Hydrogeology is the science of groundwater and its interactions with rocks and geological structures. In most parts of the world, groundwater is the safest and most important source of drinking water in terms of both water quality and quantity. Hydrogeology deals with the occurrence, movement, quality, utilization and protection of groundwater. Our hydrogeological research includes observations, measurements and experiments both in the nature and in the laboratory, as well as numerical flow and transport modeling. We cover the entire range of groundwater research, with special focuses on alpine and karst hydrogeology, groundwater-dependent ecosystems, integrated water resources management (IWRM), pump and tracer tests, urban hydrogeology and thermal groundwater use.