Geomorphological change assessment of south western coastal region: a case study of Mongla Upazila, Bagerhat, Bangladesh

Erosion and shoreline changes are found at a higher rate in the southwestern coastal area due to its dynamic characteristics. The present study aims to evaluate the geomorphological changes through observations of satellite imagery in Mongla, Bagerhat. Study conducted from the years of 2000–2018 using the Normalized Difference Water Index (NDWI) and image classification method in ArcGIS software. According to the analysis of multispectral satellite imagery, it is revealed that about 22.57 km2 land area eroded consecutively over the last 18 years as well as the areal difference of land and water measured. Changes of shorelines figure out that in some vulnerable cross-sections about 366 m area is displacement. Though, this area located in the tidal zone but ocean connected areas of Sunderbans and lower regions of the populated area faced mostly the effect of geomorphological changes.