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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

In 1998, South Africa promulgated a Water Act that is widely regarded as one of the most progressive and enabling pieces of environmental legislation in the world. The environmental aspects of the Water Act are commonly referred to as “resource-directed measures.” These measures attempt to find the right balance between (1) leaving water in the resource (“nonconsumptive use”) to provide ecological goods and services for society and (2) taking the water out of the system for “consumptive” human use. These measures also attempt to ensure that both nonconsumptive and consumptive use is sustainable. This article discusses some of the challenges faced in using the measures to achieve environmentally sustainable ground water use. A major challenge is that misunderstanding still abounds regarding the environmental aims of this legislation. Other major challenges identified included a severe shortage of technical capacity, an inordinately long water use license application process, incorporating adaptive management to deal with uncertainty, incorporating the public participation process, and revising policy implementation processes to accommodate highly localized aquifers. Selecting appropriate scientific methodology—neither too simplistic nor too involved—is a recurring challenge. It is suggested that an important part of addressing these and the other challenges identified is a period of reflection and dialogue between the various sectors involved.

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