| 长江中游荆江河段同流量-水位演化特征及驱动成因 |
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| 引用本文： | 柴元方,邓金运,杨云平,孙昭华,李义天,朱玲玲.长江中游荆江河段同流量-水位演化特征及驱动成因[J].地理学报,2021,76(1):101-113. |
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| 作者姓名： | 柴元方 邓金运 杨云平 孙昭华 李义天 朱玲玲 |
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| 作者单位： | 武汉大学水资源与水电工程科学国家重点实验室,武汉430072;长江水利委员会长江科学院,武汉430010;武汉大学水资源与水电工程科学国家重点实验室,武汉430072;长江水利委员会长江科学院,武汉430010;交通运输部天津水运工程科学研究所工程泥沙交通运输行业重点实验室,天津300456;长江水利委员会长江科学院,武汉430010;长江水利委员会水文局,武汉430010 |
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| 基金项目： | 国家重点研发计划(2018YFB1600400);长江科学院水利部江湖治理与防洪重点实验室开放基金项目(CKWV2018463/KY,CKWV2019727/KY,CKWV2017502/KY);国家自然科学基金项目(51979132)。 |
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| 摘 要： | 水库运行改变了坝下游水沙输移条件,在河道冲刷的同时,引起水位过程出现适应性调整。本文以长江中游荆江河段为对象,采用多项式拟合法,对比分析1991—2016年间分级流量—水位变化特征,采用基于河流动力学原理的分离变量法,识别河道冲淤、下游控制水位及河床综合糙率等变化对分级流量—水位变化的影响程度。研究表明：1991—2016年间,长江中游荆江河段同流量—枯水位呈下降趋势,2009年以来降幅增大;河道冲刷是引起同流量—枯水位下降的主控因素,河床综合糙率增加抑制了同流量—枯水位下降起到积极作用。1991—2016年间,荆江河段同流量—洪水位经历了先减小后增大的“凹”线型变化,2003年以前洪水特征为“高洪水流量—高水位”,2009年以来逐渐演化为“中大洪水流量—高水位”,同流量—洪水位特性发生转变;河床综合糙率增大是同流量—洪水位抬升的主控因素,河道冲刷抑制了同流量—洪水位的抬升态势。在航道条件及防洪情势上,应重点防控近坝段沙质河段冲刷引起的水位下降溯源传递作用,其洪水流量—水位特性的转变,不利于减缓荆江河段的防洪压力。
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| 关 键 词： | 同流量-水位 时空演化 河道形态 长江中游 |
| 收稿时间： | 2019-07-29 |
| 修稿时间： | 2020-12-05 |
Evolution characteristics and driving factors of the water level at the same discharge in the Jingjiang reach of Yangtze River |
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| CHAI Yuanfang,DENG Jinyun,YANG Yunping,SUN Zhaohua,LI Yitian,ZHU Lingling.Evolution characteristics and driving factors of the water level at the same discharge in the Jingjiang reach of Yangtze River[J].Acta Geographica Sinica,2021,76(1):101-113. |
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| Authors: | CHAI Yuanfang DENG Jinyun YANG Yunping SUN Zhaohua LI Yitian ZHU Lingling |
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| Institution: | 1. State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan 430072, China2. Changjiang River Scientific Research Institute of Changjiang Water Resources Commission, Wuhan 430010, China3. Key Laboratory of Engineering Sediment, Tianjin Research Institutes for Water Transport Engineering, Ministry of Transport, Tianjin 300456, China4. Bureau of Hydrology, Changjiang Water Resources Commission, Wuhan 430010, China |
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| Abstract: | Water and sediment transport processes have been changed by the operation of larger scale reservoirs, which can result in the adjustments of river topography and water levels. The polynomial fitting method was applied to analyze the variation characteristics of the water levels under different characteristic water discharges in the Jingjiang reach of the Yangtze River during 1991-2016. The segregation variable method was used to estimate the contributions of the varied riverbed evaluation, the downstream controlled water level and the comprehensive roughness on the altered water level at the same flow. The results obtained are as follows:(1)The low water level in the Jingjiang reach of the Yangtze River during 1991-2016 presented a significant downward trend, and this trend intensified since 2009;riverbed scouring was the dominant factor for the reduced low water level, while the increased roughness alleviated this reduction.(2) During 1991-2016, the high water level decreased firstly and then increased. The variation characteristic of "high flood discharge with high water level" before 2003 transformed into "average flood discharge with high water level" since 2009. The increased comprehensive roughness was the main reason for the increased high water level, while the river scouring alleviated this increase. For navigation conditions and flood control, the intensifying riverbed scouring of the sandy reaches downstream dams enhanced the effects of the downstream water level on the upstream water level.(3) This led to the insufficient water depth in the reaches below dams, which should arouse great attention. The variation characteristics of high water level increased the flood pressure in the middle reaches of the Yangtze River. |
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| Keywords: | water level at the same flow spatio-temporal evolution channel geomorphology middle reaches of the Yangtze River |
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