Avaliação do impacto hidrológico devido à utilização de técnicas compensatórias de drenagem urbana, sobre modelo tradicional de dimensionamento de microdrenagem - estudo de caso no Campus Maracanã da Universidade do Estado do Rio de Janeiro (UERJ)

Abstract

In the context of climate change, caused by the increasing global atmospheric temperature and the change in precipitation patterns, urban drainage infrastructures designed according to the hygienist model have not been sufficient. To restore the conditions of the watershed prior to urbanization, especially regarding infiltration processes and natural storage of urban rainwater, investments have been made in unconventional techniques related to urban drainage. This study aimed to evaluate the hydrological impact of using compensatory techniques on the conventional drainage system in a contributing micro-basin within the Maracanã Campus of UERJ. To prepare the land use and occupation map, a photogrammetric survey was carried out with the aid of a drone overflight over the UERJ lot. After processing the images, it was possible to generate orthoimages for classification of the areas in a GIS environment. The University's drainage network was dimensioned using the Drenar software, based on the launch of routines in a CAD environment, projecting for a 10-year RT. A scenario was proposed using compensatory urban drainage techniques, with the use of five rainwater reservoirs, three permeable pavements and three infiltration trenches dimensioned for a 10-year RT. The five reservoirs resulted in a damped runoff of 149.96 L/s and used 4,174 m² of the UERJ basin's contribution area. Together, they have a storage capacity of approximately 226 m³, sufficient to meet non-potable demand for 26 consecutive days without rain. The three infiltration trench devices damped a flow of 75.00 L/s, considering a drainage area of 3,822 m². The permeable pavement technique used a catchment area of 5,446 m² and a flow damping of 195.93 L/s. The hydrological impact of using the techniques designed in this study on the drainage network in the UERJ basin, which discharges a flow of 2,041.66 L/s, would result in a reduction in the flow discharged of approximately 20.6%.