Flood (groundwater)

In general, groundwater levels rise if the amount of rainfall exceeds the evaporation, and (slowly) fall again afterwards. In the Netherlands, groundwater levels also change through active management. During short, heavy rainfall events or prolonged wet periods, groundwater levels can rise to an extreme level and stay high for a longer period. Depending on the geohydrological characteristics of a landscape, groundwater levels can change fast or slow, making it a complex factor to predict and manage*. As explained in the Climate Adaptation Knowledge Portal’s knowledge dossier, groundwater flood may occur also with a temporal lag after coastal & fluvial flood events.

Figure shows the different types of flooding in the Netherlands.
The image displays the different types of flooding in the Netherlands. (A) Flooding of unprotected areas along the main water system. (B) Flooding of protected areas along the main water system. (C) Flooding of protected areas along the regional water system. (D) Flooding of unprotected areas from the regional water system. (E) Pluvial flooding. (F) Groundwater flooding. Source: adapted from Klopstra & Kok and Ministry of Infrastructure and Water Management (PDF).

In extreme situations, the groundwater level can rise above the surface level height and create puddles. It is then possible for water to enter buildings through doorways and openings in the façade, in the same way as with pluvial flooding.

Generally, groundwater flooding can last a relatively long period of time and potentially cause damage to agriculture, infrastructure and urban areas.

*This type of flooding can also be caused by engineering or water management flaws. This portal, however, does not focus on these causes.