Research On Several Key Technologies And Their Implementation Towards A Flood Control Modeling Software Package Within River Systems

Flood prevention and disaster reduction is a long-term agenda and an arduous task in China. China flood control command system will provide decision-support for flood control and disaster reduction nationwide. As to decision support for flood control, the key component is flood dispatching within river systems. Flood modeling in river systems will help to make reasonable flood control decision under various scenarios of flooding occurrence. In this paper, the author first brings forward the components of river systems and the context of flood modeling, and then puts emphasis on flood modeling software package development for river systems. This paper discusses several key technologies and their implementation on flood modeling within river systems.1 One-dimensional unsteady flow modeling in river networkStarting from the deduction of the integral form of the governing equations, the author introduces the Newton's Iteration method for one-dimensional unsteady flow modeling in river network.2 Steady flow modeling in river networkIn order to guarantee the convergence of iteration method, steady flow analysis should be performed before the unsteady flow modeling. This paper introduced Monte Carlo Method, also called random walk method,for steady flow analysis in river network.3 Boundary-fitted mesh and elevation variance adaptive mesh generation In two-dimensional flood modeling within river systems, the impact of dykes and irregular boundary is very important, meanwhile, the ground elevation is also a main factor that should be taken into account. In this paper, the author discusses boundary-fitted mesh generation and adaptive mesh generation due to elevation variance.4 Simplification of flood modeling in detention areaIn this paper, the author brings forward the idea of simplified flood analysis method in small and flat detention area. One is based on digital elevation model, another one is based on quasi-two dimensional modeling originated by J A Cunge.5 Development of one dimensional river network modeling software Based on the theory of one-dimensional flood modeling in river network and the special GIS platform developed using C#, this paper takes a creative exploring towards establishing a software package for one-dimensional river network flood modeling under the latest software development technology. The author developed the flood model using C#, ensured the seamless integration with the developed GIS platform. According to the requirement for a software package, the author further discusses the automated construction of topological relationship between rivers within a river network, as well as the visualization of modelingresults.6 Development of 2-d flood modeling softwareThe author mainly discusses the two-dimensional mesh generation and the post-processing of 2-d flood modeling. The author develops a mesh-gen for body-fitted mesh generation and irregular triangle or quadrilateral mesh generation. In post-processing of flood modeling, the author mainly discusses the visualization of flooded area and flow field.7 Integrated flood modeling systemAt the end of this paper, the author puts forward an idea for integrated flood modeling system through the topological relations between objects within a river svstem.