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The purpose of this paper is to investigate whether a simple, spatially-based approach to groundwater sustainability using radius of influence should be used to replace the pervasive, yet deprecated, ‘natural recharge water balance’ volumetric method. Using South Africa as a case study, the radius of influence methodology was shown to be scientifically practical, to provide plausible results, and to be permissible under the country’s water laws. The approach also provides better indicators for institutions involved in groundwater management, and remains conceptually correct at all scales. However, further research is recommended on more robust alternatives to the Cooper-Jacob equation for determining radius of influence. Keywords : groundwater, sustainability, spatial, water balance, indicators, institutions

The purpose of this paper is to review the case for using ‘capture\' rather than recharge as the conceptual basis for sustainable groundwater use in South Africa. Capture refers to the sum of the increase in recharge and decrease in discharge brought about by pumping. Definitions of sustainability are reviewed, and the capture process is outlined. Implications for using the capture principle in the implementation of the NWA are discussed, and adaptive management is proposed as an appropriate management approach. Implications for groundwater monitoring are also discussed. Case studies are described that support the need for adaptive management and the application of the capture principle. Water SA Vol.32 (4) 2006: pp.473-482