"The Project Flood Is Upon Us": Mississippi River Surge Is a 1-in-500 Year Event
The Mississippi flood happening now is a "Project Flood"—the biggest that could ever occur on the river.
Late Monday night, as we indicated that they might, the Army Corps of Engineers blew up a section of levee on the Mississippi in order to protect the town of Cairo, Illinois from record floods.
The blasts, which were strong enough to register at 3.0 on the Richter scale, breached the Birds Point levee, and sent water cascading over 130,000 acres of Missouri farmland. The decision wasn't without controversy. Or law suit, for that matter. The State of Missouri took the Army Corps decision up to the Supreme Court, which refused to hear it.
When asked whether he would "rather see Cairo or the farmland underwater," Missouri State House Speaker Steve Tilley, told reporters,
Cairo. I've been there, trust me. Cairo...Have you been to Cairo? OK, then you know what I'm saying then.\n
Tim Murphy, who has been to Cairo and surrounding towns has a great piece in Mother Jones that provides some background on the socioeconomic conditions in the area, as well as its heated racial history, which helps explain why folks on the "other" side of the levee were putting their farmland ahead of their neighbors' homes.
In this Wall Street Journal video, you can see the blasts that busted the levees, and the water flowing into Missouri. It also explains why farm owners have to take a healthy bit of blame—the land they bought and farmed was always clearly marked by the Army Corps as being an emergency flood zone.
As Jeff Masters explains, levees on the Lower Mississippi River "are meant to withstand a 'Project Flood'—the type of flood the Army Corps of Engineers believes is the maximum flood that could occur on the river, equivalent to a 1-in-500 year flood." The levees were all built after the Great Flood of 1927—the deadly event that was made famous in the song When the Levee Breaks.
On Sunday night, Army Corps Major General Michael Walsh, the man who ultimately makes flood control decisions, stated (PDF) "The Project Flood is upon us. This is the flood that engineers envisioned following the 1927 flood. It is testing the system like never before."
Here are images of the Mississippi and Ohio Rivers and the "floodway" before and after the breach.
It was the first time in 74 years that the Army Corps blew up a levee on this stretch of the river, and by Major General Walsh's comments (PDF), you can tell it was an agonizing decision:
Everyone I have talked with—from boat operators, to labors, scientist and engineers, and truck drivers have all said the same thing—I never thought I would see the day that the river would reach these levels.\n
We have exceeded the record stage already at Cairo. We are on a course to break records at many points as the crest moves through the system. Sometimes people celebrate with "records"—but not this time. Making this decision is not easy or hard—it's simply grave—because the decision leads to loss of property and livelihood—either in a floodway—or in an area that was not designed to flood.
The destruction of the levee immediately lowered water levels by about a foot and half in Cairo, but only slowed the rise of the Mississippi River below the breach. It's already setting all-time records in the 70-mile stretch below Cairo. Over the next two weeks, this massive surge will snake its way down the rest of the Lower Mississippi, and the National Weather Service is predicting record or near-record flood levels in towns all the way down through Tennessee, Arkansas, Mississippi, and Louisiana. The Army Corps is already discussing "opening up more floodways," or blasting other levees to ease the main surge.
In some regards, a long, slow disaster like this is easier to manage—there probably (hopefully) won't be any deaths, as towns are already being evacuated and there's plenty of advance warning. Contrast that with the horrible tornado outbreak last week, and this "flood" feels like less of an emergency. Let's just hope that the slow, lazy nature of this disaster doesn't make it something that's overlooked by the rest of us.