Lock and Dam #6

Rojean Heyer, lock master for the U.S. Army Corps of Engineers at Lock and Dam No. 6 near Trempealeau, Wis., explains the scope of the work being done at the lock Thursday. The Corps along with contractor Kraemer North America is renovating and upgrading locks at three sites along the Upper Mississippi River this winter. (Brian Todd/btodd@postbulletin.com)

TREMPEALEAU, WIS. — Warm weather so far has been a boon to work being done at Lock and Dam No. 6 on the Upper Mississippi River. 

With work done on the lock being done in the winter – outside the barge navigation season – construction crews are hoping that trend continues as long as possible. Workers hope to complete the job by March. 

Scott Baker, a construction officers representative with the St. Paul District of the U.S. Army Corps of Engineers, said the work being done at the locks at Trempealeau mainly consists of upgrading the tow rail system that guides barges through the locks and replacing about 4-6 inches of concrete along the lock as part of an effort to improve safety at the site.

That includes new anchor spots along the tow rail system and bigger moorings.

"We want to make sure it's strong enough that when we have high flows, it can handle it," Baker said. 

The tow rail system helps move barges and tugs through the locks as they move up and down the river hauling commodities. The traveling mooring bitt systems, located on upper guide walls, promote efficient and safe passage for workers and long tows requiring multiple lockages, according to the Corps.

Lock and Dam #6

Workers conduct renovations at Lock and Dam No. 6 at Trempealeau, Wis., Thursday. The U.S. Army Corps of Engineers along with contractor Kraemer North America is renovating and upgrading locks at three sites along the Upper Mississippi River this winter. (Brian Todd/btodd@postbulletin.com)

The tow rail system being replaced was originally installed in 1961, Baker said. The $1.3 million upgrade and rehabilitation project is one of three happening this winter.

Locks and Dams Nos. 8 and 9 near Genoa and Eastman, Wis., respectively, are also seeing construction, though those projects are a bit more intensive with regard to concrete replacement, he said. 

Arne Thompson, a safety manager with Kraemer North America, the contractor on the project, said the cold weather can slow activities from welding to pouring cement, both vital parts of all the lock and dam projects.

For example, concrete and the pour site must be at 50 degrees when poured, and must be kept at 50 degrees for the first three days while setting. To keep the temperature of the concrete at 50 degrees, crews use a type of electric blanket over the material to keep it warm. 

While it has not been a problem during construction, Lock Master Rojean Heyer said the river is running higher than normal for this time of year. Other concerns are ice build-up during the winter, but the Corps uses a variety of methods to keep ice from building up in the locks. 

Baker said each lock and dam along the river is evaluated every five years for potential repairs. This year's project, while unique due to the tow rail replacement, is still just routine maintenance that must occur from time to time. 

Last year, 77 million tons of commodities were shipped downstream from the Port of St. Paul. A shortened navigation season, due mainly to late ice on the river then high flow levels, resulted in approximately a 30 percent drop in tonnage compared to the 2018 navigation season and about a 25 percent drop from the 10-year average.

The new tow rail systems should help ensure a safe navigation season in 2020. Corps Project Manager Kimberly Warshaw said improved safety is the No. 1 goal of the construction projects, which will install a uniform system along the Upper Mississippi lock and dam infrastructure. 

"We want to make sure the traveling mooring bitts work the same in all our systems," she said.

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