Erosion and accretion rates induced by cyclones in the eastern GBM delta of Bangladesh are extremely high and the island of Sandwip has been reducing its original size in the last few decades, making its community more vulnerable to the impacts of climate change. An attempt has been made in this study to observe recent shorelines changes using remote sensing and GIS tools. In order to understand the nature of the small cliffs that occupies most of the island’s shoreline, a series of shorelines and cross-shore profiles were also surveyed in 2013 and sediment samples collected. The analyses indicate that the island has accreted between 1978 and 2006 in the northern and eastern parts, while the cliffs on the south and south-western parts have been eroding alarmingly. The accreted coast is very gently sloping while the eroding coast on the south-west of the island has a steep coastal slope. The eroding side is only about 5 meters above MSL while the accreting side of the island is 7.6 meters high. Grain size analysis found almost negligible amount of coarse materials (>0.63mm) in almost all sections and highest proportion (98%) of fine (<0.63mm) sediment in the most accreted newly formed northern profile section.

Coastline Change of a Low-lying Island (Sandwip) in the Eastern GBM Delta, Bangladesh

CIAVOLA, Paolo
2013

Abstract

Erosion and accretion rates induced by cyclones in the eastern GBM delta of Bangladesh are extremely high and the island of Sandwip has been reducing its original size in the last few decades, making its community more vulnerable to the impacts of climate change. An attempt has been made in this study to observe recent shorelines changes using remote sensing and GIS tools. In order to understand the nature of the small cliffs that occupies most of the island’s shoreline, a series of shorelines and cross-shore profiles were also surveyed in 2013 and sediment samples collected. The analyses indicate that the island has accreted between 1978 and 2006 in the northern and eastern parts, while the cliffs on the south and south-western parts have been eroding alarmingly. The accreted coast is very gently sloping while the eroding coast on the south-west of the island has a steep coastal slope. The eroding side is only about 5 meters above MSL while the accreting side of the island is 7.6 meters high. Grain size analysis found almost negligible amount of coarse materials (>0.63mm) in almost all sections and highest proportion (98%) of fine (<0.63mm) sediment in the most accreted newly formed northern profile section.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11392/2369671
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