Sandy Lock And Dam Reservoir Report

Last Updated: December 5, 2025

Sandy Lock and Dam, located in Libby, Minnesota, is a crucial federal structure managed by the US Army Corps of Engineers.


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Summary

Built in 1895 on the Sandy River, this Earth-type dam serves multiple purposes such as flood risk reduction, navigation, and water supply. With a height of 14 feet and a length of 109 feet, the dam holds a normal storage capacity of 38,000 acre-feet in the Sandy Lake Reservoir.

Despite being classified as a low hazard potential structure, Sandy Lock and Dam is subject to various flood risks that the USACE actively manages. By continuously monitoring the dam's condition, prioritizing risk-reducing activities, and collaborating with local emergency managers, the USACE ensures the safety and functionality of the structure. Additionally, the USACE regularly updates the emergency action plan and conducts maintenance to mitigate potential issues and maintain the dam's structural integrity.

As water resource and climate enthusiasts, understanding the risk management measures employed at Sandy Lock and Dam provides valuable insight into the complexities of maintaining and safeguarding critical infrastructure. By staying informed about the dam's operations and potential risks, enthusiasts can contribute to efforts aimed at protecting communities and ecosystems in the face of changing climatic conditions and severe weather events.

Year Completed

1895

Dam Length

109

Dam Height

14

River Or Stream

SANDY RIVER

Primary Dam Type

Earth

Surface Area

9400

Length Of Locks

160

Hydraulic Height

13

Drainage Area

421

Nid Storage

79400

Structural Height

22

Outlet Gates

Other Controlled - 6, Slide (sluice gate) - 6

Hazard Potential

Low

Foundations

Soil

Nid Height

22
       
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.