The Mississippi River will likely linger just below 48-foot in Memphis through today before flooding flows south, threatening more communities, refineries and shipping traffic before emptying into the Gulf of Mexico past New Orleans in about two weeks.

The river reached what may its highest point in Memphis of 47.85 feet, just below the expected 48 feet, at 2 a.m., said Danny Gant, a National Weather Service meteorologist.

“We think it will hover right around that area, it might go a hair or two higher,” Gant said by telephone from Memphis. “We’re just going to stay right around there for 12 to 24 hours and then it is going to slowly start to fall.”

It will probably stay above flood stage of 34 feet for close to a month, he said.

Gasoline futures advanced, extending the biggest one-day gain in more than two months, amid concern that the flooding will disrupt fuel production and distribution. Futures rose as much as 3.1 percent, adding to a 6.1 percent gain yesterday, the the most since July 2009.

The rising water has interrupted coal shipments to power plants in Tennessee, flooded more than a 100,000 acres of Missouri cropland, forced thousands from their homes and prompted the Army Corps of Engineers to open the Bonnet Carre Spillway to reduce the river’s force through New Orleans.

Largest River

The Mississippi is the largest river system in the country, the third-largest watershed in the world and drains 41 percent of the continental U.S., according to the Army Corps.

“We are watching a system this nation has invested $13 billion in and we are watching it get stressed and tested to its limit,” said the Army Corps Colonel George Shepard on Bloomberg Television’s “InsideTrack” today. “Right now we can calculate we have had $351 billion of damages already prevented before this flood happened, so I think we have a good investment.”

To relieve the threat to New Orleans and Baton Rouge, Louisiana’s capital, the corps may open the Morganza Floodway. Opening the floodway halfway would inundate a swath of central Louisiana along the Atchafalaya River with 5 feet (1.5 meters) to 20 feet of water.

Spillway Opening

The opening of the spillway would affect two refineries, according to Governor Bobby Jindal’s office. One of the plants refineries, on the Mississippi River, could have capacity cut to 75 percent for two weeks, according to the state’s Department of Natural Resources.

Anna Dearmon, communications director at the DNR, said she couldn’t release the names of the refineries because of security reasons.

A refinery at Krotz Springs, Louisiana, may be affected by flood waters if the Morganza is opened, Andy Lipow, president of Lipow Oil Associates LLC in Houston, said yesterday.

Even before a decision on Morganza is made, 879 families have been told they should probably leave their homes in St. Martin Parish, according to Jindal’s office.

No decision has been made on whether to open the Morganza, said Rachel Rodi, spokeswoman for the Army Corps. When the Mississippi’s flow reaches 1.5 million cubic feet at the Red River Landing, about 60 miles upstream from Baton Rouge, the corps may decide to open it, according to corps information.

Oil Refineries

On the Mississippi between New Orleans and Baton Rouge, there are 11 refineries with a combined capacity of 2.5 million barrels a day, or 13 percent of U.S. output, Lipow said.

Royal Dutch Shell Plc will supply plants at Geismar and Norocol, Louisiana, by rail if the river prevents barges and ships from unloading, according to an e-mail statement from Alexandra Smith, a company spokeswoman.

Flooding stopped barge traffic on the Ohio River and north of Memphis on the Mississippi last week and has interrupted shipping south of the Tennessee city.

The Tennessee Valley Authority is facing a shortage in coal shipments at four units at its Gallatin power plant because high waters have closed a lock used to move barges up for unloading.

“The reserve at the plant is, say, 20 to 30 days of on- site coal reserves,” said Mike Bradley, a spokesman for the federally owned utility. “We expect the lock will reopen before those reserves are depleted.”

According to TVA’s website, the Gallatin plant consumes about 12,350 tons of coal daily.

Commodity Traffic

The Mississippi and Ohio rivers are also major delivery systems for commodities and crops such as corn, soybeans and other crops grown along their banks.

“Tennessee hasn’t seen flooding like this in 75 years,” said Lee Maddox, a spokesman for the Tennessee Farm Bureau. The northwestern part of the state, where entire counties are largely under water, is “the breadbasket row-crop area of the state,” with concentrations of corn and soybeans, he said.

“Corn is out of the question because that window is closing this week to keep up a good yield,” Maddox said. “Now their only option is soybeans, if they can get that planted in June.”