Evaluation of the EUROSEM model with single event data on Steeplands in the Three Gorges Reservoir Areas, China

Because of the construction of the Three Gorges Dam in China, many farmers in reservoir areas will resettle in surrounding mountain areas and cultivate steeply sloping lands. Hence, a tool is needed to assess the risk of soil erosion, predict runoff and erosion rates, and design and evaluate soil protection strategies in this area. The European Soil Erosion Model (EUROSEM), a process-based model simulating erosion on an event basis for fields and small catchments, was tested using data from rainfall simulation experiments on steeplands (slopes≥47%) in the Three Gorges Reservoir areas. Simulations were carried out on plots representing four management treatments: uncultivated land, contoured-cultivated land, contoured-cultivated land with hedgerows and contoured-cultivated land with hedgerows + fertilizer. Results showed that, in most cases, EUROSEM predicted runoff reasonably well. Simulation of the timing and rate of soil loss was unsatisfactorily, mainly because of poor estimation of sediment concentration in runoff, but total soil loss during a rainfall event was adequately predicted in most cases. Differences between measured and simulated values in total runoff and total soil loss were less than 3 mm and less than 120 kg ha−1, respectively, except for a single validation test on the contoured-cultivated treatment. This model is capable of differentiating impacts of land use changes and soil protection measures on steeplands in this area.