Modelling Urban River Pollution Dynamics and Sources Using QUAL2Kw: Implications for Water Quality Management in the Cikapundung River

Abstract

Rapidly growing cities face increasing pressure from domestic and industrial activities, leading to significant water quality degradation. The Cikapundung River in Bandung, Indonesia, has experienced declining water quality due to intensified anthropogenic influences. This study aims to model pollution dynamics, quantify pollutant loads from multiple sources, and evaluate their implications for river water quality management. A combination of field measurements, secondary data, and the QUAL2Kw model was employed to simulate the spatial variation of key parameters, including biochemical oxygen demand, chemical oxygen demand, dissolved oxygen, and ammonia. Pollution loads from both point and non-point sources were estimated, and the model was calibrated and validated using observed data. Simulations were further conducted to assess the potential effectiveness of different pollution control strategies. The results reveal significant spatial variability in water quality along the river, with pollutant concentrations increasing downstream, primarily driven by untreated wastewater. Model outputs indicate that several river segments exceed permissible water quality standards, particularly for BOD and COD, reflecting high organic pollution loads. Scenario analysis demonstrates that reducing domestic wastewater inputs and improving waste treatment infrastructure could substantially enhance water quality conditions. This study highlights the critical role of integrated water quality modeling in understanding urban river pollution.