Municipal flow path maps provide an overview of possible paths that water could take in the event of heavy rainfall. The direction of rainwater runoff is shown by flow arrows, but the flow path maps do not show possible flooding depths. Buildings along flow paths are graded in different colors depending on the distance: red (five meter distance), orange (ten meter distance), yellow (15 meter distance) and white (other buildings). In addition, different land uses (arable land cultivated parallel to the slope; grassland and garden land) are shown for graded slopes.

The data basis for the flow path maps is a digital terrain model (five-square-meter grid and one-square-meter grid, building footprints and agricultural land (ATKIS and ALKIS data). If buildings or land use have changed since the time of the data basis, this must be taken into account when interpreting the maps. Flow path maps are particularly useful in rural areas with large differences in terrain. Flow path maps are less meaningful in areas with very gentle slopes. In urban areas, the direction of flow is often greatly altered by buildings, walls, culverts or roads, so that the flow path map can only be used to a limited extent for these areas.

After the flow path maps for rural areas had already been tested in four Hessian pilot municipalities, the state capital of Wiesbaden was selected as a further pilot project in the urban area. In cooperation between the Hessian State Agency for Nature Conservation, Environment and Geology (HLNUG) - Hesse Climate Change Center and the Rhine-Main University of Applied Sciences (Heavy Rainfall and Flash Floods working group at the Department of Architecture and Civil Engineering), flow path maps were calculated for most of the urban area of the state capital of Wiesbaden. As the districts of Kostheim, Kastel and Breckenheim and the east of Delkenheim lie outside the calculation limits, no flow path maps are available for these areas. However, they were taken into account in the subsequent creation of the heavy rain hazard maps. The city-wide flow path map can be accessed via the geoportal of the city of Wiesbaden - see link at the bottom of the page. All existing flow path maps can also be downloaded at the bottom of the page. The assignment of the map sections follows the numbering in the overview map.

Typical questions that may arise from the presentation of some maps and the answers are linked under further information.