South America: Widespread water deficits in Brazil to persist but moderate

21 September 2017

The Big Picture
Water deficits are forecast for much of Brazil north of Rio for the 12-month period ending May 2018, with large pockets of exceptional deficits in Mato Grosso, Tocantins, Amapá, and western Amazonas. Deficits reaching exceptional severity are also forecast for northwest and southern Venezuela, French Guiana, and Cochabamba, Bolivia.

Surpluses are expected in Buenos Aires and La Pampa Provinces, Argentina, and in southern Patagonia.

Impacts
As of the end of August, Brazil's capital city, Brasilia, has gone 120 days without rain, the longest dry spell since 2010. Water rationing has been in place since January in the Federal District where Brasilia is located, allowing a 48-hour period of normal water supply followed by a 24-hour interruption. With drought negatively impacting the nation's hydroelectricity production, the government plans to increase imports from Uruguay and Argentina.

In the nearby State of Minas Gerais, at least 25 municipalities are under water restrictions, including Montes Claros, a northern city of 400,000 residents. The north of Minas Gerais has always been arid but the situation has become more complicated due to low rainfall, eucalyptus monoculture, and unrestrained use of tube wells. Hopes for a bumper coffee crop are fading as reservoirs are even too low for pumps to supply irrigated fields.

Low levels on the Tocantins River have prompted the State of Pará to institute water rationing in the southeastern twin cities of Nova Marabá and Cidade Nova, who will alternate use of the water supply every 12 hours.

Water restrictions are also in place in the States of Espírito Santo and Rio de Janeiro.

The cost to rebuild infrastructure in northern Peru where massive flooding occurred earlier this year will total 25.65 billion soles (US $7.92 billion) according to updated government calculations, about 28 percent higher than previously estimated. Pablo de la Flor, head of the reconstruction effort, called it "the most important fiscal effort in Peru's recent history."

Argentina is poised to return to a spot in the top 10 beef exporters after a nearly decade-long recovery from drought-induced herd liquidation that dropped its 2010 cattle count to the lowest since 1964.

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

Noticeable at a glance in the map progression is a transition from reds and oranges through November – indicative of water deficits – to some green and blue tones showing surplus conditions in the latter half of the forecast.

In the near-term, however, widespread deficits remain in the forecast for much of the continent, particularly Brazil. Deficits in Brazil are expected to moderate through November though more intense deficits will continue to emerge in the far north and into Suriname and French Guiana, and in the far east in coastal Ceará and Rio Grande do Norte. Intense deficits are also forecast during this period for north-central Venezuela near Caracas, and southern Venezuela; Cochabamba, Bolivia; northern Chile; and Tierra del Fuego. Severe to extreme surpluses will persist in La Pampa and Buenos Aires Provinces in Argentina, but only small pockets of exceptional intensity are expected. Moderate surpluses will emerge in Uruguay and continue to emerge across the border into Argentina.

In the December through February map the emergence of widespread surpluses of moderate to severe intensity is evident in the northern Amazon Basin into northern Peru, Colombia, southern Venezuela, northern Guyana, and Suriname. Surpluses trace paths along the Amazon, Negro, and Orinoco Rivers. Surpluses are also expected to emerge in northern Bolivia, eastern Paraguay into southern Brazil, and will persist in Buenos Aires Province, Argentina. Deficits in Brazil will retreat to the east but will increase in intensity reaching extreme or even exceptional severity in Bahia and Pernambuco. Deficits will also be intense in a pocket of northeastern Roraima and into southern Guyana, and will emerge near La Paz, Bolivia.

The forecast for the final months – March through May – indicates the persistence of moderate surpluses in the northern Amazon Basin.

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

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