Hainie Reservoir Reservoir Report

Last Updated: December 19, 2025

Hainie Reservoir in Montana, managed by the USDA NRCS, was completed in 1942 and serves multiple purposes including fire protection, stock watering, and small fish pond.


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Summary

With a dam height of 19 feet and a storage capacity of 88 acre-feet, this earth dam on Lost Creek provides crucial water resources for the surrounding area. The reservoir has a low hazard potential and a moderate risk assessment rating.

Located in McCone County near the city of Poplar, Hainie Reservoir is regulated by the Montana Department of Natural Resources and Conservation (DNRC). The reservoir has a spillway width of 50 feet and a maximum discharge capacity of 500 cubic feet per second. Despite not being rated for its condition, the reservoir is inspected, permitted, and enforced by state agencies to ensure its safety and functionality for water resource management and climate resilience in the region.

For water resource and climate enthusiasts, Hainie Reservoir offers a fascinating study in sustainable water management practices and the importance of small-scale reservoirs in supporting local agriculture, wildlife, and emergency preparedness. With its historic significance, diverse uses, and state-regulated operation, Hainie Reservoir stands as a testament to the vital role of water infrastructure in maintaining ecological balance and community resilience in Montana.

Year Completed

1942

Dam Length

1122

Dam Height

19

River Or Stream

LOST CREEK

Primary Dam Type

Earth

Hydraulic Height

19

Drainage Area

3.13

Nid Storage

88

Hazard Potential

Low

Nid Height

19
       
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.