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Our Views: Use the powerful tool of Mississippi River to rebuild wetlands

This schematic map shows the features of the proposed Mid-Barataria Sediment Diversion, including new wetlands, in yellow, created with sediment dredged from the diversion path. (Louisiana BP Trustee Implementation Group)

Posted on January 9, 2023

This schematic map shows the features of the proposed Mid-Barataria Sediment Diversion, including new wetlands, in yellow, created with sediment dredged from the diversion path.

After the Great Flood of 1927, and the subsequent construction of levee systems for protection of Louisiana from high water, it was recognized that restrictions on water flow affect the dispersal of sediments coming downstream in the Mississippi River.

Now, almost a century on, that levee-blocked process is going to be refocused on preserving Louisiana’s endangered coastal wetlands.

It’s time, and we hope that the much-discussed Mid-Barataria Sediment Diversion will be built as soon as possible to harness the river’s sediments, and build land on the coast the old-fashioned way.

Key permits for the project were awarded by the U.S. Army Corps of Engineers. They cover environmental issues and allow the project to impact levees, which is necessary if you are going to cut a channel in the river’s bank to move sediments into the upper Barataria Basin.

”It would be impossible to overstate the importance of the Mid-Barataria Sediment Diversion, so this is a huge moment for our entire state,” said Kim Reyher, executive director of the Coalition to Restore Coastal Louisiana. ”Finally, we are about to use the most important tool available to us: the mighty Mississippi.”

Mighty it is, as for centuries it was sediments from the river that created the land mass of southeastern Louisiana.

The diversion project proposes to cut the levee at Myrtle Grove for a two-mile-long concrete channel. Gates on the river would be opened when water flow is high enough to capture the greatest amount of sediment-carrying water moving along that section of the river.

As with the formation of Louisiana’s land in ancient times, the sediment is expected to drop out in open water to form land.

It will be a slow process but the goal, as the Coastal Protection and Restoration Authority has projected, would be to create 21 square miles of new wetlands by 2070.

The diversion’s cost of $1.9 billion — hopefully, although more cash is allocated if needed, given rising costs of many projects — is to be paid from funds provided by the oil company BP to mitigate natural resource damage caused by the 2010 Deepwater Horizon spill in the Gulf of Mexico.

The concept of diversions, building land with river sediments, is endorsed by CPRA and many leading coastal scientists. While experimental on this scale, the process is natural and sustainable.

Such a huge engineering project on the coast has drawn some criticism: Even with the allocation of $360 million to mitigate the impacts on fisheries and coastal villages, critics argue that its environmental costs will be too high.

The beautiful dolphins in Barataria’s waters are territorial and may not move on even as their habitat is destroyed, experts say; the Gulf’s seafood bounty, including oysters, may be severely impacted, others argue.

By and large, though, through a very extensive environmental-impact study, CPRA justified the project as the 21st century’s answer to the consequences of 20th-century levees.

”Communities we feared could be removed from the map in 50 years will instead see thousands of acres of wetlands in the future that will provide them with natural and sustainable protection,” Gov. John Bel Edwards said after the Corps permits were granted.

That, we think, is worth the costs of the Mid-Barataria diversion.


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