Analysis Of Flow And Water Quality In River Networks By Using One-dimensional Numerical Model

With the much focus and financial support on the water environment regulation, it is become more and more important to study the flow movement and water quality change in river networks under tidal influence. Through the numerical method, flow movement and water quality can be analyzed, and it is the major part for analysis the objectives of water pollution control planning. A one-dimensional hydrodynamic and water quality model for river networks is developed, according to hydraulics and water quality features of water body within a tidal river network. The model is verified firstly and then applied to Qijiang River network, according to the physical circumstance for the harness of water pollution control programming. Through the research of this paper, the following achievement is mainly obtained:1. The hydrodynamic model is developed in this paper, in which Preissmann weighted implicit scheme is used, and three steps method is also applied. Calculations are shown that this scheme is effective to simulate tidal river and it can get better accelerating and is stable.2. An unsteady water quality model for one-dimensional river network is established by using FVM, a junction discrete equation is introduced according to its character. A formula of stage solution of water quality model is established, and the effective linking for the hydraulic model with water quality model is built up according to the relationship between junctions. Verifications shown that this formula in combination with channel simulation method presented in this paper can not only enhance the calculation accuracy for tidal channel network water quality simulation, but also raise the speed of solution.3. The model is applied to Qijiang River for the harness of water pollution control programming. By using of the model, the water leveh discharge and the water quality consistency distribution of the river are obtained, and the optimized managing scheme is find which is provided for decision-making engineering measures.