Mississippi River Lock and Dam 21, also known as Pool 21, is a federal-owned structure located in Hannibal, Missouri.
Wind
Humidity
Completed in 1938, 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 48 feet. The dam's purpose is primarily for navigation, and it features a single lock that is 600 feet long and 110 feet wide, allowing boats to pass through the river.
With a hazard potential deemed significant, the US Army Corps of Engineers (USACE) actively manages flood risks associated with the dam. Regular inspections, maintenance, and collaboration with local emergency managers are key components of the risk management measures in place. The dam has limited water storage capacity, and water releases may be necessary to manage water levels and ensure the dam's structural integrity. USACE works diligently to address all types of flood risk and maintain the safety and functionality of the Mississippi River Lock and Dam 21, serving as a critical infrastructure for water resource management and climate resilience in the region.
Year Completed |
1938 |
Dam Length |
3116 |
River Or Stream |
MISSISSIPPI RIVER |
Primary Dam Type |
Concrete |
Surface Area |
8843 |
Length Of Locks |
600 |
Hydraulic Height |
11 |
Drainage Area |
135000 |
Nid Storage |
62000 |
Structural Height |
48 |
Outlet Gates |
Roller - 3, Tainter (radial) - 10, Uncontrolled - 0 |
Hazard Potential |
Significant |
Foundations |
Soil |
Nid Height |
48 |
North River At Palmyra
|
15cfs |
South Fabius River Near Taylor
|
12cfs |
Bear Creek At Hannibal
|
2cfs |
Bear Creek Near Marcelline
|
5cfs |
Wyaconda River Above Canton
|
13cfs |
Salt River Near New London
|
82cfs |