Rick Calhoun says the drought that halted barge traffic on the Mississippi River last year would look like a comparatively minor problem if one of the nation's aging locks and dams were to fail.
The lock and dam system, mostly built in the 1930s, has long outlived its life expectancy, according to the Cargill executive, and requires new investment by the federal government.
"It's our fear that at some point in time we could have a failure, and actually shut down a lock or a dam for an extended period of time, doing severe economic harm," said Calhoun, marine and terminal division president for Cargill, the Minnetonka-based agribusiness giant.
He has been speaking publicly on the state of the nation's waterways in recent weeks, including at a U.S. Department of Agriculture conference in Washington last week.
Snowstorms have strafed the Midwest and river levels have risen in recent weeks, easing concerns that the 2013 shipping season will be a repeat of last year's, with low river levels interfering with shipping on the Mississippi. But worries over the condition of the lock and dam system are lingering, with no end in sight.
"The infrastructure is in dire straits," said Lee Nelson, president of Upper River Services Inc. in St. Paul, which moves barges between terminals on the river.
A 280-foot section of wall at the Lockport Canal near Chicago collapsed and slid into the Illinois Waterway in 2011.
In 2009, a lock gate fell off its hinges in Ohio and took five months to repair. Fortunately for Ohio River shippers, that lock had an auxiliary chamber to allow barge traffic to continue during repairs. But on the Upper Mississippi, "less than a handful" of the 27 locks have auxiliary chambers.