The Río Grande de Tarija and Bermejo River in South America -

The Río Grande de Tarija and Bermejo River in South America

Today’s Image of the Day from NASA Earth Observatory features the Bermejo River and the Río Grande de Tarija, which flow through Argentina and Bolivia in South America. The photograph was captured by an astronaut onboard the International Space Station.

Meandering rivers

“The meandering rivers in this image are sourced in the Andes Mountains and generally flow southeast through valleys in the foothills – the region between the high mountains and plains. The Iruya River deposits particles of silt and clay as it flows into the valley centered in this image,” said NASA.

“Visible indications of the rivers’ shifting channels include river islands, point bars (on the inside curve of streams), and several meander scars. Such scars form when a river gets cut off from the main flow and fills in with sediment, soil, and vegetation.”

“Sediment from the adjacent highlands filled valleys that were formed by tectonic forces driving uplift of the Andes. These deposits are subsequently carried by rivers, such as the Iruya, along with new sediment to form the light-toned braided channels and the adjacent darker-toned floodplains. Nutrient-rich floodplain soils provide fertile ground for agricultural fields.”

Bermejo River

The Bermejo River originates in the Bolivian Andes and flows into Argentina. It plays a crucial role in the geographical and ecological landscape of the region. The river’s course is characterized by its meandering path through the Gran Chaco plain, making it a significant river in the region’s hydrological system.

Economic importance

The Bermejo River is vital for agriculture, providing essential water resources for irrigation. It also has potential for hydroelectric power generation.


The diverse habitats created by the Bermejo River, including its riverbanks, floodplains, and adjacent forests, support rich biodiversity. However, the wildlife in this region faces threats from habitat destruction, pollution, and climate change, making conservation efforts critical for their survival.

Jaguars are the apex predators of this region, and are occasionally spotted along the riverbanks, where they hunt. Large, herbivorous mammals called tapirs are found in the forests around the Bermejo River. They often visit the river to drink and cool off.

Capibaras, the world’s largest rodents, are commonly found in the wetlands and along the river edges.

Jabirus, the tallest flying birds in South and Central America, can often be seen in wetlands along the Bermejo River. Toco toucans, known for their colorful bills, can be found in the forested areas near the river.

Río Grande de Tarija

The Río Grande de Tarija, also known in its lower stretches as the Guadalquivir, flows primarily within Bolivia. It is a critical watercourse in the Tarija Department, contributing significantly to the region’s agriculture and livelihoods.

Economic importance

This river is essential for irrigation, supporting a variety of crops and contributing to the local economy. The surrounding lands are fertile and productive, thanks to the river’s water.


Similar to other rivers, the Río Grande de Tarija faces challenges such as water management issues, pollution, and the impacts of climate change on its flow and health.

Wildlife in Bolivian rivers

River basins in Bolivia are home to a wide range of bird species, including various species of herons, egrets, kingfishers, and perhaps even some rarer species like the wattled jacana or the sunbittern. The diverse birdlife is attracted to the abundance of fish and the relatively untouched natural habitats along the river.

The Characidae family includes many fish species that are commonly found in South American rivers, such as tetras. They are known for their diversity and are a key part of the river’s ecosystem, serving as both predator and prey.

Cichlids are another diverse group of fish that can be found in South American rivers. They play significant roles in their ecosystems as both predators and herbivores.

The rivers of Bolivia are also home to various catfish species, which are well adapted to life in muddy and turbulent waters. These include the armored catfish, which are often found clinging to rocks and logs.

Image Credit: NASA Earth Observatory/ ISS Crew Earth Observations Facility/ Earth Science and Remote Sensing Unit, Johnson Space Center


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