In situ Physicochemical Characterisation of Spring Waters in Crystalline Basement Environments: A Comparative Analysis with Surface Waters and Deep Groundwater in Daloa, Côte d’Ivoire

Abstract

Maintaining the availability of groundwater, in terms of both quantity and quality, is essential to guarantee access to drinking water in many countries around the world, particularly in the bedrock regions of West Africa. In most crystalline bedrock areas of West Africa, due to the poor quality of surface water, people are increasingly turning to groundwater, particularly water from springs. In the municipality of Daloa (central-western Côte d’Ivoire), spring water is increasingly being used by all social groups to meet their drinking water needs. This study aims to understand the interactions between different water resources using physicochemical parameters in order to better guide policies for the management of springs in the localities of Daloa, which are under increasing pressure from the local population. This study is based on the statistical analysis of a dataset collected during a campaign to measure the physicochemical parameters of water in the Tétégbeu River catchment area in Daloa. Data collection was carried out according to a rigorous protocol, with quality control checks performed on each parameter measured. The physicochemical parameters, notably temperature, pH, electrical conductivity and redox potential, were measured in situ using a multi-parameter analyser. The results show that the spring waters generally exhibit physicochemical characteristics intermediate between those of surface water and deep aquifers. However, several parameters, notably temperature, pH, electrical conductivity and redox potential, indicate a closer resemblance to water from deep aquifers extracted via boreholes. This similarity suggests that deep aquifers contribute to the existence of the springs, with a limited but not negligible contribution from watercourses (rivers). Thus, the springs appear to be transitional waters that emerge from shallow aquifers with a contribution from deep aquifers, but which may be locally influenced by inflows from rivers. This dual influence gives the springs a distinctive physicochemical signature, reflecting both the dynamics of underground flow and interactions with the surface environment. These results contribute to a better understanding of the hydrogeological behaviour of spring waters in a crystalline basement context and provide an essential basis for guiding spring management policies, particularly in the face of increasing pressure from human activities.