Hebgen Dam
Key Takeaway
Hebgen Dam is classified as high hazard in Montana. It was completed in 1915 and is 111 years old. Its primary use is hydroelectric. 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 | 88 ft (taller than 98.7% in MT) |
| Dam Length | 721 ft |
| Dam Type | Earth |
| Max Storage | 525.6K acre-ft |
| Normal Storage | 386.0K acre-ft |
| Surface Area | 13,000 acres |
| Drainage Area | 905 sq mi |
| Max Discharge | 4,400 cfs |
| Year Completed | 1915 (111 years old) |
| NID ID | MT00134 |
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
NorthWestern Energy
Private
Frequently Asked Questions
What is the hazard classification of Hebgen Dam?
Hebgen 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 Hebgen Dam?
Hebgen Dam is owned by NorthWestern Energy (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Hebgen Dam built?
Hebgen Dam was completed in 1915, making it 111 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 Hebgen Dam?
Hebgen Dam serves the following purposes: Hydroelectric, Recreation, Water Supply, Flood Risk Reduction. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
How tall is Hebgen Dam?
Hebgen Dam has a dam height of 88 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 Hebgen Dam last inspected?
Hebgen Dam was last inspected on August 25, 2021. Inspection dates indicate when a formal review occurred, not the results of that inspection.