Maui Reservoir 15 Reservoir Report

Last Updated: December 20, 2025

Maui Reservoir 15, also known as Hc&S Reservoir 15, is a privately owned water storage facility situated in Kuau, Maui, Hawaii.


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Summary

Completed in 1917, this earth dam stands at a height of 39 feet and has a storage capacity of 26 acre-feet, serving primarily for irrigation purposes. With a spillway width of 3 feet and a surface area of 1.1 acres, the reservoir is sourced from an unnamed gulch and falls under the jurisdiction of the Hawaii Department of Land and Natural Resources (DLNR).

Despite its age, Maui Reservoir 15 has been deemed to have a high hazard potential and an unsatisfactory condition assessment, prompting regular inspections every 5 years. The dam's risk assessment is moderate, indicating a potential for significant consequences in the event of failure. Managed by private owners, the reservoir's emergency action plan is currently under review, underscoring the importance of ensuring the safety and integrity of this critical water resource infrastructure in the face of climate variability and changing precipitation patterns.

Located in a region vulnerable to the impacts of climate change, Maui Reservoir 15 serves as a significant water source for irrigation in the area, highlighting the need for ongoing maintenance and risk management measures to safeguard against potential hazards and ensure the sustained availability of water resources for agricultural use in the face of evolving environmental conditions.

Year Completed

1917

Dam Length

200

Dam Height

39

River Or Stream

UNNAMED GULCH

Primary Dam Type

Earth

Surface Area

1.1

Hydraulic Height

22

Drainage Area

0.65

Nid Storage

26

Structural Height

32

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

39
       
Seasonal Comparison

Weather Forecast

Dam Data Reference

Condition Assessment

Satisfactory
No 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

High
Dams 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.