黄河北干流河段桃汛洪水演进特征分析

Analysis of Spring Flood Evolution Characteristics in the North Main Reach of Yellow River

为研究桃汛洪水在黄河北干流演进过程及对潼关高程的影响,根据北干流河段沿程水文站实测资料,统计分析了桃汛洪水水沙特征值的沿程变化。结果表明,桃汛期的洪峰、沙峰、洪量和沙量从头道拐到潼关总体增加,洪峰和沙峰的区间变化受水库运用影响较大;洪峰经天桥水库增值较大,之后到潼关沿程逐渐衰减、洪水过程坦化;天桥水库排沙产生比较高的瞬时含沙量,多次超过100 kg/m^(3),但沿程迅速衰减坦化,洪水期沙量仍表现为沿程增加;万家寨水库运用初期削减洪峰、洪量减少,直接影响潼关的洪水过程,桃汛试验后潼关洪峰和洪量增加。因此,建议桃汛期万家寨等水库的调度需要继续保持一定的出库流量指标,同时水库可以进行适当排沙,发挥桃汛洪水对河道的有利作用。

The characteristic values of water and sediment in spring flood season is statistically analyzed according to the measured data of hydrological stations,as well as the evolution process and influence factors of the flood in the North main stream of Yellow River.The results show that flood peaks,sediment peaks,runoff and sediment volume generally increase from Toudaoguai to Tongguan during the spring flood;the flood peak values increase through Tianqiao reservoir,and then gradually decrease along the way to Tongguan.Tianqiao reservoir produced high instantaneous sediment concentration,which was more than 100 kg/m^(3) for many times,but it rapidly decreased along the river,and the sediment volume still increased.The flood peak and runoff in Tongguan reduced at the early stage of Wanjiazhai reservoir operation,its increased after the experiment of spring flood.Therefore,it is suggested that the operation of Wanjiazhai reservoir should continue to maintain a certain discharge during spring flood,and at the same time,the reservoir can be properly desilting to play a beneficial role of spring.