Tongue River Dam
Key Takeaway
Tongue River Dam is classified as high hazard in Montana. It was completed in 1939 and is 87 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 Height | 93 ft (taller than 98.9% in MT) |
| Dam Length | 1,824 ft |
| Dam Type | Earth |
| Max Storage | 127.7K acre-ft |
| Normal Storage | 79.1K acre-ft |
| Surface Area | 3,700 acres |
| Drainage Area | 1,760 sq mi |
| Max Discharge | 98,000 cfs |
| Year Completed | 1939 (87 years old) |
| Year Modified | 1999 |
| NID ID | MT00002 |
Safety Information
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?
Ownership
STATE WATER PROJECTS
State Government
Nearby Dams
Frequently Asked Questions
What is the hazard classification of Tongue River Dam?
Tongue River 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 Tongue River Dam?
Tongue River Dam is owned by STATE WATER PROJECTS (State Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Tongue River Dam built?
Tongue River Dam was completed in 1939, making it 87 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 Tongue River Dam?
Tongue River Dam serves the following purposes: Irrigation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
How tall is Tongue River Dam?
Tongue River Dam has a dam height of 93 ft. Dam height is measured from the natural streambed at the downstream toe to the top of the dam, and may differ from the visible height.
When was Tongue River Dam last inspected?
Tongue River Dam was last inspected on May 17, 2023. Inspection dates indicate when a formal review occurred, not the results of that inspection.