St. Paul Engineer District sets closure schedule for Upper Mississippi LocksView Source
The St. Paul Engineer District is closing four 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.
Locks and dams 2 and 4 will close to all river traffic December 4 – March 5, and locks and dams 3 and 7 will be closed December 4 – March 15. Lock and Dam 2, in Hastings, Minn., will be dewatered for concrete repairs.
Lock and Dam 3, near Welch, Minn., and Lock and Dam 7, near La Crescent, Minn., will be closed for guidewall maintenance. These repairs include divers inspecting the foundations, or cribs, anchored into the riverbed that 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.
Lock and Dam 4, near Alma, Wis., will also 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. 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 9-foot navigation channel and 13 locks and dams from Minneapolis to Guttenberg, Iowa.