典型降雨情景下北京市十渡镇山洪灾害风险评估

Flash Flood Risk Assessment in Shidu,Beijing under the Typical Rainfall Scenario

基于北京市十渡镇“7.21”特大暴雨山洪事件淹没特征展开模拟,获得了适用于研究区的水文水动力模型参数,进而模拟了研究区20 a、50 a、100 a一遇降雨情景下的山洪危险性特征,并根据灾损模型计算了相应情景下的山洪灾害经济损失。结果显示50 a一遇降雨情景下的淹没范围比20 a一遇增加了2.2 km^(2),并且由于受河道排水能力影响,100 a一遇与50 a一遇淹没范围相似,主要增加的淹没深度区间为0.5~1.5 m。经济损失主要位于河道两侧,20 a、50 a、100 a一遇情景下经济损失分别为14.69亿元、18.16亿元以及20.40亿元。淹没特征模拟值与历史实际值具有较强相关性。情景风险评估结果可为类似十渡镇的山地旅游小镇防洪减灾提供参考依据。

In the context of climate change,the increase of extreme rainfall events and the frequent occurrence of flash floods will seriously affect the safety of people and property and sustainable socio-economic development.In this study,based on the inundation characteristics of the 7.21 flash flood event in Shidu,Beijing,the hydrodynamic model parameters applicable to the study area are obtained,and the flash flood hazard characteristics under the rainfall scenarios of 20 a,50 a and 100 a are simulated in the study area.The results show that the inundation extent under the 50a rainfall scenario increased by 2.2 km^(2) compared to the 20a rainfall scenario,and that the inundation extent under the 100a scenario is similar to that under the 50a scenario,with the main increase in depth of inundation ranging from 0.5 to 1.5 m,due to the drainage capacity of the river.Economic losses were mainly located on both sides of the river,the 20a,50a and 100a economic losses were 14.69 billion yuan,18.16 billion yuan,and 20.40 billion yuan.The simulated values of inundation characteristics have strong correlation with the actual historical values.The scenario risk assessment results can provide a reference basis for flood prevention and mitigation in mountain tourism towns similar to Shidu.