South America: Water deficits in the Pampas will continue

23 October 2022

THE BIG PICTURE
The 12-month forecast through June 2023 indicates exceptional water deficits in Venezuela through the northern Orinoco River Watershed. Surpluses are forecast in the Orinoco Delta and coastal French Guiana.

Surpluses, primarily moderate, will be widespread in central Colombia though a few intense pockets are expected on the Caribbean Coast. Moderate surpluses are forecast near Quito, Ecuador.

In Brazil, deficits reaching exceptional intensity are expected in pockets of Amazonas, widespread in the west. Some moderate surpluses are forecast in Pará, but pockets of greater intensity are predicted in Brazil’s small eastern states and in central Bahia’s Chapada Diamontina region.

In Peru, a few pockets of deficit are predicted while Bolivia can expect severe deficits from La Paz through the Cordillera Real and exceptional deficits in the Eduardo Avaroa Andean Fauna National Reserve in the nation’s far southwest.

Widespread exceptional deficits are forecast in Chile from La Serena through Valparaiso and Santiago to the Gulf of Corcovado. In Argentina, deficits will be moderate in pockets of the northeast, severe through the Rolling Pampa region, and exceptional along several rivers in southern Patagonia and in Tierra del Fuego. Exceptional surpluses are forecast in coastal Chubut Province near the Valdes Peninsula and on the central coast of the San Jorge Gulf. Moderate deficits are forecast in Uruguay and the southeast corner of Rio Grande do Sul, Brazil.

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

The forecast through December indicates near-normal conditions for much of Brazil. However, exceptional deficits are forecast in Amapá; severe deficits on the Trombetas River in Pará; and deficits of varying intensity in Roraima and western Amazonas. Mixed conditions are forecast in coastal regions of Brazil’s far east, severe surpluses in a pocket of central Bahia and isolated moderate pockets in Minas Gerais, and moderate deficits in Rio Grande do Sul. Deficits in the northern Orinoco Watershed of Venezuela will shrink but remain intense in the west while surpluses continue in the Delta. Southern French Guiana can expect deficits. A few pockets of intense surplus are predicted near Colombia’s Caribbean Coast and moderate deficits in the south. Surpluses will linger near Quito, Ecuador, and deficits are expected along the north coast and in pockets of far northern and southern Peru.

Western Bolivia will see mixed conditions including exceptional deficits in the National Reserve in the southwest. In Chile, deficits will be moderate in Santiago but more intense in the nation’s southern half with anomalies reaching into Argentina. Deficits are predicted in the Argentine Pampas, exceptional in the Rolling Pampa region. Deficits are also expected in northeastern Argentina and Patagonia and exceptional anomalies in Tierra del Fuego. Surpluses will remain intense in a pocket of coastal Chubut and one on the central coast of the San Jorge Gulf. Southern Uruguay will see severe deficits, moderating through the north and into Rio Grande do Sul, Brazil.

From January through March 2023, deficits will continue to shrink but are expected in a few regions including northwestern Venezuela, Bolivia’s southwest corner, central Chile into Argentina, Tierra del Fuego, pockets in the eastern Pampas, Uruguay, and Rio Grande do Sul’s southeast corner. Moderate surpluses will emerge in Pará, Brazil, particularly in the north, and will emerge in the Serra de Curupira of southern Venezuela. Surpluses will shrink in the Orinoco Delta; persist in pockets of far northern Colombia, far eastern Brazil, and coastal Chubut, Argentina; and increase somewhat in Ecuador. Deficits in Uruguay and Rio Grande do Sul will moderate.

In the final quarter – April through June 2023 – surpluses are forecast in southern Pará, northern Guyana, near Quito, northwestern Argentina, and pockets in coastal Chubut and on the San Jorge Gulf. Deficits are predicted in northern Chile, Tierra del Fuego, and pocket on the central border of Paraguay and Argentina.

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

IMPACTS
Drought in Argentina’s grain belt has slowed planting and forced some farmers to abandon fields altogether. Soil moisture is at the lowest in 30 years in the corn producing regions and some wheat acreage has simply been abandoned. Cordoba, the state where a third of the nation’s corn is raised, has been the most affected. Experts are currently projecting that the nation’s 2022-2023 corn harvest will fall 4 percent behind that of the prior year, a figure whose significance will reverberate to the global market as Argentina is the world’s number 3 exporter of corn.

With persistent rainfall deficits threatening agricultural commodities, legislators in Uruguay requested a national drought emergency declaration. Dry conditions have resulted in poor volume and quality of crops like wheat, barley, and rapeseed, and negative consequences for livestock and dairy sectors. The emergency declaration was granted by the ministry of agriculture, releasing funds to affected areas.

Torrential rainfall in the Venezuelan state of Aragua triggered landslides that claimed 36 lives. Mud swept down the mountain in the town of Las Tejerías, stripping away many homes, and numerous streams overflowed in the town center, creating a landslide. Early October brought flooding to 10 other states as well. Around 20,000 rescue and recovery personnel have been deployed to the regions.

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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