Hydrological Modeling of Gandak River Basin Watershed Using the SWAT Model

Abstract

Since the entire life system depends on land and water, these two natural resources are extremely vital. Therefore, for maximum exploitation, effective management of it is necessary. The management of land and water resources, as well as the hydrologic behaviour of watersheds, can be effectively achieved by hydrological modeling. Several morphological (DEM), thematic, and meteorological (precipitation, temperature, wind speed, relative humidity, and solar radiation) data were used to feed the model. The conceptual and semi-distributed SWAT model is implemented to the 699.19 km2 watershed in the present research. Utilizing the SWAT Model with GIS and remote sensing assistance, sensitivity analysis of the model has been performed in order to identify the important watershed parameters. The SWAT model was calibrated from 2005–2014 (warm up period: 2002–2005); and validated from 2015-2022. The coefficient of determination (R2) and Nash Sutcliffe efficiency (NSE) ,for calibration and validation are 0.975, 0.985 and 0.98, 0.9901, respectively.