Withstanding Extreme Weather Conditions

Jochen Kurrle, torrential rain Manager, Drees & Sommer

With increasingly regularity storms, torrential rain, floods, snow, hail and even heatwaves are causing immense damage in Germany and in other countries, making it more and more important for towns and municipalities throughout Europe to have climate adaptation strategies and suitable prevention measures in place. Demand from the majority of clients is especially high for solutions that provide their residents with protection against torrential rain and flooding, and which make sensible use of water as a resource.

As a result of climate change, meteorologists expect extreme water events to occur more frequently and with greater severity in the years ahead. Last Thursday a hurricane-force storm – called Friederike by the Institute of Meteorology at Freie Universität Berlin – caused chaos, power outages, train cancelations and enormous damage in the German federal state of North Rhine-Westphalia. Friederike had barely taken her leave when flooding returned. ‘Weather phenomena such as storms, torrential rain and heatwaves are the initial consequences of impending climate change. It is therefore becoming all the more important for social stakeholders in the fields of politics, economics and science to encourage people involved in urban development to focus on suitable climate adaptation strategies and prevention measures,’ said Gregor Grassl, Senior Project Partner and Head of Green City Development at Drees & Sommer SE.

Role of torrential rain manager: to minimize the effects of sudden occurrences of massive quantities of water in towns and cities

‘Massive cloudbursts can devastate entire cities. This often leads to flood risks some distance from the event, whose effects can be difficult to calculate. It is therefore important to take measures prior to the occurrence of such events that will minimize the negative effects as much as possible,’ explained Jochen Kurrle, Senior Project Partner at Drees & Sommer SE, whose main focus is the field of torrential rain risk management – a torrential rain manager, so to speak. Important findings are obtained from questions regarding the state of water and drainage systems, mobile and fixed flood protection measures, and whether there are enough retention basins and retention areas to accommodate large quantities of water. How easy it is to reach important services in the event of a catastrophe is another key factor. There is also particular focus on how to carry out construction work in our towns and cities both now and in the future. The findings give rise to an integrated infrastructure system plan which Drees & Sommer then uses as the basis for its project work.

A park when the sun is shining – a water retention area when it is raining

The creation of innovative blue-green infrastructure is key to adapting our cities to the force of nature that is rain water – an infrastructure that combines green spaces, water management and the strategic use of modern technology. This affects central services provided by the public sector: mobility, public spaces, safety and biodiversity. One example can be seen in parks that serve as leisure spaces when the weather is good, and that transform themselves into lakes or canals during cloudbursts. This concept of multi-functional spaces is a natural way to retain large quantities of water. With this single measure, innovative planning can enable the simultaneous provision of flood protection, heat protection, air pollution control, biodiversity and attractive leisure spaces.