Over the coming decades water demand are set to increase rapidly for Africa, primarily driven by population growth and increased by drier climate conditions. Increasing reliable fresh water supplies in Africa will depend on the development of groundwater (McDonald et al 2012). To ensure sustainable water use and avoid overexploitation improved knowledge of the groundwater resource is needed. In particular improved knowledge is needed for hardrock aquifers with thick regolith layers covering 44% of Africa.

Specifically, the following research goals are formulated:

1) Improve current available continental-scale subsurface parameterization by including local available data to estimate aquifer thickness, vertical structure, and conductivities.

2) Evaluate the new parameterization hydrologically by running the global groundwater model PCR-GLOBWB-MODFLOW (de Graaf et al 2017). Model results will be evaluated against groundwater head and discharge measurements.

The first part of this research will be more focussed on comparing and reviewing previous published datasets on thickness of sediment and regolith aquifers (e.g. Pelletier et al 2016), in order improve current thickness estimates of thick, extensive unconsolidated aquifer systems as well as, thin, smaller systems. Also, an improved estimate of conductivity will be made based on local available datasets. The second part of this research will focus on modelling using the global-scale model PCR-GLOBWB-MODFLOW (a hydrological model coupled to a groundwater model) to hydrologically evaluate the newly developed parameterization at the continental scale.

This project is part of larger project funded under the DAAD-PPP program together with researchers of IGE Grenoble, France. The French group will provide local data for hardrock aquifers and will be available for further discussion. A visit to Grenoble will be encouraged.

These projects require to apply and further develop skills and data processing and analysis (e.g. in R). Knowledge about hydrological modelling obtained during the MSc courses is needed. Programming skills and experience with Linux is not required. However, willingness to learn is a must. Also, an interest in global-hydrology is required.

English

First: Dr. Inge de Graaf (inge.de.graaf@hydro.uni-freiburg.de)

Second: Dr. Andreas Hartmann

MacDonald, A.M., H.C. Bonsor, B.E.O. Dochartaigh, R.G. Taylor, (2012), Quantitative maps of groundwater resources 
in Africa, Envirn. Res. Lett. 7, 024009 


Pelletier, J.D., P.D. Broxton, P. Hazenberg, X. Zeng, P.A. Troch, G-Y. Niu, Z. Williams, M.A. Brunke, D. Gochis (2016), A gridded global data set of soil, immobile regolith, and sedimentary deposit thicknesses for regional and global land surface modeling, J. Adv. Model. Earth Syst., 8, 41–65, doi:10.1002/2015MS000526

De Graaf et al. (2017), A global-scale two-layer global groundwater model, ADWR.