The U.S. Army Corps of Engineers Thursday confirmed eight locks and dams are expected to close April 18 and 19 due to high water levels from Iowa to Missouri.
A strong storm system carrying heavy rains swept across the U.S. Wednesday and Thursday, dumping plenty of precipitation into the Mississippi and on surrounding land.
According to the U.S. Geological Survey, nearly five inches of rain had fallen near Quincy in a 24-hour period. About 2-2.5 inches had fallen near Muscatine and Burlington.
Locks and dams 16-22 will be affected. Lock and dam 15 is also forecast to close, though not until April 21. The Army Corps has already closed three recreation areas at the Thomson Ranger Station, one at the Dubuque station, four at the Muscatine station, and six at the Quincy station.
As of Thursday afternoon, the river at Lock and Dam 22 was expected to crest at 26.8 feet on Sunday, well above the 16-foot flood level, while the river at Lock and Dam 16 was forecast to crest at 20.3 feet also on Sunday, five feet above the 15-foot flood stage.
Army Corps of Engineers for the Rock Island District note that navigation dams are constructed to maintain a 9-foot deep navigation channel for commercial transport, but the dams do not provide for flood control.
The Mississippi River maintains it flow through water draining into the river from 41% of the continental United States stretching from Montana to New York, and the Corps is required by law to maintain the channel within plus or minus one-half foot of the 9-foot target.
It is unknown when the locks and dams may reopen. According to 2012 data from the United Soybean Board, the average monthly value of corn and soybeans handled at each lock during the 2000–2010 period was $40.3 million for the Upper Mississippi River.