Statistical analysis of maximum precipitation intensity behaviors from microregions in south Bahia, Brazil

Abstract

Our understanding of maximum intensity of precipitation in a given place is of great technical interest for hydraulic works projects such as the dimensioning of micro- and macro-drainage systems for rainwater in urban, rural and road areas. In this context, the present study aimed to compare (statistically, using the Student's t-test at a 5% significance threshold) the values of maximum precipitation intensity between the three micro-regions in the southern area of Bahia, Brazil. We used precipitation times of 10, 30, 60, 120 and 1,440 minutes and return periods of 2, 10, 50 and 100 years. For each of the 20 scenarios that resulted from the crossing of the precipitation duration and return period values, the precipitation intensity values of the 70 municipalities in the mesoregion were calculated and the micro-regional averages were compared in order to verify the occurrence of heterogeneous precipitation intensity behavior. It was found that the three microregions do not have large discrepancies, and only occasional disparities were identified in certain scenarios. One disparity was the greater susceptibility of the Porto Seguro microregion to short-term rainfall.