In an effort to determine how a proposal to rebuild the damaged Eightmile Lake Dam would affect the environment, the Washington Department of Ecology and Icicle and Peshastin Irrigation Districts will jointly develop an environmental impact statement.
In the spring of 2018, floodwaters and runoff overtopped Eightmile Dam.
The high-risk, 90-year-old dam, located in the Alpine Lake Wilderness Area, needs to be rebuilt to protect downstream property and maintain reliable irrigation water supplies for area farmers.
Ecology is accepting comments on what should be included in the scope of a full environmental impact statement (EIS).
As the dam owner, the Icicle and Peshastin Irrigation Districts have worked with Ecology to identify and analyze potential design alternatives to rebuild the dam and bring it up to current safety requirements.
In the fall of 2017, the Jack Creek Fire severely burnt a large portion of the watershed down to the water’s edge, increasing the likelihood of much higher runoff coming into Eightmile Lake. Having already suffered damage in earlier flooding, the dam at the lake was at high risk of complete failure, thus prompting the irrigation districts and Chelan County to declare a state of emergency in spring 2018.
Investigations by Ecology’s Dam Safety Office led to the dam’s designation as a high hazard for failure and a threat to people and property downstream.
“Before we begin work on the EIS, we are asking the community, stakeholders, tribes and others to weigh in on what should be studied, and what types of mitigation should be considered,” said Melissa Downes, with Ecology’s Office of Columbia River.
The EIS will examine the probable, significant and adverse impacts resulting from the construction and rebuild of the dam. It also will analyze how impacts can be reduced or eliminated through mitigation.
Two virtual meetings are scheduled for 3-6 p.m., Wednesday, Jan. 13, and 5-8 p.m., Thursday, Jan. 21. Please visit Ecology’s website (ecology.wa.gov/eightmile) to review project information, submit comments, and register to attend virtual public meetings online.
The comment period will run 45 days, concluding on Feb. 1, 2021.
Repairs to the 90-year-old dam in 2018 were intended to temporarily increase the safety of the dam by widening and hardening the spillway and by replacing a damaged segment of the outlet pipeline that had completely collapsed. The dam has historically provided water for downstream farmers and predates the Wilderness Area designation. The irrigation districts have retained access to the dam under a special warranty deed with the US Forest Service.
Ecology’s Office of Columbia River, in consultation with the Dam Safety Office, will work with the Icicle and Peshastin Irrigation Districts to prepare the full environmental review of the project alternatives. A final EIS is expected to be completed by the end of 2021.
An EIS is an impartial, comprehensive study used as a resource for decision-makers and the public. Permit decisions will be made after completion of the EIS.