Hazard and risk assessment

Areas without visible streams lack sufficient capacities for runoff potentials as described above. Thus there exists no knowledge about flow paths, flow characteristics (high flow velocities), potential retention in subways, underground parking, tunnels etc. and arising hazards. Further hazards emerge from drifted objects such as chattels, cars, trees etc.

Following issues will be investigated:

• Detection and definition of separate threats to citizens, industry and relief units due to extreme runoff in differently structured urban areas with different landuse
• At which runoff conditions are streets and footpaths still accessible?
• How evolve hazard areas depending on the course of event?
• Can hazards be classified in order to present (picture, display) them in a map?
• Which consequences can be derived from for a better precaution and disaster response in terms of buildings laws and urban planning?

Analysis

Hazards and risks caused by flash floods in urban areas are to be described and analysed. Main impacts of parameters (such as flow velocity and flow depth, backwater residence time, wave rising gradient, impact impulse and impact direction) will be tested and classified in order to define different hazard types and levels. Sophisticated schemes for hazard and risk maps will be developed depending on urban area structures. Such maps may help to point out threats to the public and be a base for an attendance and resource availability information and helpful for relief units. Furthermore interactions and patterns of behaviour of all relevant actors will be analysed in the context of all existing institutions and responsibilities (ex-post-analysis).