Bn #11 Reservoir Report
Nearby: L Galt #24 L Galt #25
Last Updated: December 5, 2025
Bn #11 is a privately owned earth dam located in Mosby, Montana, along the TR-LIGHT COULEE river.
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Summary
Built in 1954, this dam serves multiple purposes including fire protection, stock watering, and creating a small fish pond. With a height of 14 feet and a length of 300 feet, it has a storage capacity of 105 acre-feet and a normal storage level of 51 acre-feet. The dam is regulated by the Montana Department of Natural Resources and Conservation (DNRC) and is inspected, permitted, and enforced by the state agency.
Despite being classified as having a low hazard potential, the condition of Bn #11 has not been officially rated. The dam has not undergone any modifications over the years, and no emergency action plan (EAP) or inundation maps have been prepared for the site. The dam is not under the jurisdiction of the U.S. Army Corps of Engineers and does not have any associated federal agency ownership, funding, or oversight. Overall, Bn #11 provides important water resource benefits to the local area while also serving as a potential recreational spot for fishing enthusiasts.
Year Completed |
1954 |
Dam Length |
300 |
Dam Height |
14 |
River Or Stream |
TR-LIGHT COULEE |
Primary Dam Type |
Earth |
Hydraulic Height |
14 |
Nid Storage |
105 |
Hazard Potential |
Low |
Nid Height |
14 |
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.
Bn #11