1 HOW MUCH GROUNDWATER DOES SOUTH AFRICA HAVE?

This is a question that, until recently, hydrogeologists could not answer, much to the frustration of water engineers and planners, not to mention hydrogeologists themselves. In 1998, the so-called ‘Harvest Potential ’ (HP) map of South Africa was produced using information from a national hydrogeological mapping project completed in 1995, where it was estimated that 19,000 Mm3 of groundwater could be abstracted on an annual basis. In 2001, the HP map was revised to take into the highly variable permeability within and between the various aquifer systems and the available groundwater resources was down-scaled to only 10,000 Mm3/a. In late 2003, the Department of Water Affairs and Forestry (DWAF) initiated the Groundwater Phase 2 Project, which is aimed at the quantification of the groundwater resources of South Africa on a national scale. The project has been carried out by a consortium of consultants with SRK Consulting as project leaders in close collaboration with key DWAF personnel and was completed in June 2005. Algorithms have been developed for the estimation of aquifer storage, recharge, baseflow and the groundwater reserve. The quantities derived for the key aspects of recharge, aquifer storage and extractable groundwater are 30,520, 235,500 and 19,000 Mm3/a, respectively