More on Blowing Up Levees

The Army Corps does this more often than I thought:

Maj. Gen. Michael Walsh — the man ultimately responsible for the decision to go through with the plan- has indicated that he may not stop there if blasting open the levee doesn't do the trick. In recent days, Walsh has said he might also make use of other downstream "floodways" — basins surrounded by levees that can intentionally be blown open to divert floodwaters.

Among those that could be tapped are the 58-year-old Morganza floodway near Morgan City, La., and the Bonnet Carre floodway about 30 miles north of New Orleans. The Morganza has been pressed into service just once, in 1973. The Bonnet Carre, which was christened in 1932 has been opened up nine times since 1937, the most recent in 2008.

"Making this decision is not easy or hard," Walsh said. "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."

Officials in Louisiana and Mississippi are warning that the river could bring a surge of water unseen since the Great Mississippi Flood of 1927.

The corps has said about 241 miles of levees along the Mississippi River between Cape Girardeau, Mo., and the Gulf of Mexico need to be made taller or strengthened.


George Sills, a former Army Corps engineer and levee expert in Vicksburg, Miss., said the volume of water moving down the river would test the levee system south of Memphis into Louisiana.

"It's been a long time since we've seen a major flood down the Mississippi River," Sills said. "This is the highest river in Vicksburg, Miss., since 1927. There will be water coming by here that most people have never seen in their lifetime."

The 1927 flood is featured in the book Rising Tide: The Great Mississippi Flood of 1927 and How it Changed America.  It features a lot of history of New Orleans and Mardi Gras, a lot about hydraulics and hydrology of the Mississippi River, a lot about the history of the Army Corps and levees, and a good bit about race relations in the Mississippi Delta.  Herbert Hoover makes an appearance, and a levee is blown up to save New Orleans.  It is a great book, and I highly recommend it.