Meeting of the Waters in Manaus

In Manaus, the lighter water from the Rio Solimões will meet the darker water from the Rio Negro. This is called the meeting of the waters or in Portuguese, “Encontro das Águas.” The new combined river is known as the Amazonas. However, the lighter water from the Rio Solimões does not immediately mix with the dark water from the Rio Negro. You can see the line that separates the two different types of water even thought hey join to become the Amazonas. This line can even be seen from space. This is a major attraction in Manaus and many tourists come here to see this phenomenon.

This phenomenon where the water from the Rio Solimões and Rio Negro won’t mix is because the water coming both have different velocities, temperatures, and different dissolved sediments. Compared to the Rio Negro, the Rio Solimões generally flows faster and has a lower temperature. Also, the Rio Solimões is lighter in color because it carries rich sediment from the Andean mountain. You can see below what the Rio Solimões looks like before it combines with the Rio Negro:

On the other hand, the Rio Negro flows at a slower rate and has a higher temperature than the Rio Solimões. The Rio Negro also carries decayed vegetation and the acidic level is a little higher. The decayed vegetation gives the Rio Negro a darker color before it joins the Rio Solimões. For these reasons, the waters from the two different rivers do not mix very well. You can see the darker color of the Rio Negro before it joins the Rio Solimões below: