Vulnerability to Flooding in the City of Sao Paulo (PAP014839)

Código

PAP014839

Autores

Leticia Palazzi Perez, José Rodolfo Scarati Martins

Tema

Flood risk management in mega cities

Resumo

The city of São Paulo is the largest in Brazil, covering 1,500 km², population of approximately 12 million inhabitants ( IBGE , 2011) and watershed areas over than 80 % impervious. This level of soil sealing has a fundamental role in increasing the risks associated with flooding and mass movements due to increased runoff, taking the concept of risk as the product of the probability of the event, exposure, vulnerability and potential damage. This article shows the construction of curves flooding vulnerability for different basins in the city of São Paulo, according to the probability of the rainfall event, based on the historical analysis of such incidents over 10 years of records . Based on the data analysis of instantaneous rain records from the meteorological radar of Sao Paulo combined with 23 telemetric surface rain stations, 7 extreme rainfall events were selected and flooding incidents records were consisted by assessing those effectively linked to the rainfall event. Resulting valid data where fitted to the probability of occurrence in terms of return period and also the duration of the event, through GIS tools. The sigmoid-type resulting functions show vulnerability to floods of each studied basin for 2, 5 and 10 year return period events, and the associated spatial distribution of this vulnerability in São Paulo. It also presents the spatial analysis of occurrences of flooding within and outside the perimeter of the so called expanded center, which coincides with the areas under the influence of the main arteries of vehicular traffic and traffic restriction polygon, adopted in the city for urban mobility improvement. Data also point that, as in most Brazilian cities, the main road infrastructure of the city, mostly built on the floodplains of rivers and streams and often with closed sections structures, is vulnerable to events of 2 year return period.