On a 64-foot-high concrete floodwall in Cairo, Ill., thick black lines denote when the Ohio River got too high:
“1937. 59.5 [feet].”
Nobody’s marked 2011 yet.
If snow hadn’t broken records, and rain hadn’t broken forecasts, the Missouri, Mississippi and Ohio rivers wouldn’t have swelled like they did this year. Cairo, Ill., gateway to the South, including New Orleans, wouldn’t have heard its banks slosh invasively.
But the water came, and the U.S. Corps of Engineers had to deal with not its rising height, but rather its two-million cubic-feet-per-second pressure pushing beneath the Birds Point levee.
Volcano-like structures called sand boils erupted fast because of the pressure. Although the Corps placed sandbags on these mounds to offset the pressure, the boils erupted too fast, indicating the river was getting out of control. The Corps was playing whack-a-mole against a river.
“You don’t deal with two-million cubic feet of water easily,” Corps Major Jon Korneliussen said. “You let it go where it wants to go.”
The Corps is assessing this fall whether or not opening the levee to relieve the pressure was appropriate.
— By Sarah Alban, Edited by Joe Pecoraro