Ecology requests input on a draft environmental impact statement (EIS) for rebuilding Eightmile Dam, a 90-year-old dam in the Alpine Lakes Wilderness west of Leavenworth.
Eightmile Dam was damaged as a result of the 2017 Jack Creek fire. Emergency repairs were made in 2018. These repairs address the immediate threat of dam failure, but are not adequate under current dam safety requirements. The dam needs to be rebuilt to current safety standards to protect human health and safety, protect downstream property, and maintain reliable irrigation water supplies for area farmers.
The Icicle and Peshastin Irrigation Districts (IPID) has undertaken preliminary analysis and planning toward bringing the dam into compliance. IPID and Ecology have worked together to identify the environmental impacts of three action alternatives and a “no action” alternative (as required under the State Environmental Policy Act). The alternatives balance three priorities:
- Protecting the integrity of the Alpine Lakes Wilderness
- Ensuring public safety by meeting current dam safety requirements
- Providing durable solutions for water management and delivery
The three alternatives evaluated in the draft Environmental Impact Statement are:
- Alternative 1: Narrow spillway with gates
- Alternative 2: Wide spillway without gates
- Alternative 3: Narrow spillway without gates
- No Action Alternative: Operating the current dam with no changes
Reconstructing the aging dam structure at Eightmile Lake is crucial to protecting downstream residents, the water use of area irrigators and the natural shorelines and habitats of Icicle Creek.
The EIS helps inform what conditions may be required when state and local jurisdictions consider permits. It is not a decision document and does not determine whether a project moves forward. Implementation of any of the action alternatives would require a number of permits and approvals from federal, state and local jurisdictions prior to construction.