Comparison of rainfall kinetic energy–intensity relationships for Eastern Ghats Highland region of India

Abstract

Kinetic energy and intensity of rainfall are commonly used factors to predict soil erosion by water. The difficulty in measuring these parameters triggers the scientific community to use the kinetic energy–intensity relationship to compute soil erosion. Six kinetic energy–intensity relationships (three exponential, one linear, one logarithmic and one power law) were used to compute and compare rainfall erosivity of Eastern Ghats Highland region of India. The result showed that when the rainfall intensity was\6 mm h-1, there was a significant difference among the kinetic energy values computed using Brown and Foster, McGregor and Hudson relationships; however, no significant difference was observed for the values computed with van Dijk and Wischmeier and Smith. On the other hand, there was no significant difference in kinetic energy values computed with the different equations for rainfall intensity greater than 30 mm h-1. Highest and lowest rainfall erosivity was computed for Meshesha (6633.0 MJ ha-1 mm h-1 y-1) and Hudson (5503.2 MJ ha-1 mm h-1 y-1) equations, respectively. On an average, annual rainfall erosivity value was observed to be 23.4% lower when computed using I60 than that of I30. Therefore, use of I60 in place of I30 for the study area cannot be suggested. Instead of that, proper calculation of I30 is more important than choosing right kinetic energy–intensity relationship equation.