黄河口清水沟流路水沙变化与河道演变响应

Variation of flow and sediment and evolution response in the Qingshuigou channel of the Yellow River Estuary

采用实测资料分析的方法,研究了水沙变化条件下黄河口清水沟流路河道演变的复杂响应过程。研究结果表明:1986年以后,黄河口清水沟流路水沙减少,河道萎缩,过流能力减小,断面形态宽浅;2000年以后,小浪底水库蓄水拦沙运用,黄河口水沙关系明显改善,河道萎缩有所恢复,过流能力增大,断面形态趋于窄深,黄河口河道演变与水沙过程有着良好的响应关系,河道过流能力随汛期5年滑动平均水量的增大而增大,随汛期5年滑动平均来沙系数的增大而减小。未来应通过上中游水库群的联合水沙调控运用,持续调控出5年以上水沙关系协调的下游水沙过程,这样对黄河口河道冲刷能产生良好的效果。

Using the method of data analyses,the complex response processes of river evolution in the Qingshuiguo channel of the Yellow River Estuary(YRE)are studied under the conditions of flow and sediment variation.The results show that:After 1986,the flow and sediment into YRE decreased,the river channel shrank and its flow capacity reduced,the section configuration became wide and shallow.With the operation of water storage and sediment control in Xiaolangdi Reservoir after 2000,the relationship between flow and sediment has been improved significantly,the shrinkage of the channel has been recovered somewhat,the flow capacity increases and the section configuration tends to be narrow and deep.It is also found that the channel evolution in YRE is in good response to the incoming flow and sediment.The flow capacity increases with the increase of 5-year moving average flow and decreases with the increase of 5-year moving average sediment coefficient during the flood season.In the future,joint water and sediment regulation of upstream and midstream reservoirs should be carried out to continuously regulate downstream coordinated water and sediment processes for more than 5 years,which can have a good effect on channel erosion in the Yellow River Estuary.