Hanson Co #12 Reservoir Report
Nearby: Hanson Co #11 Stellar Lake
Last Updated: December 6, 2025
Hanson CO #12 is a private irrigation dam located in Rosebud County, Montana, specifically in the city of Cartersville.
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Summary
Built in 1954 by the USDA NRCS, this earth dam stands at a height of 15 feet and has a maximum storage capacity of 84 acre-feet. Serving the primary purpose of irrigation, the dam is situated on TR-Little Porcupine Creek and covers a drainage area of 0.31 square miles.
Managed by the DNRC, Hanson CO #12 has a low hazard potential and has not been rated for its current condition. With a spillway width of 100 feet and a maximum discharge capacity of 700 cubic feet per second, this dam plays a crucial role in water resource management in the area. While it has not undergone recent inspections or assessments, the dam meets state regulatory standards and is subject to state permitting, inspection, and enforcement.
Located within Congressional District 00 of Montana, Hanson CO #12 is a key structure for agricultural water supply in the region. As water resource and climate enthusiasts, understanding the importance of maintaining and monitoring dams like Hanson CO #12 is vital for ensuring sustainable water management practices and mitigating potential risks associated with irrigation infrastructure.
Year Completed |
1954 |
Dam Length |
125 |
Dam Height |
15 |
River Or Stream |
TR-LITTLE PORCUPINE CREEK |
Primary Dam Type |
Earth |
Hydraulic Height |
15 |
Drainage Area |
0.31 |
Nid Storage |
84 |
Hazard Potential |
Low |
Nid Height |
15 |
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.
Hanson Co #12