The controversial plan to unleash the Mississippi

However, the LSU report became best known for its proposed solution, which focused on tackling levees. The authors suggested diverting some water and mud from the Mississippi back to the marshland. Let the river resume the work it has been doing for thousands of years, in other words, before it was held back. An idea that has fascinated engineers and ecologists ever since.

To test the concept, scientists began cutting through the natural banks near the river’s mouth. (Because the land near the mouth was so incurably swampy, levees were never built along the last few dozen miles of the river.) In the late 1980s, the US Army Corps of Engineers was working on a major “diversion” at a site called Caernarvon , just upstream from Plaquemines Parish: Here a series of gates allow water to flow through a tunnel under the dam and into the swamp. The official purpose of the project is to provide fresh water to the swamp’s delicate plants. However, when construction began, local newspapers described the project as a potential channel for sediments – not just a way to preserve swamps, but also rebuild it. In fact, just a few years after the gates opened in 1991, hundreds of acres of new swamps had formed.

In the meantime, the federal government had begun to fund other restoration projects as well. Soil dredged from the river was dumped along the shore; Rock walls were built along eroding beaches; new sand has been added to the offshore islands that lie just beyond the delta; A second small freshwater diversion was built. But those efforts weren’t enough to do what many thought was necessary: ​​build the kind of large diversions that entire sub-deltas could construct.

Then, in late 2005, Hurricane Katrina swept through New Orleans, stirring up enough Gulf waters to submerge much of the hilltop city. Many scientists have suggested that the missing marshland may have absorbed some of the force of the storm-driven waves and acted as a kind of speed bump for hurricanes. Ecological arguments had never led to significant action, but damage to private property turned out to be different. Three months after the storm, the state formed a new agency, the Coastal Protection and Restoration Authority (CPRA), to oversee both coastal restoration and flood control.

The next year, an official from the agency approached Plaquemines community leaders to discuss a proposal for a large-scale diversion. The state wanted to build the diversion near the community of Myrtle Grove, a cluster of luxury homes on stilts above the swamp in Barataria Bay. The local response — from the fishing industry, from the local oil companies, from the farmers who grow citrus here on the ridge, and from homeowners — was like that Times-Picayune at that time an almost unanimous “no, thank you”.

The bad blood goes back generations to a massive flood that rolled down the Mississippi River in 1927 and inundated much of the southern United States. This was Hurricane Katrina of that time, a disaster that caught the nation’s attention. As the floodwaters approached New Orleans, officials were given permission to use dynamite to go downstream and blast a hole in the Mississippi levee that had grown so large it was now considered a problem. The flood water, trapped, was getting higher and threatened to overflow the dam crest. City officials hoped that if they gave the water another outlet, the water would fall near New Orleans. In fact, the town was spared, although the parish of Plaquemines was inundated. Residents were promised compensation for the damage, but nothing came of it.

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