Abstract:

In this paper, we employed a combination of subjective and objective weighting methods, together with the game theory, to assess flash flood risk in the Jialing River Basin. Results indicate that the flood risk distributions derived from four objective weighting methods are generally consistent, although the proportion of risk levels varies slightly among the methods. Specifically, the CRITIC weighting method identifies more high-risk areas. Therefore, we integrated the CRITIC weighting method, hierarchical analysis, and the game theory to develop a combined weighting assessment, and obtained the comprehensive spatial distribution of flash flood risk in the Jialing River Basin. Overall, flash flood risk exhibits an increasing trend from the northwest to the southeast, with high-risk areas primarily concentrated in the Sichuan Basin and its periphery, encompassing 22 counties and districts in Sichuan and Chongqing. Low-risk areas are predominantly found in the hilly regions of the northwest. Among the factors influencing flash flood risk, mean annual rainfall and runoff depth contribute most significantly, followed by socio-economic factors such as population density and GDP(Gross Domestic Product). Sub-surface conditions, including slope and topographic relief, contribute the least. The findings of this study will serve as a crucial reference for flash flood management and response in the upper Yangtze River Basin, including the Jialing River Basin.

Key words: flash flood, risk assessment, subjective and objective weighting method, game theory, Jialing River Basin