[en] Efficient and sustainable management of water resources should be considered from an integrated way, at the basin scale. For that purpose, physically-based, spatially distributed modelling tools has turned to be very useful. If regional groundwater flow model have been developed for years now, large scale contaminant transport models are still almost inexistent. The objective of this extended abstract is to present briefly new concepts for large transport modelling, more particularly a modelling approach, the Hybrid Finite Element Mixing Cell (HFEMC) developed by the Hydrogeology Group of the University of Liège and implemented in the 3D simulator SUFT3D. First steps for the application to the Geer basin are also presented.