Airborne Geophysical Mapping of Aquifer Water Quality and Structural Controls in the Lower Okavango Delta, Botswana

Groundwater exploration in the lower Okavango Delta to the west of Maun in northern Botswana has focussed on<br>the search for shallow fresh-water aquifers in Kalahari sediments. While surface water flow in the delta is fresh,<br>much of the shallow groundwater is saline and deep (~100m) groundwater is almost invariably saline, due to a<br>combination of evaporation, evapotranspiration and poor drainage. The target aquifers comprise thick packages of<br>coarser sands characterised by high porosity and permeability, allowing for annual flushing and recharge. For<br>these reasons, finer-grained, clay-rich sands are poorer targets.