Urban floods: analysis of impacts in São Gonçalo (RJ) between the years 2005 and 2018

Abstract

In a scenario of evident environmental changes, the historical problem of the recurrence of floods and urban floods can become even more challenging from the point of view of the impacts caused, especially in peripheral areas of large cities. The objective of this work is, through searches of journalistic reports and the use of georeferenced Civil Defense occurrences, to analyze the repercussions of floods and identify the neighborhoods most impacted by these disorders throughout the municipality of São Gonçalo (RJ) between the years of 2005 and 2018. The methodology was divided into three moments: in the first, areas with a natural propensity for the occurrence of floods were delimited, that is, those close to river channels (50 m from each bank) and those where the terrain slope varies between 0 and 3%, followed by searches of journalistic reports and civil defense incidents, and finally the mapping of the most impacted areas. The results show the greater recurrence of floods in the central portion of the municipality towards the North in contact with Guanabara Bay. Areas where the soil suffers from greater waterproofing and the river channels are more uncharacterized, mainly in the Alcântara River basin, which accounted for 51% of all floods, 69.9% of homeless people, and 41.6% of deaths. Regarding rainfall totals, those exceeding 60 mm proved to be capable of contributing to 48.6% of floods and 77.5% of more serious situations involving homelessness or deaths.