Soil erosion is a process that is widespread in the Karoo landscape where deeply incised ‘dongas’ and dense gully networks known as badlands can be seen in many areas. Soil erosion is associated with a low density of vegetation cover, which is often blamed on overgrazing by livestock. Erosion results in soil being lost from the hillslopes, reducing the soil’s ability to support a good vegetation cover. The soil may be deposited elsewhere in the landscape, or in extreme rainfall events, can be carried into rivers and deposited in farm dams and reservoirs. This eroded soil is known as sediment. As the sediment is deposited in farm dams, it reduces their capacity to trap water for use during dry periods for stock watering and irrigation. This is a serious problem for the farmer, but provides an interesting opportunity to study the history of soil erosion in the catchment area from which the sediment has come.
A group of geomorphologists (scientists who study landscape processes such as soil erosion) have been doing research on farm dams in the Sneeuberg area, turning the sediment trapped there into a history book of landscape processes. South African researcher Professor Kate Rowntree from Rhodes University, Grahamstown, has been working with four researchers from England and Scotland, Professor Ian Foster from Northampton University, UK, Dr John Boardman from Oxford University, Professor Tony Parsons from Sheffield University and Dr Tim Mighall from Aberdeen University. Their research findings are beginning to tell us more about the history of land degradation and soil erosion in the Sneeuberg area of the Karoo.
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