Mississippi River Locks And Dam 1 Reservoir Report

Last Updated: December 5, 2025

Mississippi River Locks and Dam 1, also known as Pool 1, is a vital piece of infrastructure located in St.


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Summary

Paul, Minnesota. Constructed in 1917 by the US Army Corps of Engineers, this concrete dam stands at a height of 49 feet and serves primarily for navigation purposes on the Mississippi River. With a hydraulic height of 56 feet and a structural height of 51 feet, the dam provides essential control over the river's water levels, with a spillway width of 574 feet and a maximum discharge of 742 cubic feet per second.

This significant dam, with a storage capacity of 9,300 acre-feet, covers a surface area of 900 acres and serves a drainage area of 19,500 square miles. With two locks each measuring 400 feet in length and 56 feet in width, Mississippi River Locks and Dam 1 plays a crucial role in managing water flow, preventing floods, and supporting recreational activities in the region. Regular maintenance and risk management measures are implemented by the US Army Corps of Engineers to ensure the dam's structural integrity and readiness to respond to any potential emergencies, highlighting the importance of this key water resource infrastructure.

As part of a larger system of dams along the Mississippi River, Mississippi River Locks and Dam 1 faces various risks associated with flood management and severe weather events. The US Army Corps of Engineers actively monitors the dam's condition, engages with local emergency managers, and updates emergency action plans to enhance preparedness and response capabilities. By working collaboratively with stakeholders and implementing ongoing maintenance and risk mitigation strategies, this dam continues to play a critical role in supporting water resource management and climate resilience efforts in the region.

Year Completed

1917

Dam Length

742

Dam Height

49

River Or Stream

MISSISSIPPI

Primary Dam Type

Concrete

Surface Area

900

Length Of Locks

400

Hydraulic Height

56

Drainage Area

19500

Nid Storage

9300

Structural Height

51

Outlet Gates

Uncontrolled - 0

Hazard Potential

Significant

Foundations

Rock, Soil

Nid Height

56
       
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.