Study of Vulnerability to Flood in Ribeira Valley - São Paulo/Brazil (PAP014822)

Código

PAP014822

Autores

Briane Carla Coppi Ferreira, María Cleofé Valverde Brambila

Tema

Urban Floods

Resumo

The Ribeira Valley is located in the basin of Ribeira Valley at the east of Paraná and the southeastern of São Paulo in Brazil. This region has a history of recurrent floods, causing huge financial losses to the poorest people, including deaths of persons residing in the risk areas, as well as material losses. In this paper is proposed to identify the municipalities with greater vulnerability on the occurrence of floods, based on social indicators (socioeconomic, demographic and urbanization and sanitation) and hydro-climatic. The municipalities studied were Eldorado, Jacupiranga, Juquiá, Registro and Sete Barras. The components of hydro-climatic indicators used were rainfall and flow (daily data). Thus, were used the percentile 99 (P99) to represent the maximum daily data that are associated with the occurrence of floods. The components of social indicators were population density, population in rural and urban areas, urbanization, rate of growth, wealth, poverty, education, longevity, illiteracy, birth rate, water supply and garbage collection. The methodology quantifies the vulnerability index for groups with various components associated to each indicator. Furthermore, the indexes of social and hydro-climatic vulnerability were found and the both index related given rise to general index of flood vulnerability (GIV). This study emphasizes the contribution of social aspects to increased vulnerability to occurrence of the flood event in the Ribeira Valley. The results showed that the Juquiá municipality had the highest index of social vulnerability, because Juquiá exhibited the lowest water supply service and garbage collection, as well the highest illiteracy rate. Eldorado showed the second highest index of social vulnerability. Registro municipality showed the highest index of hydro-climatic vulnerability, because Registro got the highest P99 of rainfall and flow, also followed by the municipality Eldorado. By this mean, were verified in Eldorado with highest GIV, since this municipality showed high levels of poverty rate, longevity and illiteracy beyond the maximum P99 precipitation and flow, when compared to other municipalities. The low purchasing power due to poverty, results in more precarious houses and therefore more vulnerability to collapse in case of flood. Besides that this people tends to inhabit in areas with high risk of flood due to low cost land. With this result it was possible to identify some causes of the biggest impacts on the occurrence of flood in Eldorado, as the number of affected and displaced persons, when compared to other municipalities. Importantly, the indexes of vulnerability are synthetic, dynamic and relative. Therefore, for further study of vulnerability is necessary to locate specific areas in each municipality.