Investment decision support for business sustainability improvement based on flood inundation simulations with a variety of extreme rainfall scenarios

Abstract

In recent years, heavy rainfall disasters have occurred frequently in Japan, which increases the importance for private companies to take flood countermeasures to prepare improved business continuity plans (BCPs). Although river authorities have published flood hazard maps for design rainfall and probable maximum rainfall in Japan, hazard information for floods with other return periods is also required for the target business facilities to make cost-effective plans and investment decisions based on flood risk assessment. In order to overcome the situation where public flood hazard maps do not provide enough information for risk-based business continuity planning, we developed a method to provide tailored flood risk information for a business site based on a series of flood inundation simulations for rainfall scenarios with various return periods in the expected inundation area of the Tama River, Tokyo, Japan. Calculated results showed that the inundation characteristics highly depend on the topographic features of the flood plain, suggesting the importance of assessment at a respective business site. We also present an example of the application of the proposed method of simulation results in designing the BCP.