We put science into practice

What role do bridges play during floods? We present our research findings at the “Heavy Rain & Flooding Action Day” organised by the town of Bad Neuenahr-Ahrweiler.

Plakat zum Aktionstag Starkregen Hochwasser am 27.09.2025 von 10 bis 16 Uhr auf Marktplatz Ahrweiler.

Research into the damage caused by the 2021 flood disaster to bridges along the Ahr river is particularly relevant for the Ahr valley. In the flow channel, for example, the effects of log jams caused by floating debris on the water level and flow velocity for different bridge designs were analysed as part of the ‘Climate Adaptation, Flooding, Resilience’ (KAHR) project. 

Zwei Personen stehen vor einem Messestand mit schwarzem Pavillon, Tischen, Monitor und Informationsmaterial.

Heavy Rain & Flooding Action Day: Tanja Nietgen and Dr. Bert Droste-Franke provide information to visitors at our stand. 

Versuchshalle des Lehrstuhls und Instituts für Wasserbau und Wasserwirtschaft der RWTH Aachen mit großem Wasserbecken und Apparaturen zur Durchführung von Experimenten und wasserbaulichen Modellversuchen.

Test hall of the Chair and Institute of Hydraulic Engineering and Water Resources Management at RWTH Aachen University.

RWTH Aachen/IWW

Strömungskanal in der Versuchshalle des Instituts für Wasserbau und Wasserwirtschaft der RWTH Aachen mit Brückenmodell und Wasserfluss unter der Brücke.

Flow channel in the experimental hall of the Institute of Hydraulic Engineering and Water Resources Management at RWTH Aachen University.

RWTH Aachen/IWW

The findings of our project partner, the Institute of Hydraulic Engineering and Water Resources Management (IWW) at RWTH Aachen University, show that the following factors, among others, are decisive for flood-adapted construction: the height of the bridge, the size of the discharge cross-section, its span and its foundations. The higher and larger the bridge, the less damage is to be expected. Bridges with shallow foundations were more severely damaged by the floodwaters of the Ahr in 2021. 

How does science work? With a film by the IWW, we provided exciting insights into research practice at the market square in Ahrweiler. The bridge model exhibited at our stand also gave a vivid impression. 

After the flood disaster: opportunities for change 

The new practical guide for local authorities met with great interest among the population. Among other things, the brochure provides recommendations for reconstruction, flood protection and strengthening the resilience of societies. 

Our interactive model cube ‘SmartEnergyCity’ was also on display. Visitors were able to test the possibilities of a smart, sustainable energy supply for themselves by switching photovoltaic systems, wind power, electric cars, etc. on and off. A simulation of typical weeks in three seasons (summer, transition period, winter) shows the possibilities and limitations of the supply with the selected combination. 

Are you interested in the practical guide „Nach der Flutkatastrophe: Chance für Veränderungen“ (in German)? 

Download the brochure 

SWR is showing a film about the action day: Lessons from the Ahr flood – how to protect your house from heavy rain and flooding. 

To the film (2 min)

Contact at IQIB

Dr. Bert Droste-Franke