Milles Lake Dam

About Milles Lake Dam

The primary purpose of Milles Lake Dam is fish and wildlife pond. The dam creates habitat for fish and wildlife, supporting local ecosystems and potentially serving conservation goals. The dam is owned by Wa Dfw (state). It impounds the Unnamed Tr. -twisp R. near Twisp.

The dam stands 6 feet tall and stretches 250 feet across, creates a reservoir covering 27 acres, has a maximum storage capacity of 29 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1950, the structure is well-established, with more than 75 years of service.

This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. Its condition is rated satisfactory, indicating no existing or potential dam safety deficiencies are recognized. An emergency action plan is in place for this dam. The most recent inspection on record was 10/24/2023.

Living Downstream

If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The Washington dam safety program can provide more specific information about emergency planning for this structure.

Search for dams near your address to see all dams in your area with hazard classifications and safety data.