Morphometric Assessment of the Bhadra Watershed Using Remote Sensing and GIS Techniques

Abstract

Morphometric analysis provides a quantitative basis for understanding watershed hydrology, terrain conditions and drainage development, and it supports planning for soil and water conservation. The present study assessed the morphometric characteristics of the Bhadra Watershed, a major sub-basin of the Tungabhadra River Basin in Karnataka, India, using Geographic Information System (GIS) techniques and Shuttle Radar Topography Mission Digital Elevation Model (SRTM-DEM) data with a spatial resolution of 30 m. The watershed was delineated in ArcGIS 10.8.2, and linear, areal and relief morphometric parameters were computed using standard methods. The Bhadra Watershed covers an area of 3422.01 km² and has a perimeter of 571.25 km and a basin length of 142.429 km. The drainage network was identified as fourth order and exhibited a dendritic drainage pattern, with 130 stream segments. The low drainage density (0.006 km/km²), stream frequency (0.038) and drainage texture (0.228) indicate a sparse drainage network, favourable infiltration conditions and reduced surface runoff. Areal parameters, including circularity ratio (0.132), elongation ratio (0.462), form factor (0.169), compactness coefficient (2.754) and shape factor (5.928), indicate that the watershed is highly elongated, with longer runoff travel time and lower peak discharge. Relief parameters showed a basin relief of 1368 m, relief ratio of 1.368, relative relief of 0.010 and ruggedness number of 0.008, reflecting considerable topographic variation with moderate erosion potential in steeper areas. The findings indicate that GIS-based morphometric assessment is useful for characterising the Bhadra Watershed and can support watershed planning, groundwater recharge assessment, soil conservation and sustainable water resource management within the Tungabhadra River Basin.