Published: May 12, 2011 6:56 PM EDT
Updated: May 12, 2011 3:56 PM EDT

BUNCHE'S BEND, La. (AP) - The rising Mississippi River is sending water pouring over a levee in Louisiana, flooding 12,000 acres of corn and soybeans.

The flooding is taking place despite frantic efforts by farmers to shore up the levee, which is a century old.

Downstream, officials with the Port of New Orleans say the Coast Guard could close the river to ships as early as Monday. It would stop traffic on one of the world's busiest commercial waterways.

Barges headed south from the nation's heartland would be unable to reach grain elevators. Massive ships that carry U.S. corn, soybeans and other crops out of the country would be unable to move.

Crews are using tubes filled with water to help support the levees protecting downtown Baton Rouge, La. Along a portion of the French Quarter riverfront in New Orleans, sandbags are being put in place -- though the city isn't expecting a major impact from the flood.

The river swamped low-lying neighborhoods in Memphis, Tenn., earlier in the week.

The flood crest is expected to push past the Delta by late next week.

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