By JORGE BARCELLOS*
Flooding as a museum theme reminds governments that they are responsible for the policy of protecting cities, whatever their ideology.
“Much wisdom from coexistence with rivers has been learned throughout the development of humanity”
(Carlos Tucci) Have we learned?
In Rio Grande do Sul, a group of left-wing intellectuals are reflecting on the basis for building a flood museum. We had floods and not floods because in the first there is overflow, while in the second, the river is at its predicted maximum. Flooding as a museum theme reminds governments that they are responsible for the policy of protecting cities, whatever their ideology. It is strategic at this very moment because Porto Alegre is experiencing the beginning of the electoral campaign for mayors and councilors. To the left is a workhorse. This imposes urgency on the project. But this is a problem.
Why? Because the issue of flooding is part of a larger problem, that of accidents in the contemporary world. I follow Paul Virilio's thoughts along these lines. The flood is part of a larger story of accidents. They are of various types: environmental, technological, fires, shipwrecks, air disasters, earthquakes. This requires its own museum. The flood is just one chapter.
This is what Paul Virilio showed in his work Unknown Quantity, an exhibition held at the Cartier Museum for Contemporary Art where for the first time he presented the Accident Museum thesis. So it would be appropriate here to defend the creation of a Museum of Accidents like this, which goes from the fire in the Renner building, to the fire at the Kiss Nightclub, to the plane crashes on Rio Grande do Sul soil (and they exist!) to the flood of 2024. This is possible?
Whatever the proposal, the first necessary action is to build a timeline on the topic of flooding. There are countless studies on the history of Rio Grande do Sul floods and better scholars of the subject than me, like Rualdo Menegat. But I understand that it is necessary to publicize the story of these tragedies that struck Rio Grande do Sul. This is the objective of this text: to publicize that floods are nothing new on Rio Grande do Sul soil, which makes the current authorities even more responsible for their inaction in the face of tragedy.
The best reference I found on the topic of the history of floods in the southern region was the study by Lucia Porto and Maria Ilgenfritz entitled Rivers in the city: floods in the urban evolution of the Metropolitan Region of Porto Alegre, published by the State Foundation for Metropolitan and Regional Planning (Metroplan) in 2001. The work, out of print, is not very accessible and few libraries have a copy.
In their introduction, the authors emphasize that floods were rare phenomena in the past of Rio Grande do Sul, occurring almost every 50 years. The population that gradually occupied the metropolitan region and the interior of the state was located along the rivers because they needed to benefit from the use of boats, the main means of transport. But they point out that since ancient times it has been known how to live with the risk of flooding.
From the ancient Egyptians who knew that riverside areas should be left free to our ancestors from Rio Grande do Sul who located churches in non-floodable areas, such as the metropolitan cathedral of Porto Alegre, “there are several canals built in the 19th century that provided a bed for drainage to the drought and another for the flood, which was forgotten in the Dilúvio stream project, in Porto Alegre, which ended up being silted up” say Porto & Ilgenlfritz.
Then the Gaucho problem began. With the rush to occupy urban spaces, the great development and unplanned occupation of cities in the 55th century led to the occupation of areas at risk of flooding. The cities of Rio Grande do Sul went from having an urban population in the range of 1970% in the 82s to 2000% in the XNUMXs. This resulted in the occupation of flat spaces close to uncontrolled rivers, which were responsible for major floods:
Porto Alegre was different due to the city's dike protection system. The authors say “floods from 1940 to 1968 were significant in the city. After 1970, when the protective dike system was built, flooding was insignificant.” The authors emphasize that it is necessary to understand the geography of cities, where two factors affect flooding. The first is the nature of rivers, that a river is not built by a single bed, in fact it has two.
The first is the smaller bed, which occupies most of the time (99%) and only spills over some years, and the second, the largest, the plains next to the rivers, called riparian areas which, when occupied by rivers in flood, generate floods. The second is the waterproofing of the soil promoted by the production of cities. Houses, sidewalks, streets, parking lots and parks are a problem for water flow “as the water cannot infiltrate, this additional volume flows into the drainage system towards the rivers. The increase in maximum flow is on the order of six times the pre-existing flow.
Urban drainage projects developed within the local scenario of each subdivision have as an outdated principle the exhaustion of all volume generated as quickly as possible through conduits or channelization of streams. This process generates a strong acceleration of maximum flows, flooding places where the drainage capacity is small. The process of increasing the capacity of canals throughout the city has become economically unsustainable”, say Porto & Ilgenlfritz.
