بررسی کارایی مدل RHEM در برآورد فرسایش (مطالعه موردی: حوزه آبخیز سنگانه- خراسان رضوی)

Computer simulation models are increasingly popular for predicting soil loss to quantify the processes of detachment, transport and deposition of eroded soils. To assess the effects of different management on soil erosion, selecting the best models and their validation a positive step is considered. In this research the Rangeland Hydrology and Erosion Model (RHEM) was evaluated by using soil erosion measuring plots and recorded observed rain in Sangane research station, Khorasan razavi province, Iran. The model was run and the predicted runoff and sediment yield values were compared with measured runoff and sediment yield values. Then sensitivity analysis and calibration were done on sensitive parameters and model was run with calibrated parameters. In the calibration period, the model efficiency (ENS) values and the coefficient of determination (r2) were 0.92 and 0.95 for sediment, and 0.60 and 0.70 for runoff, respectively. In validation period, the (ENS) values and (r2) values were 0.70 and 0.84 for sediment and 0.11 and 0.65 for runoff, respectively. Our research indicated that the results of model were acceptable for sediment and could be used with reasonable confidence for soil loss quantification in the Sangane watershed.