In the past two decades, formerly simple flood protection has developed into complex flood risk management. Expert’s and public’s focus of this evolution is specifically relevant to the flood events in rivers. This development was triggered in Germany by the flood incidents at Rhine (1993 and 1995), Oder (1997), and Elbe (2002 and 2013). Although there is still a great need for action in the field of flood risk management, nowadays the main focus is the fight against floods. The focus is progressively moving towards heavy rainfall and flash floods.
Heavy rainfalls and resulting flash floods can potentially hit any region and are independent of the location to larger watercourses. In recent years heavy precipitation events hit cities like Dortmund (2008), Münster (2014) and Aachen (2018). But also internationally, heavy rainfalls, such as for example the cyclone Idai in Mozambique, Zimbabwe, and Malawi (2019), flooded entire areas of the countries with heavy precipitation.
The most crucial issue heavy precipitation causes is that at the point of impact everyone is endangered and even small thunderstorm cells can lead to severe local floods with high damages. Thus, classic flood protection concepts cannot simply be transferred to protection against heavy precipitation events. Climate models point to a stronger trend for extreme events. For the future, this might lead to an increased frequency and intensity of heavy rainfall events resulting in high damage.