Aahoaka Reservoir Reservoir Report

Last Updated: February 5, 2026

Aahoaka Reservoir, located in Wailua, Hawaii, is a state-owned structure primarily used for irrigation purposes.


Summary

Completed in 1910, this earth dam stands at a height of 36 feet with a total length of 550 feet, providing a storage capacity of 210 acre-feet. The reservoir is situated on the TR-Wailua River South Fork, serving as a vital resource for water management in the region.

Despite its historical significance, Aahoaka Reservoir poses a high hazard potential due to its poor condition assessment, with a risk level rated as moderate. The dam is regulated by the Hawaii Department of Land and Natural Resources, which ensures regular inspections and enforcement measures are in place for the safety and maintenance of the structure. In the event of an emergency, the reservoir's Emergency Action Plan is periodically updated to meet guidelines and mitigate risks associated with potential inundation.

With its strategic location and crucial role in water resource management, Aahoaka Reservoir remains a key feature in sustaining agricultural activities and maintaining water supply in Kauai, Hawaii. As climate change continues to impact water availability and infrastructure resilience, ongoing monitoring and management of this reservoir are essential to safeguarding the surrounding community and environment.



°F

°F

mph

Wind

%

Humidity


15-Day Weather Outlook


Year Completed

1910

Dam Length

550

Dam Height

36

River Or Stream

TR-WAILUA RIVER SOUTH FORK

Primary Dam Type

Earth

Surface Area

5.9

Hydraulic Height

36

Drainage Area

0.74

Nid Storage

210

Structural Height

38

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

38
       
Seasonal Comparison

5-Day Hourly Forecast Detail

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.