Angostura
Key Takeaway
Angostura is classified as high hazard in South Dakota. It was completed in 1949 and is 77 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 | 193 ft (taller than 99.9% in SD) |
| Dam Length | 2,030 ft |
| Dam Type | Concrete |
| Max Storage | 197.1K acre-ft |
| Normal Storage | 86.2K acre-ft |
| Surface Area | 4,706 acres |
| Drainage Area | 9,034 sq mi |
| Max Discharge | 248,000 cfs |
| Year Completed | 1949 (77 years old) |
| NID ID | SD01099 |
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
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Low Hazard 28 ftFrequently Asked Questions
What is the hazard classification of Angostura?
Angostura 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 Angostura?
Angostura is owned by RECLAMATION (Federal Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Angostura built?
Angostura was completed in 1949, making it 77 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 Angostura?
Angostura serves the following purposes: Irrigation, Recreation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
How tall is Angostura?
Angostura has a dam height of 193 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 Angostura last inspected?
Angostura was last inspected on August 26, 2020. Inspection dates indicate when a formal review occurred, not the results of that inspection.