St. Anthony Falls Lower Lock And Dam Reservoir Report

Last Updated: December 5, 2025

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Summary

Anthony Falls Lower Lock and Dam, located in Minneapolis, Minnesota, is a vital structure on the Mississippi River, serving primarily for navigation purposes. Completed in 1956, this concrete dam stands at a height of 41 feet with a hydraulic height of 39 feet and a structural height of 58 feet. The dam's length spans 213 feet and includes a single lock measuring 400 feet in length and 56 feet in width. Managed by the US Army Corps of Engineers, the dam has a significant hazard potential and a very high risk assessment rating, emphasizing the importance of ongoing monitoring and risk management measures.

The dam's purpose extends beyond navigation to include recreation, making it a key resource for water enthusiasts in the area. With a storage capacity of 420 acre-feet and a maximum discharge rate of 91,000 cubic feet per second, the dam plays a crucial role in managing water levels and preventing flooding in the region. The USACE works diligently to address various flood risks associated with the dam, regularly updating emergency action plans, conducting maintenance and repairs, and collaborating with local emergency managers to raise awareness and support preparedness efforts. As climate change continues to impact water resources, the St. Anthony Falls Lower Lock and Dam remains a critical infrastructure for both navigation and flood control on the Mississippi River.

Year Completed

1956

Dam Length

213

Dam Height

41

River Or Stream

MISSISSIPPI

Primary Dam Type

Concrete

Surface Area

50

Length Of Locks

400

Hydraulic Height

39

Drainage Area

19680

Nid Storage

420

Structural Height

58

Outlet Gates

Tainter (radial) - 3, Uncontrolled - 0

Hazard Potential

Significant

Foundations

Rock

Nid Height

58
       
Seasonal Comparison

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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.