South America: Widespread water deficits will persist in Brazil

22 February 2021

THE BIG PICTURE
The 12-month forecast through October 2021 indicates intense water deficits in much of Brazil south of the Amazon River from Rondônia in the west through Bahia in the east and from Pará in the north into Paraná in the south. Deficits will be exceptional along many rivers.

Surpluses, primarily moderate, are forecast north of the Amazon reaching into Venezuela’s southern tip. Surpluses are also expected in northeastern Venezuela, Guyana, Suriname, and coastal French Guiana, though Guiana’s eastern border will see exceptional deficits.

ISciences_South_America_Composite_Adjusted_202011-202110_12mo_twitter.png

Elsewhere across the northern arc of the continent, exceptional deficits are forecast in northwestern Venezuela in the watershed of the Orinoco’s western tributaries and will reach through Colombia in a band north of Bogota to the Pacific. Exceptional deficits are also expected in southeastern Colombia leading into Brazil. A pocket of surplus is forecast near Cali, Colombia. Severe deficits are expected in eastern Ecuador. Moderate to severe deficits are forecast for central Peru reaching exceptional intensity near the Brazilian border, but moderate surpluses are expected near Cusco.

Bolivia, too, will experience deficits in pockets throughout the country. Exceptional deficits will trace the path of the Paraguay and Paraná Rivers through Paraguay and Argentina, and moderate to severe deficits are forecast for southern Uruguay. Though normal water conditions are expected in much of Argentina, deficits are forecast along its border with Chile, along several rivers, and in the eastern Pampas, Tierra del Fuego, and the Falklands. Surpluses are forecast in a pocket of San Luis Province. In Chile, deficits will be intense in central and southern regions and will include extreme conditions around Santiago, while generally milder anomalies are expected in the north.

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

The forecast through April 2021 indicates that deficits will shrink considerably overall but will remain widespread in Brazil and southern Chile, and surpluses will emerge in a wide belt across the northern portion of the continent. Surpluses of varying intensity are forecast in the northern Amazon region reaching into eastern Colombia and southern Venezuela and through Guyana, Suriname, and French Guiana, though intense deficits will persist in eastern French Guiana. Surpluses are also forecast to emerge in southwestern Colombia, encompassing Cali, and along the Orinoco River’s path in central Venezuela. Surpluses will persist in the Orinoco Delta. Anomalies will be intense in eastern Colombia and spanning the northeast border of Amazonas, Brazil into Pará. Moderate surpluses will emerge in northeastern Peru, but intense deficits will persist along the central border with Brazil.

ISciences_South_America_Composite_Adjusted_202011-202110_3mo_twitter.png

Widespread deficits of varying intensity are forecast for much of Brazil south of the Amazon through São Paulo State. Deficits will be exceptional in many large pockets but particularly in western Bahia and eastern Mato Grosso do Sul. Moderate surpluses will emerge in eastern Paraguay and pockets in Brazil’s southern states. Deficits on the Paraná River will be exceptional along Paraguay’s eastern border but will downgrade to severe through Argentina. Transitional conditions are expected on the Paraguay River. Surpluses will emerge in San Luis Province, Argentina and deficits in the Pampas will shrink. In Chile, scattered pockets of moderate deficit are forecast in the bulk of the country north of Santiago, but deficits will be intense in the south, spilling across the border into Argentina.

From May through July 2021, normal water conditions will return to many regions of the continent as both deficits and surpluses shrink. Widespread deficits will persist in central Brazil, however, including pockets of exceptional deficit. Pockets of moderate surplus will persist from the Orinoco Delta through the northern Guianas region, and will linger in other isolated pockets in the north. Scattered, small pockets of moderate deficit are forecast in Ecuador, Peru, and Bolivia. Intense deficits will re-emerge on the Paraguay River through its namesake. Deficits on the Paraná River will remain intense in Brazil but will downgrade in Paraguay and nearly disappear through Argentina. Moderate deficits will increase somewhat in the eastern Pampas and in southwestern Uruguay. Surpluses in San Luis Province, Argentina will shrink slightly. Intense deficits in southern Chile will shrink and downgrade considerably, and surpluses will emerge in the Patagonia Icefields.

In the final quarter – August through October 2021 – surpluses in the north will nearly disappear and conditions elsewhere will remain much the same as forecast through July. Deficits will intensify near Caracas, Venezuela.

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

IMPACTS
Rainfall throughout February has created deadly flood conditions in several regions of South America. In Ecuador, the middle of the month brought torrential rains that triggered flooding and landslides in Chimborazo and El Oro Provinces killing one person and injuring others. Two bridges were damaged as well as many roads, houses, public buildings, crops, and livestock.

Several rivers overflowed in Peru’s Huánuco Region causing flash flooding on 10 February in Marañón Province. One fatality was reported and damages to over 400 homes, as well as to bridges, roads, and cropland. Heavy rainfall triggered landslides days earlier in Ichuña district destroying four homes and damaging 14 other buildings. In late January, at least six rivers burst their banks in Lampa Province, compromising infrastructure and triggering a state of emergency. In southern Peru, flooding and mudslides killed one person in Cusco.

Glacial retreat in the Peruvian Andes, exacerbated by greenhouse gas emissions generated from human activities, will likely raise the threat of flood to 120,000 residents.

In Brazil’s northwestern state of Acre, over 100,000 people have been affected by flooding after the Juruá, Iaco, Tarauacá, Envira, Purus, and Acre Rivers breached their banks. Two people died from mudslides triggered by flooding in the state of Minas Gerais, and 138.6 mm (5.5 inches) of rainfall in 24 hours pummeled the city of Diamantina. In Pará State an emergency was declared in the municipality of Ipixuna do Pará after heavy rain flooded the city.

Disaster struck Paraguay, too, as floods and landslides claim 10 lives early in the month.

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