The extreme rains and floods have become increasingly frequent in Brazilian cities, intensified by climate change and accelerated urbanization. In this context, specialists propose the renaturalization of urban rivers as a key strategy to increase the resilience of territories.
Urban landscaper Cecília Herzog, a member of the Network of Nature Conservation Specialists (RECN), warns that the development model that channeled rivers and waterproofed the soil with asphalt and concrete has worsened the effects of the rains. “Water does not disappear. It will always seek the lowest points and can flood the flattest areas,” she explains.
How renaturalization works
The recovery of rivers involves returning some of their original characteristics: open courses, riparian vegetation, and permeable soils. This allows water to infiltrate, be temporarily retained, and flow more evenly, reducing the impact of intense rains.
The strategy must be complemented with an urban landscape requalification, including:
- Expanded green areas.
- Natural drainage systems.
- Permeable soils that slow runoff.
Experiences in Brazil
- São Paulo: the future Bixiga Municipal Park plans to reopen part of the Bixiga stream, preserve springs, and expand green areas. The project is the result of more than 40 years of social mobilization.
- Rio de Janeiro: the Municipal Secretariat of Environment and Climate coordinates a working group for the requalification of the Maracanã River, based on natural solutions. In March, an alliance was signed with the Institute of Architects of Brazil to launch a public project competition.
A new urban paradigm
Architect and urban planner Juliana Baladelli Ribeiro, from the Boticário Group Foundation, points out that renaturalization is part of a new urban development model. This includes:
- Green roofs.
- Rain gardens.
- Vegetated ditches and small retention basins.
- Extensive afforestation and structures that promote infiltration and evapotranspiration.
In addition to reducing floods, these solutions help mitigate heat waves, which are increasingly frequent in cities.
Climate adaptation: a local challenge
The specialists agree that isolated measures are not enough. Adaptation requires integrated and planned actions according to the reality of each territory. “It will be necessary to return to the city areas with living soil and native vegetation, capable of performing ecological functions that are currently impaired,” says Juliana.
Cecília Herzog adds: “Adaptation to climate change is always a local challenge that must be faced in each territory.”
The renaturalization of urban rivers is consolidated as an essential strategy to face floods and build more resilient cities. By recovering watercourses and reintroducing green infrastructure, Brazil advances towards an urban model capable of coexisting with the impacts of climate change and ensuring quality of life for its inhabitants.
