NEW ORLEANS -- The Coast Guard has interrupted shipping along the major artery for moving grain from farms in the Midwest to the Gulf of Mexico over fears that the bulging Mississippi River could strain levees that protect hundreds of thousands from flooding. Already, thousands have sought refuge from floodwaters up and down the river.
The Coast Guard said it closed the Mississippi River at the port in Natchez, Miss., because barge traffic could increase pressure on the levees. Heavy flooding from Mississippi tributaries has displaced more than 4,000 in the state, about half of them upstream from Natchez in the Vicksburg area.
Several barges were idled at Natchez at the time of the closure, and many more could back up along the lower Mississippi. It wasn't clear when the river would reopen, but port officials said the interruption could cost the U.S. economy hundreds of millions of dollars per day.
The closure is the latest high-stakes decision made to protect homes and businesses that sit behind levees and floodwalls along the river. To take pressure off levees surrounding heavily populated New Orleans and Baton Rouge, the Army Corps of Engineers opened the key Morganza Spillway, choosing to flood more rural areas with fewer homes. Another spillway near New Orleans was opened earlier, but it doesn't threaten homes.
Most residents in the path of the Morganza's floodwaters have heeded the call to leave their homes. Bernadine Turner, who lives in a mandatory evacuation zone near Krotz Springs, La., spent a third day Monday moving her things out. Water from the Morganza opening was not expected to reach the town about 40 miles west of Baton Rouge for several days, but most residents were taking no chances.
"There's no doubt it's going to come up. We don't have flood insurance, and most people here don't. Man, it would be hard to start all over," she said.
Economic pain from the flooding could be felt far from the South because of the river closure. During the spring, the Mississippi is a highway for towboats pushing barges laden with corn, soybeans and other crops brought down from the Ohio, Missouri and Mississippi river systems. Farm products come down the river to a port near New Orleans to be loaded onto massive grain carriers for export.
The Port of South Louisiana is the largest grain port the country, handling about 54 percent of U.S. exports. The port's operations director, Mitch Smith, said the extent of the impact from the Natchez closing will depend on how long it lasts and how many barges are trapped upriver.
"Definitely, if it is a long closure, we will feel an economic impact," Smith said.
At least 10 freight terminals along the lower Mississippi River between Baton Rouge and New Orleans have suspended operations because of the high water, said Roy Gonzalez, acting president of the Gulf States
Maritime Association. In many cases, their docks are already at water level or going under, he said.
Vessels scheduled to use the terminals will either have to wait out the high water or divert to other terminals or ports. Additional costs for delaying any one vessel routinely run $20,000 to $40,000 per day, port officials say.
It's not clear how long it will take for normal operations to return at Natchez and other terminals. The river is expected to crest Saturday in Natchez at 63 feet, down a half-foot than earlier predictions, but almost five feet above a record set in 1937. It could take weeks for the water to recede.
All along the Mississippi River, a small army of engineers, deputies and even inmates is keeping round-the-clock watch at the many floodwalls and earthen levees holding the water back. They are looking for any droplets that seep through the barriers and any cracks that threaten to turn small leaks into big problems.
The work is hot and sometimes tedious, but without it, the flooding could get much worse.
"I volunteered for this," said jail inmate Wayne McClinton, who was helping with the sandbagging effort in northern Louisiana's Tensas Parish. "It's a chance to get out in the air, to do something different. It's not boring like prison is."
Although the job requires 24-hour vigilance, Reynold Minsky, president of a north Louisiana levee district, said there are some places in his mostly rural district of forest and farmland where he will not ask anyone to go after sundown.
"Unless we've got a serious situation that we know we've found before dark, we don't ask these people to go into these wooded areas because of the snakes and the alligators," Minsky said while taking a break from helicopter tours of the levees. "That's inhumane."
Minsky's 5th Louisiana Levee District is plagued these days by "sand boils," places where river water has found a way through earthen levees and bubbled up on the dry side like an artesian well. He insists they are no reason for alarm. If the water is clear, as it has been so far, that means the levee is not eroding. Stopping the boil involves ringing it with sandbags.
In New Orleans, workers inspect the levees daily when the water is high to look for potential trouble spots. The levees there -- which are not among those that failed along canals after Hurricane Katrina -- have survived high water before and will survive this latest test, city officials said. The opening of the Morganza has stopped the river's rise at New Orleans, but the relief valve sent water gushing into the mostly rural Atchafalaya River basin.
"There's no question about it, New Orleans is safe, New Orleans is dry and the system's working as it was designed," New Orleans Mayor Mitch Landrieu said Tuesday morning on CBS' "The Early show."
For those in the path of waters let loose by the Morganza, a tense waiting game has begun. On Monday, 75-year-old Leif Montin watched a truck tow away a storage pod containing most of the furniture he and his wife have in their home in Butte Larose, a community emptied by residents fleeing the rising waters.
"I guess you guys are ready to get out of here," the driver said to Montin.
"Yep. Pretty much," responded Montin.