ABSTRACT
For complex problems such as unsteady inflow or irregular river channels, the mass transport equation and hydrodynamic equation in water environment model are PDEs, which cannot be solved by simple analytical models, rather they require numerical solutions in general. This chapter introduces two most commonly used numerical methods in water environment modeling analysis, namely, the FDM and the FEM. First, the basic conception and scheme construction method of the two numerical methods are introduced. Then, different schemes for convection equation and diffusion equation are presented and discussed. Finally, the applications of the two numerical methods for solving the typical governing equations in two popular water environment model, QUAL-2K and SUTRA (Saturated-Unsaturated Transport), are presented.
