for National Geographic News
The underground water table in central Argentina's Monte Desert is falling, leaving the fate of the centuries-old indigenous Huarpes culture hanging in the balance (see pictures).
Demand for high-quality and still relatively inexpensive Argentine wine, combined with an abundance of land to grow grapes, has become a problem for the desert-dwelling Huarpes.
Vineyard owners are diverting increasing amounts of water from a network of channels and streams originally crafted for irrigation centuries ago by several of Argentina's indigenous groups.
The Monte Desert, where the indigenous people live, is separated from the Andes by Argentina's piedmont region, which has become the center of an expanding wine industry.
(See a map of the region.)
"People [here in the desert] live in a system that is harsh yet so far has survived because of one thing, and that's groundwater," said agronomist Esteban Jobbagy of Argentina's National University of San Luis.
"We are in an area where you can walk for days without seeing surface water, yet the aquifer is a source of life."
Jobbagy's research is trying to prove scientifically what some agronomists have begun to suspect—that rapid development between the Andes and the desert is putting pressure on the desert's aquifer.
Tracking the Water Table
Jobbagy is using ultrasonic telemeters to measure water levels at a series of wells in the region. Another tool, called a pressure transducer, obtains continuous measurements of the water table's depth.
Jobbagy and colleagues at Duke University's Nicholas School of the Environment and Earth Sciences in Durham, North Carolina have matched the isotopic signature—the unique molecular structure—of water formed by melting snow from the Andes Mountains to water collected in the desert's aquifer. The regions are separated by about 124 miles (200 kilometers).
The same water shows up in the stems of the Algarrobo tree, which has roots descending 32 feet (10 meters) from the desert floor to the aquifer.
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