Deveny Coulee Dam Reservoir Report
Nearby: Haines Reservoir Garverich #1
Last Updated: December 19, 2025
Deveny Coulee Dam, located in Forsyth, Montana, is a privately owned earth dam that was completed in 1950 by the USDA NRCS.
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Summary
The dam's primary purposes include fire protection, stock, and small fish pond. It stands at a height of 25 feet and has a length of 400 feet, with a maximum storage capacity of 23 acre-feet and a normal storage of 14 acre-feet. The dam is regulated by the Montana Department of Natural Resources and Conservation (DNRC) and is subject to state permitting, inspection, and enforcement.
The dam, situated on Deveny Coulee, serves as a vital water resource for the surrounding area, with a drainage area of 3.28 square miles and a maximum discharge capacity of 440 cubic feet per second. It features an uncontrolled spillway with a width of 60 feet and is classified as having a low hazard potential. While the dam's condition assessment is currently not rated, its risk assessment is moderate (3), indicating a need for ongoing monitoring and potential risk management measures. The dam is not owned or funded by any federal agencies, highlighting its status as a privately managed water infrastructure.
Deveny Coulee Dam plays a crucial role in supporting fire protection efforts, livestock watering, and small-scale fisheries in the region. With its moderate risk assessment and state oversight, the dam represents a key piece of infrastructure for managing water resources in Treasure County, Montana. Enthusiasts interested in water resource management and climate resilience can appreciate the significance of this privately owned dam in sustaining local ecosystems and communities.
Year Completed |
1950 |
Dam Length |
400 |
Dam Height |
25 |
River Or Stream |
DEVENY COULEE |
Primary Dam Type |
Earth |
Hydraulic Height |
25 |
Drainage Area |
3.28 |
Nid Storage |
23 |
Hazard Potential |
Low |
Nid Height |
25 |
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.
Deveny Coulee Dam