Mountains are an essential component of the Earth system and are widely recognised as major sources of freshwater. Their water resources support communities and ecosystems within mountain regions and are also critical for social-ecological systems further downstream.

The strong heterogeneity in hydro-meteorological conditions arising from elevation gradients, complex topography, and geological conditions makes hydrological processes highly variable across space and time. Climate change and growing human pressures are altering these processes, highlighting the need to better understand the controls on water resources and related ecosystem services. Mountains are therefore unique sentinels of global change, providing a setting for detecting, understanding, and monitoring its effects.

This session brings together researchers working on mountain hydrology worldwide to share the latest findings, innovative approaches, and new perspectives. Emphasis will be placed on the role of mountain regions in the water cycle and in providing, storing, and regulating water resources, as well as on the challenges of observing and understanding hydrological change in these complex environments. We invite contributions addressing past, present, and future conditions, including changes driven by climate and land-use change, their impacts on mountain and downstream regions, and adaptation strategies to support the long-term sustainability of mountain ecosystem services. We particularly encourage contributions on technological and methodological innovations that help overcome observational challenges.

Topics of interest include, but are not limited to
- sources of information for assessing past and present conditions in mountain surface-water and groundwater systems;
- innovative observational approaches and emerging data sources for characterising hydrological processes in mountains and their spatio-temporal variability;
- modelling approaches for assessing, attributing, and projecting hydrological change;
- methods to identify and disentangle drivers of hydrological change;
- prediction, evolution, and impacts of hydrological extremes;
- case studies on adaptation to changes in availability of water resources and associated risks;
- integration of complementary sources of evidence and knowledge, including citizen science, Indigenous knowledge systems, and other approaches that improve understanding of mountain systems and support the sustainable management of water resources