Environment
4:09 pm
Wed May 8, 2013

Where Does The Mississippi River Set Down Its Mud?

This image from spring 2001 shows the plume of sediment pouring from the Mississippi River into the Gulf of Mexico.
Credit NASA
Eve Troeh interviews Bob Marshall of The Lens.

In a new story out in The Lens today, environmental reporter Bob Marshall delves into an ongoing study about Mississippi River sediment, and its ability to rebuild the coast. Government agencies and scientists have some new ideas about how much mud and sand the Mississippi River deposits along the Louisiana coast before it flows out to the Intercontinental Shelf.

Marshall tops his story by laying out some assumptions:

If there’s one underlying assumption that’s been used to justify the $50 billion cost of Louisiana’s Coastal Master Plan, it’s this: We actually have a chance to prevent southeast Louisiana from drowning in the Gulf because the Mississippi River carries the mud and sand necessary to keep pace with sea-level rise.

Turns out that assumption was a best guess.

In fact, the definitive evidence for the state’s claim that the river carries hope for the coast is just now being collected. A small army of state and federal researchers has embarked on  the first-ever comprehensive study of the lower river.

When the five-year study on sediment loads is completed, there will be a much clearer picture of how much sediment the river carries, and where it goes — or doesn't go. Marshall says the bad news is, the sediment may not go where we need it most. But the good news? We know where it's sitting. "So there's a deposit, basically, in the bank of this stuff that we need to spend," he says.

This news content made possible with support from the John S. and James L. Knight Foundation.

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