Ground Water Security and Drought in Africa: Linking Availability, Access, and Demand

Abstract

Drought in Africa has been extensively researched, particularly from meteorological, agricultural, and food security perspectives. However, the impact of drought on water security, particularly ground water dependent rural water supplies, has received much less attention. Policy responses have concentrated on food needs, and it has often been difficult to mobilize resources for water interventions, despite evidence that access to safe water is a serious and interrelated concern. Studies carried out in Ghana, Malawi, South Africa, and Ethiopia highlight how rural livelihoods are affected by seasonal stress and longer-term drought. Declining access to food and water is a common and interrelated problem. Although ground water plays a vital role in buffering the effects of rainfall variability, water shortages and difficulties in accessing water that is available can affect domestic and productive water uses, with knock-on effects on food consumption and production. Total depletion of available ground water resources is rarely the main concern. A more common scenario is a spiral of water insecurity as shallow water sources fail, additional demands are put on remaining sources, and mechanical failures increase. These problems can be planned for within normal development programs. Water security mapping can help identify vulnerable areas, and changes to monitoring systems can ensure early detection of problems. Above all, increasing the coverage of ground water-based rural water supplies, and ensuring that the design and siting of water points is informed by an understanding of hydrogeological conditions and user demand, can significantly increase the resilience of rural communities to climate variability.

What impact will climate change have on rural groundwater supplies in Africa?

“…This increased demand is already observed in current climate variability, for example during droughts in southern Africa in the early 1990s (Calow et al, 1997) and more recently in the droughts in the Horn of Africa (MacDonald & Calow, 2007;Calow et al, 2009). In addition to these stresses, the ever-growing population across Africa puts considerable extra demands on individual sources.…”

“…Droughts are also endemic in Africa and the extent of drought-affected areas is increasing (Sheffield & Wood, 2008). Adapting to climate variability is therefore not new-and learning how water resources and people respond to existing variability is an important method for predicting possible future changes (Calow et al, 2009).…”

“…Boreholes are therefore drilled not only in aquifers with high storage, but also in poorer aquifers, where storage is limited and recharge is required annually (or at least every 2 or 3 years) to maintain reasonable yields. Therefore, any reduction in annual rainfall, changes in intensity or seasonal variations may cause problems for water supply, particularly in aquifers with low storage capacity (Calow et al, 1997(Calow et al, , 2009.…”

“…This is a problem of accessing the available groundwater resources, not a failure in the absolute groundwater availability. Different strategies can be used to help overcome this problem-for example, siting boreholes in more productive parts of the aquifer (Calow et al, 2009), adopting two-phase pumping (Holt & Rushton, 1984) and appropriate choice of technology (e.g. MacDonald et al, 2005a).…”

“…Continuing access to safe water generates major health benefits (Moore et al, 1993), supports food production and consumption (directly or indirectly), and reduces poverty (Carter & Bevan, 2008;Calow et al, 2009). In a global study of the costs and benefits of improved water supply and sanitation, WHO (2004) concluded that the wider socio-economic benefits of safe water and adequate sanitation ranged from US$3 to US$34 per US$ invested, with the highest returns in Africa; hence the international community's commitment to reduce by half those without safe water by 2015 (United Nations, 2000), as set out in the Millennium Development Goals (MDGs).…”