A Potential Underground Solution to Africa's Water Shortage

A newly discovered aquifer may help solve water shortages
The Etosha Pan at Etosha National Park, Namibia Photograph by Paul Souders

Relief may be coming to the driest nation in southern Africa. The discovery of a 10,000-year-old supply of water in an underground aquifer in northern Namibia, near the border with Angola, could potentially reshape the developing nation’s ability to cope with the effects of climate change and rising population. Lying about 300 meters below the sub-Saharan surface and beneath layers of salt water and hard rock, the fresh supply is cleaner than most of the region’s surface water today. According to geologists, it could satisfy northern Namibia’s basic drinking and irrigation needs for 400 years.

The discovery in July by German scientists, estimated to cover an area 43 miles by 25 miles, is just the latest phase in an ongoing redefinition of Africa as an exceedingly dry continent. Last April the British Geological Survey and researchers from University College London reported that throughout Africa, the amount of underground water is more than 20 times the volume on the surface. With a population expected to exceed 2 billion people by 2050, the developing economies of Africa are particularly susceptible to the effects of climate change, as lack of rainfall and increasing temperatures evaporate the lakes and rivers that were the traditional sources of fresh water for rural communities.

“[Three hundred] million people [in Africa] still do not have access to safe drinking water,” wrote Alan M. MacDonald, principal hydrogeologist at the British Geological Survey and lead author of the continent-wide survey.  “Groundwater therefore has great potential to improve health and help people move out of poverty.”

Most of the aquifers are found in the sedimentary basins of northern Africa, with high concentrations in Libya, Algeria, and Egypt—countries that, in general, have fewer clean-water shortage problems to begin with. But scientists estimate that if used efficiently, there should be enough to satisfy at least the basic needs of all. “The great thing about groundwater is that usually small volumes can be found close to where it is needed. … [T]here is generally enough groundwater within reach of most African communities to develop for drinking water,” wrote MacDonald. For some of the most vulnerable communities in rural sub-Saharan Africa, this would involve drilling a borehole about 50 meters deep and setting up a hand-pump system to allow low-yield use for drinking and basic agriculture. Such an arrangement would cost around $6,000 per well, according to MacDonald. Larger, higher-yielding basins have the potential to supply urban and industrial areas, but at a much higher cost and greater risk of overuse.

With demand for water expected to grow dramatically in coming years as lack of rainfall coincides with a population boom, many believe that the single greatest potential source of conflict among states is control over water resources. Even today, only a small fraction of arable land in Africa is actually irrigated; a lack of infrastructure and diminishing surface supplies often lead to crop failure and resulting malnourishment.

But the danger of overuse cannot be underestimated while there’s a temptation to quickly tap into reservoirs for intensive irrigation and urban supply, especially when many of the aquifers are thousands of years old and are not recharged by rainfall today. “The groundwater was laid down more than 500 years ago when the climate was wetter,” MacDonald points out. ”So any use of groundwater now in those regions should be considered as mining fossil water.” A further reason to proceed with great caution is that many of the freshwater aquifers lie beneath saltwater deposits, and drilling too fast might cause the supplies to become mixed, compromising the drinking integrity of the fresh basins. The actual process of abstraction will probably be the province of the various African governments, working in conjunction with a multitude of NGOs such as Unicef and WaterAid.

Back in Namibia, where prior to the recent underground discovery the Cunene River shared with Angola had been the only significant source of drinking water for the country’s northern inhabitants, government officials are cautiously optimistic. Abraham Nehemia, undersecretary for water and forestry in the Agriculture Ministry, told AFP: “If the underground water reservoir is indeed there, it would be a relief for the supply of potable water in northern Namibia.” There is also a belief that some of the water can be transported to other parts of the country, if done so economically.

With economic growth in sub-Saharan Africa still robust, despite global economic turmoil, and with output expected to increase further in 2012, many have worried that the levels of development driven largely by strong commodity prices will be unsustainable without the most basic resource available in sufficient abundance. The recent discoveries would seem to go a long way toward assuaging that fear, assuming that the results are verified and that sustainable methods of extraction are utilized. As explained by MacDonald from the BGS: “Often the global water-scarcity maps miss out groundwater and therefore give you a skewed view of how dry Africa is. By adding groundwater storage back in, you get a truer picture of the available freshwater resources.”

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