Professor, Shibaura Institute of Technology, Japan

Speech Title: Quantification of Flood Risk Considering Global Climate Change with Flood Risk Impact Factor (FRIF) in Urban Drainage Areas

Abstract: Various factors such as urbanization, flood control projects, non-structural measures, and climate change increase flood risk in urban catchment areas. This study produces a flood risk structure through flood risk analysis and flood risk assessment to calculate flood risk costs for various environmental catchment conditions in a framework of urban flood risk management. The concept of flood risk in this context is defined as the product of flood damage and the probability of its occurrence. The study presents a methodology for comparatively evaluating the impact of the flood risk factors using a GIS-based flood damage prediction model (FDPM). The FDPM calculates flood inundation depths using the XP-SWMM routine and monetary flood damages using a flood damage estimation model for various storms and catchment conditions. In particular, the increased cost of risk caused by climate change can be estimated from the difference between the potential damages before and after the predicted climate change using the Return Period Shift Method (the RPS Method). The changes in risk cost in various catchment conditions are finally translated into the FRIF (flood risk impact factor), which is defined as the ratio of the change in risk cost to the present risk cost.