KAHR - Scientific Monitoring of the Reconstruction Processes after the Flood Disaster in Rhineland-Palatinate and North Rhine-WestphaliaCopyright: © Peter Winandy
Flood protection is not a new field of research. But the catastrophic floods in Rhineland-Palatinate and North Rhine-Westphalia last year have (unfortunately) placed the topic on the agenda once again. In the collaborative project KAHR: Climate, Adaptation, Flood, Resilience, various German institutions are seeking to provide scientific support for post-flood reconstruction and to identify the causes of the flooding. "Bridges have played a crucial role," explains Professor Holger Schüttrumpf from the RWTH Institute of Hydraulic Engineering and Water Resources Management, IWW for short, which is responsible for analyzing the flooding events from a water management perspective. “At bridges, the river is narrowed. If these bridges are built too low and have many piers, they act like a sieve in which everything from tree trunks to vehicles to oil tanks gets caught up.” This blockage at bridge piers leads to a rapid rise in water level upstream of the obstruction.
Schüttrumpf's team took a close look at all of the 114 bridges crossing the river Ahr. “On average, there is a bridge every 700 meters; in the cities, the average distance between bridges is only 150 meters,” says Schüttrumpf. “According to our calculations, this raises the water level of the Ahr by 2 to 2.5 meters – almost the height of a story.” Rebuilding bridges or constructing new ones could provide relief for the river; another option would be to install flood retention basins at strategic locations – for example, at the foot of vineyards from which masses of water rush down after heavy rainfall.
In order to convince both the population and policymakers of the importance of such construction measures, the knowledge gained in the project will be widely disseminated via public workshops and panel discussions. "Without political will, nothing much will change – and people might find themselves at the mercy of the next flooding disaster."