Grayrocks
Key Takeaway
Grayrocks is classified as high hazard in Wyoming. It was completed in 1980 and is 46 years old. Its primary use is other. 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 | 95 ft (taller than 98.2% in WY) |
| Dam Length | 2,625 ft |
| Dam Type | Earth |
| Max Storage | 194.0K acre-ft |
| Normal Storage | 104.1K acre-ft |
| Surface Area | 3,547 acres |
| Drainage Area | 4,484 sq mi |
| Max Discharge | 112,300 cfs |
| Year Completed | 1980 (46 years old) |
| NID ID | WY01496 |
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
BASIN ELECTRIC POWER COOPERATIVE
Public Utility
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Low Hazard 20 ftFrequently Asked Questions
What is the hazard classification of Grayrocks?
Grayrocks 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 Grayrocks?
Grayrocks is owned by BASIN ELECTRIC POWER COOPERATIVE (Public Utility). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Grayrocks built?
Grayrocks was completed in 1980, making it 46 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 Grayrocks?
Grayrocks serves the following purposes: Other. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
How tall is Grayrocks?
Grayrocks has a dam height of 95 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 Grayrocks last inspected?
Grayrocks was last inspected on October 6, 2023. Inspection dates indicate when a formal review occurred, not the results of that inspection.