Over-abstraction

Despite there being large amounts of groundwater (approximately 0.66 million km³ across Africa (MacDonald et al. 2012)), we still need to be cautious about how much we can abstract sustainably, because over-abstraction of groundwater supplies can have detrimental social, economic and environmental impacts (Pavelic et al. 2013). Not only can over abstraction lead to depletion of groundwater reserves, it can also have other consequences such as land subsidence, saline intrusion and increasing costs of pumping, to name a few (Ogunba 2012, European Environment Agency 2016). Consequently, management is very important.

Agricultural irrigation is a major cause of groundwater over-abstraction (European Environment Agency 2016) and managing this is very difficult with the current trends in African farming leaning towards small-holder farming. Due to increasing access to low cost pumps and climatic variability, “groundwater irrigation for small holder farmers in SSA is growing in extent and importance” (Villholth 2013: 369). A higher number of individual users makes it more difficult to impose and enforce groundwater restrictions and/or monitoring to ensure sustainable abstraction (Knuppe 2011). Small-scale, rural farmers are also more likely to have conflict with management regulation than larger irrigation companies and projects, often holding traditional attitudes and expertise (Knuppe 2011). Couple this with a rather patchy and inadequate understanding of aquifer levels and behaviour, and it makes for rather difficult management.