Avaliação de riscos de inundação na bacia hidrográfica do Rio das Pedras - Pituaçu/Salvador-BA

Abstract

This interdisciplinary work is comprised in the area of environmental planning and urban planning and aims to evaluate the risks related to flooding, having as object of study the hydrographic basin of Rio de Pedras / Pituaçu in the city of Salvador-Bahia. In order to achieve this objective, a methodology based on the use of the Geographic Information System (GIS), called Map Algebra, was used, which allowed the spatialisation and hierarchy of the flood risk as well as the areas of susceptibility floods and social vulnerability of the catchment population. This methodology allowed the construction of the flood risk map by means of an algebraic operation, using the sum operator, between the flood susceptibility map and the social vulnerability map. The Flood Susceptibility map was elaborated considering three environmental variables: Land Use, Occupation & Coverage, Declivity and Hypsometry. The Social Vulnerability map was elaborated from three socioeconomic variables: Income, Demographic Density, and Types of Housing. As a result, it was verified that the river basin has very high and high susceptibility related to floods, near its mouth and in the central part respectively; with regard to social vulnerability, there was a condition of greater vulnerability in the high and intermediate part of the basin (Salvador's basin); with regard to flood risks, it has been found that in most of the basin they are low or very low; As for the high risks, they concentrated in the form of patches more expressively along the banks of the Pituaçu River and in the central and mainly lower parts of the Rio das Pedras / Pituaçu watershed.