Low Mississippi River creates 97-boat jam

(CBS/AP) MEMPHIS, Tenn. - The U.S. Coast Guard says 97 boats and barges are waiting for passage along an 11-mile stretch of the Mississippi River that has been closed because of low water levels.

Coast Guard spokesman Ryan Tippets told The Associated Press on Monday that the stretch of river near Greenville, Miss., has been closed intermittently since Aug. 11, when a vessel ran aground.

Tippets says that the area is currently being surveyed for dredging and that a Coast Guard boat is currently replacing eight navigation markers. He says 40 northbound vessels and 57 southbound vessels are currently stranded and waiting for passage.

Tippets says it is not immediately clear when the river will reopen. He says the stretch of river that has been closed was a possible site for more groundings.

Further upriver near Memphis, Tenn., there have already been multiple groundings due to low water levels, reports CBS News' Karen Brown.

The river is a superhighway for the nation's commodities. Barges transport 60 percent of U.S. corn for export, 45 percent of soybeans, 22 percent of gas, and 20 percent of coal. And one barge can move as much as 70 trucks.

"Everything depends on the river being open," says Derrick Smith, a 22-year veteran with the U.S. Army Corps of Engineers. "In high stages tow boats are like on a freeway all by themselves. They can maneuver anywhere you want. Today, towboats are basically on a one-way street. Have to pull over and wait for oncoming traffic, wait, slow down."

Smith says the Army Corps can keep the river open.

"We have dredges and we'll go out and dredge the low areas. $160 billion of cargo a year moves up and down this system. You have to keep it going. We do. We have to keep it going," Smith says.