Maui Reservoir 90 Reservoir Report
Nearby: Maui Reservoir 92 Maui Reservoir 82
Last Updated: December 20, 2025
Maui Reservoir 90, also known as Hc&S Reservoir 90, is a privately owned water storage facility located in Waiakoa Homesteads, Maui, Hawaii.
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Summary
Built in 1917 for irrigation purposes, this reservoir has a dam height of 13 feet and a hydraulic height of 19 feet, with a maximum storage capacity of 201 acre-feet and a normal storage level of 138 acre-feet. With a surface area of 15.8 acres and a drainage area of 0.5 square miles, this reservoir plays a crucial role in providing water for agricultural activities in the region.
Despite its age, Maui Reservoir 90 is in fair condition and is inspected every five years to ensure its structural integrity and safety. The dam has a high hazard potential, but the risk assessment indicates a moderate level of risk. The spillway type is uncontrolled, with a width of 18 feet, and the reservoir is regulated by the Hawaii Department of Land and Natural Resources (DLNR). Overall, Maui Reservoir 90 serves as a vital water resource for the local community and contributes to the sustainability of agriculture in the area.
As climate change continues to impact water availability and usage patterns, the preservation and maintenance of reservoirs like Maui Reservoir 90 become increasingly important. With its historical significance and continued role in irrigation, this reservoir stands as a testament to the importance of efficient water management practices in the face of changing environmental conditions. By prioritizing inspection, maintenance, and risk management measures, Maui Reservoir 90 exemplifies the proactive approach needed to ensure the long-term sustainability of water resources in Hawaii.
Year Completed |
1917 |
Dam Length |
1250 |
Dam Height |
13 |
River Or Stream |
FED BY IRRIGATION DITCH |
Primary Dam Type |
Earth |
Surface Area |
15.8 |
Hydraulic Height |
19 |
Drainage Area |
0.5 |
Nid Storage |
201 |
Structural Height |
22 |
Hazard Potential |
High |
Foundations |
Unlisted/Unknown |
Nid Height |
22 |
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.
Area Campgrounds
| Location | Reservations | Toilets |
|---|---|---|
maybe camping
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chemin vers la côte
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Kanaha Beach Park - Maui
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papalau camping
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Camp Olowalu
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Camp Olowalu - Maui
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Maui Reservoir 90