Integrated chain for the hydrometeorological forecasting of low flows and droughts in France. The CIPRHES project

International audience ; There has been a growing interest in extending forecast lead times to facilitate water resources planning and management during droughts and low-flow events. This can be partly achieved by improving integrated hydrometeorological forecasting systems, which offer forecasts of future meteorological and hydrological conditions over continuous space and time scales. Several initiatives have been recently carried out at continental or global scales, in Europe and worldwide, to set up forecasting chains that run with numerical weather and climate model predictions as input to distributed hydrological models. Overall, these systems have been developed in response to a call for seamless forecasts in time (from short to medium and long-ranges) and space (at well-monitored and partially-monitored or ungauged catchments). These systems usually have to deal with limited calibration and evaluation against local data.In France, the CIPRHES project (2021-2025) aims at building an efficient and integrated methodology and an online operational service for a country-wide hydrological drought and low-flow forecasting system, based on the proof-of-concept PREMHYCE platform. The first step focuses on producing seamless atmospheric forecasts, combining information from climatology, weather predictions and seasonal forecasts. Then forecasts are post-processed and tailored for hydrological purposes of drought and low-flow forecasting.The first outcomes of the project will be presented, towards providing short- to long-term seamless hydrological forecasts. The outputs of a workshop organized with end-users to improve a forecasting prototype will be discussed.The CIPRHES project is funded by the French National Research Agency (grant ANR-20-CE04-0009-03).