During the Great Flood of 1993, the Mississippi River crested at nearly 50 feet, the highest level ever recorded in St. Louis and nearly 20 feet above flood stage. Water lapped the steps leading to the Gateway Arch and would have swallowed downtown were it not for a massive floodwall built in the 1960s.
Twenty years later St. Louis is alternately inundated and baked dry with drought. In January the river was at its ninth lowest water level since record keeping began in 1861. Less than four months later, it was 40 feet higher, falling short of 1993 records by only a few feet at some locations.
St. Louis is just south of the confluence of the Missouri, Illinois and Mississippi rivers — 20 percent of the rain that falls on the continental U.S. flows past the city. Like many Midwest cities, it faces a future where both extreme flooding and drought are more common as a result of climate change.
Hurricanes Katrina and Sandy forced a conversation about climate change in coastal regions, but in the nation’s heartland the idea of global warming as an imminent concern remains a political nonstarter.
“Until a catastrophe happens that immediately affects St. Louis,” said architect and Washington University professor Derek Hoeferlin, “it’s difficult to get things to change.”
Hoeferlin is part of a team of designers and engineers trying to start a conversation about climate change and the Mississippi River. Continuing the Dutch Dialogues workshops underway in New Orleans since 2008, it recently held a conference in St. Louis on climate adaptation strategies for the Midwest River Basins.
Fredrik Huthoff, an engineering physicist who recently returned to the Netherlands after a stint at Southern Illinois University, drew parallels with the Dutch city of Nijmegen. Like St. Louis, it is also at the bottleneck of a major river system. Instead of building ever-higher levees, however, Nijmegen also widened the river to create a new island, and dug a side channel that acts as an additional buffer zone during floods. The system still needs levees, but the city faces fewer and weaker floods.
The team mocked up three scenarios for St. Louis, intending them to be provocative and not specific design solutions. The idea is to let the river flow more freely in certain places, creating a “multi-functional flood plain” more resilient to weather extremes.
That could involve stepping back suburban development along the city’s West side or planting water-tolerant crops in the agricultural lands around the three rivers’ confluence. As in the Netherlands, that kind of approach would involve property buyouts and land use changes. But it could also open new land for nature preserves, hunting or diversified local food production. Digging a separate channel east of the river — a “blue green by-pass” following the path of a historic river — would also relieve pressure on the entire Mississippi, while opening up new port opportunities east of St. Louis.
“Because of extreme weather we have these new design conditions of drought and greater variability,” said John Hoal, founding principal of H3 Studio and director of master planning for St. Louis’ 200-square-mile Confluence Greenway system. “If you keep reinforcing the levees as they are, and you don’t deal with the water drainage off the bluffs behind the levees, you get major problems behind the levee. The opportunity here is that you can live in an improved community with a vital economy, while providing some room for the river to run its course.”
A sketch of the confluence where the Mississippi, Illinois and Missouri rivers meet. In this scenario, the floodplain north of St. Louis would reevaluate land use, perhaps planting more water-tolerant crops.
It’s not the first time people have recognized the need for a new approach. In 1994 the U.S. Interagency Task Force on Floodplain Management published a report calling for a broad national floodplain policy that would have “all of those who support risky behavior, either directly or indirectly,” share the costs of reducing that risk. But while flood insurance providers and the Army Corps of Engineers have adjusted their programs since then, floodplain managers have largely had to muddle through in the absence of any national consensus.
The local community, however, has reacted with urgency. Facing a $150 million tab to fix several levees deemed unfit by the Federal Emergency Management Agency in 2007, three counties on the east side of the river voted to tax themselves to strengthen the levee system.
East St. Louis, which sits on the side floodplain known as the American Bottom, is an almost entirely black city where nearly half of residents live below the poverty line. Though their levees have been built up since the 1993 floods, American Bottom communities are still at risk. Dale Morris, senior economist for The Royal Netherlands Embassy, relayed a saying popular among hydraulic engineers: “There are only two types of levees: those that have failed and those that are going to fail.”
It’s a matter of risk perception. What experts call a “100-year flood” is a major flood that has a 1 percent chance of happening every year. Over the course of a 30-year mortgage, that same probability works out to a 26 percent chance of a major flood — meaning it’s more probable than not that a 100-year flood will occur during a lifetime. And climate change will force heavier floods, perhaps enough to overcome the new 500-year standard of the east side levees.
“People who live in those areas and who have started business there, they feel secure,” Huthoff said. “They are definitely at risk in the future.”
And levees don’t do anything to address the problem of drought. As part of the countrywide “Room for the River” program, the Dutch took their river system as a whole, instead of city by city. Inspired by some U.S. projects, such as Louisiana’s Atchafalaya Spillway, they focused their work upstream. Reservoirs store water during peak discharge. The system is engineered to naturally spillover into storage areas when water levels reach a certain threshold.
“You’re restoring the river back to what it wants to do,” Morris said. “It is likely better when safety systems are designed to operate naturally, based on water levels or flow conditions.”
A diagram of the water challenges facing St. Louis (left) and the American Bottomlands, east of the Mississippi.
By contrast, the Army Corps of Engineers is sometimes forced to take drastic measures, as when it dynamited the Birds Point levee in southeast Missouri. Some Corps infrastructure, like California’s Sutter and Yolo bypasses, already operate naturally to a large extent.
It gets to the heart of what many say amounts to a cultural difference between Dutch and Americans in how they deal with water.
Huthoff recalled his first encounter with the Mississippi. Before moving to Illinois, he managed river projects for the Dutch engineering firm HKV Consultants. When the Dutch Dialogues delegation came to St. Louis, it asked the locals what words they would associate with their city. St. Louisans hardly ever mentioned the river. “Gateway to the West,” and “The Arch” were common responses.
“The river is not really a part of that whole image,” Huthoff said. “It’s more like it’s a boundary between east and west, but not seen as a valuable entity itself.”
For Huthoff, who is originally from the Netherlands, the river was central to his idea of the country.
“To me, the Mississippi already sounded magical. It had so much tradition. When I was in Vicksburg, during a road trip, I stood there looking at the river and the sun was going down,” Huthoff said. “I really felt like, I’m here.”
Hoeferlin argues the river can play a vital role in urban revitalization. As population loss continues, St. Louis planners have turned their attention back to the city’s older areas for infill redevelopment. It’s not an issue of never building in the floodplain, he said, but of communities reclaiming the river as an asset, for all its floods and droughts. He points out the St. Louis metro region is roughly the same size as The Netherlands’ national Room for the River project area.
“Living next to water has tremendous economic value,” Hoeferlin said. “You have to manage it, though.”
All images copyright MISI-ZIBI: Living with the Great Rivers — Washington University in St. Louis and the Royal Netherlands Embassy Washington D.C.