Gulf of Mexico

LA - Rerouting the Mississippi River could build new land—and save a retreating coast

Rerouting the Mississippi River could build new land—and save a retreating coast

In a swamp at the edge of Louisiana’s Barataria Bay, plastic-capped GPS antennas sprout like oversize mushrooms from four small wooden platforms. The gear, which helps scientists monitor changes in the surrounding marsh, is easy to miss in this expanse of water and swampland the size of Delaware. But it represents something even bigger: the beginnings of a grand ecosystem engineering experiment that has been 50 years in the making and could ultimately cost some $50 billion.

If all goes as planned, 2 years from now engineers will punch a massive hole in a nearby levee that holds back the Mississippi River. A 3.5-kilometer-long canal will carry sand and muck from the muddy river into the bay, helping rebuild vast wetlands eroded by sinking land and rising seas. Over 5 decades, researchers forecast that the project—formally known as the Mid-Barataria Sediment Diversion—could move enough sediment to bury the island of Manhattan under 3 meters of muck and create at least 54 square kilometers of new wetlands. The diversion, expected to cost $2 billion, is a critical part of a much larger effort aimed at preventing coastal Louisiana, and the human and wild communities it supports, from slipping beneath the sea.

“There’s nothing like [it] anywhere in the world,” says coastal geoscientist Torbjörn Törnqvist of Tulane University, one of a small army of researchers who have helped shape the project through years of fieldwork, computer models, and even the use of a giant replica of the Mississippi River in Massachusetts. “It’s going to be completely new.”

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