太湖流域应对特大洪水防洪工程效益模拟

防洪效益评估对防洪工程投资决策与减灾对策制定具有重要意义。建立集成了与太湖流域防洪效益评估相关的系列模型和方法，包括含降雨产流与平原净雨计算的水文分析方法、由河网水动力学模型和平原区域洪水分析模型组成的大尺度水力学模型、综合流域社会经济和淹没因素的洪灾损失评估模型。模拟了太湖流域遇特大洪水的灾害损失，开展了不同防洪工程应对流域性特大洪水减灾效益的预测分析。结果表明：1999年型200年一遇降雨将会给太湖流域造成高达568.29亿元的直接经济损失，外排动力增强30%至100%的防洪效益介于26.69亿元到45.70亿元之间，新建圩区、太浦河拓宽的防洪效益依次减小，而圩区泵排能力增加30%的防洪效益仅为0.65亿元。基于研究成果提出了增设外排泵站、加强圩区科学调度、通过保险分担风险等应对特大洪水的对策措施建议，为太湖流域特大洪水的防治提供支撑和参考。

Benefit simulation of flood control project in Taihu Lake basin under extreme floods

Flood control benefit assessment is very important for flood control project investment decision-making and disaster mitigation countermeasures. A set of integrated models and methods related to flood control benefit assessment were established and applied to the Taihu Lake basin. The set of models includes hydrological analysis methods integrating rainfall production and plain rain calculation,a large-scale hydraulic model composed of a river network hydrodynamic model and a plain regional flood analysis model,and a comprehensive damage assessment model considering the social economy and inundation factors. In this study,the flood damage of the Taihu Lake basin was simulated under extreme flood conditions. In addition,predictions of the disaster reduction benefits of different flood control projects in response to the basin-scale extreme floods were carried out. The results show that direct economic damage would be 56.829 billion RMB under the 200-year return period rainfall of the 1999 type. The flood control benefits of 30% to 100% reinforced external power would be in the range of 2.669 billion RMB and 4.570 billion RMB,followed by the benefits of new polder building and Taipu River widening. However,the benefit was merely 65 million RMB when the pump capacity of polders was increased by 30%. Based on these research results,countermeasures and suggestions,such as adding drain pumping stations along the river and the coast,strengthening the scientific dispatching of polders,and coping with risks through insurance sharing,are proposed to provide support and serve as references for extreme flood prevention in the Taihu Lake basin.