Terrain analysis and hydrogeomorphic investigation of the Sita-Swarna river basin, Udupi, SW India: Insights from remote sensing methods

Hydrogeomorphic characteristics of the Sita-Swarna river basin, Western Ghats, India, are investigated to understand the influence of lithology, structure and geological control on the channel morphology. For preliminary investigation, remote sensing, geomorphic and morphometric analysis was carried out, producing slope, aspect and lineament maps from a 30 m resolution Digital Elevation Model (DEM) with the help of GIS. Remote sensing analysis inferred a steep south-to-southwest slope with dominant lineaments trending NW and ENE to E in the middle reaches of the Sita-Swarna river basin. These lineaments are deduced to have possibly been instigated by faults, shear zones, dyke ridges, or subsurface structures that influence the surficial topography. Upland and pediment geomorphic zone were identified, inferring Western Ghats Escarpment (WGE) and gently coastward W-sloping dissected pediment surface. A comprehensive morphometric analysis is performed using various linear, areal, and relief parameters for basin characterization. The linear parameters infer that the basin is structurally controlled and shows moderate to high permeability and flood susceptible areas downstream. The calculated morphometric parameters for basin characterization reveals that the Sita-Swarna river basin is at the mature stage of development and highly asymmetrical with the westward tilt, which indicates a possible influence of paleo tectonism. Rapid runoff is observed due to the steep escarpment leading to less infiltration and flash flood possibility during heavy rainfall. The present study mainly establishes the potential application of remote sensing methods to quantify the hydrogeological aspects, basin morphometry and landscape evaluation in the tropical climatic zone.