Groundwater in Africa : is there sufficient water to support the intensification of agriculture from 'land grabs'?
MacDonald, Alan M.; Taylor, Richard G.; Bonsor, Helen C.. 2013 Groundwater in Africa : is there sufficient water to support the intensification of agriculture from 'land grabs'? In: Allan, J.; Keulertz, M.; Sojamo, S.; Warner, J., (eds.) Handbook of land and water grabs in Africa. London, UK, Routledge, 376-383, 488pp.Before downloading, please read NORA policies.
Large-Scale Land Acquisitions (LSLAs) or “land grabs” have over the last decade primarily focused on Africa. Of the top eleven countries that account for 70% of global LSLAs, seven (Sudan, Mozambique, Tanzania, Ethiopia, Madagascar, Zambia and Democratic Republic of Congo) are in Africa (Anseeuw et al., 2012). The total area of LSLAs in Africa is estimated to amount to 134 million hectares (Anseeuw et al., 2012). As the primary purpose of these LSLAs is agricultural including both food and non-food (e.g. biofuel) crops, a fundamental but unexplored hydrological assumption is whether the requisite water to sustain crop production exists. Indeed, this assumption underlies the accusation that “land grabs” are, in fact, “water grabs”. The question as to whether there exists sufficient water to sustain the intensification of agriculture in many parts of Africa is of importance to not only LSLAs but the proposed green revolution in Africa . The latter is a central platform of the poverty alleviation strategies of many African countries. Robust answers to the water supply question remain elusive. Limited hydrometric networks in Africa – as in many parts of the globe – commonly restrict both direct analyses of available freshwater resources and the validation of estimates derived from remote sensing (e.g. Swenson and Wahr, 2009) or macro-scale modelling (e.g. Vörösmarty et al., 2005). An additional complication is that Africa is home to the planet’s most variable rainfall and river discharge (McMahon et al., 2007) but national manmade capacities to store water (e.g. reservoirs) are among the lowest per capita in the world (Brown and Lall, 2006; Grey and Sadoff, 2007). As the world’s largest distributed store of freshwater, groundwater represents a potential source of water to enable the intensification of agriculture in Africa through irrigation. Indeed, dramatic increases in food production realised in South Asia and China since the 1970s have relied upon groundwater-fed irrigation. At present, only 5% of cultivated land in Africa is irrigated, well below the global average of 19.4% (Siebert et al., 2010). A key benefit of using groundwater in Africa is its slower response to changing meteorological conditions relative to surface water. As such, groundwater provides a natural buffer against climate variability (Calow et al., 1997; Calow et al., 2010). Furthermore, groundwater can be found in many environments so that sources can be sited close to the point of demand, minimising the requirement for extensive distribution networks (MacDonald and Calow, 2009). Groundwater is also commonly of suitable quality for agriculture though elevated concentrations of iron, fluoride or arsenic have been observed in some environments (Smedley, 1996; Edmunds and Smedley, 2005).. Indeed, across Africa, groundwater has already proved to be vital in providing safe drinking water to improve health and reduce rural poverty (Carter and Bevan, 2008; Hunter et al., 2010). Spatially explicit, quantitative information regarding available groundwater resources in Africa has, to date, remained extremely limited. In this paper, we discuss the availability of groundwater in Africa using results from new research and mapping (MacDonald et al., 2012). We also introduce some of the tools required to sustainably investigate and exploit the resource and the potential risks to groundwater and ecosystems from overuse and contamination of groundwater from intensive agriculture. A central question that these analyses seek to inform is where groundwater can sustain a green revolution in Africa without following the pathways of overexploitation and degradation that have occurred over much of Asia?
|Item Type:||Publication - Book Section|
|Programmes:||BGS Programmes 2010 > Groundwater Science|
|Additional Keywords:||GroundwaterBGS,Groundwater, Africa, agriculture, International development|
|NORA Subject Terms:||Hydrology
Agriculture and Soil Science
|Date made live:||06 Nov 2012 14:05|
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