The generation of surface runoff in laboratory conditions using two portable rainfall simulators – an experimental study

The use of laboratory methods in soil water erosion studies and rainfall simulation experiments has recently been considered more important because of the many advantages in controlling rainfall-runoff processes and sediment transport. In a laboratory study, rainfall simulation experiments (one alone and two identical rainfall simulators connected in a series) were focused on an analysis of the impact of the size of the irrigated area on the temporal distribution and volume of the surface runoff and the amount of eroded soil material. The experiments were conducted on a disturbed soil sample exposed to quasi-continuous 60-minute simulated rainfall events with an intensity of 2.7 mm min -1 . The two experiments were carried out on slopes of different lengths of 0.25 m (irrigated area: 0.0625 m 2 ) and 0.5 m (irrigated area: 0.125 m 2 ). The results showed the effects of the size of the irrigated area on surface runoff generation and changes in the soil structure, sediment concentration, and amount of soil loss. Knowledge of the rate of changes in the volume of the surface runoff and soil loss with respect to the size of the irrigated area in the laboratory conditions and subsequent generalization of the results provides essential information, which is irreplaceable for the preparation of field measurements and obtaining essential calibration and validation data for erosion and rainfall-runoff modelling.