Mississippi River Lock And Dam 12 Reservoir Report
Nearby: Stamp Dam Big Mill Wetlands Dam
Last Updated: December 13, 2025
Mississippi River Lock and Dam 12, also known as Pool 12, is a federal structure located in Bellevue, Iowa, along the Mississippi River.
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Summary
Built in 1938 by the US Army Corps of Engineers, this concrete dam serves primarily for navigation purposes, with a length of 8,577 feet and a hydraulic height of 9 feet. It features a single lock with dimensions of 600 feet in length and 110 feet in width, facilitating the passage of vessels along the river.
With a significant hazard potential and a moderate risk assessment rating, the dam is managed by the US Army Corps of Engineers to address flood risk associated with the structure. Regular monitoring, maintenance, and engagement with local emergency managers are key components of the risk management measures implemented to ensure the dam's structural integrity and the safety of downstream communities. In the event of severe weather or increased water levels, the dam may release water to manage water levels and prevent potential issues.
As a critical infrastructure along the Mississippi River, Mississippi River Lock and Dam 12 plays a vital role in water resource management and climate adaptation efforts in the region. By employing proactive risk management strategies and continuously updating emergency action plans, the US Army Corps of Engineers ensures the safe operation of the dam and enhances preparedness for potential dam-related emergencies.
Year Completed |
1938 |
Dam Length |
8577 |
River Or Stream |
MISSISSIPPI RIVER |
Primary Dam Type |
Concrete |
Surface Area |
10500 |
Length Of Locks |
600 |
Hydraulic Height |
9 |
Drainage Area |
82400 |
Nid Storage |
92000 |
Structural Height |
44 |
Outlet Gates |
Roller - 3, Tainter (radial) - 7, Uncontrolled - 0 |
Hazard Potential |
Significant |
Foundations |
Soil |
Nid Height |
44 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Apple River Near Hanover
|
110cfs |
Sinsinawa River Near Menominee
|
19cfs |
Maquoketa River Near Maquoketa
|
569cfs |
North Fork Maquoketa River Near Fulton
|
245cfs |
Pecatonica River At Darlington
|
218cfs |
Platte River Near Rockville
|
85cfs |
Dam Data Reference
Condition Assessment
SatisfactoryNo 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
HighDams 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.
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