In October 2023, Porto Alegre, the capital city of Rio Grande do Sul, had just experienced its most serious flood since the historic one recorded in 1941. At the time, to the disbelief of many, Brazilian architect and researcher Mima Feltrin said that, at any moment, Porto Alegre could experience a flood more intense than that eight decades ago.
“All it takes is winds to change, the conversion of the rivers in the escarpment, a series of climatic factors that could cause that same flood,” she said in an interview with Brasil de Fato Rio Grande do Sul, published on October 7, 2023.
Now that the waters of the Guaíba River have not only broken their 1941 record, but done so repeatedly, we spoke to Feltrin again. She has a degree in Architecture and Urbanism from the Pontifical Catholic University of Rio Grande do Sul (PUC-RS, in Portuguese), with an academic exchange program at the Universitat Internacional de Catalunya, Barcelona. She is currently working and studying areas such as public spaces, waterfronts and environmental disasters.
Read the full interview below
Brasil de Fato RS - On October 7, 2023, right after the floods that devastated the Taquari River Valley, 100 km from the capital city, you said in an interview with Brasil de Fato RS that Porto Alegre could have a flood like the historic one recorded in 1941. Where did that conviction come from?
Mima Feltrin - It came from my study on floods in Porto Alegre, in 2019, when I did my final project at PUC-RS. I was already working on floods in my thesis. So, to write it, I started researching different bibliographies and found studies by Professor Tucci [Carlos Tucci, a researcher in water system forecasting and warning and former professor at the Hydraulic Research Institute at UFRGS] who, in 2008, published an article called “Urban Waters”. In it, he provided data proving that the 1941 flood had different water peaks compared to previous floods. Based on hydrological calculations, he proved that floods similar to these and with the same or even greater intensity - like those of 1941 and 1967 - could happen at any time.
I gathered different sources of data. NASA can also predict this. Its platform, Sea Level Rise, provides parameters and quotas for cities, which enable us to make calculations that prove the magnitude of climatic events and corroborate Professor Tucci's hypothesis.
So, taking the data into account, I was able to state that a new flood could happen at any time. When we also have climate change, global warming and the ongoing deforestation of the Amazon, these events intensify the factors for new floods.
Your prediction seemed impactful, but in the face of what we're experiencing now, it's even conservative. What mistakes happened to make everything even worse?
Since its inception, Porto Alegre has had a very close relationship with Guaíba Lake. It is part of the city's history. It was through the lake that the Portuguese immigrants who colonized the central area of our capital city – the port area – arrived. It was called Porto dos Casais (“Couples Port”, in a rough translation) and later became Porto Alegre. With the economic and social increase through the port, there was a need to build a bigger pier and, to do so, they filled in a large part of the river's original bed.
That's the first mistake. We drastically changed the structure of the river, and the size of its mouth, which would help prevent floods today. When we landfilled a large part of the port on the 4th. Distrito [northern part of Porto Alegre], we completely changed the course of the water, therefore no longer being able to predict it.
Then, due to a lack – I believe – of urban planning, buildings were allowed to be built too close to the Jacuí River, such as the Castelo Branco and Edvaldo Pereira Paiva avenues. Even though we have dykes on the avenues to prevent flooding, we can see that there was no respect for the mangrove areas, the local fauna and flora which, when there is flooding, would help the water to drain away. Where we should have had nature helping the water to flow, we built using concrete.
In July 2023, Porto Alegre’s Mayor, Sebastião Melo (Brazilian Democratic Movement) ordered the cutting of more than 400 trees in Harmonia Park, located next to Guaíba. Why is Brazil going in the opposite direction of what many cities around the world are doing, replanting trees and greening their streets and avenues? How do decisions like this pose future problems for the city?
I was very frightened by Sebastião Melo's election. Since 2008, it has been proven that there could be a flood equal to or worse than that of 1941. And I was scared because I didn't see any mention of projects to prevent flooding or [to deal with] climate change, as if Porto Alegre had no chance of suffering from floods.
We could have a waterfront that proposes the “renaturalization” of this flora and fauna. It could be the Cais Mauá waterfront. This would include preserving the center [of the city] and the warehouses that are the city's cultural heritage. We could have an open-air park that would also protect against flooding, as is being done in New York with Rebuild B Design by BIG. There were several meetings with the population [of New York] to find out their needs. We see Porto Alegre with a completely opposite logic.
Where we could have parks, we have tall buildings with helipads, covering the warehouses’ view. Where we could have a very strong waterway system, given the potential that Porto Alegre has. When many cities around the world are tearing down viaducts, Porto Alegre is building more viaducts.
It scares me to think that the future of Porto Alegre is in the hands of a denialist city project. Where the population isn't even asked what it needs. Instead, they ask the city's big companies, which are totally silent on the current climate crisis we're experiencing today.
You've also said that, due to climate change and according to the simulation models available today, Porto Alegre will be underwater in 400 years' time. Tell us a bit more about that.
Through the platform I mentioned (Nasa's Sea Level Rise) we can see the situation of cities regarding sea level and how this level is projected to rise over the years. It's a calculation that can be made from this data. I made this calculation in 2019 and I believe that the current forecast is even more pessimistic.
Porto Alegre is 10 meters above sea level. According to NASA, the sea level in Porto Alegre is also rising (by) 2.5 centimeters a year. In 400 years, it will reach 10 meters.
