Cain Reservoir Report
Nearby: Lavold Dam Lower Glasston Dam
Last Updated: December 5, 2025
Cain is a private irrigation dam located in Sweet Grass, Montana, along Tenmile Creek.
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Summary
Built in 1965 by the USDA NRCS, this earth dam stands at a height of 20 feet and has a storage capacity of 103 acre-feet. With a low hazard potential, Cain serves the primary purpose of irrigation for the surrounding area.
Managed by the DNRC, Cain is regulated and inspected by the state of Montana to ensure its structural integrity and safety. The dam has not been rated for its condition assessment, but it meets state permitting and inspection requirements. With a spillway width of 50 feet and a maximum discharge of 450 cubic feet per second, Cain is designed to manage water flow efficiently during peak periods.
Located in Greycliff, Montana, Cain plays a crucial role in water resource management for agricultural purposes in the region. As a key structure along Tenmile Creek, this dam demonstrates the importance of sustainable water infrastructure in supporting local communities and ecosystems in a changing climate.
Year Completed |
1965 |
Dam Length |
150 |
Dam Height |
20 |
River Or Stream |
TENMILE CREEK |
Primary Dam Type |
Earth |
Hydraulic Height |
20 |
Drainage Area |
0.63 |
Nid Storage |
103 |
Hazard Potential |
Low |
Nid Height |
20 |
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.
Cain