Maui Reservoir 30 Reservoir Report
Nearby: Maui Reservoir 20 Maui Reservoir 22
Last Updated: December 19, 2025
Maui Reservoir 30, also known as Hc&S Reservoir 30, is a privately owned irrigation reservoir located in Haliimaile, Maui, Hawaii.
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Summary
Constructed in 1917, this Earth dam stands at 23 feet high, with a hydraulic height of 16 feet and a structural height of 28 feet. With a storage capacity of 101 acre-feet, this reservoir serves the primary purpose of irrigation and covers a surface area of 9 acres. The reservoir is regulated, permitted, inspected, and enforced by the Hawaii Department of Land and Natural Resources (DLNR).
Despite its fair condition assessment, Maui Reservoir 30 poses a high hazard potential, emphasizing the need for regular inspections and maintenance. The spillway type is uncontrolled, with a width of 9 feet, and the reservoir has a drainage area of 0.03 square miles. The last inspection took place in August 2020, with a scheduled inspection frequency of every 5 years. The risk assessment for this reservoir is moderate, with no assigned DSAC date and limited information on risk management measures in place.
Water resource and climate enthusiasts monitoring Maui Reservoir 30 should be aware of its historical significance and current operational status. With its location in the Kailua Gulch offstream, this reservoir plays a vital role in supporting agricultural irrigation in the region. While the reservoir's condition is deemed fair, ongoing risk assessments and maintenance efforts are necessary to ensure the safety and sustainability of this critical water resource infrastructure in Maui, Hawaii.
Year Completed |
1917 |
Dam Length |
1100 |
Dam Height |
23 |
River Or Stream |
KAILUA GULCH OFFSTREAM |
Primary Dam Type |
Earth |
Surface Area |
9 |
Hydraulic Height |
16 |
Drainage Area |
0.03 |
Nid Storage |
101 |
Structural Height |
28 |
Hazard Potential |
High |
Foundations |
Unlisted/Unknown |
Nid Height |
28 |
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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