Nilan East Dam
Key Takeaway
Nilan East Dam is classified as high hazard in Montana. It was completed in 1951 and is 75 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 | 51 ft (taller than 97% in MT) |
| Dam Length | 1,010 ft |
| Dam Type | Earth |
| Max Storage | 15.6K acre-ft |
| Normal Storage | 10.1K acre-ft |
| Surface Area | 525 acres |
| Drainage Area | 4 sq mi |
| Max Discharge | 8,620 cfs |
| Year Completed | 1951 (75 years old) |
| Year Modified | 2000 |
| NID ID | MT00014 |
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
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Low Hazard 18 ftFrequently Asked Questions
What is the hazard classification of Nilan East Dam?
Nilan East 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 Nilan East Dam?
Nilan East Dam is owned by STATE WATER PROJECTS (State Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Nilan East Dam built?
Nilan East Dam was completed in 1951, making it 75 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 Nilan East Dam?
Nilan East 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 Nilan East Dam?
Nilan East Dam has a dam height of 51 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 Nilan East Dam last inspected?
Nilan East Dam was last inspected on October 5, 2023. Inspection dates indicate when a formal review occurred, not the results of that inspection.