Integrating Surface Nuclear Magnetic Resonance and Transient Electromagnetic to Assess Groundwater Resources in Senegal and Kenya

This study demonstrates the value of integrating Transient Electromagnetic (TEM) and Surface Nuclear Magnetic Resonance (NMR) methods to characterize groundwater systems in data-sparse regions of Sub-Saharan Africa. Traditional hydrogeological assessments relying on boreholes are limited due to high costs and sparse spatial resolution. TEM provides high-resolution resistivity data, revealing the lateral and vertical extent of subsurface units, while NMR directly quantifies water content and the pore environment. Two case studies highlight this combined approach: a coastal aquifer in Senegal and a river system near Kakuma, Kenya. In Senegal, the data revealed a stratified aquifer system with a fresh upper unit overlying a deeper saline body, enabling assessment of potential vulnerability to saltwater intrusion. In Kenya, the methods identified saturated sand channel deposits within a clay-dominated floodplain, suitable for managed aquifer recharge and water extraction. By combining the resistivity sensitivity of TEM with the direct water content measurements of NMR, ambiguous interpretations-such as distinguishing between saline sands and clays-can be resolved. This integrated approach offers a non-invasive, scalable solution for hydrogeological mapping in remote or logistically constrained regions, supporting more informed groundwater resource management and planning.