Calculation of Flood Control and Drainage Benefits of Levee Projects Considering Socio‐Economic Changes

Traditional methods for assessing levee projects focus solely on single‐year economic data, evaluating only the reduction in flood‐related economic losses while neglecting the benefits of saving lives and the dynamic changes in the economy and population over the project's design life. This study introduces a dynamic evaluation method for flood control and waterlogging drainage benefits of levee projects, incorporating economic and demographic changes. The total benefits are categorized into economic and life‐saving components. Separate hydrodynamic models for flood routing in river channels and rainfall‐waterlogging models in the basin are established. Through comparative analysis (with and without projects), the number of lives saved and the economic benefits generated by flood control and waterlogging drainage can be estimated. The Value of Statistical Life (VSL) is used to monetize life benefits, and calculation methods for flood control and waterlogging drainage benefits that considers both economic and life benefits are proposed. Then, a dynamic model incorporating regional GDP growth rates and population change coefficients is constructed, which can quantify the above‐mentioned benefits over the project's lifespan. A case study demonstrates that annual benefits increase from CNY 10.6 million in the base year to CNY 34.4 million by the end of the design life, with flood control benefits accounting for 59.1% and drainage benefits for 40.9%. It provides a comprehensive tool to assess long‐term project value, supporting investment decisions and improving benefit assessment systems for disaster risk reduction in levee projects.