浅论长江中游洪灾高危险性

Introduction to the high danger of flood disaster in the middle Yangtze River

通过对长江洪水的致灾性、河道边界条件及其孕灾性、承载体易损性的分析,论述了长江中游为我国洪灾高危险区的必然性。分析了人类对河流的治理,使河道稳定性增加,减少了洪灾的风险,但是长江中游的局部河段却发生洪水位增高的趋势,又增加了洪灾风险,该区域高危险的基本特性犹存。研究了三峡运行后,长江中下游出现新的防洪形势:一方面三峡水库巨大的防洪库容拦蓄洪水,大大减少了中下游的洪灾,另一方面因河道的强冲刷,使河势变化剧烈、横向摆动增强,局部河段岸壁失稳,又增加防洪压力。同时因总体水面比降趋平,洪灾风险有向下游转移的趋势。未来长江中游仍为洪灾高危险区,仍应给予高度重视。

Through the analyses of the formation factors causing disaster of the Yangtze River flood, the boundary conditions and its disaster-breeding environment and the carrying body easy to be damaged, this paper devotes to the inevitability of the middle Yangtze River becoming the extreme seriousness of flood disaster in China, analyzes the harnessing of human creature along the river to increase the stability of the river course, thus reducing the risk of flood disaster. But, the tendency of raising the flood stage still exists in the local reaches of the middle Yangtze River, which also increase the dangers of flood disaster and is still the high dangerous basic characteristics in this region. After studying the operation of the Three Gorges Project, new situation of flood protection occurs in the middle Yangtze River.On the one hand, a huge flood control capacity of the Three Gorges Reservoir can retain a large amount of floodwaters, thus greatly reducing the flood disaster in the middle and lower of the Yangtze River.On the other hand, the strong erosion of the river course will make the river regime to change violently, increasing river channel shifting.It is difficult to stabilize bank wall of the local reaches, which also increases the pressure of flood protection. Meanwhile, because of flattening surface slope, there is a tendency to transfer downstream at the risk of flood disaster. In the future, the middle Yangtze River is still the high dangerous region, and it should still be attached great importance to.