Characterization of Groundwater Flow in the Environment of the Boom Clay formation

In Belgium, the Boom Clay formation is considered as reference host rock for the geological disposal of radioactive waste. Aquifers surrounding the Boom Clay play a passive role in the context of the disposal safety whereby the radionuclides are diluted by groundwater flow. The groundwater flow in these aquifers has been studied since decades. This research involves observations of groundwater levels in the regional and local piezometric networks, several site investigations including geophysics and core-drilled boreholes and groundwater modelling. In this context, groundwater modelling represents the integration of the site characterization efforts and provides a comprehensive tool for constraining the models used in the safety assessment of the geological disposal. The characterization programme along with the numerical modelling represents a sound basis for estimation of the safety assessment parameters, the derivation of the boundary conditions for the local and transport models and assessing the effects of the climate and other events.