Rain microstructure and erosivity relationships under pressurized rainfall simulator

Abstract

Rain simulators have been used extensively in order to assess the interaction between rainfall and land surface. The main objective of a rain simulator is to produce rain with characteristics similar to natural rainfall at a certain geographical location. This paper investigates the microstructural characteristics of rainfall generated by a pressurized simulation system and their impact on rainfall erosivity in comparison with natural rainfall for different environments. The simulated raindrop characteristics have been measured using two piezoelectric transducers to investigate the rainfall kinetic energy and drop size distribution. The pressurized simulation system was able to generate rain with different intensities and the relationship between the pressure and rainfall intensity was statistically significant. On the other hand, the time-based rainfall kinetic energy was increasing linearly with rainfall intensity. The pressurized rain simulator showed low volume-based kinetic energy (KE<inf>c</inf>) and the trend was different from that observed under natural rainfall. The average percentage of small raindrops (<2 mm) was more than 98%, and the average median drop size was 1.4 mm. © 2015 American Society of Civil Engineers.