A shoreline change analysis along the coast between Kanyakumari and Tuticorin, India, using digital shoreline analysis system

Abstract

The shoreline is one of the rapidly changing landforms in coastal areas. They are the key element in coastal GIS and provide the most information on coastal land form dynamics. Therefore, accurate detection and frequent monitoring of shorelines is very essential to understand the coastal processes and dynamics of various coastal features. The present study is to investigate the shoreline changes along the coast between Kanyakumari and Tuticorin of south India (where hydrodynamic and morphologic changes occur continuously after the December 2004 tsunami) by using Digital Shoreline Analysis System (DSAS), an extension of ArcGIS. Multidate IRS and Landsat Satellite data (1999, 2001, 2003, 2005, 2007, and 2009) are used to extract the shorelines. The data is processed by using the ERDAS IMAGINE 9.1 software and analyzed by ArcGIS 9.2 workstation. The rates of shoreline changes are estimated by three statistical methods, namely, End Point Rate (EPR), Linear Regression Rate (LRR), and Least Median of Squares (LMS) by using DSAS. The study reveals that most of the study area has undergoing erosion. Both natural and anthropogenic processes along the coast modify the shoreline configuration and control the erosion and accretion of the coastal zones. The coastal zones along the estuary have experienced accretion due to the littoral processes. The zones with headlands have more eroded than other zones along the study area. The study also shows that the coastal zones where sand is mined have relatively more rate of erosion than that of the other zones. Improper and unsustainable sand mining may also lead to severe erosion problem along this area. The shoreline change rates are altered by various geological processes along the coast. Thus, the present study implies that proper beach filling and nourishment projects should be made in the study area to save from hazards. It also indicates the advantage and suitability of DSAS to assess the shoreline changes compared with the traditional manual shoreline change analysis and promising its applications for coastal zone management in other regions.