Foss Reservoir Report
Last Updated: December 13, 2025
Located in Blair, Montana, Foss is a privately owned earth dam designed by the USDA NRCS for irrigation purposes on the South Charlie Creek.
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Summary
Built in 1964, this structure stands at 16 feet high with a storage capacity of 59 acre-feet. With a low hazard potential and a moderate risk assessment rating, Foss plays a crucial role in managing water resources in the region.
Operated under state jurisdiction by the DNRC, Foss is regulated, inspected, and enforced to ensure its safety and functionality. The dam has a spillway width of 300 feet and can discharge up to 3000 cubic feet per second. Despite not being rated for its condition, Foss continues to serve its primary purpose of irrigation with a normal storage capacity of 42 acre-feet.
With its strategic location and design, Foss contributes to the sustainable management of water resources in Richland County, Montana. As a key infrastructure for irrigation, this dam highlights the importance of effective water resource management in the face of changing climate conditions.
Year Completed |
1964 |
Dam Length |
465 |
Dam Height |
16 |
River Or Stream |
SOUTH CHARLIE CREEK |
Primary Dam Type |
Earth |
Hydraulic Height |
14 |
Drainage Area |
0.34 |
Nid Storage |
59 |
Hazard Potential |
Low |
Nid Height |
16 |
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.
Foss