Exploring and modelling the hydro-morphological landscape of a Himalayan basin: a geospatial study of Nandakini Basin in Uttarakhand, India

Abstract This study comprehensively examines the hydro-morphological, topo-hydrological, and physiographic features of the Nandakini catchment in the north-western Himalayas. In the absence of extensive hydrological data, employing morphometric parameters proves to be a crucial and efficient approach for delineating geological structures and assessing hydrodynamic activity in the river basin. Utilizing SRTM DEM, SOI toposheets, and GIS, the study identified twenty watersheds within the catchment, estimating its total area at 540.98 km2. The analysis revealed a 6th-order catchment with a primarily sub-dendritic to dendritic drainage pattern, susceptible to flooding and gully erosion from slow surface runoff. The elongated shape and compactness coefficient indicated delayed peak runoff. Coarse drainage texture and high relief ratio suggested increased vulnerability to erosion. Physiographic indices indicated a later youth stage of basin development, while topo-hydrological indices highlighted significant topographic and spatial variability in water availability, emphasizing erosion potential. This study provides valuable insights for developing sustainable catchment management plans and informing decision-making in water resources management for the Nandakini catchment.