Under the gigantic and imposing Amazon river, considered the largest river on the planet, hides a secret that still surprises scientists today: An underground river flowing at a depth of about 4,000 meters. This impressive formation, called Hamza River, was identified in 2010 and flows silently under the states of Amazonas, Amapá and Pará, until it flows into the Atlantic Ocean.
Unlike the Amazon river we know, Hamza is not a river in the traditional sense of the term. It is in fact an aquifer, a geological formation made up of porous and permeable layers which store and transmit water. Despite this, his behavior is similar to that of a river: a source, a mouth, a continuous flow and even variations in flow.
Hamza represents a remarkable scientific discovery that widens our knowledge of water resources in the Amazon basin. It is a colossal underground system which covers a distance similar to that of the Amazon river itself – approximately 6,000 kilometers long – with a width varying between 1 and 60 kilometers.
Accidental discovery during a geothermal study
The revelation of this “invisible river” is the result of university work. The discovery was made during the doctorate of researcher Elizabeth Pimentel, of the Federal University of Amazonas (UFAM), in partnership with the Indian geophysicist and hydrogeologist Valiya Mannat Hamza – Honoré by the name of the aquifer. The study analyzed data on geothermal flows obtained from oil wells drilled by Petrobras in the 1970s.
During her research, Elizabeth identified unusual thermal anomalies in the region, which indicated the existence of an intense underground water. This research confirmed the existence of a water movement more than two thousand meters from the surface, configuring a real river.
According to the researchers, the origin of Hamza is at Acre. It is fueled by water infiltrations from precipitation and rivers in the basin, which penetrate deep into the sedimentary rocks of the region.
A slow but monumental course
Despite its size, the Hamza is an extremely slow river. Its flow speed is only 218 meters per year, against 5 meters per second for the Amazon river on the surface. This means that the Hamza moves about 40 times more slowly.
This difference in speed, combined with the depth and geological nature of the course, was fundamental to identify it as a distinct mass of water. Although invisible to the naked eye, The Hamza demonstrates the complexity and interconnection of the hydrographic network of the Amazon region.
The existence of Hamza Reinforces the importance of the Amazon not only as a surface ecosystem, but also as an underground reservoir of natural resources. It also raises new questions about how underground water systems interact with visible rivers in the region, climate and ecological cycles.
Article reference:
Portal The People. Amazon River can have ‘hidden’ watercourse: 4,000 meters deep. 2025
