Hydrogeochemical Fingerprinting and Reactive Transport Modelling for Sustainable Groundwater Management in Ghana’s Mining-Affected Pra Basin

• Applicant: Dr. Evans Manu
• Subject Area: Hydrogeology, Hydrology, Limnology, Urban Water Management, Water Chemistry, Integrated Water Resources Management
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 578118617

Groundwater contamination from artisanal and small-scale gold mining (ASGM) poses a critical threat to water security in many regions of Sub-Saharan Africa. In Ghana’s Pra Basin, groundwater is the primary source of drinking water for millions, yet it is increasingly at risk from toxic substances such as mercury, arsenic, and other heavy metals introduced by illegal mining practices. Although the environmental impacts of mining are well documented, there remains a limited scientific understanding of how these pollutants behave underground, how they are mobilized, transported, and transformed over time in complex hydrogeological settings. This project aims to address this knowledge gap by developing an integrated scientific framework that combines hydrogeochemical fingerprinting with reactive transport modeling to study contaminant pathways and inform sustainable groundwater management. The core innovation lies in tailoring advanced analytical and modeling tools traditionally applied in temperate environments for the tropical, mining-affected context of the Pra Basin. The project begins by building a robust baseline understanding of the groundwater system, using historical and newly acquired field data to develop a detailed conceptual model of aquifer structure, recharge zones, and flow dynamics. It then characterizes the hydrochemical regimes and pollutant signatures through high-resolution sampling and analysis of major ions, trace metals, rare earth elements, and isotopic tracers across seasons. These data are used to identify flow paths and distinguish between pollution sources. The study further applies statistical source apportionment methods to quantify the relative contributions of mining, agricultural, and natural sources to groundwater contamination. With this knowledge, a fully coupled groundwater flow and reactive transport model will be developed and calibrated using tools like MODFLOW and PHT3D. This model will simulate how contaminants move and transform under varying redox, sorption, and hydrological conditions. Finally, the model will be used to explore future development and climate change scenarios, assessing the vulnerability of groundwater systems under different mining intensities, land use patterns, and water demand conditions. The findings will provide science-based guidance for policy and water resource management. The project builds directly on the applicant’s doctoral research, which generated a unique dataset and conceptual model of the Pra Basin. The project represents a vital step toward establishing scientific independence and advancing hydrogeochemical research in data-scarce, mining-impacted tropical regions.

• DFG Programme: WBP Position