Quantification of drainage networks in relation to geomorphology, lithology, climate, and tectonics gives important evidence of an area’s hydro-geomorphic, denudation characteristics, and drainage development. The current research used the Shuttle Radar Topographic Mission (SRTM) DEM to investigate drainage morphometry and its impact upon the environment, as well as hydrological analysis of the Gandak river basin, which is a prominent tributary of the River Ganga in India. The morphometric characteristics of watersheds have been evaluated using avant-garde methods like those developed by Horton and Strahler. Their findings demonstrate that techniques for geographic information systems and remote sensing are more effective for computing and analysing morphometric parameters. Using the Arc GIS 10.5 programme, 17 morphometric parameters were determined. These parameters reflect the dendritic type of drainage pattern of Gandak watershed. Specifically, these watershed has a porous subsurface; hence, runoff is comparatively modest, as seen by the low drainage density, infiltration rate, and frequency of streams. The Gandak basin’s low drainage density and coarse drainage pattern suggested an open opportunity for artificial recharge structures. The current morphological-based prioritisation is also supported by geological field verification. As a result, adequate soil erosion management techniques are required in this basin to protect the land from future erosion. This research will aid in the efficient use of water resources and the long-term development of the Gandak River basin.