| 引用本文: | 周炜兴,孙昭华,周坤,李芷晴,陈立.三峡水库蓄水前后长江中下游流量频率分布特征及其对洪水造床作用的影响.湖泊科学,2022,34(2):616-629. DOI:10.18307/2022.0221 |
| Zhou Weixing,Sun Zhaohua,Zhou Kun,Li Zhiqing,Chen Li.Characteristics of discharge frequency and their effects on flood channel formation in the middle and lower reaches of the Yangtze River before/after the impoundment of the Three Gorges Reservoir. J. Lake Sci.2022,34(2):616-629. DOI:10.18307/2022.0221 |
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| 摘要: |
| 三峡水库蓄水前后长江中下游流量特征变化及其对造床作用的影响一直受到学者的关注.采用枝城等6个水文站日均流量资料，分别统计了各站流量的经验频率分布，检验了8种概率密度函数的适用性，并讨论了三峡水库蓄水前后流量频率分布特征与造床流量的关系.研究表明：长江中下游干流洪中枯各级流量的频率分布具有分段特性，无法用皮尔逊Ш型或对数正态等常见函数来整体描述，但中洪流量区段符合分段幂函数；拟合得到的分段幂函数转折点可近似反映造床流量，包括临界值在内的函数特征参数受洞庭湖等调蓄作用影响，在螺山站上下游差异较大；三峡水库蓄水后，洪水削减使得各站的流量频率分段特性增强，分段幂函数仍然适用；由于三峡水库蓄水后流量过程变化和频率调整的影响，枝城、沙市、监利站造床流量将变为蓄水前的0.79、0.73、0.74倍，螺山、汉口、大通站造床流量将变为蓄水前的0.89、0.90、0.93倍.本文的方法和认识对于长江中下游径流特征分析和造床流量计算具有参考价值. |
| 关键词: 流量频率 概率密度函数 造床流量 河道萎缩 长江中下游 三峡水库 蓄水前 蓄水后 |
| DOI：10.18307/2022.0221 |
| 分类号: |
| 基金项目:国家自然科学基金项目（51879198，51579185）和水利部三峡后续工作项目（12630100100020J005）联合资助. |
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| Characteristics of discharge frequency and their effects on flood channel formation in the middle and lower reaches of the Yangtze River before/after the impoundment of the Three Gorges Reservoir |
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Zhou Weixing, Sun Zhaohua, Zhou Kun, Li Zhiqing, Chen Li
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State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan 430072, P. R. China
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| Abstract: |
| The variations of flow characteristics and their effects on channel formation in the middle and lower reaches of the Yangtze River before and after the impoundment of the Three Gorges Reservoir (TGR) have drawn much concern. Based on the data of the average daily discharge at six hydrological stations including Zhicheng Station, the empirical flow frequency distributions were calculated, and the applicabilities of eight probability density functions were tested. Furthermore, the relationships between the flow frequency distribution characteristics and the channel-forming discharges before and after the impoundment of the TGR were discussed. The results show that the flow frequency distributions in the study reach are segmented, which cannot be described as a whole by common functions such as Pearson Ш or Lognormal distribution. However, the frequency distributions of the medium-high flow conform to the broken power-law (BPL). The turning point of the BPL obtained by fitting approximately reflects the channel-forming discharge. Moreover, affected by the regulation and storage of Lake Dongting, the characteristic parameters including the critical values quite differently in the upper and lower reaches of Luoshan Station. After the TGR is impounded, the subsection characteristics of the flow frequency distributions are enhanced by the flood reduction, and the applicability of BPL are still considerable. Due to the influence of the flow process change and frequency adjustment by the impoundment of the TGR, the channel-forming discharge at Zhicheng, Shashi, Jianli, Luoshan, Hankou and Datong stations will be 0.79, 0.73, 0.74, 0.89, 0.90 and 0.93 times of that before the impoundment, respectively. The method presented in this paper are of reference value for the analysis of runoff characteristics and the calculation of channel-forming discharge in the middle and lower reaches of the Yangtze River. |
| Key words: Flow frequency probability density function channel-forming discharge river channel shrinkage middle and lower reaches of the Yangtze River Three Gorges Reservoir before the impoundment after the impoundment |
