Small Watersheds Based on Game Theory Comprehensive Weight Method Flash Flood Disaster Risk Assessment

In order to accurately assess the risk of flash flood disasters in small-scale river basins, this paper takes the small watershed of Beidasha River in Shandong Province as an example, selects 10 influencing indicators in view of the single method of flash flood disaster risk assessment in the past and the one-sided shortcomings of determining the weight coefficient of indicators, synthesizes the analytic hierarchy method and entropy method based on the principle of game theory, determines the more scientific index weight value, introduces the fuzzy comprehensive analysis method, constructs a flash flood disaster risk assessment model in the small watershed, and uses ArcGIS to divide the risk area. Combined with the township zoning and administrative village point layers, the raster was used as the evaluation unit to analyze the risk of flash flood disaster in the whole river basin. The results show that the annual rainstorm days are the most weighted among the indicators, followed by the topography index, and the vegetation index has the lowest weight. The area with high risk level accounted for 40.52% of the whole river basin, which was mainly distributed in the lower reaches of the river basin, and the evaluation results were consistent with the distribution of historical disasters, which could provide data support for flash flood disaster early warning.