by Thorsten Koch
The Federal Office for Civil Protection and Disaster Assistance would like to see risk areas that might be subject to flooding better mapped – with a special focus on smaller rivers. A spokesman announced that there is already data for larger rivers that can be used to create simulations of heavy rain events. This availability of data can be traced back to an EU directive.
In the meantime, several scientists have called for urban planning to concentrate on the need for protection against the effects of climate change. Claudia Kemfert, head of department at the German Institute for Economic Research in Berlin, called for more drainage areas to be designated and investments in flood walls. Germany must be a pioneer in risk prevention in the EU, she emphasized. According to media reports, the chairman of the environmental protection organization BUND in North Rhine-Westphalia, Holger Sticht, criticized the fact that an area of eleven football fields, or eight hectares, are sealed each day when residential areas and traffic areas are created.
Retention and drainage
Drainage areas nationwide are not yet oriented towards the conditions of climate change, said an expert from the German Weather Service, Andreas Becker. Canals, for example, are designed in such a way that they can cope with normal amounts of precipitation, but they might fail in the event of heavier precipitation, which used to occur less often than every 20 years. Becker predicts that extreme weather will occur every five years, in the future. This ought to change the relationship between the cost of prevention and high damage. Installing pipes with a higher capacity is too costly. Therefore, Becker, who is also the head of the World Center for Precipitation Climatology, suggests to do calculations as to where the water concentrates during heavy rain and, based on this, to ensure that the water drains off as optimally as possible.
Civil engineer Lamia Messari-Becker from the University of Siegen has called for an adaptation of the infrastructure and better urban planning. Basements have to be strengthened, and bridges are to be raised. Boris Lehmann from the TU Darmstadt called for more controls in building areas which may be in danger of flooding. Lehmann also pointed out that simulations could be used to identify potential damage and weaknesses. The results could be used to preventively improve water flows and retention.
Improved civil protection and construction
The Association of Towns and Municipalities took a slightly different approach. Civil protection should be made more sustainable. In particular, the Federal Office for Civil Protection and Disaster Relief should be strengthened. The extent of heavy rain should in the future be better communicated as part of the early warning than was the case with the recent floods in western Germany. Personal provision should be improved, the association suggested: “It ought to be the right step to do to secure air shafts against the ingress of water or to install backflow valves.” It makes sense to make bridge structures higher than before. Houses could be built in such a way that the two basement floors could be flooded. In addition, correct behavior of people in dangerous situations will be necessary as well as depots with food and essential objects such as emergency power generators where there is a risk.
No constructions in certain areas
Meanwhile, there is a debate as to whether certain buildings should in all cases be rebuilt the way used to be before the disaster which occurred two weeks ago. Thomas Kufen (CDU), deputy chairman of the City Council of North Rhine-Westphalia, emphasized with a view to particular dangers: “It may well be possible that in certain locations, no construction spaces can be re-designated in the future.” In addition, it more floodplains may be needed.
Landscape planner Dietwald Gruehn from the TU Dortmund confirmed this view, saying that in flood-prone areas, new development areas may be weak points. Construction areas would have to be restricted to suitable locations and be able to carry or store water. The infrastructure is particularly at risk, said North Rhine-Westphalia building minister Ina Scharrenbach (CDU). Town halls and fire departments, for example. Changes could possibly be implemented as to critical buildings, provided that nationwide planning law is accelerated. Christian Albert, professor at the Ruhr-Uni Bochum, sees three options: improving technical protection, for example by way of dykes; an adapted mode of settlement; or complete prohibitions for buildings in certain areas. Which option applies will depend depends on local conditions, Albert added.