Milles Lake Dam

Unnamed Tr. -Twisp R.· Okanogan, Washington· Built 1950· Earth·
High Hazard Fish And Wildlife Pond Irrigation State Government

Key Takeaway

Milles Lake Dam is classified as high hazard in Washington. It was completed in 1950 and is 76 years old. Its primary use is fish and wildlife pond. High hazard means loss of life is likely if the dam fails — it does not indicate the dam's current condition. Learn more.

Physical Details

Dam Length250 ft
Dam TypeEarth
Max Storage29 acre-ft
Normal Storage22 acre-ft
Surface Area27 acres
Drainage Area1 sq mi
Max Discharge172 cfs
Year Completed1950 (76 years old)
NID IDWA01788

Safety Information

High Hazard

Loss of human life is likely if the dam fails.

Hazard potential describes downstream consequences of failure, not the dam's current condition. What does this mean?

Emergency Action Plan: Yes
Last Inspection: April 12, 2024
State Regulated: Yes
Regulatory Agency: Washington Dept of Ecology

Ownership

WA DFW

State Government

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Milles Lake Dam?

Milles Lake Dam is classified as High Hazard. Loss of human life is likely if the dam fails. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.

Who owns and operates Milles Lake Dam?

Milles Lake Dam is owned by WA DFW (State Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Milles Lake Dam built?

Milles Lake Dam was completed in 1950, making it 76 years old. Many U.S. dams were built between the 1930s and 1970s during a period of major infrastructure investment.

What is the primary purpose of Milles Lake Dam?

Milles Lake Dam serves the following purposes: Fish And Wildlife Pond, Irrigation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

When was Milles Lake Dam last inspected?

Milles Lake Dam was last inspected on April 12, 2024. Inspection dates indicate when a formal review occurred, not the results of that inspection.

Data from the National Inventory of Dams (NID) maintained by the US Army Corps of Engineers. Dam conditions may have changed since the last update. This site is not affiliated with USACE. Do not use for emergency planning — contact your local dam safety program.