Landscape Evolution in Parts of Varnanapuram Drainage Basin, Kerala-a Hypsometric Approach

Morphometric and hypsometric parameters provide significant indicators for deciphering the erosional processes, and influence of geologic and tectonic factors on landscape development. The present study covers 22 fourth order Sub-Basins of the Vamanapuram drainage basin of Kerala Based on hypsometric analysis the Sub-Basins are grouped into three sets representing old, mature and late mature stage. It is possible to identify two erosional processes, namely, fluvial and diffusive, from hypsometry of the Sub-Basins. Diffusive processes dominate Sub-Basins adjoining the Western Ghats, particularly those draining the flank of the Ghats, while fluvial processes dominate the sub basins in the midlands and foothills. However there are some Sub-Basins in the midland where diffusive processes are found to be active Relative up lift of the Sub-Basins indicates Fault-Related movement, and possible reactivisation of old fault lines or lineaments.