Reservoir Lake Reservoir Report

Last Updated: December 5, 2025

Reservoir Lake in Montana, managed by the USDA Forest Service, is a picturesque Earth dam structure completed in 1920 for recreational purposes, with a storage capacity of 355 acre-feet.


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Summary

Situated in Beaverhead County near Dillon, the reservoir is fed by the Bloody Dick Creek and covers an area of 40 acres. The dam stands at 9 feet high and has a spillway width of 4 feet, with a low hazard potential and a moderate risk assessment rating.

This tranquil reservoir, nestled in the stunning Montana wilderness, offers opportunities for fishing, wildlife observation, and water-based recreation, attracting outdoor enthusiasts and nature lovers alike. With its uncontrolled outlet gates and a maximum discharge capacity of 218 cubic feet per second, Reservoir Lake provides a peaceful retreat in a remote setting. Despite its age, this dam remains in good condition, with a moderate risk rating, making it a safe and enjoyable destination for visitors seeking a serene escape in the heart of nature.

For water resource and climate enthusiasts, Reservoir Lake serves as both a recreational haven and a valuable water management asset. The Forest Service's oversight ensures the safety and maintenance of the dam, contributing to the sustainable use of water resources in the region. As a vital part of the local ecosystem and a scenic spot for outdoor activities, Reservoir Lake represents the harmonious coexistence of human recreation and natural preservation in the beautiful landscape of Montana.

Year Completed

1920

Dam Length

315

Dam Height

9

River Or Stream

BLOODY DICK CR

Primary Dam Type

Earth

Surface Area

40

Hydraulic Height

6

Drainage Area

1

Nid Storage

355

Structural Height

9

Outlet Gates

Uncontrolled

Hazard Potential

Low

Foundations

Unlisted/Unknown

Nid Height

9
       
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.