Micro-level coastal vulnerability assessment in relation to post-Aila landscape alteration at the fragile coastal stretch of the Sagar Island, India

Abstract

After the Aila cyclone on May 25, 2009, the fragile coastal environment of the Sagar Island is facing harsh impacts associated with coastal erosion, landscape degradation and alarming socioeconomic pressure. The present micro-level study focuses on the shoreline dynamics and associated landscape alteration rate of different land use/land cover patterns over 2.24 km2 area, along about 3 km coastline at low-lying (1.45 m) fragile land-shorefront stretch of the Sagar Island, India using multi-temporal satellite images of pre-Aila (2006) and post-Aila (2010 and 2017) periods. The embankment and shoreline shifting trends and predicted positions are estimated through the digital shoreline analysis system (DSAS) considering multiple shoreline/embankment positions over the period of 2006 to 2017. About 0.64 km2 area of productive land is exposed to marine action due to the rapid rate of shoreline retreat (28.48 m/y) within the decade. The coastal vulnerability index (CVI) is estimated after considering the 14 parameters from physical and socioeconomic variables. The result reveals that the shorefront zones (3 and 5) are highly vulnerable with CVI of 1 and 0.494 than the interior zones (2 and 4). The estimated vulnerability divulges that in the near future, the entire area will ruin due to high rate of land erosion with triggered effects of the local sea level rise (SLR) and associated hazards. The adopted multi-criterion CVI estimation method can also be applied over a large area in the other coastal stretch of the tropical regions.