Ecology releases final environmental review of proposal to rebuild Eightmile Lake Dam

LEAVENWORTH -- The Washington Department of Ecology issued the final environmental impact statement (EIS) for the rebuild and restoration of Eightmile Dam, a 95-year-old dam located in the Alpine Lakes Wilderness Area west of Leavenworth.

Eightmile Dam is owned by the Icicle and Peshastin Irrigation Districts (IPID) and provides water to many local farms. Damaged by several natural events over the decades, Eightmile Dam has lost water storage capacity. Ecology’s dam safety office reclassified the dam in 2018 due to the increased number of people living downstream, meaning the dam no longer meets current standards. It must be rebuilt to meet dam safety standards in order to protect downstream residents and properties, as well as maintain durable irrigation water supplies for area farms.

The EIS examines the significant adverse environmental impacts of three alternatives for rebuilding the dam, as well as the impacts of operating the current dam with no changes. The EIS also identifies whether mitigation measures could reduce or eliminate those impacts.

Ecology released a draft EIS in April 2023 and held three public meetings during a 45-day comment period. The agency received 6,942 comments, many of which focused on the dam’s appearance and concerns that a rebuilt dam would detract from the wilderness experience.

IPID, in coordination with Ecology, has selected Alternative 2 as the preferred alternative for reconstructing the dam. This alternative includes a wide spillway without gates. It will restore the storage capacity of the lake to meet irrigation and storage needs while minimizing the dam’s visibility to hikers.

IPID will finalize the engineering design for the preferred alternative in the coming months. Construction will not occur this summer.

Learn more about the Eightmile Dam rebuild and restoration and the final EIS on Ecology’s website: ecology.wa.gov/eightmile.