S&T Snapshots - Infrastructure & Geophysical

When the Levee Breaks

(June 2007) A hard rain’s a-gonna fall, Dylan sang. But when rain and storm surges fall on lands protected by weak levees, this means trouble … big trouble. Hurricanes Katrina and Rita were devastating reminders of this frightening fact. How then can we limit trouble when a levee breaches or, better yet, prevent such a break from ever happening again?

“Any solution will be difficult and challenging,” says Wil Laska, who manages the Levee Strengthening and Damage Mitigation Project at the S&T Directorate. “But first, we’ve got to ensure that all the levees in the United States are solid, built correctly and well. We also have to make sure that all repairs are attended to on a rigorously timed basis. No ifs, ands, or buts.”

The levee project is a comprehensive one, spanning four years and operating in three phases. In the first phase, researchers will identify potential technologies and procedures that can rapidly and affordably indicate problem locations along a levee, strengthen these existing areas, provide innovative designs for new levees, and repair any breaches. Subsequent phases will test and demonstrate the technologies and procedures. For instance, the U.S. Army Engineer Research and Development Center has developed the Levee Condition Assessment Technology, or LevCAT, which combines geophysical instrumentation with airborne and ground-based research to essentially “see” weak soil under levees.

When considering levee systems, however, there’s another issue at play. River basins, marshes, deltas, savannahs, and other natural buffer zones all protect us from dangerous storm surges. These are often eroding away by the day.

Laska is taking on this problem too. The project also aims to develop approaches and technologies that will duplicate the effect of marshland and reduce the strength of surges. Solutions being considered include inflatable and drop-in structures that last just long enough to prevent severe damage, fast-growing vegetation to rapidly imitate the effect of marshlands in lowering tides, and ways to reroute flood waters and flood-proof critical infrastructure.

Laska is part of a small group of experts focused on S&T Directorate projects called Homeland Innovative Prototypical Solutions, or HIPS. These projects are designed to deliver prototype-level demonstrations of potential game-changing technologies in two to five years. Yes, they come with a moderate-to-high risk of failure, but they can also yield a high payoff if successful.

“All of these goals are enormously ambitious, but that’s the nature of the work,” he says. “Right now, we’re looking at just about any decent idea.”