The aim of this fifth HydroEco conference – after the four previous meetings, in Karlovy Vary (Carlsbad), Czech Republic in 2006, in Vienna in Austria in 2009 and 2011, and in Rennes in France in 2013 – is fourfold: i) to present new findings and approaches on interactions between hydrology and ecology, ii) to promote interdisciplinary interactions on water related issues between hydrology, hydrogeology, biogeochemistry, microbial ecology and ecology iii) to explore advances in monitoring, modelling and predicting dynamics of hydroecological processes, and iv) to discuss management approaches and applications to tackle environmental issues, including engineering measures for ecosystem preservation and restoration of ecologically valuable environments. To address the relevant issues, the conference aims to bring together experts from different disciplines such as hydrologists (groundwater, surface water), ecologists, biologists, subsurface microbiologists, environmental biogeochemists, eco-technologists, geomorphologists, hydraulic engineers, forest managers, nature reserve managers, regional and landscape planners, as well as experts from governmental institutions. The unifying theme is the interaction between groundwater and (or) /surface water and ecological systems. A typical example is the hyporheic zone in riparian areas, where the ecological system interacts with water and chemical flows between surface water, groundwater and unsaturated soil zone.