At present, and mostly because it shares seasonally alternating hydrological processes characteristic of wet and dry basins, Mediterranean mountain area hydrology is still much less understood than the hydrology of more temperate or drier environments.
The research conducted by the Surface Hydrology and Erosion Group (IDAEA-CSIC) is oriented to the study of the hydrological dynamics of Mediterranean areas through a multidisciplinary and multiple-scale approach. Several aspects of the hydrological cycle are investigated, using mostly the Vallcebre Research Catchments (NE Spain) as a field laboratory to observe, quantify and model hydrological processes at the plot and catchment scale.
Since 2018, the Surface Hydrology and Erosion Group is also integrated within the Freshwater Ecology, Hydrology and Management research group (FEHM-Lab)(http://www.ub.edu/fem), in order to develop common approaches in hydrological and ecological research with a special focus on temporary rivers.

• Ecohydrology
  • Ecohydrological research in the Vallcebre research catchments started, 20 years ago, with the quantification and modelling of both rainfall interception and evapotranspiration of representative Mediterranean forest. Ongoing investigations focus on the study of: (a) the effect of spatial and temporal variability of throughfall on the variability of soil moisture, (b) the role of stemflow as a hotspot of preferential flow and (c) the spatio-temporal variability of throughfall and stemflow isotopic composition in relation with atmospheric conditions and rainfall characteristics.
• Hydrological changes
  • This research line started with the assessment of the effects of climate variability and land use and cover changes on the flow response, in a range of medium-sized catchments (up to few thousands km²). Recently, we developed a new investigations related with the effect of forest management practices, carried out in the Vallcebre research catchments, on the hydrological response and groundwater recharge dynamics.
• Rainfall-runoff dynamics and runoff processes
  • In the Vallcebre research catchments, the rainfall-runoff dynamics and runoff generation processes have been studied since 1989, using a hydrometric approach, and environmental tracers (since 2011). Ongoing investigations are focused on improving our understanding of the spatio-temporal variability of the hydrological response and of the dynamics of water fluxes and residence times at the plot and catchment scale. We also combined empirical and modelling approaches at different spatio-temporal scales in order to test hydrological models in Mediterranean conditions and to investigate the hydrological functioning of Mediterranean headwater catchments and their potential alteration due to future land-use and climate changes.
• Soil erosion
  • Vallcebre is internationally recognized as a reference site for badland research, particularly under montane Mediterranean conditions, where the occurrence and dynamics of these highly erosive landforms are driven by the combined biological and geomorphic effects of winter freezing and intense rainstorms in summer. The large spatiotemporal variations of erosion and basin sediment transport rates justify the importance on long-term studies on these processes.
• Temporary rivers
  • The aquatic life in temporary stream reaches is strongly dependent on the temporal changes of the aquatic habitats, determined by the hydrological conditions. This axis is done within the multi-disciplinary consolidated research group FEHM (Freshwater Ecology and Management lab). This is providing the European River Basin Authorities and relevant stakeholders with advice and operational tools for sound implementation of the Water Framework Directive to this kind of water bodies.