Tracking the impact of the Bonnet-Carre Spillway on Mississippi’s seafood

What is the Bonnet Carre Spillway?

The Mississippi Sound Coalition is in a legal battle with the U.S. Army Corps of Engineers about the opening of the Bonnet-Carre Spillway in Louisiana.

But what exactly is the Bonnet-Carre spillway?

The spillway is located on the Mississippi River between New Orleans and Baton Rouge.

The spillway is used to relieve areas around the Mississippi River as it floods by opening the spillway, which allows flood water to flow into Lake Ponchartrain and into the Gulf of Mexico. 

How did it affect the Mississippi Gulf Coast?

When the floodwaters are diverted to Lake Ponchartrain, however, it spells trouble for the seafood industry on the Mississippi coast.

Coastal governments claim opening the Bonnet-Carre Spillway harms fishing habitats.

A lawsuit was brought on by the local governments, fishermen, and tourism businesses damaged by more frequent opening of the spillway.

The lawsuit was filed in 2019 after an opening of the spillway caused an algal bloom in the Mississippi Sound and the oyster mortality rate began to rise. 

The Mississippi Department of Marine Resources will pay out more than 6 million dollars for any commercial fishermen and seafood dealers who were affected. 

What’s happening now?

Most recently, the Mississippi Sound Coalition, which is made up of cities and organizations across the Gulf Coast, has filed a rebuttal after the corp claimed the opening of the spillway caused minimal damage.

The coalition says the opposite is true, and plans to prove it using research from two universities. 

Heres how researchers at the University of Southern Mississippi is tracking Bonnet-Carre’s impact and what they envision for the gulf’s future.

Researchers at the University of Southern Mississippi have created a way for us to see what happened in the gulf when Bonnett-Carre opened in 2019, and it may just be the proof the Mississippi Sound Coalition needs.

“When the model had the Bonnet-Carre spillway open, you can see that there is a larger extent of the freshwater into the sound,” said Researcher and PhD student Brandy Armstrong. “It actually at one point spreads down from the western sound to Mobile Bay almost. So, the whole sound was full of fresh water.”

2019’s destruction was more than just the spillway opening. It was how long it was opened and how much water entered Lake Ponchartrain, Hurricane Barry pushing that water towards us, and dozens of other elements.

These researchers have tracked it all and laid it out for everyone to see.

“It really is all tied together,” said researcher and professor Dr. Jerry Wiggert. “This model allows us to start to pull apart how sensitive things are. What happens here affects here.”

The group can create models of what would happen day by day if the Bonnet-Carre was opened again – and each day looks different.

“Just because 2019 was very devastating, that doesn’t mean that every bonnet-carre spillway opening has the same effect on marine life,” said researcher and professor Dr. Kemal Cambazoglu.

Unfortunately, there is no surefire way of knowing how the Bonnet-Carre will affect the Mississippi Gulf Coast in the future, but these scientists work alongside biologists to gather data that can help us rebuild.

Data is collected like temperature, current salinity, and more so USM can create these models.

The goal is that other marine biologists and scientists can make the best decisions based on these predictions to save Mississippi’s marine ecosystem.

“There is potential for restoration and recovery over time, and that’s actually what we’re trying to do,” Dr. Cambazoglu said. “Working with all stakeholders, trying to provide science-based guidance to them. So, our research and our findings actually help them better understand the area.”