Study of the hydrological impact of the growth of a residential neighborhood on urban drainage – A case study at the city of Macaé, Rio de Janeiro, Brazil

Abstract

This paper aimed to study the drainage system of a residential neighborhood through a case study. Thus, a sensitivity analysis of drainage was carried out considering the progress of the urbanization process in the Imboassica district, in the municipality of Macaé, Rio de Janeiro. It was possible to evaluate the model’s response to different land use planning, represented with variations in the Manning coefficient and also in the Curve Number. The MOHID platform was used along with the OpenFlows FLOOD® software interface to elaborate scenarios with different soil characteristics, and distinct Digital Elevation Model (DEM) were adopted. In the first evaluation, three simulations (1, 2 and 3) were performed considering the natural topography of the terrain, using altimetry data obtained from the TOPODATA project of the National Institute for Space Research (INPE). Afterwards, the elevation quota represented in the Digital Elevation Model (DEM) was raised by 10 meters in the locations corresponding to the location of the houses and by 1 meter in the roads of the residential condominium, and then the three simulations (4, 5, and 6) were performed. The six simulations adopted the 10 years return period Rain Design. After that, another set of six simulations were performed, adopting the 50 years return period Rain Design. It was possible to observe that in the simulations considering the change in the elevations due to the presence to the houses and the road, the calculated value of the water depth increases in the drainage channels. The effect of the Curve Number changes was observed in the flood peak simulation, which is reduced due to the presence to greater vegetation. And finally, it was possible to observe the effect of the change in the Manning’s Coefficient, whose increase caused a delay in runoff.