Maunaolu Reservoir Reservoir Report
Nearby: Kemoo 5 Reservoir Wahiawa Dam
Last Updated: December 19, 2025
Maunaolu Reservoir, located in Makaha, Hawaii, is a vital water resource managed by the local government for irrigation purposes.
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Summary
Built in 1966, this earth dam structure stands at a height of 27 feet and spans 800 feet in length, with a storage capacity of 23 acre-feet. The reservoir serves as a key component in the diversion of water from the Glover Tunnel to support agricultural activities in the region.
Despite its fair condition assessment in 2012, Maunaolu Reservoir is classified as having a high hazard potential, necessitating regular inspections every 5 years to ensure its structural integrity and safety. The spillway type is marked as uncontrolled, highlighting the need for ongoing risk management measures to mitigate potential hazards. The reservoir's location in a climate-vulnerable area like Hawaii also underscores the importance of monitoring and adaptive strategies in the face of changing weather patterns and hydrological conditions.
Overall, Maunaolu Reservoir remains a crucial infrastructure for water management in Honolulu County, supporting local agriculture and irrigation needs. As climate change impacts continue to pose challenges to water resources, sustainable management practices and risk assessment measures will be essential to safeguarding the reservoir's functionality and ensuring long-term water security for the community.
Year Completed |
1966 |
Dam Length |
800 |
Dam Height |
27 |
River Or Stream |
Diversion - Glover Tunnel |
Primary Dam Type |
Earth |
Surface Area |
2.3 |
Nid Storage |
23 |
Hazard Potential |
High |
Foundations |
Unlisted/Unknown |
Nid Height |
27 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Makaha Str Nr Makaha
|
16cfs |
Sf Kaukonahua Str At E Pump
|
34cfs |
Opaeula Str Nr Wahiawa
|
27cfs |
Kamananui Str At Maunawai
|
84cfs |
Waikele Str At Waipahu
|
115cfs |
Kamananui Str At Pupukea Mil Rd
|
15cfs |
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.
Maunaolu Reservoir