Vulnerability and risk in an urban settlement in the Tietê river floodplain in the São Paulo municipality (SP)

Abstract

The peripheral expansion of great urban centers is characterized by the occupation of fragile areas in terms of geological and geotechnical parameters by an economically and socially disadvantaged population. The result of this interaction is the emergence of risk areas, which are very complex and present serious problems, requiring different responses from public authorities and an effective risk management relying on specific tools to assist in the decision-making process. In this context, this study aims to determine the social vulnerability, hazard and risk associated with flooding in Jardim Pantanal, an urban settlement frequently and effectively affected by flooding, located on the floodplain of the Tietê River, in the city of São Paulo. The social vulnerability index was obtained by adding up the factors related to human well-being that influence individuals exposed to and affected by a hazard, according to data from 2010 Population Census, by IBGE. The values related to the hazard are here called “level of susceptibility to flooding (NS)” and refer to the predominant elevation in each sector of the area. Using the correlation of these indexes obtained by geoprocessing techniques, it was possible to determine and prioritize areas of higher or lower risk of flooding. In general, the sectors inhabited by the most vulnerable groups are also the closest to the river floodplain, therefore, highly susceptible to flooding. Altogether, more than 10 thousand people are at high risk of flooding, and more than half of which are women and approximately 2,500 are children. Poverty is also an important factor for those living in these sectors, making their access to clean water, sanitation, infrastructure and safe shelter more difficult. This methodology, which can be applied to other similar situations, can be used to develop risk management criteria, mainly regarding planning and prioritizing actions. Other variables should also be tested in further studies.