Holliday -Flagstaff Lake- Reservoir Report

Last Updated: December 5, 2025

Holliday -Flagstaff Lake- is a private irrigation dam located in Two Dot, Montana, on Flagstaff Creek.


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Summary

Built in 1939 by the USDA NRCS, this earth dam stands at 38 feet high and spans 800 feet in length. With a storage capacity of 250 acre-feet, the dam serves the primary purpose of irrigation for the surrounding area, providing water for agricultural activities. The structure is state-regulated by the Montana Department of Natural Resources and Conservation, ensuring proper inspection, enforcement, and permitting processes are in place to maintain its functionality.

Situated in Meagher County, Montana, Holliday -Flagstaff Lake- plays a crucial role in water resource management in the region, with a low hazard potential and a condition assessment of "Not Rated." The dam is designed to withstand hydraulic pressures and ensure the safety of downstream areas in case of emergencies. While the structure has not been modified in recent years, it continues to be a reliable resource for water supply and irrigation needs. The dam is not under the jurisdiction of the US Army Corps of Engineers, indicating that its operations and maintenance are overseen by private owners and state agencies.

As a key component of the irrigation infrastructure in the area, Holliday -Flagstaff Lake- contributes to the sustainable use of water resources and supports agricultural development in Meagher County. With a history dating back to the late 1930s, the dam stands as a testament to the importance of water management in arid regions like Montana. As climate change impacts water availability, structures like Holliday -Flagstaff Lake- become even more vital for securing water supplies and mitigating the effects of drought on agriculture and local communities.

Year Completed

1939

Dam Length

800

Dam Height

38

River Or Stream

FLAGSTAFF CREEK

Primary Dam Type

Earth

Hydraulic Height

34

Drainage Area

8.91

Nid Storage

250

Hazard Potential

Low

Nid Height

38
       
Seasonal Comparison

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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.