Hydrogeological research in support of the radioactive waste disposal programme includes both investigations of the groundwater system at regional (Kempen) and local scale and specific site investigations at the reference site at Mol.

We model the groundwater flow and transport to deepen the understanding of the regional groundwater system and to predict values of specific parameters that are used in the safety assessments.

Hydrogeological investigations also support the research on the effects of future climate changes on the groundwater systems that will be the environment of the disposal system.

Research activities

Groundwater monitoring programme

The regional investigation programme consists of two parts, the piezometric network and the borehole investigation programme. The piezometric network consists of more than 60 sites with several multi-piezometers monitoring groundwater levels in 4 regional aquifers covering a large area of north-eastern Belgium. The groundwater levels are monitored monthly, the longest observed period exceeds 25 years.

Position of objects in the SCK•CEN regional piezometric network

Site characterisation

Information obtained from several boreholes drilled during consecutive site investigation campaigns complete the knowledge of the regional and local aquifer systems and the host rock properties. This information includes various types of data measured both in the borehole and on water and rock samples from the boreholes. Sand and clay samples taken from these boreholes are carefully conditioned and stored to prevent their oxidation and consequently used for specific analyses. Investigation objects, such as boreholes and piezometers as well as the analyses results and data obtained are stored in a relational database system linking the geographically referenced objects with the data.

Groundwater modelling

Groundwater models are built to demonstrate our understanding of the groundwater system and to estimate specific parameters needed for performance assessments. Various models have been built at different scales ranging from the regional scale through intermediate scale down to a detailed scale for transport modelling. Main models developed at the regional scale cover the area of whole north-eastern Belgium and describe groundwater flow above and below the Boom clay. Sub-regional model covering much smaller area is used to detrive the groundwater flow conditions at the boundaries of a detailed site-specific transport model. This transport model is used to calculate the expected concentrations of radionuclides in groundwater.

Structure of hydrogeological models used to describe the groundwater flow and transport around the Boom Clay

Effects of changing climate

Hydrogeological investigations support the climate research by studying the effects of past climate changes on the aquifer systems (paleohydrogeology) and predicting the effects of future climate changes on planned disposal systems. Tackling such complex issue as future climate evolution requires a multidisciplinary approach including all disciplines of the hydrogeological research.

Contact: Gedeon Matej