Review of the high intensity rainfall zones of Brazil

ABSTRACT

The use of rainfall intensity-duration-frequency relationships (IDF relationship) is very important for the development of Engineering projects. However, the availability of this information is limited in Brazil. Due to this, the engineer Taborga Torrico, in 1974, proposed eight regions with homogeneous climatic conditions (named "isozonas" in Portuguese) with similar rainfall behavior, suggesting parameters for heavy rainfall estimative in ungagged places within them. Due to the absence of better information, the results presented in Torrico study are still used in several Engineering projects. This paper presents a reanalysis of these regions and parameters based on recent IDF's information. The results show that, in general, the proposed regions are still valid. However, in several places, the original values present large differences compared to the updated data, such as in Southeastern Brazil, where this paper results shows an intensification of smaller-duration rainfall, or the Midwest Brazil, where results indicate an opposite situation. In this light, this paper presents updated values for intense rainfall estimation in ungagged sites of Brazil.

Keywords:
heavy rainfall zones; isozonas; Brazil