Rainfall simulator for field runoff studies

Rain simulators (RSs) are used in soil crusting and soil erosion laboratory and field studies. The energy flux produced by RSs is usually high in respect to the intensity of the application. The high energy flux applied on the soil surface by these RSs becomes a crucial disadvantage when low intensity rainfall is considered. Moreover, crust formation under natural field conditions is very different from crusting in disturbed soil samples. The main purpose of this study was the design and the construction of a portable RS to be used in the field for simulating rainfalls that induce soil crusting and thus lead to the generation of runoff and eventually soil erosion. A high accuracy portable RS for field rainfall simulations was designed and built. The D ₅₀ of the drops is 1.5mm with a ground hitting velocity that nearly matches the theoretical terminal velocity without the necessity of a tower (Barros et al., 2008). The energy flux of the simulated rain is 76% of the energy flux expected for a natural rainfall of the same intensity. The spatial distribution of water is homogenous for a wide range of rain intensities. This RS can be a powerful tool for field infiltration, soil crusting and soil erosion field trials.