Rivers approach historic drought in parts of the Amazon – 10/03/2023 – Environment

Data compiled by the Civil Defense of Amazonas show a worsening of the drought and the situation approaching extreme times of drought — at the worst water levels in historical measurements — in rivers that are the heart of this portion of the Amazon.

The realities are diverse, just as there are different Amazons, but the data gathered by Civil Defense and analyzes carried out by research and monitoring institutes point to a drought close to the extremes in the upper and middle Solimões river, in the lower Negro river (where Manaus is located) and on the Madeira River.

In these regions, the most visible consequences of the drought have occurred so far. Communities were isolated in Tabatinga (AM) and Benjamin Constant (AM), in upper Solimões. In the lake where Tefé (AM) is located, in the middle Solimões, more than 120 dolphins and tucuxis died in ten days.

In Manaus, the banks of the Negro River are closed. Along the Madeira River, the Santo Antônio hydroelectric plant – the fourth largest in the country – suspended operations.

The tendency is for the ebb of the rivers to continue and advance through November, according to researchers interviewed by Sheet –in other Octobers, the end of the drought usually occurs in the second half of the month.

There will be less rain, just as there was less rain in months that traditionally have low rainfall – July, August and September. This will mean a slower recovery in river volumes, with impacts that could last until the next drought, in 2024.

Civil Defense data, which uses measurements from ANA (National Water and Basic Sanitation Agency), show an elevation of the Solimões River in Tabatinga (AM) of 0.11 m on Monday (2). The worst indicator in the border city occurred on October 11, 2010, with –0.86 m. The negative value is due to a methodological issue, due to a reference initially adopted.

Fonte Boa (AM), a city close to Tefé, in the middle Solimões, had an elevation of 10.53 m, compared to a minimum of 8.02 m on October 16, 2010, according to data compiled by Civil Defense.

In Manaus, according to an analysis carried out by Inpa (National Institute for Amazonian Research), the elevation of the Negro River, at 15.4 m, is the 13th worst in a 120-year history of measurements. At the end of October 2010, the worst level was recorded: 13.63 m.

In Nova Olinda do Norte (AM) and Humaitá (AM), the levels of the Madeira River are close to historic lows, recorded in 1995 and 1969, respectively. The hydroelectric plant that had to interrupt power generation due to the river’s drought is in Rondônia.

Of the 62 municipalities in Amazonas, 24 are in an emergency situation, according to a bulletin updated by Civil Defense this Tuesday (3). This is the case for all 7 cities in upper Solimões and 7 of the 8 cities in middle Solimões.

The government of Amazonas and the City of Manaus also declared an emergency situation, a way of facilitating administrative actions in the region.

“The drought usually lasts until mid-October. Now, the forecast is that it will last until the beginning of November, with the rivers ‘going down'”, says Renato Senna, climatologist and researcher at Inpa. “What happens must be among the worst droughts in history.”

The drought, however, will not be “absolute”, according to the researcher. Rain showers will occur, but later, in smaller quantities and more isolated.

“In any case, there is a generalized drought in these Amazon basins, such as the Negro, Solimões, Branco and Jutaí rivers”, says Senna. “The situation is likely to get worse.”

The severe drought is the result of a combination of two phenomena: El Niño, which is an above-average warming in the Pacific Ocean, close to the Equator, and the warming of the North Tropical Atlantic.

The anomalies that El Niño causes in the Amazon, with less rain, will still continue in the region, according to meteorologist Giovanni Dolif, from Cemaden (National Center for Natural Disaster Monitoring and Alerts).

“The center and south of the Amazon experience seasonal dry periods. You have to wait for what is average and what is outside the average”, says Dolif. “We haven’t yet had all the anomalies that El Niño can cause.”

There has already been below-average rainfall in periods that are already little rainy. Now, this should be repeated during the rainy season in the Amazon.

“The beginning of the rains will have smaller volumes. The recovery of river levels will be delayed. The minimums in October and November could reach historic lows”, says the meteorologist.

According to him, it is possible that the rivers will not recover to the expected average values, which could reflect the next dry period. “There is already a concern for next year’s drought,” says Dolif.

He sees the current drought scenario as being of “considerable magnitude”, but states that it is not possible to predict whether extreme situations will be repeated in a widespread manner in the Amazon.

The Madeira River basin is one of the most affected by the drought, according to researchers. According to experts, what is happening on the Jutaí River, in western Amazonas, also deserves more attention, as it is experiencing a drought not seen in 15 years.