Inundation Model Integrating with X-Band Polarimetric Radar for Flood Disaster Prevention in Urban Area

This paper introduces a development of integrated system for flood inundation mapping in urban river basin by integrating radar observation and inundation model. An accurate high-resolution estimation of rainfall from X-band polarimetric radar was supplied to distributed hydrological model to simulate flood hydrograph due to severe rainfall. Flood stage hydrograph was obtained from 1-D flood routing model. An inundation map was produced by 2-D inundation model for highly urbanized area which considers the spatially distributed rainfall input from radar. An absorbing boundary condition is applied to the inundation model in conjunction with the explicit MacCormack and artificial viscosity scheme. The model was applied to simulate and to evaluate the past storm events in Kofu city, Japan. The validated hydrological model can reasonably simulate flood hydrograph using radar-rainfall estimates. Compared to observed inundation, the model was satisfied to provide a flood hazard map in dense urban area. The system would be useful for local government effectively plan the appropriate countermeasures.