Evaluation of coastal erosion and accretion processes along the southwest coast of Kanyakumari, Tamil Nadu using geospatial techniques

Abstract

The impact of coastal erosion has adversely affected the socioeconomic conditions of the coastal community worldwide. The coastal environment is experiencing a wide range of natural and anthropogenic pressure in India. This study was carried out along the southwest coast of Kanyakumari, South India using multitemporal Landsat satellite images from 1999 to 2011. The long-term coastal erosion and accretion rates have been calculated for the periods between 1999 and 2011, and the subsequent short-term changes were performed during 1999–2000, 2005–2006, and 2010–2011. Thus, the long-term coastal changes indicate that the net erosion rate is higher on the coasts of Kanyakumari, Kovalam, Manavalakurichi, Mandaikadu, and Thengapattinam; the values are 0.118, 0.105, 0.127, 0.133, and 0.017 m2, respectively. Meanwhile, the annual erosion rate of these areas is 10,000, 9,000, 11,000, and 1000 m2/year. The coastal zones Ganapathipuram and Enayamputhandurai have experienced accretion; the net accretion rate is 0.271 and 0.081 m2, respectively. Coastal beaches, beach ridges, and marine terraces are predominantly disturbed by the hydrodynamic processes including wave action, littoral current, and intervention of littoral drift by the artificial coastal structures like groins, revetments, and seawalls. Moreover, the study area has been demarcated with site-specific erosion and accretion zones based on the frequent seaward or landward coastline fluctuation through geospatial technique.