西江中游洪峰演进特性研究

Characteristics of Flood Peak Propagations in Middle Reaches of the Xijiang River

采用率定和验证过的西江中游河网及梯级水库水动力数学模型平台,选取"06·7"典型中下游型洪水进行同倍比放大,计算和分析了西江干流红水河及支流柳江形成的不同频率洪水洪峰演进特性。结果显示,在不考虑梯级水库调度及柳江洪水时,干流洪水洪峰由天峨到达迁江站需19~22 h,到达武宣需33~38 h,到达大湟江口站需45~50 h,到达梧州站需52~60 h,洪峰量值减小比例分别为3.4%、7.0%、9.4%和10.2%;加入柳江洪水后,洪峰抵达下游各站点时间主要取决于柳江洪水,柳江洪峰先于红水河洪水抵达下游各站点,对红水河洪水造成显著顶托,致使红水河洪峰迅速坦化而消失,形成了下游的单峰型洪水特征。

The amplified flood propagations with the case study of the flood progress in July, 2006 were simulated numerically by using the whole hydro- dynamic mathematical model of river nets and cascade reservoirs of the middle reaches in Xijiang River. The propagation characteristics of flood peaks under different frequency in the main reaches of the Xijiang River with its tributary of the Liujiang River were studied. The result showed that there were about 19 ~ 22 h needed for flood peak reaching to Qianjiang station from Tian'er station, 33 ~ 38 h needed to Wuxuan station, 45 ~ 50 h needed to Dahuangjiangkou station and 52 ~ 60 h needed to Wuzhou station,with peak values reducing about 3. 4%, 7. 0%, 9. 4% and 10. 2% respectively. When floods from the tributary of the Liujiang River have been included, the time needed for peak reaching to the stations downstream of the confluence depended on the characteristics of flood from the Liujiang River. Flood peaks from the tributary of the Liujiang River would reach the stations downstream of the confluence earlier than from the Hongshui River. It also showed that floods from the Hongshui River have been jacked and smoothed by those from the tributary, leading to disappearing of flood peaks and emergence of single peak floods downstream.