SCIENCE -- May 4, 2011 at 4:15 PM ET
Mississippi River Valley Flood Areas: Before and After
Despite some relief after the Army Corps of Engineers this week blasted holes into a Missouri levee to draw down the Mississippi and Ohio rivers, flooding fears continue flowing south. Parts of southeastern Missouri, Kentucky, Arkansas, Mississippi and Louisiana are also in danger, and water is rising rapidly in Memphis, where many residents have been told to evacuate.
"Any place south of St. Louis on the lower Mississippi is going to be at some level of flood warning through the rest of the week, said Patrick Slattery, a National Weather Service spokesman.
The Associated Press reports that the Army Corps of engineer is weighing "whether to purposely inundate more land with water."
Like the New Madrid-Birds Point floodway, which is designed to serve as a relief valve during times of flood danger, the 58-year-old Morganza floodway in Central Louisiana and the Bonnet Carre floodway north of New Orleans serve a similar purpose. The U.S. government is considering breaches of both.
A levee failure last week inundated the city of Olive Branch, Ill., and residents in the riverside Brookport, Ill., are "highly concerned about whether their levee is going to make it or not," said Nicholas Pinter, a professor of geology at Southern Illinois University. Water in Memphis is expected to reach flood levels by Friday if rains continue.
Even Cairo is not out of the woods. "We continue to worry about Cairo," Pinter said. "The levees are heavily saturated and we hope that the breach is not too late."
Extended, heavy rains have battered Southern Illinois, Southwest Indiana, Western Kentucky and Southeast Missouri. "The ground there has gotten so saturated by heavy rains, it simply can't absorb anything else," Slattery said. "Any amount of rain is going to turn into instant runoff. It's not that they haven't seen this amount of water before, they haven't seen this amount of water over and over again."
The Ohio River in this area sends more water into the Mississippi than other tributaries, raising the flood risk. Cairo sits right where the Ohio and Mississippi converge.
In threatened cities, residents are evacuating from low lying areas and people are feverishly sandbagging and examining the levees for weak spots and potential problems, said Pinter, who has been sandbagging locally himself in Carbondale, Ill. Yesterday, he said, he saw the sun for the first time in two weeks.
"It was unreal," he said. "We were pretty much in the epicenter of where all that precipitation was."