HEC-RAS洪水演进模型的应用

Application of HEC-RAS Flood Routing Model in the Three Gorges Reservoir

上游入库洪水在三峡库区向下游传播的过程中,受到库区的调蓄作用,洪峰削减明显。同时由于区间入流的影响,库区的调蓄作用被掩盖,这为研究洪水在库区行进中所受的调蓄作用带来了困难。应用在三峡库区建立的HEC-RAS洪水演进模型,模拟1989年-2000年间209场洪水在不考虑区间入流时向下游传播的过程,并检验洪水传播时间,其中洪水波行进时间用上下游洪水过程线的时间重心之差表示。按照库区5个水文站位置将库区分为4段分别检验。将HEC-RAS模型应用于三峡水库2006年和2007年蓄水期库区水位的模拟,结果表明,蓄水期水位变化过程得到了较好的模拟,对最高水位的模拟误差可控制在0.2 m之内。并应用该模型,分析和比较了库区4个部分对洪峰的削减作用。

During the routing process to the lower reach of the Three Gorges Reservoir, the peak of flood generated in the upper watershed of the reservoir decreased as the storage effect of the reservoir. The decrease was masked by the lateral runoff from the Three Gorges Area,which hinders the research of the storage effect that the flood received. Based on the HEC-RAS flood routing model applied in the reservoir, 209 events during 1989 to 2000 were simulated. Simulated routing time was verified with the observed and recorded routing time, in which routing time was calculated by the time moment difference between the hydrograph of the upper and lower cross section. The verification was carried out in the four parts of the mainstream, which was divided by 5 gauge stations. The model was also applied to simulate the reservoir stage during the water storage period from 2006 to 2007. The results showed that the stage process was simulated accurately, in which the highest stage error was within 0. 2 meter. The model was then applied to simulate the flood peak decreasing in the four parts of the reservoir to analysis the storage effect difference among the different reservoir parts.