Erosivity Index and Characteristics of Erosive Rainfall from the Far Western Region of Santa Catarina, Brazil

Abstract

The objective of this study was to determine the erosivity index and to characterize the erosive rainfalls with respect to the far western region of Santa Catarina. Four meteorological stations were used to determine the rainfall erosivity based on the index of the product of the maximum rain intensity during a 3 min period and the kinetic energy of the rain (EI3), and the equations were adjusted to estimate the EI3 value from the rainfall coefficient. Erosive rainfalls were classified, according to the pattern of temporal distribution, as Advanced, Intermediate, and Late rainfall pattern. The erosive rainfalls represent, on average, 83–88% of the annual precipitation, and the value of EI3 varies from 6,72 to 1,478 MJ mm ha−1 h−1 year−1. The adjusted equations can be used to estimate the rainfall erosivity in places with only pluviometric data. Erosive rainfalls presented an average distribution of 51, 31, and 18%, respectively, of the Advanced, Intermediate, and Late patterns. The maximum rainfall intensity of 3 min with 2% of frequency ranged from 21.8 to 33.6 mm h−1. For larger frequency, no significant variation was observed between the time distribution patterns.