Artificial rainfall simulator is a very effective experimental device for studying the impacts of rainfall on infiltration

runoff

soil erosion

and sediment transport

because it can simulate natural rainfall without temporal and spatial limitations.A trough rainfall simulator was designed

which could simulate similar rainfall characteristics to those of natural rainfall.To provide a guide for users to make and use the apparatus

an experiment for calibrating simulator's rainfall intensity was conducted with single nozzle raining and multiple nozzles together at the height of 2.5 m.Results show that the rainfall intensity simulated by this simulator ranges from 11.3 to 132.5 mm/h.Single nozzle raining has a rectangular rainfall area of 5.4 m2

2 m width parallel to simulator and 2.7 m length perpendicular to simulator.Combined multiple nozzles are needed to generate a uniform rainfall intensity distribution.The combining experiment indicates that the optimal distance between two close nozzles is 1.1 m in the swing direction and 1.5~1.6 m in the perpendicular swing direction.The homogeneity coefficient of simulated rainfall intensity is more than 0.89.One trough rainfall simulator is composed of five nozzles and the distance between the two close nozzles is 1.1 m

which direction is called swing direction.According to the experimental area

users can choose the number of nozzles and simulators themselves and the suggested distance between two simulators is from 1.5 to 1.6 m.