Spatial hydrology, an innovative tool for water management

Faced with climate change and the scarcity of water resources, OiEau is supporting the deployment of spatial hydrology, by leading the French working group on spatial hydrology since 2014, and through projects conducted in Africa on the Congo, Niger and Senegal river basins, as well as on the Guiana Shield in Central America.

A better understanding of the water cycle on a global scale is indeed essential to improve the management of water resources available for human activity, preserve biodiversity and reduce the risk of natural disasters.

Thanks to space agencies and several networks of actors, the observation of river basins through the eye of satellites is now possible. It is proving to be an essential tool for decision-making on water issues and risk prevention. However, these new dynamics imply a collective reflection on the development of specialized tools, on the modalities of use, on the actors involved as well as on the multisectoral perspectives.

This is the challenge of the scientific meetings "HYDROSPACE" which, since 2003, try to document the debate around satellite remote sensing on an international scale. In June 2021, OiEau participated in the workshop "Hydrospace - Geoglows" organized by the European Space Agency (ESA), CNES and the GEO Global Water Sustainability Initiative (GEOGloWs). 300 scientists from 41 countries took part in this exchange event which aimed to address the issues of satellite observation for groundwater storage.

From this collaborative work has emerged a comprehensive report that highlights the different thematic axes and the main recommendations to be taken into account: better coordination between actors, capacity building, development of a global storage system, appropriate dissemination of tools and data, and support for "open science".

OiEau is very involved in these topics since it has been leading, since 2014, a working group on space hydrology gathering both research actors (CNES, IRD, IRSTEA), institutional actors (AFD, OiEau) and private technical operators (BRL engineering, CNR, CLS). Its objective is to promote exchanges and reconcile the visions of stakeholders with the needs of users, around innovative technologies, particularly through the SWOT program, for the collection of spatial data useful for water management. Among these technologies, spatial altimetry, which allows the estimation of river heights and flows, and multi-sensor data collection (imagery, radar) are particularly noteworthy.

To date, these tools have made it possible to carry out numerous actions, including flood prevention in the Niger basin via satellite rainfall estimation and spatial altimetry, and the creation of a hydrological information system in the Congo basin for the development of hydroelectric potential and water level forecasting.

"The spatial hydrology group has chosen the Congo River basin as a pilot basin. Thanks to this cooperation, CICOS now has a hydrological information system combining in situ and spatial data, which is extremely useful to the Member States" Mrs. ENAW, borned Judith Efundem Agbor, Secretary General of the International Commission of the Congo-Oubangui-Sangha Basin.