Storm flood
A storm flood is an unusually high rise in water levels on coastlines and tidal rivers that exceeds the normal tidal cycle. Storm floods can cause extreme flooding in coastal regions, sometimes resulting in damage to buildings, infrastructure, or dikes. They can cause material damage to boats and ships in harbors and contribute to the erosion of beaches. In estuaries and bays, seawater can advance inland during storm flood events and salinize the groundwater reservoir, which can have negative consequences for the water supply.
To determine the storm surge risk, wind speeds at sea, coastal geometry, and tidal flow are taken into account. In general, our analyses assume that all areas that are lower than 10 m above sea level and at the same time closer than 30 km to the coast are potentially at risk of storm floods.
Fluvial flooding
Flooding refers to the rise in water levels of rivers or streams due to heavy rainfall, often in combination with snowmelt. Fluvial flooding can inundate surrounding areas and cause damage to infrastructure, buildings, vehicles, and agricultural land. Flooding, for example in urban areas, can release pollutants that contaminate water bodies, groundwater, and soil.
The flood model integrated in K.A.R.L.® determines the risk of fluvial flooding. The model first assesses the flooding potential by analyzing the terrain profile with the digital elevation model integrated in K.A.R.L.®. In a second step, climatological, hydrological, and geographical factors are used to calculate maximum water levels and return periods.