On Monday of this week it had rained all night and two of the largest rivers in Sao Paulo burst their banks.
Just over a hundred years ago, Sao Paulo evolved from what had been an indigenous settlement in between two rivers into a sprawling metropolis which now supports 20 million residents.
The indigenous community had built their settlement on top of a hill because the rivers had a tendency to flood and the first European settlers followed suit, essentially evicting the previous occupants from their land.
As demand for land increased, the poor were left with little option than to occupy the spaces on the flood plains and consequently were the victims when the rivers flooded.
The flooding of urban areas was an unsanitary process, so city planners decided to canalise what had previous been beautiful meandering rivers into straight channels, bordered by multi-lane highways.
Other cities such as Moscow, Vienna and Paris and created train, tram and subway networks encircling the city but in Sao Paulo the lobby of car manufacturers such as Fiat, GM, Ford and Volkswagon was very strong so mass transit systems were abandoned in favour of large avenues designed for car use which bordered and, in some cases, covered the rivers they followed.
As a result, many of the rivers in Sao Paulo have become invisible to the public, hiding the polution and waste which flows through them every day.
The rivers Pinhieros and Tiete and relatively slow flowing rivers and soon begin to smell very badly due to the effluent which accumulates.
When the rivers do inevitably flood, despite various attempts at flood prevention schemes, it understandably causes, not just chaos on the roads which border the rivers and occupy the flood plains, but also dangers to public health and sanitation.
Sao Paulo’s rivers have always flooded but the problems they cause are a consequence of urbanisation and poor planning based on the financial interests of the car manufacturers rather than the interests of the majority.
If you are interested in learning more, and you speak Portuguese, then there is and interesting documentary called Entre Rios which examines the issues surrounding the urbanisation of Sao Paulo.