HEAVY RAINFALL MODELS UPDATE FOR MUNICIPALITIES IN THE SOUTHEAST AND CENTRAL-WEST REGIONS OF BRAZIL

Abstract

Due to the climate change, it is essential to review and update heavy rainfall equations.  This study aimed to fit intensity-duration-frequency (IDF) equations for Brasília-DF, Belo Horizonte-MG, and Lavras-MG, comparing them with equations from the national scientific literature. Historical series of annual maximum daily rainfall were used, and the probability distributions Gumbel for Maximums and Gamma Two-Parameter were applied. The fitting evaluation allowed the selection of the most suitable non-parametric distribution for each municipality. The rainfall disaggregation method was applied for different return periods, generating the corresponding IDF curves. It was observed that for   Brasília and Lavras, longer return periods and shorter durations resulted in greater data dispersion compared to the rainfall intensities estimated by the compared references and the present study. This behavior was not observed for Belo Horizonte.  The fitted coefficients were: for Brasília, K= 816.70, a = 0.081, b = 8.990 and c = 0.704; for Belo Horizonte, K = 1076.16, a = 0.114, b = 9.783 and c 0.724; and for Lavras, K = 815.55, a = 0.137, b = 9.782 and c = 0.724. The models showed a coefficient of determination (R²) greater than 99.8%.