Geohydrological assessment of a coastal sector located between Bahía Bustamante and Camarones, Chubut, Argentina

Abstract

In arid coastal areas, groundwater is usually brackish and coastal ridges are often sites where freshwater lenses are generated. The purpose of the study was to explore hydrogeologically and geoelectrically the area between Bahía Bustamante and Camarones in order to evaluate the feasibility of the sequence of coastal ridges in that area to constitute freshwater lens reservoirs. A regional water source survey was carried out, where the electrical conductivity of the water and the phreatic level were measured. On the Pleistocene and Holocene littoral ridges, vertical electrical soundings and soil description and infiltration tests were carried out. The studies carried out indicate that the Holocene ridges present more favorable conditions for rainwater infiltration and its storage in the form of freshwater lenses than the Pleistocene ones. However, the presence of freshwater lenses has not been identified in any of the coastal ridges explored. The development of soils with argillic and calcic horizons is probably the main reason why the Pleistocene cords do not constitute preferential recharge zones. Although the Holocene cords present favorable characteristics to host freshwater lenses, the reduced areal development of these geoforms could be a conditioning factor for their development. The results obtained show the need to carry out more detailed hydrogeological studies to verify the geohydrological functioning of the area.