Nature-Based Flood Defenses
Over 1400 hydro-engineers from all of the world have gathered at the 36th edition of the annual world congress of the International Association for Hydro-Environment Engineering and Research (IAHR) in the Hague, the Netherlands (June 28 – July 3).
Bregje van Wesenbeeck from Deltares was a keynote speaker on the opening day of the IAHR world congress.
In her presentation, Van Wesenbeeck disclosed that much research is currently taking place to enable engineers to construct flood defenses that use nature-based solutions in combination with hard flood defense structures.
She gave several examples of severe flood events in the world, where there has been no immediate response to build higher levees.
As a Dutch expert on flood defenses this surprised her in a way, she admitted in her keynote. On the other hand she is an expert on nature-based flood risk mitigation at Deltares, so she is very much aware of the enormous potential of soft flood defenses such as mangrove forests, tidal marches, sand dunes and oyster reefs.
“Are nature-based flood defenses a panacea or an illusion?” That was the central question in Van Wesenbeeck’s inspiring presentation on this new phenomena.
She pointed out that these kind of flood defences are no panacea. Mainly because they require much space which in many cases, especially in urbanized areas, is not available.
Van Wesenbeeck warned that little is known about the behavior of nature-based defense under extreme circumstances: “We may create a false sense of security as we simply know too little about their behavior under extreme circumstances.”