River Mill
Key Takeaway
River Mill is classified as high hazard in Oregon. It was completed in 1911 and is 115 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 | 85 ft (taller than 93% in OR) |
| Dam Length | 936 ft |
| Dam Type | Buttress |
| Normal Storage | 2.3K acre-ft |
| Surface Area | 150 acres |
| Drainage Area | 671 sq mi |
| Max Discharge | 150,000 cfs |
| Year Completed | 1911 (115 years old) |
| NID ID | OR00552 |
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
Portland General Electric Company
Private
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Low Hazard 25 ftFrequently Asked Questions
What is the hazard classification of River Mill?
River Mill 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 River Mill?
River Mill is owned by Portland General Electric Company (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was River Mill built?
River Mill was completed in 1911, making it 115 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 River Mill?
River Mill serves the following purposes: Hydroelectric, Recreation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
How tall is River Mill?
River Mill has a dam height of 85 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 River Mill last inspected?
River Mill was last inspected on September 20, 2022. Inspection dates indicate when a formal review occurred, not the results of that inspection.