Application of WEPP model for runoff and sediment yield simulation from ungauged watershed in Shivalik foot-hills

Abstract The WEPP watershed model was applied for simulation of storm-wise runoff and sediment yield from two forest watersheds (WS-I and WS-II) having an area of 1.85 and 21.3 ha, respectively, situated in Shivalik foot-hills of North-West, India. The WS-I was divided into 29 hillslopes and 18 channels, while WS-II was divided into 35 hillslopes and 25 channels. CLIGEN software was used to create the climate file, which was based on the observed meteorological data. The soil, slope, and land-use management files were created for each hillslope and channel. The model was calibrated on WS-I and then applied to WS-II to ascertain whether the model must be calibrated every time it is applied to a new watershed in the region. The WEPP model was calibrated and validated by using the hydrological data of 22 storms (1982–2004) for WS-I and 13 storms (2001–4) for WS-II. The statistics showed that calibrated model for WS-I, simulated storm-wise runoff, and sediment yield for WS-II with advisable precision as substantiated by the lower values of RMSE (5.43 mm and 0.31 Mg/ha) and average error (2.09 mm and 0.09 Mg/ha) and high values of correlation coefficient (0.93 and 0.86) and model efficiency (83.90% and 69.50%). It is evident from this study that once the WEPP model has been calibrated on a representative watershed, it can be effectively applied to uncalibrated/ungauged watersheds in Shivalik foot-hills for watersheds with similar characteristics.