Comparing the rate of runoff and sediment derived from natural rainfalls and rainfall simulator

This Research was done on rangelands in the foothills of the mountain in Asbforushan Bozghoush village of Sarab city. Runoff and sediment caused by natural events based on the standard scale plot of the results of the runoff and sediment generated by the simulator was built to evaluate and to compare. For this purpose, the three slope treatment 5, 9 and 25% of the standard plot (length 22/1 m, 1/83 meters wide and spaced 2.1 m) and were created by the north aspect . In this study, we tried to make the slope and vegetation effects on runoff and sediment production in rainfall and runoff simulation using artificial rainfall simulator. For this purpose, to simulatiy natural rainfall, tried to made and stablished natural rainfall parameters and the results are compared together. 4 of 33 rainfall precipitation occurred during the study, showed the maximum amount of sediment in the study period, 25% of the amount of 101 gr/m2 slope and rainfall intensity of 2 mm/min (2/81 mm in 14 minutes). The results showed a significant effects of the slope and vegetation components on runoff and sediment in the study area. The maximum slope of 25% share had created in runoff and sediment production in the region. However, the slope of 5% that were both the vegetation and the removal of vegetation. the Effects of natural precipitation, runoff and sediment was not observed during rainfall Simulating. Analysis of variance for different values of the slope, presence or absence of vegetation and soil physical properties showed that there were no effects on runoff and sediment components which parameters slope, presence and absence of vegetation and silty soils on all components of runoff and sediment (ahead of the runoff, runoff, runoff coefficient, erosion or deposition of sediment load and concentration) were, too. Such that the threshold runoff on slopes of 25% and no vegetation was 2 minutes after the start of precipitation. However, the presence of vegetation on the slopes, ahead of the runoff, was 6 times more (12 minutes after the precipitation). However, in the slope of 5%, ahead of the runoff was observed during the study period. In fact the entire natural precipitation and precipitation of rainfall simulator, due to lack of soil and soil crust, there were not a trace of runoff and sediment.