10 years with state and federal agencies, tribes and stakeholders to develop plans and implement several measures to attempt to restore summer Chinook, steelhead and cutthroat trout in the river. According to the analysis, the working group recognized that even with restored flows, the natural physical conditions of the river limited the suitability of habitat for fish.

Marcie Clement, Chelan PUD's water resources program manager, said in addition to the physical barriers, the temperature of Lake Chelan in the summer raises the temperature of the river to levels too warm for salmonids. "This is kind of a unique scenario where the [river] water may even be warmer if the dam wasn't there," she told Clearing Up.

The proposed revisions reflect the highest attainable uses in the river, with site-specific criteria for temperature and dissolved oxygen, according to the analysis.

Under a request from the PUD, Ecology is proposing to modify the water quality standard in the lower half-mile of the Chelan River to support salmonid spawning, rearing and migration for naturally limited waters, and designate the upper river to support downstream migration for naturally limited waters.

It's the first time Ecology would use a provision of the Clean Water Act to reduce water quality standards of a state water body because the standards are unattainable. The agency is accepting comments on the proposal until May 21, and will host online public hearings on May 11 and 13.

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K.C. Mehaffey covers fish issues for Clearing Up, and is editor of the NW Fishletter. She joined the NewsData writing team in February 2018. From lawsuits to scientific studies, she is enjoying the deep dive into the Columbia Basin's many fish topics.