with permission of Dr Alexandra Parker : 25 September 2017
The Gauteng City-Region Observatory (GCRO) has published the August 2017 Map of the Month showing the watershed* boundaries of the Gauteng Region. These important boundaries show the significance of the Gauteng region as the origin of three major river systems in South Africa, being the Vaal River, the Olifants River and the Limpopo River. This means that pollution from Gauteng can be conveyed all the way to the Indian or Atlantic Oceans.
Next time you see a plastic bag or bottle lying around, remember that it could find its way to the middle of the ocean or perhaps become wrapped around a sea turtle or eaten by seabirds.
*The Gauteng City-Region sits at the top of an escarpment that * functions as a continental drainage divide or watershed. This divide, shown by the red line in the map, runs through Randfontein in the West via the gold mining belt of Krugersdorp, along the Northcliff Ridge, onto Braamfontein, through Kensington, over OR Tambo airport and north of Benoni. Rain that falls to the south of the watershed flows into the Vaal River and eventually out into the Atlantic Ocean via the Orange River.Rain that falls north of the watershed flows into the Indian Ocean via the Limpopo River system. The watershed line shown in green on the map separates the Crocodile River to the west from the Olifants River to the east,both of which are tributaries of the Limpopo River.