Pa Aalii Reservoir

About Pa Aalii Reservoir

Pa Aalii Reservoir is a dam in Hawaii, Hawaii. The dam is owned by Pr Mauna Kea, Llc (private). It impounds the Kohakohau Stream, Three Stream Diversions near Waikoloa Village.

The dam stands 40 feet tall and stretches 745 feet across, has a maximum storage capacity of 96 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1940, the structure is well-established, with more than 75 years of service.

This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. Its condition is rated fair — the dam has minor deficiencies that are being addressed or do not pose an immediate safety threat. Notably, no emergency action plan is currently on file for this high-hazard dam. The most recent inspection on record was 02/17/2024.

At 40 feet, this dam is taller than 87% of dams nationwide.

Living Downstream

If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The Hawaii dam safety program can provide more specific information about emergency planning for this structure.

Search for dams near your address to see all dams in your area with hazard classifications and safety data.