The authors' interpretation is important to point out that, before investing in pipelines that can be ten times more expensive than local control, there is a lack of policy that analyzes the capacity of the basins as a whole and concerns itself with infiltration conditions. The effects of urbanization, in addition to causing floods along the river, called “downstream”, deteriorate the quality of rainwater by washing the streets, sediment and garbage that flow into the drainage system.
This is what we saw when, inadvertently, Mayor Sebastião Melo instructed the population to place trash in the streets, and soon after, with the return of rain, a series of blockages followed in the Cidade Baixa and Praia de Belas neighborhoods. Arroio Dilúvio is another example of this problem, since as its headwaters become urbanized, the effects of floods tend to be transferred to the headwaters of the river. Around 57 thousand cubic meters of sediment are deposited there per year, in addition to urban waste and untreated sewage, contaminating water sources and reducing water availability.
According to Carlos Tucci, from the UFRGS Hydraulic Research Institute and author of the work's presentation, it is no longer possible to continue indiscriminately waterproofing the city's soil, channelizing streams and sweeping our sanitation problems under the carpet “the development of occupation planning of risk spaces through flood zoning makes it possible to live with riverine flooding in areas that the city's protective dike does not cover, as in the case of the metropolitan region. Institutional planning to control the source of the impacts of drainage, solid waste and sewage is essential for sustainable urban development”, he concludes.
End of the 19th century and beginning of the 20th century
Porto & Ilgenfritz remember that the history of the metropolitan region is linked to the natural outlet for the state's production, the Guaíba and Lagoa dos Patos, and the navigable rivers were chosen to give access to the municipalities that formed the state in the 1913th century: Rio Grande, Rio Pardo, Santo Antônio da Patrulha and Porto Alegre. That is why it is essential to understand that our colonization occurs from watercourses. Only the inclusion of the railway axis will change this destination: Canoas, Esteio and Sapucaia were places where three railway stations were installed. The works against floods were late: between 1920 and XNUMX, the access channel to the port of Porto Alegre was dredged, when the sand removed was used in the landfills that were used to establish the port area. The city begins to modify the limits of the river.
In addition to another flood that hit the city in 1847, the authors point to the year 1873 as a major flood. It began on Friday, October 3, interrupting the tram line to Menino Deus, invading houses and covering the warehouse on Rua 7 de Setembro. As in the current flood, citizens were transported using canoes in that neighborhood and the municipality organized donations for those affected. “It rained, it rained, which was something we had never seen before. The river began to flood, but it was not scary in the first few days, but since the great forces of water began to descend the mountains, the flood was pronounced in an astonishing and frightening way”, quote the authors in an article published in newspaper The reform.
The flood also reached São Leopoldo and Canoas. Then, the flood of 1881 hit the opening of the Brazilian-German exhibition and after that, the flood of 1897 prevented the races in Prado Navegantes and collapsed the Stone Bridge on Caminho da Azenha, filling the Arroio Dilúvio, which had not yet been channeled and flooding Menino again. God.
In 1905 and 1912 floods were also recorded in the city, first in August, and then from May to September, like the current flood. Porto & Ilgenfritz state that “in the capital, the stream overflowed, the Guaíba threatened, the Gravataí left its bed and Campo da Redenção was underwater. Even worse: at that time there was a Public Cleaning Service, carts that collected fecal matter and dumped it in Cristal. Due to the flood of Guaíba, this ended up having to be done at Praia de Belas cantos Botafogo”. In 1914, another flood, considered by Correio do Povo and the intendant José Montaury as the biggest since 1873, hit the city, reaching 2,6m in the Works Secretariat warehouse, 20 cm less than that of 1873. Everything up to the street Volunteers of the Fatherland became a river.
the 1920's
From the 1920s onwards, several transformations affected the state and municipalities. With the takeover of the railway with the creation of Viação Férrea do Rio Grande do Sul, Porto Alegre became the state's nerve center and the Navegantes neighborhood, located in the north zone and on the riverbank, revealed itself to be completely vulnerable to floods. Mayor Otávio Rocha carried out reforms that cemented the ground, but at the same time he created the Hydraulic Moinhos de Vento and expanded the water and sewage network.
In September 1921, rains hit the region, and especially Vale dos Sinos, Montenegro and São Sebastião do Caí were invaded by water. The Jacuí, Sinos, Taquari and Caí rivers were flooded and in Canoas there was water even in the center and there was no electricity for two days in São Leopoldo. In 1928 more rains and one hundred blocks were under water in Porto Alegre where 30 thousand people had to leave their homes. The São João neighborhood was flooded and Cia Carris interrupted trams to the region. Montenegro recorded the biggest flood, with the Caí river reaching 7,40 meters above normal level. There, the flood reached the center, Rua Ramiro Barcellos to Cais do Porto, when the city was without electricity for two days.
the 1930's
In September 1936 new rains hit the state. Now, São Jerônimo is underwater, beyond bridges and bridges. The rain arrives in Porto Alegre on the first of October, the stream leaves its bed and the Menino Deus and São João neighborhoods are flooded. A week later the flood reaches a maximum of 3,12 m.
