Some rules of hydrology are made to be broken.
Some rules of hydrology are made to be broken. Two such infractions occur at junctions along rivers in Venezuela and Suriname, where the water flows in unexpected ways.
In Venezuela’s Amazonas state, the Río Casiquiare splits from the Río Orinoco as it flows gently through dense forest. Many rivers branch, or bifurcate, along their routes, and the branches almost always rejoin the main river channel. Not so with the Casiquiare. After veering south, it continues to meander off, flowing hundreds of kilometers until joining the Rio Negro and ultimately the Amazon River in Brazil.
The OLI-2 (Operational Land Imager-2) on Landsat 9 captured this image of the unusual river fork in March 2025. At first glance, one might assume that the Orinoco flows from west to east, with the narrower Casiquiare feeding into it from the south. But the reverse is true, and what appears to be a convergence is really a divergence. Some scientists think the split developed due to a combination of low topographic relief and high flow volume during floods.
Read more at NASA Earth Observatory
Image: NASA Earth Observatory images by Wanmei Liang, using Landsat data from the U.S. Geological Survey.
