Assumptions & limitations for groundwater floods

Assessing groundwater flood risks requires understanding both the underlying assumptions and limitations of the available datasets:

• The probability map is based on national groundwater level change models, resulting in a coarse spatial resolution.
• Groundwater flooding depends on local conditions, such as the presence of drainage systems, the sensitivity of buildings, the condition of sewage systems, underground obstacles, and tree presence. Such conditions are not reflected in the map, nor are preventive measures.
• The dataset primarily focuses on built-up areas, making it less suitable for non-built-up spaces.
• The Delta scenario ‘Warm’ was used to estimate changes in groundwater flooding probability. This scenario combines the KNMI’14 WH scenario with low economic growth, leading to the largest increase in the highest average groundwater level. It assumes wet winters, high summer rainfall intensity, moderate groundwater extraction, and includes land subsidence.