Porto & Ilgenlfritz says that “on Ilha da Pintada, residents were on alert, as the river threatened to invade their homes. In the city center, water invaded the Post and Telegraph depot, damaging postal services.” The rain also hit São Leopoldo, preventing traffic and communication in the state. In Canoas, the overflow of the Gravataí River isolated the city and in Montenegro many riverside houses were abandoned.
Decade of 1940
While the world was going through the Second World War, in Porto Alegre another was going on: the flood of 1941. From April 10th to May 15th of this year, the rains began, and 15 days were uninterrupted. 15 thousand houses were affected and 700 thousand people were left homeless “cinemas closed, schools went on forced holidays, newspapers stopped circulating”, say Porto & Ilgenlfritz. Porto Alegre spent almost a month without drinking water and electricity.
After the tragedy, the municipal, state and federal governments were united in accepting their obligation to take precautions so that it would not happen again in the future, unlike in 2024. At the time, studies predicted another flood, the next day or in 370 years. For this reason, in 1949, the first part of the Flood Protection System was completed, protecting the polder (plain protected by dikes) Airport and pump house number 6. But the completion of BR-116 a year earlier had caused the urban population to grow on the side of the road.
The scenes seen today and in the 1941 flood were the same: the center transformed into a river, water in the Public Market, Avenida Borges de Medeiros and nearby streets. In 1941 we went from 110 mm of rain to 678 mm in that period. Cities in the metropolitan region such as Canoas, São Leopoldo, Novo Hamburgo and São Jerônimo were affected. In the latter, 2/3 of the city was underwater. Porto & Ilgenlfritz cite the testimony of Edmundo Fróes, who lived on the ground floor in front of the gas meter and had his grandfather Haroldo Azambuja living on the upper floor of his house “the gang and I took a boat and went to rescue my grandfather who was lying in bed, on the second floor. It was an adventure,” he says.
Several cities were left incommunicado, food was rationed, classes were suspended, electricity was cut off, house septic tanks stopped working and looting began. When we see the security problems in Bairro Sarandi today where people prefer to stay at home rather than go out because of robberies, we see that this is a recurring problem. When we see fights and the use of violence in shelters that are supposed to protect the population, it is again the problem of safety in calamity situations that returns “water does not choose the time to take its place”, say Porto & Ilgenlfritz. The Mauá wall, a concrete curtain that serves to protect the city, will only be completed thirty years later, in the 1970s.
The 1950s
The 50s saw the shift from rail and water transport to road transport. There was no other place for the poorest populations to settle than the banks of the rivers. For Porto & Ilgenlfritz “the floods that now and then punish municipalities in development or in the process of creation, are largely credited to the deforestation of Serra Geral, a true lung of the state.”
In April 1956, a new flood hit the capital and the regions close to the Dilúvio stream, in Passo das Pedras, Passo da Cavalhada, Bairro Navegantes and Tristeza suffered from the overflow of streams. This flood revived, like the current one, memories of the 1941 flood and the press reported, according to Porto & Ilgenlfritz that “it had not rained so violently in a period of 15 hours in Porto Alegre for 24 years”. Canoas and Gravataí also suffered the effects of this flood.
Decade of 1960
At this time, the industrial expansion of the region boosted the development of cities such as Sapucaia, Alvorada and Cachoeirinha, municipalities that, like Viamão, Gravataí and Guaíba, contributed to a tree real estate offering new, large and cheap housing developments “which often appeared in places they shouldn't be, in wetlands or floodable areas, lands that were already condemned for human occupation. Lands that had the function of regulating the environment, serving as a buffer, creating the “sponge effect” when the water appeared in quantity to take back its place”, say Porto & Ilgenlfritz.
Today, with the floods, the program Fantastic da Globo network announces Chinese architect Kongjian Yu’s “sponge cities” project as a solution. Now, local technicians were already aware of the idea but could do nothing when the Banhado Grande in Gravataí began to be drained by the DNOS, which was only suspended in July 1979, when a public security opinion ordered the suspension of drainage “around 20 years of reduction and deforestation in the area were perhaps most responsible for the floods that occurred in Gravataí, Cachoeirinha and Alvorada", say Porto & Ilgenlfritz.
