Waikamoi Reservoirs Reservoir Report
Last Updated: December 19, 2025
Waikamoi Reservoirs, also known as Waikamoi Circular Reservoirs, are vital water supply structures located in Kailua, Maui, Hawaii.
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Summary
Completed in 1980, these earth-type dams play a crucial role in storing water for the local government, with a maximum storage capacity of 97.6 million gallons. The reservoirs cover a surface area of 3.7 acres and have a significant hazard potential, with a poor condition assessment as of October 2020.
Despite their importance for water supply, Waikamoi Reservoirs face challenges in terms of maintenance and safety. The dams have a spillway type of uncontrolled and a spillway width of 3 feet, contributing to their moderate risk assessment level. With a height of 20 feet and a length of 921 feet, these reservoirs require regular inspections, with the last one conducted in April 2019. The local government, specifically the Department of Land and Natural Resources, regulates and inspects the site to ensure its proper functioning and mitigate any potential risks associated with its operation.
For water resource and climate enthusiasts, Waikamoi Reservoirs serve as a fascinating example of infrastructure designed to support water supply in a region prone to variable environmental conditions. As the structures continue to play a critical role in water management in Maui, it is essential for stakeholders to prioritize maintenance and monitoring efforts to ensure the long-term sustainability of these reservoirs. By understanding the unique challenges and risks associated with Waikamoi Reservoirs, enthusiasts can advocate for effective management practices that promote water security and resilience in the face of a changing climate.
Year Completed |
1980 |
Dam Length |
921 |
Dam Height |
20 |
Primary Dam Type |
Earth |
Surface Area |
3.7 |
Drainage Area |
0.01 |
Nid Storage |
97.6 |
Hazard Potential |
Significant |
Foundations |
Unlisted/Unknown |
Nid Height |
20 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Dam Data Reference
Condition Assessment
SatisfactoryNo existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
Fair
No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action. Note: Rare or extreme event is defined by the regulatory agency based on their minimum
Poor A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency. Investigations and studies are necessary.
Unsatisfactory
A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
Not Rated
The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.
Not Available
Dams for which the condition assessment is restricted to approved government users.
Hazard Potential Classification
HighDams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
Significant
Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environment damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
Low
Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
Undetermined
Dams for which a downstream hazard potential has not been designated or is not provided.
Not Available
Dams for which the downstream hazard potential is restricted to approved government users.
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