Guidewalls are long extensions of the lock walls, in either the upstream or downstream direction, that are parallel to the lock wall. At each of the Mississippi River Locks and Dams 2 through 10, guidewalls serve primarily to guide the long tows into the lock and to provide mooring facilities for tows too long to be accommodated in a single lockage.
The guidewalls are constructed of multiple 35 to 40 foot length concrete monoliths with rock filled timber cribs beneath them. Guidewalls have been shifted and damaged over time, leading to serviceability and safety issues.
The U.S. Army Corps of Engineers’ Lock and Dam 2 through 10 Lock Guidewall Distress Repair Project has been ongoing since the mid-1990s. This project will fill the timber cribs beneath the concrete monoliths with a cementitious fill, improving stability and safety. To place the fill, construction crews place a floating silt curtain, form work and grouting along the riverward face of the crib during the non-navigation season.
Construction was completed in March of 2016 at Lock and Dam 7. Construction was completed at Locks and Dams 6 and 8 in March 2018. Locks and Dams 4, 5, 5A and 9 construction were completed during the 2018‒2019 winter non-navigation season.
Additional projects will be scheduled when funding is made available and will be based upon the recommendations in the Guidewall Distress Repair Report.
Congress authorized the Upper Mississippi River 9-Foot Channel Navigation Project as part of the Rivers and Harbors Act approved July 3, 1930.
Guidewall crib repair design and construction at the locks and dams are accomplished with 100 percent federal funds. Total work is estimated at $30 million.
Fiscal year 2016:
Construction at Lock and Dam 7 $1,200,000
Fiscal year 2018:
Construction at Locks and Dams 5, 6, 8, 9 $9,500,000
Construction at Locks and Dams 4 and 5A $5,380,000