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Abstract:

Hypsometric analysis is a significant tool for assessing the influence of geologic and tectonic factors on topography and also to prioritize sub-watersheds based on soil erosion and runoff. To understand the type of erosive processes and relative age of land forms, hypsometric analysis is carried out for all the 15 sub-basins of Meenachil River Basin, a humid tropical river basin of the Western Ghats, Kerala. Hypsometric analysis was performed on SRTM DEM (90m resolution) to derive the hypsometric parameters and the curves for each sub- watershed as well as to entire basin using CalHypso an Add-on tool to Arc GIS 9.2 and the statistical data like hypsometric integral, skewness and kurtosis were also determined. Based on the shape of hypsometric curves and value of hypsometric parameters, the geomorphic stages of the sub watersheds were identified, and the erosion status of the watersheds was finally predicted based on the geomorphic stages. Among the 15 sub-watersheds, six sub-watersheds indicate the in-equilibrium stage as the Hypsometric Integral > 0.3. The analysis also revealed that the lithologic and structural differences between areas or recent minor uplifts for sub-watersheds SW4, SW5, SW8, SW11, SW12 and SW13. The pattern of the hypsometric curves of SW6, SW7, SW14 and SW15 suggested that the formation of alluvial deposits made the watershed favourable for groundwater re-charge.