Evaluation Of Rainstorm Distribution And Rainstorm Flood Disaster Risk In Xuancheng City

Xuancheng City is a key area of Anhui province in flood prevention, so the study of the space-time distribution of rainstorm and rainstorm flood disaster risk assessment are practically significant to the protection of people’s life and property safety and the work of disaster prevention and mitigation.17 rainfall stations of Xuancheng City were selected to get the daily precipitation data from 1970 to 2013 for analyzing in this study. The arithmetic average method is used to get rainstorm days, the average rainfall of rainstorms, maximum rainfall and other hydrological parameters, and line chart is depicted to obtain the trends of rainstorm parameters. The period and frequency of the rainstorm days of Xuancheng City are obtained by Morlet wavelet analysis. Dangerous hazard -formative factors, subsequently environmental sensitivity, the vulnerability of hazard-affected bodies, disaster prevention and mitigation capacity and their 13 specific indicators were selected as the basic indicators to acquire the weight of each index of rainstorm flood risk by the analytic hierarchy process (AHP), and then the normalized index of each specific value is multiplied by the corresponding weight. Finally we get the composite indicting map of Xuancheng City’s rainstorm flood disaster risk with ArcGIS software, and put forward rainstorm flood risk prevention measures aiming at Xuancheng City from the aspects of engineering measures and non-engineering measures.The results show that the inter-annual change in rainfall fluctuates greatly in Xuancheng City, with the declining trend of fluctuations overall. The average rainfall is 1372.45 mm/year, significantly different across years in different areas, and it is bigger in the southern mountainous area than that of the northern plains. There are three periodical oscillation signal,5-years,14-years and 27-years of rainfall, and three characteristic time scales,5-years,12-years and 26-years of rainstorm days in Xuancheng City. The high risk areas of rainstorm in Xuancheng City mainly distributes in the south, including Jingxian County, Jingde County, Ningguo City, Xuanzhou District and south of Guangde Area, and rainstorm flood disaster risk diminishes gradually from south to north.This study researches on the rainstorm of Xuancheng City from the aspects of space-time distribution and risk of rainstorm floods, in order to provide basis for the local flood control and disaster mitigation and guarantee for the local economic construction and people’s life and property safety.