Thomas Reservoir Report
Nearby: Lindberg Petersen Dam
Last Updated: December 21, 2025
Thomas is a private earth dam located in the beautiful state of Montana, specifically in Sheridan County near the city of Antelope.
°F
°F
mph
Wind
%
Humidity
Summary
Built in 1939, this dam serves multiple purposes including fire protection, stock, and small fish pond management. It has a height of 12 feet and a length of 400 feet, providing a storage capacity of 232 acre-feet and a maximum discharge capability.
Managed by the Montana Department of Natural Resources and Conservation (DNRC), Thomas Dam is regulated and inspected by the state to ensure its safety and functionality. Despite being classified as having a low hazard potential, the dam's condition assessment is currently marked as 'Not Rated'. Surrounding areas can rest assured that this dam is continuously monitored and maintained to meet state regulatory standards and protect against potential risks.
Constructed in the Omaha District and falling under Congressional District 00 of Montana, Thomas Dam remains a vital water resource for the local community. Its location along the TR-Antelope Creek provides essential water for fire protection and agricultural activities, highlighting the importance of sustainable water management practices and the critical role that dams play in supporting various environmental and human needs in the region.
Year Completed |
1939 |
Dam Length |
400 |
Dam Height |
12 |
River Or Stream |
TR-ANTELOPE CREEK |
Primary Dam Type |
Earth |
Hydraulic Height |
12 |
Nid Storage |
232 |
Hazard Potential |
Low |
Nid Height |
12 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
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.
Thomas