Coastline change and coastal islands development in the Feni estuary of Bangladesh through RS and GIS

In coastal areas, to take any development plan, it is important to determine the stability of the coast and coastal islands. Therefore, the present research took an initiative to illustrate the development of coastal islands in the Feni estuary of Bangladesh through Remote Sensing (RS) and Geographic Information System (GIS) techniques. Multi-dated Landsat images of 1978, 1989, 2014 and 2020 were used in the study. The research reveals that in 1978, 1989, 2014 and 2020, the total area of various islands in the estuary was 377,650,894 and 1063 km2, respectively. The islands show cyclical growth and erosion, but their main components have existed for decades. During the period from 1978 to 1989, 1989 to 2014 and 2014 to 2020 about 330,386 and 379 km2 of new land added to the existing land mass and about 57,142 and 210 km2 of existing land eroded, respectively. Finally, from 1978 to 2020, the size of the islands increased by about 14.64 km2 yr-1. During the same period about 110 and 40 km2 lands along the coastline were eroded and accreted, in the north-western and eastern parts of the estuary, respectively. The study further reveals that the islands of the estuary have developed over the past few decades, except Sandwip. Finally, the outputs of this study will be helpful for policy makers and planners for sustainable estuary management.