Modelo hidrológico e hidráulico para estimativa e delimitação de áreas inundadas: uma ferramenta de auxílio à elaboração de Planos Diretores de Drenagem Urbana

Abstract

One of the most critical issues in terms of urban drainage is related to channels overflow that drain urbanized sub-basins. Under these conditions, the flows induced by rainfall are amplified by the effect of urbanization, with anticipation of the peak times and increase in flow. When these flows to reach the talwegs from sub-basin, there is a transient effect of propagation of floods in channels macrodrainage. The overflow occurs when the depth exceeds the height of the chute. In such cases, the water invades the floodplain, creating areas of flooding that, as a rule, are defined after the occurrence of floods, for stains left on walls of surrounding buildings. The purpose of this dissertation is to present a numerical methodology to make predictions of areas affected by flooding in urban sub-basins. The proposed method is based on three fundamental types of models: hydrological, which establishes the relationship between precipitation and flow, the hydraulic, which calculates the flow inside the channel; and the terrain model used to estimate the flooded areas. The proposed methodology requires the characterization of the basin, the use and occupancy, the equation of rain and temporal distribution of the storm. The geometric characteristics of the channel should also be raised as well as the contour surrounding the channel. In applying, we used a sub-basin of the town of Rio Verde, GO. The methodology has utility in the preparation of Urban Drainage Master Plans, because it is possible to estimate flooded areas generated by several scenarios, such as urbanization intensification with occupancy of permeable areas, the reduction of time of concentration of basins, or the analysis of different return periods of rainfall. Changes in the characteristics of channels, such as height increase of the chute or the transversal section expansion with the construction of reservoir, and the effects of these changes in the reduction of flooded areas, can also be tested with this methodology.