Runoff and sediment yield modeling from a small agricultural watershed in India using the WEPP model

The WEPP (Water Erosion Prediction Project) watershed model was calibrated and validated for a small hilly watershed (Karso) of India. Sensitivity analysis of the model was carried out for the input parameters. The analysis shows that the sediment yield is highly sensitive to interrill erodibility and effective hydraulic conductivity, whereas, runoff is sensitive to effective hydraulic conductivity only. Initially, the model was calibrated using data from the 1996 monsoon season and subsequently its performance was evaluated by estimating the daily runoff and sediment yield using the monsoon season data of different years. Coefficient of determination (R2) (0.86–0.91), Nash–Sutcliffe simulation model efficiency (0.85–0.95), and percent deviation values (7.90–15.15) indicate accurate simulation of runoff from the watershed. Performance of the WEPP model for simulation of sediment yield was also evaluated. High value of coefficient of determination (R2) (0.81–0.95), Nash–Sutcliffe simulation model efficiency (0.78–0.92) and percent deviation values (4.43–19.30) for sediment yield indicate that the WEPP model can be successfully used in the upper Damodar Valley, India.