In several cities in Brazil, the amount of rainfall has already surpassed the total accumulated for the rest of the year. Flooding, inundations, and landslides are commonplace news in regional newspapers. In this chaotic scenario, a study presented by the National Confederation of Municipalities states that, amidst the rains in the south and drought in the north, 5.8 million Brazilians have been directly affected by disasters in 2023, whether by loss of lives, displacements, or significant economic damages.
Unfortunately, the outlook is not promising either. The national version of the renowned IPCC climate change report, compiled by the Brazilian Panel on Climate Change (PBMC), has already warned that Brazil, along with other countries in Latin America, will not only experience rising temperatures due to climate change but will also witness a drastic shift in its rainfall patterns. In other words, here in the south, we better get used to the sound of rain on our windows, while the north should brace for historic droughts.
In this scenario, where climate change makes events increasingly unpredictable, the haphazard growth of cities further exacerbates the landscape of natural disasters. The issue of flooding, in particular, is becoming more prominent in urban centers. The lack of planning and inadequate drainage systems directly impact land use, leading to its subsequent impermeabilization.
This issue, of course, does not only affect countries in Latin America; it is a global concern discussed in seminars and debates worldwide. In this regard, each country has been addressing the issue in its way. In Europe, for instance, there is a noticeable significant investment in research and cutting-edge technologies to mitigate the catastrophes caused by flooding. However, despite having much to learn from other countries, Latin American cities have been contributing to the global landscape with creative and potent strategies, reflecting the unique geographical characteristics of this region.
When addressing the issue of urban flooding, the primary mitigation tactics that emerge are precisely those related to green infrastructure. Aligned with the concept of sponge cities, projects of this kind incorporate permeable pavements and reintroduce natural wetlands and aquatic landscapes to combat flooding while also providing recreational facilities.
The Rachel de Queiroz Park in the capital of Ceará, Brazil, stands out as an intriguing example. It is part of an initiative that, upon completion, will offer more than 200 hectares of natural spaces to the city of Fortaleza. This particular section serves as a municipal flood-prone preservation area, and the project incorporates drainage as a key structural element. Following hydrological studies, the proposal included the creation of nine interconnected lagoons designed to undergo a natural water filtration process, utilizing the nearby river and stormwater drains with the technique of wetlands. Pathways between the lagoons lead visitors to well-structured recreational areas with cultural, sports, and leisure facilities. In conjunction with planting over 600 species of native trees, the project effectively mitigated frequent flooding by alleviating stress on the stormwater drainage system, simultaneously offering a high-quality public space for the local population.
Using flood-prone areas as a strategy to mitigate urban flooding is intriguing, but it may not be a practical solution due to the unique circumstances of each city. Therefore, large expanses of public green spaces take the spotlight, as they inherently provide crucial soil permeability. In this context, extensive urban green corridors, such as those implemented in Medellín, Colombia, the Córrego Grande Linear Park in Florianópolis, Brazil, or the proposed Ecological Corridors in Bogotá, Colombia, represent strategies of varying scales and impacts. They all aim to bring (or preserve) vegetation within urban centers, increasing soil permeability and enhancing water absorption.
Continuing in the realm of green infrastructure, the creation of urban gardens, exemplified by an initiative in northern Brazil, and more subtly, green roofs, such as in the project at the Universidad de los Andes Civic Center in Bogotá, can be highlighted. Although not constituting a public green space like the previous examples, the green roof contributes to rainwater absorption and helps alleviate flooding issues in densely populated cities where green spaces are scarce.
In addition to floods triggered by rainfall, many Latin American cities also grapple with coastal or riverine inundations. Governments often turn to traditional solutions like beach nourishment or constructing seawalls to address these challenges. It is important to understand that both of these approaches serve as protective (preventive) strategies, yet current global discussions are placing growing emphasis on more adaptive water management measures. A clear example illustrating this shift is the Amphibious Membrane and City-Park project in Recife, Brazil. This initiative aims to establish an Ecosystemic Park on the urban oceanfront, going beyond the concept of purely technical containment infrastructure. The membrane would adapt to the marine terrain, shaped by both human intervention and natural processes such as marine currents that organically contribute to shaping the new territory, connecting through three interconnected parks.
When discussing this topic, it is important to highlight strategies that, while not primarily aimed at preventing floods, efficiently address the situation to minimize damage to the community. An intriguing example is the Cañales Skatepark in Mexico. The project’s architectural design considered the area's history of recurring floods. As a result, the entire covered sports area was elevated, guaranteeing that water would only reach the outer perimeter of the complex in the event of floods. This design choice prevents damage to the structure and ensures its proper functioning.
The LAMOCC Community Center in the Colombian Caribbean was designed to address emergencies caused by climate change, particularly rising sea levels and consequent flooding in the region. Resulting from a public competition, the project combines vernacular techniques (wooden structure and thatched roof) with contemporary methods (an elevated concrete foundation) to create a structure resilient to rising water levels. Additionally, the space serves as both a community gathering place and a refuge during episodes of flooding.
Green infrastructure, ecosystemic parks, or flood-ready architectures are just a few of the many strategies being applied on a regional or global scale. Nevertheless, it's important to note that specific anti-flooding strategies can vary from city to city based on local conditions, budgets, and available resources. Furthermore, a comprehensive approach that combines various techniques, considering both short-term and long-term solutions, is often the most effective way to address flooding in Latin American cities. This approach should also take into account collaboration among governments, local communities, and international organizations to successfully implement and sustain these strategies.
