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Aerial image of Upper St. Anthony Falls Lock and Dam

Lock and Dam 4 winter maintenance update

U.S. Army Corps of Engineers, St. Paul District
Published Jan. 13, 2021

ST. PAUL, Minn. – The U.S. Army Corps of Engineers, St. Paul District, closed its parking lot and observation bridge at Lock and Dam 4, in Alma, Wisconsin, for winter maintenance after the end of last year’s navigation season.

Major winter maintenance like this occurs about every 20 years and includes concrete repairs, sandblasting and repainting the miter gates and updating the bubbler system used to prevent ice buildup within the lock chamber. Due to the use of heavy equipment and safety requirements, the parking lot and pedestrian bridge are closed during the repairs. The $3.5 million maintenance project is scheduled to be completed mid-March, ahead of the 2021 navigation season.

“We do this during the winter to ensure we don’t negatively impact navigation,” said Joe Schroetter, project manager. “While there are temporary impacts to viewing the Mighty Mississippi, the maintenance work ensures the lock will continue to deliver economic savings to agricultural producers and shippers across the Upper Midwest well into the future.”

While most of the work will be performed during the day, the facility is an active work site 24-hours a day, as sandblasting will be conducted overnight. There will be moderate industrial noise associated with this, mostly from the vacuum used to recover the sand. This construction method allows for the painters to follow during daylight hours and ensures the maintenance stays on schedule to reopen the lock on time.

The St. Paul District maintains 13 locks and dams from Minneapolis to Guttenberg, Iowa, and manages 243.6 miles of the Mississippi River 9-foot navigation channel. Keeping this system open is vital to the nation’s economy. The commercial navigation industry transported 10 million tons of commodities through Lock 4 during the 2020 navigation season. The industries making these shipments within the St. Paul District saved nearly $400 million by using the inland waterways instead of overland shipping methods.

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Release no. 21-002