Floods in urban areas due to levee overtopping and/or breaking may cause a lot of severe damage of property and lost of human lives. In case of river dike and/or dam break, the problem is characterized by the overland propagation of discontinuity fronts or hydraulic jumps. !t is of immense importance that urban planners and personnel have tools to assist in predicting and evaluating beforehand the flood process in such incidents. Recently, with the rapid development of computer resources and numerical methods, numerical models based on mathematical models for simulation of flood scenarios become highly useful. A model for the simulation of two dimensional (20) overland floods in urban areas has therefore been developed. A finite volume Godunov-type numerical scheme is applied in the model. This numerical scheme has some important advantages. It is a conservative scheme and able to model more accurately hydraulic shockwave propagation. The scheme is based on unstructured computational meshes, in general, to deal with complicated urban geometries. The model has been applied to studying two experiments of overland floods. These experiments were carried out in research institutions in Japan and Italy. The computed results show general agreement with the measured ones. The model is prospective for analyzing overland flood process in practical cases.
