Helena Valley
Key Takeaway
Helena Valley is classified as high hazard in Montana. It was completed in 1957 and is 69 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 | 94 ft (taller than 98.9% in MT) |
| Dam Length | 1,900 ft |
| Dam Type | Earth |
| Max Storage | 10.7K acre-ft |
| Normal Storage | 10.5K acre-ft |
| Surface Area | 531 acres |
| Drainage Area | 3 sq mi |
| Year Completed | 1957 (69 years old) |
| NID ID | MT00743 |
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
RECLAMATION
Federal Government
Nearby Dams
Frequently Asked Questions
What is the hazard classification of Helena Valley?
Helena Valley 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 Helena Valley?
Helena Valley is owned by RECLAMATION (Federal Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Helena Valley built?
Helena Valley was completed in 1957, making it 69 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 Helena Valley?
Helena Valley serves the following purposes: Irrigation, Water Supply. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
How tall is Helena Valley?
Helena Valley has a dam height of 94 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 Helena Valley last inspected?
Helena Valley was last inspected on July 28, 2020. Inspection dates indicate when a formal review occurred, not the results of that inspection.