Urban flood risk assessment based on game theory-based combination weighting method

Abstract

[Objective] Flood risk assessment is crucial for developing regional disaster prevention and mitigation systems. However, current research focuses mainly on large-scale areas such as counties and cities, with limited attention to small-scale urban districts. The aim is to effectively assess urban flood risk and enhance the refinement level of risk assessment.[Methods] A flood risk assessment method suitable for urban areas was established by integrating the MIKEFLOOD hydrodynamic modeling technique with a game theory-based combination weighting model. Taking the urban area of Dexing City as an example, multi-source data were collected, including rainfall and runoff process from 12:00 on June 18 to 12:00 on June 23, 2022, a high-resolution digital elevation model(DEM) of the urban area obtained from UAV aerial photography, and measured river cross-sections. A MIKEFLOOD hydrodynamic model for the Dexing urban area was then constructed for flood simulation. After validating the model, four hazard indicators were selected based on the flood simulation result: maximum inundation depth, maximum inundation duration, maximum inundation area, and maximum inundation flow velocity. These were combined with indicators of environmental vulnerability and disaster-bearing body exposure to establish an urban flood disaster risk assessment system. To address the indicator weighting problem within the assessment system, game theory was innovatively introduced to effectively integrate subjective experience with objective data information, thereby overcoming the limitations of single weighting method. This enabled systematic analysis of the flood disaster risk indicators and effective assessment of flood disaster risk in the Dexing urban area.[Results] The result showed that there were 22 communities in the Dexing urban area, among which 13 were classified as high-risk, including Xinyingyi Village(high-risk area of 0.115 km²), Shangzhou Community(0.067 km²), Tianmenshan Community(0.034 km²), Suihanshan Community(0.024 km²), Jishui Community(0.020 km²), Shuilvqiao Community(0.019 km²), Yinshan Community(0.013 km²), Nanmen Community(0.012 km²), Kentangshan Community(0.011 km²), Yinquan Community(0.011 km²), Wuyuan Community(0.009 km²), Shengliting Community(0.004 km²), and Wuanlu Community(0.002 km²).[Conclusion] The result indicate that the MIKEFLOOD model demonstrates good accuracy and reliability in urban flood simulation, effectively revealing the spatial distribution characteristics of flood in urban areas. The high-precision DEM obtained via UAV aerial photography is crucial for urban flood risk assessment, as it not only provides accurate topographic information for the MIKEFLOOD model but also offers a reliable basis for environmental vulnerability analysis. For small-scale urban areas, UAV aerial surveying should be used to obtain elevation data. Significant differences are observed between the weights calculated by the entropy weight method and the analytic hierarchy process, making it difficult to achieve effective balance through subjective judgment alone. In contrast, the game theory-based combination weighting method, based on mathematical principles, integrates the result of these two weighting method to achieve a more scientific and rational weight allocation, providing important reference value for weight determination in comprehensive assessment. The flood risk assessment result for the Dexing urban area provide a reliable decision-making basis for the precise prevention of flood disasters and for risk classification and control in the future. Additionally, they can serve as a theoretical and method ological reference for flood prevention and mitigation efforts in similar regions.

Keywords

hydrodynamic model / flood disaster / game theory-based combination weighting / urban flood risk assessment / MIKEFLOOD / urban flooding / risk classification and prevention / precipitation