Comparative Geomorphometric Approach to Understand the Hydrological Behaviour and Identification of the Erosion Prone Areas of a Coastal Watershed Using RS and GIS Tools

Abstract Assessment of the geomorphometric parameters using RS and GIS tools assumes an imperative part in routing the runoff and the remaining hydrological processes. The current study demonstrates a geospatial model based on geomorphometric parameters for the categorization of surface runoff and identification of the erosion-prone areas within the watershed. The 4th order Kuttiyadi river is dominated by a dendritic to semi-dendritic drainage pattern in the subwatersheds. The linear aspect of subwatersheds indicates the subwatersheds have a structurally permeable surface and subsurface materials with uniform lithology. The aerial and relief aspects of the subwatersheds shows fine drainage texture, gentle slopes, delayed peak flow, flatter hydrograph, and large time of concentration which indicates subwatersheds are quite capable to manage flash floods during storm events. The estimated values of surface runoff and sediment production rate are range from 2.13-32.88 km2-cm/km2 and 0.0004-0.017 Ha-m/100km2/year respectively and suggest that SW1 will generate more surface runoff and prone to soil erosion followed by SW2 while compare to the other subwatersheds. As a result of this paper, reliable assessment of peak flooding and relevant basic knowledge will be provided to decision-makers and policymakers responsible for establishing suitable policies and sustainable land use practices for the watershed.