Research And Application Of Hydrodynamic And Water Quality Model In Net Rivers

As one of the main approaches to study river networks flow and pollutant transportation and diffusion in water bodies, numerical simulation method can provide the essential technical support to the decision of water environmental management strategy. And the key point of the practical simulation is to estalish a feasible, reliable and efficient model, it has great significance both in theory and practice.In this dissertation, based on the Saint-Venant equations, one-dimension (1-D) hydrodynamic model for river networks was established using Preissmann implicit scheme and the river-junction-river method. Based on 1-D convection-diffusion equation, 1-D water quality model for river networks was established. The treatment of river section and the facilities in the river networks, like dams, weirs, was also studied. Then the models established were validated using analytical solutions. The results showed that the models were credible and could be widely used for 1-D simulation and prediction of river flow and pollutant transportation and diffusion.Based on two dimensional (2-D) shallow water equations and 2-D convection-diffusion equation, the 2-D hydrodynamic and water quality models were established for lakes, reservoirs and estuaries and other wide water areas. Coordinate transformation method was used to solve the complicated boundary. The 2-D models were validated by analytic solutions, the results proved that the 2-D models could correctly reflect the movement of 2-D water flow and pollutant transportation and diffusion, and could be further applied to study the real 2-D waters.Based on the 1-D and 2-D models established above, the coupled model was built using overlap - projection method .And then the model was validated by an example. The 2-D modeling of the local reservoirs, lakes and other wide water areas in the river networks could be simulated by this model.The 1-D hydrodynamic model was applied to the Beiyunhe river, the simulation and prediction were applied in the section from Yulinzhuang dam to Tumenlou dam and the section from Beiguanzha dam to Tumenlou dam. The results were compared with the measured data, and the reliability of the model was further validated.