Morphometric analysis of the Kadalundi River basin, North Kerala, India, using GIS and Remote Sensing Techniques

ABSTRACT Morphometric analysis was carried out to evaluate the quantitative characteristics of the Kadalundi River Basin (KRB), a west-flowing river system in North Kerala. Linear, areal, and relief aspects were computed using ArcGIS 10.8, including parameters such as stream order (Nu), stream length (Lu), bifurcation ratio (Rb), stream length ratio (Rl), drainage density (Dd), stream frequency (Fs), form factor (Ff), elongation ratio (Re), circularity ratio (Rc), shape index (Sw), basin relief (R), ruggedness number (Rn), relief ratio (Rr), dissection index (DI), and Melton ruggedness number (MRn). KRB, a sixth-order river with 22 fourth-order sub-basins (SB1–SB22) draining 1257.37 km², displays a dendritic drainage pattern. Key morphometric values include perimeter (227 km), Rb (22.10), basin length (65 km), Lu (1157.01 km), Fs (1.44), T (1.31), Lg (0.55), C (1.10), Ff (0.30), Rc (0.31), Re (0.62), and Sw (3.33). The mean drainage density is 0.91 km/km², indicating very coarse drainage texture and a mature geomorphic stage. Relief parameters show R = 1320 m, Rr = 0.02, Rn = 1.20, DI = 0.99, and Rg = 0.20. The mean Rl is 9.43, with variations (0.97–8.09) reflecting slope and topographic control. Rho values range from 0.13 to 0.92, with higher values (≥0.50) in sub-basins such as SB4 (ρ = 0.92), suggesting enhanced hydrologic storage and erosion attenuation. The basin exhibits an S-shaped hypsometric curve, consistent with a mature landscape. These morphometric insights reveal basin hydrological behaviour, sub-basin variability, and structural influences, providing a foundation for watershed management.