Understanding hydrological processes that occur when surface waters and groundwater merge into a unique hydrological system has significant importance for water management and resource allocation. The dynamics of groundwater/surface water exchanges are also important for the functioning of aquatic ecosystems, pollutant and nutrient transport as well as the quality and quantity of water supply to domestic, agricultural and recreational purposes.

The surface water and groundwater components of the hydrological system are still poorly understood, in particular in terms of the importance of each end-member and the temporal and spatial variability of exchange in between reservoirs. Moreover, an effort to upscale the findings from reach-scale studies to the catchment-scale as well as to incorporate the results in modelling efforts are also needed for an effective management of connected water resources.
A large variety of tools have been developed to assess the magnitude as well as the temporal and spatial variability of the exchange fluxes, including geophysical, hydrological and geochemical approaches, often combined together.
While these techniques need refining, the use of the resulting data in management relevant hydrological modelling is scarce. The link between field base observations and model approaches is weak.

This conference session encourages contributions from hydrogeologists, stream ecologists, microbiologists, geochemists, geomorphologists, coastal oceanographers and landscape ecologists in order to discuss new developments, field and analytical methods and techniques to reduce uncertainties in prediction of groundwater/surface water interactions and to better understand spatial and temporal variability of the exchange. In particular, approaches and methods allowing the detection and quantification of groundwater inputs to surface water, the tracing of water flow paths within the riparian and stream bed sediments and the understanding of hyporheic zone exchange mechanisms are welcome.

Research should be related to further development of hydrograph analysis, application of chemical and isotopic tracer techniques, geophysical techniques, modelling, as well as improved experimental designs in order to characterize spatial and temporal dynamics of hydrological and biogeochemical processes of connected water resources at the catchment and at the reach and sub-reach scales in terrestrial (rivers, lakes and wetlands) and coastal environments (e.g. SGD).