Rosann Rosanna Dana Reservoir Report

Last Updated: December 5, 2025

Rosann Rosanna Dana is a privately-owned dam located in Sweet Grass, Montana, along TR-Countryman Creek.


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Summary

Built in 1939, this Earth-type dam stands at a height of 50 feet and has a storage capacity of 107 acre-feet. Despite its age, the dam is in overall good condition, with a low hazard potential and a lack of recent assessment.

Managed by the Montana Department of Natural Resources and Conservation (DNRC), Rosann Rosanna Dana plays a crucial role in regulating water flow and providing water resources for the surrounding area. With a primary purpose of "Other," this dam serves a unique function that contributes to the overall water management system in the region. While it may not have associated structures or a defined spillway type, the dam continues to fulfill its role effectively.

Situated in a picturesque location near Columbus, Montana, Rosann Rosanna Dana stands as a testament to the importance of water resource infrastructure in the face of changing climate conditions. As water resource and climate enthusiasts, the unique characteristics and historical significance of this dam make it a fascinating case study for understanding the intersection of water management, engineering, and environmental stewardship.

Year Completed

1939

Dam Length

200

Dam Height

50

River Or Stream

TR-COUNTRYMAN CREEK

Primary Dam Type

Earth

Hydraulic Height

50

Nid Storage

107

Hazard Potential

Low

Nid Height

50
       
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.