The dividing line
Black water and brown.
Ana Claudia Jatahy - MTUR — CC0 · MTur Destinos — Public domain · Arne Müseler — CC BY-SA 3.0 de · MTur Destinos — Public domain
The Meeting of the Waters is a natural spectacle east of Manaus, where the dark Rio Negro meets the pale Solimões, as the Amazon is called in Brazil above this point, and the two flow side by side for about six kilometres without mixing: a sharp line between water black as tea and water brown as mud. The reason is the difference in temperature, speed and sediment: the Negro is slower and warmer, coloured by decayed plant matter, while the Solimões runs faster and cooler, laden with silt from the Andes. They go on mixing only partly for dozens of kilometres before becoming one river, the Amazon. It is seen on boat tours from the port of Manaus, usually half a day, and many combine it with Lake Janauari, giant water lilies and dolphin watching. The line is clearest from the boat, and you can dip a hand in each side to feel the difference in temperature.
Black water and brown.
Felt by hand.
At Lake Janauari.
Confluence of the Negro and Solimões, east of Manaus
Because of differences in temperature, speed and sediment: the Negro is warmer, slower and dark, the Solimões cooler, faster and silt-laden, so they run side by side for about six kilometres.