太湖流域超标洪水应急调度效益评估

Benefit evaluation of emergency dispatching for over-standard flood in Taihu Lake Basin

太湖流域水利工程众多、调度复杂,科学评估水利工程洪水调度减灾效益对流域制定工程方案、预案具有重要意义。采用太湖流域洪涝淹没仿真模型及太湖流域洪灾损失评估模型,可模拟不同情景下的流域河网水位、水量及洪水淹没情况,并根据洪水淹没特征分布,评估不同水工程调度后的洪灾损失。以太湖流域发生2020年超标洪水为背景,分别模拟了采用常规调度方案和应急调度方案两种情景下太湖流域洪涝灾害情况,评估了采用超标洪水应急调度方案在2020年洪水防御中发挥的减灾效益。结果表明:采用超标洪水应急调度方案在发挥水利工程减灾效益方面作用明显,尤其是可提高太浦河、望虞河两条太湖主要泄洪河道的排水能力,可降低太湖水位0.31 m,缩短高水位持续时间1~22 d,减少淹没面积180.1 km^(2),减少流域直接经济损失约16.2亿元。研究成果可为太湖流域洪水调度方案、预案制定工作提供参考。

There are many water conservancy projects in Taihu Lake Basin and these projects′operation is complex.It is of great significance to study how to scientifically evaluate the benefits of flood control and disaster mitigation of water conservancy projects and to formulate engineering plans for river basins.In this study,we integrated a flood inundation simulation model and a flood loss assessment model of Taihu Lake Basin,which can simulate the water level,water quantity,and flood inundation of the river network in the basin under different scenarios.The models can also be used to evaluate the flood loss after the dispatch of different water projects according to the distribution of flood inundation characteristics.Based on the over-standard flood in Taihu Lake Basin in 2020,we simulated the flood disaster situation under the two scenarios of conventional dispatch plan and emergency dispatch plan,and evaluated the disaster mitigation benefits of using the over-standard flood emergency dispatch scheme in flood defense in 2020.The results showed that the use of the over-standard flood emergency dispatch scheme played an important role in defending Taihu Lake over-standard flood in 2020.In particular,increasing the drainage capacity of the two main flood discharge channels of Taipu River and Wangyu River can reduce the water level of Taihu Lake by 0.31 m,shorten the duration of high water level in Taihu Lake and adjacent area by 1~22 days,reduce the inundation area by 180.1 km^(2),and reduce the direct economic loss of the basin by about 1.62 billion Yuan.The research results can provide a reference for the formulation of flood dispatch schemes and plans in Taihu Lake Basin.