Managing, handling, exchanging and accessing hydrogeological information depend mainly on the applied hydrogeological data models, which differ between institutions and across
countries. Growing interest in hydrogeological information diffusion, combined with a need for information availability, require the convergence of hydrogeological data models. Model
convergence makes hydrogeological information accessible to multiple institutions, universities, administration, water suppliers, and research organisations, at different levels: from the local level (on-site measurement teams), to national and international institutions dealing with water resources management. Furthermore, because hydrogeological studies are complex, they require a large variety of high-quality hydrogeological data with appropriate
metadata in clearly designed and coherent structures.
To respond to the requirement of model convergence, easy information exchange and hydrogeological completeness, new data models have been developed, using two different methodologies. At local-regional level, the HydroCube model has been developed for the Walloon Region in Belgium. This logical data model uses entity-relationship diagrams and it
has been implemented in the MS Access environment, further enriched with a fully functional user-interface. The HydroCube model presents an innovative holistic “project-based” approach, which covers a full set of hydrogeological concepts and features, allowing for effective hydrogeological project management. This approach enables to store data about the
project localisation, hydrogeological equipment, related observations and measurements. Furthermore, topological relationships facilitate management of spatially associated data. Finally, the model focuses on specialized hydrogeological field experiments, such as pumping tests and tracer tests.
At the international level, a new hydrogeological data model has been developed which guarantees hydrogeological information availability in one standard format in the scope of the FP6 project GABARDINE (“Groundwater Artificial recharge Based on Alternative sources of wateR: aDvanced Integrated technologies and management”). The model has been
implemented in the ArcGIS environment, as a Geospatial Database for a decision support system. The GABARDINE Geospatial Database uses advantages of object-oriented modelling (UML), it follows standards for geoscientific information exchange (ISO/TC211 and OGC), and it is compliant with the recommendations from the European Geospatial Information Working Group.
Finally, these two developed models have been tested with hydrogeological field data on different informatics platforms: from MS Access, through a proprietary ArcGIS environment, to the open source, free Web2GIS on-line application. They have also contributed to the development of the GroundWater Markup Language (GWML) Canadian exchange standard, compliant with Geographic Markup Language (GML). GWML has the potential of becoming an international HydroGeology Markup Language (HgML) standard with a strong and continuous support from the hydrogeological community.