Guernsey
Key Takeaway
Guernsey is classified as high hazard in Wyoming. It was completed in 1926 and is 100 years old. Its primary use is hydroelectric. 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 | 135 ft (taller than 98.9% in WY) |
| Dam Length | 560 ft |
| Dam Type | Earth |
| Max Storage | 45.6K acre-ft |
| Normal Storage | 45.6K acre-ft |
| Surface Area | 2,380 acres |
| Drainage Area | 15,008 sq mi |
| Max Discharge | 77,800 cfs |
| Year Completed | 1926 (100 years old) |
| NID ID | WY01293 |
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
Nearby Dams
Frequently Asked Questions
What is the hazard classification of Guernsey?
Guernsey 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 Guernsey?
Guernsey is owned by RECLAMATION (Federal Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Guernsey built?
Guernsey was completed in 1926, making it 100 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 Guernsey?
Guernsey serves the following purposes: Hydroelectric, Irrigation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
How tall is Guernsey?
Guernsey has a dam height of 135 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 Guernsey last inspected?
Guernsey was last inspected on June 30, 2020. Inspection dates indicate when a formal review occurred, not the results of that inspection.