How the Mississippi‘s headwaters impact damage from gulf coast hurricanes

CATHY WURZER: It is 12:24 here on Minnesota Now. Well, the Southeastern US definitely has captured our attention over the last month with the barrage of hurricanes that have passed through the region, causing mass destruction from wind and floodwater. The storms hearken back memories of the nation's last extreme hurricane. You might remember Hurricane Ida that ripped through the part of the Gulf Coast down there in 2021.

Well, Minnesota is more connected to the flooding and land loss that that region faces than you might think. The way we control the Mississippi River has serious implications on the future of that land. Minnesota journalist, historian Katie Thornton looked into that connection in a sprawling report about the politics of dams and levees in The Guardian. And she's with us to reflect on it. It's nice to hear your voice again, Katie. How have you been?

KATIE THORNTON: I have been doing well, Cathy. It's great to talk with you. Thanks for having me on the show.

CATHY WURZER: All right. Thanks for taking the time. Well, there's always a spark behind every story. What got you started on this one?

KATIE THORNTON: Yeah, I think, like any good story, I sort of had it kind of thrown in my face while I was working on something completely different and just having it totally captivate me for, in this case, years. As you mentioned, this story was really looking at the politics of levees and dams and how we fund climate change-related infrastructure. But it's told through the story of this one man down in Southern Louisiana, this man who worked for decades at a levee district, building a circular levee sort of surrounding his very Southern Louisiana home from surging waters from the Gulf of Mexico. And he ended up going rogue against some federal policies in order to build taller levees and ended up being-- that ended up being the only reason that his home area was saved during Hurricane Ida, when that terrible, terrible storm hit in 2021.

But as you mentioned, there's always some unusual spark. And so I really got interested in this years ago. I began the conversations. I, several years ago, was working at a cemetery in town doing local history research and ended up going on this year long Fulbright National Geographic project, looking at the ways we remember the dead and the changing places we remember the dead.

When I came back to the US, I was interested in how climate change is affecting our memorial practices and our memorial spaces. Ended up giving a call to somebody down on that region-- in that region, a cold call, who had done some work preserving a cemetery down there. He called me back. And it turns out, he ran the levee system down there. We ended up talking for an hour and a half that first time. And we just built up a relationship and a friendship. And I was able to learn that there was so much more going on down there.

CATHY WURZER: Wow. I love stories behind the story, of course. Thanks for-- that was quite a long and winding road here to this point.

KATIE THORNTON: It sure was.

CATHY WURZER: But I'm wondering-- you and I should talk about that research around the cemeteries and climate change, but that's another story for another time. So I'm curious then about getting back to the river now. I mean, the Mississippi really did build Southern Louisiana. All the sediment, for goodness sakes, from the river kind of has resulted in that creation of land, right?

KATIE THORNTON: Yeah, absolutely. I spent a lot of time down in Southern Louisiana for this story. It takes place about 90 minutes southwest of New Orleans, where there is still land, really the far reaches of the delta. But 5,000 years ago, the place where I was on the ground touring these levees with this sort of DIY levee builder, that was the Gulf of Mexico. It was in the water.

But in the intervening millennia, the Mississippi River brought all of this mud and silt and sand and sediment from 31 future states. And it sort of redistributed from the highlands and the hills near its headwaters and throughout the Central US and brought those-- brought that land, speck by speck, down to the bottom of the river. And it really did build Southern Louisiana.

I mean, for millennia, the river built about a square mile of new land every year as the river sort of brought the water out to sea and sort of left behind sediment, the same way you might have a little bit of buildup of sediment at if you have a spray bottle, for example. The liquid moves on. But the sediment sort of remains and builds up. That's the way the land in Southern Louisiana built up over the course of several thousand years.

CATHY WURZER: Right, So we have this system of levees and dams, for that matter, too. I mean, I can think of a number of dams. Well, just this year, a couple of dams have collapsed and crumbled. That whole system of locks and dams and levees, what does your research show? Maybe is it a good thing to continue this system or just let the river run wild?

KATIE THORNTON: Well, that is a really big question. And I don't know if I'm capable of answering it. But one thing that we do know for sure is that damming the river, letting the river sort of forcing it to stay in a single path really changes everything. I mean, it is what made it completely from the 17, 18, early 1900s when this was happening on the Mississippi River. It completely changed the trajectory of the country. It completely changed everything about trade, about all of our economy. On every sort of tributary to the Mississippi, people from the Rockies to Pittsburgh to Minneapolis and Saint Paul had access to European markets for the first time, starting in the late 1800s, because of the heavy engineering on the Mississippi River.

