The SWOT (Surface Water and Ocean Topography) satellite will be launched in 2022 as part of a Franco-American CNES-NASA mission, also supported by the UK and Canadian space agencies.

The overall budget is around 1 billion dollars, and an investment programme for the future (PIA) has been granted to prepare the downstream products that will make the most of the satellite data collected. Well before the launch, CNES and NASA are very active in defining and preparing future uses.

Since 2014, INRAE (Montpellier) has been a member of the project’s international scientific team, working mainly on reconstructing river flows using data provided by the satellite.

This work is recognised by the international community, with numerous publications.

INRAE is currently testing its algorithm on some fifty rivers around the world.

Touted as a revolutionary new technology, SWOT will provide virtually complete coverage of the globe outside the poles: on a mesoscale for the oceans, but above all for continental hydrology (rivers and lakes).

Certain rivers have been selected for specific studies.

A working group on spatial hydrology was set up in 2014. Led by IOWater, it brings together several partners, French research, institutional, technical and operational players: CNES, IRD, AFD, INRAE, BRLI, CNR and CLS. Activities have been carried out with this consortium around the International Commission of the Congo-Oubangui-Sangha Basin (CICOS, created in 1999).

By 2022, the working group should be able to provide spatio-temporal variations in the water levels of major rivers, lakes and streams, and in the flows of major rivers and ocean levels. This spatial altimetry data opens up a wide range of prospects, both for scientific research and for the operational management of water resources, particularly for major transboundary rivers.

The Congo River has been chosen as the experimental river, as it is particularly interesting for its flow rate (the second largest in the world after the Amazon), its size (4,700 km), its challenges (river transport, irrigation, drinking water, hydroelectricity), and its international and cross-border nature (its catchment area crosses 7 countries).