Kapalaalaea Reservoir Reservoir Report

Last Updated: December 20, 2025

Kapalaalaea Reservoir, located in Huelo, Maui, Hawaii, is a historic earth dam completed in 1885 primarily for irrigation purposes.


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Summary

This private reservoir, standing at a height of 50 feet and length of 230 feet, has a storage capacity of 197 acre-feet and a surface area of 8.7 acres. Situated along the Papalua Stream, the reservoir plays a crucial role in supporting agricultural activities in the region, with a drainage area of 0.89 square miles.

Despite its age, Kapalaalaea Reservoir is subject to regular state inspections, with the latest assessment in April 2021 deeming its condition unsatisfactory and highlighting a high hazard potential. The reservoir has an uncontrolled spillway, a spillway width of 50 feet, and a moderate risk assessment rating. While the dam's risk management measures and emergency preparedness protocols are not specified in the data, its significance in sustaining local irrigation needs underscores the importance of ensuring its structural integrity and safety in the face of climate change impacts on water resources. Enthusiasts of water resource management and climate resilience will find Kapalaalaea Reservoir to be a compelling case study in balancing the historic significance of water infrastructure with contemporary challenges in maintaining its functionality and safety.

Year Completed

1885

Dam Length

230

Dam Height

48

River Or Stream

PAPALUA STREAM

Primary Dam Type

Earth

Surface Area

8.7

Hydraulic Height

45

Drainage Area

0.89

Nid Storage

197

Structural Height

50

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

50
       
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.