Identificação e avaliação de zonas de alagamentos urbanos na cidade de Natal, nordeste do Brasil, com o suporte de geotecnologias

Abstract

Urban floods motivated by heavy rains have caused significant loss of life and economic damage in several urban areas of the world. This flooding type have become frequent in many Brazilian cities. In Natal City, Rio Grande do Norte (RN) State Capital, Northeast Brazil, the urbanization process over the last four decades promoted significant soil sealing, which has reflected in numerous urban floods per year. This study aims to identify and evaluate areas susceptible to flooding in Natal, specifically in the region of Tirol, considering Digital Terrain Model (DTM), Digital Surface Model (DSM) of high precision, pluvial drainage system, historical records of flooding and hourly precipitations, in addition to reflecting the type of occupation of urban lots in the neighborhood. Methodological approaches were conducted and integrated into the Geographic Information System (GIS) environment, with the support of in loco high accuracy database of Global Navigation Satellite System (GNSS) for urban flooding analyses. The results showed that in the study area two topographic depressions in sectors of intense commercial and social activities stand out because they present geomorphological and anthropic characteristics highly favorable to flooding in events of Intense precipitation. Furthermore, the results allowed the generation of a superficial flow models with parameters of high applicability for the improvement of projects of urban drainage systems and urban management. This study also demonstrated that methodological approaches based on the use of Geotechnologies can subsidize risk management plans and reduce public expenditures with more effective works and emergency actions.