Erosion cycles of the past have been the prime determinant of watershed positions and river meanders. The mean annual rainfall determines runoff (flow) in river channels. In the east, the mountains of the Drakensberg and the Lesotho Highlands capture rainfall, giving rise to rivers such as the Komati, the Usutu, the Tugela and the Mzimvubu. To the west of the Lesotho Highlands, the Vaal and Orange Rivers drain westwards through areas of increasing aridity to reach the Atlantic Ocean at Oranjemund. In the south, the mountains of the Cape drain the winter rains to fill the Berg, Olifants and Breede Rivers.

In general, the runoff of most rivers originates from upper quaternary catchments in the watershed. There are, however, two noticeable exceptions: the Gouritz River in the Western Cape and the Blyde River in Mpumalanga. In the case of the Gouritz, the river originates on the escarpment behind Beaufort-West. The upper catchment is situated in an area of low rainfall (a so-called rain shadow of the Cape mountains) resulting in the lower catchments producing most of the runoff. The upper catchment of the Blyde River, which drains from the Mpumalanga Drakensberg, consists of the dolomitic rock formations with high groundwater yields. These yields result in a high, steady streamflow all year round.

 

What you can do to reduce solid waste Avoid the use of plastic bags as far as possible. Reduce the use of paper bags. Separate household waste. Use separate bins for biodegradable waste and non-biodegradable waste. Also separate recyclable items as far as possible, e.g. metal tins and cans, paper, glass bottles and plastic bottles. Sell recyclable items or deliver these at collection points. Use biodegradables for compost making. Reuse gift wrapping and containers. When you go out do not litter by throwing wrappings or similar items out of the car or minibus windows. Put these items into a public refuse bin or your own garbage bin at home.