A recent article by Mayra Rosa in CicloVivo, the Brazilian sustainability news site, recently reported on the emergence of rain gardens in São Paulo (Jardins de chuva estão surgindo pela cidade de São Paulo). I therefore wanted to share a little of this article in order to show how a group of environmental activists is literally breaking new ground by breaking up asphalt and concrete to make Sao Paulo greener and more permeable.
In order to explain the issue, it’s important to know that during the time of São Paulo’s great expansion, the rivers which ran through the city were seen as a hindrance to development, and were paved over. One of the people most responsible for this ‘paradigm of transformation’ was the mayor Prestes Maia who governed between 1938 and 1945. He eliminated 4 thousand km of creeks, streams and their banks, a great resource which were considered great options for leisure in metropolitan centres such as Paris and London.
As you can see from this video above, which was recorded in Vila Madalena, a neighbourhood close to where Maria and I live, the impact is immediate and dramatic during heavy downpours. The water simply has nowhere to go.
A number of activists are attempting to overcome this problem by planting rain gardens. These are made by breaking up an area of concrete or asphalt which therefore creates an area for the water to enter. The gardens include plants which are of the varieties best able to absorb a large quantity of water in the rain season but which can still survive for long periods without water in the dry season. With a top level of stone or wood to prevent the soil being washed away, the gardens become self-sustaining with little need for maintenance.
The video above shows one example of a roundabout in a residential street being converted into a rain garden. The original article contains photographs of a number of others as well.
While many more rain gardens are required, this is one simple solution which if built into construction plans from the beginning, could really contribute to solving a major issue which affects the lives of millions of people who live in São Paulo and many other metropolitan areas which we created with little understanding of the relationship between humans and their natural habitat.