Soo Locks Reservoir Report

Last Updated: December 5, 2025

The Soo Locks, located in Sault Ste Marie, Michigan, are a critical part of the Great Lakes navigation system.


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Summary

Built in 1921, the complex consists of four locks that help ships navigate the St. Mary's River. The locks play a crucial role in facilitating the transportation of goods and resources between Lake Superior and the lower Great Lakes.

Despite their age, the Soo Locks are well-maintained by the US Army Corps of Engineers, who work diligently to address any potential risks and ensure the continuous operation of the locks. A recent risk assessment classified the complex as having a high risk due to aging infrastructure, which could lead to interruptions in navigation and power generation. To mitigate these risks, the USACE has implemented various measures, including routine monitoring, surveillance, and construction projects to address vulnerable features.

One of the key initiatives currently underway is the construction of a new, high-capacity lock to replace two decommissioned locks. This new lock will provide essential redundancy and ensure continuous operation, even in the event of closures or failures in the existing infrastructure. With these proactive measures in place, the Soo Locks continue to play a vital role in supporting water resource management and climate resilience in the region.

Year Completed

1921

Dam Length

968

River Or Stream

ST MARY S

Primary Dam Type

Concrete

Surface Area

20255000

Length Of Locks

1200

Hydraulic Height

14

Drainage Area

181000

Nid Storage

277540000

Structural Height

17

Outlet Gates

Tainter (radial) - 16

Hazard Potential

High

Foundations

Rock

Nid Height

17
       
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.