Saxony hazard warning map (Atlas of the flood hazard in Saxony)

The hazard warning map consists of two map parts, a damage potential map, which shows the possible damage in the event of an extreme flood and a flood map, on which, in addition to the flood areas of different flood events, the intensity based on water depth and specific outflow for the extreme flood is reproduced. Based on the data available from the flood protection concepts, the following flood events were considered: “HQ20 (20-year Flood)” HQ100 " Extreme event (EHQ) significantly larger HQ100, at least the highest known comparable event, in its extent and intensity, but generally = HQ300 (300-year floods). Due to the various flooding processes and thus damage processes, a distinction was made between flat valley areas (slide-free, mostly non-run-changing flooding) and steep areas (dynamic flooding with sliding transport, erosion and expected change of course). Since at the steep sections of the water the flood depth can only indirectly give a statement about the intensity and thus about danger, the flow velocity on the forelands has also been determined. The product of flood depth and flow velocity is determined and represented as a specific drain (outflow per metre of water width). Furthermore, not all three flood events could be viewed and depicted on the waters. The flood areas were calculated without taking into account the effects of existing flood protection devices, such as dams, dikes or polders. The intensities and extensions shown represent an enveloping of all possible flood scenarios, i.e. not all surfaces shown are affected in the same event. This also applies to failures of protective devices. ...