Assessment of WEPP model applicability in Beijing mountainous area

Soil erosion is one of the global environmental problems at present. Accurate prediction and prevention of soil erosion has become a huge challenge. The development of WEPP model provides an important support for the prediction and assessment of soil erosion. To evaluate the applicability of WEPP model in Beijing mountainous area, we measured rainfall-runoff-sediment data during 2001-2006 at Yanqing field runoff plots of Beijing and applied them in model calibration and validation. We evaluated the applicability of WEPP model in the mountainous area of Beijing, which has important implications for soil erosion prediction in mountainous areas. Under cinnamon topsoil (0-10 cm) condition, the minimum cumulative error and Nash-Sutcliffe efficiency coefficient (E) were used to perform model calibration and validation. Results showed that the calibrated values of effective hydraulic conductivity, soil critical shear, and rill erodibility were 1.400 mm/h, 1.000 Pa and 0.010 s/m, respectively. For the validation, the WEPP model presented a higher simulated accuracy for runoff than for erosion yield according to E of 0.730 and 0.670. Correlation coefficients and path analysis of rainfall parameters indicated that 30-minute maximum rainfall intensity (I30) has the greatest impact on runoff and erosion yield, and subsequently on the precipitation. Duration of rainfall has no correlation with runoff and erosion yield, with little direct impact on them.