Gariep Dam comparison

The Gariep Dam, the largest dam in South Africa, is featured in these Copernicus Sentinel-2 images captured on 30 January 2020. Visible in the bottom right, the Gariep Dam lies along the Orange River, bordering the Free State and Eastern Cape provinces. 

In this comparison, the image on the left shows the area in true colours, while the image on the right has been processed in a way that highlights vegetation in shades of green and water bodies in black. In the false-colour image the water on the east side of the dam appears in royal blue owing to a large quantity of sediments coming from the Orange River, therefore appearing brighter than the water flowing out of the west side of the dam.  

The Orange River is said to be one of the world’s most turbid, and is estimated to deliver around 60 million tonnes of sediment each year to the western margin of South Africa. A significant quantity of this sediment is believed to be from soil erosion, an increasing environmental threat to sustainability in southern Africa.