5 years after Katrina, satellites monitor flood defenses

The disaster that hit New Orleans in the wake of Hurricane Katrina was caused by poor flood defenses. Some levees were too low, others lacked the necessary robustness and still others had been built on marshy soil. To make matters worse, no-one knew the exact status of the levees. What lessons have we learned five years after Katrina? Dutch engineering company Hansje Brinker, spinoff from Delft University of Technology operates a system that systematically monitors the status of levees by satellite.

Radar signals from European satellites rebound on the levee surface and are picked up again in space. These signals are measured every few weeks to check out the condition of the levees and to register any changes on a scale of millimetres.

Monitoring for defects

After the disaster in New Orleans it emerged that deformation had occurred years ago at many of the locations where the levees had failed, sometimes at a rate of several centimetres a year. So, there were already signs of defects.

In the Netherlands an experimental levee revealed that flood defences undergo small deformations before they give way. So, deformation-monitoring is an effective means of detecting weak areas.

Hansje Brinker

This method, which systematically monitors flood defences in the Netherlands with pinpoint precision, was developed by Delft engineering agency Hansje Brinker - named after the world-famous youth who averted a flood by spotting a hole in a levee. Measurements are performed every week, for select levees around the world.

More information:
www.hansjebrinker.com/nieuws/new-orleans/

Provided by Delft University of Technology