What’s the Blue Nile and the White Nile?

Blue Nile and White Nile are two tributaries of the Nile that flow from the South into what is referred to as the Nile proper, the longest river in the world. While the White Nile is the longer tributary, the Blue Nile is the main source of water and fertile soil. The White Nile is called so because of the light coloured clay sediment in the water giving the river a light grey colour. The Blue Nile flows for about 1,400 km to Khartoum from Lake Tana which is 1,800 metres above sea level in the Ethiopian mountains. The White Nile and Blue Nile merge near Khartoum, becoming Nile proper.