Piwai Reservoir
Key Takeaway
Piwai Reservoir is classified as high hazard in Hawaii. It was completed in 1916 and is 110 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 | 56 ft (taller than 88.2% in HI) |
| Dam Length | 535 ft |
| Dam Type | Earth |
| Max Storage | 261 acre-ft |
| Normal Storage | 222 acre-ft |
| Surface Area | 11 acres |
| Drainage Area | 0 sq mi |
| Max Discharge | 487 cfs |
| Year Completed | 1916 (110 years old) |
| NID ID | HI00114 |
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.
Private
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What is the hazard classification of Piwai Reservoir?
Piwai 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 Piwai Reservoir?
Piwai Reservoir is owned by Alexander & Baldwin, Inc. (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Piwai Reservoir built?
Piwai Reservoir was completed in 1916, making it 110 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 Piwai Reservoir?
Piwai 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 Piwai Reservoir?
Piwai Reservoir has a dam height of 56 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 Piwai Reservoir last inspected?
Piwai Reservoir was last inspected on October 11, 2021. Inspection dates indicate when a formal review occurred, not the results of that inspection.