Author(s): M. Monowar Hossain; Rashedul Islam Md
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Abstract: Dhaka, the capital of Bangladesh is situated on the bank of river Buriganga. Over the last few years, environment and its pollution in the river Buriganga has been a growing concern for Dhaka city dwellers. Not long ago, the Buriganga was a beauty of Dhaka city and people used the clean and transparent water for amusement and recreation and for other purposes. Now the water has become dirty, the river has been encroached by illegal occupants and the river environment has been polluted. A study has been conducted on the Buriganga to assess the magnitude of encroachment and as a result, reduction of conveyance capacity, which has a direct impact on some environmental parameters. The study includes collection of some data related to pollution and their analysis. Data on physical encroachment, shrinking of the cross section and water quality analysis are presented for a number of years. It is revealed that the water pollution increases tremendously over the last few decades and from analysis it appears that Buriganga would be carrying mostly polluted water if the present trend of increasing pollution continues. From 1968 to 1992, BOD increases from 0.8 to more than 3 mg/l, DO reduces from 6.7 to less than 5 mg/l in most places. In addition, presence of heavy metals in the water at a higher value than that of allowable value was detected. Shrinking of channel area and rising of bed is found due to the heavy BOD load and sedimentation. Analysis of cross-sectional area shows a gradual reduction in area with time. As a result, discharge capacity reduces and high floods of long duration are experienced. Finally some recommendations are put forward to ameliorate some of the problems.
Year: 2003