Thora #2 Reservoir Report
Nearby: Lyle Nelson #7 Game Reservoir
Last Updated: December 5, 2025
Thora #2, located in McCone County, Montana, is a privately owned dam designed by the USDA NRCS for fire protection, stock, and small fish pond purposes.
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Summary
Completed in 1946, this earthen dam stands at a height of 17 feet and has a storage capacity of 72 acre-feet. Situated on the North Fork Rock Creek, this structure plays a crucial role in enhancing water resource management in the area.
Managed by the DNRC and regulated by the state of Montana, Thora #2 is classified as a low hazard potential dam with a condition assessment of "Not Rated." Despite lacking recent inspection information, the dam's primary purpose remains vital for the surrounding community's safety and water resource utilization. With a maximum discharge capacity of 120 cubic feet per second, Thora #2 serves as a key asset for irrigation, livestock watering, and emergency firefighting efforts in the region.
As a significant feature within the Omaha District's water infrastructure, Thora #2 exemplifies the collaboration between federal and state agencies in ensuring efficient dam operations and compliance with regulatory standards. With its strategic location and multiple functions, this dam plays a crucial role in water supply management and environmental conservation efforts in Montana's diverse landscape.
Year Completed |
1946 |
Dam Length |
175 |
Dam Height |
17 |
River Or Stream |
NORTH FORK ROCK CREEK |
Primary Dam Type |
Earth |
Hydraulic Height |
17 |
Drainage Area |
0.56 |
Nid Storage |
72 |
Hazard Potential |
Low |
Nid Height |
17 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Nelson Creek Near Van Norman Mt
|
33cfs |
Milk River At Nashua Mt
|
233cfs |
Missouri River Near Wolf Point Mt
|
5020cfs |
Redwater River At Circle Mt
|
4cfs |
Milk River At Tampico Mt
|
123cfs |
Poplar River Near Poplar Mt
|
28cfs |
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.
Thora #2