Pr-18 Retention Dam Reservoir Report

Last Updated: December 5, 2025

Pr-18 Retention Dam, located in Saco, Montana, was completed in 1942 by the Bureau of Land Management for fire protection, stock, and as a small fish pond.


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Summary

This gravity dam stands at a structural height of 30 feet and has a hydraulic height of 24 feet, providing a storage capacity of 85.85 acre-feet. Situated on Beaver Creek/Milk River, the dam plays a crucial role in managing water resources in the region.

Owned and funded by the Bureau of Land Management, this dam serves multiple purposes while also contributing to the local ecosystem. With a low hazard potential and a condition assessment of "Not Rated," the Pr-18 Retention Dam undergoes inspections every five years to ensure its safety and functionality. Despite its age, the dam continues to support the surrounding environment and communities by providing water for various needs.

As a significant landmark in Phillips County, Montana, the Pr-18 Retention Dam showcases the importance of sustainable water management practices. With its historical significance and critical role in water resource management, this dam stands as a testament to the ongoing efforts to balance human needs with environmental conservation in the face of changing climate conditions.

Year Completed

1942

Dam Length

300

River Or Stream

BEAVER CK./MILK RIVER

Primary Dam Type

Gravity

Surface Area

8.5

Hydraulic Height

24

Drainage Area

0.8

Nid Storage

85.85

Structural Height

30

Hazard Potential

Low

Foundations

Unlisted/Unknown

Nid Height

30
       
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.