Osullivan
Key Takeaway
Osullivan is classified as high hazard in Washington. It was completed in 1948 and is 78 years old. Its primary use is flood risk reduction. 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 | 200 ft (taller than 79.3% in WA) |
| Dam Length | 19,000 ft |
| Dam Type | Earth |
| Max Storage | 546.3K acre-ft |
| Normal Storage | 511.7K acre-ft |
| Surface Area | 27,800 acres |
| Drainage Area | 4,000 sq mi |
| Max Discharge | 30,850 cfs |
| Year Completed | 1948 (78 years old) |
| NID ID | WA00268 |
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
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What is the hazard classification of Osullivan?
Osullivan 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 Osullivan?
Osullivan is owned by RECLAMATION (Federal Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Osullivan built?
Osullivan was completed in 1948, making it 78 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 Osullivan?
Osullivan serves the following purposes: Flood Risk Reduction, Irrigation, Navigation, Hydroelectric. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
How tall is Osullivan?
Osullivan has a dam height of 200 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 Osullivan last inspected?
Osullivan was last inspected on June 3, 2020. Inspection dates indicate when a formal review occurred, not the results of that inspection.