1. Jacqueline Goldin is with the Department of Earth Sciences, University of the Western Cape, Bellville, Cape Town, South Africa.
2. Resego Mokomela is with the Department of Earth Sciences, University of the Western Cape, Bellville, Cape Town, South Africa.
3. Thokozani Kanyerere is with the Department of Earth Sciences, University of the Western Cape, Bellville, Cape Town, South Africa.
4. Karen G. Villholth is with the International Water Management Institute, Pretoria, South Africa.