Process for the Parameterization of a Soil Erosion Model Based on a Small Rainfall Simulator

Abstract

Soil erosion due to water is an extensive problem in many countries, especially accelerated erosion, where the natural rate has significantly increased in the most recent period. Its extent impacts on land management practices and is the main factor causing soil degradation. Rainfall simulators are very popular as a standard instrument to conduct research on topics such as soil erosion, infiltration or surface runoff. They are used in laboratory or field experiments in erosion studies to assess the impacts of changes in the tillage management with regard to the erodibility of soil. Results of the experiments can be used in the modelling of surface runoff and sediment transport by hydrological models. This study presents the results of experimental measurements of surface runoff made by an artificial rainfall on an experimental plot. The artificial rainfall was generated using a small rainfall simulator, which allows changes in rainfall intensity and duration. The object of this study was analysed after the surface runoff occurred and the weight of the soil particles was transported from the experimental plot. These results have been used to determine the soil input parameters for the physically-based EROSION-2D model and for the verification of the model parameters. The EROSION-2D model represents a physically and event-based approach for the prediction of soil loss and runoff. The model only requires eight soil input parameters. Some of those parameters can be easily obtained by classic and widely-used methods (soil analyses, terrain measurements, soil map evaluations), and other parameters can be determined from rainfall experiments which represent the main aim of the study. The rainfall intensity has been set at 5 mm/min with 20 minutes of simulated rain, and it corresponded to an intensity with a return period of 100 years. During the experiment a continuous course of the surface runoff and soil moisture was recorded. The results from the simulations were applied to simulate the soil erosion processes in the physically-based EROSION-2D model. For the parametrization of the model, artificial rainfall events were used with an intensity of 2.7 mm/min and rain durations of 12 and 13 minutes. The parametrization of such models represents a necessary and significant part of any scientific work. The experimental results show that outputs from the rainfall simulations can be reproduced successfully, and, based on the results, the process of determining the model's parameters can be successfully performed.