Compared with other types of infrastructure, the nation's levees, within and outside federal jurisdiction, don't fare well. They earned a D-minus for overall condition from the American Society of Civil Engineers in its latest report card in 2009, ranking behind dams, bridges, rails and eight other categories.
The condition of flood control systems came into dramatic focus in August 2005 when Hurricane Katrina's rain and storm surge toppled levees in New Orleans and tore up the Gulf Coast. It left 1,800 people dead and was the costliest storm in U.S. history with damage estimated at $108 billion.
Afterward, Congress told the Corps to catalog federally overseen levees, many of which it built and handed over to municipalities to run and maintain. The Corps has spent more than $140 million on inspections and developing the inventory.
As of Jan. 10, the agency had rated 1,451 or 58 percent, of them. Of those, 326 were unacceptable, 1,004 were minimally acceptable with deficiencies that need correcting, and 121 were acceptable.
In the AP's examination, among the most widespread issues were:
— Design or construction flaws.
Some levees had inadequate "freeboard" — extra height to prevent overflow, which can weaken the landward slope of the levee. For example, the Corps found there was not enough height in a levee along a 20-mile stretch of Mississippi's Yazoo River system, which came close to being overtopped in 2011 during historic flooding of the Mississippi River valley.
— Inadequate or crumbling infrastructure.
Many pipes built into levees to drain storm water were made of metal that has rusted. And pumping systems are giving out. In Brookport, inspectors found inoperable pumps and deteriorating pipes in its 6-mile-long earthen levee. Their report said a gaping hole just outside town has put the structure in "critical condition."
— Failure to control vegetation and invasive animals.