Beardsley Retention Dam Reservoir Report

Last Updated: December 5, 2025

The Beardsley Retention Dam, located in Terry, Montana, serves multiple purposes including fire protection, stock containment, and creating a small fish pond.


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Summary

Managed by the Bureau of Land Management, this gravity dam stands at a structural height of 31 feet and has a hydraulic height of 21 feet. Completed in 2003, the dam has a storage capacity of 121.4 acre-feet and covers a surface area of 20.4 acres, with a drainage area of 2.4 square miles.

With a low hazard potential and poor condition assessment, the Beardsley Retention Dam poses a moderate risk according to the data. The dam features an uncontrolled spillway with a width of 4 feet, and has a history of inspections with a frequency of every 5 years. While the dam has not been modified in recent years, it is important for water resource and climate enthusiasts to monitor its condition and risk management measures moving forward to ensure the safety and integrity of this vital infrastructure in the region.

Overall, the Beardsley Retention Dam stands as a crucial structure for water resource management in Custer County, Montana. As part of the efforts to protect against fires, contain stock, and provide recreational opportunities, the dam plays a significant role in the local ecosystem. With ongoing monitoring and maintenance, the dam will continue to support the community while mitigating potential risks associated with its operation.

Year Completed

2003

Dam Length

878

River Or Stream

COAL CK./POWDER RIVER

Primary Dam Type

Gravity

Surface Area

20.4

Hydraulic Height

21

Drainage Area

2.4

Nid Storage

121.4

Structural Height

31

Hazard Potential

Low

Foundations

Unlisted/Unknown

Nid Height

31
       
Seasonal Comparison

Weather Forecast

Dam Data Reference

Condition Assessment

Satisfactory
No 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

High
Dams 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.