Drga Dam Reservoir Report

Last Updated: December 5, 2025

Drga Dam, also known as Big Dam or Comet, is a private-owned structure located in Iliad, Montana, along the Sage Coulee river.


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Summary

Completed in 1938, this earth-type dam stands at a height of 30 feet and has a length of 400 feet, providing fire protection, stock, and serving as a small fish pond. With a storage capacity of 148 acre-feet, the dam's primary purpose is to benefit the local community by safeguarding against wildfires and supporting agricultural activities.

The significant hazard potential of Drga Dam underscores the importance of regular inspections and maintenance to ensure its structural integrity and safety. Despite being last inspected in 1995, the dam's condition remains unrated, highlighting the need for updated assessments and emergency preparedness measures. The regulatory oversight by the Montana Department of Natural Resources and Conservation (DNRC) underscores the importance of adherence to state regulations and enforcement to mitigate risks and protect the surrounding environment and communities.

Located in Chouteau County, Montana, Drga Dam serves as a vital water resource for the region, with a normal storage capacity of 110 acre-feet and a surface area of 12.8 acres. As climate change impacts water availability and quality, the management and maintenance of structures like Drga Dam become increasingly crucial in ensuring sustainable water usage and resilience to changing environmental conditions. Enthusiasts of water resources and climate resilience can appreciate the significance of Drga Dam in supporting local ecosystems and the community's water needs.

Year Completed

1938

Dam Length

400

Dam Height

30

River Or Stream

SAGE COULEE

Primary Dam Type

Earth

Surface Area

12.8

Hydraulic Height

26

Nid Storage

148

Hazard Potential

Significant

Nid Height

30
       
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.