Hanson Co #11 Reservoir Report
Nearby: Stellar Lake Hanson Co #12
Last Updated: December 6, 2025
Hanson CO #11 is a privately-owned irrigation dam located in Rosebud County, Montana, along the TR-Little Porcupine Creek.
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Summary
Built in 1962 by the USDA NRCS, this earth dam stands at 15 feet high and has a storage capacity of 135 acre-feet, serving the primary purpose of irrigation. With a low hazard potential and a condition assessment of "Not Rated," this dam plays a crucial role in supporting agricultural activities in the region.
Managed by the DNRC and falling under state jurisdiction, Hanson CO #11 undergoes regular state inspections, permitting, and enforcement to ensure its safety and compliance with regulations. Located in a picturesque setting in Cartersville, Montana, this dam is essential for maintaining water resources in the area and supporting the local ecosystem. With a maximum discharge capacity of 800 cubic feet per second and a spillway width of 100 feet, this dam is equipped to handle varying water flow conditions effectively.
Despite its importance for irrigation and water management, Hanson CO #11 has not been rated for its condition and lacks detailed information on emergency action plans and risk assessments. However, with its long history of service and the oversight of the NRCS and state regulatory agencies, this dam continues to be a vital infrastructure for water resource management in Rosebud County.
Year Completed |
1962 |
Dam Length |
275 |
Dam Height |
15 |
River Or Stream |
TR-LITTLE PORCUPINE CREEK |
Primary Dam Type |
Earth |
Hydraulic Height |
15 |
Drainage Area |
1.41 |
Nid Storage |
135 |
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 #11