A new study suggests the failure of any one of 25 aging locks on the upper Mississippi River could result in nearly a half-million truckloads of freight on highways between the Twin Cities and St. Louis and would also impact Interstate 90 east of La Crosse.
University of Wisconsin-Madison researchers estimate that a shutdown of the river at Hannibal, Missouri, would require more than 12 million tons of grain during a nine-month shipping season to be moved by truck, costing hundreds of millions of dollars and damaging already stressed roads.
The vast majority of these shipments would travel through southern Minnesota and Iowa, while a smaller amount would move through Wisconsin and Illinois, according to the study, causing nearly $29 million in pavement damage.
The study was funded by the 10 states of the Mid-America Freight Coalition, an organization dedicated to planning, operating and improving transportation infrastructure in the Midwest.
“We’re talking about a system,” said Ernest Perry, manager of the coalition and the lead researcher on the study. “If we don’t take care of this one part of the system, it’s going to negatively impact another part of the system.”
The U.S. Army Corps of Engineers has estimated the backlogged maintenance costs for locks and dams of the Mississippi and Illinois rivers is more than $1 billion. Mostly built in the 1930s, many of the locks have reached the end of their service lives, and the inland waterway system has earned a D-minus from the American Society of Civil Engineers.
The lock and dams between Winona and La Crosse are more than 80 years old.
Bryan Peterson, navigation business line manager for the St. Paul District, said the Corps has been working in recent years to address maintenance issues as the budget allows.
“We definitely have needs,” he said. “I think we’re maintaining them well enough until we can fill those needs.”
Peterson said over the past five years, the river has been open about 99 percent of the time, with most closures resulting from vessels hitting the gates rather than mechanical failure.
“It’s always a potential,” he said. “It’s a pretty good record, but there’s always that risk.”
In the event of a river closure, the study estimates, about 1.4 million tons would originate from Winona and nearly 500,000 from La Crosse, which would result in more than 190 trucks per day traveling through Wisconsin on Interstate 90.
Nearly 5.8 million tons coming from the Twin Cities and Red Wing would result in nearly 600 more trucks per day on Highway 52 through southern Minnesota and into Iowa.
Researchers have previously assumed railroads would absorb most of the displaced shipments during a river shutdown. The study looked at scenarios in which trucking picks up 75 to 100 percent of the load. While it’s likely that more volume would move by rail, Perry said, states were interested in seeing the impact on roads.
One 15-barge tow carries the equivalent of about two trains or more than 1,000 trucks.
The study also focused only on agricultural products, though such products made up less than 30 percent of the total river volume in 2016, according to Corps data.
“There’s stuff moving north as well,” Perry noted.
Perry estimates the total costs of a season-long shutdown would be about $319.6 million, including the social costs of additional carbon dioxide emissions. The costs with failures in following years, he said, could begin to approach the $1 billion in deferred maintenance on the river.
“Everybody knows it’s an issue,” Perry said. “If we don’t take care of this one part of the system, it’s going to negatively impact another part of the system.”