Determining Economic Damage in Downstream Areas Due to Flood Discharge and Reservoir Failures Using GIS: The case of Dong Be Reservoir, Thanh Hoa province, Vietnam

Abstract

Reservoir safety is always a top priority in dam management, but when dam failures occur, leading to flooding and substantial damage to lives and property. Proactively identifying the extent and types of damage can help policymakers and regional planners minimize losses and actively prevent risks . The study was conducted in Xuan Du Commune, downstream of the Dong Be reservoir, Thanh Hoa province. The methodology employs a regional economic model with direct survey data from April 2024, collected from villages in the commune, along with a dam-break flood simulation corresponding to the inspection frequency. Direct surveys using questionnaires were conducted to estimate the damage value of various asset types and agricultural land resources, Geographical Information System (GIS) was utilized for calculations and visually represent the results on maps. The scenario was modeled to demonstrate the downstream risk level of the reservoir, as well as the flood extent based on the depth in the research area. The results show that agricultural land resources were the most affected, with the highest damage value, followed by residential land, while public infrastructure and local buildings were the least affected.