ABSTRACT
River water quality models are used extensively in the design and assessment of water quality management measures. This chapter introduces the effects of river hydraulic properties and river reaction kinetics on its self-purification ability and discusses the use of water quality models to simulate the self-purification ability of a receiving river for the organic waste and other traditional pollutants. Focuses are made on the changing mechanisms of DO in a river by considering the combined effects of dispersion, atmospheric reaeration, and biochemical consumptions. An analytical solution for a one-dimensional water quality model (the Streeter-Phelps model) is presented, followed by the discussions of its derivation and applications. The commonly used numerical models for river water quality, QUAL-2K, WASP, and HEC-RAS, are introduced with the selected case study. Finally, the alternative linear system approach based on integral equations is introduced and discussed.
