⚠️This is the first operational version of the handbook, but it is still a work in progress and will be heavily updated during 2024!⚠️



Floods are broadly defined as an overflow of a large amount of water over a land that is normally dry. Changes in flood frequency and intensity played a crucial role in maintaining ecological balance. In the CLIMAAX risk workflows we are focusing on riverine and coastal floods. The risk emerging from types of floods result from a combination of natural factors (e.g. hydrological processes), human activities (e.g. construction of structural measures, or land-use changes), and climate dynamics.

Riverine floods occur when rivers overflow their banks, inundating adjacent areas with water. The main physical drivers of riverine flooding include heavy rainfall, snowmelt, and storms, which can lead to an excessive inflow of river flow. In addition, human activities such as deforestation, urbanization, and land management can influence hydrological processes thus leading to changes in intensity and frequency of riverine floods. Riverine floods can have severe impacts on agricultural lands, displacement of populations, and damage to infrastructure.

Coastal floods result from the intrusion of seawater onto coastal lands. They can be triggered by storms, high tides, or tsunamis, and are often influenced by sea level rise due to climate change. Coastal areas are particularly vulnerable to these events, with low-lying regions experiencing the most significant impacts. Coastal floods have severe impacts on erosion, salinization of freshwater resources, and the loss of valuable habitats.

The proper assessment of flood risk is crucial for developing effective mitigation and adaptation strategies under future climate change scenarios.