Thief Valley Reservoir Report
Nearby: Little Park Dam Wirth Reservoir
Last Updated: December 14, 2025
Thief Valley is a Federal-owned dam located in Oregon along the Powder River, designed by the Bureau of Reclamation and completed in 1931 for the primary purpose of irrigation.
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Summary
This Buttress-type dam stands at 66 feet high with a storage capacity of 20,495 acre-feet and a surface area of 807 acres. The dam plays a vital role in managing water resources in the region, with a high hazard potential due to its location and design.
Managed by the Bureau of Reclamation, Thief Valley undergoes regular inspections to ensure its structural integrity and safety. Although the condition assessment is currently unavailable, emergency action preparedness is a key consideration for this dam, given its high hazard potential. The dam's importance for irrigation and water management in the area highlights the need for ongoing monitoring and risk management measures to protect surrounding communities and infrastructure.
Thief Valley's location in Union, Oregon, under the jurisdiction of the Portland District, emphasizes its significance in regulating water flow and storage along the Powder River. With a history dating back to the early 20th century, this dam continues to fulfill its purpose of providing critical water resources for irrigation while facing the challenges of aging infrastructure and potential hazards. As water resource and climate enthusiasts, understanding the role and management of dams like Thief Valley is essential for sustainable water management practices in the face of changing environmental conditions.
Year Completed |
1931 |
Dam Length |
390 |
Dam Height |
66 |
River Or Stream |
POWDER RIVER |
Primary Dam Type |
Buttress |
Surface Area |
807 |
Hydraulic Height |
58 |
Drainage Area |
914 |
Nid Storage |
20495 |
Structural Height |
73 |
Hazard Potential |
High |
Foundations |
Rock |
Nid Height |
73 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Dam Data Reference
Condition Assessment
SatisfactoryNo 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
HighDams 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.
Area Campgrounds
| Location | Reservations | Toilets |
|---|---|---|
Catherine Creek State Park
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North Fork Catherine Creek Campground
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Catherine Creek
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North Fork Catherine Creek Group Campground
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Thief Valley