Koolau Reservoir

S Fork Kaukonahua· Honolulu, Hawaii· Built 1919· Earth· 70 ft tall
Low Hazard Other Federal Government

Key Takeaway

Koolau Reservoir is classified as low hazard in Hawaii. It was completed in 1919 and is 107 years old. Its primary use is other.

Physical Details

Dam Height 70 ft (taller than 93.7% in HI)
Dam Length270 ft
Dam TypeEarth
Max Storage138 acre-ft
Normal Storage122 acre-ft
Surface Area5 acres
Year Completed1919 (107 years old)
NID IDHI00156

Safety Information

Low Hazard

No probable loss of human life and low economic/environmental losses expected.

Hazard potential describes downstream consequences of failure, not the dam's current condition. What does this mean?

Emergency Action Plan: No
Last Inspection: June 22, 2022
State Regulated: Yes
Regulatory Agency: DLNR

Ownership

Schofield Barracks

Federal Government

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Koolau Reservoir?

Koolau Reservoir is classified as Low Hazard. No probable loss of human life and low economic/environmental losses expected. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.

Who owns and operates Koolau Reservoir?

Koolau Reservoir is owned by Schofield Barracks (Federal Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Koolau Reservoir built?

Koolau Reservoir was completed in 1919, making it 107 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 Koolau Reservoir?

Koolau Reservoir serves the following purposes: Other. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

How tall is Koolau Reservoir?

Koolau Reservoir has a dam height of 70 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 Koolau Reservoir last inspected?

Koolau Reservoir was last inspected on June 22, 2022. Inspection dates indicate when a formal review occurred, not the results of that inspection.

Data from the National Inventory of Dams (NID) maintained by the US Army Corps of Engineers. Dam conditions may have changed since the last update. This site is not affiliated with USACE. Do not use for emergency planning — contact your local dam safety program.