Sully Dam
Key Takeaway
Sully Dam is classified as low hazard in South Dakota. It was completed in 1938 and is 88 years old. Its primary use is water supply.
Physical Details
| Dam Height | 22 ft (taller than 45.6% in SD) |
| Dam Length | 1,470 ft |
| Dam Type | Earth |
| Max Storage | 2.6K acre-ft |
| Normal Storage | 1.2K acre-ft |
| Max Discharge | 9,040 cfs |
| Year Completed | 1938 (88 years old) |
| Year Modified | 2000 |
| NID ID | SD00434 |
Safety Information
No probable loss of human life and low economic/environmental losses expected.
Hazard potential describes downstream consequences of failure, not the dam's current condition. What does this mean?
Ownership
GF&P
State Government
Nearby Dams
Frequently Asked Questions
What is the hazard classification of Sully Dam?
Sully Dam is classified as Low Hazard. No probable loss of human life and low economic/environmental losses expected. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.
Who owns and operates Sully Dam?
Sully Dam is owned by GF&P (State Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Sully Dam built?
Sully Dam was completed in 1938, making it 88 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 Sully Dam?
Sully Dam serves the following purposes: Water Supply. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
How tall is Sully Dam?
Sully Dam has a dam height of 22 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 Sully Dam last inspected?
Sully Dam was last inspected on October 20, 2022. Inspection dates indicate when a formal review occurred, not the results of that inspection.