Flood Routing Models in Confluent and Dividing Channels
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摘要: 通过引入水深连接方程，耦合了干、支流河道的水流运动，给出了它们的流量分配关系，建立了交汇、分流河道洪水演进模型．对交汇河道中水流顶托作用随河道参数的变化规律进行了研究．分析了干、支流洪峰遭遇现象，指出干流和支流的洪峰遭遇是1998年长江大洪水干流高洪水位的重要原因之一．并定性解释长江干流荆江河段的裁弯取直和长江分流河道的淤积对河道水流的影响．Abstract: By introducing a water depth connecting formula,the hydraulic equations in the dividing channel system were coupled and the relation of discharge distribution between the branches of the dividing channels can be yielded.In this manner,a numerical model for the confluent channels was established to study the variation of backwater effects with the parameters in the channel junction.The meeting of flood peaks in the mainstream and tributary can be analyzed with this model.The flood peak meeting is found to be a major factor for the extremely high water level in the mainstream during the 1998 Yangtze River flood'subsequently the variations of discharge distribution and water level with channel parameters between each branch in this system were studied as well.As a result,flood evolution caused by Jingjiang River shortcut and sediment deposition in the entrance of dividing channels of the Yangtze River may be qualitatively elucidated.It is suggested to be an effective measure for flood mitigation to enhance regulation capability of reservoirs available upstream of the tributaries and harness branch entrance channels.
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Key words:
- confluent channels /
- dividing channels /
- backwater effect /
- flood peak meeting /
- the Yangtze River
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