Corps to close locks and dams for maintenanceView Source
The U.S. Army Corps of Engineers, St. Paul District, is closing some of its locks and dams in early December for maintenance. The closures will officially end the 2023 navigation season on the Mississippi River between Minneapolis and Guttenberg, Iowa.
Lock and dam 4 will close to all river traffic from December 4 to March 5, 2024, and Lock And Dam 7 will be closed from December 4 through March 15, 2024.
Lock and Dam 4, near Alma, will receive some updates. Maintenance is scheduled for the guidewall end cell, or circular structure at the end of the guidewall. Repairs include sheet pile and concrete placement.
Lock and Dam 7, near La Crescent, will be closed for guidewall maintenance. These repairs include divers inspecting the foundations, or cribs, anchored into the riverbed which the guidewalls sit upon. The divers will then install forms around the cribbing and pump grout into them to help fill voids in the foundations that were constructed in the 1930s.
Guidewalls are long extensions of a lock wall, both upstream and downstream of the lock chamber. They help guide tows during a lockage and provide mooring facilities for tows too long to be accommodated in a single lockage.
The St. Paul District navigation program provides a safe, reliable, cost-effective and environmentally sustainable waterborne transportation system on the Upper Mississippi River for the movement of commercial goods and for national security needs. To do this, the district maintains a nine-foot navigation channel and 13 locks and dams from Minneapolis to Guttenberg, Iowa. Keeping this system open is vital to the nation’s economy.