Urban flood risk assessment based on the combination weight of game theory: a case study of Jinan City, China

Floods are one of the most common natural disasters and can occur anywhere in the world. In China, with climate change and urbanization leading to an incerase in the frequency and intensity of extreme rainfall, the damage caused by urban flooding is becoming more severe. Flood risk assessment is an important tool for flood prevention and mitigation, and has important practical applications in urban flood risk management and response. In this paper, a new multi-criteria decision analysis (MCDA) model for urban flood risk assessment was proposed, which integrates the game theoretic (GT) combination of AHP-CRITIC subjective and objective assignment methods to determine the weights of the indicators. Based on the hazard-vulnerability as the flood risk assessment system, a total of 17 representative indicator factors were selected to explore the distribution of flood risk in the main urban area of Jinan City. The results show that the very high risk zones were mainly distributed in the border area of four districts: Lixia District, Tianqiao District, Huaiyin District and Shizhong District. The collection of historical flood-prone point data to verify the assessment results shows that the GT method assigns weight values with comprehensive consideration of the impact of subjective and objective assignments, which verifies the reliability of the method, and thus the flood risk zoning maps obtained are more reasonable and reliable. The game-theoretic combination assignment method can reduce the subjectivity of a single assignment method, improve the accuracy of flood risk assessment, and provide a basis for urban flood risk management.