Eva Murphy #4 Reservoir Report
Nearby: Graber #2 Eva Murphy #1
Last Updated: December 5, 2025
Eva Murphy #4 is a privately owned earth dam located in Mosby, Fergus County, Montana, along the TR-South Fork Bear Creek.
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Summary
Constructed in 1960 by the USDA NRCS, this dam stands at 20 feet high and spans 375 feet in length. With a primary purpose of providing fire protection, stock, and serving as a small fish pond, Eva Murphy #4 has a storage capacity of 117 acre-feet, with a normal storage level of 50 acre-feet.
This dam is regulated by the Montana Department of Natural Resources and Conservation (DNRC), with state permitting, inspection, and enforcement in place to ensure its safety and compliance. Despite being rated as having a low hazard potential, the risk assessment for Eva Murphy #4 indicates a moderate risk level (3). The spillway is uncontrolled, with a width of 10 feet, and the maximum discharge capability of the dam is 500 cubic feet per second.
Water resource and climate enthusiasts will find Eva Murphy #4 an intriguing structure due to its historical significance, multiple purposes, and regulatory oversight. With its location in a picturesque setting in Montana, this dam serves as a reminder of the importance of responsible water management and the need for ongoing monitoring and maintenance to ensure public safety and environmental protection.
Year Completed |
1960 |
Dam Length |
375 |
Dam Height |
20 |
River Or Stream |
TR-SOUTH FORK BEAR CREEK |
Primary Dam Type |
Earth |
Hydraulic Height |
20 |
Drainage Area |
1.56 |
Nid Storage |
117 |
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.
Eva Murphy #4