Willow Butte Reservoir Report

Last Updated: December 13, 2025

Willow Butte is a gravity dam located in Harney County, Oregon, that serves as a vital water supply source in the region.


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Summary

Completed in 2004 by the Bureau of Land Management, this dam has a hydraulic height of 20 feet and a structural height of 25 feet, with a total length of 840 feet. It has a storage capacity of 16.4 acre-feet and covers a surface area of 2.1 acres, making it an essential infrastructure for water management in the area.

Despite being classified as having a low hazard potential, Willow Butte dam is considered to be in fair condition, with a very high risk assessment rating of 1. The dam is regularly inspected every 5 years, with the last inspection conducted in September 2019. With a controlled spillway type and a maximum discharge capacity of 816 cubic feet per second, the dam plays a crucial role in mitigating flood risks and ensuring water availability for the surrounding areas. It stands as a testament to the Bureau of Land Management's commitment to water resource management and climate resilience in Oregon.

Overall, Willow Butte represents a significant investment in water infrastructure by the federal government, providing essential water supply services to the region. With its sturdy construction and functional design, the dam serves as a critical asset for water resource and climate enthusiasts alike, highlighting the importance of sustainable water management practices in ensuring the resilience of communities in the face of changing environmental conditions.

Years Modified

2001 - Structural

Year Completed

2004

Dam Length

840

River Or Stream

UNNAMED TO WILLOW CREEK

Primary Dam Type

Gravity

Surface Area

2.1

Hydraulic Height

20

Drainage Area

0.86

Nid Storage

16.4

Structural Height

25

Hazard Potential

Low

Foundations

Unlisted/Unknown

Nid Height

25
       
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.