Agricultural groundwater use in sub-Saharan Africa: What do we know and where should we go?

Relatively little is known about agricultural groundwater use and the agricultural groundwater economy of sub-Saharan Africa. However, available evidence suggests that the region's groundwater resources are substantial and greater in per capita terms than in some of the worlds' largest agricultural groundwater users including India and China. Nonetheless, calculations presented here also indicate that the direct contribution of groundwater to sub-Saharan Africa's agricultural economy is small, both in absolute and relative terms. Plausible explanations for low usage include physical geography, economics and economic policies, and politics. In addition to these real factors, incomplete information almost certainly contributes to an underestimation of agricultural groundwater use. Further, it is likely that ‘traditional’ approaches to groundwater valuation inherently miss some of the key groundwater functions in the sub-Saharan African context, in particular as they relate to livestock production and rainfall variability. While this paper supplies a baseline of information in some respects, much additional research is needed to improve our basic understanding of sub-Saharan Africa's agricultural groundwater use and importance, not only to help researchers and policy makers appreciate the value of the region's groundwater resources but also to provide a meaningful knowledge base on which development plans can be built. That said, the ultimate point of applied research should be to understand both where additional development in sub-Saharan Africa is possible and, equally important, where and why it is not.