Javier Zabalza-Martínez

Water resources availability is one of the main concerns for policy makers around the World. In the Mediterranean basin, this problem has been increased given the extreme variability in climate and the land use changes that have occurred during the last century (i.e. land abandonment). Streamflow and other environmental variables related to vegetation have been analysed in three Mediterranean mid-mountain basins under conditions of Climate Change (CC), under conditions of Land Use Change (LUC) and under its Combined Action (CA). The Land Use changes have been defined in the framework of the Life MIDMACC project and are related to land management through shrubland cleaning activities in abandoned fields and forest management that is determined by a 50% decrease in tree density in a forest community.Three basins (Leza, Estarrún and L'Anyet) have been simulated using the Regional Hydro-Ecologic Simulation System (RHESSys) for the periods 2035-2064 and 2070-2099. The aim of the study is to determine the impacts of climate change and land management on both streamflow and other variables such as Net Primary Production or Potential Evapotranspiration in these basins (representative of Mediterranean mid-mountains) in order to analyse how the management proposed can be used to adapt these basins to climate and whether it is capable of mitigating the forecast reduction in streamflow associated with climate trends.The results with LUC reveal a clear positive trend, increasing the streamflow in the basins of Leza and L'Anyet rivers (+9.76% and +4.70%) and slightly decrease (-0.13%) in Estarrún river due to the limited area to be managed. The combined action (CA) shows, in general, an attenuation in the clear negative trend of streamflow under climate change (CC) conditions. This suggests that the land management proposed in the LIFE MIDMACC project could help the adaptation of Mediterranean mid-mountain basins to climate change and the mitigation of its effects.Acknowledgements: This research project was supported by the Life MIDMACC project ((LIFE18 CCA/ES/001099)) project funded by the European Commission. Melani Cortijos-López is working with an FPI contract (PRE2020-094509) from the Spanish Ministry of Economy and Competitiveness associated to the MANMOUNT project. Manel Llena has a “Juan de la Cierva Formación” postdoctoral contract (FJC2020-043890-I/AEI/ 10.13039/501100011033) from the Spanish Ministry of Science and Innovation.  

This paper evaluates the response of streamflow in a Mediterranean medium-scaled basin under land-use and climate change scenarios and its plausible implication on the management of Boadella–Darnius reservoir (NE Spain). Land cover and climate change scenarios supposed over the next several decades were used to simulate reservoir inflow using the Regional Hydro-Ecologic Simulation System (RHESsys) and to analyze the future impacts on water management (2021–2050). Results reveal a clear decrease in dam inflow (−34%) since the dam was operational from 1971 to 2013. The simulations obtained with RHESsys show a similar decrease (−31%) from 2021 to 2050. Considering the ecological minimum flow outlined by water authorities and the projected decrease in reservoir’s inflows, different water management strategies are needed to mitigate the effects of the expected climate change.