Each municipality is responsible for itself
Basically, each municipality has to manage the risk of flooding itself and there are often negligence due to a lack of regulation. For example, there is no obligation for the municipalities to look at the flood maps before starting a new construction project. At this point it should even become obligatory for the municipalities to look at the natural hazard maps in order to prevent all natural disasters as best as possible. The flood control centers of the federal states provide the flood maps free of charge. Every municipality can check online how great the flood risk is in the immediate vicinity of a building area.
The risk-based approach according to the Flood Risk Management Directive applies across Europe: You look at the damage potential and look back at the largest flood event of the past few years – 100 or even 500 years. On this basis, the necessary degree of protection is defined with arguments of economic efficiency, which is definitely expedient.
Basic protection is too low in Germany
Germany is transposing the FD into national law with the Water Resources Act (WHG). The risks associated with flooding are not regulated in the Major Accidents Ordinance. On the Rhine in Baden-Württemberg, protection class 4 (very high) applies to objects with special risks such as conventional power plants or refineries with national importance. Flood protection is assessed and set up as an individual case for these facilities.
In Switzerland, the degree of protection for special risk objects is generally higher: HQ 300 plus protection based on an individual risk assessment. In federal Germany, the increase in the specified degree of protection by the federal states is not uniformly regulated. The WHG is supplemented individually by the federal states. The federal states implement flood protection.
Conclusion: Work more carefully when it comes to flood protection
The correct procedure for flood prevention is complex, but protection in the event of a disaster is necessary. In the case of special risk properties in particular, the engineering offices and experts from the offices of the federal states should take a closer look and increase flood protection in order to also minimize consequential damage. With the one-size-fits-all approach to risk assessment, the details in the respective regions are not given enough attention in Germany.
guest post by Prof. Dr.-Ing. Timo Heinisch, Professor of Civil Engineering at the IU International University