Analysis of the Wetland Degradation around the Vicinity of Dhaka City in Bangladesh

Abstract

Degradation of wetland creates adverse impact on natural environment, ecosystem and on drainage congestion. The situation is more alarming in case of urban areas especially Dhaka and its adjacent areas. The objectives of the study are to determine the status of wetland reduction around Dhaka city in terms of extent of area and causes responsible for degradation. Satellite images of 1967, 1977, 1989, 1999, 2009 and 2010 have been used for preparing permanent wetland maps while satellite images of 1996 and 2009 have been used for preparing seasonal wetland status. Analysis showed that extends of permanent wetlands have been reduced in all the study areas during 1996-2009. Wetland degradation was found to be worse in eastern Dhaka followed by western Dhaka and Dhaka-Narayanganj-Demra (DND) areas. In case of Seasonal Wetlands, western Dhaka showed almost twotime more degradation than that of eastern Dhaka in case of areal extension, when the same period of 1996-2009 is considered. Extensive increase of population and commercially productive use of land within the city are mainly responsible for this degradation. Demand driven urban growth that has profound adverse effects on the water resources and the wetland system in Dhaka have caused adverse impacts on the drainage systems. Unplanned urbanization has hampered the natural state of drainage, and hence caused sudden inundation and water-logging. Another major reason for seasonal wetland degradation is loss of the connectivity of floodplains within the study area.