Isotope Hydrology for Sustainable Development: Elucidating the Flood History and Age-Depth Profile of the Okavango Delta with Accelerator Mass Spectrometry

The current proposal seeks to provide depth-age profiling of the water in the Okavango Delta which builds on earlier work in which it was suggested that there is an older, deeper reservoir of groundwater in contrast to a younger, shallower distribution of surface, or near, surface water. The dynamics of the Okavango Delta floods varies greatly from year to year, but little is known about the extent of this variability. This proposal also aims to establish the flood history of the Delta using the same approach that was used for rainfall reconstruction. The proposal seeks to characterize the flood history of the Okavango Delta through the analysis of carbon isotope ratios obtained from baobab trees. As enabled by the current MoU, both the depth-age profiling and the flood history will make use of Africa’s only Accelerator Mass Spectrometry (AMS) facility located at iThemba LABS in Johannesburg, South Africa, on the campus of the University of the Witwatersrand. The project provides context and motivation for the establishment of the Botswana Institute of Nuclear Sciences and Technology (BINST) at BIUST as proposed and supported by the IAEA.

Life requires water and this is supplied to Botswana through the Okavango Delta. The present project proposal seeks to understand the hydrology of the Okavango Delta via nuclear isotopic analytical techniques.

To establish whether there is an older, deeper reservoir of groundwater in contrast to a younger, shallower distribution of surface, or near, surface water. Also to investigate the flood history of the Okavango Delta via rare isotope analyses of samples taken from pairs of baobab trees.