Determination of runoff and sediment yield from a small watershed in sub-humid subtropics using the HSPF model

The Hydrologic Simulation Programme-Fortran (HSPF), a hydrologic and water quality computer model, was employed for simulating runoff and sediment yield during the monsoon months (June-October) from a small watershed situated in a subhumid subtropical region of India. The model was calibrated using measured runoff and sediment yield data for the monsoon months of 1996 and was validated for the monsoon months of 2000 and 2001. During the calibration period, daily-calibrated runoff had a Nash-Sutcliffe efficiency (ENS) value of 0.68 and during the validation period it ranged from 0.44 to 0-67. For daily sediment yield ENS was 0.71 for the calibration period and it ranged from 0.68 to 0.90 for the validation period. Sensitivity analysis was performed to assess the impact of important watershed characteristics. The model parameters obtained in this study could serve as reference values for model application in similar climatic regions, with practical implications in watershed planning and management and designing best management practices. Copyright (c) 2007 John Wiley & Sons, Ltd.