Nelson (Phillips) Reservoir Report
Last Updated: December 5, 2025
Nelson (Phillips) is a private irrigation dam located in Saco, Montana, within Phillips County.
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Summary
Built in 1920 by the USDA NRCS, this earth dam stands at 27 feet high and spans 390 feet in length. With a storage capacity of 4,170 acre-feet and a normal storage of 1,236 acre-feet, the dam serves the primary purpose of irrigation along TR-BEAVER CREEK.
Despite being classified as having a low hazard potential and not yet rated for its condition assessment, Nelson (Phillips) is regulated by the Montana Department of Natural Resources and Conservation, with state permitting, inspection, and enforcement in place. The dam's spillway boasts a width of 54 feet and a maximum discharge of 270 cubic feet per second. Additionally, located in Congressional District 00, the dam is under the representation of Congressman Greg Gianforte.
Water resource and climate enthusiasts will find Nelson (Phillips) to be a fascinating example of early 20th-century irrigation infrastructure in Montana. With its historical significance and ongoing state regulation, this dam serves as a reminder of the importance of sustainable water management practices in the region. As efforts are made to assess and potentially improve its condition, Nelson (Phillips) stands as a testament to the intersection of human ingenuity and environmental stewardship in the face of changing climates and water resource challenges.
Year Completed |
1920 |
Dam Length |
390 |
Dam Height |
27 |
River Or Stream |
TR-BEAVER CREEK |
Primary Dam Type |
Earth |
Surface Area |
114 |
Hydraulic Height |
25 |
Drainage Area |
6.25 |
Nid Storage |
4170 |
Hazard Potential |
Low |
Nid Height |
27 |
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.
Nelson (Phillips)