South America: Intense water deficits to persist in Chile & large pockets of Brazil

26 September 2018

THE BIG PICTURE
The 12-month forecast through May 2019 indicates significant water deficits in large pockets across northern Brazil and moderate deficits throughout much of the rest of the country. Deficits may be exceptional in Pará, Maranhão, and Mato Grosso, as well as farther south in São Paulo. Significant deficits are also forecast for Venezuela, Guyana, Suriname, and French Guiana.

Moderate deficits are forecast for central Peru with more intense deficits in the south. Extreme to exceptional deficits are expected throughout much of Chile; along a path in south-central Bolivia beginning near Cochabamba; and along the Ríos Chubut and Chico in Patagonia.

Areas of surplus include: central Colombia; Huánuco Region of central Peru; central Bolivia; central Paraguay; Uruguay; northeastern Argentina; the Argentine Pampas; central Neuquen, Argentina; and Patagonia surrounding O’Higgins/San Martín Lake and Río Santa Cruz.

FORECAST BREAKDOWN
The 3-month maps (below) for the same 12-month period show the evolving conditions in greater detail.

Though the extent of exceptional deficits will diminish considerably in Brazil over the next several months the forecast through November indicates intense deficits across the north, including a pocket of exceptional deficit in Pará surrounding the Río Trombetas, and moderate deficits throughout much of the remainder of the country. Deficits remain in the forecast for Brazil’s northern neighbors as well – Venezuela, Guyana, Suriname, and French Guiana – and are expected to be severe to exceptional in northern Venezuela from Caracas leading southeast. Scattered, intense deficits are forecast in western Ecuador, along a path through western Peru, and in Peru’s Ucayali Region. Intense deficits will increase in Chile, spanning a vast stretch from the Atacama Desert in the north, past Santiago, and through Bío Bío. Deficits in southern Bolivia will downgrade to primarily moderate but may be more intense along portions of the Río Grande and around Potosí. Extreme deficits will persist on the Río Chubut in Patagonian Argentina, and severe deficits are forecast for the Ríos Chico and Negro and the lower Río Colorado.

Surpluses will persist but moderate in central Colombia, downgrade from exceptional to severe in Peru’s Huánuco Region, and shrink in southeastern Peru into Bolivia. In Argentina, moderate surpluses will persist in Entre Ríos and Buenos Aires Provinces, some intense surpluses along the southwest border of La Pampa Province into Neuquén Province, and intense surpluses along the Río Santa Cruz in the south and nearby O’Higgins/San Martín Lake.

From December through February Brazil’s northern half will see moderate to severe deficits, with deficits reaching extreme intensity in northeastern Pará into Maranhão. Deficits are also forecast for Brazil’s northern neighbors and may be extreme in French Guiana. Surpluses in central Colombia will transition to mild deficits with moderate deficits to the north and south. Western Ecuador will transition from deficit to moderate surplus. Deficits will persist along coastal Peru, and moderate to extreme deficits will spread in central and southern regions of the country. Surpluses will spread in central Bolivia and deficits in the south will intensify. Moderate surpluses are expected to emerge in central Paraguay; Rio Grande do Sul, Brazil; and Uruguay. Surpluses will increase in northeastern Argentina and in the Pampas, where conditions may be severe. Deficits of varying intensity are forecast in southern Argentina between the Ríos Colorado and Chico. Exceptional deficits will persist in northern Chile; primarily severe deficits are forecast in the south but may be exceptional near Santiago.

In the final quarter – March through May – deficits are forecast for central and eastern Brazil, and Peru, southern Bolivia, and Chile. Widespread surpluses will emerge across central Venezuela, and surpluses will increase in Paraguay, southernmost Brazil, Uruguay, northeastern Argentina and the Pampas.

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

IMPACTS
The northeastern Brazilian state of Alagoas declared a 180-day state of emergency due to water shortages that have affected more than 200,000 people. In addition to the region experiencing a drought from 2012-2017 that was its worst since 1980, experts blame regional development for rapid desertification in the northeastern region of Brazil.

In what’s seen as a relatively new strategy for Chile, the federal government is implementing major restrictions on water extraction permits to lithium producers to cut overexploitation of dwindling groundwater resources in the Salar de Atacama, a large salt flat within which lithium is typically extracted from brine.

“Mega drought” and the conversion of native forests to flammable pine and eucalypt tree plantations have been shown to be driving larger and more intense wildfires in south-central Chile, according to research published late last month. The non-native plantation forests - which supply pulp and timber mills that make paper and wood products - provide ready fuel for the fires in what has become a hotter and drier climate.

Drought caused forecasts for Argentina’s 2017-2018 oilseed crop to drop 37 percent from estimates issued at the beginning of the year. In 2016 Argentina lifted an import ban to begin using Paraguayan soybeans to support its crush industry. This year’s low domestic crop outlook has forced Argentina to expand imports to include Brazil and the United States.

Heavy rain disrupted water service in northern Trinidad last month by causing turbid river conditions, clogged intake screens and power failures.

NOTE ON ADMINISTRATIVE BOUNDARIES
There are numerous regions around the world where country borders are contested. ISciences depicts country boundaries on these maps solely to provide some geographic context. The boundaries are nominal, not legal, descriptions of each entity. The use of these boundaries does not imply any judgement on the legal status of any territory, or any endorsement or acceptance of disputed boundaries on the part of ISciences or our data providers.

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