Dyan Reservoir Report

Last Updated: December 5, 2025

Located in Chouteau, Montana, the Dyan dam is a state-regulated structure with a primary purpose of fire protection, stock, or small fish pond.


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Summary

Built in 1948, this earth dam stands at a height of 20 feet and has a storage capacity of 93 acre-feet. The dam is situated on the TR-SPRING COULEE river or stream, approximately 7 miles from the city of VIRGELLE.

Operated by the Montana Department of Natural Resources and Conservation (DNRC), Dyan has a low hazard potential and is currently rated as "Not Rated" in terms of condition assessment. The dam's emergency action plan (EAP) status and risk assessment details are currently not available, indicating a need for further information on the structure's safety and management measures. With its strategic location and key role in water resource management, Dyan serves as a vital asset for fire protection and livestock farming in the region.

Despite its age, Dyan continues to play a crucial role in water resource management in Montana, under the oversight of state regulators and inspection agencies. As an essential component of the local infrastructure, the dam's condition and safety standards are paramount to ensuring the protection of surrounding communities and ecosystems. With ongoing monitoring and potential risk assessment improvements, Dyan stands as a testament to the importance of sustainable water resource management in the face of changing climate conditions.

Year Completed

1948

Dam Length

600

Dam Height

20

River Or Stream

TR-SPRING COULEE

Primary Dam Type

Earth

Hydraulic Height

20

Nid Storage

93

Hazard Potential

Low

Nid Height

20
       
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.