Olson Reservoir Report

Last Updated: December 5, 2025

Olson, Oscar (Meagher) is a private irrigation dam located in White Sulphur Springs, Montana, along the TR-South Fork Smith River.


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Summary

Constructed in 1959 by USDA NRCS, this Earth dam stands at a height of 39.5 feet and serves the primary purpose of irrigation. With a normal storage capacity of 256 acre-feet and a drainage area of 3300 acres, this dam plays a crucial role in managing water resources in the region.

The dam, owned and regulated by the DNRC, has a high hazard potential but is currently in satisfactory condition as per the latest assessment in December 2020. Equipped with a valve outlet gate and an uncontrolled spillway, it has a maximum storage capacity of 291 acre-feet and a surface area of 17.1 acres. Despite its moderate risk assessment, the dam meets regulatory guidelines and undergoes inspections every 5 years to ensure its continued safety and functionality.

Located in Congressional District 00, Montana, this dam is under the jurisdiction of the Omaha District of the USACE. With a history of effective risk management measures, including an Emergency Action Plan, and a dedicated team for inspections and enforcement, Olson, Oscar (Meagher) stands as a vital infrastructure for sustainable water resource management in the region.

Year Completed

1959

Dam Length

465

Dam Height

39.5

River Or Stream

TR-SOUTH FORK SMITH RIVER

Primary Dam Type

Earth

Surface Area

17.1

Hydraulic Height

37.4

Drainage Area

3300

Nid Storage

291

Outlet Gates

Valve

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

40
       
Seasonal Comparison

Weather Forecast

Dam Data Reference

Condition Assessment

Satisfactory
No 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

High
Dams 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.
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Area Campgrounds