Résumé
The economy of developing countries strongly depends on water resources. For a better management of water resources, we need to know better its spatio-temporal variability. For the last 20 years water resources assessment in Western and Central Africa has been the main research field of the HydroSciences Montpellier (HSM) laboratory. There are three main external constraints to our studies: the lack of available data which drives our choice for rainfall-runoff models using only few input data and robust analysis tools; the large time and space scales which are those used by development plans; and the climate changes since 1970 which have had impacts of various magnitude and spatial scale across the region. This paper summarizes some results using tools and methods developed at the HSM Laboratory, and draws some perspectives of research in the field of regionalization in hydrology.