HYDROLOGICAL MODELING OF WONOGIRI CATCHMENT USING REMOTE SENSING AND GIS

Abstract

In this study, Geographical Information System (GIS), Remote Sensing (RS) and the SWAT (Soil and Water Assessment Tool) model are used for hydrological modeling of the Wonogiri catchment for simulation of runoff and evaluation of impact of land cover change on the surface runoff. The SWAT model was calibrated with the observed daily discharge measured at the watershed outlet for the year 1992-1999. After calibration the coefficient of determination (R2), Relative Error (RE %) and Nash-Sutcliffe coefficient (E) were obtained as 0.913, 17.971 and 0.868 respectively. After calibration, the model was used for prediction of runoff. The SWAT model was validated with the observed daily discharge measured at the watershed outlet for the year 1997-1999. For the model validation, the coefficient of determination (R2), Relative Error (RE %) in and Nash-Sutcliffe coefficient (E) was obtained 0.908, 17.707 and 0.861 respectively. The SWAT model simulation results showed that the amount of runoff was increased when land use/Land cover was changed to Urban, Forest, Orchard and Paddy field. Change to urban area has resulted in increasing the amount of the runoff by 1.95%. For forest, orchard and paddy fields, impact on increasing the amount of the runoff by 1.13%, 0.64% and 1.12% respectively.