Salinity of Senegalese phreatic aquifers: the role of the geomorphology?
Salinity is a common feature in amphibious environments. However, in Senegal (West Africa), elevated salinity levels are observed in groundwater hundreds of kilometres inland from the coastline – far beyond the marine influence. This raises questions about the origin of the salinity, decoupled from seawater intrusion. A spatial alignment of high (and, conversely, low) salinity values – parallel to a dune system – suggests a potential link to these aeolian formations. Field observations in four distinct regions of northwestern Senegal reveal sharp salinity contrasts between dunes and adjacent interdune depressions, even at scales of just a few hundred metres. Electrical conductivity (EC) values can shift abruptly from low (EC < 0.5 mS/cm) to high (EC > 5 mS/cm). The findings, reinforced by a principal component analysis based on data from over 500 wells, support a geomorphological hypothesis to explain the spatial distribution of salinity, highlighting the influence of palaeoenvironmental features on present-day hydrogeochemistry.
Authors
- Sylvie Paméla Manga
- Céline Duwig (ORCID: https://orcid.org/0000-0003-1505-8996)
- Ababacar Fall (ORCID: https://orcid.org/0000-0002-1565-1979)
- Didier Orange (ORCID: https://orcid.org/0000-0001-8693-1778)
- Oumar Marega (ORCID: https://orcid.org/0000-0001-5422-9394)
- Jean‐Pierre Vandervaere (ORCID: https://orcid.org/0000-0002-9620-0589)
- Ange Bouramanding Diedhiou
- Yancouba Sané
- Marie-Jeanne Senghor
- Olivier Grünberger (ORCID: https://orcid.org/0000-0003-1285-7637)
- Jean‐Louis Rajot (ORCID: https://orcid.org/0000-0002-3428-5636)
- Laurence Fleury (ORCID: https://orcid.org/0000-0001-8261-4644)
- Luc Descroix (ORCID: https://orcid.org/0000-0001-6477-1195)
- Souleymane Niang
- Yasmin Bouaïta
- Waly Faye
- Lorenzo Spadini
- Olivier Ruë
Institutions
- University of Geneva (CH)
- Université d'Orléans (FR)
- Institut National de la Recherche Agronomique (MA)
- American Society of Safety Professionals (US)
- Aix-Marseille Université (FR)
- Université Amadou Hampaté Ba (SN)
- Institut de Recherche pour le Développement (CG)
- West African Science Service Centre on Climate Change and Adapted Land Use (GH)
- Laboratoire Population Environnement Développement (FR)
- Laboratoire d'études sur les monothéismes (FR)
- Institut des Géosciences de l'Environnement (FR)
- École Polytechnique de Thiès (SN)
- Institut de Recherche pour le Développement (FR)
- Université Grenoble Alpes (FR)
- Cheikh Anta Diop University (SN)
Publication Details
- Journal
- Hydrological Sciences Journal
- Published
- 2026-09-16
- DOI
- https://doi.org/10.1080/02626667.2026.2719885
- Primary Topic
- Groundwater and Isotope Geochemistry
- Type
- article
- Field-Weighted Citation Impact
- 0.00