South America: Water deficits persist in Chile, surpluses forecast in Paraguay

September 20, 2016

The Big Picture
The forecast through April 2017, as seen in the 12-month map (below), shows pockets of exceptional water deficits (greater than 40 years) in Brazil’s Amazon Basin. Exceptional deficits are also forecast in the Cordillera Real Mountains in western Bolivia, the Gulf of Corcovado in southern Chile, and rivers in southern Argentina.

Brazil's robusta bean harvest is expected to fall 16 percent this season due to drought, says Confab, Brazil's crop forecasting agency, resulting in what could be the smallest harvest since 2006. Farmers in Espirito Santo, Brazil's top robusta region, are facing increasing water use restrictions and fear impacts not only on this season's production but next year's as well, with those trees currently in their thirsty flowering season.

In Mato Grosso, it's the soybean crop that has Brazilian planters worried. After significant losses last season farmers are cautious about premature planting, electing to delay until there's enough rain to restore soil moisture levels.

And in Chile, it's the vintners - five years of drought are threatening to reshape the country's wine-producing industry. Though 2016 has been wetter than prior years, some growers are pulling up vines and putting in walnut trees. The near-desert appellations of Elqui and Limarí have been particularly affected.

The larger landscape of Chile's privatized water structure is under increasing scrutiny from many Chileans who assert that it unfairly favors commercial use over human consumption. In a recent poll 74 percent of Chileans favored a return to public ownership of the nation's water supply, and a protest in Santiago attracted some 2,000 demonstrators.

Forecast Breakdown
The 3-month maps (below) for the same 12-month period illustrate the forecast of a transition in the second half of the period away from widespread exceptional deficits.

However, exceptional deficits are forecast across northern Brazil from September through November along with moderate (5 to 10 years) deficits reaching southward to Rio de Janeiro. Elsewhere on the continent, extreme (20 to 40 year) to exceptional deficits are forecast for: northern Venezuela surrounding Caracas; the Cordillera Real Mountains in western Bolivia; much of Chile, especially around the Gulf of Corcovado in the south; rivers in southern Argentina; Tierra del Fuego; and the Falkland Islands. Deficits of varying severity are forecast for northern Suriname, French Guiana, southern Colombia, Ecuador, Peru, and Bolivia. Surpluses are forecast in eastern Colombia, eastern Paraguay, Paraná and Santa Catarina in Brazil, the Paraná River Basin of northern Argentina, and throughout the Andes Mountains in western Argentina.  

The forecast map for December through February indicates a transition to less severe water deficits, with some exceptions. Severe (10 to 20 years) to extreme deficits are forecast to persist in Chile, the Cordillera Real Mountains in western Bolivia, rivers in southern Argentina, and Tierra del Fuego. Moderate to severe surpluses are forecast to persist in eastern Paraguay, and exceptional surpluses may persist in the Argentine Andes. Moderate surpluses are expected to emerge in northwestern Pará in northern Brazil; in a narrow west-east band across northern Paraguay; eastern Formosa, Argentina; and westward from Buenos Aires, Argentina.

The forecast for the latter months – March through May – shows a pattern similar to the prior three months.

(It should be noted that forecast skill declines with longer lead times.)


Many analyses reported in ISciences-authored blog posts are based on data generated by the ISciences Water Security Indicator Model (WSIM). Other sources, if used, are referenced in footnotes accompanying individual posts. WSIM is a validated capability that produces monthly reports on current and forecast global freshwater surpluses and deficits with lead times of 1-9 months at 0.5°x0.5° resolution. This capability has been in continuous operation since April 2011 and has proven to provide reliable forecasts of emerging water security concerns in that time-frame. WSIM has the ability to assess the impacts of water anomalies on people, agriculture, and electricity generation. Detailed data, customized visualizations, and reports are available for purchase.

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