Little Wall Reservoir Report
Nearby: Willow (Musselshell) Ivy
Last Updated: December 5, 2025
Little Wall is a private earth dam located in Musselshell, Montana, near the town of Mosby.
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Summary
Built in 1930, this dam serves multiple purposes including fire protection, stock, and as a small fish pond. It has a height of 20 feet and a storage capacity of 70 acre-feet, with a normal storage level of 37 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.
Situated on Little Wall Creek, this dam has a low hazard potential and is currently rated as "Not Rated" in terms of its condition assessment. Despite its age, the dam has not been modified over the years and does not have an Emergency Action Plan (EAP) in place. The surrounding area is relatively safe from potential flooding events, but there is no detailed risk assessment or management plan available for the dam. With its important role in providing water resources for the local community, Little Wall is a valuable asset that warrants ongoing monitoring and maintenance to ensure its continued safety and functionality for the future.
Year Completed |
1930 |
Dam Length |
300 |
Dam Height |
20 |
River Or Stream |
TR-LITTLE WALL CREEK |
Primary Dam Type |
Earth |
Hydraulic Height |
20 |
Nid Storage |
70 |
Hazard Potential |
Low |
Nid Height |
20 |
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.
Little Wall