Lebo #3 Reservoir Report

Last Updated: December 5, 2025

Lebo #3, East Dam, also known as Lebo Lake, is a privately owned structure located in Shawmut, Montana.


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Summary

Built in 1973 by the USDA NRCS, this Earth-type dam serves primarily for irrigation purposes along the TR-Lebo Creek. With a height of 27 feet and a storage capacity of 4,735 acre-feet, the dam covers a surface area of 413 acres and has a drainage area of 2.7 square miles.

The dam has a spillway width of 35 feet and an uncontrolled spillway type, with a maximum discharge capacity of 110 cubic feet per second. Despite being classified as having a high hazard potential, the condition assessment as of December 2020 was deemed satisfactory. The emergency action plan for the dam was last revised in September 2020, and the risk assessment indicates a moderate risk level.

For water resource and climate enthusiasts, Lebo #3, East Dam offers an intriguing case study in dam infrastructure management and risk mitigation. Its location in the Wheatland County of Montana, under the jurisdiction of the DNRC, presents unique challenges and opportunities for sustainable water resource utilization. With a rich history of irrigation support dating back to its construction in the 1970s, the dam continues to play a crucial role in the local agricultural landscape.

Year Completed

1973

Dam Length

388

Dam Height

27

River Or Stream

TR-LEBO CREEK

Primary Dam Type

Earth

Surface Area

413

Hydraulic Height

27

Drainage Area

2.7

Nid Storage

4735

Outlet Gates

Slide (sluice gate)

Hazard Potential

High

Foundations

Rock

Nid Height

27
       
Seasonal Comparison

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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.