丹江口水库运行后下游河道冲刷特性分析

Scouring Characteristics of Downstream Channel after Operation of Danjiangkou Reservoir

丹江口水库的修建改变了原来的来水来沙特性,对水库下游河床造成了不同程度的冲刷。加高后的丹江口大坝为南水北调中线水源工程。工程运用后必将对丹江口水库大坝下游河床、水资源供给及生态环境等方面都将产生影响,为了与工程运用后作一对比,2005年对丹江口水库坝下游丹江口至碾盘山河段进行了一次1/10 000水道地形测量。从历年观测资料看,从丹江口至碾盘山河段即汉江中游各河段河床出现了大量的、不同程序的冲刷,经分析计算得出,坝下游河段冲刷强度随时间及距坝里程的不同而发生变化,并且与来水量密切相关。

The running of Danjiangkou Reservoir has changed the characteristics of original water-sediment condition of Hanjiang River, the downstream river-bed of the reservoir has been caused scouring. The enhanced Danjiangkou Dam is the water-source project of the mid-route of South-North Water Transfer Project. The water in the reservoir over the spillway crest will result in very high velocity, and thus affect downstream riverbed, water resources supply and eco-environment after the project operation. In order to contrast with the project operated, a river channel geomorphologic map with a scale of 1 ： 10 000 from Danjiangkou to Nianpanshan of the dam downstream reaches was made in 2005. From the information over the years, there occurred great amount scouring to different extents from Danjiangkou to Nianpanshan. The calculated result indicates that the scouring intensity changes with time and distance from the dam-site and is related to the inflow rate.