A STUDY ON HYDRODYNAMIC AND MORPHOLOGICAL ANALYSIS OF KARNAFULI RIVER USING DELFT 3D MODEL

Abstract

The Karnafuli River is Bangladesh's third-largest river and plays very significant role in the country's economy, serving as a lifeline for the Karnafuli River Port and providing water for industry and agriculture. Along the bank of the river Karnafuli, activities of the Chittagong Port Authorities (CPA) and other organizations are growing every day. However, pollution and erosion are serious issues that threaten the river's health and the wellbeing of nearby communities. Erosion and sedimentation have also increased due to the construction of dams and infrastructure projects. Keeping rivers dynamic and alive in terms of navigability is therefore always important. So, the use of a 2D model in the river Karnafuli is vital to studying the effects of any river intervention. This study uses Delft3D to create a 2D model to evaluate hydrodynamic and morphological properties and behavior of the Karnafuli River. Time series data on outflow and water level are used as boundary conditions, and the model is calibrated using the water level recorded at Khal 10 in June 2020 and validated there for the months of November 2020. The model was modified to match changes in bed level observed in the data following calibration and validation. This assessment studied the hydrodynamic and morphological characteristics of a river, finding Velocity and sediment transport are closely related, with higher sediment transport during the wet season leading to erosion and depositing of the river bed. In contrast, there is less erosion deposition during the dry season, Khal 18. The downstream section of the river faces more tidal effect than the upstream section, Khal 10. Khal 12 is a bending portion where the maximum velocity is found, and downstream is where the minimum velocity is discovered. Hope so the results of the model simulation should be useful in predicting the impact of any future development work to be implemented on this river, and it is intended that the findings of this evaluation will help to comprehend the overall hydrodynamic and morphological changes of the river.