The Mississippi River, the largest U.S. river system, is forecast to crest today in Memphis, Tennessee, just below its 74-year-old record, as a bulge of water moves south toward the riverside refineries in Louisiana.

The Mississippi threatens 3,075 buildings, including 949 homes and 12 apartment complexes, in Tennessee's Shelby County, which includes Memphis, the Memphis/Shelby County Emergency Management Agency said yesterday. Exxon Mobil Corp. shut its fuel terminal in the city April 29, Kevin Allexon, a company spokesman, said in an e-mail.

"A big monster is rising up on the downtown shores and wrapping its arms around the city," said David Shular, a spokesman for Shelby County. "There are crowds of people along the riverbank just to look at it because they just haven't seen it this high."

The river is forecast to reach 48 feet in Memphis at 7 p.m., compared with the old mark of 48.7, according to a revised National Weather Service forecast.

"Essentially it is beginning to crest right now," said Bill Borghoff, an NWS meteorologist in Memphis. "We expect it should remain near 48 feet through Wednesday night or so."

Third-Largest Watershed

Heavy rains falling on ground already saturated by last winter's melting snow has caused flooding across the central U.S., said Jeff Graschel, a hydrologist with the Lower Mississippi River Forecast Center in Slidell, Louisiana.

The Mississippi River drains 41 percent of the continental U.S. and is the third-largest watershed in the world. Flooding along the river and its tributaries has closed roads and set crest records in New Madrid and Caruthersville, Missouri. Barge traffic stopped on the Ohio River, which drains into the Mississippi at Cairo, Illinois, last week.

The water has the potential to close oil operations in the New Orleans-to-Baton Rouge region, which has 11 refineries with a combined capacity of 2.5 million barrels a day, or 13 percent of U.S. output, said Andy Lipow, president of Lipow Oil Associates LLC in Houston.

David Fuller's view The flood risk to oil refineries has helped to push up crude oil and gasoline prices today. There are also problems for crops not least corn with farmers unable to plant in the worst affected regions.