Hydrologic impact of rewatering of the Gemsbokfontein dolomitic western subcompartment on the Wonderfonteinspruit, South Africa
Department of Geography and Environmental Studies, School of Environmental Sciences and Development, North-West University, Potchefstroom 2531, South Africa
The mean annual rainfall of South Africa is only about 450 mm. The unpredictability of the rainfall as well as extremely high potential evaporation result in the country being water stressed. It is predicted that the demand for water will outstrip the supply within three decades. In order to mitigate this problem, various huge transcatchment schemes have been constructed in South Africa and some of its neighboring countries, but these schemes will only postpone the drying up of the main rivers within a few years. For this reason, the importance of groundwater as a resource is increasing. South Africa does not have significant groundwater resources, although the dolomitic aquifers in the West and Far West Rand have a huge groundwater potential. These dolomites contain (under natural conditions) at least twice the volume of water of the Vaal Dam, which is the main water resource for the economic heartland of South Africa. Alkaline and mafic-alkaline dikes of Pilanesburg age divide the dolomites into several ground water compartments, which overlie some of the richest gold mines in South Africa. The mines have had an adverse effect on the groundwater potential, because most of the compartments have been dewatered to some degree to enable mining operations. Since some of the mines have reached the end of their life span, it is expected that some of the compartments will be allowed to rewater. The rate of rewatering is unknown and the research described in this paper was an attempt to model the rewatering of one of the compartments, namely the Gemsbokfontein compartment, in order to determine the time of rewatering as well as the eventual decant volume. Copyright © 2006 by V. H. Winston & Son, Inc. All rights reserved.
annual variation; aquifer pollution; dewatering; gold mine; groundwater resource; hydrological response; rainfall; water stress