The Grootfontein aquifer at Mahikeng, South Africa as hydro-social system

The Grootfontein aquifer is located about 20 km south east of Mahikeng, North West Province, South Africa, and currently supplies about 20% of Mahikeng’s water. Formed in weathered Malmani Subgroup dolomites, the aquifer contains good quality groundwater that could potentially supply more of Mahikeng’s water, as well as provide a strategic reserve of water for use during droughts. Over-abstraction of groundwater from the aquifer, mainly by irrigating farmers but also by the boreholes supplying Mahikeng, has caused the natural groundwater level to drop at a rate of about 0.4 m per year since the 1970s, leading to water level declines of as much as 28 m in parts of the aquifer. Although the Grootfontein aquifer is one of the best studied aquifers in South Africa hydrogeologically, efforts to address these declines since the 1970s have largely failed. This research combines hydrogeological evidence with social research (interviews and participant-observation) and the principles of Earth Stewardship Science to argue that the aquifer functions as a hydro-social system, and that institutional characteristics are the root cause of a collective inability to restore the aquifer to its full potential as a water resource. A sub-optimal and undesirable Nash equilibrium prevails, in which major groundwater users are unable or unwilling to reduce abstraction. The situation has significant cost and risk implications for the environmental, economic and social sectors, and contributes to insecurity, pessimism, inequality and mistrust. An effective local forum with appropriate powers, supported and mandated by the Department of Water and Sanitation, is needed to begin the work of dismantling the sub-optimal equilibrium to realise the potential of the Grootfontein aquifer. Such a forum would require a shared understanding of the hydrogeological mechanisms of the aquifer as well as its social and institutional functioning, since these influence each other in complex ways