LAKE CHELAN –
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Following a decade of restoration work, the Chelan River now has year-round water flows and new habitat for salmon spawning. Given these achievements, the Department of Ecology is considering site-specific water quality standards that reflect the unique nature of the river.
The proposal to revise water quality standards for the river is based on a request from Public Utility District No. 1 of Chelan County (Chelan PUD). Chelan PUD operates a hydropower dam project at the outfall of Lake Chelan to the river. In the late 1990s, as part of the dam relicensing process, Ecology required Chelan PUD to do a 10-year monitoring, evaluation, and adaptive management program to evaluate whether the restoration work would lead to the river supporting salmon spawning and survival. (See October 2020 blog)
“Establishing new salmon habitat on the Chelan River is a great achievement, reflecting years of work by Chelan PUD, fishery managers, tribes, and stakeholders,” said Vince McGowan, Water Quality Program Manager. “These targeted, site-specific updates to water quality standards reflect what conditions we now know are achievable on the river to support salmon spawning, rearing, and migration.”
Ecology is proposing to modify state water quality standards at Chelan PUD’s request. The proposed changes require formal rulemaking and are site-specific, meaning if finalized they would only apply to the Chelan River.
Currently, state water quality standards designate the aquatic life use of salmon spawning, rearing and migration for the entire Chelan River. The designation was assigned by default without an evaluation of whether this use was existing or achievable in the river.
This is the first time Ecology has proposed such a change under a tool provided by Clean Water Act regulations, called a Use Attainability Analysis (UAA). The UAA allows Ecology to “consider the physical, chemical, biological, and economic factors that affect meeting a designated (water quality) use.”
Chelan PUD has requested Ecology conduct a UAA to consider:
- Revisions to the aquatic life use designation to reflect the highest attainable uses in the river; and,
- Site-specific criteria for temperature and dissolved oxygen in the water that protect the highest achievable aquatic life use designations.
Specifically, Chelan PUD is requesting Ecology consider changing the aquatic life use designation to “migration for naturally limited waters” on the upper and middle sections and to “salmonid spawning, rearing, and migration for naturally limited waters” in the lower section of the river. This means there would be different standards for different parts of the river.
Ecology is accepting comment on the draft rulemaking language, including a draft Technical Support Document and draft Implementation Plan until May 21, 2021. Public hearings will take place online on May 11 and 13. All draft documents, hearing information and instructions on how to comment can be found on the rulemaking webpage.
The work completed by the Chelan PUD and the Natural Science Working Group is outlined in the Chelan River Use Attainability Analysis and Site-Specific Criteria Development report, published by the Chelan PUD in December 2019.