Mississippi River Lock And Dam 5 Reservoir Report

Last Updated: December 5, 2025

Mississippi River Lock and Dam 5, also known as Pool 5, is a vital structure located in Minnesota, specifically in Winona County.


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Summary

Built in 1935 by the US Army Corps of Engineers, this concrete dam stands at 22 feet high and serves primarily for navigation purposes along the Mississippi River. With a controlled spillway width of 1340 feet, the dam helps maintain a constant pool level for river traffic, even during peak flows of up to 270,000 cubic feet per second. The dam features a single lock measuring 600 feet in length and 110 feet in width, facilitating the passage of vessels through the river.

Although Lock and Dam 5 is considered a moderate-risk dam by the USACE, steps are continuously being taken to reduce potential hazards. Regular inspections, maintenance, and repairs are carried out to ensure the dam's structural integrity and functionality. Identified risks include overtopping of the embankment, deteriorated auxiliary lock gates, and potential deterioration of low-flow conduits. To manage flood risks and ensure public safety, USACE collaborates with state and county emergency managers, conducts public awareness campaigns, and enforces safety measures for swimming and boating in the dam's vicinity. Overall, Lock and Dam 5 plays a crucial role in supporting navigation and recreation along the Mississippi River while maintaining public safety and minimizing potential risks.

Year Completed

1935

Dam Length

19600

Dam Height

22

River Or Stream

MISSISSIPPI

Primary Dam Type

Concrete

Surface Area

12580

Length Of Locks

600

Hydraulic Height

26

Drainage Area

58845

Nid Storage

106600

Structural Height

43

Outlet Gates

Roller - 6, Tainter (radial) - 28

Hazard Potential

Significant

Foundations

Soil

Nid Height

43
       
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.