三峡水库下游分汊河道滩槽调整及其对水文过程的响应  

Responses of riverbed morphology to the hydrological regime in anabranching reaches of the downstream Three Gorges Reservoir

作　　者：韩剑桥[1,2] 张为 袁晶[3] 赵瑾琼 HAN Jianqiao;ZHANG Wei;YUAN Jing;ZHAO Jinqiong(Institute of Soil and Water Conservation, Northwest A＆F University, Yangling 712100, China;Wuhan University, Wuhan 430072, China;Bureau of Hydrology, Changfiang Water Resources Commission, Wuhan 430010, China;Institute of River, Changjiang River Scientific Research Institute, Wuhan 430010, China)

机构地区：[1]西北农林科技大学水土保持研究所,陕西杨凌712100 [2]武汉大学水利水电学院,湖北武汉430072 [3]长江水利委员会水文局,湖北武汉430010 [4]长江科学院,湖北武汉430010

出　　处：《水科学进展》2018年第2期186-195,共10页Advances in Water Science

基　　金：国家自然科学基金资助项目(51779184);陕西省自然科学基础研究计划资助项目(2017JQ4011)~~

摘　　要：为探究大型水利枢纽影响下分汊河道演变特征及其驱动机制,根据三峡水库下游的实测水文和地形资料,基于动态分流比对分汊河道进行了类别划分,在此基础上研究了主汊、支汊与洲头心滩的调整规律及其对水文过程的响应。结果表明:(1)三峡水库蓄水后,坝下游分汊河道的洲头低滩均呈现萎缩,而汊河则表现为"主长支消"和"主消支长"并存的分异性规律;(2)基于动态分流比的分汊河道类别划分方法,上述演变差异可归纳为枯水倾向汊河发展速率大于洪水倾向汊河的规律,且2008年之后洪水倾向汊河基本表现为淤积特征;(3)水文过程中洪水削减、中水持续时间增长是滩槽调整的驱动因素,汊河冲淤均是向着主支汊格局更加稳定的方向进行,并与流量变差系数减小的水文过程相适应。To explore the evolvement characteristics and driving mechanism of a anabranching river channel under the influence of a water control project,this study classifies the branching river channel on the basis of the dynamic split ratio and measured hydrology and topography data for the lower reach of the Three Gorges Reservoir. The regulation rules of the primary branching river channel,secondary branching river channel,and low river island and their effects on the hydrological process are also investigated. The results reveal the following points. First,when the Three Gorges Reservoir is impounding,the low river island of the anabranching river channel shrinks. The branching river channel shows the specific rule of coexistence of ＂primary branching river channel goes up and secondary branching river channel goes down＂and ＂primary branching river channel goes down and secondary branching river channel goes up.＂Second,on the basis of the dynamic split ratio of the classification of the branching river channel,these evolutionary differences are summarized as follows： the development rate of the dry-water-prone branching river channel is greater than that of the flood-prone branching river channel,and the flood-prone branching river channel has basically been characterized by siltation since 2008. Third,the decrease in flood and the continuous increase in the medium flow are the driving factors for the adjustment of channel. The erosion and sedimentation of the branching river channel show a stable pattern of the primary and secondary branching river channels,which is compatible with the hydrological process of decreasing the coefficient of runoff variation.

关 键 词：分汊河道 滩槽调整 水文过程 三峡水库 长江中游 

分 类 号：TV147[水利工程—水力学及河流动力学]