Omao Reservoir
Key Takeaway
Omao Reservoir is classified as high hazard in Hawaii. It was completed in 1915 and is 111 years old. Its primary use is irrigation. 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 | 40 ft (taller than 65.4% in HI) |
| Dam Length | 454 ft |
| Dam Type | Earth |
| Max Storage | 194 acre-ft |
| Normal Storage | 139 acre-ft |
| Surface Area | 9 acres |
| Drainage Area | 1 sq mi |
| Max Discharge | 3,000 cfs |
| Year Completed | 1915 (111 years old) |
| NID ID | HI00113 |
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
Alexander & Baldwin, Inc., Eric A. Knudsen Trust
Private
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High Hazard 49 ftFrequently Asked Questions
What is the hazard classification of Omao Reservoir?
Omao Reservoir 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 Omao Reservoir?
Omao Reservoir is owned by Alexander & Baldwin, Inc., Eric A. Knudsen Trust (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Omao Reservoir built?
Omao Reservoir was completed in 1915, making it 111 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 Omao Reservoir?
Omao Reservoir serves the following purposes: Irrigation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
How tall is Omao Reservoir?
Omao Reservoir has a dam height of 40 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 Omao Reservoir last inspected?
Omao Reservoir was last inspected on July 1, 2021. Inspection dates indicate when a formal review occurred, not the results of that inspection.