Seven Mississippi River locks between Muscatine, Iowa, and Saverton, Mo., were expected to close beginning on Friday as the rain-swollen waterway rises above flood stage, the U.S. Army Corps of Engineers said on Thursday.
The closures of Locks 16 through 22 will effectively shut the river to commercial navigation from central Iowa to northern Missouri.
The river was forecast to crest on Sunday at Lock 16 in Muscatine at a river gauge reading of 21.3 feet, more than 5 feet above flood stage and 4.3 feet below the record crest, according to the latest National Weather Service river forecast.
At Lock and Dam 22 in Saverton, the river was forecast to crest at 26.3 feet on Tuesday, more than 10 feet above flood stage and 3.3 feet short of its record crest at that location.
"Based on current forecasts, we're looking at most of them closing on Friday," said Rob Germann, operations manager for the Army Corps' Mississippi River project, Rock Island district.
"Depending on how the rain continues this week will determine how that crest drains out," he said.
Some 60 percent of U.S. grain exports are shipped via the Mississippi River and its tributaries from farms in the Midwest to export terminals at the Gulf of Mexico.