After record-breaking floods, preventing the next one isn’t so cut and dry
The record floods that swept through the St. Louis region just after Christmas claimed at least two dozen lives in Missouri and Illinois. In four counties near St. Louis, the water damaged 7,100 homes, businesses and public buildings, according to early estimates. As communities clean up and rebuild, attention is turning to how these disasters can be prevented. But the answers are never simple.
“I think they need to do something about this river,” said Jodi Howard, a resident of Pacific, which sits along the Meramec River. “I mean, Valley Park got a levee. Why can’t they protect what they own?”
Valley Park does have a levee, a 45-foot-high, 3-mile long earthen behemoth. The day before the river crested, worries that the levee could fail ran high. Mayor Mike Penisse issued an evacuation order for about 900 people living in the lower end of town. The water rose within a foot of the top of the levee, and it held. As residents streamed back into town after the river crested, Penisse said he and a group of city employees were there to greet them.
“I seen ladies crying, that they were just so happy to come back in that they came back in to a dry house,” Penisse said. Only a few of the town’s buildings that were outside of the protection of the levee were damaged.
The experience is a far cry from Valley Park’s experience during the 1982 flood, which prompted a campaign to build the levee in the first place.
“The water come up, they didn’t realize it was going to get as high as they said, and next thing you know people were in the second stories of their houses, trying to get out,” Penisse said.
With authorization from Congress and $35 million in federal funds, the Valley Park Levee was built by the Army Corps of Engineers. According a 2010 budget document, upkeep and expansion has brought the levee’s total cost to about $53.7 million. When the levee isn’t keeping floodwaters at bay, it functions as a public park—with large trees, picnic tables and a bike path.
Despite the cost, levees are frequently used as barriers between rivers and cities built on a floodplain, such as the fortified Monarch-Chesterfield Levee, which is intended to withstand a 500-year flood. They are, however, no panacea. Levees can fail, as one did during the New Year’s floods in Ste. Genevieve County, sending water unexpectedly into the town of St. Mary. Levees can also be overtopped, as they were in West Alton, which sits at the confluence of the Missouri and Mississippi Rivers. And many will argue that too many levees just push the water higher, making floods more frequent and more severe along overly developed rivers. That’s not to mention the ecological toll of converting verdant floodplains to subdivisions and parking lots.
In a 2008 article, a Southern Illinois University geologist, Nicholas Pinter, tried to tease out the human variables that contribute to floods in his research along the Mississippi River. (Pinter has since taken a position at the University of California-Davis). Climate change and industrialization, he found, can account for a few extra inches during a flood on the Mississippi. The river’s levees, by comparison, send it up 3 or 4 feet. But the biggest difference is due to river navigation systems like wing dikes.
“The Middle Mississippi River is intensely engineered. With the result that any flood that comes through, you have to ask the question—how much of that is natural, the rain in the contributing basin, and how much is the effect of humans modifying that system,” Pinter said.
If we could go back in time, he said, the solution is obvious: Don’t build in a floodplain. But that’s what people have done, and levees are here to stay, so he recommends a three-part “sniff test”:
“They should be used for infrastructure that is concentrated, high in value and pre-existing. We should not be taking open floodplain and putting it behind a wall anywhere. That’s a field of dreams approach that has put us in this position,” Pinter said.
But in the St. Louis region, floodplains are constantly under development. A 2005 review of Landsat satellite data, funded by the St. Louis Post-Dispatch, showed three-quarters of all development in the seven-state swath of land flooded in 1993 occurred in Missouri. New investment topped $400 million in the Chesterfield Valley alone.
Bob Holmes of the United States Geological Survey in Rolla said that levees can be built in a responsible way, without a major effect on flood levels in other places.
“It’s a societal decision to protect a certain area,” Holmes said. After all, floods are a natural occurrence.
“It comes down to, you know, we gotta live on the planet, you have to have food, so we always have to do these tradeoffs. Hopefully we do that in a smart way,” Holmes said.
That’s why many riverside communities will hold buyouts—where flooded homes get bulldozed instead of rebuilt, and newly created green spaces can absorb floodwaters. But what happens when one town builds a wall, and the other doesn’t? Who should decide who floods and who stays dry?
During a press conference last week, Missouri Governor Jay Nixon said these are decisions for later down the road, because they would require federal buy-in. Nixon said he thinks the cost of flood insurance does a fair job of curbing floodplain development, and doesn’t think a statewide policy against it is necessary—though many other states do.
“I would be very hesitant to, in a blanket way, when we have such a significant outdoor tourism industry that relies on business in the summer especially on our rivers and streams to say that you can’t build there or put structures there,” Nixon said.
In the meantime, Nixon said his main focus is flood recovery—so that towns along the Meramec, Missouri and the Mississippi can get back to normal as soon as possible.
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