While the government presented its Water Plan on March 30 and drought is still affecting a large part of France, Météo-France is launching Drias-Eau. This regional portal makes it possible to visualize, using maps, the local evolution of water resources according to the future evolution of the climate. Projections are available for the short, medium and long term, up to 2100.

The hydrological data of the future climate are part of the scenarios developed by the IPCC. The goal? “Allow all actors, users, local elected officials, researchers, professionals, to better understand the evolution of water resources in the years to come, on the scale of their territory, to better prepare for them. »explains Christophe Béchu, Minister for Ecological Transition and Territorial Cohesion, in the project presentation file.

The portal was developed within the framework of the European LIFE Water&Climate project coordinated by OiEau. It incorporates the first results of the Explore2 project, led by INRAE ​​and OiEau, which aims to update hydrological projections. It already includes simulations of the flow of rivers at nearly 850 points on the metropolitan network. It also includes data on evapotranspiration, soil moisture and runoff. Finally, it predicts the water equivalent of the snowpack, ie the quantity of water potentially available at the time of melting, as well as drainage (the quantity of water that infiltrates the ground). From the summer of 2024, it will also integrate data on groundwater and will reach nearly 4,000 simulation points on all the rivers in the territory.

DRIAS-Eau: predicting the evolution of water resources

For several decades, the availability of water has been decreasing in France. Especially, “renewable water resources, i.e. water provided by precipitation which does not return to the atmosphere and that of rivers, has fallen by 14% in mainland France, on an annual average, between the periods 1990-2001 and 2002-2018”, advance Météo-France, according to figures from the Ministry of Ecological Transition. And “between 2017 and 2020, more than 30% of the territory was affected each year by water use restrictions”adds the organization.

The water cycle and water availability is bound to evolve in the coming decades. According to Météo-France, we should notably expect, by 2050, “an increase in river flows in winter, a significant decrease in summer” in the case of a moderate greenhouse gas emission scenario. The facility also provides “up to twice less water in the snowpack in the Alps” et “a sharp increase in the number of days of dry soil”between +10 and +25 days in all regions, in the same scenario.

Drias-Eau is thus added to the Drias-climat portal, launched in 2012. The latter also models in the form of a map, region by region, various data associated with the future climate of France until 2100.