Performance of rangeland hydrology and erosion model for estimating sediment yield on rangeland's hill slopes in dry regions (A Case study: Shahid Noori watershed, Khorasan Razavy)

Soil erosion is undoubtedly one of the most important problems in natural areas and has a devastating impact on grassland ecosystems. The present study was conducted to assess the ability of Rangeland Hydrology and Erosion Model for estimating sediment yield on rangeland’s hill slopes in dry regions at Shahid Noori paired watershed of Kakhk. RHEM is a mathematical, distribution and physical model that is capable to simulate hydrological and erosional processes with climatic data and hill slope’s characteristics. Measuring of sediment yield performed on 18 erosion plots in both disturbed and undisturbed rangeland conditions. In order to implement the model, the parameters of climate, soil texture, slope length, slope steepness, canopy cover and ground cover were measured and entered into the model to estimate amount of runoff and sediment yield in each year. The analysis showed no significant difference between observed and estimated values at 5% level in both all erosion plots and the average of measured values of all three different aspects. The results indicate that the model is capable to determine the quantity effects of rangeland conservation practices in hydrological and soil erosion processes. Overall, the present study suggested good potential for application of the model in the same rangelands of dry regions.