Floods shut Mississippi, Illinois river locks: Army Corps Fri Apr 19, 2013 6:02pm EDT (Reuters) - Barge shipping was halted on Friday on parts of the Illinois and Mississippi rivers as flooding forced the closure of several locks until at least the middle of next week, the U.S. Army Corps of Engineers said. The closures come three months after near-record-low water along the Mississippi River near St. Louis threatened to halt commercial barge traffic. Some 60 percent of U.S. grain export shipments are moved on barges on the Mississippi and its tributaries from production centers in the Midwest to export terminals at the Gulf of Mexico. Torrential rains this week flooded broad swaths of Illinois and neighboring states, slowing farmer deliveries of grain to elevators and further delaying the start of corn planting in many areas. Crests on the swollen Mississippi and Illinois rivers were not expected to arrive until Sunday at the earliest in northern areas and several days later further south. "The crest here right now is forecast by the middle of next week, but there is some rain in the forecast so we'll see if that changes," said Michael Petersen, spokesman for the Army Corps' St. Louis district. "Once the crest has passed and the water has dropped below the mark that we have to shut it down, and if we know that it's not coming right back up, we should be able to open them up within 24 hours," he said. On the Illinois River, Dresden Island, Starved Rock and T.J. O'Brien locks were closed due to high water while Marseilles lock and dam was closed after nine barges broke away from a tow in record floodwater late on Thursday and struck the dam. Four of the barges sank and three, including one carrying caustic soda, remained afloat, said Ron Fournier, a spokesman for the Army Corps' Rock Island district. The dam may have been damaged but an assessment cannot be done until the water recedes and the barges have been removed. As of Friday, two had been towed from the waterway, he said. Seven Mississippi River locks, from Lock 16 at Muscatine, Iowa, to Lock 22 at Saverton, Missouri, were closed between Thursday evening and Friday morning as water overtopped dams, said Rob Germann, operations manager for the Army Corps' Mississippi River project, Rock Island district. The Corps also was not allowing vessels to pass through lock 15 at Rock Island, Illinois, because they would be unable to pass below a railroad bridge adjacent to the lock. Downriver locks 24 and 25 on the Mississippi River were forecast to close on Saturday, halting commercial navigation on the major shipping waterway north of St. Louis. Grain prices at Gulf of Mexico export terminals spiked as shippers scrambled to get enough grain to load ocean-going vessels, but prices fell in the Midwest as the grain backed up at elevators. Prices for spot barge shipments of corn at the Gulf surged by more than 10 cents a bushel late this week to a one-month peak as shippers scrambled to get their hands on enough grain to load ocean-going vessels. Spot soybean barge premiums at the Gulf also rallied 10 cents or more to their highest point since January when it looked as if the then parched Mississippi River would be closed. Cash prices offered to farmers fell at some river elevators as barge traffic ground to a halt. At a terminal along the Mississippi in Savanna, Illinois, soybean basis bids plunged by 33 cents a bushel to a three-week low during the last two days. "We can't load anything out," said a grain merchant across the river in Davenport, Iowa. The locks are closed so we are not going to move anything anyway. Barge brokers on Friday pulled their freight offers on the Illinois River and the Mississippi River north of St. Louis until the last week of April. The latest river forecasts from the National Weather Service suggest the lock closures will persist until at least next Wednesday. Additional reporting by Michael Hirtzer in Chicago; Editing Jim Marshall, Toni Reinhold