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

24 August 2018

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

Significant deficits are also forecast in Venezuela, Guyana, south-central Bolivia beginning near Cochabamba, southern Peru, Chile (especially the Atacama Desert), and along the Rios Chubut and Chico in Patagonia.

Areas of surplus include: eastern Colombia; Huánuco Region of central Peru; Peru’s border with Bolivia and well into central Bolivia; central Paraguay; northeastern Argentina; the Argentine Pampas; central 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, Mato Grosso, northern Mato Grosso do Sul, and São Paolo. Deficits are also expected along many rivers. Deficits of varying intensity are forecast for much of the remainder of the country.

Exceptional deficits will diminish in Venezuela but intense deficits are expected across the north and in the southeast. Intense deficits are also forecast for: western Ecuador; sprinkled down western Peru; through most of Chile, with exceptional deficits in the Atacama Desert and Bío Bío; and, the Río Chubut in Patagonian Argentina. Deficits in eastern and southern Bolivia will shrink and downgrade, as will deficits in eastern Paraguay.

Surpluses will downgrade in central and eastern Colombia, but will be severe. Surpluses will shrink but persist with intensity in Peru’s Huánuco Region, and will persist in Salta and Neuquén Provinces in Argentina. Primarily moderate surpluses are forecast for southeastern Peru into central Bolivia; along the Río Salado in northwestern Argentina; and the Río Santa Cruz in southern Argentina.

From November through January deficits will downgrade overall, leaving moderate to severe deficits in the forecast for northern Brazil and its neighbors to the north. Deficits of similar intensity are forecast for southern Peru, but conditions in most of Chile will range from severe to exceptional, particularly in the north. Primarily moderate surpluses are forecast for northern Bolivia, central Paraguay, northeastern Argentina, parts of the Argentine Pampas, and southern Patagonia.

In the final quarter – February through April – the overall pattern will remain much the same as in the forecast for the preceding three months, but with surpluses expanding throughout eastern Paraguay into southern Brazil, Uruguay, northeastern Argentina, and farther south in the Pampas.

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

Venezuela’s rainfall this year is below average, exacerbating water shortages largely caused by mismanagement and decaying infrastructure. Under President Maduro, oversight of many lucrative industries including the water sector is in the hands of the Venezuelan military. A mere 27 percent of the population of the capital city of Caracas has access to continuous water service, while all others have to purchase at least some of their water supply. The military and police have seized control of the city’s public and private water trucks, as well as seven major water access points. In mid-July, a 12-year old boy was shot and killed during protests over water shortages and power outages. Caracas’ botanical gardens, a UNESCO World Heritage site, have been without water since March.

Tough drought which curbed Brazil’s sugar cane crop this year is already setting expectations even lower for next year’s cane. The Aracatuba region of São Paulo hasn’t had rain in three months, causing plantings in that area to be cancelled. If next year’s crop does shrink, next year will be the fourth consecutive reduction since a record harvest in the 2015/16 season.

Brazil’s northeastern state of Alagoas declared a state of emergency, as water shortages have affected more than 200,000 people. Tobacco and corn harvests in the area this year were dismal, and residential water tanks are coming up short in supply. Reservoirs in the northeast were averaging only 16 percent of capacity in July. Some experts blame regional development as a primary driver of desertification in the area.

Montane farmers in the Coquimbo region of northern Chile are utilizing externally-funded fog catching nets to boost water supply as precipitation becomes scarcer. Each 60-square-meter (646-square-foot) net costs $8,000 and can catch up to hundreds of liters of water per day. Coquimbo has been under a drought emergency since last December.

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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