South America: Intense water deficits in Brazil

22 July 2021

THE BIG PICTURE
The 12-month forecast through March 2022 indicates intense water deficits across northern Colombia and the northern Orinoco River Watershed in Venezuela. Elsewhere across the northern arc of the continent, pockets of surplus are expected in northern Ecuador and east of Cali in Colombia, southern Venezuela and the Orinoco Delta, the shared northern border of Guyana and Suriname, and at the intersection of the Negro and Branco Rivers in the northern Amazon Basin of Brazil.

ISciences_South_America_Composite_Adjusted_202104-202203_12mo_twitter.png

Widespread deficits ranging from severe to exceptional are expected in the Brazilian states of Mato Grosso, Mato Grosso do Sul, São Paulo, and Paraná. Deficits reaching exceptional intensity are forecast for parts of western Amazonas and Acre, Pará and Amapá, and Maranhão. Pockets of deficit are also expected in the southern states.

Much of central Peru will be dominated by deficits, more intense in the east. Surpluses are forecast for a pocket in the central Peruvian Andes and from Cusco in the southeast into Bolivia. West-central and eastern Bolivia can expect deficits. Generally moderate deficits are expected in eastern Paraguay.

In Argentina, moderate deficits are forecast in the northeast leading south where anomalies will intensify north of the Salado River in Buenos Aires Province. Intense deficits are forecast in the south and in Tierra del Fuego and the Falklands. Northern La Pampa Province can expect moderate surpluses. Deficits are forecast for nearly all of Chile, exceptional from central Chile past the Gulf of Corcovado reaching into Argentina.

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

The forecast through September indicates widespread deficits in Brazil south of the Amazon. While existing pockets of surplus north of the river will downgrade, moderate surpluses will emerge in northwestern Pará. Deficits will be exceptional in many areas including the Purus River Watershed in the west, and Pará, Mato Grosso do Sul, and São Paulo States. Deficits from northern Colombia through northwestern Venezuela will shrink but remain widespread with exceptional anomalies near the metropolitan areas of Caracas and Merida, Venezuela. Severe to extreme surpluses will persist from Quito, Ecuador across the border into Colombia while surpluses of generally lesser intensity are forecast in the Orinoco Delta, southern Venezuela, and northern Guyana into Suriname.

ISciences_South_America_Composite_Adjusted_202104-202203_3mo_twitter.png

Severe deficits will dominate central Peru and deficits in the south near Arequipa will intensify, becoming exceptional. Surpluses will remain intense in the south from Huancayo past Cusco but anomalies spanning the border with Bolivia, while remaining widespread, will downgrade. Deficits are expected in many other regions of Bolivia, eastern Paraguay, and Alto Paraguay Department in the northeast. Notably, exceptional deficits are forecast along the Paraguay River through its namesake.

In Argentina, deficits will be extreme along the Paraná River, and severe to extreme between the Paraná and Salado Rivers in Buenos Aires Province. Moderate deficits are expected in southern Buenos Aires Province, and deficits of varying intensity are forecast for northeastern and southern Argentina, intense in Tierra del Fuego and the Falklands. Surpluses will persist in La Pampa Province, San Luis and Cordoba Provinces, and pockets in the Andes in the nation’s northwest. Deficits of varying intensity are expected throughout much of Chile, moderate in Santiago but exceptional in Biobío Province.

From October through December, intense deficits will persist in west-central Pará, Brazil, at the confluence of the Tapajós and Amazon Rivers; border regions that Chile shares with Bolivia and northern Argentina; the Upper Chico River region of southern Argentina; and Tierra del Fuego and the Falklands. Deficits of lesser intensity are forecast throughout much of Chile reaching into southern Argentina. Other areas of deficit include Caracas, Venezuela; Amapá and Maranhão, Brazil; south-central Colombia; Peru’s southern corner; south-central Bolivia; and Corrientes, Buenos Aires, Río Negro, and Chubut Provinces in Argentina. Some pockets of surplus will emerge in Brazil from Pará into Tocantins, and will persist in the Orinoco Delta; near Cali, Colombia; north of Quito, Ecuador; and north of Lake Titicaca in Peru.

The final quarter – January through March 2022 – indicates deficits from Chile into border regions of neighboring countries, and mild to moderate deficits in a path from Caracas into Peru’s northwestern tip. Mild to moderate surpluses will increase in the northeastern Amazon Basin and surpluses will emerge in a pocket of central Bolivia.

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

IMPACTS
In an effort to keep Brazil’s power grid operating and avoid rationing in the midst of a drought, the director of the national grid has asked power producers to postpone maintenance that would take any plant offline. The directive will stand for several months, at least until the rainy season in November when water levels will hopefully be restored in reservoirs that feed hydroelectric plants. While reservoirs are currently below average in all regions of the country, the Southeast and Midwest are the lowest, expected to close July at just a quarter of capacity.

Dry conditions could exacerbate a fire season already complicated by illegal logging and consequent burning to clear the land. Brazil is currently under a national 120-day ban on unauthorized outdoor fires, an effort to curb annual burning and deforestation in the Amazon, and the military has been deployed in support. Past experience, however, has not proved these tactics to be effective. This year’s June fire total in the Amazon was the highest in 14 years.

A recent study indicates that the Amazon rainforest, long celebrated as a carbon sink, has become a carbon source in parts of its eastern basin. Experts cite warming trends and deforestation as primary factors in the transition. Cutting trees to create cropland reduces CO2 absorption, and subsequent burning to clear the land increases production of CO2, a greenhouse gas.

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.

Subscribe to our monthly Water Watch List

Search blog categories

Search blog tags