Judy Detention Dam Reservoir Report
Last Updated: December 19, 2025
Judy Detention Dam, located in Valley County, Montana, was completed in 1960 by the Bureau of Land Management for purposes including fire protection, stock, and small fish pond management.
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Summary
This gravity dam on Willow Creek, a tributary of the Milk River, stands at a structural height of 22 feet and has a hydraulic height of 17 feet. With a storage capacity of 803 acre-feet and a surface area of 65.05 acres, the dam serves as a crucial water resource for the surrounding area.
Managed by the Bureau of Land Management, Judy Detention Dam has a low hazard potential and a satisfactory condition assessment. It features an uncontrolled spillway with a width of 3 feet and is inspected every five years. Despite its moderate risk level, the dam has not had any major modifications since its construction and does not fall under the jurisdiction of state regulatory agencies. With its primary purpose of providing essential water resources for fire protection and livestock, Judy Detention Dam plays a vital role in sustaining the local ecosystem and supporting agricultural activities in the region.
Overall, Judy Detention Dam is a significant infrastructure asset in Valley County, Montana, ensuring water security for various uses while also contributing to the overall environmental health of the area. As a gravity dam with a long history of service, it continues to fulfill its intended purposes effectively, demonstrating the importance of proper water resource management in mitigating climate-related challenges and maintaining sustainable water supplies for the community.
Year Completed |
1960 |
Dam Length |
1037 |
River Or Stream |
WILLOW CK./MILK RIVER |
Primary Dam Type |
Gravity |
Surface Area |
65.05 |
Hydraulic Height |
17 |
Drainage Area |
0.1 |
Nid Storage |
803 |
Structural Height |
22 |
Hazard Potential |
Low |
Foundations |
Unlisted/Unknown |
Nid Height |
22 |
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.
Judy Detention Dam