Ferdous, J.
Rahman, M.



Year of Publication:



Wetlands form a unique mosaic of habitats with an extremely rich diversity of flora and fauna, which are invaluable components of the environment, ecology, resource potential and biodiversity in Bangladesh. Wetland systems are vulnerable to changes in quantity and quality of their water supply, and it is expected that climate change will have a pronounced effect on wetlands through alterations in hydrological regimes with great global variability. Especially, wetlands of Dhaka city have experienced significant changes in recent periods, which has triggered the heat island effect. This study aims to detect the change in wetland areas of Dhaka city using the Landsat images of post monsoon period of the year 1988, 2002 and 2016. For identifying the wetlands, threshold value of Normalized Difference Water Index (NDWI) has been used. Analysis revealed that the wetland area of Dhaka city has been decreasing day by day. Almost half of the wetland areas have been converted into other land uses during 1988 to 2016. In 1988, 43.08% areas were under wetland category, where it has reduced to 26.97% in 2002 and 12.13% in 2016. The decreasing rate of wetlands is 71.84% between these 28 years. For this significant reduction of wetlands, the microclimate of Dhaka city has experienced warming, urban heat island effect in concise. Habitats of diversified flora and fauna have destroyed. Moreover, it has destroyed the connectivity among the water bodies of Dhaka, which may cause severe waterlogging problem in Dhaka. Urban flooding may induce by this change in wetlands as they are not capable of holding a huge amount of rainwater at present. So conservation of wetland areas is a prerequisite task to promote sustainable development plan for Dhaka city. Policymakers should focus on this topic before formulating any land use or detail area plan for Dhaka City.

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