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.

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. 


Gefährdungskarte Oberflächenabfluss Schweiz - Technischer Bericht (PDF, 6 MB, 26.06.2018)Im Auftrag des BAFU, des Schweizerischen Versicherungsverbandes SVV und der Vereinigung Kantonaler Gebäudeversicherungen VKG


Additional information

Last modification 11.01.2024

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