Colombia’s Amazon River May Disappear, New Study Warns

Colombia’s Amazon river may disappear in the coming decades. That’s the alarming conclusion of a new study by Colombia’s National University (Universidad Nacional). According to researcher Juan Gabriel León’s findings, the share of the Amazon River’s flow transiting through Colombia has dropped from 30% in 1993 to just 19.5% as of June 2025.

The study shows that the Amazon River is gradually being diverted toward Peru, which now receives 81.5% of its flow. “As the current advances, it abandons the Colombian branch, where, for some reason—possibly due to sedimentation—the channels’ capacities are reduced, sending the entire water flow toward the Peruvian branch,” says Leon.

Colombia’s Leticia under threat, as the Amazon River diverts

This shift poses an urgent human and environmental threat to Colombia. Professor Lilian Posada García, from the Department of Geosciences and the Environment at the Faculty of Mines, warns that “since 2012, the river has been drifting away from Leticia,” the capital of Colombia’s Amazon region, located in a tri-border zone with Brazil and Peru.

Researchers warn that Leticia, which depends on the river, could be completely cut off from the Amazon by 2030. This is due to the waters of the Estrecho de Nazaret, where the river divides, increasingly flowing toward Peru and less toward Leticia.

“Border landmarks like the one at Atacuari, which once marked the binational frontier, no longer exist,” Posada notes. “The forecast is clear: if immediate action isn’t taken, Leticia will cease to be a riverside city. The implications go beyond symbolism—they’re cultural, economic, and territorial.”

According to Posada, the root problem is institutional inaction, despite decades of warning signs. “The core issue,” she insists, “is institutional inaction. The Navy must sound the alarms. Political and diplomatic decisions have been absent, even though the Amazon is a living and strategic border. The environmental consequences are also severe,” she warns.

Since 2006, Colombian researchers have proposed dredging and the installation of submerged groynes to counter the river’s retreat, yet authorities have not responded.

“The Yahuarcaca lake system, which is fundamental to global biodiversity and hydrological balance, could dry up if the Amazon River stops feeding it,” Posada warns.

One of the major risks is the desertification and drying of the region—a serious threat to local communities and biodiversity. “The consequences are grave. Many Indigenous communities rely on fishing in lakes like Yahuarcaca, which have extremely high productivity. If the river drifts away, those fish will no longer arrive and fishing will disappear. These communities would have to completely transform their amphibious culture,” she explains.