Upper Sunshine
Key Takeaway
Upper Sunshine is classified as high hazard in Wyoming. It was completed in 1942 and is 84 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 | 154 ft (taller than 99.2% in WY) |
| Dam Length | 1,150 ft |
| Dam Type | Earth |
| Max Storage | 65.1K acre-ft |
| Normal Storage | 53.0K acre-ft |
| Surface Area | 1,156 acres |
| Drainage Area | 13 sq mi |
| Max Discharge | 1,520 cfs |
| Year Completed | 1942 (84 years old) |
| Year Modified | 1974 |
| NID ID | WY01097 |
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
GREYBULL VALLEY IRRIGATION DISTRICT
Private
Nearby Dams
Frequently Asked Questions
What is the hazard classification of Upper Sunshine?
Upper Sunshine 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 Upper Sunshine?
Upper Sunshine is owned by GREYBULL VALLEY IRRIGATION DISTRICT (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Upper Sunshine built?
Upper Sunshine was completed in 1942, making it 84 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 Upper Sunshine?
Upper Sunshine 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 Upper Sunshine?
Upper Sunshine has a dam height of 154 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 Upper Sunshine last inspected?
Upper Sunshine was last inspected on May 13, 2021. Inspection dates indicate when a formal review occurred, not the results of that inspection.