A SIMPLIFIED FLOOD INUNDATION MODEL INTEGRATING WITH RAINFALL-RUNOFF PROCESSES USING GLOBALLY AVAILABLE TOPOGRAPHIC DATA

Abstract

Flood hazard is one of the most harmful disasters in the world, and it is significant to obtain information on flood characteristics for hazard mitigation as well as vulnerability assessment. This paper develops a model for simulating flood inundation integrating with rainfall-runoff processes. The model is designed to operate with the Shuttle Radar Topography Mission (SRTM) DEM data and other globally open data sets, based on the simplified process representation capable of simulating flood inundation. It consists of a one-dimensional diffusion wave representation for channel flow and a two-dimensional diffusion wave approximation of overland flow solved using an explicit finite difference scheme. In the model, exchange of flows between river channel and overland surface is calculated through Manning's formula in response to the relative water surface elevation. Simulated results in the Maruyama River basin show an acceptable agreement with the observed flooded area. Hence the flood vulnerable area is able to be identified and delineated. This research is a fundamental step to assess flood hazard vulnerability at any global catchments.