Mississippi River Lock And Dam 7 Reservoir Report

Last Updated: December 5, 2025

Mississippi River Lock and Dam 7, also known as Pool 7, is a federal-owned structure located in La Crescent, Minnesota.


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Summary

Completed in 1937, it serves primarily for navigation purposes along the Mississippi River. With a concrete dam type, Lock and Dam 7 has a hydraulic height of 25 feet and a structural height of 41 feet, providing a controlled spillway to maintain a constant pool level for river traffic at elevation 638.5.

The risk assessment for Lock and Dam 7 in 2018 identified it as a low-risk dam among over 700 dams managed by the US Army Corps of Engineers. Risks are primarily associated with aging miter gates in the locks and potential navigation accidents. To mitigate these risks, USACE continuously monitors and maintains the dam, prioritizing activities that reduce potential hazards. Additionally, public engagement and coordination with state and county emergency managers help raise awareness of dam-related risks and ensure public safety, particularly during river flood events.

Overall, Lock and Dam 7 plays a crucial role in maintaining navigational access along the Mississippi River, with USACE implementing risk management measures to safeguard public safety and reduce potential hazards associated with the dam. Despite identified risks, ongoing maintenance and proactive measures aim to ensure the continued functionality and safety of this important water resource infrastructure.

Year Completed

1937

Dam Length

10860

Dam Height

16

River Or Stream

MISSISSIPPI

Primary Dam Type

Concrete

Surface Area

13440

Length Of Locks

600

Hydraulic Height

25

Drainage Area

62340

Nid Storage

105000

Structural Height

41

Outlet Gates

Roller - 5, Tainter (radial) - 11, Uncontrolled - 0

Hazard Potential

Significant

Foundations

Soil

Nid Height

41
       
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.