Hydrological Modeling of Bhagirathi River Basin Up to Tehri Dam Using ArcSWAT

Abstract

The river Bhagirathi comes from Gaumukh Glacier and merges with Alaknanda before flowing for about 193km to form River Ganga at Devprayag. Due to the intensity of the flooding in this area, the Bhagirathi watershed basin, one of the most significant basins in Northern India, necessitates aggressive water resource management. There are no significant studies available for Bhagirathi basin of northern India. The study is an attempt to utilize the Soil and Water Assessment Tool to simulate streamflow in this basin via a watershed model called ArcSWAT. The outcomes of this study will be helpful in water resource management and mitigation of flood in this basin. This study includes Sequential Uncertainty Fitting technique, which was applied for analysis of the data and allowed for calibration and global sensitivity using the SWAT-Calibration and Uncertainty Program (SWAT-CUP). The feasibility of this model was reported on the basis of R² and NSE (Nash Sutcliffe efficiency). Together, these variables show how well the SWAT model's calibration-uncertainty analysis has been done. After the calibration and validation, a global sensitivity analysis was conducted to identify the parameters in the basin that were the most sensitive. Results shows the GW_DELAY (Ground Water Delay) was found most sensitive parameter. The results of this study can be utilised efficaciously in the Bhagirathi basin to mitigate floods, manage droughts, water resource management, and prepare for hydraulic structures, according to the statistical parameters of this study.