Thorn Reservoir Report
Last Updated: December 6, 2025
Thorn is a privately owned irrigation dam located in Watkins, Montana, along the TR-Redwater River.
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Summary
Built in 1971, this Earth dam stands at a height of 10 feet and has a storage capacity of 92 acre-feet, primarily used for irrigation purposes. The dam has a low hazard potential and is regulated by the Montana Department of Natural Resources and Conservation (DNRC), with regular inspections and enforcement to ensure its safety and compliance with state regulations.
Situated in McCone County, Thorn serves as a vital water resource for the local agricultural community, providing essential irrigation water for crops in the region. With a normal storage capacity of 12 acre-feet, the dam plays a crucial role in sustaining the agricultural activities in the area. Despite being a privately owned structure, Thorn is subject to state jurisdiction, permitting, and inspection, highlighting the importance of water resource management and regulation in maintaining the sustainability of the local ecosystem.
Thorn's presence underscores the intersection of water resource management, climate resilience, and agricultural sustainability in Montana. As climate change continues to impact water availability and quality, structures like Thorn are essential for ensuring reliable water supply for agricultural operations. With its regulated status and low hazard potential, Thorn stands as a testament to responsible water infrastructure development and management, contributing to the resilience of the local community and ecosystem in the face of evolving climate challenges.
Year Completed |
1971 |
Dam Length |
250 |
Dam Height |
10 |
River Or Stream |
TR-REDWATER RIVER |
Primary Dam Type |
Earth |
Hydraulic Height |
10 |
Nid Storage |
92 |
Hazard Potential |
Low |
Nid Height |
10 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Redwater River At Circle Mt
|
1cfs |
Nelson Creek Near Van Norman Mt
|
33cfs |
Yellowstone River At Glendive Mt
|
6000cfs |
Yellowstone River At Miles City Mt
|
8100cfs |
Tongue River At Miles City Mt
|
263cfs |
Powder River Near Locate Mt
|
231cfs |
Dam Data Reference
Condition Assessment
SatisfactoryNo 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
HighDams 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.
Thorn