Wetlands restoration is key to avoiding the worst of future floods along the Mississippi
A changing climate poses considerable threats to many communities, and those along the country's major rivers are no exception, especially during floods.
The floods of today are carrying more water and lasting longer than they once did, experts say.
“All rivers naturally pulse, but we’re seeing higher peak flows, and longer days at that peak flow,” said Jill Kostel, a senior environmental engineer with The Wetlands Initiative. “We’re not dropping and recovering back down to base flow as quickly as we used to do.”
The Midwest acutely experienced this in 2019 when major flooding on the Mississippi and its tributaries inundated many communities, including those around the St. Louis region.
“It was the talk of the town,” said Alton Mayor David Goins. “It drew people. That’s not a great way to attract tourists, but people came from all over to see the flooding because it was one of the bigger ones since 1993.”
The existential threat from flooding is also an economic one for the cities and towns that hug the country's major rivers. In total, flooding in 2019 caused an estimated $6.2 billion in damage, including millions in the St. Louis region.
‘Our best attraction and our worst nightmare’
The magnitude of that flooding didn’t really hit Goins until he became Alton’s mayor a little more than two years ago, he said. Goins explained the city invested heavily to construct a flood wall to keep water out of Alton's historic downtown.
“It took a lot of manpower, and it took a lot of money,” he said. “Our riverfront is wonderful: It can be our best attraction and it can be our worst nightmare at the same time.”
This is the familiar reality for other communities that line the 2,340 miles of the Mississippi. And it comes as many of those same cities and towns are considering multimillion-dollar developments right along the river’s edge.
“People all over the world want to come and see this iconic natural phenomenon that is the Mississippi,” said Colin Wellenkamp, executive director of the Mississippi River Cities and Towns Initiative. “It has a larger international following than the Grand Canyon.”
The nation’s largest river is no longer seen as just a corridor for commerce, he said.
More and more, people want to enjoy the Mississippi and its scenery through activities like birding and canoeing, as well as in parks and public space right next to the water, Wellenkamp added.
Communities want to tap into this desire to attract tourism and business, but there’s one major challenge, he said: The Mississippi has been bouncing between times of too much water, during floods, and too little, when there’s a drought.
“Now the events are stacking up very close together and it’s either feast or famine,” Wellenkamp said. “So many of my cities have seen new projects wash away or get stuck in the mud because the water is way out there in the channel because it’s a drought.”
After the events of 2019, his organization started focusing more on wetlands restoration to better manage the river’s water. There’s about 66,000 acres worth of projects planned or completed in eight of the states the Mississippi traverses, Wellenkamp said.
One that’s been completed is at a place called Rasky Slough about 10 miles northeast of the Gateway Arch.
A small berm separates its 60 acres of tall grasses and shallow ponds from Horseshoe Lake in Illinois.
Mike Sertle, who manages Mississippi wetlands restoration projects for Ducks Unlimited, spies egrets, great blue herons and other birds among the vegetation.
“You know you’re in a wetland or near a wetland when the redwings are around,” he said.
Sertle explained that this slough, which his organization essentially doubled in size, can hold excess water during flooding and heavy rains, like what happened last July.
Water from Rasky trickles back into Horseshoe Lake before it eventually makes its way back to the Mississippi River.
“The goal is to mimic a natural system,” he said. “You want to dry it out every now and then, because it aerates the soil and we get a flush growth of vegetation.”
Those new plants then suck up more water.
But the restored habitat at Horseshoe Lake, which includes another project three times bigger than Rasky Slough, also adds habitat for birds and people.
“This is one of the most highly utilized public water fowling areas in the state, in addition to just public recreation in general,” he said. “There’s multiple people out fishing here every single day, people out here taking naps on their lunch break just enjoying the weather.”
From start to finish, the restoration at Rasky Slough cost about $250,000, but bigger projects can be more costly, Sertle said.
Ducks Unlimited is about to start a nearly 1,000-acre restoration a few miles to the west on Gabaret Island that sits between the Mississippi River and a bypass canal built by the Army Corps of Engineers. That project will likely cost between $5 million and $7 million, Sertle said.
“Investment in proper infrastructure in these wetlands systems, as we look [at] years of return, yeah we are seeing that it’s worth the upfront cost,” he said.
And wetlands have already been effective this year to stem flooding from rapid spring snowmelt on the Upper Mississippi.
Take the city of La Crosse, Wisconsin — it just experienced the third-highest flood on record, said Mayor Mitch Reynolds.
His city managed to avoid major damage with the help of wetlands, he said. New pumps helped move floodwaters from lower areas into nearby natural habitat.
“We’re lucky enough to have a marsh in the midst of the city that is basically our floodwater storage,” Reynolds said.
Other river city mayors see the benefits too.
“It’s important that we look to natural solutions to move the water because it’s more cost effective,” Alton Mayor Goins said. “It helps alleviate a lot of the costs involved in building a wall or something like that.”
And they give places for excess water to go instead of neighboring cities, he added.
Kostel, the environmental engineer, agrees.
“The cost benefit is so much more in terms of we’re not paying out damages, and we’re not paying out for new infrastructure,” she said.
It’s an approach to flooding that’s a clear departure from the past, when the primary solution would be building higher levees, Kostel said.
“Rivers always fluctuate, the nice thing is when it used to flood before we had levees, it would go out into its floodplain and the water would sit there and get absorbed in and then slowly released back into the river when the water receded,” she said.
Returning rivers back to how they naturally work isn’t just cheaper, but it can also help protect the cities, culture, wildlife and habitat that rely on them, she said.
“That’s how we’re going to get the flood management and the other benefits that we see with a river interacting with its floodplains and wetlands,” Kostel said. “It doesn’t have to be an all or nothing, we need to have a combination of solutions.”