Nuuanu Dam No. 4
Key Takeaway
Nuuanu Dam No. 4 is classified as high hazard in Hawaii. It was completed in 1910 and is 116 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 | 66 ft (taller than 92.1% in HI) |
| Dam Length | 2,120 ft |
| Dam Type | Earth |
| Max Storage | 3.6K acre-ft |
| Normal Storage | 242 acre-ft |
| Surface Area | 25 acres |
| Drainage Area | 1 sq mi |
| Max Discharge | 4,000 cfs |
| Year Completed | 1910 (116 years old) |
| NID ID | HI00001 |
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
Honolulu Board of Water Supply
Local Government
Nearby Dams
Frequently Asked Questions
What is the hazard classification of Nuuanu Dam No. 4?
Nuuanu Dam No. 4 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 Nuuanu Dam No. 4?
Nuuanu Dam No. 4 is owned by Honolulu Board of Water Supply (Local Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Nuuanu Dam No. 4 built?
Nuuanu Dam No. 4 was completed in 1910, making it 116 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 Nuuanu Dam No. 4?
Nuuanu Dam No. 4 serves the following purposes: Flood Risk Reduction. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
How tall is Nuuanu Dam No. 4?
Nuuanu Dam No. 4 has a dam height of 66 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 Nuuanu Dam No. 4 last inspected?
Nuuanu Dam No. 4 was last inspected on February 4, 2021. Inspection dates indicate when a formal review occurred, not the results of that inspection.