Groundwater provides about 40% of all human water abstractions and is an essential water source for terrestrial ecosystems and freshwater biota in rivers, lakes, and wetlands, as well as a keystone ecosystem in itself. Aquifers may span political and natural boundaries, connecting people, ecosystems, and different parts of the hydrological cycle. However, our large-scale understanding of groundwater processes and the connection between ground and surface waters is still limited.
The development of global groundwater models and big-data assessments of groundwater wells have helped to push the boundaries of our large-scale understanding of groundwater processes. In particular, knowledge of the exchange between surface and subsurface waters is essential for determining the water balance at larger scales. Surface and subsurface water exchanges and inter-catchment groundwater flow affect water, pollutant, and nutrient fluxes, bio-organisms in streams, and the groundwater itself. Additionally, human activities (e.g., pumping/irrigation) increasingly affect groundwater flow processes and the exchange between surface and subsurface waters.
In this session, we want to highlight the increasing interest in the large-scale study of groundwater availability, quality, and processes (including groundwater recharge) and discuss current obstacles related to data availability and model design. Therefore, we seek contributions that address issues including:
* Continental to global groundwater-related datasets
* Regional to global big-data assessments with models and machine learning
* Transboundary and inter-catchment assessments of groundwater processes
* Identification of dominant controls on groundwater processes across large domains
* Recent methodological developments for the inclusion of small-scale hydrological processes into large-scale estimates
* Surface-subsurface water exchange and its effects on hydrological extremes (drought/flood), water availability, and solute and pollutant transport
* Effects of climate change, land use change, and water use change on global groundwater
* Implications of large-scale groundwater understanding on monitoring design, integrated water management, and global water policies
* Large-scale groundwater assessments related to the fulfillment of the UN sustainable development goals (SDGs)