台风暴雨影响区溃坝洪灾淹没损失评估

东南沿海地区受台风暴雨影响易发生山洪、诱发水库溃坝,且水库下游区域往往地势低洼开阔,易积水而出现大面积内涝,对溃坝洪水演进产生一定影响.采用能够考虑下游初始淹没水深的二维洪水演进模型计算溃坝洪水过程,阐述了溃坝洪水数值计算方法、洪水淹没损失分类及损失率确定方法,建立溃坝洪灾淹没损失评估模型.以戍浦江流域为例,确定溃坝洪灾损失率与淹没水深等级关系,对淹没区进行溃坝洪灾淹没损失评估.计算结果表明:水库一旦发生溃坝,洪灾将造成83亿元经济损失,下游社会和生态环境遭到严重破坏,采取有效的预警措施能够显著减少下游的人员伤亡及经济损失.通过溃坝灾害评估,有助于提高水库安全管理水平,为制定防洪避险预案提供支持.

Dam-break flood loss assessment in hurricane-prone regions

The southeastern coastal areas of China are often attacked by hurricanes,and the resulting flash flood increases the risk of dam breaking.Moreover,the downstream areas of the reservoirs are often low-lying and easily flooded,which may affect the dam-break flood routing.Considering the initial water depth in the downstream areas,a two-dimensional dam-break flood model was proposed.The numerical computation method,classification of flood damage and method for determining the loss rates were discussed,and a dam-break flood loss assessment model was set up.The model was applied to evaluate the dam-break flood damage in Xupu River basin based on the determination of the relations between the loss rates and the submergence level.The result shows that the dam-break flood may cause 8.3 billion pecuniary loss and serious social and ecological environment damage to the reservoir downstream areas.If an effective precaution is launched,the casualty and pecuniary loss can be reduced significantly.The dam-break flood loss assessment not only helps improve the reservoir safety management,but also makes foundations for flood control and hedging plan.