The spillways, however, were built on much more weathered rock that easily crumbled this winter, Rogers said.
Ex-governor's ambitions paved way to dam crisis, records say →
"It's like combat: Defend your perimeter. Where are my weakest points on my perimeter? Water will find the weakest point," said J. David Rogers, an engineer and levee expert at the Missouri University of Science and Technology in Rolla, Mo.
New Orleans levee upgrades nearly ready →