Impact of greater Dhaka city flood protection works on the environment with specific reference to industrial waste disposal

Abstract

This particular study mainly concerns the assessment of the impact of greater Dhaka city flood protection works on the quality of water bodies particularly due to industrial waste discharges. In this study the polluting industries situated within the embankment are identified and classified based on their pollution potential. Water Samples from Hazaribagh area, Tejgaon IIA (Begunbari Khal) and Dhanmondi Lake have been collected and tested and their effects on aquatic life and other environment are discussed. Water quality data for Buriganga river near Hazaribagh tannery and Chandnighat WASAintake have been collected from the Department of Environment (DOE)and analyzed in order to assess the changes in river water quality due to industrial discharges. The study reveals that waste discharges from the industries in Hazaribagh area have greatly impaired the quality of water bodies impounded due to the construction of flood protection embankment. The water of Begunbari khal which receives industrial discharges from Tejgaon IIA is already heavily polluted and found under septic condition during dry weather period. Construction of the 2nd phase of the flood protection embankment would only accelerate the degradation of the khal water quality. The study also finds that due to the presence of greater Dhaka city flood protection works, the industrial wastes (tannery discharges) are getting accumulated in the impounded water area in the city side of the embankment in Hazaribagh area to a great extent and this water environment is not suitable for fish and other aquatic lives and emits bad odour. The areas affected by bad odours from Hazaribagh tannery in post-embankment period are much larger than those of pre-embankment period and during dry season the area submerged by tannery wastewater in post-embankment period is approximately 8-10 times larger than that of pre-embankment period. The quality of Dhanmondi lake water has been found to be gradually deteriorating over the years. The present water quality situation of the lake appears to be not suitable for bathing, cooking or other activities.