Based on a first inventory of available case studies, test sites have been selected in the Walloon part of the Meuse Basin in Belgium. These sites meet the requirements and objectives of the researches performed by different partners in AquaTerra. Available information and datasets have been collected for these sites and complementary investigations and experiments have been organized. Existing data and recently collected data have been compiled into a hydrogeological database developed by HGULg for the Walloon region and adapted to the specificities and needs of the AquaTerra project. The deliverable provides a general description of the hydrogeological database developed by HGULg: the conceptual model, specific adaptations performed for the AquaTerra project and interfaces for encoding, querying and exporting hydrogeological information stored in the database. A synthesis of datasets available in the HGULg Hydrogeological Database for the selected test sites in the Meuse basin is also provided. ; AquaTerra - Integrated Modelling of the river-sediment-soil-groundwater system; advanced tools for the management of catchment areas and river basins in the context of global change