Contribution of Electric Tomography, Chemical and Isotopic Tools to the Understanding of the Resilience and Salinization of Wetlands along the Northern Coast of the Cape-Verde Peninsula: The Case of the Retba Lake
On the northern coast of the Cape Verde peninsula, Lake Retba is one of the
few depressions that have preserved its water body due to the drought that
plagued the Sahel in the 1960s. The aim of this article is to understand the resilience of the lake to the drought. For this purpose, a deep knowledge of interactions between the different components of the hydro-system, namely: lake,
dune tablecloth, ponds and ocean is necessary. The use of electrical resistivity
tomography (ETR) and chemical and isotopic tools yielded conclusive results.
Electrical tomography of resistivity (ETR) shows throughout the coastal dune
a superposition between fresh and salt water, with even a predominance of salt
water at the level of the old canal. The chemistry of the major ions and isotopes
confirms this contact between the saltwater bison of the sea and the lake by
showing a superposition of the fresh/brackish waters on the salty waters of the
bevel, which, in turn, are found in the very salty waters influenced by the lake.
This translates a feeding of the lake by the sea through the bevel. At the canal
level, this feeding is done, on the surface, by means of ponds whose water characteristics show that they constitute an outcrop of the bevel. The freshwater
body of the coastal dune that floats on salt water in the form of a lens also flows
into the lake. The feeding of the lake, by the sea through the bevel and the
ponds, and by the water table, is therefore effective and attested by all the methods used in this work. It allowed the resilience of the lake against the drought.
This inflow of seawater into the lake is at the origin of its salinization and
How to cite this paper: Gueye, M., Gning,
A. A., Ndiaye, M., Ngom, F. D., Malou, R.,
Sow, E. H., & Sarr, R. (2019). Contribution
of Electric Tomography, Chemical and Isotopic Tools to the Understanding of the
Resilience and Salinization of Wetlands along
the Northern Coast of the Cape-Verde Peninsula: The Case of the Retba Lake. Journal of Geoscience and Environment Protection, 7, 36-57.
Received: July 26, 2019
Accepted: September 16, 2019
Published: September 19, 2019
Copyright © 2019 by author(s) and
Scientific Research Publishing Inc.
This work is licensed under the Creative
Commons Attribution International
License (CC BY 4.0).
Open AccessM. Gueye et al.
DOI: 10.4236/gep.2019.79004 37 Journal of Geoscience and Environment Protection
therefore of the salt that settles on the bottom. This study shows that the survival of the lake also depends on safeguarding the ponds located in the north
of the lake.
Auteur(s) : Gueye M., Gning A. A, Ndiaye M., Ngom F. D., Malou R., Sow E. H., Sarr R.
Pages : 36-57
Année de publication : 2019
Revue : Journal of Geoscience and Environment Protection
N° de volume : 7
Type : Article
Mise en ligne par : MALOU Raymond