In August 1965, another flood occurred and Porto Alegre was hit. The situation in São Leopoldo was even more serious, with flooding in 16 neighborhoods and more than 33 thousand people affected and six thousand homeless, people were left in the FENAC pavilions. Shoe industries were hit in Campo Bom and Canoas, in Vilas Niterói, Matias Velho and Rio Branco, nothing different from what happened in the 2024 flood.
In Porto Alegre, the Navegantes neighborhood and Vila Dona Teodora were underwater. The protective dike partially gave way. We have known since then about the fragility of the dikes. Why aren't dikes made bigger and more resistant? In September the rains returned, the so-called “São Miguel rains” and again the suspension of classes, villages and neighborhoods flooded, reaching 35 kilometers of water, 1/3 of the municipality at the time, 18 industries and 80 commercial establishments with losses.
The rain also hit Esteio, with flooding of towns in low-lying areas such as São José and the transformation of Avenida Presidente Vargas, one of the city's main avenues, into a river. In the following years 66 and 67, flooding also reached Porto Alegre, causing damage to Vilas do Guaíba and the death of an eleven-year-old boy. This last year the flood hit the metropolitan region more, with rain in São Leopoldo, Alvorada, Campo Bom and São Jerônimo. And, as in the 2024 flood, several road sections were interrupted: between Sapucaia and Gravataí, Viamão and Cidreira, Montenegro and Taquari, and Gravataí and Taquara.
Decade of 1970
The drainage of Banhado Grande, in Gravataí, impacts the construction of BR 290, whose construction was almost not completed due to the floods that interrupted the work. Backwater basins, properties of streams and rivers, are occupied to create subdivisions next to the industrial district of Gravataí. The first major flood occurred in July 1970 in São Leopoldo, with the Sinos River 5 m above normal, with the right bank overflowing and ten villages flooded.
In July 1976 it was Viamão's turn, with floods that destroyed 80% of horticultural production. In the same period it was Novo Hamburgo's turn, where rain forced the Health Department to draw up vaccination schemes and shelter, once again, homeless people in FENAC pavilions. Porto & Ilgenlfritz says that “a constant danger begins to silently haunt the Metropolitan Region: flooding, caused by drainage problems, lack of planning and, in many cases, lack of population awareness”. In 15 days we had 351,4 mm of rain, one of the worst measurements since 1941.
The 1980s
Again, in May the rains began and in August 1983, a flood occurred that forced the iron gates of the Mauá wall to be closed for the first time. According to technicians from the National Institute for Space Research (INPE), it was also the beginning of the demonstrations of El Nino. Around 29 thousand people were left homeless, 3 thousand in the Jacuí Delta region alone.
Social movements are beginning to demand solutions from public authorities for the floods of the Caí, Taquari, Jacuí and Sinos rivers, which rise sharply with each flood, say Porto & Ilgenfritz. In São Leopoldo, 7 people from the same family die in a landslide in a gravel deposit in Morro de Paula, in São Leopoldo. David Ianosgrodski, then director of DMAE, decided together with João Dib to act and “the two hit the hammer and Porto Alegre dawned with the city gates sealed”.
The turn of the century
Only in 2002 would we see another significant flood in the capital, with around 2,46m and in 2015, with water reaching 2,94m. The 2024 flood is being experienced as a tragedy: its characteristics, causes and problems are known and follow the history of floods in Rio Grande do Sul. They involve precariousness of the flood protection system, precariousness of public services, policies that facilitate deforestation, abandonment of Civil Defense funding, subdivision of areas that should be used for flood waters. The main one is the neoliberal development model, which stitches and promotes all of them.
There are many lessons from floods throughout history: they are products of the detachment of urban development policies from environmental management; the massive occupation of inappropriate areas of urban land; the precarious disposal of solid waste and the disarticulation of educational programs, among others “today we are aware of the need to change paradigms in the urban-environmental management of cities, especially with regard to drainage systems. A set of actions must mitigate its effects, prevent others and consider that floods are recurring natural phenomena and, therefore, must be considered in all planning and forms of intervention”, say Porto & Ilgenlfritz.
This new paradigm includes the incorporation of watercourses into the urban landscape, reforestation, control over the waterproofing of urban areas, incorporation of open public areas to buffer rainwater and sanitation of basins. Thus, in the upcoming municipal elections, the Left Front must present programs that propose a policy integration pact where “drainage constitutes a paradigm of fundamental importance in the urban and environmental qualification of the city”, in the authors’ terms.
Jorge Barcellos, Historian, he has a doctorate in Education from UFRGS and a retired member of the Porto Alegre municipal legislature. Author, among other books, of Education and Legislative Power (Authors' Club).
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