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Amazon drought cuts river traffic, leaves communities without water and supplies

The mass die-off of Amazon dolphins is under investigation, with researchers suspecting high water temperatures may be the cause. Image courtesy of Miguel Monteiro/Mamirauá Institute.

  • Falling water levels in the rivers and lakes of the Brazilian Amazon are restricting the flow of ships and boats, the main form of transport in the region and the only means of access to health and education facilities for many communities.
  • This year’s drought is exacerbated by two simultaneous natural events, the main one being El Niño, that inhibit the formation of rain clouds, further reducing the already low rainfall recorded during the dry season.
  • More than 100 Amazonian river dolphins were found dead in a lake in Amazonas state, likely due to high water temperatures and low water levels, according to researchers.
  • The state of Amazonas is preparing for the worst drought in its history, which will affect 500,000 people by the end of October; the federal government has created a task force to mitigate the impacts, promising to send water, food and medicine.

A severe drought has thrown the Brazilian Amazon into an emergency, with water levels in rivers and lakes across the basin falling to unprecedented lows in September. This has restricted the movement of people and goods by boat, making it even more difficult for remote communities to access health and education facilities, and left thousands of people facing water and food shortages.

In addition to the humanitarian crisis, the severe drought is also being blamed for the massive die-off of fish and river dolphins. There are also concerns about forest fires. This scenario could worsen dramatically by the end of October, when the drought is expected to be at its most severe.

The Amazon typically receives less rainfall during this current time of year. But the 2023 dry spell has been exacerbated by two simultaneous natural events that inhibit cloud formation, further reducing the already low rainfall in the region.

One of these phenomena is El Niño, the abnormal warming of the surface waters of the equatorial Pacific Ocean, which produces east-to-west air currents over the Amazon Rainforest. Another factor is the warming of the waters of the northern tropical Atlantic Ocean, which creates north-to-south winds across the biome. These air currents are an obstacle to the formation of rain clouds.

“With the two phenomena acting simultaneously, we have a more intense drought that also affects a larger area of the Amazon biome,” Renato Cruz Senna, a meteorologist and researcher at the National Institute for Amazonian Research (INPA) in Brazil, told Mongabay by phone.

The critical level of the Amazon’s rivers is a major problem. River navigation is the primary transportation method across the world’s biggest rainforest, and the only means of access for many communities, especially in the western part of the biome, with few road connections.

Coari is one of the Amazonian municipalities currently suffering from shortages of food and other essential products. Image courtesy of Amazonas Civil Defense.

The flow of boats on the great rivers — the Amazon, Solimões, Negro, Branco, Madeira, Purus and Juruá — supplies the entire region with essential goods sent from other parts of Brazil, from food items like beans and beef to materials like cement and iron. The same routes are used to transport commodities, from televisions and bicycles produced in the Manaus Free Trade Zone, to grain for export.

Authorities say 90% of regular vessels are now operating with some kind of restriction in the state of Amazonas, which has ordered cargo capacity to be halved.

The municipality of Benjamin Constant, 1,120 kilometers (700 miles) from the Amazonas state capital Manaus, has been left isolated by the drought. It sits at the confluence of the Solimões and the Javari, the river that forms the border between Brazil and Peru. Water levels here have receded so much that huge sandbanks have emerged in the middle of the rivers, making navigation unfeasible, even to the neighboring municipality of Tabatinga.

“The situation is delicate, with the risk of total shortages if the river continues to recede,” David Bemerguy, the mayor of Benjamin Constant, told Mongabay by WhatsApp. “It’s the worst drought ever seen here because the river has more sandbanks, with less navigability.”

In addition to the shortage of drinking water, gas, food and other essential supplies, the municipality of 37,000 inhabitants faces a growing public health problem. “We have worsening respiratory diseases, diarrhea, and other health problems associated with the drought. We depend on a river connection to help patients. The current situation is unthinkable,” Bemerguy said.

On Sept. 26, the Brazilian federal government released $41 million reais ($8,2 million) to dredge 8 km (5 mi) of the Solimões and reestablish the link between Benjamin Constant and Tabatinga.

The municipality of Benjamin Constant in Amazonas state is isolated by the low water level of the river that connects it to the neighboring municipality of Tabatinga. Image courtesy of Amazonas Civil Defense.

Drought will affect 500,000 people

Benjamin Constant is just one of 60 municipalities across Amazonas, out of the total of 62 in the state, that are currently suffering from the effects of the drought. Manaus, the state capital, has also been affected.

In the Juruá River Basin, remote communities have also been isolated due to the drop in the river level. News outlet Amazônia Real reported that these communities are experiencing supply shortages.

