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Brazil dams: 1 million live close to danger

Brazil dams: 1 million live close to danger

Data visualization Brazilian dam safety population near dams EN

According to DW analysis, Brazil is home to approximately 1 million people. The situation raises alarm bells about the possible consequences of yet another accident in the country, which has seen three large-scale dam disasters since 2009. 

The finding includes all those living in populated areas no more than a kilometer away from one of the 1220 dams that combine “high risk” and “high potential damage” classifications in Brazil’s National Dam Safety Information System (SNISB). 

A dam with a high-risk classification is one that has severe structural damage, design flaws, and is not maintained properly. This puts it at greater risk of safety incidents and organizational mishaps that could lead to a break. A high potential for damage classification means that such a failure could have serious economic, human, and environmental consequences. 


Data visualization Brazilian dam safety population near dams EN


This problem is being exacerbated because of poor governance. Many dams lack safety and emergency plans, despite legal requirements. 

According to SNISB data, 39 dams that were deemed “high risk” or “high potential damage” contain mining waste. This is particularly unstable, according to SNISB data from February 2022. The recent disasters in the cities of Mariana in 2015 and Brumadinho in 2019 involved such dams. 

However, most of the most dangerous structures are water storage and irrigation Dams. They’re mostly located in the Northeast region, which has historically been prone to water shortages.  

Many of the reservoirs in the area were built to offset drought. They pose a risk to 600,000. 

Dams  a sign of infrastructure neglect

Riacho da Cruz is a semi-arid town with around 3,000 inhabitants. Rain is scarce and rivers often run low there.  

Nearly everyone lives in this area, which is just downstream from a dangerous dam. Built in 1957 to help keep water flowing during frequent droughts, the dam is a good example of the kind of structures found scattered across most of Brazil’s Northeast.

Data visualization Brazilian dam safety satellite image EN

Mariano Andrade da Silva is a researcher on health and disasters at Fiocruz, a leading Brazilian academic institution. He says, “In the 1960s & 70s, government tried to promote water safety in this region.” These efforts included the construction of water reservoirs in areas that are often in drought.  

“Without proper maintenance, those structures have turned into a risk for the population,” adds da Silva. 

In addition to neglected state infrastructure, da Silva describes “orphan” dams. These dams are either not being maintained or the person responsible is unknown.   

As a result, 10 people for every 1,000 in the Northeast live close to a dangerous dam. This is the highest number in Brazil’s regions. About three out of every 1000 people in the Southeast, where wealthier states like Rio de Janeiro or Sao Paulo are located, live in a similar circumstance. 

The situation is made worse by a lack of resources

The problem is made worse by a lack of resources in areas where these dams are situated. A recent survey conducted by the Brazilian Institute for Geography and Statistics, IBGE, found that twenty percent (22%) of northeastern cities have at least one dam.

Civil defense services are responsible for implementing risk mitigation programs. This includes identifying vulnerable areas and creating contingency plans. They also coordinate rescue efforts in the event of disaster.  

“A disaster can happen in an unlikely situation. However, a disaster can cause not only death but also the destruction and devastation of entire communities.” Da Silva says, adding that reservoirs provide water for both human consumption as well as agriculture. He explains that a dam failure can also pose a threat to local food security and water security. 

The consequences of such events can be seen in recent history. Cocal, a city that had 25,000 residents in the northeastern Piaui, experienced an anti-drought flood in 2009. The event resulted in the deaths of nine people, displacement of hundreds, and a serious threat to the local agricultural economy. 

Picture shows a man paying tribute to victims who died in the 2019 dam disaster in Brumadinho city, Minas Gerais state, Brazil.

One year after the disaster, a man gives tribute to the victims at the Brumadinho dam accident in January 2020

Brazil has seen numerous major dam disasters since then. The 2015 Mariana disaster and the 2019 Brumadinho catastrophe were two of the country’s most severe dam accidents. They are still a part of the national consciousness. They were responsible for nearly 300 deaths.

However, the structures that failed in these towns were quite different from those in the Northeast. They were tailing Dams that were used for storing mining waste.   

Half of all the disasters occurred in a mining state

Although tailing dams are significantly fewer in number, they are responsible for a disproportionate number of tragedies.  

Nine of the 18 large dam accidents in Brazil between 1986 & 2019 were related to mining operations. Eight of them included the catastrophes in Brumadinho MarianaThis occurred in Minas Gerais which has been Brazil’s major mining hub since the 1800s.

Data visualization Brazilian dam safety population failures map EN

“Tailing dams are not just water reservoirs, but they also hold water. It’s quite different. It contains elements such as clay, starch and iron. It’s more dangerous and more unstable,” Evandro Moraes Da Gama, a professor at State University of Minas Gerais’s mining engineering department (UFMG), says. “There is no technique that can hold this in Brazil or anywhere else on the planet with 100% safety. 

Rafaela Baldi is a geotechnical engineering student at Rio de Janeiro State University (UERJ) who has a Ph.D. on dam safety. She says that most failures can be traced back towards poor management practices.  

Baldi says that mining companies are responsible for the lack in proper care as they seek to increase their extraction while lowering costs. She also says that institutions responsible for monitoring mining activities are also to blame.  

Brumadinho is Brazil’s most fatal dam failure.  

Executives from mine operator Vale and auditors of German company TV Sd who attested to the stability of the dam’s collapse are Answering to chargesAvoid neglecting structural problems 

“Unfortunately, this isn’t a rare occurrence. This is a common practice across Brazil. Mining companies put pressure on consultants, and they end up writing what is most convenient in the moment,” says Bald. 

Turning a blind eye to danger

The Mariana and Brumadinho dams didn’t collapse as high-risk structures. This is another aspect of Brazil’s dam problems: lack of information. It is not aware of the number of dams that exist on its territory, nor of their current state. 

Since 2010, information about all dams in the nation has been centralized in the National Dam Safety Information System, maintained annually by the National Water Agency (ANA).  

However, the data is not complete as ANA’s annual reports highlight. The database currently contains information on around 22,000 dams. The agency estimates that there are approximately 170,000 artificial water reservoirs in the country.  

For 57% of the dams in the system, no information exists to determine whether they are subject to legislation that outlines safety standards for structures above a certain size, risk level, or potential damage classification.  

Most of the 6000 dams which are subject to national safety protocols have not been certified. 73% lack the necessary safety or emergency plans. This means that they don’t give basic guidance on what to expect in the event of a natural disaster. 

Data visualization Brazilian dam safety dams by legal status EN

Fernanda Laus is the dam safety coordinator at ANA. She says information gaps should be expected when implementing a public policy. The safety monitoring database was created 12 years ago. 

She also said that gaps could partly be attributed to the patchwork nature of the regulatory system. Data are collected by 44 governmental agencies with varying levels and staff.  

“Resources are limited. Laus states that it is natural to start with larger dams but leave smaller ones for later. Laus adds that regulators are moving quickly to gather missing data. “But this is not the reality for all agencies. Some agencies simply don’t have the ability to do this for now. 

Edited and edited by Gianna Grn, Jennifer Collins

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