About two-thirds of global freshwater supplies come from surface waters such as the tidal fresh region of estuaries. A number of hydrological as well as coastal and open-ocean processes may affect the oceanic saltwater intrusion into estuaries and tidal rivers, including draughts, river floods, interactions with groundwater, sea-level rise, changing ocean circulation and regional sea level fluctuations, changing tides, storm surges, and extreme wind events. Moreover, engineering measures such as channel deepening and narrowing, as well as water management have a strong impact on estuarine salt intrusion. However, we have little understanding of how these processes work in concert with extended drought to drive the extreme salt intrusion under climate change. This gap in scientific knowledge has been exposed in a number of headline news reports on the salt contamination of drinking water supplies in tidal rivers. The Scientific Committee of Oceanic Research (SCOR) Working Group 172 „SALTWATER“ has the goal to shed light into these complex interdisciplinary problems of saltwater  intrusion and to develop concept and to develop a global synthesis of this emerging topic .

We invite contributions highlighting new findings on estuarine salt intrusion processes, using theoretical, observational, numerical, statistical or Machine Learning approaches.

• Coastal and Estuarine Hydrodynamics and Sediment Processes -