Wiggins #2 Reservoir Report
Nearby: Wiggins #3 Sharkey #1
Last Updated: December 5, 2025
Wiggins #2 is a privately owned irrigation dam located in Mosby, Montana, along the TR-Flatwillow Creek.
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Summary
Built in 1955 by USDA NRCS, this earthen dam stands at 12 feet high and spans 300 feet in length, with a storage capacity of 80 acre-feet. The dam is regulated by the Montana Department of Natural Resources Conservation (DNRC) and undergoes regular inspections, enforcement, and permitting to ensure its safety and compliance with state regulations.
With a low hazard potential and a condition assessment of "Not Rated," Wiggins #2 serves as a crucial water resource for agricultural irrigation in the area. The dam has a maximum discharge capacity of 500 cubic feet per second and a spillway width of 100 feet. While the dam has not been modified in recent years and lacks detailed risk assessment and emergency preparedness measures, its primary purpose of irrigation continues to support local farming operations in Petroleum County, Montana.
Overall, Wiggins #2 plays a vital role in sustaining water resources and climate resilience in the region, thanks to its efficient irrigation capabilities and state-regulated maintenance. As a key infrastructure project designed by USDA NRCS, this dam serves as a testament to the importance of proper water management and regulatory oversight in safeguarding critical water supplies for agricultural use in Montana.
Year Completed |
1955 |
Dam Length |
300 |
Dam Height |
12 |
River Or Stream |
TR-FLATWILLOW CREEK |
Primary Dam Type |
Earth |
Hydraulic Height |
12 |
Drainage Area |
10.47 |
Nid Storage |
80 |
Hazard Potential |
Low |
Nid Height |
12 |
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.
Wiggins #2