While many of the potential consequences of climate change have already been studied, little research has been carried out up until now on groundwater sources. Civil engineer and geologist, Pascal Goderniaux, published a methodology to estimate the impact of climate change on groundwater reserves in the Journal of Hydrology. The application he proposes concerns the Hesbaye region or the Geer basin (1). The proposed methodology can be applied anywhere in the world.

“There are an increasing number of studies on the effects of climate change on surface water”, explains Pascal Goderniaux, a PhD student and FNRS fellow researcher in ULg’s Hydrology and Geology of the Environment team (ArGEnCo department and AQUAPOLE Research Centre). But the majority of these studies neglect, or over-simplify, the behaviour of groundwater, even though it provides the biggest supply of drinking water worldwide. In Wallonia, 80 % of tap water comes from an underground source. In Liège, the majority of drinking water consumed comes from the Hesbaye aquifer, where 30 million cubic metres of water are extracted every year thanks to an important network of galleries and wells!”

The Geer basin, to which the young researcher from Liège applied his methodology within the framework of his doctoral thesis, covers approximately 465 km². The source of this tributary of the Meuse is close to Waremme and joins the Meuse just after the Dutch border, beyond Kanne. The region’s groundwater is stored in the thick layers of chalk formations dating from the Cretaceous period, in the pores and fractures of the rock. These chalk formations lie on a relatively impermeable layer of clay. Above the chalk formations, a thick layer of silt acts as a buffer and filter.

(1) Goderniaux, P ., Brouyere, S., Fowler, H.J., Blekinsop, S., Therrie,n, R., Orban, P., Dassargues, A., Large scale surface-subsurface hydrological model to assess climate change impacts on groundwater reserves, Journal of Hydrology (2009), doi: 10.1016/j.jhydrol.2009.04.017