By Uki Goñi
1 April 2018

Villa Mercedes, Argentina (The Guardian) – After a night of heavy rainfall, Ana Risatti woke to an ominous roar outside her home. Mistaking the noise for a continuation of the night’s downpour, she stepped outside to look.

“I nearly fainted when I saw what it really was,” said Risatti, 71. Instead of falling from the sky, the water she heard was rushing down a deep gully it had carved overnight just beyond the wire fence around her home.

The sudden appearance of a network of new rivers in Argentina’s central province of San Luis has puzzled scientists, worried environmentalists and disheartened farmers. It has also raised urgent questions over the environmental cost of Argentina’s dependence on soya beans, its main export crop.

“The roar was terrifying,” said Risatti, remembering that morning three years ago. “The land had opened up like a canyon. Water was pushing through as far as I could see. Huge mounds of earth, grass and trees were being carried along the water surface.”

The ravine that carved its way so dramatically across Risatti’s farm that night has by now grown 15-miles (25km) long. At its deepest point, it measures more than 60 metres wide and 25 metres deep.

The largest of several new water courses, the Río Nuevo (New river) runs through Cuenca del Morro, a groundwater basin with a mild incline covering 373,000 hectares (nearly 1,500 sq miles) of flatlands in the province of San Luis.

Alberto Panza, a 41-year-old cattle rancher, is one of the few holdouts refusing to lease his land to the giant soya-bean conglomerates that have largely replaced Argentina’s small farmers. He stands in front of a ravine that was carved by the 'Rio Nuevo', which appeared overnight in 2015 in Argentina’s central province of San Luis. Panza says, ‘This used to be totally flat pasture land.’ Photo: Uki Goñi / Guardian

Until the early 1990s, the Morro basin was a patchwork of water-absorbing forests and grasslands, but they are mostly gone, replaced by maize and soya beans.

Argentina’s transformation into a soya bean powerhouse has resulted in widespread deforestation to make way for the crop, which now covers of 60% of the country’s arable land. Some 2.4m hectares of native forest have been lost in the last 10 years, according to Greenpeace.

Esteban Jobbágy, an environmental expert at the University of San Luis, said the sudden appearance of new rivers was due to the convergence of three factors: “Number one, we have been going through rainy years in the recent past – climate has been changing. Next, the nature of the soils that we have here, which are quite unstable. And third, the fact that this watershed is hosting a lot of agriculture for the first time.” [more]

When nature says 'Enough!': the river that appeared overnight in Argentina

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