Surface runoff risk map
The map shows where potential risk from surface runoff exists. It covers the whole of Switzerland, both developed and undeveloped regions, and is publicly accessible online.
Surface runoff flood risk areas
Web-GIS des BAFU - Full screen version of the map and other layers concerning natural hazards
The flood risk areas shown on the surface runoff risk map were mapped nationwide for the whole of Switzerland using a standardised method. They are derived from scientifically based modelling, though without a plausibility check at the location. The surface runoff risk map gives a general overview and identifies those areas which could potentially be affected by rare to very rare events. The estimated return period is over 100 years, signifying that in a long term context this type of event occurs less than once in a hundred years on average. The possibility of surface runoff occurring in areas shown as unaffected on the map cannot be excluded. A local plausibility check is required for planning of actual protection measures.
Areas affected by flooding from streams, rivers and lakes do not appear on the map and protection structures, underpasses or culverts through railway embankments, for example, are ignored. The map has no legal force.
Publication Rainwater in Urban Areas
As a result of climate change, heavy rainfall is becoming more intense and frequent. In urban areas, where infill development is leading to increased soil sealing in many places, the risk of flooding caused by surface runoff after heavy rain is therefore rising. In climate-resilient and risk-based urban development, the sustainable management of rainwater as a resource is becoming increasingly important.
Below you will find the publication on rainwater in urban areas: