CPRM points out that the Rio Negro floods are expected to reach 29.40 meters in Manaus

Bruno Pacheco – Cenarium Magazine

MANAUS – The Geological Service of Brazil (SGB – CPRM) released on Wednesday, 31, the first flood alert of the Negro River in Manaus in 2022. According to the agency, the estimate is that the water level should reach 29.40 meters this year, considering 80% confidence. The current level of the Rio Negro in the ruler that measures the daily behavior of the waters is 27.16 meters.

Last year, on June 16, the level of the Rio Negro reached the highest level in its history, in 118 years of measurement, when it reached 30.02 meters. The probability that the mark will be surpassed in 2022 is low, says the geosciences researcher at SGB – CPRM, Luna Gripp Simões Alves.

“We do expect that this year there is a high probability of an extreme event happening, in this recurrence of 15%, but at the same time the possibility of exceeding the river level, which we saw last year, is very low,” said the researcher.

In terms of reference, Gripp continues, the probability that the Rio Negro will reach the flood quota of 27.50 meters is 99% in 2022. The chance that the severe flood quota of 29.00 meters will be exceeded is 78%; on the other hand, the forecast that the maximum historical quota of 30.02 meters will be reached is only 12%.

The data released by CPRM are based on the information from the National Hydrometeorological Network, a responsibility of the National Water and Basic Sanitation Agency (Ana), which aims to assess the availability of water and to know the hydrological regime of the eight Brazilian river basins and their constituent sub-basins. Besides the forecast for Manaus, this year the CPRM released an alert for the cities of Itacoatiara and Manacapuru.

Manacapuru

In Manacapuru, a city in the Metropolitan Region of Manaus (RMM), the quota of the Solimões River on Wednesday, 31, is 17.52 meters. The CPRM forecast is that the water level that bathes the city will reach 19.90 meters in 2022, considering 80% confidence. The probability that the river’s flood quota of 18.20 will be exceeded is 99% this year.

According to CPRM, the probability that the severe flood quota of 19.60 meters will be reached is 70%. The chance that the historical maximum of 20.86 meters will be exceeded in 2022 is only 4%, according to the agency.

Itacoatiara

In Itacoatiara, 270 kilometers from Manaus, the level of the Amazon River, whose basin is considered the largest in the world, is 13.23 meters this Wednesday, 31, according to researcher Luna Gripp. The forecast is that the water level will reach 14.70 meters in 2022, considering 80% confidence.

According to the CPRM, the probability that the flood level of 14.00 meters will be exceeded in 2022 is 98%, while the chance that the severe flood quota of 14.20 meters will be exceeded this year is 94%. The possibility that the historical maximum of 15.20, recorded in 2021, will be reached, on the other hand, is only 8%.

Above expectations

According to the meteorologist Ricardo Dallarosa, from the Amazon Protection System (Sipam), the agency’s forecast for the next quarter of the year is rain above the expected in the Western Amazon. One of the factors that explains the above average level of rainfall is due to the La Niña phenomenon which, as opposed to El Niño, is characterized by the abnormal warming of the surface waters of the Central and Eastern Tropical Pacific Ocean.

According to Dallarosa, the warmer the sea, the more water vapor is created and this causes even more rainfall. The Amazon, however, begins to feel the consequences of the La Ninã phenomenon only about three months after it begins, and the condition is altered along the way to the region.

“We need to observe that it is an alteration that takes a certain time delay until it starts in the Amazon region, because it doesn’t come directly as the humidity from the Ocean comes. It changes a condition of atmospheric circulation three or two kilometers away, which is the case in the Amazon, and then begins to influence the zones here about two to three months after it is installed there,” explained Ricardo Dallarosa.

Also according to the meteorologist, the CPRM does not expect the end of La Niña in the near future, because of the consistency of rainfall levels in this first quarter of the year and the return of normal conditions for runoff not happening immediately in the Amazon. Dallarosa says that the phenomenon is forecast to remain for the next three months.

“In the same way that it takes a while for the condition to manifest itself in the Amazon, there is a small delay [English word for delay] to normalize the equal condition as well,” reinforced Dallarosa.

The next CPRM alerts are scheduled for April 29 and May 31 this year. The events are to be broadcasted on the entity’s YouTube channel, available at the link.

Watch this Wednesday’s flood alert: