Over the last few decades, important advances have been made in the development of relevant hydrogeological conceptual models for crystalline aquifers, and notably for weathered-fractured crystalline aquifers. Paradoxically and contrary to other types of aquifers, these researches never aimed at characterizing springs, the places were groundwater naturally outflows from such aquifers. With such an objective, our methodological approach consisted first of a lithological and hydrogeological description of the aquifer system based on borehole data and outcrops in a representative weathered-fractured crystalline aquifer (Daloa, Ivory Coast). Next, electrical resistivity tomography (ERT) has been used (after validating the appropriate inversion method) to provide the imagery of the weathering profile both below the plateaus and in the valleys where the springs outflow. Piezometric and river discharge data were also processed notably to determine the direction of groundwater flow. Results demonstrate unambiguously that the isalterites aquifer supplies the springs, and that the underlying fractured layer is not directly implied in this supply. ERT combined with borehole and field lithological data also shows that the lateritic formations (alloterites) present near surface below the plateaus, as well as the upper part of the isalterites, were eroded in the valleys, but not deep enough to let the fractured layer outcrop. This conceptual model for springs not only provides a basis for characterizing such complex aquifers, but also provides technical guidance for spring catchment and groundwater protection in these crystalline areas.

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.