Amazonas authorities are bracing for what they expect to be the worst drought in the state’s history, which will affect the distribution of water and food to 500,000 people by the end of October. Some 20,000 children may lose access to schools.

The dry season began earlier than expected in the Brazilian Amazon. By August, the level of the Solimões River had already dropped considerably in the municipality of São Paulo de Olivença, Amazonas state. Image courtesy of Amazonas Civil Defense.

The drought is also affecting other Amazonian states in Brazil. In Rio Branco, the capital of Acre state, the main concern is the freshwater shortage due to the low level of the Acre River. At least 17,000 people have already been hit by the shortage. The drought is also severely affecting rural producers and extractive communities.

In Porto Velho, the capital of Rondônia state, the Madeira River hit its lowest level in September. With their wells running dry, people living along the river are traveling up to 30 km (19 mi) to buy freshwater, according to news outlet G1. At least 15,000 people are suffering from water shortages on the banks of the Madeira.

The Brazilian federal government has created a task force to mitigate the impacts of the drought in the region, promising to send water, food and medicine. The effort also includes dredging rivers, fighting forest fires, allocating funding, and facilitating access to social service programs. “We have a very worrying situation. It’s a very long drought,” Brazil’s minister of environment and climate change, Marina Silva, told the Folha de S.Paulo newspaper.

More than 100 Amazonian dolphins, including endangered pink river dolphins, were found dead in Lake Tefé, Amazonas state. Image courtesy of André Zumak/Mamirauá Institute.

The river dolphin tragedy

Amid the severe drought, more than 100 Amazonian dolphins, including endangered species like the pink river dolphin (Inia geoffrensis) and the tucuxi (Sotalia fluviatilis), were found dead in Lake Tefé, fed by the Solimões in Amazonas state.

“I’ve never seen anything like this,” Miriam Marmontel, an Amazonian aquatic mammal researcher at the Mamirauá Institute, said in a video message to Mongabay. “It’s a huge die-off of dolphins in a localized area due to high temperatures. We’re worried because these are two endangered species, charismatic animals that are symbols of the Brazilian Amazon.”

The cause of the dolphin deaths hasn’t yet been confirmed, but researchers say the suspect the water’s high temperature and the lake’s low level may have been factors. Experts are also looking at the possibility of toxins or pathogens in the water. The environment ministry’s Chico Mendes Institute for Biodiversity Conservation (ICMBio) will investigate the die-off.

Many other lakes and rivers in the Brazilian Amazon have already recorded large numbers of dead fish due to the drought.

Many lakes and rivers in the Brazilian Amazon, like Manacapuru in Amazonas state, recorded mass fish die-offs due to drought. Image courtesy of Amazonas Civil Defense.

The dry season in the Brazilian Amazon began earlier than expected and has been more severe than in previous years. Weather forecasts indicate the drought conditions will likely last longer in 2023, delaying the rainy season.

“We will have low-intensity rains from October onward due to El Niño,” Sidney Abreu, from the Brazilian National Institute of Meteorology (INMET), told Mongabay by phone. “This rainfall deficit should last until the second half of December, perhaps even into next year.”

With less rainfall, river levels in the Amazon will likely take longer to return to normal, prolonging navigation problems in the region. Mongabay received a forecast of flows for the next three months from Ana Paula Cunha, a drought researcher at the National Center for Monitoring and Early Warning of Natural Disasters (CEMADEN). The data show flows well below average throughout the region.

Huge sandbanks in the bed of the Solimões River hamper the supply of essential products in the municipality of Coari, Amazonas state. Image courtesy of Coari City Hall.

New restrictions on navigation are expected in the coming weeks, according to Luís Fernando Resano, president of the Brazilian Association of Cabotage Shipowners (ABAC), which represents companies that transport cargo along the rivers in the Amazon Basin. “With depth restrictions to avoid hitting sandbars, ships are carrying less cargo than they could. That makes freight more expensive,” he told Mongabay by phone.

“Everything suggests that we will have to reduce cargo even more as the rivers recede, which means fewer products with higher prices in the region. The greatest impact will be felt in the supermarket,” he said.

According to Senna, the INPA researcher, river levels in the Amazon may reach record-low levels in late October. “The level of the Rio Negro is dropping by 1 meter [3 feet] every three days, something that has never been recorded before,” he told Mongabay.

He said communities living in the Amazonian region have become used to intensive flooding, but aren’t as resilient to the effects of severe droughts. “It’s a very chaotic process for the region. When rivers and lakes can’t be navigated, the population suffers all kinds of restrictions. The drought that is predicted for the region in 2023 is unprecedented.”


Banner image: The mass die-off of Amazon dolphins is under investigation, with researchers suspecting high water temperatures may be the cause. Image courtesy of Miguel Monteiro/Mamirauá Institute.

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