Hydrogeophysical investigations in the western and north-central Okavango Delta (Botswana) based on helicopter and ground-based transient electromagnetic data and electrical resistance tomography

A groundbreaking hydrogeophysical study of the Okavango Delta, Botswana, reveals the subsurface structure beneath two critical regions—its western margin and north-central area. Using helicopter-based transient electromagnetic (HTEM) data alongside ground-based electrical resistance tomography (ERT) and transient electromagnetic (TEM) surveys, researchers uncovered a consistent three-layer resistivity model: a conductive middle layer flanked by resistive upper and lower layers. This model, validated across multiple datasets, suggests the presence of freshwater-saturated sediments from a Paleo Okavango Megafan, saline-water-saturated sands linked to ancient Lake Makgadikgadi, and modern megafan and fluvial deposits. The study bridges gaps in understanding the delta's sedimentary history, offering crucial insights for conservation and water resource management in this UNESCO World Heritage Site.

Meier, P., Kalscheuer, T., Podgorski, J. E., Kgotlhang, L., Green, A. G., Greenhalgh, S., Rabenstein, L., Doetsch, J., Kinzelbach, W., Auken, E., Mikkelsen, P., Foged, N., Jaba, B. C., Tshoso, G., & Ntibinyane, O. (2014). Hydrogeophysical investigations in the western and north-central Okavango Delta (Botswana) based on helicopter and ground-based transient electromagnetic data and electrical resistance tomography. Geophysics, 79(5), B201–B211. https://doi.org/10.1190/geo2014-0001.1