New Orleans — 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.

The Mississippi River Hydrodynamic and Delta Management Study is a massive $25 million, five-year project begun in 2011 that seeks to provide detailed information about the building materials that today’s river can offer restoration projects. In particular:

  • Where and how those projects should be managed.
  • How effective they can be in building and protecting land in the adjoining basins.
  • How they will affect the U.S. Army Corps of Engineers’ traditional river responsibilities of navigation and flood control.

The restoration effort relies centrally on diversions, places where the levees lining the Mississippi River will be breached to allow sediment-rich waters to flood and replenish adjacent basins, creating coastal marsh and new land. Currently, nine such diversions are planned between New Orleans and the Gulf.

More of this story at The Lens, an independent, nonprofit newsroom serving New Orleans.

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Historic study to find out what the Mississippi River really carries to help coastal restoration