In addition, projections by UN-Habitat [United Nations Urban Settlements Program] show that, by 2050, about 90% of the world's largest cities will be exposed to rising sea levels. So, the question emerges again: How are we preparing to solve this real problem that is already knocking on our door?
To give you an idea, using the same data provided by NASA, in 100 years' time Venice will be completely submerged. We can see that Brazil is a long way behind. Because Venice itself has already built a protection system because, for them, it's a much shorter timeframe.
But if we also compare Porto Alegre with New York, it turns out that in New York it [the flood] will happen in a thousand years. But New York's anti-flood plan has been under construction since 2014 and together with the population, while Porto Alegre is now suffering the aftershocks of floods. It's urgent to talk about it.
In recent years, the government – as happened under the Eduardo Leite (Brazilian Social Democracy Party) administration – has decided to loosen up and outsource its responsibilities for supervising businesses and instituting a kind of “self-licensing” in which entrepreneurs supervise themselves. In your opinion, does this improve or worsen the situation we're experiencing?
This tragedy that Rio Grande do Sul is experiencing is the result of a minimum state plan, which both [governor] Eduardo Leite and [mayor] Sebastião Melo defend. The minimal state doesn't prevent problems. We see disorganization in crisis management itself. The minimal state outsources its obligations.
In practice, to give you an example, when the Mauá Pier project was put out to tender, there were environmental impact studies and reports carried out by the companies. We see that even though the company that won the process carried out impact studies, its project did not seek to preserve or improve fauna and flora. Therefore, it is very difficult to leave the final responsibility in the hands of those who only foresee business profit. Our governments have not taken this climate emergency seriously.
We don't see a project by the federal government regarding the disasters happening in the Southeast, the South, the North and the Northeast regions of Brazil. I think this is a consequence of a whole society that disbelieved that climate change was going to devastate our territory. We need a general turnaround.
My degree of optimism is low because we first have to change the way we think, not treat the case of Rio Grande do Sul in isolation. The country is going to be hit by different disasters in different parts of its territory.
We need planning and projects that take these new times into account. Prefabricated solutions aren't going to help us. Each city has its own characteristics and each needs special projects.
We can't have the same solution for a project in Porto Alegre and another, for instance, in Canoas [one of the largest cities in Rio Grande do Sul hit by floods]. It's different, even though they are neighboring cities.
It's hard to have an optimistic outlook when it wasn't even admitted that we were prone to environmental and natural disasters accentuated by climate change, global warming and deforestation in the Amazon. A few months ago, half the country was debating whether the Earth was flat or not.
It's very difficult to be optimistic in times when you have to defend the obvious. You have to completely reverse logic. That logic of thinking that disasters happen eventually and are isolated events. [We must] Start believing in climate change. It's going to be a long-term process.
We can't take the same actions we've been taking, [such as] plans to provide for construction in riparian forests, in forested areas. It's a process where a country wants to deal with these disasters. We have the capacity and qualified researchers.
What about the recovery of the affected cities? Is it possible to think that, in places where the water reached two floors or more of the buildings – as in the Taquari Valley twice in seven months – it will be possible to rebuild the cities in the same locations they were?
It's not possible to rebuild cities in the same places they were. Most of them were built on the banks of rivers. There were no effective master plans to prevent this construction. Or there were – but they were violated.
We're even going to have to create a national bibliography on the subject. This was one of the great difficulties I encountered in my master's research. There was no national bibliography that could be consulted on disaster prevention.
You can't plan for 50 years from now but take into account 200, 300, 400 years from now. It's a huge job. It will depend on our governments and population on how they will deal with this catastrophe.
A post-disaster researcher, Joanna Dixon, already said, back in 2022, that the immediate start of reconstruction after the trauma can lead to mistakes in decision-making due to the lack of time to reflect on the best way to rebuild.
That's exactly what I think we have to take into account in this post-disaster period, that is, long-term solutions so that we don't suffer from floods again. There are already data, projects and studies that would certainly have minimized or completely stopped these floods.
Among the various options proposed after the 1967 flood, one was to open a canal to the Atlantic Ocean, in addition to other types of protective barriers. The one that was quickest to build and least expensive was chosen. That was the Mauá Wall. It was an immediate solution. I'm afraid that the same type of solution will be used now.
The thing is, when we suffer a disaster, the first steps we take are emergency measures, first aid, and then providing a solution. But the solution has to be thought out over time, over the long term, so that the right measures can be taken. I don't know if this will be considered.
The Mauá Wall has not only had its impact as a flood barrier but also ended up being a scar on the urban fabric. It separates the historic center and the population from the waterfront. In 2019, I did a survey interviewing people in downtown Porto Alegre. I asked them if they knew what was behind the wall. More than half of those interviewed didn't know.
We also saw that the pump system had not received maintenance measures since 2018. The sluice gates in the wall had not been maintained or restored for years. And they put sandbags in the sluice gates so they could withstand the waters of the Guaíba. That’s an immense disrespect the way this matter is approached. People's lives are put at risk and a sandbag is chosen as the solution.
This is the behavior of a city government that has been denying nature. It has been denying public areas and privatizing important areas, such as the Cais Mauá area. It wants to remove the wall to have a 1m20cm barrier. It's a good thing they didn't have time to do this, otherwise the damage would have been much greater.
Edited by: Rodrigo Chagas
