FloodsAs Flood Risks Increase across the U.S., It’s Time to Recognize the Limits of Levees
Many U.S. cities rely on levees for protection from floods. There are more than 100,000 miles of levees nationwide, in all 50 states and one of every five counties. Most of them seriously need repair: Levees received a D on the American Society of Civil Engineers’ 2018 national infrastructure report card. Climate models show that flood risks are increasing, and across the central U.S., rivers are becoming increasingly hard to control. Faith in the idea of engineered flood control is starting to erode.
New Orleans averted disaster this month when tropical storm Barry delivered less rain in the Crescent City than forecasters originally feared. But Barry’s slog through Louisiana, Arkansas, Tennessee and Missouri is just the latest event in a year that has tested levees across the central U.S.
Many U.S. cities rely on levees for protection from floods. There are more than 100,000 miles of levees nationwide, in all 50 states and one of every five counties. Most of them seriously need repair: Levees received a D on the American Society of Civil Engineers’ 2018 national infrastructure report card.
Levees shield farms and towns from flooding, but they also create risk. When rivers rise, they can’t naturally spread out in the floodplain as they did in the pre-flood control era. Instead, they flow harder and faster and send more water downstream.
And climate models show that flood risks are increasing. During this year’s unusually wet winter and spring, dozens of levees on the Missouri, Mississippi and Arkansas rivers were overtopped or breached by floodwaters. Across the central U.S., rivers are becoming increasingly hard to control.
Remaking the Missouri
In my book, A River in the City of Fountains, I describe the complexities of flood control in Kansas City, which sits at the junction of the Missouri and Kansas rivers.
The Missouri, the larger of these two, is America’s longest river, rising in Montana’s Rocky Mountains and flowing east and south for 2,341 miles until it joins the Mississippi River north of St. Louis. Historically it was wide and shallow, full of sand bars and snags that created challenges for steamboats.
In the late 19th and early 20th centuries, Kansas City business leaders began lobbying for federal navigation subsidies to counter the influence of the railroads. Until the river could be narrowed and deepened, navigation was unreliable. And without levees, industry in the floodplain was at risk.
