100årsöversvämning

100årsöversvämning, which translates to "100-year flood" in English, is a term used in hydrology and flood risk management to describe a flood event that has a 1% probability of occurring in any given year. This means that, on average, such a flood is expected to happen once every 100 years. It is important to understand that a 100-year flood does not mean a flood of this magnitude will occur precisely every 100 years. It is a statistical probability, and multiple 100-year floods could theoretically occur within a shorter timeframe, or a much longer period could pass without one.

The concept of a 100-year flood is a common benchmark used in many countries for planning, building codes, and insurance purposes. Infrastructure like bridges, dams, and flood defenses are often designed to withstand or mitigate the impact of such events. However, the term can sometimes be misunderstood by the public, leading to a false sense of security or a belief that the event is guaranteed to happen only once a century.

Climate change and changes in land use can alter the frequency and intensity of floods, potentially making historical flood statistics less reliable for predicting future events. Therefore, while the 100-year flood concept remains a useful tool, it is increasingly being supplemented by more sophisticated risk assessments that account for these dynamic factors.