Comprehensive Physico-Chemical Assessment of Surface Water Quality in Hatirjheel Lake, Dhaka, Bangladesh.

Abstract

Rapid and largely unplanned urbanisation has resulted in severe pressure on surface water bodies in Dhaka, Bangladesh. Hatirjheel Lake, situated in the heart of the city, is simultaneously a flood-retention basin, a hydraulic conveyance link, and a major recreational space. This paper presents a detailed yet compact physicochemical assessment based on primary data for three surface-water sampling locations in Hatirjheel, collected in September (the late monsoon/post-monsoon period). The lake water was analysed for pH , temperature, biochemical oxygen demand ( BOD_5 ), chemical oxygen demand (COD), dissolved oxygen (DO), electrical conductivity (EC), total dissolved solids (TDS) and total hardness, following Standard Methods for the Examination of Water and Wastewater. In addition, pH data were available for six samples collected in September 2025 and October 2025, allowing a limited two season comparison. Urban lakes in rapidly growing megacities are often under severe pressure from untreated wastewater, storm runoff and intense human use. Hatirjheel Lake, located in the centre of Dhaka, Bangladesh, is a key element of the city’s drainage and recreation system but has been repeatedly reported as degraded in terms of water quality. In this study, surface water samples were collected from three locations in Hatirjheel during September, and pH data from a previous February survey were also considered. Physico–chemical parameters including pH, temperature, biochemical oxygen demand (BOD), chemical oxygen demand (COD), dissolved oxygen (DO), electrical conductivity (EC), total dissolved solids (TDS) and hardness were analysed following standard methods. The results show that pH (7.5–8.0) remained within the permissible range of the Bangladesh Environment Conservation Rules (ECR’97), while EC, TDS and hardness were moderate. However, BOD and COD substantially exceeded national guideline values, and DO at some points dropped below the recommended minimum, indicating organic pollution and potential stress on aquatic biota. The findings are consistent with earlier studies that highlighted the impact of combined sewer overflows and urban runoff on Hatirjheel water quality. The paper concludes with recommendations for improved sewer management, regular monitoring and integration of water quality considerations into future lake management plans.