Regional scale hydrologic modeling for prediction of water balance, analysis of trends in streamflow and variations in streamflow: The case study of the Ganga River basin

Study region: Ganga River basin. Study focus: The availability of freshwater has been recognized as a global issue, and the reliable evaluation and quantification of it within the basin is necessary to bolster the sustainable management of water. For this purpose a basin-scale SWAT model of the Ganga River basin has been developed. New hydrologic insights for the region: Model validation showed that simulated results were consistent with the observed data in reproducing the seasonal dynamics of surface water and suggest that the model is capable of reproducing the hydrological features of the basin including the snow melt. However, there are large variations in both temporal and spatial distribution of the hydrological components. Statistical methods have been used for detecting trends and critical changes in streamflow. It has been found that although the streamflow from the snow fed areas has increased, the stream flow in the lower reaches and the non-perennial tributaries have declined significantly. This decline can be attributed to both anthropogenic and exogenous changes. The study also establishes that there has been a substantial reduction in overall water resources availability with respect to Virgin. This information sets the yardstick to the restoration of the hydrological and environmental health of the basin and can lead to better management of water resources under scarcity.