| In order to simulate both river discharges and inundation areas with rainfall input、we developed a new rainfall-runoff-inundation model. The main feature of the model is to simulate discharges and water levels on a two-dimensional basis instead of one-dimensional simulation often conducted with typical distributed rainfall-runoff models. Two-dimensional analysis enables to simulate water movement even on flat areas where flow directions and velocities are determined by both topography and water levels. In addition、unlike typical inundation models、the developed model can simulate not only surface flow but also subsurface flow processes since the latter processes play an important role in many regions. To solve basic equations、we applied a diffusion wave approximation that is numerically more stable than solving fully dynamic equations. The developed model was applied to large areas (more than 15、000 square km with about 500 m resolution) covering parts of Hyogo and Kyoto Prefectures in Japan to simulate floods caused by Typhoon No. 23 in 2004. The model application showed high p0erformance in simulating river discharges as well as inundated areas by comparing with observed data. The newly developed model may be useful for flood predictions and flood risk analyses at regional scale. |
