World Water Quality: a portal developed for UNESCO, based on a demonstrator on Lake Chad

Theia Colours of the Continental Waters SEC with the support of CNES and the SME Magellium, has developed the new World Water Quality portal for UNESCO and its Water Sciences Division. With this portal, UNESCO aims to promote innovative approaches to freshwater monitoring in order to address the lack of data and information on water quality at local, regional and global levels and to promote open access data sharing.

Available variables are the following:

  • suspended particulate matter concentrations,
  • turbidity,
  • chlorophyll-a concentration,
  • proliferation of harmful algae (HAB),
  • presence of dissolved organic matter
  • and surface temperature.

These data were produced using several thousand Sentinel-2 and Landsat-8 images. Monthly water masks and the altimetric variation of the main lake are also provided in order to provide a complete view of the evolution of water resources from satellite data.

These products were developed jointly by the IRD, OFB and INRAE teams through their GET (Geosciences Environment Toulouse) and RECOVER (Risks, Ecosystems, Vulnerability, Environment, Resilience) laboratories respectively, thus enhancing the methodological developments carried out within the framework of the THEIA consortium and with the support of CNES.

Lake Chad as a demonstrator

This first version of the portal concerns the Lake Chad Basin and was developed with the Lake Chad Basin Commission (LCBC) in the framework of the BIOPALT project ( which associates the five countries sharing the watershed (Chad, Nigeria, Niger, Cameroon, Central African Republic). It demonstrates the validity and importance of the CES work and its potential for use by a wide range of users.

The website can be accessed at
An introduction page to the project is available at the following address

Although the decrease in water surface area in the Lake Chad region since the 1970s is relatively well documented, this was not the case for the quality of these waters, which have not been monitored for several decades. Indeed, the complexity of this ecosystem, made up of hundreds of lagoons, as well as recent security problems, preclude any possibility of using conventional means of measurement with permanent equipment or regular water sampling. The lack of information represents a major obstacle to the diagnosis of the degradation of this exceptional ecosystem. The new data produced will therefore be essential for the development of policies and management priorities for the protection of water quality and ecosystems and for the implementation of the Sustainable Development Goals (SDGs) in the region.

This portal is a first step and a new phase is already being developed in the Rio de la Plata basin with UNESCO and institutions in the five countries that share this basin: Brazil, Bolivia, Paraguay, Uruguay and Argentina.



Jean-Michel Martinez
UMR GET – Directeur de Recherche IRD

Thierry Tormos
Pôle ECLA | Chef de projet OFB

Nathalie Reynaud

Tristan Harmel

Guillaume Morin

Mauricio Cordeiro

William Santini

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