Over populationDhaka is one of the most densely populated cities of the South- Asian countries. the city has a long history dating back about 400 years 6. The city went through phases of growth and decline from its beginning as a city with a small population to its current state as a tremendously expanded megacity. Due to rapid urbanization process, the city is emerging as a mega-city and this trend generates numerous economic and social externalities and social costs such as deterioration of environmental quality, increased pollution and congestion. Dhaka City is beset with a number of socio-environmental problems. Waterlogging, traffic congestion, solid waste disposal, black smoke from vehicular and industrial emissions, air and noise pollution, pollution of water bodies by industrial discharge etc. are problems of the city This transformation has been consistently threatening social and environmental realm indicated by depletion of garden houses; reduction of public parks; shrinking walkways; deletion of setback for ventilation and sun shade from trees; slowing down mobility; and obstruction of physical and visual permeability During the Industrial Revolution, people began moving into the cities to work in the factories and industries that would change or eliminate their previous jobs in rural communities. While this helped cities to grow exponentially, it brought with it a number of social problems and conflicts.Decrease of wetland and open space In the process of urbanization, the physical characteristics of Dhaka City are gradually changing as open spaces and water bodies are converted into built-up areas. The City has spread over the years in all directions and such expansion has caused shrinkage of the wetlands 4.An ever-increasing trend of wetlands loss is found in DMA between 1978 and 2009. In 1978, 130.27 km2 wetland existed which reduced to 127.85 km2 in 1988 at a rate of 1.86 in that decade. This change was quite an insignificance in comparison to next decades. About 20.92 km2 of wetland was lost between 1988 and 1998 which was about 16.07% of existing wetlands in 1978. This rate of loss of wetland in DMA was almost tripled in next decades. About 40.96 km2 of wetland was lost from 1998 to 2009 which was about 40% of existed wetland in 1978. Overall, about 76.67 km2 of wetlands were lost between 1978 and 2009 (Figure 3).This changing trend of wetlands makes the drainage system of Dhaka City vulnerable, creating waterlogging problems and their consequences. Landfilling and encroachment were recognized to be the main reasons for shrinking of the wetlands in the city. Development and alteration of the existing water bodies should consider the natural hydrological conditions.A large number of researchers have been done to study the impact of urbanization on flooding situation.