Howard A. Hanson Dam
Key Takeaway
Howard A. Hanson Dam is classified as high hazard in Washington. It was completed in 1962 and is 64 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 Length | 500 ft |
| Dam Type | Rockfill |
| Max Storage | 136.7K acre-ft |
| Normal Storage | 26.0K acre-ft |
| Surface Area | 20,000 acres |
| Drainage Area | 221 sq mi |
| Max Discharge | 129,000 cfs |
| Year Completed | 1962 (64 years old) |
| NID ID | WA00298 |
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
Nearby Dams
Frequently Asked Questions
What is the hazard classification of Howard A. Hanson Dam?
Howard A. Hanson 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 Howard A. Hanson Dam?
Howard A. Hanson Dam is owned by USACE - Seattle District (Federal Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Howard A. Hanson Dam built?
Howard A. Hanson Dam was completed in 1962, making it 64 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 Howard A. Hanson Dam?
Howard A. Hanson Dam serves the following purposes: Flood Risk Reduction, Fish And Wildlife Pond, Water Supply. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
When was Howard A. Hanson Dam last inspected?
Howard A. Hanson Dam was last inspected on October 10, 2021. Inspection dates indicate when a formal review occurred, not the results of that inspection.