Research and Application of 1-D and 2-D Coupling Water Environment Numerical Model for Taihu Basin

The water movement and water quality components transportation in Taihu Basin are very complicated under the complex water regime and interlaced river-lake water system. A 1-D and 2-D coupling water environment model is developed to simulate the variation characteristics of water flow and water quality components in this area. The model includes two parts: lake and surrounding rivers. Lake flow movement and transport of water quality components are calculated with 2-D unstructured finite volume method, which can fit complex geometry boundary and treat wetting/drying process. 1-D approach is applied in the network with surrounding rivers. The Saint-Venant equations used can calculate the floodplain and the main channel convergence of natural compound rivers. Based on non-complete mixing method of cross- section concentration, the water quality model is build up and loosely coupled to the river network hydrodynamic model by using the overlapping projecting method. To validate the present model, it ran for water flow calculation of Taihu Basin in 2000. Results show that the present model successfully simulated the water flow characteristics in the lakes and the flood routing in this system.