Flood is the state of a waterbody where the water level or discharge reaches or exceeds a certain threshold value.
Floods in Switzerland
A lot has been done in the area of flood protection in Switzerland, in particular since the mid-19th century. Today, priority is given to ensuring the maintenance of existing flood protection structures. However, the floods of 1987, 1993, 1999, 2000 and 2005 in Switzerland highlighted the limits of technical flood protection measures.
The flood of August 1987 caused damage totalling CHF 800 million; CHF 500 million of these costs arose in the canton of Uri alone.
The material damage caused by the flood of August 2005 totalled around CHF 3 billion – hence the damage caused was significantly higher than by all of the previous natural hazard events systematically recorded since 1972.
Based on the strategy of integrative risk management more measures will be taken in future to limit the damage caused by natural hazard events. For example, hazard potential will be reduced through spatial-planning measures, based on which areas at risk from natural hazard will not be subject to development and open space will be created or conserved for watercourses and water bodies. Hazard maps provide the basis for the assessment of the hazard risk that exists in certain areas. If these measures are insufficient, up-to-date technical measures (e.g. channel improvement, water retention measures and the drainage and redirection of flood peaks) will be taken to reduce the hazard potential.