Gestão das águas pluviais urbanas e elementos da infraestrutura verde: estudo de caso da Bacia Hidrográfica do Rio Morto, Rio de Janeiro

Abstract

The increasing of the magnitude and the frequency of urban flooding is one of the consequences of changes in the natural environment. In order to restore the pre-urbanization basin conditions, especially the natural processes of infiltration and storage, it has invested in unconventional techniques related to urban drainage. In this context, hydrological-hydraulic modeling presents itself as a relevant methodology for the sustainable storm flow management, since it allows the simulation and creation of scenarios of flow control devices. The main objective of this dissertation was to verify the hydrological-hydraulic behavior of Morto river catchment before the simulation of the green roofs implantation with the support of the Storm Water Management Model (SWMM). The catchment is located in the lowlands of Jacarepaguá, in the city of Rio de Janeiro, and was constituted as experimental and representative. The application of the SWMM model involved the individual and simultaneous calibration of runoff and groundwater parameters for the events of December 2008 and June 2010, resulting in three possible sets of adjusted parameters that were used in the validation and simulation of scenarios. The validation of the model was made for April 2010, considered as one of the most critical events recorded in the region. The statistical coefficients R2, NSE, RSR and PBIAS were calculated to evaluate the effectiveness of calibration adjustments and model validation. The results were considered satisfactory, according to the literature. The simulation of scenarios with green roofs was done for the sub-basins 36, 37 and 43 for the event of April 2010, considering that the entire coverage area of the buildings of these sub-basins were replaced by green roofs, corresponding to 20%, 25% and 50% of the total sub-basin area, respectively. Although it was verified that the implantation of the green roofs did not revert flooding in the stretches of the rivers within sub-basins in which it were verified extravasation of the channels in the current conditions of soil use and occupation of the ground, it was verified that in all the simulations, there was reduction of the peak flow and of the flow generated in each sub-basin. In relation to the peak flow, an average reduction of 11.4%, 14.6% and 3.60% was observed, for the sub-basins 36, 37 and 43, respectively, whereas for the volume drained, an average reduction of 9.3%, 10.0% and 3.0% was obtained. The scenario with the insertion of green roofs jointly in these sub-basins caused a slight reduction of the peak flow in the outlet of the Morto river catchment of the order of 1.4%.