Aqui-FR: Towards a hydro-geological seasonal forecasting system for metropolitan France.

Abstract : In France, groundwater is an important resource for industry, irrigation, and drinking water. As the dry periods become more frequent and longer due to the changing climate, it is crucial to forecast water table level evolution for the forthcoming months. Regional groundwater flow models can be useful to reach this objective. Downscaled atmospheric seasonal forecasts are generally used to feed hydrological surface models, which provide surface conditions (drainage, runoff) to groundwater flow models. Our application aims at using the Aqui-FR hydro-geological modelling platform for assessing the groundwater level for the forthcoming months. Aqui-FR was developed in order to gather in a single numerical tool several regional hydrogeological models covering much of the French metropolitan area. It allows to simulate the evolution of groundwater resources on short to long term periods. Since the beginning of 2020, a real time prototype has been set up. Every month, it provides a status of the water table and a monthly forecast for the next six months using the atmospheric seasonal forecast produced at Météo-France. These results are posted on an experimental website accessible to a group of beta-users. Some of them rely on this tool to help them in their decision making in a drought alert situation. For the first time in 2021, a hydro-geological seasonal forecast bulletin has been produced and provided to the national committee for drought monitoring and anticipation.