Mahan And Hoyt Reservoir Reservoir Report
Nearby: Weson Little Brazil
Last Updated: December 19, 2025
Mahan and Hoyt Reservoir, also known as Wesen, is a private water resource located in Valley County, Montana, near the city of Glasgow.
°F
°F
mph
Wind
%
Humidity
Summary
This reservoir, completed in 1915, serves primarily for irrigation purposes, utilizing water from Brazil Creek. With a dam height of 8 feet and a storage capacity of 864 acre-feet, it plays a crucial role in supporting agricultural activities in the region.
Managed by the Montana Department of Natural Resources and Conservation (DNRC), Mahan and Hoyt Reservoir is state-regulated, inspected, and enforced to ensure its safety and functionality. Despite its low hazard potential, the reservoir has a moderate risk assessment rating, highlighting the importance of effective risk management measures. The spillway, with a width of 20 feet, is uncontrolled, emphasizing the need for careful monitoring and maintenance.
Water and climate enthusiasts interested in the sustainable use of water resources will find Mahan and Hoyt Reservoir an intriguing example of early 20th-century irrigation infrastructure in Montana. Its historical significance, combined with its operational efficiency and regulatory oversight, make it a valuable asset for both agricultural activities and environmental conservation efforts in the region.
Year Completed |
1915 |
Dam Length |
3195 |
Dam Height |
8 |
River Or Stream |
BRAZIL CREEK |
Primary Dam Type |
Earth |
Hydraulic Height |
5 |
Drainage Area |
3.32 |
Nid Storage |
864 |
Hazard Potential |
Low |
Nid Height |
8 |
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.
Mahan And Hoyt Reservoir