Water pollution in urban river basins is a problem due to pollutants from cities and seawater intrusion. To improve water quality, different methods like sewage system upgrades, controlling sewage plant discharges, using aquatic plants to remove nutrients, and dredging sediments have been studied. A field survey was done in a typical urban river basin, followed by creating a mathematical model to simulate water flow and quality. Different purification options were evaluated based on their effectiveness and cost, with priorities set. This study shows how to plan river water quality management effectively.