Análise comparativa de métodos para o cálculo de precipitações intensas

Abstract

One of the difficulties encountered in the projects of drainage works is associated with intense rainfall maximum likely determination. One of the main solutions to characterize and estimate the intense rainfall is the use of intensity-duration curves-frequency (IDF) or daily rainfall disaggregation. In Brazil, daily rainfall data are more accessible and the breakout method is the most widely used. This method consists in obtaining coefficients relating the maximum 24-hour rainfall and rain a day. The coefficients of unbundling proposed by CETESB (1979) are widely used, however, Zuffo and Genovez (2000) point out that these coefficients can provide significant errors, and Abreu (2018) also States that the application of the method still lacks an evaluation in statistical terms. To verify the hypothesis of Zuffo and Genovez (2000) and Abreu (2018), this work aims to carry out a comparative analysis between the daily rainfall disaggregation methods and the IDF curve method through the test of the null hypothesis (H0) and alternate hypothesis (H1). The results showed that for the northern region, the method does not reject H0 under certain conditions of temperature and average annual rainfall while in the Northeast and Midwest, does not reject H0 for the calculation of maximum rainfall for short duration under series size and climate. In the Southeast, does not reject H0 for the calculation of maximum long lasting and intense in the South, 15 years of observations were insufficient to not reject H0. It is concluded that the adjustment coefficients of CETESB (1979) showed positive performance and noted that the size of the series, climate, temperature, average annual rainfall, altitude and regions interfere on the method.