Heavy rain hazard maps define zones at risk for flooding. On the one hand, they form an important basis for planning preventive and emergency measures in the event of sudden or persistent heavy rainfall. On the other hand, they help to inform and sensitize citizens to possible hazards in case of extreme weather events. Together with VRVis, Hamburg Wasser is compiling a heavy rainfall hazard map for the entire city on behalf of the Federal Ministry for the Environment, Climate, Energy and Agriculture (BUKEA) and has now released the first results online for the regions of Tarpenbek, Wandse/Osterbek, the areas of the Süderelberaum (including Harburg) and the area of Altona.
Hydrodynamic simulations considering many variables
Numerous different parameters and data need to be incorporated into heavy rainfall hazard maps. This requires complex hydrodynamic simulations, for which Hamburg Wasser relies on the VRVis software Visdom. This application delivers visualizations of flood risk for very large areas within a very short time and manages to consider complex water structures.
The heavy rain hazard map for Hamburg shows maximum water levels and flow rates that can potentially be expected across three different scenarios. The modelling calculations include the runoff from the public sewer system as well as surface runoff. Infiltration of water into the ground and temporary storage of precipitation on plant surfaces (interception) are also included. The model for Hamburg´s heavy rainfall hazard map is regularly updated and constantly optimized.
Facilitating planning and prevention
The heavy rainfall hazard map for the six other regions of the city will gradually be completed and published online. All citizens of Hamburg thus have the opportunity to verify easily whether or to what extent their home or property could be affected by flooding. 3D visualizations make a significant contribution to communicating threats due to heavy rain in a straightforward manner. This facilitates measures of individual precaution. At the same time, the model of the map is an essential basis for the design and evaluation of water-sensitive protection measures, which is important for sustainable urban development and planning.
Detailed project information
Vienna, October 6 2023