Empirical analysis of flood risk perception using historical data in Tokyo

Urban areas are vulnerable to natural disasters and require countermeasures to increase resilience. Cities located along coastal areas and rivers are increasingly facing flood problems. Urbanization in combination with climate change has increased localized torrential rainfall, causing more frequent floods in some areas. Local governments have implemented hard and soft measures to mitigate the potential impact; however, public awareness of flood risk is needed for these measures to be effective. This study exploited a characteristic of the hedonic price model and investigated changes in flood risk perception by assessing changes in land value over decades in flood-prone areas in Tokyo. The flood damage records show a decrease in flood damage in vulnerable low-lying areas, while the situation remains the same in high-lying areas. The land value of the most vulnerable area has increased more than that of less vulnerable areas. The results indicate that implementing effective measures and mitigating the impacts may diminish the awareness of flood risk, and the flood risk presented on the flood hazard map may not garner the expected attention. The findings also imply that investing in flood mitigation is worthwhile and could increase resilience in vulnerable areas. Furthermore, ensuring the precautionary acts of residents and confirming the effectiveness of reactive adaptation measures contribute to reducing future loss in the context of diminishing flood risk perception.