Mississippi River Lock And Dam 11 Reservoir Report

Last Updated: December 5, 2025

Mississippi River Lock and Dam 11, also known as Pool 11, is a vital federal infrastructure located in Dubuque, Iowa.


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Summary

Completed in 1937, this concrete dam plays a crucial role in navigation along the Mississippi River, with a hydraulic height of 11 feet and a structural height of 43 feet. The dam's spillway type is controlled, with a spillway width of 1278 feet, and it features a single lock that is 600 feet long and 110 feet wide.

Despite being classified with a significant hazard potential, a risk assessment conducted by the US Army Corps of Engineers (USACE) in April 2019 deemed the risks associated with Lock and Dam 11 as normal. The assessment focused on potential issues such as a dam failure or a lock shutdown, with measures in place to mitigate these risks. Continuous inspections, maintenance activities, and an updated Emergency Action Plan contribute to the dam's well-maintained state and preparedness for any emergencies.

USACE is dedicated to reducing risks and ensuring the safety of the community surrounding Lock and Dam 11. With a focus on regular monitoring, updated emergency plans, and communication strategies, USACE works closely with state and local agencies to enhance emergency response capabilities and increase awareness among stakeholders and the public. This commitment to risk management and safety underscores the importance of Mississippi River Lock and Dam 11 in maintaining navigation and protecting the surrounding area from potential hazards.

Year Completed

1937

Dam Length

5130

River Or Stream

MISSISSIPPI RIVER

Primary Dam Type

Concrete

Surface Area

19613

Length Of Locks

600

Hydraulic Height

11

Drainage Area

81600

Nid Storage

170000

Structural Height

43

Outlet Gates

Roller - 3, Tainter (radial) - 13

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.