Hamza River

The Hamza River (Portuguese: Rio Hamza) is a recent discovery. Under the ground in the Amazon area is a huge slowly moving waterway. This slowly flowing aquifer in Brazil is about  long. It is nearly   below ground level. Its discovery was announced in 2011. The Hamza "river" and the Amazon River are a twin-river system flowing at different levels of the Earth's crust.

Description
The Hamza and the Amazon are the two main drainage systems for the Amazon Basin. The reported flow rate of the Hamza, at about  per second, is 3% of the Amazon's. It runs west to east, some  below the Earth's surface, and follows roughly the path of the Amazon River. The Hamza empties in the Atlantic Ocean, deep under the surface. Its own water has a high salt content.

It flows from the Andean foothills to the Atlantic coast in a nearly west-to-east direction like the Amazon River. Seismic data and temperature variation with depth measured in 241 inactive oil wells helped find the aquifer.

Except for the flow direction, the Amazon and the Hamza have very different characteristics. The most obvious ones are their width and flow speed. While the Amazon is  to  wide, the Hamza is  to  in width. But the flow speed is   in the Amazon and less than  speed in the Hamza.

Geology
Several geological factors have played a vital role in the formation and existence of these subterranean water bodies. Water has worn away calcium carbonate rocks far under the ground. Water drops to great depths. East-west trending faults and the karst topography  may have some role in supplying water to the "river".

The 153 km-long underground river in Mexico's Yucatán Peninsula, and the 8.2 km-long Cabayugan River in the Puerto Princesa Subterranean River National Park in the Philippines have come into being thanks to the karst topography. Water in these places has dissolved the carbonate rock to form  extensive underground river systems.

 References 

Category:Rivers of Brazil