In this study, the effects of urban areas against flood waves due to a dam failure were numerically investigated based on the two physical experiments. The applied numerical model is a two-dimensional unstructured finite volume model based on the shallow-water equations and HLLC scheme. The water depths predicted at specific points showed good agreement with available measurements. In the first experiment, a relatively high water depth and the delay effect of flow at the front of urban areas are observed. The urban areas may become a large obstacle against the smooth propagation of the flood wave. In second one, as the inflow at the upstream boundary is entered to urban areas, the water surface elevations can be classified into abruptly decreasing portion and slowly decreasing portion. The first arrival time to the front of urban areas is decreasing with the increasing inflow.