South America: Widespread water deficits to persist in Brazil

21 April 2021

THE BIG PICTURE
The 12-month forecast through December 2021 indicates intense water deficits in much of Brazil south of the Amazon River from Acre in the west through the nation’s eastern tip, and from Amapá in the north through Mato Grosso do Sul. Deficits will be exceptional in many areas and along many rivers.

Exceptional deficits are also forecast along the Paraguay River through its namesake and along the Paraná River through Brazil, Paraguay, and Argentina.

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Across the northern arc of the continent, intense deficits are expected in a belt from Colombia’s northern Pacific Coast through Medellin to the Venezuelan border, and in the southeast reaching into Brazil. Deficits will be severe along Venezuela’s central coast and even more intense around Merida in the northwest and in southern Bolívar State. Moderate surpluses are forecast in a pocket of southern Venezuela. Deficits are expected in Guyana’s southeastern corner and in French Guiana.

On the Pacific Coast, a few pockets of surplus are forecast in Ecuador. Deficits are forecast for central Peru, moderate overall but exceptional in the Ucayali River’s middle reaches, and deficits are also expected in southern Peru. Surpluses are forecast in Loreto in the north, a pocket in the central Peruvian Andes, and spanning the border into Bolivia. Central and eastern Bolivia can expect deficits of varying intensity. Deficits of varying intensity are also forecast in nearly all of Chile with exceptional anomalies in pockets of the north and around the Gulf of Corcovado in the south. Near Santiago and Valparaiso deficits will be severe.

In Argentina, deficits are forecast in pockets of the Chaco in the north, in the eastern Pampas, along the border with Chile, and in Tierra del Fuego and the Falklands. Surpluses are forecast in northern San Luis Province. Moderate deficits are expected in southwestern Uruguay near the Rio de la Plata.

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

The forecast through June indicates that deficits of varying intensity will remain widespread in Brazil reaching from south of the Amazon through Mato Grosso do Sul and east to the Atlantic. Deficits will be exceptional in many pockets but will be especially widespread in Mato Grosso do Sul and São Paulo States. Notably, exceptional deficits are also forecast along the Paraguay River through its namesake and along the Paraná River through Brazil, Paraguay, and Argentina.

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Nations in the northern arc of the continent will see deficits shrink overall though exceptional anomalies will persist from Colombia’s northwestern coast through Medellin, trailing east to the Venezuelan border. Deficits will also persist with intensity in the nation’s southeast corner. Areas of moderate surplus include eastern Colombia into Venezuela, northeastern Venezuela into northern Guyana, and coastal French Guiana. Surpluses are forecast for Loreto in northern Peru and will increase in a pocket of the central Peruvian Andes. Deficits in the center of the country will shrink and downgrade. Bolivia will continue to experience deficits in the east and south though deficits in the extreme south will shrink. Surpluses spanning the Peru/Bolivia border will increase in Bolivia.

Moderate deficits are expected in northern Chile but deficits in the south around the Gulf of Corcovado, while shrinking, will remain intense. Deficits in northern Argentina will become mild while deficits in Buenos Aires Province increase. Surpluses will persist in a pocket on the province’s coast and will increase somewhat in the Andes of northwestern Argentina and in Mendoza and San Luis Provinces in the center of the country.

From July through September, deficits will remain widespread in Brazil, downgrading except in the most intense pockets which include regions of Mato Grosso do Sul and São Paulo. Deficits will retreat from the Paraná River but will be exceptional on the Paraguay River through Paraguay and will intensify in northern Buenos Aires Province. Other areas with a forecast of deficit include coastal Venezuela, French Guiana, the Cordillera Orientals through Colombia, coastal Ecuador, the Huánuco and Arequipa Departments of Peru, central Bolivia, and northern Chile. Surpluses will nearly disappear in the northern nations and will shrink or downgrade in Peru and Bolivia.

In the final quarter – October through December – some scattered pockets of deficit are expected along the Atlantic Coast from Venezuela through Brazil’s eastern tip. Deficits are also forecast for southern Colombia, central Bolivia, and from Peru’s southern tip to the Gulf of Corcovado in Chile. Surpluses are forecast from Cusco, Peru past Lake Titicaca to La Paz, Bolivia.

Please note that WSIM forecast skill declines with longer lead times.

IMPACTS
After nearly a decade of drought, Chile is taking steps to increase federal oversight of water issues by adding water resources to the role of its Public Works Ministry. Increasing dryness in the nation has been underscored as water shortages have now reached into the nation’s normally rainy south. The Los Lagos region, where reservoirs have heretofore been unnecessary, has for the first time ever received a formal declaration of water shortage from the federal government. Authorities state that 40 percent of the nation’s water scarcity issues are due to poor management, a problem the ministry intends to address through a digital, interactive basin-level platform.

La Niña has dumped triple the normal rainfall on Colombia’s coffee-growing region over the last few months, threatening to send Arabica prices up. Leaf-rust fungus, exacerbated by wet conditions, has already cost growers millions of dollars in lost crops. March precipitation was the highest ever recorded in the country and resulted in widespread flooding.

Conversely, drought in Brazil caused severe damage to the 2020 coffee crop in that nation and could affect this year’s production. A survey of coffee crop producers indicated that 77 percent of respondents anticipate drought-related problems with their 2021 harvest. Hot, dry weather could also suppress the safrinha (second) corn crop.

By the end of March, lack of rainfall in Brazil’s southern state of Paraná left the Pardo River at drought level. The Pardo flows into the Paraná River, which, as the second-longest river on the continent after the Amazon, winds 4,880 km (3,032 miles) through Brazil, Paraguay, and Argentina. Over the last 12 months, the level of the mighty Paraná has dropped 13 meters at Ciudad del Este, Paraguay, measuring just 5.12 meters at the end of March. In Puerto Iguazú, Argentina where the Paraná, Paraguay, and Iguazú Rivers meet, the water level of the Iguazú, the main source of water for the city’s residents, dropped 4 meters at the beginning of April, prompting citizen protests over water shortages.

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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