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Spatio - Temporal Change Detection of Shoreline outside of the Coastal Embankment of Bangladesh: The Case Study on Barguna Sadar Upazila, Barguna District

Corresponding Author : Md. Bahuddin Sikder (bahuddinsikder@gmail.com)

Authors : Md. Najmul Kabir

Keywords : Shoreline, Coastal Embankment, NDWI, DSAS

Abstract :

The main aim of this study is to delineate the shoreline change outside of the coastal embankment of Bangladesh. To fulfill this purpose, choose Barguna Sadar Upazila as a study area due to its unique position. This site is located at such a place where west and east side situated near the bank of the Bishkhali and Payra river, and in the south, the Bay of Bengal and these two rivers formed an estuary, which is the breeding place for erosion and accretion. To analyze the changing pattern of shoreline, followed geospatial techniques. First, NDWI method used to delineate the land and water from the satellite images. Then, DSAS version 4.4 tool is used to detect the pattern of shoreline from the year 1980 to 2017. From the analysis, it is obtained that the study area gained almost 449.10 hectares of land (1980 - 2017) as well as the length of shoreline is increased (1.05 km). The whole study area is divided into 113 segments. Amongst them, 92 shows positive movements, and the remaining shows negative movement. The highest movement is observed in the middle part of the study area (in the estuary, the movement value is 680 m), wherein the lowest is observed in the east side (-170 m). It is obtained from the analysis that the movement is seaward and the changing rate is -4.0 to 18 m per year. From this observation, it might be concluded that the study area is dominated by the accretion process rather than erosion. Due to this reason, the vulnerability level based on shoreline change is low.

Published on December 30th, 2019 in Volume 29, Issue 2, Physical Sciences