River networks are strongly interlinked systems of streams, rivers, floodplains, adjacent groundwater systems and that are highly sensitive to impacts of multiple pressures on global, regional and local scales. Changes within these ecosystems also impact the availability of water resources and have far-reaching consequences for our society. DANUBIUS Austria aims to establish a network of modern river observatories in the catchment of the Upper Danube (Supersite “Upper Danube and pre-alpine tributaries”) to obtain biogeochemical data with a high spatial and temporal resolution, which facilitates the observation and analyses of global change-induced long-term trends as well as short-term fluctuations in surface waters and coupled surface – groundwater systems. These river observatories are urgently needed for an advanced mechanistic understanding of the impacts of climate change, land-use intensification, and local human interferences on biogeochemical fluxes and other processes in river-floodplain-groundwater systems. This asks for innovative approaches and the combination of different techniques, including state-of-the-art in-situ observations, besides regular sampling surveys, outdoor experiments, and model development. Moreover, data acquisition must be multi-disciplinary, including water quantity, quality, and various ecosystem functions and services.

The two observational regions which form the supersite “Upper Danube and pre-alpine tributaries” include

1. the pre-alpine Ybbs stream and river network focusing on longitudinal changes of biogeochemical fluxes, and
2.  the Danube main stem with its adjacent floodplains (Danube Floodplains National Park) in the area of the city of Vienna, focusing on lateral and vertical exchange processes.

DANUBIUS Austria intends to establish several observational sites within these regions, which are equipped with automatized high-resolution recording of environmental parameters and biogeochemical processes in surface and groundwater. The research infrastructure applied will be embedded in DANUBIUS-RI, the International Centre for Advanced Studies on River-Sea Systems (www.danubius-ri.eu/), which is an ESFRI pan-European research infrastructure supporting interdisciplinary research on River-Sea-Systems on its way becoming an ERIC. The scientific vision of the supersites “Upper Danube Austria & pre-alpine network of tributaries” is to provide innovative, internationally relevant knowledge on aquatic ecosystems in a large river system in the alpine Upper Danube catchment relevant for the future sustainable use of river systems.