Hietogramas obtidos a partir de relações IDF para as mesorregiões sul/sudoeste e Campo das Vertentes, MG

Abstract

The rainfall intensity curves are representations of the temporal distribution of rainfall, important in the entry of rain-flow models used in the design of hydraulic works. Knowledge of the rainfall pattern is essential for hydraulic structures to be dimensioned so as to avoid flood-related accidents in urban areas. In this context, the objective of this work was to generate rainfall intensity curves by the alternating Sustentare | v. 2 | n. 2 | ago/dez 2018 | p. 2 blocks method, using the IDF (intensity-duration-frequency) relations adjusted for some localities of Minas Gerais. The IDF relations were obtained using the technique of disaggregation of the annual maximum maximum precipitations obtained in the Hidroweb rainfall database. Subsequently, the frequency analysis of intense rains was carried out, using the Gumbel distribution, in order to obtain the probabilities of extreme events associated to different return periods. Finally, using the alternating blocks method, the design logs for the advanced, centralized and delayed patterns were generated. For all the rainfall stations used in this study, a satisfactory adjustment of the IDF ratio was obtained, demonstrating reliability of its use in the generation of project hybrids. The generated rainfall intensity curves presented similar patterns, with a standard deviation of 0.37 mm with one of the amplitude between the largest and the smallest precipitated maximum leaf (1.11 mm), demonstrating that the region evaluated can be considered hydrologically homogeneous. For the Alfenas station, the largest precipitated blade (5.79 mm) was observed, while for the Pouso Alegre station it was the one with the smallest precipitated blade (4.68 mm).