Wanapum
Key Takeaway
Wanapum is classified as high hazard in Washington. It was completed in 1965 and is 61 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 | 93 ft (taller than 60.9% in WA) |
| Dam Length | 8,639 ft |
| Dam Type | Gravity |
| Max Storage | 796.0K acre-ft |
| Normal Storage | 590.0K acre-ft |
| Surface Area | 14,590 acres |
| Drainage Area | 95,000 sq mi |
| Max Discharge | 1,400,000 cfs |
| Year Completed | 1965 (61 years old) |
| NID ID | WA00085 |
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
Grant County PUD
Public Utility
Nearby Dams
Frequently Asked Questions
What is the hazard classification of Wanapum?
Wanapum 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 Wanapum?
Wanapum is owned by Grant County PUD (Public Utility). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Wanapum built?
Wanapum was completed in 1965, making it 61 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 Wanapum?
Wanapum serves the following purposes: Hydroelectric, Recreation, Flood Risk Reduction. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
How tall is Wanapum?
Wanapum has a dam height of 93 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 Wanapum last inspected?
Wanapum was last inspected on April 3, 2023. Inspection dates indicate when a formal review occurred, not the results of that inspection.