Runoff and sediment yield modeling from a small agricultural watershed in India using the WEPP model Ashish Pandey a, * , V.M. Chowdary b , B.C. Mal c , M. Billib d a Department of Water Resources Development and Management, IIT, Roorkee 247 667, India b CSEAS, Kyoto University, Japan c Department of Agricultural and Food Engineering, IIT, Kharagpur 721 302, India d Institute of Water Resources Management, Hydrology and Agricultural Hydraulic Engineering, University of Hannover, Germany Received 30 July 2006; received in revised form 1 October 2007; accepted 2 October 2007 KEYWORDS GIS; Hydrological modeling; Remote sensing; Watershed; WEPP model Summary 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, run- off 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 (R 2 ) (0.86–0.91), Nash–Sutcliffe simulation model efficiency (0.85–0.95), and percent deviation values (7.90–15.15) indi- cate 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 determi- nation (R 2 ) (0.81–0.95), Nash–Sutcliffe simulation model efficiency (0.78–0.92) and per- cent deviation values (4.43–19.30) for sediment yield indicate that the WEPP model can be successfully used in the upper Damodar Valley, India. ª 2007 Elsevier B.V. All rights reserved. Introduction Reliable prediction of the quantity and rate of runoff and sediment from land surface into streams and rivers is diffi- cult, expensive and time consuming. In India, an estimated 175 Mha of land constituting about 53% of the total geo- graphical area suffers from deleterious effect of soil erosion and other forms of land degradation (Reddy, 1999). Active 0022-1694/$ - see front matter ª 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.jhydrol.2007.10.010 * Corresponding author. Tel.: +91 1332 285872; fax: +91 1332 271073. E-mail addresses: ashish_nerist@yahoo.co.in, ashisfwt@iitr. ernet.in (A. Pandey), chowdary_isro@yahoo.com (V.M. Chowdary), bmal@agfe.iitkgp.ernet.in (B.C. Mal), billib@iww.uni-hannover.de (M. Billib). Journal of Hydrology (2008) 348, 305– 319 available at www.sciencedirect.com journal homepage: www.elsevier.com/locate/jhydrol