Glaciers Go, Leaving Drought, Conflict and Tension in Andes

By Barbara Fraser, Daily Climate. Posted May 20, 2009.

Often, the scant water available is polluted. Three-quarters of wastewater in Peru is dumped untreated into rivers, lakes and the Pacific Ocean, and the Health Ministry has identified dozens of rivers polluted with lead, cadmium, arsenic, mercury and other metals from mining operations.

Need for efficient irrigation

In the Andes, these problems are exacerbated by demand for water for irrigation. About 80 percent of Peru's water goes to agriculture, and only 8 percent of farm land uses water-conserving systems like drip irrigation, according to Abelardo de la Torre, head of the new National Water Authority, which is overseeing the design of watershed management plans throughout the country.

The need for efficient irrigation will become critical within the next few decades, as ice caps disappear from the Andes, where most of the world's tropical glaciers are located, and where small farmers depend on meltwater during the dry season.

Outside La Paz, Bolivia, the Chacaltaya glacier, once billed as the world's highest ski resort, is nearly gone. And Ecuador plans to pipe water from the eastern side of the Andes to supplement the dwindling supply from two receding glaciers that provide Quito's drinking water.

In 1991, tropical Andean glaciers covered some 1,065 square miles, with 70 percent in Peru, 20 percent in Bolivia, and the rest in Ecuador, Colombia and Venezuela. Since then, glaciers have disappeared from Venezuela and are shrinking in the other countries. Calculations show a loss of nearly 10 percent per decade.

Ironically, the increased melting means a water bonanza now, but César Portocarrero, an engineer who helps small farmers install drip irrigation systems in Peru's Cordillera Blanca, named for its snow-capped peaks, said he has seen an increase in conflicts between neighbors and communities, which may be an early sign of water stress.

Impact on dams

It is not clear how much the loss of glacial runoff will affect drinking water supplies downstream. Experts say much of the decrease can be offset by expanding reservoirs to catch water during the rainy season.

But potable water will not be the only casualty. A World Bank study indicates that glacial melt it is likely to raise generating costs at hydroelectric dams on rivers fed by melt water.

Nevertheless, a hydroelectricity revival is underway in South America, especially in water-rich Amazonia. Not only will that add to the competition for water, but environmentalists worry that dams like the controversial project on the Madeira River in western Brazil will block the flow of nutrient-bearing sediments and fish migration routes.

Dams may also change the hydrological cycle in Amazonia, which affects precipitation in the Andes. Climate models and scientists do not agree on exactly what changes will occur in Amazonia. Some will depend on whether El Niño cycles are more frequent or intense. Researchers are handicapped by a lack of historical data from Amazonian countries.

"We know more now than we did 20 years ago, but we still don't know half of what we need to know," said José Marengo of Brazil's National Institute of Space Research in Sao Paulo.

"There are few studies and little meteorological data. There are huge data gaps in all the countries. In hydrological data, there are series of 20 or 30 years, when we would need 100 years or more to see if there is a cycle of flooding and drought."

Small farmers in the Andes, however, say there is already sufficient cause for alarm. Concerns over water shortages and salinization of pasture and crop land have spurred protests against large mines in Piura, in northern Peru, and near Oruro, in southern Bolivia, by farmers who say there is not enough water to go around.

A lack of planning

Meanwhile, the tension continues between export agribusinesses on Peru's southern coast and the small farmers upstream. Large-scale farmers on the coast have more efficient irrigation systems, but the profusion of wells is pumping water out of the aquifer nearly twice as fast as it can recharge, according to Javier Chiong of the Ministry of Agriculture in Ica.

Large farmers downstream are calling for a major infrastructure project to channel water from the highlands, dispersing some of it through canals in the desert to recharge the aquifer. Small farmers and llama herders upstream say the scheme could dry the Andean bogs, an ecosystem about which little hydrological data exist.

"There's a lack of planning," said Gotuzzo of the Farmers Association of Ica. "And it's the poor people who will suffer the most. The rich will be able to solve their problems."

See more stories tagged with: water, drought, water scarcity, andes, glaciers

Barbara Fraser is a journalist living in Peru.

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