Morphometric analysis and prioritization of sub-watersheds in the Gosthani River Basin of southern India using PCA-WSM and geospatial techniques

In the present study, morphometric analysis of the Gosthani River Basin (GRB) was performed utilizing the Principal Component Analysis-Weighted Sum (PCA-WSM) approach and geospatial techniques. ASTER GDEM (Advanced Spaceborne Thermal Emission and Reflection Radiometer Global DEM) was utilized. The GRB's 25 sub-watersheds (SWDs) were prioritized based on the basin's erosive properties, employing nine morphometric factors such as bifurcation ratio (Rb), drainage density (Dd), stream frequency (Fs), drainage texture (Dt), shape factor (Bs), elongation ratio (Re), form factor (Rf), circulatory ratio (Rc), and length of overland flow (Lo). These parameters were chosen because they are the most crucial factors of erosion risk. Weights were obtained by using PCA to compute the compound factor and ranking of SWDs. The values of Rb (4.03) and Dd (1.84 km/km2) show that geology and structural control have a moderate impact. The likelihood of significant erosion and material movement is indicated by the basin relief (r = 1,428 m), relative relief (RLr = 0.54), and ruggedness number (Rn = 2.63). The correlation matrix of geomorphic parameters reveals that more than 75% of the variables have strong correlations between their components.