Assessment of the role of remote sensing techniques in monitoring shoreline changes: a case study of the Kerala coast

Abstract

The narrow stretch of Kerala coast in the south-western part of India shows dynamic changes in shoreline assuming a critical nature, which called for identification of causative factors. An attempt is made here to evaluate the use of LANDSAT imagery and air photographs in assessing and monitoring shoreline changes, using the Kerala coast as a case study, under the end-to-end experiments of the National Natural Resources Management System (NNRMS). Geological and terrain remote sensing based on lithological, structural and geomorphic analysis coupled with available data and field studies have revealed that the overall configuration of the coastline is controlled by both NNW-SSE and ENE-WSW trending lineaments, which are found to be neotectonically active. The differential movements along coastal segments have contributed to the compound nature of the coast. This aided by slope morphometry of the foreshore is found to cause variation in erosion/accretion in different stretches with varying intensity. The role of mud banks as a special causative factor is also stressed. This end-to-end experiment on the application of remote-sensing techniques for monitoring spatial changes in coastline, in particular to the study area, has shown that vulnerable areas could be identified using the spatial resolution of the present LANDSAT system. However, with improved spatial resolution, as available in the airborne MSS imagery, sequential aerial photography could be a semi-operational tool in user applications in contrast to the low resolution of the present LANDSAT system.