Moving the Mississippi: would changing the river's course help save the vanishing coastline of Louisiana?

• Author: Dean, Cornelia
• Position: Mississippi River

For thousands of years, the Mississippi River has acted like a conveyor belt, carrying millions of tons of sediment downstream each year. And before its flow was controlled, the river meandered across the region, spreading its nutrient-rich contents along coastal Louisiana.

But since the 1820s, when the U.S. Army Corps of Engineers began building levees and dams for protection against flooding, the Mississippi River has essentially been trapped and artificially channeled into the deep waters of the Gulf of Mexico.

As a result, the wetlands and barrier islands along Louisiana's coast, which were once regularly replenished by river sediment, have begun to deteriorate--and disappear.

Scientists have long said that the only way to restore Louisiana's vanishing coastline is to undo the elaborate levee system and divert the river to the sediment-starved marshes below New Orleans to the southeast.

The idea, previously dismissed as impractical, too expensive, and lethal to the region's economy, is now gaining widespread support. State officials are embracing it, motivated not only by the lessons of Hurricane Katrina but also by fears that global climate change will bring rising seas and accelerated land loss.

HUGE IMPLICATIONS

The best way to protect against future storms, officials now agree, is to allow the muddy river to dump that rich sediment where it's needed most. The hope is that this would slow or even reverse the land loss along coastal Louisiana.

But the...