Modelagem hidrológica da bacia hidrográfica do rio Bengalas, Nova Friburgo, RJ, utilizando o potencial de geotecnologias na definição de áreas de risco de inundação.

Abstract

This research focuses on the hydrological study using the potential of geotechnology into runoff modeling of the Bengalas Basin, whose main river, with same name, crosses the city of Nova Friburgo - RJ, in a south-north orientation. This city, one of the most important in "Região Serrana", suffers often with floods and landslides, which, historical data and recent events show that the inappropriate occupation of hillsides and margins of rivers are the highlighted and negatively affected areas. The methodology has basis in a GIS application, extracting information, which in turn, are input in the modeling phase, and enhancing the presentation of simulation results through maps. It is basically divided into three stages: "SIG", "Modelagem" and "Suporte à Tomada de Decisão/Simulação." This first study allowed to compose a geographic database with the physiographic features of the basin; the careful selection of a chain of mathematical modeling and its parameters with the hydrological cycle components, perform the calibration of the rainfall-runoff transformation model, Soil Conservation Service (CN) and simulate the transition of volumes generated by an effective precipitation in the Bengalas river, in order to identify and analyze the susceptible flooding areas in the central part of Nova Friburgo. A kind of this modeling has been used, mainly, in the water resource management, in which decision-making are based on results of computer simulations, helps to avoid a range of losses, such as material, financial and, especially, humans, that in this case, people who lives in areas susceptible to flooding. Analyzing the results, it was found that an area susceptible to flooding by a rainfall with a recurrence time of 50 years, the most critical studied, results in approximately 1.0 km², distributed in its 8.5km (central part of Nova Friburgo - RJ) which this bounded area has a great part with buildings.