摘要
深泓线演变规律对于研究河势与河床地貌的变化具有重要意义。为探明三峡水库蓄水后水沙条件改变对下游城陵矶-汉口河段(城汉河段)深泓线演变的影响,基于1998~2017年城汉河段实测深泓线高程资料,对比分析了此期间深泓线高程和空间分布模式的变化,及其与水沙条件的关系。结果表明:三峡水库蓄水前深泓线总体上冲淤平衡,蓄水后的2003~2008年间河道深泓线剧烈冲刷下切,2008年后冲刷态势有所放缓,且不同高程深泓点分布的多样性增大;蓄水后深泓线的冲刷下切也导致与之相关的聚集性地貌单元的平均间距由30 km左右大幅缩短为20 km;河道水沙条件对深泓线演变相对贡献率高达88.9%,三峡水库蓄水引起的河道汛期水流冲刷强度增大是引起深泓冲刷下切的最主要原因。
The thalweg variation is of great significance to studing the evolution of river regime and riverbed geomorphology.To explore the influence of the water-sediment variation caused by Three Gorges Reservoir impoundment on the thalweg evolution in the Chenglingji-Hankou reach of the Changjiang River,the changes of the elevation and spatial distribution pattern of the thalweg and their relationship with water-sediment conditions were analyzed based on the measured elevation data of the thalweg from 1998 to 2017 in the Chenglingji-Hankou reach.The results showed that the thalweg was generally in the equilibrium state of scouring and silting before the impoundment of the Three Gorges Reservoir,while the thalweg was severely scoured during 2003 to 2008.After 2008,the scouring trend slowed down,and the diversity of the thalweg point distribution at different elevations increased.Moreover,the average distance between the aggregated geomorphic units was shortened from about 30 km to 20 km due to the thalweg scouring after reservoir impoundment.The erosion intensity increasing during flood season caused by Three Gorges Reservoir impoundment was the main reason for the great thalweg scouring in the Chenglingji-Hankou reach,with a relative contribution rate of 88.9%.
作者
李咏梅
孙治国
贾方方
LI Yongmei;SUN Zhiguo;JIA Fangfang(Sichuan Water Conservancy Vocational College,Chengdu 611231,China;Key Laboratory of River and Lake Control and Flood Control of Ministry of Water Resources,Changjiang River Scientific Research Institute,Wuhan 430010,China;College of Water Conservancy and Environment,China Three Gorges University,Yichang 443002,China)
出处
《人民长江》
北大核心
2022年第8期9-14,共6页
Yangtze River
基金
国家自然科学基金项目(51779014)。
关键词
深泓线
水沙异变
城陵矶-汉口河段
地貌单元
三峡水库
长江
thalweg
water-sediment variation
Chenglingji-Hankou reach
geomorphic unit
Three Gorges Reservoir
Changjiang River
