Presenter
Mr. Dongsheng WANG, Yunnan Provincial Bureau of Hydrology and Water Resources
Co-author(s)
Mr. Bogen LI, Yunnan Provincial Bureau of Hydrology and Water Resources
Sub-theme
1. Water-Human-Economy(Agriculture, Industry, City...)-Ecology Nexus under a Changing Environment
Topic
1-4. Water security challenges in key regions
Body
In the context of climate change and urbanization, the frequent occurrence and serious impact of urban storm floods and waterlogging are the current research hotspots, and are also important measures to implement the people-centered idea of disaster prevention and mitigation. In this paper, a long series of rainstorm monitoring data of more than 30 years from 15 urban rainfall representative stations in Yunnan Province are collected, uses the methods of trend analysis, comparative analysis, comprehensive index, Mann-Kendall test and P Ⅲ Hydrological frequency analysis,to quantitatively analyze the characteristics and evolution rules of the extreme value, frequency, season and other characteristics of the long rainstorm in different periods of 10 min, 1 hour, 6 hours, 24 hours, in 9 typical cities of different scales such as 1 provincial capital, 6 municipal-level and 2 county-level in Yunnan Province. Main conclusions:(1) The rainstorm intensity in Kunming, Lufeng, Wenshan and Mangshi has an obvious increasing trend, the frequency of occurrence in Kunming and Wenshan has an increasing trend, the probability of occurrence in Mangshi and Wenshan in dry season has increased,the occurrence time of Kunming and Lufeng is more concentrated in June and August. But the change trend failed the 5% confidence test.(2) With the pace of urban construction, the location of the extreme rainstorm in Kunming experienced the evolution process from north to south to north.(3) Through comparative analysis, when the area of urban built-up area is greater than 40Km2, the impact of urbanization on rainstorm begins to appear, and increases with the increase of urban scale. For example, the rainstorm extreme value in the central urban area of Kunming with the most obvious impact in 2011-2020 increased by 21-31.8% on average compared with that in the suburbs, and the frequency increased by 15-25%. However, this change has not yet had a significant impact on the P Ⅲ hydrological frequency analysis results of rainstorm in different periods at the representative station.(4) Countermeasures and suggestions: control the scale of large cities and promote the development of small and medium-sized cities, improve the design standards of urban flood control and drainage, take engineering and non-engineering measures to enhance the flood regulation capacity of storm flood in the upper reaches of the city,Strengthen the utilization of urban storm flood resources.