Stemilt Main Dam

Orr Creek-Offstream· Chelan, Washington· Built 1962· Earth·
High Hazard Irrigation Public Utility

Key Takeaway

Stemilt Main Dam is classified as high hazard in Washington. It was completed in 1962 and is 64 years old. Its primary use is irrigation. 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 Length1,000 ft
Dam TypeEarth
Max Storage670 acre-ft
Normal Storage580 acre-ft
Surface Area23 acres
Drainage Area0 sq mi
Max Discharge20 cfs
Year Completed1962 (64 years old)
NID IDWA00014

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: October 30, 2023
State Regulated: Yes
Regulatory Agency: Washington Dept of Ecology

Ownership

Lower Stemilt Irrigation District

Public Utility

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Stemilt Main Dam?

Stemilt Main 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 Stemilt Main Dam?

Stemilt Main Dam is owned by Lower Stemilt Irrigation District (Public Utility). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Stemilt Main Dam built?

Stemilt Main Dam was completed in 1962, making it 64 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 Stemilt Main Dam?

Stemilt Main Dam serves the following purposes: Irrigation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

When was Stemilt Main Dam last inspected?

Stemilt Main Dam was last inspected on October 30, 2023. 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.