Impact of Urban Expansion on Surface Water Bodies in Dhaka Metropolitan Area of Bangladesh: A Remote Sensing and GIS Based Analysis

Abstract

Purpose: In previous time, there were large amount of water bodies in Dhaka Metropolitan (DMP) area but due to various development activities, it has been shrinking with the passage of time. This research investigates the changes amount of water bodies in DMP area and find out how much built-up area are developed on water bodies in last 30 years. Methodology: The Landsat satellite data of 1989, 2002 and 2019 have been generated with unsupervised classification techniques which is used here to identify the water bodies and built-up area with the help of remote sensing and GIS based software like ERDAS IMAGINE, Arc Map 10.6. Findings: According to the study, the reduction rate of water bodies in DMP is high as the built-up area is increasing rapidly. In the last 30 years almost 2066.28 hectares water bodies are reduced while 1180.46 hectares are transformed into built-up area. Limitations: To collect the data of total water bodies in DMP area would bring more elaborate information but it would be time consuming and involved more authentic survey by related authorities. Practical Implications: As Bangladesh is highly populous country and its urban growth is rising rapidly, the balanced urbanization program for built up area is really needed according to ecological system. The diminishing of water bodies are happening for exploitation which is an alarming concept for scarcity of fresh water and proper drainage system. Originality/Value: Findings from this study can contribute in the urban planning, drainage planning and balancing the systems with topical processes for the eradicating the reduction rate of water bodies.