Surface run-off map
Link to the surface run-off map of Switzerland for the Federal Office for the Environment FOEN.
Up to 50% of the damage caused by floods is caused by surface runoff. Surface runoff occurs when the soil cannot absorb precipitation because it is too dry, frozen or already saturated, and the water runs off the surface. Around 70% of all buildings in Switzerland are at risk from surface water, with an increased risk for properties on/below slopes or in hollows.