Extreme rainfall and flooding have become increasingly frequent in Brazilian cities. In this context, the renaturalization of urban rivers is one of the strategies experts advocate to help cities adapt to the impacts of climate change. Restoring and reopening waterways can make these areas more resilient.

Urban landscape architect Cecília Herzog, a member of the Network of Experts in Nature Conservation (RECN), says river restoration is an urgent measure given the current climate scenario.

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According to her, the development model that channeled rivers and covered the soil with asphalt and concrete has exacerbated the effects of rainfall.

“It’s important to remember that water doesn’t disappear. When it rains, it always flows to the lowest points and, at some point, can flood them, especially in flatter or low-lying areas,” Herzog said.

With fewer permeable surfaces, water runs off more quickly, increasing the risk of flooding. In this context, river restoration must be accompanied by a broader revitalization of the urban landscape, including the expansion of green spaces and natural drainage systems. Permeable soil helps slow runoff.

“Water seeps into the soil, is retained for a while, and then continues its course in a more balanced way. In open rivers, with their natural course and riparian vegetation, the impact of rainfall is much smaller,” the landscape architect explained.

Ongoing projects

This understanding is beginning to gain traction in Brazil. In São Paulo, the future Bixiga Municipal Park envisions reopening part of the Bixiga stream, as well as preserving springs and expanding green spaces. The project is the result of more than four decades of mobilization by civil society.

In 2024, the city council approved the allocation of the land for the creation of the public space, and in January this year, the city launched a national public competition to define the design of the future park. The result is expected to be announced in May.

In Rio de Janeiro, a working group coordinated by the Municipal Secretariat for the Environment and Climate is studying the rehabilitation of the Maracanã River through nature-based solutions. Researchers from public and private universities are participating in the initiative.

The proposal includes measures to restore some of the river’s original characteristics and expand the region’s drainage capacity. In March, a partnership was established with the Brazilian Institute of Architects (IAB-RJ) to hold a national public design competition for the renaturalization project. No date has yet been set for the call for proposals, but it is expected to be released later this year.

New standards

Architect and urban planner Juliana Baladelli Ribeiro, project manager at the Boticário Group Foundation, emphasized that renaturalization is part of a new urban development paradigm.

“This concept also includes the implementation of green roofs, rain gardens, vegetated swales, small retention basins, extensive tree planting, and other structures that allow for temporary water retention, facilitate infiltration into the soil, and promote evapotranspiration by plants,” Ribeiro noted.

In addition to reducing flooding, these solutions also help mitigate heat waves, which are becoming increasingly frequent in cities.

Experts emphasize that isolated measures will not be sufficient in the face of increasingly intense extreme weather events. Climate adaptation requires integrated actions tailored to the reality of each territory.

“It will be necessary to create a system for revitalizing the urban landscape. The idea is to restore to the city areas of living soil and native vegetation capable of performing important ecological functions that are currently compromised,” the architect stated.

“This may include sunken areas designed to collect rainwater and various types of green infrastructure, ranging from small-scale interventions to larger projects, depending on the characteristics of each city. Adapting to climate change is always a local challenge that must be addressed in each specific area,” Herzog added.

Brazil’s Environment and Climate Change Minister Marina Silva stepped down from her post Wednesday (Apr. 1). This was her third term in the position, all appointed by President Luiz Inácio Lula da Silva.

Like other ministers, she is leaving office to run in the upcoming October elections.

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The minister took stock of her 39-month tenure, from January 1, 2023, to April 1, 2026. In her speech, she addressed Brazil’s return to leadership on the global environmental agenda, presented data on the reduction of deforestation in threatened biomes, and discussed the ministry’s institutional recovery.

“When we arrived, in January 2023, we found an organization that needed to be rebuilt in terms of its political, ethical, technical, administrative, and operational capacity. Since then, we have revitalized Brazil’s environmental governance by adding more than 1,557 staff members to the ministry’s system,” she declared.

During this period, she said, the ministry’s annual budget more than doubled – growing by 120 percent, from BRL 865 million in 2022 to BRL 1.9 billion in 2025. “Institutional reconstruction means people, budget, governance, and execution capacity,” she added.

The budget increase and the recovery of the ministry and its affiliated agencies have yielded results, she argued.

“In 2025, compared to 2022, deforestation fell by 50 percent in the Amazon and 32.3 percent in the cerrado, preventing the emission of 733.9 million tons of CO₂ equivalent. In the most recent cycle of alerts, from August 2025 to February 2026, there was a further reduction of 33 percent in the Amazon and seven percent in the cerrado.”

“If we continue at this pace, even during such a challenging period, we stand to achieve the lowest rate on record,” she said.

With expanded teams and increased financial resources, greater action was taken in the most threatened areas. From 2022 to 2025, Brazil had 3.4 million hectares undergoing native vegetation restoration. The minister also reported that, in the same comparison, the area covered by illegal mining in the Amazon was reduced by 50 percent.

In addition to providing an accountability report and presenting results, the address marked the handover of the ministry’s helm to João Paulo Ribeiro Capobianco, the ministry’s current executive secretary. The appointment, Minister Marina Silva said, will ensure “the continuity of the policies adopted by President Lula’s administration in recent years.”

She said she views “political action as a service” and stated that she is “neither optimistic nor pessimistic,” but “persistent.”

In her view, “there is no civilization if denialism prevails. If it prevails, perhaps there won’t even be a planet.”