South America: Widespread water deficits to persist in Brazil & Chile

21 December 2020

THE BIG PICTURE
The 12-month forecast through August 2021 indicates intense water deficits in a vast region of central Brazil from Rondônia in the west into Bahia in the east and from Pará in the north through Paraná in the south. Deficits will be exceptional in many areas. Surpluses, primarily moderate, are forecast in the northeastern Amazon Basin along with transitional conditions (pink/purple).

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Coastal regions of Guyana and French Guiana can expect moderate surpluses, though southeastern French Guiana will experience deficits. Surpluses in the Orinoco Delta of Venezuela will be extreme, but exceptional deficits will form a wide band north of the Apure and Orinoco Rivers and will reach well into Colombia north of Bogota, though downgrading slightly. Severe deficits are expected in eastern Ecuador.

In Peru, surpluses are forecast for the northern portion of the Marañón River Watershed and mixed conditions in its southern extent. Deficits are forecast from Cusco Department in southern Peru past Lake Titicaca and through La Paz, Bolivia, skirting surpluses near Santa Cruz, then turning south through Sucre. Bolivian regions near Brazil can also expect deficits.

Intense deficits are forecast for many regions of Chile including exceptional anomalies in Valparaiso, Santiago, and along much of the Bío-Bío River. In Paraguay, moderate to severe deficits are forecast in the east, severe along the Paraná River into Argentina. Argentina can expect intense deficits in the northeast along with a few isolated surpluses, moderate deficits in Córdoba Province in the northern Pampas, and intense deficits in western Patagonia near the Chilean border. Deficits in the Falkland Islands will reach exceptional intensity.

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

The forecast through February 2021 indicates that deficits will shrink considerably overall but will remain widespread in Brazil, and a vast band of surplus will emerge across the northern portion of the continent. Surpluses of varying intensity are forecast through the northern Amazon Basin from northern Peru through southern Colombia and Venezuela, Brazilian regions north of the Amazon, as well as western Suriname, northern Guyana, and the Orinoco Delta. Surpluses will be exceptional along portions of the Amazon from Manaus until it reaches the Putumayo River, and along the Japurá River.

ISciences_South_America_Composite_Adjusted_202009-202108_3mo_twitter.png

Intense deficits will persist from northwestern Venezuela to Bogota, Colombia. Widespread deficits of varying intensity are forecast for much of Brazil south of the Amazon. Regions with a forecast of exceptional deficit include western Amazonas and Acre, western Bahia including the São Francisco River, and the Tocantins and the Lower Xingu Rivers in Pará. In Bolivia, intense deficits are expected from Lake Titicaca through La Paz and south past Sucre, and severe deficits in the far east. Paraguay can expect deficits in the east and severe to extreme deficits along its namesake river through the center of the nation. Severe deficits will trace the path of the Paraná River through Argentina. Pockets of surplus and deficits are forecast in northwestern Argentina, and surpluses in a pocket of the Chaco Austral in the north. Intense deficits will persist in southern Chile, reaching across the border into Argentina. Deficits in Uruguay will shrink and moderate.

From March through May 2021, normal water conditions will return to many regions of the continent and surpluses will increase in a broad band from Peru through the northern Amazon Basin to the Atlantic Coast. Surpluses will be widespread but moderate overall. Much of the remainder of the continent will return to normal water conditions but deficits will persist in north-central Venezuela; western Bahia, Brazil; central Bolivia and its southern tip; along the border of Chile and Argentina; and from Santiago, Chile, to the Gulf of Corcovado.

In the final quarter – June through August 2021 – surpluses in the north will shrink considerably, persisting primarily in Peru. Deficits are forecast in Bahia, Brazil; near La Paz, Bolivia; and northern Chile and nearby regions of neighboring Bolivia and Argentina, where pockets of surplus are also forecast.

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

IMPACTS
Though much of South America is experiencing drought conditions, heavy rainfall in mid-December led to flooding and a landslide in Santa Catarina State in southern Brazil that claimed 12 lives and damaged houses, roads, and bridges.

Drought in Brazil has left reservoirs in the nation at historically low levels, threatening hydroelectric production. President Bolsonaro appealed to citizens to reduce personal energy consumption. Heavily reliant on hydroelectric power, Brazil has had to increase thermoelectric production during the drought, a much more expensive process.

Forecasters have once again slashed estimates for Brazil’s corn crop based on drought impact in the south, particularly in Rio Grande do Sul. Recent rainfall simply wasn’t enough to offset prior shortfalls during the planting season, resulting in estimates mimicking last year’s drought-ravaged output. Yields are expected to be the lowest since the 2014/2015 season.

Argentina’s national government has declared a drought emergency in the northern province of Santiago, which joins several other provinces - Córdoba, Formosa, Chaco, and Corrientes - already designated. The declaration opens up subsidies for agricultural producers in the regions, including alfalfa, cotton, corn, meat, and milk farmers.

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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