不同重现期下新疆典型水库流域暴雨山洪灾害风险评估-以哈密市峡沟水库流域为例

Risk Assessment of Heavy Rainfall and Flash Flood Disasters in Typical Reservoir Basins of Xinjiang under Different Return Periods: A Case Study of the Xigou Reservoir Basin in Hami City

摘要:

暴雨山洪灾害对人民生命财产安全和社会经济发展构成严重威胁。本研究以哈密市伊吾县峡沟水库流域为研究对象，基于1961-2023年历史降水资料，采用FloodArea模型和重现期函数估算不同重现期下极端降水事件的面雨量，并模拟山洪淹没风险。结果显示，1961年至2023年，峡沟流域日最大降水量显著上升，平均每十年增加2.1mm，20世纪80年代末以来趋势尤为明显。2018年7月31日哈密市山区特大暴雨过程中，降水量在6:00左右达到峰值，地表径流迅速形成，淹没范围和深度显著扩大。通过SPSS和MuDFiT工具确定，100年一遇、50年一遇、30年一遇、20年一遇、10年一遇和5年一遇的面雨量分别为51.83mm、34.94mm、26.23mm、20.62mm、13.70mm和8.93mm。模拟结果显示，随重现期增加，淹没范围和深度显著扩大，30年及以上的面雨量达新疆暴雨等级。承灾体易损性评估显示，易损性随洪水重现期的增加而显著上升，100年一遇的洪水在淹没深度超过1.8米时，受影响人口和GDP比例分别高达60.87%和54.03%。这些结果表明严重洪水对社会和经济的影响深远，需要采取更为严格的防灾减灾措施。

Abstract:

Heavy rainfall and flash floods pose severe threats to people’s lives, property, and social and economic development. This study focuses on the Xigou reservoir basin in Yiwu County, Hami City, using historical precipitation data from 1961 to 2023. The FloodArea model and return period functions were employed to estimate the areal rainfall of extreme precipitation events under different return periods and to simulate flood inundation risks. The results show that the maximum daily precipitation in the Xigou basin has significantly increased from 1961 to 2023, with an average increase of 2.1 mm per decade, especially evident since the late 1980s. During the major rainfall event in the Hami mountainous area on July 31, 2018, the precipitation peaked around 6:00 AM, leading to rapid surface runoff and a significant expansion of the inundation range and depth. Using SPSS and MuDFiT tools, the areal rainfall for return periods of 100, 50, 30, 20, 10, and 5 years were determined to be 51.83 mm, 34.94 mm, 26.23 mm, 20.62 mm, 13.70 mm, and 8.93 mm, respectively. The simulation results indicate that the inundation range and depth increase significantly with the return period, and the areal rainfall for 30 years or more reaches the heavy rainfall standard of Xinjiang. The vulnerability assessment of disaster-bearing bodies shows that vulnerability increases significantly with the increase in flood return period. For a 100-year flood with a inundation depth exceeding 1.8 meters, the affected population and GDP proportions are as high as 60.87% and 54.03%, respectively. These findings highlight the far-reaching impact of severe floods on society and the economy, emphasizing the need for more stringent disaster prevention and mitigation measures.