There have been many studies of groundwater recharge across Africa. These vary significantly in terms of the study scale; the geographical, climatic and geological characteristics of the region of interest; the quality of data used; and the estimation methods applied.
Global Recharge Estimates
At a global scale, Döll and Fiedler (2008) provide estimates of long term average diffuse groundwater recharge based on the WaterGAP Global Hydrology Model. The model is run with a daily time-step at a spatial resolution of 0.5°, and is driven by gridded precipitation data. Model parameters are adjusted to match observed long-term average river discharge at more than 1000 gauging stations around the world.
Doll P & Fiedler K. 2008. Global-scale modelling of groundwater recharge. Hydrol. Earth Syst. Sci. 12, 863-885. doi:10.5194/hess-12-863-2008.
Overview of Recharge Studies in Africa
Bonsor and MacDonald (2010) reviewed around 100 recharge studies from across the continent and ranked each study according to a set of confidence criteria. They summarise the applicability of the following estimation techniques for different geographical settings applicable to Africa:
- Chloride mass balance
- Water balance methods
- Water table fluctuations
- Groundwater residence times
- Groundwater modelling
Bonsor HC & MacDonald AM. 2010. Groundwater and climate change in Africa: review of recharge studies. British Geological Survey Internal Report (IR/10/075)
An UPGro catalyst project, finished in 2014, investigated groundwater recharge in Africa: identifying critical thresholds.