One of the ways the state plans to rebuild land on the Louisiana coast is by sediment diversions -- diverting the silt, sand, and dirty waters of the Mississippi River into the marsh.
For years, many in the commercial fishing industry have claimed that the influx of freshwater funneled through diversions would ruin their industry. Now, some fishers feel they have proof: the damaging impacts of the 2019 Mississippi River Flood.
The Mississippi River Devastated Fisheries This Year. Some See It As A Preview Of The Future
On a bayou in the St. Bernard Parish town of Yscloskey, George Barisich starts up his shrimp boat.
“Hear that?” he says, as the diesel engine below our feet roars to a start. “That's the sound we want to hear.”
Barisich says that engine hasn’t gotten much use lately. There is no point in heading into the marsh when there aren’t any shrimp to catch.
“I'm 82 percent off on my brown shrimp,” he says of this season. “Eighty two. And there's a lot of people just as bad.”
This year’s historic flooding on the Mississippi River has decimated the coast’s fisheries.
Shrimp, oysters and other species need a mix of salty and freshwater to survive. To keep the river levees safe, officials opened the Bonnet Carre Spillway for more than 120 days this year. That added a ton of extra freshwater into the environment, which has ruined the delicate balance.
The negative impacts have been so bad, the governors of both Louisiana and Mississippi have declared fisheries disasters and are seeking help from the federal government to help commercial fishers in both states.
Barisich worries disastrous fishing seasons are going to become regular events if the state builds sediment diversions.
“What you see here is a snapshot of what you're gonna see,” he says. “This is a picture of what you're going to lose every time you [operate sediment diversions].”
Though not the only strategy for combating coastal land loss, sediment diversions are the state’s cornerstone solution. The basic idea is to use the sediment that’s already floating around in the Mississippi River. Engineers plan to cut a hole in the river levee and divert some of the water through a channel into nearby marshes. Over time, the sediment will pile up and naturally build land.
That means a lot more freshwater will be gushing into the estuary every year. For Barisich, sediment diversions sound a like the Bonnet Carre Spillway. Which is to say: potentially devastating.
The state, of course, disagrees. Several diversions have been proposed, but none have been built. The state is currently designing and applying for permits for the first two. Bren Haase is the Executive Director of the Coastal Protection and Restoration Authority (CPRA).
“The amount of water that we're talking about with sediment diversions,” says Haase, “...pales in comparison to what we've seen moving through the Bonnet Carre Spillway, and even out of the mouth of the river itself this year.”
Haase says comparing the unprecedented flow of freshwater coming out of the Mississippi River this year to the flow proposed through sediment diversions is like comparing a fire hose to a garden hose. Less water will mean lesser impact -- not a preview of what diversions will do.
Louisiana’s coast is disappearing at a famously rapid clip, and the state says sediment diversions are essential to rebuilding the coast in a sustainable way. Several environmental groups agree, like the Environmental Defense Fund (EDF).
A couple years ago, EDF assembled a team of scientists to figure out how to use diversions to build land, while also minimizing their negative impacts on the environment and fisheries. Natalie Peyronnin Snider, EDF’s Senior Director of Resilience, says the goal of the study was to shift the diversion conversation away from whether or not diversions should be built to “how do we open and close the gates of it.”
“What we found is that winter operations and winter peaks...could build land, could get sediment out into the basin,” says Snider, “but was also less harmful to some of the fishery species.”
Using diversions in the winter is just one recommendation from EDF’s report. Overall, the report concluded it’s possible to both build land and maintain harvestable fisheries for people like George Barisich.
“Number one, I've heard it all before,” says Barisich with a chuckle.
Barisich is familiar with that line of thinking, and ultimately still feels like sediment diversions are an unnecessary risk -- with an entire industry and way of life on the line. He’s seen the damage freshwater can do, repeatedly, and doesn’t trust the state to manage diversions in the interest of commercial fishers.
“I'm just a hardheaded Croatian, I'm not going to be told [stuff] that's going to try to make me believe something that I know is not true.”
Barisich says the state should focus on building coastal land other ways, like artificially creating marshes from dredged sediment, which it already does.
At the very least, he wants some assurances from the state before sediment diversions are built. Like money set aside for commercial fishers, which could be used to make up for any negative impacts.
The state has not yet outlined how it might mitigate possible negative impacts -- but says a number of options are on the table. Some of those could be outlined in the environmental impact study of the Mid-Barataria Diversion, the first of the proposed sediment diversions. The state expects the first draft of that to come out in about a year.
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Correction: The original post for this piece wrongly identified Natalie Peyronnin Snider.
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