Sly Number 1
Key Takeaway
Sly Number 1 is classified as significant hazard in South Dakota. It was completed in 1961 and is 65 years old. Its primary use is fire protection. Significant hazard means failure could cause economic or environmental damage. Learn more.
Physical Details
| Dam Height | 25 ft (taller than 57.4% in SD) |
| Dam Length | 280 ft |
| Dam Type | Earth |
| Max Storage | 18 acre-ft |
| Normal Storage | 8 acre-ft |
| Max Discharge | 900 cfs |
| Year Completed | 1961 (65 years old) |
| NID ID | SD00224 |
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
GERALD SLY
Private
Nearby Dams
Frequently Asked Questions
What is the hazard classification of Sly Number 1?
Sly Number 1 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 Sly Number 1?
Sly Number 1 is owned by GERALD SLY (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Sly Number 1 built?
Sly Number 1 was completed in 1961, making it 65 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 Sly Number 1?
Sly Number 1 serves the following purposes: Fire Protection, Stock, Or Small Fish Pond. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
How tall is Sly Number 1?
Sly Number 1 has a dam height of 25 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.