Chief Joseph Dam
Key Takeaway
Chief Joseph Dam is classified as high hazard in Washington. It was completed in 1955 and is 71 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 Length | 4,300 ft |
| Dam Type | Gravity |
| Max Storage | 593.0K acre-ft |
| Normal Storage | 516.0K acre-ft |
| Surface Area | 8,400 acres |
| Drainage Area | 75,400 sq mi |
| Max Discharge | 1,200,000 cfs |
| Year Completed | 1955 (71 years old) |
| NID ID | WA00299 |
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
USACE - Seattle District
Federal Government
Frequently Asked Questions
What is the hazard classification of Chief Joseph Dam?
Chief Joseph Dam 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 Chief Joseph Dam?
Chief Joseph Dam is owned by USACE - Seattle District (Federal Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Chief Joseph Dam built?
Chief Joseph Dam was completed in 1955, making it 71 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 Chief Joseph Dam?
Chief Joseph Dam serves the following purposes: Hydroelectric, Recreation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
When was Chief Joseph Dam last inspected?
Chief Joseph Dam was last inspected on June 21, 2022. Inspection dates indicate when a formal review occurred, not the results of that inspection.