The Negro River, the Amazon's second-largest tributary, on Monday reached its lowest level since official measurements began near Manaus 121 years ago. The record confirms that this part of the world's largest rainforest is suffering its worst drought, just a little over two years after its most significant flooding.

In the morning, the water level in the city's port went as low as 13.5 meters, down from 30.02 meters registered in June 2021 – its highest level on record. The Negro River drains about 10 percent of the Amazon basin and is the world's sixth largest by water volume.

Madeira River, another main tributary of the Amazon, has also recorded historically low levels, causing the halt of the Santo Antonio hydroelectric dam, Brazil's fourth largest.

Throughout Brazil's Amazon, low river levels have left hundreds of riverine communities isolated and struggling to get access to drinkable water. The drought has also disrupted commercial navigation that supplies Manaus, a city of 2 million with a large industrial park.

Manaus is the largest city and capital of Amazonas, the state hit hardest by the drought. In late September, 55 of 62 municipalities there entered a state of emergency due to the severe drought.

"There is no more water to go through. Navigation is over," boatman Cledson Lopes Brasil said.

Brasil operates in Marina do Davi port, a getaway to dozens of riverine communities, some of them with sandy beaches that attract tourists. The once bustling area is now surrounded by parched soil, with many boathouses high and dry.

For a month now, Brasil has switched to a lower-powered boat, better suited for shallow waters. Still, he can't reach most communities along Taruma-Açu, a tributary of the Negro River. Some riverine dwellers must walk up to three hours to reach their houses, and tourism has stopped altogether.

Manaus and other nearby cities also suffer from high temperatures and heavy smoke from nearby man-caused fires for deforestation and pasture clearance. The drought is also the likely cause of dozens of river dolphin deaths in Tefe Lake, near the Amazon River. 

It is a startling contrast to July 2021, when Negro River waters took over part of the Manaus downtown area. The historic flood, which also ruined the crops of hundreds of riverine communities, lasted about three months.

The Negro River ends near Manaus, where it converges with the Amazon River, which is called the Solimoes River, in Brazil upstream from this confluence. In Brazilian maps, this marks the beginning of the Amazon, with the Negro River as the second main tributary. In international maps, the Amazon River begins in Peru.

Philip Fearnside, an American researcher at the Brazilian National Institute of Amazonian Research, a public agency, expects the situation to deteriorate, both during the ongoing event and in the future, with increasing frequency and severity of similar events with climate change.

He said surface water in the eastern equatorial Pacific Ocean is now warmer than during the "Godzilla" El Niño of 2015-2016 and is expanding. In the Amazon, these Pacific warmings primarily lead to droughts in the northern part of the region.

(Cover image via CFP)