The U.S. Army Corps of Engineers says the Upper St. Anthony Falls Locks and Dams in Minneapolis got frequent use in the 2013 navigation seasons.
The Corps says the lock at the upper falls let boats pass 1,136 times, while there were 1,842 "lockages" at the lower falls, an overall increase from 2012. Those numbers include 581 passages involving commercial vessels through the upper falls and 1,365 through the lower falls.
The spread of invasive Asian carp up the river has led to calls for closing the locks and dams, which would take an act of Congress.
But the Corps says commercial tows carried more than 821,000 tons of commodities through the locks. It says close to 32,000 large semi trucks would have been needed to haul the same tonnage.