Dear Water Experts WELCOME TO BRUSSELS, BELGIUM In September 2018, in Daejeon, South Korea, the Council of the IAH decided to appoint the IAH Belgian National Chapter (the CBH-BCH) to organize the 48th International Congress of 2021. It’s a great honor, a wonderful pleasure and an exciting challenge to organize such an event. So there we go The congress will be held in Brussels, Belgium, from September 6-10 September, 2021, in the very heart of the Belgian and European Capital. The IAH Belgian Chapter is honored to host and invite you to the 48th IAH Congress in Brussels, Belgium in 2021. We our looking forward to be inspired by your contributions on the following topics: Groundwater/surface water interaction Hydrogeochemistry, groundwater age tracing, paleogroundwater and isotopes in hydrogeology Groundwater contamination Hydrogeophysics Groundwater and climate change Geothermal and hydro-energy Karst and fractured rock hydrogeology Managed aquifer recharge Mineral and thermal waters Regional groundwater systems and transboundary aquifers Coastal aquifers Urban groundwater Groundwater and ecosystems Advances in forward and inverse groundwater modeling and open source tools for computational subsurface hydrology Advances in experimental and field methods in hydrogeology and for understanding of the critical zone Groundwater governance, policy and management Sustainable groundwater exploitation and well management