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Underground river 'Rio Hamza' discovered 4km beneath the Amazon
Scientists estimate the subterranean river may be 6,000km long and hundreds of times wider than the Amazon
Alok Jha, science correspondent guardian.co.uk
Friday, 26 August 2011




Covering more than 7 million square kilometres in South  America,  the  Amazon  basin  is  one  of  the biggest  and most  impressive  river  systems  in  the world. But it turns out we have only known half the story until now.

Brazilian  scientists  have  found a  new  river  in  the Amazon  basin  –  around  4km  underneath  the Amazon  river .  The Hamza  river ,  named  after  the head  of  the  team  of  researchers  who  found  the groundwater  flow,  appears  to  be  as  long  as  the Amazon  river but up  to hundreds of  times wider . Both  the Amazon and Hamza  flow  from west  to east and are around the same length, at 6,000km. But whereas the Amazon ranges from 1km to 100km in width, the Hamza ranges from 200km to 400km. The  underground  river  starts  in  the  Acre  region under the Andes and flows through the Solimões, Amazonas and Marajó basins before opening out directly  into  the depths of  the Atlantic Ocean.

The Amazon  flows much  faster  than  the Hamza, however ,  draining  a  greater  volume  of  water . Around 133,000³m  of water  flow  through  the Amazon per second at speeds of up  to 5 metres per second. The underground river's flow rate has been estimated  at  around 3,900³m   per  second  and  it barely  inches along at  less  than a millimetre per hour .

The Hamza was located using data collected inside a series of 241 abandoned deep wells  that were drilled in the Amazon region by the petrochemical company  Petrobras  in  the  1970s  and  1980s. Elizabeth Tavares Pimentel and Valiya Hamza of  the Department  of  Geophysics  at  Brazil's  National Observatory  led  the  work  and  presented  their results  last week at  the  International Congress of  the Brazilian Geophysics Society  in Rio de  Janeiro.

According to the researchers, the presence of the Hamza  river might  account  for  the  relatively  low salinity  of  the  waters  around  the  mouth  of  the Amazon.  Professor  Hamza  said  Pimentel's measurements represented preliminary work on  the discovery  of  the  new  river ,  but  Hamza  said  he expected to confirm the existence of the flow with additional measurements within  the next  few  years.

No trecho do segundo parágrafo - But whereas the Amazon ranges from 1km to 100km in width, the Hamza ranges from 200km to 400km. - a palavra whereas pode ser substituída, sem alteração de sentido, por