Bottom-up approach for flood risk management in developing countries: a case study in the Gianh River watershed of Vietnam

Abstract Flood effects are very serious, especially in developing countries where they are at high risk due to urbanization and socio-economic development. Reliable information is crucial to support decision-makers or planners to develop appropriate strategies to reduce flood risk. This article aims to develop a theoretical framework for assessing flood risk and adaptive capacity based on a bottom-up approach, in the Gianh River watershed of Vietnam, considered a very important task for flood risk management. Flood risk was computed by combining hazard, exposure, and vulnerability using hydrodynamic modeling and the Analytic Hierarchy Process method. The adaptive capacity of the population was assessed via interviews with 298 inhabitants. The results show that flood risk is high in areas with high population and construction density. Both the ability to access resources and communities' perceptions are important factors in improving the capacity to adapt. This study can provide an important theoretical framework complementing the existing literature and supporting studies related to flood risk management in the context of climate change and urbanization in other regions. Besides, the study fills in a gap in the knowledge of negative flood effects, providing important inputs for decision-makers to develop appropriate strategies for reducing damage in Vietnam and other countries in the world. From a methodological start point, this study underlines the importance of using hydraulic models and socio-economic surveys in flood risk management.