However, the risk of high water and flooding is tending to increase. This can be caused by melting snow or intense rainfall, particularly in special weather conditions, which lead to a large amount of water in surface waters.

Flood events on streams and rivers differ significantly in terms of their origin and their respective reaction times for the affected residents: on streams, sudden flooding can be triggered by short periods of heavy rainfall, such as summer thunderstorms. This is especially true if the streams have small catchment areas and are located in steep valleys - as is often the case in Wiesbaden. A pronounced flood on the Rhine and Main, on the other hand, is more likely to occur in large-scale weather conditions: intense continuous rainfall lasting several days in the water catchment areas or snowmelt after snowy winters herald possible flooding days in advance. If the water profiles can no longer contain the flowing water volumes, the water overflows its banks, can enter buildings and cause damage.

The severity of a flood depends on the amount of water that accumulates, which in turn depends on the intensity of precipitation and other current conditions: Frozen or dried-out soil, for example, absorbs little rainwater and more water flows off these surfaces.

Without suitable protective measures, areas, buildings and objects can be severely damaged. On the one hand, preventive flood protection means influencing flood events and their effects through municipal measures. On the other hand, it also includes the obligation to take precautions oneself, with which owners and residents can prevent or minimize damage.