A influência das mudanças climáticas na estimativa de vazões de projeto através do método GRADEX.

Abstract

The increase in urbanization working in conjunction with climate change, nowadays, has intensified the problems arising from urban floods due to increased flows. Thus, rainfall series are used to estimate the flow of flood through synthetic models due to the scarcity of fluviometric data. This research aims to estimate project flows by the Gradex method for a macrodrainage channel in a scenario prior to current climate change, with the one used in the ANA series, and another that encompasses climate change, with the ESA series. The results show that the flows had their values increased by about 1.7 times, because for the first scenario the flow was 147.2 m³/s and for the second of 248 m³/s. The bottom width of the channel was about 60% higher for the most recent data. This was achieved by the manipulation of the historical rainfall series of ANA and AESA, application of the alternating block method as temporal distribution of intense rainfall, the CN method of the SCS as determination of the effective rainfall and the Santa Barbara method in the generation of hydrograms. It is concluded that the consideration of climate change in hydraulic dimensioning generates a considerable volume of surface flow, which makes it necessary to constantly update the IDF curves used. In addition, it is necessary to adopt flood control measures and formulate a rainwater drainage plan when it does not exist.