A Coupled Hydraulic Numerical Models On The Urban Rain Flood

The number of flood disasters worldwide has been increasing significantly in recent years. This partly due to a changing climate, urbanization, increasing utilization of flood plains, and a reduction in the natural retention capacity of catchments. In fact, the rainfall and storm water produced flood is one of the most severe natural disasters especially for urban areas. Rainstorm can generate a large amount of surface storm water in a short period due to the high intensity rainfall and an inadequate sewer system. This leads to local flooding in an urban area including of streets, roads, residential houses, and commercial districts.In this study, a coupled one-dimensional and two-dimensional numerical model is developed to simulate a local rainfall produced flooding process over an urban area. The model results provide us with the spatial flood risk information, as water depth, inundation time and flow velocity during the flooding. The model can be a new tool in flood risk study. It is very useful in the decision making a flood prevention and evacuation for many agencies.An extensive literature review is done for hydrological and hydraulic methods and models in flood study. The work for this research is summarized in the following ways.(1) Developed the one-dimensional model. The model aims to simultaneously handle equations of flow through the sewer system and surface flow. The algorithm is obtained through the apatial discretisation of the shallow water equations based on techniques as stagger mesh and semi-implicited methods. The Preissmann fictitious slot is utilized to compute the flows may be either free surface (subcritical or supercritical) or pressurized in pipes. The limited waterdepth method is used for the wetting and drying interface. Particular attention is posed to the numerical treatment of the accuravy, the stability and the reliability of the code that tested on the selected study cases.(2) Developed the two-dimensional model. The model simulates storm water process over ground, which initially is dry. The finite volume method is used for the continuity equation and semi-implicit method is used for the momentum equations and the sime-lagrangian methods are used for the convection term, which keep the model stability. Numerical model was tested by the physical modeling of the Toce river valley, Italy, which considered as representative of a real life flood occurrence.(3) Developed the coupled one-dimensional and two-dimensional model. The model presented in the paper tries to solve the problem of interactions between two components which...