西江中上游型洪水影响下龙滩水库调度特性初探

为探讨龙滩水库对西江中上游型洪水的防洪削峰作用,选取"96·7"中上游型洪水作为典型洪水,拟定4种龙滩水库调度方案,采用率定和验证后的西江中游河网及梯级水库水动力数学模型,分别对典型洪水及频率为0.2%、1%和2%水文条件下的4种梯级水库调度方案进行了模拟计算和分析。结果显示,该水动力学模型能很好地模拟洪水特性参数的时间变化规律以及水库的运行调度过程;对于"96·7"典型中上游型洪水,由于红水河洪水较小,梧州断面流量以柳江来水为主,龙滩水库调度对梧州断面削峰效果有限;但针对中上游型不同频率的大洪水,采用提前启用龙滩水库的调度方案能有效削减梧州断面的洪峰值;其中,龙滩水库采用发电流量控泄的方案可以达到防洪和发电效益的统一。

Study on dispatch characteristics of Longtan Reservoir under influence of flood in middle and upper reaches of Xijiang River

In order to analyze the flood control and peak reducing effect of Longtan Reservoir on flood in the middle and upper reaches of the Xijiang River, we proposed four dispatch schemes for Longtan Reservoir to deal with the typical flood occurred in July, 1996. By using the calibrated and verified river network of the middle reaches of Xijiang River and hydrodynamic model of cascade reservoir, we simulated the dispatch effect by the four schemes under the typical flood and 3 different frequency floods( 0.2%, 1% and 2%). The results showed that the one-dimensional river network hydrodynamic model could well simulate the time variation of flood characteristic parameters and the operation and dispatch process of the cascade reservoirs. For the typical flood, the dispatching of Longtan Reservoir has little effect on reducing the flood peak at Wuzhou section because the flux mainly came from the Liujiang River. However, for the 3 different frequency floods , the flood peak could be effectively cut if the Longtan Reservoir is put into operation earlier, while the dispatch scheme of controlling the flood by power discharge could achieve the integrated benefit of flood control and power generation.