Study on the Change of Riverbed of Hau River at Chau Phu District, an Giang Province by 1D2D3D Combined Numerical Model

Using integrated models is now a trend in hydraulic and sediment transport simulation. Models can be integrated from 1D, 2D, and 3D submodels. The 2D model and especially the 3D model allows detailed calculation of the flow and the process of sedimentation and erosion of the channel. However, 2D and 3D models are not suitable for large-scale problems because they require a lot of computer resources as well as running time. Although 1D modeling is not capable of detailed computation, it allows large-scale simulations. Combining 1D, 2D, and 3D submodels will allow the creation of an efficient model that can both perform large-scale problems and allow detailed calculations of areas of special interest. Besides, the model also solves the problem of boundary conditions of detailed models. In this paper, a 1D2D3D combined model that calculates and simulates the bed evolution of the Hau River section flowing through the Chau Phu district is introduced. Methods of calculation and combinations of submodels are presented. The simulation results show that the model reflects quite well the reality of the river section.