Caracterização temporal e espacial dos alagamentos do município de São Paulo

Abstract

With the simultaneous population growth and urban expansion, natural and rural areas were occupied by the urban environment, with several problems arising from the interaction of the city with the environment, especially natural disasters. Among the natural disasters, flooding is one of the most common causes of environmental, economic and social impacts. Therefore, the objective of this work was to carry out the spatial and temporal characterization of flooding in the municipality of São Paulo - SP, during 2018, and to identify the factors of susceptibility of watersheds to flooding. For this, the study methodology was developed in three ways: (a) evaluation of the temporal distribution of the floodings, (b) evaluation of the spatial distribution of the floodings and (c) identification of physical and physiographic characteristics related to the highest occurrence of flooding. The temporal distribution was evaluated by the analysis of the relative frequency distribution of the occurrence of flooding throughout the year and the spatial distribution was carried out from the absolute number of floodings per subprefecture and water course in the municipality of São Paulo. A total of 264 floodings were observed, the highest occurrence in the period of greatest rainfall, comprising the months of January to March and November to December and the subprefectures of the Se, Lapa, Pinheiros and Santo Amaro. It was concluded that watersheds subject to monthly rainfall above 100 mm, with a compacity coefficient above 1.70, this index does not apply to flooding as it can be applied to floods, because it is essential that each factor is not evaluated individually but in a set that associated will influence the susceptibility of each basin, total geometric gradient above 160 m and average normalized difference vegetation index (NDVI) below 0.20, have high susceptibility to flooding.