Long Horn #1 Dam Reservoir Report
Last Updated: December 20, 2025
Long Horn #1 Dam, located in Valley, Montana, is a gravity dam with a structural height of 26 feet and a hydraulic height of 21 feet.
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Summary
Managed by the Bureau of Land Management, this dam provides a storage capacity of 99.82 acre-feet, with a normal storage level of 34.09 acre-feet. With a surface area of 14.04 acres and a drainage area of 0.2 square miles, the dam serves as a crucial water resource in the region.
Although Long Horn #1 Dam has a low hazard potential, its condition assessment is deemed unsatisfactory, requiring attention and potential maintenance to ensure its structural integrity. The last inspection date was in September 2017, with a scheduled inspection frequency of every 5 years. Despite its moderate risk assessment level, the dam's emergency action plan (EAP) status, inundation maps, and risk management measures are currently unavailable, highlighting the importance of proactive monitoring and risk mitigation strategies for this essential water infrastructure.
For water resource and climate enthusiasts, Long Horn #1 Dam presents a fascinating case study of the intricate balance between water storage infrastructure and environmental sustainability. With its unique design features and historical significance, this dam serves as a reminder of the vital role that dams play in managing water resources and mitigating the impacts of climate change. As discussions around dam safety and maintenance continue to evolve, Long Horn #1 Dam stands as a testament to the ongoing challenges and opportunities in ensuring the resilience of our water infrastructure in the face of a changing climate.
Dam Length |
681 |
River Or Stream |
INTERMITTENT |
Primary Dam Type |
Gravity |
Surface Area |
14.04 |
Hydraulic Height |
21 |
Drainage Area |
0.2 |
Nid Storage |
99.82 |
Structural Height |
26 |
Hazard Potential |
Low |
Foundations |
Unlisted/Unknown |
Nid Height |
26 |
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.
Long Horn #1 Dam