Design and operation of a rainfall simulator for field studies of runoff and soil erosion

摘要

The present paper describes the design, construction, calibration and operation of a spray rainfall simulator, and the plot equipment for field studies of soil erosion processes generating solutes and sediments subsequently transported by runoff. Selected rainfall intensities of 48 and 58 mmh−1 are representative of storm events of 15 minutes duration and of the maximum intensity encountered in the middle section of the Ebro valley. The drop size distribution of the simulated rainfall is close to that recomended by BUBENZER (1979). For D50, fall velocities obtained by operating pressures of 29.4 and 58.8 kPa represent between 85 and 97% (rainfall of 48 mmh−1) and between 86 and 98% (rainfall of 58 mmh−1) of their terminal velocity. According to the sprinkling height, average kinetic values are 13.10 Jm−2mm−1 for rainfall of 48 mmh−1, and 13.00 Jm−2mm−1 for rainfall of 58 mmh−1. Application of simulated rainfall for 15 minutes proved sufficient to obtain directly applicable data.