Willow Creek Flat Dam (Valley) Reservoir Report
Nearby: Road Reservoir Pines Dam
Last Updated: December 19, 2025
Willow Creek Flat Dam (Valley) is a gravity-type structure located in Valley, Montana, managed by the Bureau of Land Management.
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Summary
This dam, with a hydraulic height of 11 feet and a structural height of 16 feet, serves as a barrier on an intermittent river or stream, providing storage of 170.32 acre-feet for the surrounding area. Despite its low hazard potential, the condition assessment of the dam is marked as unsatisfactory, indicating a need for attention to ensure its safety and functionality.
The dam features an uncontrolled spillway and is constructed with buttress and stone core types. It spans 823 feet in length and covers a surface area of 36.57 acres, with a drainage area of 1.1 square miles. The last inspection of the dam took place in October 2017, with a scheduled inspection frequency of every five years. While the risk assessment categorizes the dam's risk as moderate, further risk management measures and condition assessments are necessary to maintain its integrity and safety for the community and ecosystem it serves.
Overall, Willow Creek Flat Dam showcases the intricate balance between water resource management and climate resilience. As a federal-owned structure under the jurisdiction of the Bureau of Land Management, it highlights the importance of proper maintenance, inspection, and risk management practices. With its specific design features and storage capacity, the dam plays a crucial role in water storage and flood control in the region, making it a significant asset for water resource and climate enthusiasts to study and monitor for sustainable management practices.
Dam Length |
823 |
River Or Stream |
INTERMITTENT |
Primary Dam Type |
Gravity |
Surface Area |
36.57 |
Hydraulic Height |
11 |
Drainage Area |
1.1 |
Nid Storage |
170.32 |
Structural Height |
16 |
Hazard Potential |
Low |
Foundations |
Unlisted/Unknown |
Nid Height |
16 |
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 |
|---|---|---|
Duck Creek - Lake Fort Peck
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West End - Lake Fort Peck
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The Pines - Fort Peck Lake
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Willow Creek Flat Dam (Valley)