Waita Reservoir Reservoir Report

Last Updated: December 19, 2025

Waita Reservoir in Koloa, Hawaii, is a privately-owned water resource that serves primarily for irrigation purposes.


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Summary

This earth dam, completed in 1906, stands at a height of 23 feet and has a maximum storage capacity of 9,900 acre-feet. With a normal storage capacity of 3,400 acre-feet, the reservoir covers a surface area of 650 acres and drains an area of 3.36 square miles.

Despite being under state regulation and inspection, Waita Reservoir has a high hazard potential and is classified as having a fair condition assessment. The spillway, with a width of 65 feet, is uncontrolled, with a maximum discharge capability of 2,000 cubic feet per second. The last inspection in November 2018 deemed the reservoir to be in fair condition, with a moderate risk assessment rating of 3.

This captivating summary of Waita Reservoir highlights its historical significance, engineering details, and current risk assessment. As a crucial water resource in Koloa, Hawaii, this privately-owned reservoir serves as a vital source of irrigation for the region. With its high hazard potential, state regulation, and fair condition assessment, Waita Reservoir presents a unique blend of challenges and opportunities for water resource and climate enthusiasts to explore and analyze.

Year Completed

1906

Dam Length

3250

Dam Height

23

River Or Stream

WAIHOHONU STREAM OFFSTREAM

Primary Dam Type

Earth

Surface Area

650

Hydraulic Height

27

Drainage Area

3.36

Nid Storage

9900

Structural Height

28

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

28
       
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.