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Sierra magazine
Create | The Politics of Tomorrow

The Next Flood
Natural protection from unnatural disasters

By Carl Pope

Carl Pope In a few weeks, the spring melt across the upper Mississippi Valley will course down the Ohio, the Tennessee, the Missouri, and the Red Rivers into the mighty Mississippi. Brown with silt and laden with fertilizers and pesticides, the waters will surge against thousands of miles of levees. Depending on how much rain falls as the snow dissolves, some--perhaps many--of those levees will likely be overtopped or fail. The media will cover the "natural disaster" as small communities and farmlands are flooded. Governors will ask for federal aid, and families will suffer.

This would be the best-case scenario. Worse ones are quite possible. Consider these facts, courtesy of the Army Corps of Engineers:

  • At spring peak, 2.7 million cubic feet of water per second flow down the Mississippi. Only 1 million can pass through the river's main channel at New Orleans. The rest must find another outlet to the Gulf of Mexico.
  • If springtime floods are as heavy as they were two years ago, and if the agricultural levees on the upper Mississippi hold, the river will crest more than 10 feet above the levee at the Gateway Arch in St. Louis, and a second major U.S. city will drown. If, by a twist of fate, the water should crest just downstream from the levee at St. Louis, the river will barrel in full flood toward the Gulf, and New Orleans will be inundated again.
  • Half the silt that used to flow down the Mississippi now clogs federal dams on the upper Missouri, slowly eliminating their hydroelectric capacity while simultaneously starving Louisiana wetlands of the life-giving sediment they need to rebuild in the face of the ever-rising Gulf.

Our power to change this situation is limited. Since New Orleans was founded by Bienville in 1718, the channel to the Gulf has lengthened. Today the Mississippi River relentlessly seeks a shorter pathway to the sea--west to the Atchafalaya. Eventually it will get there, but the Army Corps of Engineers seeks to postpone the day with a massive levee system.

Unfortunately, the New Deal engineers who built Ft. Peck and the other upper Missouri dams didn't understand the implications of silt storage. We must now start managing those dams to get sediment out of them and back into the river--or soon we will have neither usable dams nor most of southern Louisiana.

Historically, the corps has treated the Mississippi River like a plumbing problem, ignoring its natural systems in favor of construction projects. To fix it, we need to let it act like a river again. It's become like a human with atherosclerosis, its arteries and floodways clogged. We need to tear down many levees and dramatically expand the floodplain, leaving room for wetlands. Low-lying communities, except for the biggest cities, should be moved to higher ground. As it is now, if the levees protecting soybean fields hold, St. Louis will die. If the cotton fields don't get flooded, New Orleans will go under.

Coastal communities can also enlist nature as a shield against hurricanes coming from the Gulf. Restored barrier islands could shelter coastal wetlands and cypress forests, which in turn would buffer towns and cities. Harnessing these powerful natural tools would require the corps, the shipping industry, and oil and gas operators to get into the restoration business. Drillers could do most of their work with hovercraft, but aren't required to, so they keep on dredging channels that destroy wetlands and funnel storm surge right into coastal towns.

Engineering alone can't prevent natural disaster. Computer models show that building higher levees without restoring wetlands will simply shift storm surge and flooding north into Mississippi, as happened with Katrina. We need a sea change in the way we protect Gulf Coast communities. Only by enlisting nature can we protect ourselves.

It's not like we don't understand. In the words of Lt. Gen. Robert L. Van Antwerp, head of the Army Corps of Engineers, "the river's going to do what the river's going to do." We need to learn to work with it, not against it.

Carl Pope is the chairman of the Sierra Club. E-mail carl.pope@sierraclub.org.

Photo by Kira Stackhouse

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