Development No. 1 Dam
Key Takeaway
Development No. 1 Dam is classified as high hazard in Oregon. It was completed in 1929 and is 97 years old. Its primary use is water supply. 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 97.8% in OR) |
| Dam Length | 970 ft |
| Dam Type | Concrete |
| Max Storage | 33.8K acre-ft |
| Normal Storage | 26.6K acre-ft |
| Surface Area | 386 acres |
| Drainage Area | 75 sq mi |
| Max Discharge | 21,000 cfs |
| Year Completed | 1929 (97 years old) |
| NID ID | OR00327 |
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
City of Portland Oregon
Local Government
Nearby Dams
Development No. 2 Dam
Clackamas, OR
High Hazard 145 ftHeadworks Diversion Dam
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Low Hazard 30 ftWahkeena Rearing Reservoir
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Low Hazard 19 ftDuncan Creek Dam
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Low HazardOsburn Reservoir
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Low Hazard 34 ftLake Roslyn
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Significant Hazard 45 ftIsakson Reservoir
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Low Hazard 27 ftFrequently Asked Questions
What is the hazard classification of Development No. 1 Dam?
Development No. 1 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 Development No. 1 Dam?
Development No. 1 Dam is owned by City of Portland Oregon (Local Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Development No. 1 Dam built?
Development No. 1 Dam was completed in 1929, making it 97 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 Development No. 1 Dam?
Development No. 1 Dam serves the following purposes: Water Supply, Hydroelectric. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
How tall is Development No. 1 Dam?
Development No. 1 Dam 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 Development No. 1 Dam last inspected?
Development No. 1 Dam was last inspected on May 24, 2022. Inspection dates indicate when a formal review occurred, not the results of that inspection.