胡腾飞,施勇,栾震宇,等. 长江宜昌—监利段河床冲淤对宜昌站水沙变化的响应[J]. 水利水运工程学报,2020(4):48-56. doi: 10.12170/2019062004
引用本文: 胡腾飞,施勇,栾震宇,等. 长江宜昌—监利段河床冲淤对宜昌站水沙变化的响应[J]. 水利水运工程学报,2020(4):48-56. doi: 10.12170/2019062004
(HU Tengfei, SHI Yong, LUAN Zhenyu, et al. Response of riverbed evolution of Yichang-Jianli reach of the Yangtze River to water and sediment conditions of Yichang Station[J]. Hydro-Science and Engineering, 2020(4): 48-56. (in Chinese)). doi: 10.12170/2019062004
Citation: (HU Tengfei, SHI Yong, LUAN Zhenyu, et al. Response of riverbed evolution of Yichang-Jianli reach of the Yangtze River to water and sediment conditions of Yichang Station[J]. Hydro-Science and Engineering, 2020(4): 48-56. (in Chinese)). doi: 10.12170/2019062004

长江宜昌—监利段河床冲淤对宜昌站水沙变化的响应

Response of riverbed evolution of Yichang-Jianli reach of the Yangtze River to water and sediment conditions of Yichang Station

  • 摘要: 三峡水库蓄水运行以来宜昌站水沙条件发生了明显改变,驱动下游河床发生新一轮调整。采用回归分析、机理分析等方法,探究了三峡工程运行前后长江宜昌—沙市段及沙市—监利段河床冲淤变化对宜昌水沙站条件的响应规律。结果表明:宜昌—沙市段冲淤量与宜昌站水沙指标间的关联度强于沙市—监利段且前者关联度随时间增强;研究河段月尺度河床演变对宜昌站水沙条件不存在明显的滞后响应;基于宜昌站月均流量分别构建的两个河段冲淤量回归模型可较好反映河床冲淤变化;根据所构建模型的模拟,三峡工程运行前宜昌—沙市段呈“小水小冲、大水大淤”的冲淤格局,冲淤转换临界宜昌站流量约为23 500 m3/s,三峡水库蓄水后该河段全面冲刷,呈“小水小冲、大水大冲”,但随着床沙粗化冲刷量有所下降;三峡水库蓄水前沙市—监利段亦呈“小水小冲,大水大淤”的冲淤格局,冲淤转换临界宜昌站流量约为22 500 m3/s,且同流量下的淤积量大于宜昌—沙市段,三峡水库蓄水后宜昌站小水时该河段冲刷量略大于上游河段,但宜昌站大水时该河段冲刷量明显更小。

     

    Abstract: Since the first impoundment of the Three Gorges Reservoir (TGR), water and sediment conditions of Yichang station have undergone a significant change, which has triggered a new round of riverbed adjustment of downstream reaches. In this study, regression analysis, mechanism analysis and other methods were used to investigate the response of the riverbed evolution of Yichang-Shashi reach (YSR) and Shashi-Jianli reach (SJR) to Yichang water and sediment conditions before and after the TGR. Results show that the correlation between scouring and silting amount (SSA) of YSR and Yichang water and sediment indexes is stronger than that of the SJR and the correlation of the former reach becomes stronger with time. On a monthly basis, the delayed response of riverbed evolution to Yichang water and sediment conditions cannot be observed for both YSR and SJR. Based on monthly average Yichang discharge, the univariate regression model for SSA can well reflect the riverbed evolution of both river reaches. According to the developed models, YSR riverbed before the TGR shows the pattern of “weak scouring under small discharge and strong silting under large discharge” and the critical Yichang discharge corresponding to the change of state is about 23,500 m3/s. After the TGR, YSR riverbed shows the characteristics of “weak scouring under small discharge and strong scouring under large discharge”. The scouring amount of YSR gradually decreases due to riverbed coarsening. SJR riverbed has the same evolution pattern with YSR riverbed before the TGR. However, its critical Yichang discharge of state change is slightly smaller (about 22,500 m3/s) and its silting amount is larger than that of YSR under the same Yichang discharge. After the TGR, SJR silting amount is slightly larger than that of YSR when Yichang discharge is small, while the former becomes much smaller than the latter when Yichang discharge is large.

     

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