University of Tehran Press Journal of Ecohydrology 2423-6098 5 1 2018 03 21 Designing and construction of a portable rainfall simulator Designing and construction of a portable rainfall simulator 229 239 64837 10.22059/ije.2018.239387.695 FA Soheila Aghabeigi Amin Mahmood Arabkhedri Water & Soil Conservation Dep., SCWMRI Journal Article 2017 08 22 Rain simulation is one of the important methods for measuring hydrological and soil erosion processes. Rapid evaluation and high repeatability capabilities are the advantages of using the rainfall simulator. The weight of constructed simulator is approximately 20 kg, can simulate rainfall at 28 to 95 mm / h intensity on the plot area of one up to three square meters. The droplet diameter was measured using flour pellet method and stain method. Flour pellet method was selected due to higher determination factor, and then its results were applied to continue the study. The highest uniformity coefficient (96.6%) was obtained at the intensity of 8.3 cm/h and the lowest coefficient (90.6%) was obtained at 9.5 cm/h intensity, which is higher than the acceptable level. The average diameter of the droplets is from 0.97 mm at intensity of 2.8 cm/h to 1.22 mm at 7.1 cm/ h, which lies within the range of natural precipitation. Also, the range of velocity variations is from 3.58 to 4.21 m/s. According to the mentioned specifications, a suitable portable rainfall simulator was designed with acceptable accuracy for runoff, permeability, erosion and sedimentation studies in field. Rain simulation is one of the important methods for measuring hydrological and soil erosion processes. Rapid evaluation and high repeatability capabilities are the advantages of using the rainfall simulator. The weight of constructed simulator is approximately 20 kg, can simulate rainfall at 28 to 95 mm / h intensity on the plot area of one up to three square meters. The droplet diameter was measured using flour pellet method and stain method. Flour pellet method was selected due to higher determination factor, and then its results were applied to continue the study. The highest uniformity coefficient (96.6%) was obtained at the intensity of 8.3 cm/h and the lowest coefficient (90.6%) was obtained at 9.5 cm/h intensity, which is higher than the acceptable level. The average diameter of the droplets is from 0.97 mm at intensity of 2.8 cm/h to 1.22 mm at 7.1 cm/ h, which lies within the range of natural precipitation. Also, the range of velocity variations is from 3.58 to 4.21 m/s. According to the mentioned specifications, a suitable portable rainfall simulator was designed with acceptable accuracy for runoff, permeability, erosion and sedimentation studies in field. https://ije.ut.ac.ir/article_64837_7e087f0dfc8edbf193f926552c6817fd.pdf