FloodsHow Do We Prepare for Extreme Flooding?

By Martin Kuebler and Tim Schauenberg

Published 21 July 2021

As the floodwaters recede following the devastating deluge in western Europe, survivors have begun the long, difficult process of cleaning up and rebuilding. But what can be done to reduce future risks?

Extreme flooding in western Germany and neighboring Belgium has killed nearly 200 people and left dozens still missing. With recovery operations still underway, talk has now turned to how communities can prepare for the extreme weather events expected to become more likely with climate change.

On a visit to the disaster area, Armin Laschet, the conservative state premier of the hard-hit German state of North Rhine-Westphalia, said more needed to be done to protect people from the effects of the climate crisis. “We will be faced with such events over and over, and that means we need to speed up climate protection measures, on European, federal and global levels,” he said.

But, for experts like Lamia Messari-Becker, a civil engineering professor focused on sustainable building and design at the University of Siegen, now is not the time to talk about vague climate change adaptation.

Now is the time for engineers,” she told DW. “We need real help, ideas, solutions. We can’t rely on the normal processes or procedures now. We are dealing with an exceptional situation.”

The German government has already announced a financial aid package to help support the huge task of rebuilding private properties and public infrastructure such as roads, highways, and communication and power networks.

Building Back Better
When it comes to adapting buildings to withstand floodwaters, Messari-Becker drew parallels with earthquake-resistant architecture. In such buildings, the depth of the foundation, structural design and building materials are specifically chosen to be able to handle extreme flooding. Many collapsed homes in the worst-affected regions were hundreds of years old, built around a wood frame not able to withstand masses of water.

That’s exactly how we have to operate here, when we’re dealing with such amounts of water,” she said. “We need to reinforce basements so that they can also fill up with water and people can quickly get to safety. It’s also about the reinforcing measures needed for outer walls, for roofs.”

Boris Lehmann, a professor in hydraulic engineering at the Technical University of Darmstadt, said measures such as retention valves on sewage connections, which prevent floodwaters from backing up into homes, and waterproofing windows and doors on the lower levels of buildings were also essential.