Kaopala Basin Reservoir Report
Last Updated: December 19, 2025
Kaopala Basin, also known as Structure No.
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Summary
4, is a crucial flood risk reduction structure located in the picturesque city of Napili in Maui, Hawaii. Managed by the local government, specifically the Department of Land and Natural Resources (DLNR), this earth dam stands at 30 feet high and spans 250 feet in length. Completed in 1998 by the USDA NRCS, it serves the primary purpose of flood risk reduction along the Kaopala Gulch.
With a storage capacity of 38.4 acre-feet and a drainage area of 0.94 square miles, Kaopala Basin has a spillway width of 50 feet and a high hazard potential due to its location. Despite being rated in fair condition during the latest assessment in April 2021, the structure undergoes inspections every 5 years to ensure its integrity. While the risk assessment categorizes it as moderate, the dam remains a crucial component in managing water resources in the region and mitigating potential flooding events.
As water resource and climate enthusiasts, the Kaopala Basin presents an intriguing case study in flood risk reduction and infrastructure management. Its presence underscores the importance of sustainable water management practices in a changing climate, highlighting the need for continued oversight and maintenance to safeguard both the local community and the surrounding environment from potential hazards.
Year Completed |
1998 |
Dam Length |
250 |
Dam Height |
30 |
River Or Stream |
Kaopala Gulch |
Primary Dam Type |
Earth |
Surface Area |
1.6 |
Drainage Area |
0.94 |
Nid Storage |
38.4 |
Outlet Gates |
Uncontrolled |
Hazard Potential |
High |
Foundations |
Unlisted/Unknown |
Nid Height |
30 |
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.
Kaopala Basin