Sandra Lanini, Hydrogeological modeller, BRGM (testimony from the “Explore2 project, hydrological projections to adapt water resource management” dossier – 2024)
“I develop different types of model depending on the complexity of the hydrosystems to be studied. In Explore2, I am using the RECHARGE model, which provides, for the whole of France and for each body of water, an estimation of the proportion of rainfall that infiltrates and potentially recharges the aquifers. To model groundwater, we use several other hydrogeological models to simulate changes in the hydraulic load and to reproduce as closely as possible observations of flow and groundwater levels at catchment scale. In order to model the impact of climate change on groundwater, we applied these models over the recent period to calibrate them on the basis of our observations, and then applied them to simulate scenarios in which external conditions varied. In Explore2, the models were run many times using different climate projections. In addition to the average results, it is important to note that the results vary widely depending on the climate projections used.”
Testimonial from our thematic dossier
Thematic dossier
The Explore2 project: hydrological projections to adapt water resource management
The Explore2 project, carried out between 2021 and 2024, aimed to describe the climate and water resources for the whole of the 21st century in mainland France, while ensuring that they are properly used. It produced a set of unprecedented projections in terms of the wealth of models applied and their spatial and temporal resolution, with no equivalent in Europe, thanks to a community of forty or so scientists from different organisations who were mobilised and united around the challenges of climate change. Around a hundred representatives of potential users of Explore2 results have also contributed to the project. Together, and under the guidance of INRAE and IOWater, they have devised useful information that can be mobilised by water managers in their territories. To provide a better understanding of the uncertainties associated with the projections, the scientists have proposed four climate narratives that illustrate the diversity of possible futures. Following the example of the IPCC, they have also drawn up a summary of the main conclusions at the level of mainland France for a set of descriptive variables in the water cycle, while specifying the degree of confidence in these results and the limits of knowledge. All the results of this project, which will have a major impact on water policy in France, are available online.
