Publications des scientifiques de l'IRD

Bouchez C., Deschamps Pierre, Goncalves J., Hamelin B., Nour A. M., Vallet-Coulomb C., Sylvestre Florence. (2019). Water transit time and active recharge in the Sahel inferred by bomb-produced Cl-36. Scientific Reports - Nature, 9, p. art. 7465 [8 p.]. ISSN 2045-2322.

Titre du document
Water transit time and active recharge in the Sahel inferred by bomb-produced Cl-36
Année de publication
2019
Type de document
Article référencé dans le Web of Science WOS:000468026100007
Auteurs
Bouchez C., Deschamps Pierre, Goncalves J., Hamelin B., Nour A. M., Vallet-Coulomb C., Sylvestre Florence
Source
Scientific Reports - Nature, 2019, 9, p. art. 7465 [8 p.] ISSN 2045-2322
The lack of data and suitable methods to quantify regional hydrological processes often hinders sustainable water management and adaptation to climate change in semiarid regions, particularly in the Sahel, which is known for its climatic variability. Here we show that Cl-36 from nuclear tests is a promising method to estimate water transit times and groundwater recharge rates on the catchment scale, and to distinguish water and chloride cycles. Cl-36 was measured in 131 surface and groundwater samples in the Chari-Logone sub-catchment of the emblematic Lake Chad Basin, located in central Sahel. It was found that only 12 +/- 8% of the catchment is connected to the main rivers. Groundwater supporting rivers in the upper humid part of the catchment has a mean transit time of 9.5 +/- 1 years and a recharge rate of 240 +/- 170 mm yr(-1). In the lower Sahelian part of the catchment, stream-focused recharge yields recharge rates up to 78 +/- 7 mm yr(-1) in riparian groundwater against 16 +/- 27 mm yr(-1) elsewhere. Our estimates suggest that aquifers in the Sahel host a significant amount of renewable water, which could therefore be used as a strategic freshwater resource.
Plan de classement
Sciences du milieu [021] ; Hydrologie [062]
Description Géographique
SAHEL ; ZONE SEMIARIDE ; TCHAD LAC
Localisation
Fonds IRD [F B010075722]
Identifiant IRD
fdi:010075722
Contact