Next Article in Journal
Water Crisis in Petorca Basin, Chile: The Combined Effects of a Mega-Drought and Water Management
Next Article in Special Issue
Climate and Extreme Rainfall Events in the Mono River Basin (West Africa): Investigating Future Changes with Regional Climate Models
Previous Article in Journal
Effects of Dam Regulation on the Hydrological Alteration and Morphological Evolution of the Volta River Delta
Previous Article in Special Issue
A Comparative Study of Statistical Methods for Daily Streamflow Estimation at Ungauged Basins in Turkey

Inverse Estuaries in West Africa: Evidence of the Rainfall Recovery?

IRD UMR PALOC MNHN/IRD/Sorbonne-Université, 75231 Paris, France
LMI PATEO, UGB, BP 234 Saint Louis, Senegal
UASZ Université Assane Seck de Ziguinchor, BP 523 Ziguinchor, Senegal
Université de Lorraine, UFR des Sciences Humaines et Sociales, 54015 Nancy, France
LMI ECLAIRS, UASZ, ENS, BP 5036 Dakar, Senegal
LaSTEE, Ecole Polytechnique de Thiès, DPA 10 Thiès, Senegal
ESPACE Lab, Université Côte d’Azur, UFR Espaces & Cultures Campus, 06204 Nice, France
Université Versailles St Quentin en Yvelines, UFR Sciences Sociales, 78280 Guyancourt, France
DGPRE, Direction de la Gestion et la Planification des Ressources en Eau, section 2, 20000 Diamniadio, Senegal
IRD/Laboratoire d’Océanographie Physique et Spatiale (LOPS), IUEM, Univ. Brest, CNRS, IRD, Ifremer, 29280 Plouzané, France
IRD/IEES; Institut d’écologie et des sciences de l’environnement, 93143 Bondy, France
IGE/Université Grenoble Alpes; Institut des Géosciences et Environnement, 38058 Grenoble, France
Author to whom correspondence should be addressed.
Water 2020, 12(3), 647;
Received: 26 January 2020 / Revised: 23 February 2020 / Accepted: 24 February 2020 / Published: 28 February 2020
In West Africa, as in many other estuaries, enormous volumes of marine water are entering the continent. Fresh water discharge is very low, and it is commonly strongly linked to rainfall level. Some of these estuaries are inverse estuaries. During the Great Sahelian Drought (1968–1993), their hyperhaline feature was exacerbated. This paper aims to describe the evolution of the two main West African inverse estuaries, those of the Saloum River and the Casamance River, since the end of the drought. Water salinity measurements were carried out over three to five years according to the sites in order to document this evolution and to compare data with the historical ones collected during the long dry period at the end of 20th century. The results show that in both estuaries, the mean water salinity values have markedly decreased since the end of the drought. However, the Saloum estuary remains a totally inverse estuary, while for the Casamance River, the estuarine turbidity maximum (ETM) is the location of the salinity maximum, and it moves according to the seasons from a location 1–10 km downwards from the upstream estuary entry, during the dry season, to a location 40–70 km downwards from this point, during the rainy season. These observations fit with the functioning of the mangrove, the West African mangrove being among the few in the world that are markedly increasing since the beginning of the 1990s and the end of the dry period, as mangrove growth is favored by the relative salinity reduction. Finally, one of the inverse estuary behavior factors is the low fresh water incoming from the continent. The small area of the Casamance and Saloum basins (20,150 and 26,500 km² respectively) is to be compared with the basins of their two main neighbor basins, the Gambia River and the Senegal River, which provide significant fresh water discharge to their estuary. View Full-Text
Keywords: water salinity; inverse estuaries; West Africa; drought; mangrove water salinity; inverse estuaries; West Africa; drought; mangrove
Show Figures

Figure 1

MDPI and ACS Style

Descroix, L.; Sané, Y.; Thior, M.; Manga, S.-P.; Ba, B.D.; Mingou, J.; Mendy, V.; Coly, S.; Dièye, A.; Badiane, A.; Senghor, M.-J.; Diedhiou, A.-B.; Sow, D.; Bouaita, Y.; Soumaré, S.; Diop, A.; Faty, B.; Sow, B.A.; Machu, E.; Montoroi, J.-P.; Andrieu, J.; Vandervaere, J.-P. Inverse Estuaries in West Africa: Evidence of the Rainfall Recovery? Water 2020, 12, 647.

AMA Style

Descroix L, Sané Y, Thior M, Manga S-P, Ba BD, Mingou J, Mendy V, Coly S, Dièye A, Badiane A, Senghor M-J, Diedhiou A-B, Sow D, Bouaita Y, Soumaré S, Diop A, Faty B, Sow BA, Machu E, Montoroi J-P, Andrieu J, Vandervaere J-P. Inverse Estuaries in West Africa: Evidence of the Rainfall Recovery? Water. 2020; 12(3):647.

Chicago/Turabian Style

Descroix, Luc, Yancouba Sané, Mamadou Thior, Sylvie-Paméla Manga, Boubacar D. Ba, Joseph Mingou, Victor Mendy, Saloum Coly, Arame Dièye, Alexandre Badiane, Marie-Jeanne Senghor, Ange-Bouramanding Diedhiou, Djiby Sow, Yasmin Bouaita, Safietou Soumaré, Awa Diop, Bakary Faty, Bamol A. Sow, Eric Machu, Jean-Pierre Montoroi, Julien Andrieu, and Jean-Pierre Vandervaere. 2020. "Inverse Estuaries in West Africa: Evidence of the Rainfall Recovery?" Water 12, no. 3: 647.

Find Other Styles
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

Back to TopTop