Modelling water and energy fluxes in the Seine basin

Managing water resources and the environment requires the integration of global changes, including climate change. Our understanding of water resources is often based on hydrological models. With these models, we can estimate the water balance of a study area and use these models to understand pollutant transport for environmental protection. Until recently, hydrological models only included water flow processes. However, climate change is manifesting itself in increasing temperatures in the atmosphere. The impact of climate change on river systems and groundwater resources is still poorly understood. This work aims to address this gap in the literature, namely the lack of quantification of the impact of climate change on riverine and groundwater resources. To do so, we combine two models that simulate water and energy fluxes at the soil‐vegetation‐atmosphere interface (ORCHIDEE), groundwater and surface water stocks and fluxes (CaWaQS). We apply our combined model to the Seine River basin, which provides water to more than 16 million people, to establish energy and water balances. Energy balances at the scale of the Seine aquifer system as well as its river system are established for the first time. We also project our combined approach to future climate conditions to assess possible changes in the hydrological and thermal regimes of the Seine basin waters.