Erickson #4 Reservoir Report
Nearby: Erickson #3 T L Johnson #1
Last Updated: December 8, 2025
Erickson #4 is a private earth dam located in Forsyth, Montana, along TR-Big Porcupine Creek.
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Summary
Built in 1931 by the USDA NRCS, this dam serves multiple purposes including fire protection, stock, and small fish pond management. With a dam height of 18 feet and a storage capacity of 108 acre-feet, Erickson #4 is designed to handle a maximum discharge of 600 cubic feet per second.
This dam has a low hazard potential and a moderate risk assessment rating. While the condition of the dam has not been officially assessed, the state regulatory agency DNRC oversees its inspection, permitting, and enforcement. The spillway of Erickson #4 is uncontrolled with a width of 75 feet, ensuring proper water flow during high precipitation events. Although the last inspection date and emergency preparedness details are not provided, the dam's risk management measures are not specified either.
Overall, Erickson #4 is a crucial water resource structure in Rosebud County, Montana, offering essential services for both fire protection and livestock management. With its historical significance dating back to the early 20th century, this dam continues to play a vital role in water conservation efforts in the region. As water resource and climate enthusiasts, monitoring and maintaining the integrity of Erickson #4 is essential to ensure its continued functionality and safety for the surrounding communities.
Year Completed |
1931 |
Dam Length |
225 |
Dam Height |
18 |
River Or Stream |
TR-BIG PORCUPINE CREEK |
Primary Dam Type |
Earth |
Hydraulic Height |
18 |
Drainage Area |
1.56 |
Nid Storage |
108 |
Hazard Potential |
Low |
Nid Height |
18 |
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.
Erickson #4