三峡水库蓄水后宜都水道演变及航道变化

Evolution of Yidu Reach and Variation of Waterway After Impoundment of the Three Gorges Reservoir

依据蓄水前后原型观测资料,分析了三峡工程蓄水前后宜都河段——三峡枢纽下游的低水分汊河段的河势和河床冲淤变化情况及其对航道的影响,并对该河段的演变趋势进行了预测。结果表明,来沙量减少使宜都水道冲刷,沙泓上浅区冲刷下切,而下浅区以冲滩为主,石泓深泓冲刷下降,南阳碛冲刷缩小,分流格局有发生变化的趋势。沙泓上浅区航道条件改善,但下浅区航道展宽左摆,发展下去不利于航道维护。

Based on the prototype observation data before and after the impoundment, this paper analyzes the variation of river regime, siltation and erosion of river bed, as well as the impoundment, this paper analyzes the variation of river regime, siltation and erosion of river bed, as well as the influence on channel for the river reach from Yidu to the low-water branching reach downstream the Three gorges junction after the impoundment, and forecasts the trend of evolution of the reach. The result reveales that the decrease of sediment transportation of the upper reaches results in riverbed scouring and coarsing on Yidu reach; The upper and lower shallow regions in Shahong are separately deepened and broadened, while the thalweg in Shihong is lowered, and Nanyangqi is scoured and draw back.., all the above may cause variation of the distribution pattern. The navigation condition of Shahong upper shallow region is improved, whereas channel maintenance of the lower shallow region becomes more difficult since the channel has been broadened.