Ecology Releases Environmental Impact Statement For Rebuilding Of Eightmile Dam

The Washington Department of Ecology has issued its final Environmental Impact Statement (EIS) for the reconstruction and restoration of Eightmile Dam.

The 95-year-old structure located in the Alpine Lakes Wilderness area west of Leavenworth has been damaged by several natural events over the decades and is losing its capacity to store water.

Ecology’s office of dam safety reclassified the dam in 2018, which required it to be rebuilt due to an increase in the number of people living downstream, as well as to maintain irrigation water supplies for area farms.

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Chelan County Commissioner Shon Smith says the statement is a critical step in the process to bring the dam back to acceptable standards.

"What it does is give the opportunity for the communities that are engaged or acknowledged within the project the confirmation that the pristine Alpine Wilderness area they live within needs to be protected. And it provides the best methods to still fulfill the rights and privileges of the irrigators and the agricultural providers within our communities."

The dam is owned by the Icicle and Peshastin Irrigation Districts (IPID), and Smith says the County's role in its rebuilding process is also very important.

"The County is just assisting in this project. It's not a County project but it's assisting with the Icicle and Peshastin Irrigation Districts to help with the grant and funding agreements processes, since we're very good at administering those."

The EIS examined the potential environmental impacts of three proposed plans for rebuilding the dam, as well as the impacts of operating the current dam with no changes. It also identified if those impacts could be minimized or eliminated.

The IPID has selected a proposal for rebuilding the dam that includes a wide spillway without gates that will restore the storage capacity of the lake to meet irrigation needs, while also minimizing the dam’s visibility to recreationists in the area.

In April, 2023, Ecology released a draft of the EIS and held three public meetings during a 45-day comment period, during which the agency received nearly 7,000 responses, many of which focused on the dam’s appearance and concerns that a rebuilt dam would detract from the area's natural beauty.

Smith says the design and engineering steps for the dam's reconstruction will begin soon but construction will not start until sometime next year.

He's optimistic the project will be completed by 2026.