Sully Dam
Key Takeaway
Sully Dam is classified as low hazard in South Dakota. It was completed in 1935 and is 91 years old. Its primary use is recreation.
Physical Details
| Dam Height | 17 ft (taller than 20.2% in SD) |
| Dam Length | 952 ft |
| Dam Type | Earth |
| Max Storage | 1.1K acre-ft |
| Normal Storage | 420 acre-ft |
| Max Discharge | 1,599 cfs |
| Year Completed | 1935 (91 years old) |
| NID ID | SD00541 |
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
S&PL
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 S&PL (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 1935, making it 91 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: Recreation. 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 17 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 December 21, 2023. Inspection dates indicate when a formal review occurred, not the results of that inspection.