Waikoloa Reservoir No. 3 Reservoir Report
Last Updated: December 24, 2025
Waikoloa Reservoir No.
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Summary
3, also known as Waikoloa 50 Mg Reservoir 3, is a crucial water resource facility located in Hawaii, specifically in the county of Hawaii. Completed in 1985, this earth-type dam stands at a height of 54 feet and has a storage capacity of 190 acre-feet, serving primarily for water supply purposes. With a surface area of 7.25 acres and a drainage area of 0.01 square miles, this reservoir plays a key role in managing water resources in the region.
Despite its significant contribution to water supply, Waikoloa Reservoir No. 3 also poses a high hazard potential, with a fair condition assessment as of March 2020. The dam's spillway type is uncontrolled, with a width of 5 feet, and it is regulated by the Hawaii Department of Land and Natural Resources. Regular inspections are conducted, with the last one taking place in April 2018, and a hazard potential rating of moderate (3) has been assigned to the reservoir, prompting the need for risk management measures to ensure its continued safety and functionality for the surrounding community.
As an essential water management infrastructure in Hawaii, Waikoloa Reservoir No. 3 serves as a lifeline for water supply purposes in the region. With its high hazard potential and fair condition assessment, ongoing monitoring and maintenance are vital to ensure the safety and efficiency of this crucial water resource facility. Climate and water resource enthusiasts can appreciate the intricate workings of this structure, as well as the efforts required to manage and protect it for the benefit of the local community and environment.
Year Completed |
1985 |
Dam Length |
1500 |
Dam Height |
54 |
River Or Stream |
Waikoloa - Off Stream |
Primary Dam Type |
Earth |
Surface Area |
7.25 |
Drainage Area |
0.01 |
Nid Storage |
190 |
Hazard Potential |
High |
Foundations |
Unlisted/Unknown |
Nid Height |
54 |
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.
Waikoloa Reservoir No. 3