Authors of the article are affiliated with the British Geological Survey and University College. They provide a continental analysis highlighting the location and extent of Africa's vast underground water reservoirs. They emphasis that large-scale drilling is not necessarily the best way to access these hidden resources. First, there is a need to understand local conditions and then develop boreholes for low yielding rural water supply and hand pumps. Otherwise, the aquifers might be depleted very rapidly. They were probably last filled 5,000 years ago and are not replenished by any type of seasonal rainfall.
Data for the map and publication was collected from 283 existing national government hydro-geological maps and aquifer studies. These demonstrated that certain countries designated as "water scarce" are in fact, the location of large-scale underground water reservoirs. The largest of these are in northern Africa, in sedimentary basins in Libya, Algeria and Chad. Across the continent, groundwater reservoirs may provide a needed boost to supplement the development of new irrigation systems. Currently, only five percent of land in Africa is irrigated.
Authors of the study caution that the water in these underground reservoirs must be utilized carefully. Even with careful local community usage, they could provide a buffer in areas of little rainfall for only approximately 20 to 70 years.