Hydrological modelling applied to flooding assessment in the urban coastal city in Brazil

Abstract

The urban region of many coastal municipalities is marked by the growing process of urbanization of its marine river plain and presents great challenges related to the drainage of rainwater. This study seeks to verify the influence of the flood wave, coming from the upper part of the Macaé River hydrographic basin, in the flooding of the urban area, using MOHID platform, Land module, for the hydrodynamic simulation. The municipality of Macaé, located in the north of Rio de Janeiro (Brazil), has a dense network of tributary channels, built to drain more quickly the waters that accumulate in the floodplains during the rainy seasons. The current configuration of this system is insufficient to reconcile the current land use and runoff, and the floods impose several economic losses. Given this scenario, the Hydrographic Basin Committee of the region, through its Water Resources Plan, recommended studies on the theme, pointing out the need for a more detailed topographic description. The results of the model were compared with a rain that occurred in March 2018, which caused flooding in various points of the urban area. The methodology used can be applied in other municipalities with the same need.