Pia Mill Reservoir
Key Takeaway
Pia Mill Reservoir is classified as high hazard in Hawaii. It was completed in 1910 and is 116 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 | 17 ft (taller than 7.1% in HI) |
| Dam Length | 450 ft |
| Dam Type | Earth |
| Max Storage | 39 acre-ft |
| Normal Storage | 31 acre-ft |
| Surface Area | 6 acres |
| Drainage Area | 0 sq mi |
| Max Discharge | 440 cfs |
| Year Completed | 1910 (116 years old) |
| NID ID | HI00115 |
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
Eric A. Knudsen Trust
Private
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High Hazard 70 ftFrequently Asked Questions
What is the hazard classification of Pia Mill Reservoir?
Pia Mill 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 Pia Mill Reservoir?
Pia Mill Reservoir is owned by Eric A. Knudsen Trust (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Pia Mill Reservoir built?
Pia Mill Reservoir 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 Pia Mill Reservoir?
Pia Mill 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 Pia Mill Reservoir?
Pia Mill Reservoir has a dam height of 17 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 Pia Mill Reservoir last inspected?
Pia Mill Reservoir was last inspected on July 1, 2021. Inspection dates indicate when a formal review occurred, not the results of that inspection.