U.L.T. Detention Dam Reservoir Report
Nearby: Toprail Dam Whitetail Detention Dam
Last Updated: December 20, 2025
U.L.T.
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Summary
Detention Dam, located in Nashua, Montana, was completed in 1966 by the Bureau of Land Management for the primary purpose of flood risk reduction along the Willow Creek/Milk River. This gravity dam stands at a hydraulic height of 18 feet and has a length of 1350 feet, with a storage capacity of 432.3 acre-feet and a surface area of 71.6 acres. Despite its low hazard potential, the dam is in poor condition according to the last inspection in October 2017, and it has not been assessed for emergency action plans or risk management measures.
The U.L.T. Detention Dam, owned and managed by the Bureau of Land Management, serves as a critical infrastructure for flood control in Valley County, Montana. Despite lacking state permitting and inspection, the dam plays a crucial role in mitigating flood risks in the region. However, with a poor condition assessment and moderate risk level, there is a pressing need for improved maintenance and emergency preparedness to ensure the safety and functionality of the structure in the face of changing climate conditions.
Water resource and climate enthusiasts will find U.L.T. Detention Dam a fascinating example of federal efforts to manage flood risks in rural areas. The dam's location on the Willow Creek/Milk River and its design as a gravity structure with uncontrolled spillways highlight the challenges and importance of maintaining aging infrastructure for water resource management. As discussions around climate change and extreme weather events continue, the condition and resilience of dams like U.L.T. Detention Dam are crucial considerations for sustainable water management practices in the future.
Year Completed |
1966 |
Dam Length |
1350 |
River Or Stream |
WILLOW CK./MILK RIVER |
Primary Dam Type |
Gravity |
Surface Area |
71.6 |
Hydraulic Height |
18 |
Drainage Area |
12.6 |
Nid Storage |
432.3 |
Structural Height |
18 |
Hazard Potential |
Low |
Foundations |
Unlisted/Unknown |
Nid Height |
18 |
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.
U.L.T. Detention Dam