Integrated Apporach for Assessing Climate Change Impacts on a Regional Chalky Acquifer in Belgium

An integrated hydrological model was developed in order to study the potential effects of climate on groundwater resources. This model considers most hydrological processes in a physically consistent way. More particularly, groundwater flows are modelled using a spatially distributed finite element approach. The river-aquifer interactions are explicity taken into account in the model, as well as the spatial heterogeneity of the chalk geology characteristics. After a detailed caliberation on the last 30 years and validation on recent periods, quantitative interpretations can be drawn from the groundwater model results. Considering interpretations can be drawn from the groundwater model results. Considering IPCC climate change scenarios, it appears that, on a multi-annual basis, most tested scenarios predict a decreasing trend in groundwater levels in the Geer basin. These first results indicate that groundwater deficits may be expected in the future in Belgium. Moreover, at this stage of the study, this trend is computed for a very “optimistic” scenario, negliecting all other pressure changes on the groundwater resources (Le. no change in land use and in pumping conditions).