South America: Water deficits to shrink in Brazil but remain widespread & intense

23 July 2018

The 12-month forecast through March 2019 indicates significant water deficits in large pockets across northern Brazil, and many areas of moderate deficit elsewhere in the country and the continent. Deficits may be exceptional in the states of Amapá, Pará, Maranhão, Amazonas, and Acre, as well as farther south in São Paulo.

Significant deficits are also forecast for Guyana, Suriname, French Guiana, Venezuela, south-central Bolivia beginning near Cochabamba, northern Chile (Atacama Desert), and along the Chubut River in Patagonia.

Areas of surplus include: eastern Colombia into Venezuela; Huánuco Region of central Peru; Peru’s border with Bolivia and well into central Bolivia; central Paraguay; Brazil’s easternmost tip (Rio Grande do Norte); the Argentine Pampas and Neuquen, Argentina; and Patagonia surrounding O’Higgins/San Martín Lake and Rio Santa Cruz.

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

Though the extent of exceptional deficit will diminish in South America over the next several months, large pockets of intense deficit are forecast for Brazil in Acre, Rondônia, Pará, Tocantins, Goiás, western Minas Gerais, northern Mato Grosso do Sul, and São Paolo. Deficits are also expected to be intense along many rivers. Deficits of varying intensity are forecast for much of the remainder of the country.

A complicated patchwork of anomalies is forecast for the rest of the continent. Intense deficits are forecast for: Venezuela surrounding Caracas in the north; western Ecuador; along a dotted path from east of Lima, Peru through the Atacama Desert in Chile where both deficits and surpluses are expected as conditions change; and, the upper reaches of Río Chubut in Patagonian Argentina. Deficits in southern Bolivia will shrink and downgrade overall, and in neighboring Paraguay extreme deficits are forecast along the Río Paraguay in the center of the country. Deficits of varying severity are expected in many other regions.

Intense surpluses will persist in Peru’s Huánuco Region, and in Salta, Mendoza, and Neuquén Provinces in Argentina. Surpluses elsewhere include: far eastern Venezuela and across the border into northern Guyana; central and eastern Colombia and into Apure Province, Venezuela; southeastern Peru into central Bolivia; and, along the Río Salado in northwestern Argentina, the eastern Argentina Pampas, and southern Patagonia.

From October through December deficits will downgrade and diminish overall and surpluses will increase in central and southeastern regions of the continent. In Brazil, deficits will diminish in the nation’s southern two-thirds with conditions becoming moderate or even normal. In the northern states, however, severe deficits are expected along with pockets of exceptional intensity. Primarily moderate deficits are forecast for Peru, Ecuador, much of Colombia, and Venezuela, but deficits may be more intense in Guyana, Suriname and French Guiana, as well as in northern Chile. Moderate to severe surpluses are forecast for north-central Bolivia; along the Río Paraguay; and Argentina’s Iberá Wetlands, eastern Pampas, and southern Patagonia. Mild surpluses will emerge in Uruguay and neighboring Rio Grande do Sul, Brazil.

In the final quarter – January through March – severe to extreme deficits will increase in Brazil’s northern half, Suriname, French Guiana, and Chile. Surpluses will increase in Paraguay, Rio Grande do Sul, Brazil and northern Argentina.

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

Drought has contributed to Argentina's poor economic performance, leading to speculation that the country is entering a recession. Argentina’s economy shrank in April for the first time in over a year, as the agriculture sector dropped by 31 percent due to soy and corn crop failures. Argentine soy yields are at their lowest levels since the 2008/09 season, likely due to hot dry weather beginning in November, followed by heavy rains which halted harvesting in early April.

The Chilean avocado industry is at the center of contentions over water issues. Allegations abound in recent news that avocado production caused a regional drought, with accusations that producers were building illegal pipes to steal water supplies. Avocado growers deny the accusations and have made efforts to assure European customers, a heavy source of demand, that their product is grown fairly, refuting allegations published in a prominent British newspaper.

Heavy rains in eastern Colombia overflowed the Orinoco and Meta Rivers late last month, forcing the evacuation of 5,000 residents in the municipality of Puerto Carreño. A few days earlier, more than 4,000 people were affected by the Arauca River floods in Arauca Department when pressure caused the river to overflow a local dam, resulting in a 50-meter crack in a dike downriver.

The city of Lima, Peru is beginning to prepare for imminent water shortages as inadequate distribution systems strain to serve an expanding population amid a changing climate. Currently, roughly 1.5 million people have no access to running water and depend on deliveries of often-untreated water from private water trucks at exorbitant cost. The city’s water utility plans to invest almost $7 billion in new infrastructure, including the construction of a desalination plant south of Lima.

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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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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