SCIENCE -- May 3, 2011 at 5:00 PM ET
Levee Blast Floods Missouri Town, Spares Others Along Mississippi River
Flooding near Cairo, Ill.; U.S. Coast Guard courtesy photo
The tiny town of Wyatt, Mo. lies at the easternmost part of the state, flanking the Mississippi River. It is a rich farmland, consisting of corn, soybean and rice fields. Directly across the river is Cairo, Ill., a city eight times as large, and surrounded by levees.
On Monday night, the Army Corps of Engineers stuck explosives into levee pipes, and blasted a gaping hole through one of the levees. The Mississippi River poured into Wyatt, submerging more than 130,000 acres of farmland. On the Cairo side, as expected, the river level dropped about two feet.
The purpose of the planned breach: To spare Cairo from more extensive flood damage by flooding this section of Wyatt, called the Bird's Point-New Madrid floodway.
By Tuesday morning, floodwater had seeped into every one of the 90 homes in this floodway, according to county officials.
"You can think of it as if you had a fish aquarium, and you chop out a section of the side," said Robert Dalrymple, a professor of civil engineering at Johns Hopkins. "The water would flow out that notch, and would lower the water level in the vicinity of the notch, because water flows downhill."
Even before the decision was made, water was rising to historic levels, placing millions in danger, according to a joint statement released on Tuesday by Agriculture Secretary Tom Vilsack and Federal Emergency Management Agency Administrator Craig Fugate.
"The Birds Point-New Madrid Floodway was designed and built 80 years ago to mitigate these conditions and provide a last safeguard for millions of Americans," the statement read. "Last night, that safeguard was utilized, sparing many from additional hardship."
A second planned breach occurred Tuesday afternoon, and a third is expected in the next 24 to 48 hours, said Mike O'Connell, a spokesman with the Missouri Department of Public Safety.
The 130,000 acres of Missouri farmland was established as a floodway in 1928. The federal government had purchased flood easements on the land, and has been since empowered to blow up Birds Point levee, if needed, to protect cities downstream and across the river in Cairo.
"It's sacrificing a few to save a lot," said Larry Larson, executive director of the Association of State Floodplain Managers.
The technique is common, and used worldwide to save areas from flooding, both legally and illegally. "China has a number of what they call "flood storage areas," where they intentionally blow levees to flood farmland, rice and paddies - some of them even have houses on them - to save industrialized cities further downstream," Larson said. Mississippi River Valley history, he added, includes accounts of people on rowboats trying to blow out levees with dynamite to save their land.
Missouri Gov. Jay Nixon fought this latest levee breach in federal court, but lost.
Residents had about a week to prepare and evacuate the area of people, animals and equipment.
"I think everybody is upset about it, but at the same time, it was one of those, if you will, necessary evils," said Drew Juden, public safety director for the neighboring Sikeston, Mo. "Nobody likes to lose their property or lose their livelihood. The only hope is that the Corps comes back and rebuilds the levee, and everything comes back to some sort of normalcy sooner or later."