Accurate flood risk assessment is useful for mitigating the hazards of dam break floods. Flood inundation may cause serious damage to human lives, property, and river environments. In many countries, flood risks are assessed to establish flood mitigation plans against unexpected flood events. Flood risk maps are based on inundation depth and maximum flow velocity obtained from numerical models based on shallow-water equations. Flood intensity, defined as the product of flood depth and velocity, is used to assess risk in vulnerable areas of many European countries. The inundation flow is affected by structures such as buildings and houses. In this study, changes in water depth, velocity, and flood intensity that are associated with arrangements of structures are numerically investigated. A numerical model is formulated using a finite volume approach and is first verified for available test problems. The effects of structures are then tested by measuring flood characteristics in an experimental basin in which various arrangements of model structures are placed. The measured flood characteristics are then compared to the numerical results.