Critical zones (CZ) are natural and anthropogenic environments where air, water, soil, and rock interact in complex ways with ecosystems and society. Groundwater is the largest reservoir in this integrated system, but it is often overlooked due to the challenges of accessing it and its slower movement compared to other CZ components. However, dedicated CZ observatories (e.g. eLTER and CZEN) and intensively instrumented study areas provide extensive and detailed data on groundwater flow under contrasting climates, geology, vegetation and land use, and offer the opportunity for comprehensive multi-site studies.. This session aims to showcase contributions that highlight such studies, which enhance our understanding of water fluxes within the critical zone and their crucial role in energy and material cycles.
We invite presentations that address key research questions, such as (i) How do components across different scales—from the vertical column, including the atmosphere, vegetation, soil, and bedrock, to large-scale hydrosystems, spanning headwaters and 2D hillslopes, and from surface waters and the vadose zone to the deeper limits of groundwater—interact and interconnect?, (ii) How can we bridge the gap between rapid subsurface and slow groundwater flow processes with longer-term environmental changes that collectively shape the critical zone? (iii) What are the potential consequences of climate warming, extreme weather events, and wildfires on groundwater recharge, discharge processes, and water quality?
This session aims to bring together researchers and scientists from diverse backgrounds to advance our understanding of groundwater’s role in the critical zone. We seek to illustrate how combining observations and numerical experiments can help delineate future predictions for groundwater systems under various climate and land-use evolution scenarios.