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U.S. Army Corps of Engineers
St. Paul District
Programs & Project Management
180 5th St. E., Suite 700
St. Paul MN 55101

(651) 290-5755.


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Related Fact Sheet Information Paper

Posted 9/12/2016

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Updated September 2017

Lock and Dams 3-10 have a partially completed auxiliary chamber with a single set of miter gates that may be used to pass shallow draft navigation traffic in the event the lock chamber was out of operation and the upstream and downstream pools were equalized. The Auxiliary Miter Gates are considered emergency gates originally intended to allow for limited navigation if the main lock became inoperable. Only one set of miter gates were installed. Since installation, the auxiliary emergency gates have never been used and the gate operating machinery was never installed. The auxiliary lock chamber, to include a second set of miter gates, was never authorized or completed.

Recent Periodic Inspection Reports have raised concerns about the condition of the auxiliary miter gates at Locks 3 through 10 as they constitute a non-redundant portion of the damming surface that cannot be properly inspected and maintained. Deterioration and failure of the auxiliary miter gates could result in a loss of pool and disrupt navigation on the Upper Mississippi.

The double-walled sheet pile structure is planned to be installed upstream of the auxiliary gates. The auxiliary gates will remain in place. The sheet pile structure will act as a redundant damming service and a walkway. If removed, the sheetpile would not interfere with the function of the auxiliary gates and would allow passage of limited navigation at low flow to the same degree as would be possible under current conditions should the navigation lock be out of commission.


A contract was awarded in fiscal year 2016 for sheet pile installation at Lock and Dam 7, located in La Crosse, Wisconsin, at a cost of $3.1 Million.  Design for sheet pile installation at Locks and Dams 5, 5A, 9 and 10 is planned for fiscal year 2018.

Additional designs and construction will be completed based on availability of funding

The Upper Mississippi River 9-Foot Channel Navigation Project was authorized as part of the Rivers and Harbors Act approved July 3, 1930.


Auxiliary lock sheet pile installation design and construction are completed with 100 percent federal funds.

auxiliary locks Mississippi River locks navigation sheetpile closure St. Paul District U.S. Army Corps of Engineers