Hydrochemical and Groundwater Flow Patterns of the Dabus River Catchment, Western Ethiopia: A Multivariate Approach

Groundwater is a critical resource worldwide, particularly in regions dependent on complex aquifer systems, where understanding its quality and flow dynamics is essential for sustainable management. In many crystalline basement and volcanic aquifers, such as those found in the western Dabus River catchment of western Ethiopia, there is very limited information on the hydrochemical evolution and the processes that regulate the groundwater composition. The main goal of this research is to characterize the hydrochemical evolution of groundwater in the mixed geological setting by performing a detailed hydrochemical survey and identifying the geochemical processes that are predominant in the water quality. In this regard, forty-seven (47) groundwater samples were collected from boreholes, hand-dug wells, and springs for the analyses. Hierarchical cluster analysis was carried out to categorize three hydrochemical groups that are differentiated by their spatial variability, which is governed by geological and hydrological factors. The interaction of water with rocks and the exchange of cations appears to be the main processes that influence the groundwater chemistry, which is in agreement with the modeled flow direction. The silicate weathering and human activities were suggested to be the second and third factors, respectively. These results provide foundational information about the groundwater evolution in the catchment and demonstrate that the applications of hydrochemical methods along with hydrological models can improve the knowledge and conceptualization of the groundwater in aquifer systems of a similar nature.