Garrison Dam

MISSOURI RIVER· Mercer, North Dakota· Built 1953· Earth·

Key Takeaway

Garrison Dam is classified as high hazard in North Dakota. It was completed in 1953 and is 73 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 Length11,300 ft
Dam TypeEarth
Max Storage26.0M acre-ft
Normal Storage18.5M acre-ft
Surface Area133,000 acres
Drainage Area180,940 sq mi
Max Discharge827,000 cfs
Year Completed1953 (73 years old)
NID IDND00145

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: June 30, 2023
State Regulated: Yes

Ownership

USACE - Omaha District

Federal Government

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Garrison Dam?

Garrison 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 Garrison Dam?

Garrison Dam is owned by USACE - Omaha District (Federal Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Garrison Dam built?

Garrison Dam was completed in 1953, making it 73 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 Garrison Dam?

Garrison Dam serves the following purposes: Irrigation, Recreation, Flood Risk Reduction, Navigation, Hydroelectric. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

When was Garrison Dam last inspected?

Garrison Dam was last inspected on June 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.