Thornton Lake Dam
Key Takeaway
Thornton Lake Dam is classified as significant hazard in Montana. It was completed in 1904 and is 122 years old. Its primary use is irrigation. Significant hazard means failure could cause economic or environmental damage. Learn more.
Physical Details
| Dam Height | 11 ft (taller than 8.4% in MT) |
| Dam Length | 315 ft |
| Dam Type | Rockfill |
| Normal Storage | 243 acre-ft |
| Surface Area | 31 acres |
| Drainage Area | 11 sq mi |
| Year Completed | 1904 (122 years old) |
| NID ID | MT01143 |
Safety Information
No probable loss of human life, but can cause economic loss, environmental damage, or disruption of lifeline facilities.
Hazard potential describes downstream consequences of failure, not the dam's current condition. What does this mean?
Ownership
DONALD W BECK
Private
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Low Hazard 11 ftFrequently Asked Questions
What is the hazard classification of Thornton Lake Dam?
Thornton Lake Dam is classified as Significant Hazard. No probable loss of human life, but can cause economic loss, environmental damage, or disruption of lifeline facilities. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.
Who owns and operates Thornton Lake Dam?
Thornton Lake Dam is owned by DONALD W BECK (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Thornton Lake Dam built?
Thornton Lake Dam was completed in 1904, making it 122 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 Thornton Lake Dam?
Thornton Lake 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 Thornton Lake Dam?
Thornton Lake Dam has a dam height of 11 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 Thornton Lake Dam last inspected?
Thornton Lake Dam was last inspected on August 11, 2014. Inspection dates indicate when a formal review occurred, not the results of that inspection.