Evidence of hydrological regime shifts associated with a major decades-long drought in West Africa

2026

Article référencé dans le Web of Science WOS:001819988800012

Peugeot Christophe, Wendling V., Le Roux E., Panthou G., Hector Basile, Rouché Nathalie, Crespin-Boucaud Arthur, Favreau Guillaume, Dobi F. B., Cohard J. M., Demarty Jérome, Descroix Luc, Etchanchu Jordi, Grippa M., Hiernaux P., Warzagan A. I., Kergoat L., Abdou M. M., Mougin E., Pierre C., Rajot Jean-Louis, Vandervaere J. P., Vischel T., Lebel Thierry

Nature Communications, 2026, 17 (1), p. 6162 [14 p.]

Using ground-based meteorological, hydrological and land cover datasets from 1950 to 2015, we provide evidence that the increase in runoff observed in the semi-arid central Sahel (West Africa) since the 1970-1995 drought is a shift between alternative stable states of low and high runoff. We propose a conceptual model, governed by feedback loops between vegetation and surface runoff, which describes the stabilising mechanisms of each state and the basin-scale impact of local shifts. While the drought was likely the trigger for the shift, land clearing and rainfall intensification may have reinforced it. Due to wetter conditions and greater resilience, other basins further south did not shift. Our study suggests that the shift towards higher runoff is due to surface processes playing a dominant role in this region, with minimal contribution from subsurface processes. This regime shift framework offers a promising perspective on understanding long-term hydrological changes.

Sciences du milieu [021] ; Hydrologie [062]

AFRIQUE DE L'OUEST ; MALI ; BURKINA FASO ; NIGER ; BANIN ; NIGERIA ; ZONE SAHELIENNE ; ZONE SOUDANIENNE

Fonds IRD [F B010097610]

fdi:010097610