But rivers are super volatile. They want to just wind across the land. Their goal is to go from this curving, S-like path into something a little bit more straight and narrow and find the most direct route, gravity-resistant route to where they're going. And so every 1,000 years or so, the Mississippi River would just completely jump courses, especially in the lower Mississippi.

And you still see this. If you go on Google Maps and follow the Mississippi from the headwaters even just down to the Twin Cities, which is a very fun activity that I recommend everybody do, you'll see these sort of winds and these S-curves. But over time, the river cuts off those curves. It sort of finds shortcuts to itself.

And it leaves oxbow lakes. It leaves sort of U-shaped lakes a little ways away from the main channel. The river has done that on a really large scale throughout many, many millennia. And so by forcing the river into place, we really did change everything.

What had happened in the past is that, like we talked about, all of that sediment was flowing down the river. And it was building the land that became Southern Louisiana. But when you channelize a river and you force it into this narrow, single path, it forces the water to flow significantly faster. And when it gets to the end of the river, where, in the past, it would have slowed down and unraveled and built land in this sort of muddy mess, when you force it into a single channel, the water is flowing so quickly that, often, the sediments cannot build up land.

They don't slow down enough. They just sort of shoot off the continental shelf and into the ocean, where they can't build new land. Not to mention, you're trapping a lot of sediments behind the dams like we have up here in Minnesota and throughout the course of the Mississippi River. And so there's just less raw material to build that land.

CATHY WURZER: Listening to your talk here, gosh, it's really tough to control mother nature. I wonder then about the future of damming or rerouting the Mississippi. It doesn't sound like-- well, I mean, what are federal officials talking about?

KATIE THORNTON: Yeah, at this point, there have been studies, for example, that are looking at, what would happen if we were to remove some of these dams? I don't think, on the Mississippi, at least, it doesn't seem that many are gaining a lot of traction. And to be honest, at this point, just something like removing a dam would not immediately result in the replenishing of the land in Southern Louisiana.

And the land in Southern Louisiana is super important. Not only is it full of towns and life and history, there's also a lot of wetlands, which act as brake pads really for hurricanes. When hurricanes hit wetlands on the coast, they sort of act like a sponge. They disperse them and slow them down a little bit.

And so that's one of the reasons why we have more and more serious storms is because we've been slowing, originally slowing the growth of land in Louisiana, and then stopping it, and now losing it at a very, very, very rapid rate. But removing the dams would not immediately result in a lot of new land regeneration down in Louisiana. But there is a state and federally supported project right now to rebuild a lot of land by diverting part of the lower Mississippi into a channel where the river is sort of allowed to slow down and unravel again and rebuild some of that land. And they're looking at rebuilding several new square miles in the next couple, few decades.

CATHY WURZER: So quick final question here, because, of course, I'm watching with one eye here. I'm listening to you talk. And I'm watching all this video coming from Florida for Hurricane Milton. Obviously, the Mississippi doesn't have a direct connection to what is going on in Florida or Florida's land. But what did your reporting tell you about the federal government's role in protecting folks from natural disasters?

KATIE THORNTON: Yeah, exactly right. The Mississippi River did not build Florida. It did build Louisiana. But something that I think is really important to note, there is a lot of false information going on right now about the federal government not putting funding toward disasters or not funding sort of climate-related related infrastructure.

From very, very early on, the federal government has had a huge role to play in funding these controls on the river and the infrastructure on the river. Down in Louisiana, they funded 70% of the initial cost for the levee system that I was looking into. But I think what this story really gets at is that the dollars of the federal government are vitally, vitally important, especially in our changing climate.

But we also need to be listening to local expertise. What the federal government thought was appropriate in this area might have ended up, arguably, ended up not being quite right for them. They built higher. They went against the Corps specs. They self-funded their own levee district. And they ended up being able to save their district.

CATHY WURZER: Interesting story that you did. I appreciate your time here talking to us about it. Thank you so much, Katie.

KATIE THORNTON: Thanks for talking with me about the Minnesota connection.

CATHY WURZER: We've been talking to Minneapolis-based journalist Katie Thornton. You can find a link to her full report on our website, mprnews.org.