黄河下游河道平滩流量与造床流量的变化过程研究

采用黄河下游各水文站1950-2003年实测资料,系统分析了过去50多年间黄河下游平滩流量和造床流量的变化过程及其与花园口来水量的响应关系,分析表明在过去50多年间黄河下游平滩流量和造床流量总体上呈逐渐减小的趋势,其数值随花园口来水量的丰枯而变化,花园口来水量大,造床流量就大,造床能力就强,塑造的主河槽的平滩流量也大。文中给出了平滩流量与造床流量的响应关系,通过造床流量和平滩流量的比较,指出黄河下游造床流量小于平滩流量,过去50多年间水流塑造河床的能力小于主河槽当时的过流能力,黄河下游主河槽萎缩是河道演变响应来水变化的必然结果。研究结果进一步表明,通过小浪底水库调整进入下游的来水过程,增大河道的造床流量,进而增大河道的过洪能力是治理河道萎缩的重要措施之一。

Change of bankfull and bed-forming discharges in the Lower Yellow River

Based on the data of the Lower Yellow River from 1950 to 2003,this paper analyzes the change processes of the bankfull and bed-forming discharges and their response relationships to the runoff of Huayuankou Station.The result shows that the bank-full and bed-forming discharges decreased slowly in the past 50 years and they varied with the runoff of Huayuankou Station.The large runoff made large bed-forming discharge and the good bed-forming ability,and therefore caused large bankfull discharge.The comparison of the bed-forming and bankfull discharge shows that the bed-forming discharge was smaller than the bankfull discharge,and the channel shrinkage in the Lower Yellow River was resulted from the change of incoming flow.The research results furtherly suggest that one of the most efficient measures to increase the flood-conveying capacity of the Lower Yellow River should be to regulate flow processes released from Xiaolangdi Reservoir.