عنوان مقاله [English]
Rapid soil erosion is an undesirable phenomenon that reduces soil fertility and water resources capacity and causes water pollution. Investigators have suggested variety of models for prediction of runoff and erosion from which EUROSEM is a distributed single event model that can predict erosion risk from a hydrologic wathershed with respect to space and time. Due to spatial and temporal variations of rainfall magnitude and intensity, soil physical characteristics and topography of watershed area, consideration of these required variables can not be ignored. In this study, the impact of slope and unevenness density of a micro-catchment with heavy clay loam soil texture on runoff and erosion was evaluated using EUROSEM. In the first series, the experiments were performed for three unevennesses with three different densities and three replications in the direction of slopes of 5, 10 and 20 percent. In the second series, the experiments were performed with the same densities and slopes, but in the opposite direction of slopes. Totally, seventy seven tests including witnesses were accomplished. The results showed that density of unevennesses were effective to reduce runoff and erosion, especially when they were set up in the opposite direction of slopes, by 54 percent and erosion by 56 percent. The EUROSEM evaluation also showed that the model was able to assess all hydrograph parameters with regression coefficients (R2) more than 97 percent at the level of 95 percent and RMSE less than 4 percent successfully. Modle also is able to predict some of sedigraph parameters such as time to start sediment, time to peak of sediment and mass flow of sediment with regression coefficients (R2) more than 97 percent at the level of 95 percent and RMSE less than 0.289 percent successfully, but time to peak sediment was not successfully predicted, due to low R2 = 25 percent and high RMSE = 7.56.