洞庭湖区退田还湖的洪水效应模拟

洞庭湖多年平均削减入湖洪峰流量约10000m3/s,这对于保护长江中下游,特别是中游地区的防洪安全十分重要.但由于泥沙的严重淤积,以及湖泊湿地被大规模垦殖,使洞庭湖的调蓄功能下降,江湖洪水威胁加剧.1998年长江流域发生特大洪涝灾害,中央及时提出了"退田还湖、平垸行洪"等长江流域洪水治理的32字指导原则,洞庭湖区是实施该原则的重点地区.应用数值模拟方法,通过建立洞庭湖与长江耦合的水动力学数值模型,针对1998年洪水,模拟研究了洞庭湖区退田还湖的洪水效应,并设计了8种方案分别进行定量评估.结果显示,退田还湖工程的实施,对降低洞庭湖区江湖洪水位,缓解江湖洪水威胁具有重要意义.

Simulation of flood effect in Dongting Lake region by restoring lake area with stopping cultivation

Dongting lake cuts down the flow of flood peak into the lake with 10000 m~(3)/s for many years and is of great importance to prevention of floods in the middle and lower of the Yangtze River. The threat arising from floods is getting serious since 1949, because of more and more silt and large-scaled cultivation on the wetlands. The guiding principles of floods control in the Yangtze River reaches, which refers to restoring lake area with stopping cultivation, has been presented by Chinese government since the floods of 1998 and the Dongting Lake region is one of important areas to implement the above strategy. Based on hydrodynamic numerical model coupling Donging Lake with Yangtze River,the flood effect in Dongting Lake region by restoring lake area with stopping cultivation for 8 regimes aimed at flood situation in 1998 was simulated. The results show that it is of importance for lowering the water level of flood of the Dongting Lake and reducing the threat from the flood to implement the project of returning being lake from cultivating.